Palm Oil Process - The Principle & Operational Techniques

Palm Oil Process The Principle & Operational Techniques

PALM OIL PROCESSING The Principles & Operational Techniques

Palm Oil Process The Principle & Operational Techniques

PREFACE This "handbook" has been prepared as a reference for the many engineers and other professionals who from time to time need to refresh their memory or update their knowledge on the principles and the operational techniques relating to the extraction and the recovery of Palm Oil and Palm Kernels from the fruit of the oil palm (Elaeis guineensis). They may be occupying the position of Mill Manager, Mill Engineer, Mill Superintendent, Laboratory Analyst etc. The book may also serve as a text book or reference for those wanting to pursue, or are already pursuing a career in this fascinating industry that directly combines large scale agricultural enterprises with industrial processing plants in a variety of different ways. There are five major sections to this book. The first is an introduction to the base product, i.e. the fresh fruit bunches from the oil palm, dealing with the fundamentals of its composition and (chemical) behaviour. This section also briefly describes the matters to be considered for harvesting, handling and transportation of the f.f.b. and deals therefore with those matters that effect or can affect the f.f.b. before reaching the processing plant. The second section describes the fundamentals and basic requirements to be considered when planning the locality, the type of process and the machinery required therefore. The third section explores, describes and details the unit operations normally found in a palm oil mill. The fourth section deals with the waste products generated, the disposal of it and the sources of pollution. The last section is an overview of all other activities and requirements that are normally associated with the operation of a palm oil mill, in particular the generation of steam and electricity, the maintenance of the machinery and equipment and the monitoring and evaluation techniques for the operation, administration, maintenance, stores, sales etc. It is impossible for me to acknowledge all the ideas of the many engineers, authors and friends whose experiences, added to my own during the forty years in engineering, may appear in this book. Fortunately I can acknowledge some of my friends and associates from whose world wide knowledge and experience in their specialized fields I gained during the past twenty four years in the palm oil industry and which has contributed to individual chapters in this book. These include: J.J.Olie; R.A.Gillbanks, MBE; ; T.Fleming; D.A.M.Whiting; K.L.Hammond; D.R.Hoare; J.C.Lumsden; Lim Kang Hoe; Dr.P.D.Turner; T.Menendez. Finally, I acknowledge that much of the material in this book is by no means new and/or complete but constitutes an attempt to amalgamate the information from published papers, manufacturers instruction books etc., with my personal knowledge, views and experience in this industry. J.A.Vugts.

Palm Oil Process The Principle & Operational Techniques

ABBREVIATIONS Admix. B.O.D. B.V. C.B.C. C.M.C. C.O.D. C.P.O. D E.F.B. F.F.A. F.F.B. H.R.T. Lotox M.P.D. M.V.A. N.O.S. P. P.K. P.K.E. P.K.O. P.O.M. P.O.M.E. P.V. S.S. T. T.D.S. T.O.C. T.O.D. Totox T.S. U.S.B. V.M.

: percentage foreign matter in kernel : Biological Oxygen Demand : Benzidine Value : Cake Breaker Conveyor : Cracked Mixture Conveyor : Chemical Oxygen Demand : Crude Palm Oil : Dura palm type : Empty Fruit Bunches : Free Fatty Acid : Fresh Fruit Bunches : Hydraulic Retention Time : Low total oxidation (value) : Mash Passing to Digesters : Melavonic Acid : Non Oily Solids : Pisifera palm type : Palm Kernel : Palm Kernel Expeller : Palm Kernel Oil : Palm Oil Mill : Palm Oil Mill Effluent : Peroxide Value : Suspended Solids : Tenera palm type : Total Dissolved Solids : Total Organic Carbon : Total Oxygen Demand : Total oxidation (value) : Total Solids : Un Stripped Bunches : Volatile Matter (moisture content)

Palm Oil Process The Principle & Operational Techniques

CONTENTS Preface Abrreviations used SECTION #1 The raw material - F.F.B. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Fresh Fruit Bunches Ripenes standards Bio chemistry Ripeness parameters Ripeness pattern Summary 1 to 5 Other factors of influence to F.F.B. Planting material Pollination Climate Soil condition Fertilizer Harvesting interval Transportation Summary 7 to 14

1-1 2-1 3-1 4-1 5-1 6-1 7-1 8-1 9-1 10-1 11-1 12-1 13-1 14-1 15-1

SECTION #2 The Factory - Design considerations 16. 17. 18. 19. 20. 21. 22.

Design Site selection Locality Effluent disposal Seasonal wind Transport distances Summary 16 to 21

16-1 17-1 18-1 19-1 20-1 21-1 22-1

SECTION #3 The Factory - Extraction of C.P.O. and P.K. 23. General requirements 24. Fresh fruit bunches 25. Sterilization of fruit 25.1 Air release 25.2 Condensate removal iii

23-1 24-1 25-1 25-3 25-6

Palm Oil Process The Principle & Operational Techniques 25.3 25.4 25.5 25.6 25.7 25.8

iv

Sterilizing cycle Steam consumption Operation Sterilized fruit to thresher machine Threshing or stripping the fruit Distribution sterilized fruit

25-7 25-9 25-19 25-20 25-21 25-25

26. Mash Passing to Digester 26.1 Introduction 26.2 Method of sampling 26.3 Analysis 26.4 Recording of results 26.5 Interpretation of results

26-1 26-1 26-1 26-2 26-2 26-3

27. Digesting of sterilized fruit 27.1 The digester 27.2 The action

27-1 27-1 27-1

28. Pressing of digested fruit 28.1 The press 28.2 The operation 28.3 The extraction efficiency

28-1 28-1 28-2 28-5

29. Crude Palm Oil (C.P.O.) 29.1 The collection of C.P.O. 29.2 The clarification of C.P.O. 29.3 The storage of C.P.O. 29.4 Evaluation of C.P.O.

29-1 29-1 29-3 29-9 29-10

30. Palm Kernel (P.K.) 30.1 Nut / Fibre mixture 30.2 The cake breaker conveyor 30.3 Nut / Fibre separation 30.4 Nut treatment 30.5 Nut cracking 30.6 Kernel / Shell separation 30.7 Kernel recovery 30.8 Kernel drying 30.9 Kernel cleaning 30.10 Evaluation of P.K.

30-1 30-1 30-1 30-3 30-8 30-9 30-10 30-13 30-13 30-14 30-15

Palm Oil Process The Principle & Operational Techniques SECTION #4 Waste products and pollution. 31.

v

Disposal of "dry" material 31.1 Solid waste products and disposal 31.2 The incinerator 31.3 The direct to field disposal 31.4 The use of E.F.B. as fuel 31.5 The fibrous material 31.6 The fuel value of fibre 31.7 The shell material 31.8 The fuel value of shell 31.9 The sludge (centrifuge) solids 31.10 Solids from Decanter systems 31.11 Solids from effluent treatment

31-1 31-1 31-1 31-2 31-3 31-3 31-4 31-4 31-5 31-5 31-6 31-6

32. Disposal of "wet" material 32.1 Parameters for liquid effluent 32.2 Biological Oxygen Demand (B.O.D.) 32.3 Chemical Oxygen Demand (C.O.D.) 32.4 Total Organic Carbon (T.O.C.) 32.5 Total Oxygen Demand (T.O.C.) 32.6 Theoretical Oxygen Demand (Th.O.C.) 32.7 Correlation of measurements 32.8 Biological treatment definitions 32.9 Aerobic suspended growth treatment 32.10 Control methods and technology 32.11 Treatment types 32.12 Anaerobic facultative pond system 32.13 Anaerobic (bi-phase) facultative ponds 32.14 Anaerobic/extended aeration pond system 32.15 Anaerobic tank digestion/extended aeration system 32.16 Land application of partly treated effluent 32.18 Effects of application of digested effluent

32-1 32-1 32-1 32-2 32-3 32-3 32-3 32-3 32-4 32-5 32-8 32-8 32-9 32-10 32-13

33. Air pollution 33.1 Boiler smoke 33.2 Incinerator smoke

33-1 33-1 33-3

32-13 32-17 32-18

Palm Oil Process The Principle & Operational Techniques SECTION #5

a) Steam and electricity generation b) Monitoring and Evaluation

34. Generation of steam and electricity 34.1 General boiler water information 34.2 Water treatment : external 34.3 Water treatment : internal 34.4 Blow down 34.5 The principle of de-aeration 34.6 Procedure for boiler "boil out" 34.7 Steam requirement calculations 34.8 Electricity

34-1 34-1 34-4 34-9 34-10 34-12 34-15 34-17 34-25

35. Repair and Maintenance 35.1 Maintenance and scheduling 35.2 Check list for reporting on Palm Oil Mills

35-1 35-1 35-7

36. Process control 36.1 The aim of process control 36.2 Examination of F.F.B. 36.3 Empty Bunch checking 36.4 Sampling 36.5 Interpretation of the results 36.6 General comments

36-1 36-1 36-2 36-4 36-5 36-7 36-8

37. Quality control 37.1 The Laboratory (37I).01 Determination of F.F.A. in C.P.O. (37I).02 Volatile matter in oil (37I).03 Dirt in oil 37.2 Oxidation 37.3 Bleach-ability 37.4 Quality analysis of P.K. 37.5 Determination of oil losses 37.6 Other tests

37-1 37-1 37-3 37-5 37-7 37-8 37-9 37-10 37-12 37-21

38. Administration and accounting

38-1

Glossary follows

vi

Palm Oil Process The Principle & Operational Techniques

SECTION #1 THE RAW MATERIAL [FRESH FRUIT BUNCHES]

1

Palm Oil Process The Principle & Operational Techniques

Chapter #1 FRESH FRUIT BUNCHES 1.01

"Oil is made in the field, and lost in the factory." This statement, as old as the industry itself, remains to be true, but provided both the field and the processing operation are well controlled, these losses can be controlled and kept within,(for the industry) acceptable parameters. Fresh Fruit Bunches (FFB) harvested from the oil palm trees, and the loose fruits that have already detached from the bunch whilst still on the tree are collected from "the fields" and both together are transported to the factory. The stage of ripeness at which this bunches are harvested and the condition of this fruit when delivered at the factory, determines to a large extend the efficiency of the extraction process and the quality of the products produced by the CPO factory.

1.02

The CPO factory produces Crude Palm Oil and Palm Kernel. Further processing of the CPO and the PK takes place in more specialised refineries, crushing and extraction plants. Theoretically, the exact point of ripeness or maximum oil content or yield from the fruit can be determined from a number of factors. Practically, one cannot expect that harvesters possess the knowledge as described hereunder and a usable compromise to obtain a harvest of a good average of fully ripe, mature FFB is required.

1.03

Various circumstances may determine the practical parameters, although the most used one remains the control of FFB by physical observation to determine the percentage "black and hard" bunches of the total FFB delivered. A full description of the most commonly used parameters can be found under the section 5, chapter 36 : Process Control.

1.04 2

Soil type and climatic conditions have a definite influence on the growth and

Palm Oil Process The Principle & Operational Techniques yield pattern of the oil palm (Elaeis guineensis). An average rainfall of 2000 millimetre or more per year and 5 to 7 hours sunshine per day are usually good parameters to secure an economically justified yield. Generally these conditions can be met in the tropical zone between 15 degrees North and 15 degrees South of the Equator, around the world. 1.05

Height increment (trunk elongation) ranges between 40 to 80 centimetre per year (pending on age, genetic type and conditions) and the yield of FFB follows a distinct pattern, changing with the age of the palm. Peak yields are generally obtained at the palm age of between 5 and 7 years old (when leave production is at maximum), and there after the yield declines to a reasonably steady pattern.

1.06

Both the male and the female "flowers" (inflorescences) grow on the same palm. Each inflorescence has a central stalk with spikelets carrying the flowers.

1.07

The male inflorescence can carry as many as or over a 1000 flowers, which produce between 20 and 50 grams of pollen during about 5 days. Pollen are released 2 to 3 days after the beginning of anthesis.

1.08

The female inflorescence carries a considerably larger number of flowers, the total varies, but can be several thousand flowers, pending on the arrangement of the central, upper and lower spikelets.

1.09

After pollination the female inflorescence develops into a fruit bunch, taking up to 22 weeks to become a fully developed and ripe bunch.

1.10

Each pollinated female flower may develop into an individual fruit in the bunch; its shape and weight varying depending on its geographical position in the bunch. The total bunch weight thus can vary considerably and ranges from about 10 kg to as much as 80 kg per bunch, the average weight usually varies between 15 and 30 kg.

1.11

3

An individual fruit consists of a seed (the "palm kernel"), surrounded by pericarp.

Palm Oil Process The Principle & Operational Techniques Pericarp includes three layers, i.e.: the hard endocarp (the "shell"), the fleshy mesocarp (the "fibre") which contains the palm oil and the thin outer skin or exocarp. 1.12

Oil palms can broadly be divided into three distinct types, i.e.: the Dura palm (D), the Tenera palm (T), and the Pisifera palm (P).

1.13

The nut of the Dura palm has a relatively thick shell (between 2 and 8 mm) and the percentage mesocarp to fruit is generally low (30 to 65 %). Dura fruit can be recognised when the fruit is cut transversely and no ring of fibres in the mesocarp close to the shell can be noticed.

1.14

The nut of the Tenera palm has a thinner shell than that of the Dura palm (between 0.5 and 3 mm) and the percentage mesocarp to fruit is higher (60 to 99%). Tenera fruit has the distinct and prominent ring of fibres close to the shell, clearly allowing identification of the fruit when cut.

1.15

The Pisifera palm fruit has a kernel but no shell.

1.16

Palm fruit may also develop even though no pollination appears to have taken place. These fruits are termed parthenocarpic fruit and although these can be oil bearing, they are usually small and with a solid centre, no kernel.

4

Palm Oil Process The Principle & Operational Techniques

Chapter #2 RIPENESS STANDARDS 2.01

Harvesting fruit bunches at the correct state of ripeness is of paramount importance in maximizing the oil yield.

2.02

It is generally accepted that for the maximum exploitation of the oil, the fruit bunch should be at its peak of ripeness. This is where the problem arises, basically on the uncertainty of the best time to harvest the fruit bunch to give the maximum product.

2.03

The conventional system is to determine the ripeness by the number of loose fruits detached from the bunch, i.e. 1,2,3 etc. loose fruits detached, or the amount of loose fruit per kilogram of estimated bunch weight, i.e. 10 to 25% detached fruits, etc. and any of these two criteria may be right.

2.04

An understanding of the formation of the various biochemical processes and the resulting palm products which normally either increase or decrease at the “ripe” stage may help to determine this stage of fruit ripeness.

5

Palm Oil Process The Principle & Operational Techniques

Chapter #3 BIO CHEMISTRY OF DEVELOPING OIL PALM FRUIT 3.01

Several distinct biochemical changes take place in the mesocarp as the fruit develops from flower to maturity.

3.02

Carbohydrates form the major biochemical constituent in the early stages of development. These are translocated from the main plant (palm), especially from the leaves, via the bunch stalk into the fruits.

3.03

The presence of Chlorophyll also contributes to the formation of carbohydrates. (The function of chlorophyll pigments is to generate carbohydrates by photosynthetic conversion of CO2 , H2O and light energy) For fruit development the need to have chlorophyll reduces and diminishes once the carbohydrates are utilised to form (storage) oil bodies.

3.04

Carbohydrates are continuously translocated and synthesised within the fruit until a certain stage whereby the carbohydrate "pool" is drastically converted to lipids.

3.05

Accessory pigments (such as carotene, orange plant pigment) and their isomers are also produced in the early stages of development and the amount increases proportionally with the increase in lipid content.

3.06

Tocopherols (naturally occurring trace elements, able to act as antioxidants) have been shown to increase in amount as the fruit matures.

3.07

In the early stages of development, lipids form only about one percent of the total weight of mesocarp and a large proportion of the lipids are phospholipids.

3.08

Phospholipids are important (at this stage) as an entity for cell wall and cell membrane formation.

6

Palm Oil Process The Principle & Operational Techniques (The proportion of phospholipids to total lipids remain none the less very low in ripe fruit.) 3.09

An important product of the carbohydrate metabolism is "tannin" (acidic substance). The amount of tannin in the fruit is constant throughout the development of the fruit.

3.10

Proteins, which function as the building blocks of cells and as enzymes for all biochemical reactions, also remain proportionally constant throughout the stages of development. (Proteins form only 0.1 % of the total biochemical products in ripe palm fruit)

3.11

The biosynthesis of lipids is the main feature exhibited by mesocarp. The precursor for lipid synthesis is carbohydrate. The conversion of carbohydrates to lipids takes place immediately after the kernel has fully developed.

3.12

The formation of lipids accelerate as the fruit approaches maturity and maximises at the ripe stage,(i.e. about the 20th week after pollination).

3.13

Senescence triggers the degradation (or hydrolysis) of lipids to glycerol and free fatty acids (FFA)

7

Palm Oil Process The Principle & Operational Techniques

Chapter #4 PARAMETERS FOR DETERMINING THE DEGREE OF RIPENESS Possible parameters are: a) b) c) d) e)

Lipid content Free Fatty Acid formation Moisture content Carotene :(Chlorophyll absorbency ratio) Carotene :(Carotene absorbency ratio)

a) Lipid content The amount maximises when fruit is ripe and the amount drops slightly after senescence. Total oil content increases with the age of the plant. The amount of oil in wet mesocarp increases from 1% in the young fruits to about 40 % in the mature fruits. The FFA composition of the mesocarp lipid at different stages of maturity is significantly different. In 11 week old fruits, linoleic acid (C18:2) is prominent, forming about 28% of the FFA composition. As the fruit matures, oleic acid (C18:1) forms the bulk of the lipid. In the ripe fruit the FFA composition of the lipid extract is similar to that of the CPO (see table 1) It is only natural that the product which is generated by the plant maximises at the mature stage and the composition is such to provide the fruit with lipids containing the basic fatty acid precursors for the subsequent process of dispersion and survival.

8

Palm Oil Process The Principle & Operational Techniques b) Free Fatty Acid formation Degradation of lipids occurs after senescence and also in bruised, mature fruits. (Senescence is the immediate phenomenon following the fully mature fruit stage) The metabolism of biochemical substrate stops. Instead, degradation of some of these products, especially lipids take place. The action of lipases on the lipids is responsible for catalysing the formation of FFA's and glycerol’s. Lipases may be derived from within the mesocarp or contributed by bacteria, yeast’s and other microbial infections. Substantial amounts of free fatty acids are formed in the senescenced fruit. (see table 2) In the fruit, FFA's constitute about 0.8% of the total lipid and may increase to 9 or 10% after the fruits are detached from the bunch. c) Moisture content Water forms the major constituent in plants, for it is very important as a medium for transport, for biochemical reactions and as a solvent. It is very important when fruit is at the young stage, whereby development requires the precursors to be water soluble. Water is also the source of hydroxyl groups for biochemical reactions. The need to have excess water is reduced as the function of the cells in the mesocarp becomes more specialised. It is expected that in palm fruit the amount of water per gram mesocarp is least at the ripe fruit stage. 80% of the total weight of 11 week old mesocarp is water and the percentage reduces to about 30 to 40% in the ripe fruit. It has also been shown that the amount of water in the detached fruit is considerably lower (± 25 to 30 %, see table 3) 9

Palm Oil Process The Principle & Operational Techniques (A certain drop in the proportion of water in the fruit could trigger the fruits to senescence.) d) Carotene: Chlorophyll absorbency ratio The formation of various biochemical palm products for example: lipids, carotenes, tocopherols; all of which normally maximise at the mature stage are not the only processes that are occurring in the plant. The degradation of these products may also occur and these happen in fully ripe and damaged or infected fruits. (Degradation of biochemical products which are formed at the early stages of development and have no further contribution to the fruit may also occur.) The products include chlorophyll and the all important Carbo hydrates. Carbohydrates are converted to potential intermediates for lipid synthesis, as are chlorophyll’s. Ripe fruits DO NOT contain any chlorophyll pigments, the drop in the chlorophyll content has been shown to be proportional to the increase in lipid and the carotene content. This distinct change provides additional information with respect to the degree of ripeness of the fruit. Chlorophyll pigments are not detectable in the ripe fruit, but their presence is always detectable and have been measured in the younger fruits. Chlorophyll content increases and then decreases at the later stage and is absent in the ripe fruit. Spectral scanning of the extracts of mesocarp of various ages has provided some accurate judgement of ripe and unripe fruits. Carotenes are always present, even in the very young fruits. The "yellowing" of the mesocarp as the fruit ripens is due to the degradation of chlorophyll’s and the build up of carotenes. 10

Palm Oil Process The Principle & Operational Techniques In younger fruits, chlorophyll’s form the main photosynthetic pigment for the synthesis of carbohydrates. The carotenes at this stage function as accessory pigment during the photosynthetic process. The ratio of carotene to chlorophyll content at different stages of development is therefore useful in determining the age of the fruit and can be used as an indicator for ripeness standard. (under laboratory conditions) e) Carotene : Carotene absorbency ratio The biosynthesis of carotene in oil palm is similar to that of other plants. The basic precursor is carbohydrate which undergoes biochemical changes, firstly to acetyl CoA. This acetyl CoA will subsequently be converted to melavonic acid (m.v.a.), isopentenyl pyrophosphate (i.p.p.) and finally polymerisation of these i.p.p's to carotenes. These carotenes are accessory pigments found in the protoplasts or chloroplasts. A typical spectrum of carotene distribution of crude palm oil is identical to that of the distribution of ripe mesocarp extract. Carotene extracts of ripe mesocarp exhibits three absorbency peaks: at 432 nm, 456 nm and 480 nm. Maximum absorbency is at 456 nm for mature and ripe fruits. Younger fruits, where the chlorophyll pigments are present have a maximum absorbency of 432 nm. As the fruit develop to maturity, the absorbency at 432 nm decreases to a stage where the absorbency at this wavelength is lower than that of 456nm. At the same time the absorbency at 664 nm for chlorophyll’s also decreases, and finally disappears. The ratio of absorbency at 456 nm and 432 nm formulated may be useful as an indicator to determine the degree of ripeness of the fruit.

11

Palm Oil Process The Principle & Operational Techniques A 456 : 432 nm absorbency ratio with a value < 1 may indicate young fruit. 14th to 16th week old fruits have ratios from 0.8 to 1.0. Mature fruits (18th/19th week) normally have values of 1.0 to 1.2, (and at the same time exhibit an absorbency peak at 664 nm, which indicates the presence of chlorophyll’s) In ripe and senescenced fruit, the 456 :432 nm absorbency ratio is 1.2, and do not exhibit any chlorophyll absorbency peak at 664 nm. This ratio has also been applied to study the various different degrees of development of fruit that occur in the bunch itself. Controversy of whether there is a need to allow all the fruits to be completely developed before harvesting can be solved by this carotene: chlorophyll absorbency ratio system.

12

Palm Oil Process The Principle & Operational Techniques

Chapter #5 RIPENESS PATTERN [relation of a ripe fruitlet to the rest of the bunch] 5.01

Ripe fruit may be defined as fruit which has the maximum amount of oil, and more directly as fruit which contains no more chlorophyll’s and attaining a carotene to carotene absorbency ratio of > 1.2 (which occurs normally in the 20th week after anthesis.)

5.02

The fruits of any given bunch do not ripen simultaneously, due to slight variations in the time of pollination of the flowers. (The period of receptivity of the florets in an anthesizing female inflorescence is about 2 to 5 days.)

5.03

Visual observation indicate that both the size and the colour of the fruit from the different locations on the bunch are different. The fruits on the periphery (outer side) of the bunch are usually large and deep orange in colour, whilst the fruits embedded in the interior of the bunch are sometimes smaller and do not have the deep orange coloration. Correlation of all these fruits with one another in terms of the degree of ripeness can be made.

5.04

Analysis done on the same bunch of a particular age, from different bunch sections, i.e. top, middle and bottom and from each section from different spikelets, i.e. outer, middle and inner parts shows that the contents of chlorophyll’s and carotenes are more in the top sections and decreases towards the bottom, but the 456 : 432 nm absorbency ratio is at a constant value, i.e. < 1.

5.05

This constant value indicates that the fruits from different sections are all in a similar stage of maturity.

5.06

Unless: the absorbency ratio of the top section is equal or more than 1, which would indicate that the fruits in that section are older than the fruits in the middle or bottom section of the bunch.

5.07

Analysis from the 20th week (optimum ripeness) show a similar absorbency profile; in all the fruits from whatever position on the bunch.

13

Palm Oil Process The Principle & Operational Techniques 5.08

Another criterium to constitute the finding that the fruit on the different bunch and spikelet section are of similar physiological age is the fatty acid composition of the fruits from these different sections.

5.09

It can be seen that the distribution of fatty acid in the fruits, from various sections have a similar pattern. The contents of the major fatty acids such as Palmitic Acid (C16:0) and the C18 fatty acids, i.e. Oleic Acids (C18:1) and Linoleic Acids (C18:2) are quite similar.

5.10

The fatty acid distribution profile is similar within a bunch, although the oil content in the outer fruits is higher and decreases towards the inner portion of the bunch. This is due to the intrinsic property of the fruit by virtue of its position on the bunch.

14

Palm Oil Process The Principle & Operational Techniques

Chapter 6 SUMMARY [chapters 1 to 5] 6.01

The conversion of carbohydrates to lipids at about the 13th week of development appears to be the main function of the fruit at this stage of its development.

6.02

The accumulations of tocopherols and carotenes are proportional to the build up of oil.

6.03

Carbohydrates are synthesized by the fruit during this stage, but at a decreasing rate.

6.04

Since the indications are that most of the fruits in the bunch are of similar physiological age, it is therefore not necessary to wait to harvest the bunch, ONCE THERE ARE SIGNS THAT SOME OF THE FRUITS ARE RIPE. Table#1 Fatty acid composition in % C type

AGE OF FRUIT IN WEEKS 11

15

12

RIPE

13

C.P.O.

14

12

0.22

-

-

-

-

-

14

0.62

0.6

0.8

0.5

1.7

0.2

16

27.8

38.9

37.2

39.6

44.9

44

16:1

1.06

-

-

-

-

-

18

4.12

5.1

5.2

4.9

4.0

4.5

18:1

14.4

18.4

22.0

32.6

37.3

39.2

18:2

28.8

25.6

24.4

19.3

14.4

10.1

18:3

22.3

10.9

9.8

2.7

0.3

0.4

20

0.77

0.3

-

0.3

0.3

0.4

17

-

0.2

0.6

0.2

-

-

Palm Oil Process The Principle & Operational Techniques Table #2 Fatty acid content Sample:

Volume NaOH in (McOH)

% FFA

7th week (young fruit)

0.2 ml

0.1

Ripe fruit

0.5 - 1 ml

Ripe fruit (easily detached)

2.5 ml

1.3

Senescened fruit

10.8 ml

5.5

0.25 - 0.5

Table #3 Oil and Moisture Content Sample:

16

oil / bunch

oil / fruit

Moisture

Ripe fruit (mill)

20 %

-

22 %

Ripe fruit (laboratory)

30 %

45 %

40 %

8th week (laboratory

-

7%) can support the growth of a mould that leads to an increased rate of hydrolysis of the palm kernel oil extracted from this kernel, i.e. an increase in F.F.A. The enzyme causing this is produced by the mould growth and can withstand quite high temperatures, thus the drying after the mould has developed will only enhance the appearance of the kernel, but will not prevent the later quick deterioration of the kernel oil since the enzyme will remain active in the palm kernel oil.

117

Palm Oil Process The Principle & Operational Techniques 30.8

KERNEL DRYING

30.8.01 Kernel drying is most commonly achieved by the "continuous" type silo dryers. Drying is achieved by blowing hot or warm air through the kernels at the bottom, the middle and the top level sections of the silo at different temperatures. The coldest being at the bottom, the hottest being at the top section of the silo. Too high an air temperature (>85o C) could cause discolouration of the kernel (and thus the kernel oil extracted there from) and must be avoided. Thus retention times can be quite long and rather large capacity drying silos will be needed. Here again the advantages of the dry separation method show up quite clearly, since the lower initial moisture content will allow lower drying air temperatures and shorter retention times to dry the kernel to the required moisture content. The resulting end product will be of higher quality. Despite the term "continuous" dryer, this type of drying in practice really works out to be more of the "batch" type operation. Continuous drying , where kernel is moved continuously on slowmoving conveyor belt or tables has been tried as an alternate method and proved to be quite successful, producing well dried good quality kernel. The preferred method thus depends very much on a design philosophy and economical considerations. 30.9

KERNEL CLEANING

30.9.01 Kernel cleaning, after the drying process consists mainly of the removal of dirt and shell debris, loose fibre and fragments of broken kernel. This can be done mechanically, by air separation or by hand. Much depends on the quality of the process before the drying stage, but invariably shells and shell particles which adhered to the kernel before the drying process will have come loose during this process, partly due to the reduction in moisture (size) of the kernel and partly 118

Palm Oil Process The Principle & Operational Techniques due to the rubbing action and the overall friction encountered in the silos. In some cases a simple "seed cleaning" device as used commonly in the grain and other seed industries can be adapted and successfully applied here. The degree of "cleanliness" is expressed as the "percentage admixture" and is generally largely defined by the end use or user of the palm kernel. 30.10. EVALUATION OF P.K. 30.10.1 Fosfa recognizes several contracts, i.e. Product

Basis of Sale

Contact

Quality % Quantity determination

Palm kernel

C.I.F.

Fosfa 29

at destination

Palm kernel

F.O.B.

Fosfa 79

at destination or shipment as agreed between buyer/seller

[Similar contracts exist for Palm Kernel Expeller (P.K.E.)] Market patterns change from time to time, but the majority is sold on a C.I.F. basis.

30.10.2 Comparison of "Outturn Quality" Good Quality P.K [%] Oil content

49.5

Poor Quality P.K [%] 47.00

F.F.A

4.25

9.75

Shell and Dirt

6.00

10.00

Sale of 500 MT @ US$ 200,- /tonne Shipped

500 tonne @ US$ 200,-

= 100,000.-

= 100,000.-

Outturn = 487 tonne ———————————————— Shortage

13 tonne

=

2,600.-

=

2,600.-

———————————————— Outturn value

119

= 97,400.-

= 97,400.-

Palm Oil Process The Principle & Operational Techniques Good Quality a)

Poor Quality

Oil content Contract basis Out turn

49.0%

49%

49.5%

47%

———————————————— Premium / Penalty

b)

+0.5%

-2%

+0.5 x 1.3% = +0.65%

-2 x 1.3%= -2.6%

F.F.A content

4.75%

4.75%

Out turn

4.25%

9.75%

———————————————— Premium / Penalty

+0.5%

-5.0%

+0.5 x 0.75= +0.38%

-5 x 0.75= -3.75%

Shell and Dirt: Contract basis

2.75%

2.75%

Out turn

6.00%

10.00%

———————————————— Penalty

-2.25 x 1%= -2.25

-2.25 x 1%= -2.25

-1.00 x 2%= -2.00

-2.00 x 2%= -4.00

-2.00 x 3%= -6.00

-1.00 x 4%= -4.00

———————————————— Total penalty

-3.22%

-22.60%

Out turn value

97,400.-

97,400.-

Penalty

-3.22% = 3,136.28

-22.6% = 22,012.40

———————————————— Net Value

94,263.72

75,387.60

Difference between good and poor quality = US$ 18876.12 or US$ 37.75 per tonne.

Poor quality kernel gives rise to large crushing losses, which is why the specifications have been set to the following indicative levels: Oil content F.F.A Dirt & Shell Moisture

120

over 49% under 4% under 6% under 7%

Palm Oil Process The Principle & Operational Techniques CALCULATIONS FOR NUT TRANSPORT/DESTONER SYSTEM: 1) Known Data Nut throughput

: 5.25 ton/hr

Lifting velocity nuts

: 40 m/sec

Conveying velocity

: 30 m/sec

Separation velocity

: up to 8 m/sec

Air ratio per kg conveyed nut

: 2.5 : 1

Density of air at 27 oC

: 1.177 kg/m3

2) Unknown data (to be calculated) Air flow rate Static pressure requirement Size of lifting column Size of separating section Size of transport pipe or duct 3) Calculation a) Air required to convey 5250 kg nuts per hour = 5250 x 2.5 kg/hr = 13125 kg/hr Airflow rate = 13125 kg/hr : 1.177 kg/m3 = 11151 m3/hr Losses due to speed reduction @ 2 %, losses due to leakage etc. @ 10 %, calculate to actual flow rate of = 11151 x 1.12 = 12489 m3/hr. b) Suction pressure required: for pick up nuts from rest

= ± 125 mm WG

pressure loss in ducting and column

= ± 125 mm WG

pressure loss in cyclone

= ± 75 mm WG ————————

Total

121

= ± 325 mm WG

Palm Oil Process The Principle & Operational Techniques c) Cross section area for lifting column: With lifting velocity of 35 m/sec and flow rate of 12489 m3/hr = 12489 —————— = 0.086729 m2 60 x 60 x 4 Column diameter = 0.3323 meter d) Cross section area for the conveying pipe or duct: With velocity of 30 m/sec and flow rate 12489 m3/hr, cross section area = 0.11564 m2, and diameter of transport pipe = 0.3837 meter e) Cross section area for the separating column: With velocity of 8 m/sec and flow rate 12489 m3/hr, the minimum cross section area required would be: 0.43365m2 For a circular separating column the diameter calculates to 0.5521 meter. To be "on the safe side" and to suit commercially available equipment, a 12" diameter pipe (= ±0.31 meter) for the lifting column can be used. Conveying ducting can be rounded of to 0.38 meter diameter. Fan capacity selected should be rounded up to the nearest commercially available , usually 15000 m3 @ 500 mm WG.

ACTION FOR FPII: 1) FPII should check the measurements and data of their existing equipment and compare with above theoretical calculations to ensure that at least the minimum requirements are met. 2) The schematic diagram no 1 shows the principle lay out of the system. FPII should compare with what they have and determine what additional material, equipment etc. they may require. 3) The lay out as shown on sketch 2 is simple and direct, but it does require a minimum difference in height between nut inlet and separating box outlet of at least 8 meters. That should be possible in FPII, and it will eliminate the need for the now used single chain bucket elevator. 122

Palm Oil Process The Principle & Operational Techniques

SECTION #4 THE FACTORY WASTE PRODUCT & POLLUTION

123

Palm Oil Process The Principle & Operational Techniques

Chapter #31 DISPOSAL OF "DRY" MATERIAL 31.1

Solid waste products and disposal.

31.1.01 The major source and nature of solid "wastes" from C.P.O. mills are: a) Empty Fruit Bunches b) Fibrous matter c) Shell material d) Solids ex centrifuges e) Solids ex Decanters

± 22-25% ±13-15% ±4-6% ±0.5-1.0% ±1.5-2.5%

of F.F.B. weight. of F.F.B. weight. of F.F.B. weight. of F.F.B. weight. of F.F.B. weight.

Processing F.F.B. to the stages of C.P.O. and P.K. continuously generates these solid products, whilst the liquid effluent treatment generates "wet" (sludge) solids. These solids are removed from the anaerobic ponds and/or settling tanks with periodic intervals depending on the load of the system. (see 31.11 solids from effluent treatment) The Empty Fruit Bunches (E.F.B.) can be dealt with in two different ways: 31.2.

The incinerator

31.2.01 E.F.B. from the mills process is transported directly from the outlet of the threshing machine to the inlet of the incinerator usually by means of open, slat type conveyors. Various types of incinerators have evolved over the years, but the underlying principle remained the same, i.e. a slow, low temperature "burning" or incineration of the (still wet) bunches on an inclined grate. The combined effect of a thick layer of E.F.B. and only natural draught conditions cause a slow and steady process of converting the E.F.B. into ashes. The 124

combustion

efficiency

is

seldom

optimum

under

these

Palm Oil Process The Principle & Operational Techniques circumstances and the resulting stack plume from the incinerator chimney stack is characteristic. (see also under 33. air pollution) 31.2.02 Bunch ash is rich in potassium and has an ameliorating effect on acid sulphate soils and improves the soil pH. 31.2.03 Average nutrient values of bunch ash from incineration E.F.B. produces about 4.5 % ash on wet bunch weight, or an equivalent of about 10 % ash on dry bunch weight, with an approximate value of: 30-40 % K2O 3-5 % P2O5 ±7.5 % CaO The basic nutrient requirements of an oil palm are Nitrogen, Phosphorus, Potassium or Magnesium. The ratio will depend on the soil type and the area, thus the rate of application also varies, pending local conditions. (A soil inclined to leach will require a heavier application then one of a more colloidal structure) Mature oil palms, planted at a density of 135 palms per hectare remove from the soil annually approximately in K = ±40 kilograms, in N = ±15 kilograms, in P = ±6 kilograms and it would therefore be a powerful soil which could sustain such depletion without some return of the elements used. 31.3

The direct field disposal

31.3.01 E.F.B. are also rich in plant nutrients, making mulching an alternative method of disposal. Mulching E.F.B. utilizes the full potential nutrient and soil enriching properties, whilst there is no source for air pollution. On analysis of E.F.B. it is usually found that the values are approximately: N = ±14 %, P2O5 = ± 0.03 % and K2O = ± 0.45 %.

125

Palm Oil Process The Principle & Operational Techniques A complete ground cover in the inter rows of planting can take as much as 200 tonnes of E.F.B. per hectare, returning to the soil an approximate nutrient value of: N = 250 kg/ha, P2O5 = 50 kg/ha and K2O = 800 kg/ha, which is quite a valuable dressing. Added to this are the physical benefits if humus to the soil and soil water conservation. (Whole) bunches are placed in between the palm trees and allowed to decompose naturally. In relative flat terrain, mulching in this way can be easily effected using standard tractor trailer units or their normally used equivalent to transport the E.F.B. The economic consideration, i.e. the cost of mulching per hectare versus the fertilizer cost per hectare may be the decisive factor. 31.3.02 It is possible to convert from a mill with conventional incineration to a direct field disposal system for E.F.B. with minimal direct cost to the mill, but the cost of the possibly required extra transport units to transport the quite considerable bulk of the E.F.B. (average = ±25 % of F.F.B weight). 31.4

The use of E.F.B as supplementary fuel

31.4.01 The very high moisture content of the E.F.B. necessitates pre drying, if these bunches are effectively to be used as additional fuel in the boiler furnace, since their calorific value when wet is low (±1050 kcal/kg) The calorific value of dried E.F.B. varies considerably with the oil content of the material and on average (with an oil content of 3 %) can be taken as between ± 2300 and 2350 kcal/kg. 31.4.02 Most factories do not use the E.F.B. as fuel, since the combined fibrous matter and shell provide sufficient fuel to operate and create a surplus which can be used for starting up periods etc.

126

Palm Oil Process The Principle & Operational Techniques 31.5

The fibrous material

31.5.01 All fibre produced by the process is normally used for boiler fuel. Pending the steam/power/fuel balance, this is normally sufficient to ensure adequate fuel supply, more so since it is mixed with the available shell. Surplus fuel is normally stored near the boiler(s) for reserve purposes during periods of low production, start up periods and, if sufficient reserves can be accumulated, to maintain boiler operation during part of the non producing periods to reduce the costs of power generation by means of diesel oil fuelled diesel generating sets. 31.5.02 Fibre is "dry" when oil has been extracted and free moisture flashed off during its transportation from the pressing station to the boiler feeding or storage area, but still has a certain moisture content. (between 30 and 35 %) It requires no further treatment and can be directly utilized as fuel in the boiler furnace. 31.5.03 Fibre when burned as fuel produces approximately: 10% ash on dry matter and this contains approximately: 20-30% K2O , 4-6% P2O5 and 10% CaO. The ashes can be conveniently disposed of in various ways, usually as a road topping for the non sealed roads in the mill/plantation areas and are thus not considered as an environmental threat. 31.6

The fuel value of fibre

31.6.01 The moisture content of the fibre used for fuel and the oil content of the fibre largely determine the calorific value available from this material. The oil loss on dry fibre is on average about 8 %, whilst the moisture content can vary between 30 and 40 %. Thus the calorific value available from this material can vary considerably, but on average remains between 2500 and 3600 kcal/kg which is sufficiently high to be used in the boiler furnace, but on it’s own is insufficient to generate sufficient heat to produce the required amounts of steam.

127

Palm Oil Process The Principle & Operational Techniques 31.6.02 It is for this reason that this fuel must be mixed with the shell which is produced, or mixed with other suitable fuel to enable sufficient heat to be generated. 31.7 The shell material 31.7.01 After the cracking of the palm nuts and the separation of the shell and kernel, the shell is transported to the boiler fuel feed or storage area and mixed with the fibrous material. The mixing can quite simply be achieved by feeding the shell to one or more of the conveyors which transport the fibrous material. 31.7.02 The shell (after the drying process of the nuts, the cracking and the usually pneumatic transportation) have moisture content varying between 12% and 18% although this can vary considerably depending on whether wet or dry separation of the shell and kernel is practised. The oil content, for the purpose of fuel, is negligible. 31.8

The fuel value of shell

31.8.01 There has been a difference established between the calorific values of "old" shell and "fresh" shell. For the purpose of determining the fuel value this can be ignored. Shell has on average a calorific value of between 3500 and 4000 kcal / kg and it will be noted that this is quite a lot higher than that of the fibrous material. 31.8.02 Under the normally prevailing conditions in a boiler furnace, shell burns very hot and its silica content produces a hard, solid slag/clinker which is difficult to remove from the furnace grate bars etc. It is for this reason that a mixture of fibre and shell is used and that the ratio of this mixture is controlled by regulating the quantity of shell added to the fibre and regularly analyzing samples taken from this mixture. 31.8.03 Shell produce approximately 2% ash and this contains approximately : 55-85% Silicic acid , 4-5% P2O5 and 2-3 % K2O.

128

Palm Oil Process The Principle & Operational Techniques The ashes, being mixed with the ashes from the fibrous material, are disposed of as described above. 31.9

The sludge centrifuge solids

31.9.01 Centrifuge sludge has a good plant nutrient value and can be disposed of together with the E.F.B, if mulching is practised. Sludge (evaporated sludge) has an ash content of about 10 % and contains approximately: 20-30% K2O , 4-8% P2O5 and 10% CaO. The advantage of disposal with the bunch mulch is that the sludge becomes trapped by the bunches and is not readily washed off by the surface run off. 31.9.02 If mulching is not practised, these solids can be applied directly to the land. 31.10

Solids from Decanter systems

31.10.1 A typical C.P.O. factory generates a total effluent of ± 70 % from the clarification processes. The basic principle of a decanter system is to reduce or eliminate the effluent discharge either partially or totally, in order to reduce the total effluent volume. 31.10.2 Some decanter systems do not require the reduction of the viscosity of the crude oil by means of dilution and thus the resulting solids phase has a very low moisture content. Evaporation and flash off of this moisture produces a virtually "dry" cake which is easily handled. The dried cake, known as "palm oil meal" has been used both as a fertilizer and as a component in animal feed. This system usually utilizes the waste heat from the boiler flue gases to dry the solids from both the decanter and the nozzle separators. Such driers simultaneously serve as a "scrubber", thus reducing the particle emission in the flue gases of the boilers. 129

Palm Oil Process The Principle & Operational Techniques 31.10.3 The obvious benefits are the reduced effluent load to be treated, possible benefits from the sale value of the dried cake and (if applicable) the reduced particle emission of the flue gases. However, initial capital costs are quite high and the recurring maintenance costs and skills required are also quite high. Thus, the economics often dictate against the use of these systems. 31.11

The solids from liquid effluent treatment

31.11.1 These solids can also be directly applied as fertilizer to the oil palm plantings, but since the wet volumes are large, the sludge is first dewatered usually on sand beds, to reduce the volume and facilitate handling. 31.11.2 De-watering occurs by evaporation under natural sunlight and by percolation and/or drainage of the (free) water into the sand beds. The resulting solids "cake" can then be applied to the land, a typical application would be: for anaerobic sludge cake : 0.1 tonne per tonne of F.F.B. for aerobic sludge cake : 0.05 tonne per tonne of F.F.B. Again, economic considerations are often the deciding factor, although with the increased emphasis on environmental and pollution control over the last decade, the choice has become more limited.

130

Palm Oil Process The Principle & Operational Techniques

Chapter #32 DISPOSAL OF "WET" MATERIAL 32.1

General parameters for Palm Oil Mill liquid Effluent. (P.O.M.E.) PARAMETER

1989

1991

1993

1995

B.O.D.

1000

500

200

100

C.O.D.

2000

1000

400

200

TOTAL SOLIDS

2000

1500

1500

1500

SUSPENDED SOLIDS

600

400

400

400

OIL

75

50

50

50

N-NH3

20

10

5

2

pH

6-9

6-9

6-9

6-9

These standards are acceptable for the industry and are approximately equal to those set in major oil palm growing areas. (Malaysia / Indonesia). 32.2

Terms and conventions used for general effluent descriptions:

32.2.01 Biological Oxygen Demand (B.O.D.) The calculation used to measure in milligram per litre, for percent mixtures: B.O.D.(mg/l) = [ ( D.O.b - D.O.i ) 100 : % ] - ( D.O.b -D.O.i) D.O.b , D.O.i = Dissolved Oxygen values found in blank (contains dilution water only) and dilutions of sample, respectively , at end of incubation period. D.O.s = Dissolved Oxygen originally present in undiluted sample. With B.O.D. > 200 mg/l, D.O.s is nearly = D.O.b and the second part of the formula becomes negligible. 131

Palm Oil Process The Principle & Operational Techniques 32.2.02 Biochemical oxidation is a slow process, theoretically infinite. Within a 20-day period, oxidation is approximately 95 to 99 %, and in the 5 - day period used for the B.O.D test is plus/minus 60 to 70 % complete. (the 5 day period is commonly notated as B.O.D.5 ) Tests can be either (in laboratory) by a Warburg Respiro meter (for slow and small samples ) or by an electrolytic respiro meter, usually with multiple electrolysis cells. The advantage is: 1) usage of a large (1 litre) sample, minimizes the errors of "grab sampling" and pipetting in dilutions. 2) value of B.O.D is directly available. 32.2.03 B.O.D testing has severe limitations: 1) a high concentration of active, acclimated seed bacteria is required 2) pretreatment is needed for toxic wastes and the efforts of nitrifying organisms must be reduced. 3) only the bio degradable organisms are measured 4) test is not valid after the soluble organic matter present in the solution has been used. 5) Arbitrary, long period required to obtain results. 32.3

Chemical Oxygen Demand (C.O.D.)

32.3.01 Used to measure the content of organic matter of both waste water, (effluent) and natural water. The oxygen equivalent of the organic matter that can be oxidized is measured by using a strong chemical oxidizing agent in an acidic medium. (Potassium di-chromate for example) A catalyst (silver sulphate) is required. Some organic components interfere, care must be taken to eliminate these. C.O.D is also used to measure the organic matter in wastes that are toxic to biological life. 32.3.02 The C.O.D of a waste is generally higher then the B.O.D. , because more compounds can be chemically oxidized then can be biologically oxidized. 132

Palm Oil Process The Principle & Operational Techniques Usually it is possible to correlate C.O.D. with B.O.D. , which is useful, since C.O.D. can be determined in about 3 hours. Once a correlation has been established, it can be used to advantage for treatment control and operation. 32.4

Total Organic Carbon (T.O.C)

32.4.01 This is used for measuring organic matter present in water and is especially applicable to small concentrations of organic matter. The test is performed by injecting a small, known, quantity in a high temperature furnace, where the organic matter is oxidized to carbon dioxide in the presence of a catalyst. The CO2 is measured quantitatively by means of an infra red analyser. Test is very quick, but certain organic compounds resist being oxidized and the measured T.O.C. value will be slightly less than the actual amount. 32.5

Total Oxygen Demand (T.O.D.)

32.5.01 Organic matter are converted to stable end products in a platinum catalysed combustion chamber. T.O.D. is determined by monitoring the oxygen contend present in the carrier gas (nitrogen) Rapid testing and the results can be correlated with C.O.D. results. 32.6

Theoretical Oxygen Demand (Th.O.D.)

32.6.01 If the chemical formula is known, then Th.O.D. may be computed from this formula, expressed usually in gram O2/mol. 32.7

Correlation among the various measurements.

32.7.01 This depends primarily on the nature of the waste water, effluent and its source. If a good correlation can be established, then because of the rapidity of the C.O.D., T.O.C. and the T.O.D. tests, this can be very useful and eliminates or reduces the time to get B.O.D results directly.

133

Palm Oil Process The Principle & Operational Techniques 32.7.02 Example ratios' for untreated wastes are: B.O.D.5 / C.O.D. = 0.4 - 0.8 , B.O.D.5 / T.O.C = 1.0 - 1.6 etc. Once established, these ratio's can be used to calculate the B.O.D content to a close enough degree for control of plants etc. quite quickly. 32.8

Biological treatment: definitions

32.8.01 AEROBIC processes are biological treatment processes that occur in the presence of oxygen. Certain bacteria that survive only in the presence of dissolved oxygen are known as obligate (restricted to special conditions in life) aerobes. 32.8.02 ANAEROBIC processes are biological treatment processes that occur in the absence ofoxygen. Bacteria that can only survive in the absence of any dissolved oxygen are known as obligate anaerobes. 32.8.03 ANOXIC DENITRIFICATION is the process by which Nitrate nitrogen is converted biologically into nitrogen gas in the absence of oxygen. The process is also known as Anaerobic denitrification. 32.8.04 FACULTATIVE PROCESSES are biological treatment processes in which the organisms are indifferent to the presence of dissolved oxygen. These organisms are known as facultative micro organisms. 32.8.05 MICRO AEROPHILS are a group of micro organisms that grow best in the presence of low concentrations of oxygen. 32.8.06 CARBONACEOUS B.O.D. removal is the biological conversion of the carbonaceous organic matter in effluent into cell tissue and various gaseous end products. In this conversion it is assumed that the nitrogen present in the various compounds is converted to ammonia. 32.8.07 NITRIFICATION is the two stage biological process by which nitrate is converted to nitrogen and other gaseous end products. 32.8.08 STABILIZATION is the biological process by which organic matter in sludge produced from primary settling ponds and the biological treatment of effluent is stabilized, usually by conversion to gases and cell tissue. 134

Palm Oil Process The Principle & Operational Techniques Depending on whether this stabilization is carried out under anaerobic or aerobic conditions, this process is known as anaerobic or aerobic digestion. 32.8.09 SUBSTRATE is the term used to denote the organic matter or nutrients that are converted during biological treatment or that may be limiting in biological treatment. ( for example: carbonaceous organic matter in waste water is called the substrate that is converted during biological treatment.) processes are the biological treatment 32.8.10 SUSPENDED GROWTH processes in which the micro organisms responsible for the conversion of the organic matter or other constituents in the effluent to gases and cell tissue are maintained in suspension within the liquid. 32.8.11 ATTACHED GROWTH processes are the biological treatment processes in which the micro organisms responsible for the conversion of the organic matter or other constituents in the effluent are attached to some medium, such as rock, slag or specially designed ceramic or plastic materials. Attached growth processes are also known as: fixed film processes. 32.9

AEROBIC SUSPENDED GROWTH treatment

32.9.01 The processes are: 1) Activated sludge 2) Suspended growth nitrification process 3) Aerated lagoons (ponds) (as used in P.O.M's) 4) Aerobic digesters (also used in P.O.M's) 5) High rate oxidation ponds 32.9.02 AERATED LAGOONS: evolved from facultative stabilization ponds when surface aeration was installed to overcome the odours from organically overloaded ponds. Description: The aerated lagoon process is essentially the same as the conventional extended aeration activated sludge process (with Hydr. Retention Time = +> 10 days), except that an earthen basin is used for the "reactor" and the oxygen required by the process is supplied by surface or diffuser aerators. 135

Palm Oil Process The Principle & Operational Techniques Note: In an aerated lagoon all solids are maintained in suspension 32.9.03 AEROBIC DIGESTION Alternate method of treating organic sludge, produced from various treatment operations. Description: In conventional aerobic digestion, sludge is aerated for an extended period of time in an open, unheated tank using conventional air diffusers or surface aeration equipment. Either continuous or batch mode, with separate tank for decanting and/or concentration. 32.9.04 AEROBIC STABILIZATION PONDS In their simplest form, large - shallow earthen basins, used for the treatment by natural processes involving both algae and bacteria. Description: An aerobic stabilization pond contains bacteria (and/or algae) in suspension and aerobic conditions prevail throughout its depth. There are mainly two types: 1) Objective to maximize the production of algae (very shallow, limited to 6-18 inch depths) 2) Objective to maximize the amount of oxygen produced and pond depths up to 5 feet (1.6 m) are used. In both types, oxygen in addition to that produced by the algae, enters the liquid through atmospheric diffusion. For best results, contents must be mixed periodically, (pumps, surface aerators etc.) 32.9.05 AEROBIC PONDS Used for the treatment of high strength organic effluent, which also contain a high concentration of solids.

136

Palm Oil Process The Principle & Operational Techniques Typically an aerobic pond is a deep earthen pond, with appropriate inlet and outlet piping. To conserve heat energy and to maintain anaerobic conditions, anaerobic ponds have been constructed to depths of > 6 metres. The wastes added to the pond settle to the bottom. The partially clarified effluent is discharged to further treatment ponds. Usually these ponds are anaerobic throughout their entire depth, except for an extremely shallow surface zone. Stabilization is brought about by a combination of precipitation and anaerobic conversion of organic wastes to C.O.2, C.H.4, other gaseous end products, organic acids and cell tissues. B.O.D.5 conversion efficiency up to 70% are routinely obtainable. Under optimum operating conditions removal efficiency up to 85% is possible. 32.9.06 FACULTATIVE PONDS Ponds in which the stabilization of wastes is brought about by a combination of aerobic, anaerobic and facultative bacteria, are known as facultative (aerobic -anaerobic) stabilization ponds. Description: Basically three zones exist in facultative ponds: 1) A surface zone, where aerobic bacteria and algae exist in a symbiotic relationship. 2) An intermediate zone that is partly aerobic and partly anaerobic, in which the decomposition of organic wastes is carried out by facultative bacteria. 3) An anaerobic bottom zone in which accumulated solids are actively decomposed by anaerobic bacteria. In practice, oxygen is maintained in the upper layer by the presence of algae, or by the use of surface aerators (in which case there are no algae required) The advantage of surface aeration is that a higher organic load can be applied. However, the organic load MUST NOT EXCEED the amount of oxygen 137

Palm Oil Process The Principle & Operational Techniques that can be supplied by the aerators without completely mixing the ponds contents, or the benefits from anaerobic decomposition will be lost. 32.9.07 TERTIARY MATURATION PONDS Low rate stabilization ponds, designed to provide secondary effluent "polishing" and seasonal nitrification. The biological mechanisms involved are similar to the other aerobic suspended growth processes. Operationally the residual biological solids are endogenously respired and ammonia is converted to nitrate using the oxygen supplied from surface aerators (and where exist from algae) Minimum 20 days H.R.T to provide for complete endogenous respiration of the residual solids. To maintain aerobic conditions, the applied loading must be kept quite low. The efficiency of low rate ponds decreases with decreasing waste water temperature (all biological Nitrification systems suffer from these phenomena) To provide a reliable nitrified effluent that is low in B.O.D. 5 and suspended solids, an efficient and reliable effluent solids removal process will be required. 32.9.08 SOLIDS SEPARATION Probably the most important aspect of biological effluent treatment is the design of the facilities to separate The biological solids from the treated waste water; for it is axiomatic that if the solids cannot be separated and returned to the aeration tank, the activated sludge process will not function properly. 32.10

The control methods and technology

32.10.1 The choice of an appropriate effluent system depends on various factors, such as the characteristics of the effluent, (physical, chemical and biological), the local environment, the degree of treatment before disposal stipulated by the regulating authorities and the economic considerations.

138

Palm Oil Process The Principle & Operational Techniques 32.10.2 Since C.P.O. factories are usually located in the more remote areas, high levels of skill for the operation and maintenance are often not available or achievable and the preferred choice of suitable treatment must take this into account. C.P.O. factory liquid effluent can be said to be composed off: i) Clarification wastes (± 60 - 70 %) ii) Sterilizer condensate (± 30 - 40%) iii) Other liquid wastes (± 5%) A correctly operated C.P.O. factory, under proper control, will typically produce about 2 to 2.5 tonne of effluent for every ton of C.P.O. produced. This figure varies according to the design, i.e. conventional continuous settling versus decanter systems etc., but is seldom lower than that suggested above. 32.10.3 The effluent produced has typically a B.O.D. value of between 20,000 and 25,000 mg/litre, but is not (or very seldom) toxic. The effluent of the clarification process of the C.P.O. is the most difficult to treat, due to its viscosity caused by a high proportion of suspended solids. 32.11

Treatment types

32.11.1 A number of systems have been developed over the past decade, to treat this effluent. Most are biological processes, dictated by the bio degradable nature of the effluent. The processes are usually combinations of anaerobic and aerobic processes. 32.11.2 Before these processes, the proper screening, filtering and centrifuging to reduce the suspended solids as much as possible must be maintained, so that the "final" effluent to be treated has the lowest possible quantity of suspended solids. 32.11.3 Appropriate methods include the following: a) Anaerobic / facultative ponding b) Anaerobic / extended aeration ponding c) Anaerobic tank digestion / extended aeration ponding 139

Palm Oil Process The Principle & Operational Techniques d) Anaerobic treatment followed by land application All methods must have the anaerobic stage, for the following reasons: i)

High destruction efficiency (including lipids and pathogenic bacteria) ii) Lower sludge production iii) Low power requirement iv) Possible recovery / utilization of the methane gas produced. 32.11.4 Anaerobic processes can be either thermophilic or mesophyllic. Thermophilic reactions are generally more efficient but are highly sensitive to temperature variations (hence mainly used in "tank type digesters") Owing to the above, the processes that take place in anaerobic ponds are usually mesophyllic. 32.12

The anaerobic / facultative pond system

32.12.1 Essentially the components are: : the de - oiling tank : the acidification ponds : the methogenic ponds : the facultative ponds : the sand beds 32.12.2 The raw effluent firstly enters the (usually concrete) de - oiling tank, which should have a Hydraulic Retention Time (H.R.T.) of ±1.5 days. Free oil is trapped and some solids settle out. The effluent is homogenized, cooled to a degree and flows to the anaerobic ponds. 32.13.1 The anaerobic ponds have two distinct phases: : the acidification phase : the methogenic phase By keeping these processes separated, by using two separate ponds, the optimum individual environment for both the acidification and the methogenic reactions are ensured.

140

Palm Oil Process The Principle & Operational Techniques 32.13.2 The acidification ponds are two ponds in series (with 2 days H.R.T. each), where the bacteria convert organic components into volatile fatty acids, which lower the pH of the liquor. Two ponds in series are used in order to restrict the bonded oil released to the first pond. The raw effluent is mixed with liquor from the primary anaerobic ponds (of the methogenic phase), this cools the effluent further, decreases the pH further and facilitates "seeding" (ratio 1:1) 32.13.3 The methogenic phase takes place in two ponds in series, with a typical H.R.T. of 30 and 15 days respectively. Here the volatile fatty acids are converted to methane, Co2 and other gases. 32.13.4 The partially treated liquor is then aerated in facultative ponds in series, with a total H.R.T. of 16 days, before being allowed to flow to the final discharge. 32.13.5 The sludge solids will build up in the anaerobic ponds. When this is de-watered on sand beds a cake can be recovered which can be utilized as plant nutrient. 32.13.6 This type of system is generally good with a final B.O.D. level well below 200 mg per litre and will handle "shock loads" from the factory. Other systems have been developed, basically similar to the one described above, but with different features (see sketch 2)i.e.: : de-oiling as part of the first acidification pond : longer retention times in the anaerobic ponds ( 70 days) (the longer period tends to even out fluctuations in loading rates and inefficiencies caused by poor maintenance of the system). Here also B.O.D. levels can be well below 100 mg/litre. 32.14

The Anaerobic / Extended aeration ponding system

32.14.1 This system is similar to that described under 32.13 above, but here the facultative ponds are replaced by extended aeration lagoons. The reason for this is that the facultative ponds with their retention 141

Palm Oil Process The Principle & Operational Techniques time of 12 to 16 days and shallow depth (less than 1.5 metre) occupy rather large areas. An aerated lagoon, with its greater depth will cover substantially less area, retention time however will increase to 20 days. 32.14.2 The extra, mechanical, aerators will increase the capital costs, the recurring maintenance costs and the power requirements. Unlike the anaerobic/facultative ponding system, this system is sensitive to shock loads and the oxygen transfer in the aerated lagoon. The aerated liquor needs to be settled in an aerobic sedimentation tank or pond with at least a one day retention prior to final discharge. 32.15

Anaerobic Tank Digestion/Extended aeration system

32.15.1 This system has tank digesters, coupled with aerated lagoons. The closed type is suitable for tapping the bio gas produced which can be used as an energy source. Tank digesters are capital intensive, but do have a number of advantages; i.e.: a) compact, thus requiring little land area b) High loading rates and shorter retention time c) Easier for corrective measures (and sampling) d) Bio-gas production as energy source e) good mixing of (tank)contents possible 32.15.2 Tank digestion may be mesophyllic or thermophilic, the latter generally produces better digestion conditions. The anaerobic liquor discharged from the digester does require further treatment.( see sketch 3 & 4) 32.15.3 The raw effluent is acidified with anaerobic liquor from the tank digester, (H.R.T.= 1 day ), ratio 1:1 (by volume) The acidified effluent is then fed to a (mild) steel tank digester. Typical reduction in B.O.D. levels are 90 to 95 %. The tank contents are mixed or stirred with a "gas mixing" system. Gas mixing requires about 12% of the power required by a mechanical stirring device and costs about 25% less as there are no moving parts. 142

Palm Oil Process The Principle & Operational Techniques Compressed bio gas from the digester process is directed to an emitter in the digester which allows escape of gas through a draught tube. The motion of the gas bubbles sets up a circulating current in the effluent that helps mixing. H.R.T. for these digesters is ±10 days. (Open tank digesters are not stirred, typical retention time +/- 20 days) 32.15.4 In un stirred tank digesters the solids sink/settle to the bottom and are drawn off. Typical solids reduction is about 40%. The anaerobic liquor is then decanted to an anaerobic settling tank that further settles out solids (60 to 80% ) 32.15.5 The supernatant is then fed to an extended lagoon ( typical H.R.T.= 20 days). The anaerobic liquor is settled for one day in an anaerobic settling tank before allowing final discharge. Final B.O.D. of < 100 mg / litre are possible, however variations in effluent feed rates, B.O.D. input levels and suspended solids from the tank digesters and the settling efficiency of the anaerobic settling tank all affect the final B.O.D. level. 32.15.6 The settled solids are rich in nutrients and can be utilized as fertilizers. The final discharge from these type of systems has been used to recycle to the factory as process water.

143

Palm Oil Process The Principle & Operational Techniques Typical performance of the tank digester/aeration pond system: (Parameters all except pH in mg/l) RAW EFFLUENT

32.16

FINAL DISCHARGE

REDUCTION %

pH

4.8

8.1

N/A

B.O.D.

30800

120

99.6

C.O.D.

76090

1460

98.1

TOTAL SOLIDS

57030

6720

88.2

SUSPENDED SOLIDS

27920

1060

96.2

VOLATILE SOLIDS

43490

2160

95.0

OIL , GREASE

10450

30

99.7

NH3 - NITROGEN

50

3

94.0

TOTAL NITROGEN

1030

100

90.3

Land application of partially treated effluent.

32.16.1 Because of its rich nutrient content, the anaerobic liquor can be utilized as a fertilizer resource in the oil palm plantations. Raw effluent can also be used, but the high B.O.D. levels usually create an unpleasant odour and a fly / insect nuisance. The possibility of surface run off during heavy rain periods contaminating existing fresh water streams can also not be discounted. 32.16.2 Partially treated anaerobic liquor, with B.O.D. level not more than 5000 mg/l is suitable for land application and may also at the same allow the production and utilization of bio gas. 32.16.3 Partial digestion does not appreciably change the nutrient contents of the effluent, (which is related mainly to the nitrogen content) but complex organic molecules are broken down and are thus easier to be assimilated by the plants.

144

Palm Oil Process The Principle & Operational Techniques 32.17

Methods of land application

32.17.1 Although the physical land application is generally outside of the area of responsibility of the technical mill staff, a basic knowledge of the methods used to apply partially or fully digested effluent to the "fields" enhances the overall appreciation of the total effluent control system. There are a number of different methods to distribute this (still liquid) effluent, i.e.: I ) Fixed spray lines, moveable spray lines with sprinkler system In fixed spray line sprinkler systems the effluent is pumped through buried pipe lines direct to the sprinklers. Sprinklers are generally fixed every third row of palm trees and at about 27 metres intervals. Capital costs are high and maintenance costs are high. In moveable spray line sprinkler systems the basic principle is the same, but as a result of using moveable lines, the capital costs are substantially lower. Fast lock, clip lock type couplings facilitate the removal of the spray lines, at which time clogging etc. can be detected and cleared. II ) Flat beds Flat, bunded beds constructed between rows of palms are connected by channels which run from the top end to the bottom end of the slopes. Effluent is pumped to the top and allowed to run down the channels and each bunded bed is filled to a shallow depth, starting with the lowest. As each bed is filled, the feed is closed and directed to another channel. III) Furrows Here the effluent is pumped to high points and allowed to drain down the slopes in furrows of about 20 to 30 cm deep and about 30 cm wide. The velocity of the flow should be slow enough to allow percolation into the soil. Zig-Zag configuration on steeper slopes 145

Palm Oil Process The Principle & Operational Techniques reduces the flow velocity and prevents erosion. The zigzag configuration will cause problems of uneven distribution, silting is also common. IV) Percolating trenches or pits Trenches and pits dug along the slopes are usually the silt pits dug to contain the sediments transported by surface erosion. The effluent is discharged into these pits and allowed to percolate into the soil. 32.17.2 The rate of application is decided and affected by various factors, i.e.: a) Characteristic of effluent, the concentration of solids (size of solids as well) The presence of "large" solids will frequently block or clog sprinkler nozzles. b) Type of vegetation between rows of palms c) Soil characteristics, the acidity, the porosity, normal water table etc. Over application may result in anaerobic conditions due to the formation of an impervious layer of organic matter on the soil surface. d) Age of palms, since palms of different age require different rates of application, which are usually determined by experimentation. 32.18

Effects of the application of digested effluent

32.18.1 Although the effects vary from place to place and the optimum for a particular plantation area is largely determined by experimentation, on average the yield of oil palm increases with the use of digested effluent. 32.18.2 The nutrient value of the soil improves, especially the phosphorus, the potassium and the magnesium values. The resulting leaf growth has proved to have increased values of nitrogen, phosphorus, calcium and magnesium, all assisting in a higher F.F.B. production per palm. The effect on underground water has been shown to be negligible and surface drainage is not polluted, provided the application method and the application rates are controlled. 146

Palm Oil Process The Principle & Operational Techniques CPO MILL EFFLUENT Palm Oil Mill Effluent, POME, has a high organic polluting load and if released untreated into natural watercourses would result in a severe depletion of the dissolved oxygen level in the stream or water course. The organic pollution load is measured by the Biological Oxygen Demand, BOD of the effluent. By definition BOD is the amount of oxygen required for biological oxidation of waste over a stated period of time. (which in the tropical regions is usually interpreted as 3 days at 30 deg. Celsius) The higher the BOD load, the greater will be the polluting effect on the receiving water course. Depending on the frequency of discharge and the type / size of the water course it could lead to anaerobic conditions causing the death of the aerobic eco system and the destruction if the water course in terms of social and amenity value. Acceptable levels vary from country to country and should be checked with the authorities, but is almost always expressed in terms of the BOD level. (BOD levels for direct land application are usually much higher, up to 50 times as high) Treatment to an acceptable level of BOD before discharge is therefore required. ANAEROBIC DIGESTION: The cellulosic nature, high BOD and high temperature of POME practically precludes the effective use of aerobic methods of biological treatment. Anaerobic treatment, because of its ability to utilize combined oxygen and not dissolved oxygen is ideally suited to the treatment of high organic strength POME. Also, because of the use of combined oxygen, the higher temperatures, as high as 60 deg.C are not harmful but are actually beneficial in stimulating the rapid growth of the anaerobic microorganisms. This fact, coupled with the very high rate of decomposition of oils and greases and cellulosic solids by a number of anaerobic activities, make it very attractive as a first treatment for POME. 147

Palm Oil Process The Principle & Operational Techniques The biochemistry of Anaerobic digestion is a two stage process, with both stages occurring simultaneously and in balance with each other. The first or acidogenic stage is dominated by a diverse group of facultative and anaerobic bacteria which have the ability to hydrolyze the POME constituents to soluble, less complex organic mixtures which are subsequently fermented to volatile acids for the most part , whilst some carbon dioxide and hydrogen gas is also produced. Very little COD stabilization occurs at this stage as the only COD leaving the system is the small amount of hydrogen gas that is formed and escapes. The second or methanogenic stage of the anaerobic digestion is dominated by a diverse group of strictly anaerobic bacteria which will oxidize hydrogen and reduce carbon to form methane and water, and /or ferment volatile acids to form methane and carbon dioxide. 4H2 + CO2 CH3OOH

forms CH4 + 2 H2O forms CH4 + CO2

COD stabilization which occurs as methane and is insoluble in water is formed and leaves the system Operating requirements: Compared with the acidogenic bacteria the methanogenic ones are particularly slow growing and sensitive to changes in their environment. Therefore conditions have to be created that are favorable to methanogenic bacteria. pH, temperature and toxic materials have the greatest effect on the micro organisms rate of growth and on its metabolic activities. The optimum operating pH for the anaerobic biological process is around the neutral mark, 7. pH values below 6 and above 8 are not favorable and may even be toxic to the methanogens. The digestion process can be carried out at either the mesophilic range of 25 - 45 deg.C or the thermophilic range of 45 - 85 deg.C. A number of substances, such as chlorinated hydro carbons, heavy metals, synthetic detergents etc., have been reported to have an inhibitory effect on the process. 148

Palm Oil Process The Principle & Operational Techniques POME does not normally contain these substances, or if they are present they are not present at inhibitory levels. The major buffering in an anaerobic digestion is the CO2 - HCO3 system. During the digestion process bicarbonate alkalinity is formed from ammonia which reacts with H2O and CO2. The ammonia is produced through the de-amination of the protein present in the POME and the bicarbonate alkalinity serves to prevent rapid changes in the pH and in a properly operating system treating POME it should be > 2,000 mg/l as CaCO3. In a well balanced system the volatile acids (VA) produced during the first stage of the digestion are utilized as a major substrate by the methane producers without accumulation of the acids in the system. Under this normal digesting condition the VA concentration is usually less then (or about) 400 mg/l expressed as acetic acid. However when the digestion process becomes overloaded, the slower methanogens cannot cope with the amount of VA produced. (popularly stated, the mixture turns 'sour') Depending on the buffering capacity of the system and the extend of the overloading the accumulation of the VA may deplete the buffering capacity of the digestion process totally, leading to a depression of the Ph to such an extent as to impair the activities of the more sensitive methanogens and the whole process turns "sour'. pH by itself is not a good control parameter as the pH does not decrease significantly in an adequately buffered digestion system until the system is already seriously affected. The best control parameter to use is the VA concentration and this should be used along with the pH and the alkalinity. These three parameters should be determined daily (preferably before feeding of the system starts) Any sharp increase over the normal VA concentration of the system is an indication of an impending failure and this should be immediately followed by feed reduction or even total stoppage. For POME the normal range is as follows: pH Alkalinity VA

149

= or > 7 = > 2,000 mg/l = < 400 mg/l

Palm Oil Process The Principle & Operational Techniques In some cases one may have to add neutralizing agents such as NaHCO3 to arrest the pH falling further to a level where the methanogens are inactivated. Basic criteria for anaerobic digestion systems: The most commonly used for POME is the Anaerobic lagoon type treatment, although the conventional tank type digesters are also used. Anaerobic contact, anaerobic filtering and anaerobic sludge blanket type are sometimes used in the municipal waste water treatment systems. Anaerobic lagoon: This is basically a large holding unit, usually in an earthen basin. Mixing of the lagoon contents is not provided and the retention time is long (minimal 40 days) in order to allow degradation of the POME to take place, gas to be produced and released and solids to settle down. Lagoons are always made as deep as possible (min. 3 - 4 meter) in order to minimize surface area and hence reduce the oxygen transfer from the atmosphere to the anaerobic system. Anaerobic lagoons are normally subject to low organic loading of 0.65 1.3 kg VS/cubic meter lagoon capacity per day. The advantages are generally the 'ease' of construction and the 'low' capital cost. The disadvantages are the long retention time; thus requires a large area, the need to de-sludge the lagoon to maintain its effective volume, the extensive need to monitor over a large area, requiring manpower and time. The system does not allow the capture and storage of any bio gas produced. Retention time for anaerobic treatment of POME varies from 20 to 100 days, depending on the degree of treatment wanted and the variability of the 'influent' feed. Recycling of the anaerobically digested overflow by mixing with the raw effluent will improve the pH of the influent feed into the anaerobic 150

Palm Oil Process The Principle & Operational Techniques pond and depletes the oxygen content in the influent, which is desirable for anaerobic digestion. The use of anaerobic digestion alone would not be able to meet the standards as required or as stipulated, further treatment of the effluent from the anaerobic ponds is necessary and this is usually done in facultative ponds, where sufficient oxygenation to the water is introduced. The effluent after sedimentation in these ponds is allowed to discharge into the drains river, stream etc. Ponds should be located there where there is minimum effect on the surrounding environment and habitation. The required size of the ponds can be calculated from a number of given factors and flow rates, such as: Effluent ex sterilization station Effluent ex clarification station Effluent ex hydrocyclone plant Spillages , wash water etc

= ± 0.15 m3/tonne FFB = ± 0.45 m3/tonne FFB = ± 0.05 m3/tonne FFB = ± 0.10 m3/tonne FFB ——————————— = 0.75 m3/tonne FFB

The above example is about correct for a conventional, static tank type clarification system operated palm oil mill, with dynamic type clarification it can be reduced to about 0,45 m3/tonne FFB. For a 60 tph factory @ 0.75 tonne effluent/tonne FFB, the effluent to be handled in a 20 hour work day : = 20 x 60 x 0.75 = 900 tonnes/day. The BOD in the raw effluent can be assumed to be around 25,000 to 30,000 mg/l. For calculation the worst should be prepared for, i.e.the maximum BOD load per day: = 900 x 30,000/1000 = 27,000 kg/day. At a maximum loading of 0.4 kg BOD/m3, the effective pond volume required would be 27,000 kg BOD/day divided by 0.4 kg BOD/m3 = approximately 67,500 cubic meter.

151

Palm Oil Process The Principle & Operational Techniques Allowing for a 20 % silting up factor, and realizing that ponds should not be filled to their maximum level in order to prevent unexpected overflows etc., the actual pond capacity should be around 67,500 x 1.3 = 87,750 cubic meter. The initial minimum retention time in these primary ponds will thus be 87,750 cubic meter divided by 900 cubic meters/day = about 97.5 days, which will steadily reduce as the solids built up in the ponds and the effective volume reduces. The effluent leaving the anaerobic ponds is expected to have a BOD of between 500 and 1000 mg/l. For the anaerobic maturity pond(s) at 900 cubic meter/day and a maximum loading of 0.1 kg BOD/m3 , the effective pond capacity required will be (900 : 0.1) x 1.2 = 10,800 cubic meters, or equivalent to about 12 days retention time. The effluent leaving from this treatment should have a BOD between 200 and 500 mg/l. Facultative ponds: The total maximum BOD load/day will be approximately: (900 x 500) : 1000 = 450 kg/day. At a maximum loading of 0.3 kg BOD/cubic meter, the effective pond capacity required for a 12 day retention will be approximately 21,500 cubic meter. These should be shallow ponds with an operating depth of about 1.25 meter only , a total depth of about 1.75 meter should be sufficient. The effluent leaving these ponds is expected to have a BOD of less than 100 mg/l. Anaerobic "Conventional" system: The tank type digester can be "low-rate" or "high-rate" designs. In the low-rate type the digester contents are not mixed, thus there is stratification in the digester. The solids retention time (SRT) is only partially dependent on the hydraulic loading, the process operates at a long hydraulic retention time (HRT) of 30 to 60 days

152

Palm Oil Process The Principle & Operational Techniques The high-rate digester is a completely mixed digester where the SRT equals the HRT. Mixing of the contents is either by a mechanical stirrer or by gas recirculation Power requirements are low (±1.8 Kw/cu.m capacity) with a bio gas recirculation rate of about 2 cu.m/min. The advantages of a high rate digester are that the formation of a scum layer in the digester is prevented. Uncontrolled scum formation will lead to an appreciable reduction of the digester's capacity and will affect the sampling results if samples are drawn quite close to the surface. Thermal stratification in the digester is avoided, particularly when the POME influent temperature is kept around 70 - 80 deg.C. There will be good contact between substrates and micro organisms and a shorter retention time, i.e. a smaller digester capacity, is required. Solids in the digester are kept to a minimum, as uncontrolled solids settlement will reduce the digester capacity. The advantage of the high rate is the ability to operate on low HRT (about 10 days) with high organic loading of up to 4.8 kg VS/cu.m digester capacity / day. It requires a much smaller area (about 20 % of the lagoon type) and allows the capture and harnessing of the bio gas produced. The initial capital cost however is high as the digester's construction is usually in mild steel with the internal surfaces in contact with bio gas sand blasted and coated with epoxy. Unless there is an economical application of the bio gas produced, or other compelling external reasons, the system is not commonly used for the treatment of POME Common operational problems: The successful operation of an anaerobic system requires a basic understanding of the process, its limitations and an effective monitoring system from which one can predict (and thus can prevent) impending failures. Unfortunately, it is often seen by otherwise responsible mill engineers and staff as a nuisance and "the less they know about it the better it suits them". 153

Palm Oil Process The Principle & Operational Techniques POME is ideally suited to anaerobic treatment: 1) it is available at 70 - 80 deg.C and hence can be digested "as is" at the thermophilic range and temperatures as high as 55 deg.C can be achieved without any external, additional heating. 2) the high buffering capacity in the system allows digestion of the POME without neutralizing prior to feeding. 3) no toxic substances are present in inhibitory levels to the microorganisms. Despite this , digester failures do occur and can almost always be attributed to overloading of the anaerobic system, mainly arising from: a) overfeeding; this could be due to putting too much effluent into the pond (hydraulic loading) or the organic content of the effluent is too high (organic loading) b) reduction in operating capacity, either from lowering of the operating levels, or from sludge built up. The use of a reliable flow meter, or a reliable basculator should help to prevent the pumping of too much effluent into the system. A difference must be made between hydraulic loading and organic loading. HRT is obtained by dividing the effective digester capacity (in cub.m) by the actual feed input/day (cub.m/day). Whilst HRT can be maintained by ensuring a constant feed rate, the organic loading may not be so easily maintained as this is mostly affected by oil present in the POME. Example: digester capacity feed to digester TVS in POME oil content HRT organic loading

: 4200 cub.m : 420 cub.m : 45,000 mg/l : 10,000 mg/l = 4200/420 = 10 days = 420 x 45/4200 = 4.5 kg VS/cub.m/day

if the oil content increases to 20,000 mg/l: TVS : 55,000 mg/l HRT = 10 days organic loading = 5.5 kg VS/cub.m/day In other words, in order to maintain the organic loading of 4.5 kg, the 154

Palm Oil Process The Principle & Operational Techniques feed to the digester must be reduced to 4.5 x 4200/5.5 = 343 cub.m/day, a reduction of 18% of the designed maximum HRT. Characteristics of digested effluent: With the high rate digester system, the BOD removal can be as high as 95 % and to obtain the final effluent quality suitable to return to any water course discharge, the digested effluent can be settled with the resulting supernatant going into an aerobic system. The underflow of the settling tank can be recycled to the digester. Digested effluent is rich in N, P and K and can be used in the estates to supplement or replace the normally used inorganic fertilizers, the fertilizer value is approximately: (for 60 tph mill, at ± 20 hrs/day) Ammonium Sulphate (21 % N) Rock Phosphate (36 % P2O5 ) Muriate of Potash ( 60 % K2O) Kieserite ( 26 % MG O)

2.00 tonne/day 0.75 tonne/day 2.25 tonne/day 2.25 tonne/day

The high rate digester also produces approximately 25 cubic meter bio gas with a calorific value of approximately 22,400 KJ/cubic meter, from 1 cubic meter of POME digested. The direct use of the bio gas as a heat source is probably the most economical way of using it.

EFFLUENT FROM CPO MILLS BEFORE TREATMENT

155

TEMPERATURE

70 - 80OC

pH

4

VOLATILE ACIDS

1,000

COD

80,000

BOD

30,000

TOTAL SOLIDS (TS)

60,000

TOTAL VOLATILE SOLIDS (TVS)

45,000

SUSPENDED SOLIDS

38,000

AMMONIAL NITROGEN (NH3-N)

40

TOTAL KJELDAHL NITROGEN (TKN)

900

PHOSPHORUS

200

POTASSIUM

2,000

MAGNESIUM

600

Palm Oil Process The Principle & Operational Techniques AFTER TREATMENT DISCHARGE TO WATER COURSE

LAND APPLICATION

BOD

100-5000

SUSPENDED SLOIDS

400 N/A

OIL & GREASE

50

AMMONIACAL NITROGEN

150 (1)

TOTAL NITROGEN

200 (2)

pH

5-9

TEMPERATURE

45OC

CHARACTERISTICS OF DIGESTED POME HIGH DIGESTER RATE TEMPERATURE

43

pH

7.15

VOLATILE ACID

265

ALKALINITY

2,300

BOD

1,900

SUSPENDED SOLIDS

3,725

AMMONIACAL NITROGEN

55

TOTAL KJELDAHL NITROGEN

175

OIL & GREASE

175

FERTILIZER VALUE OF DIGESTED POME EXAMPLE FOR 60 TON PER HOUR FACTORY OUTPUT FERTILIZER SUBSTITUTE

DIRECT LAND

HIGH RATE DIGESTER

AMMONIUM SULPHATE (21% N)

0.65

1.92

ROCK PHOSPHATE (36% P2O5)

0.17

0.62

MURIATE OF POTASH (60% K2O)

1.55

2.18

KIESERITE (26 % MgO)

1.05

2.10

NOTES: Items (1) and (2) measured from filtered samples All values in mg/l, exept pH.

156

Palm Oil Process The Principle & Operational Techniques NUTRIENT CONTENTS OF OIL PALM WASTE PRODUCTS POME (Palm Oil Mill Effluent): (at 5% dry matter) From literature

Own analisis

On average per 1000 liter

%

%

In kg

N

2.4

N

1.7

N

1

P

0.3

P

0.35

P

0.17

K

4.8

K

2.7

K

1.9

Mg

1.4

Mg

0.58

Mg

0.5

Ca

0.8

Ca

1.1

Ca

0.5

S

0.24

S

0.12

Cl

1.0

Cl

0.5

Dried decanter sludge (% on dry matter) N

2.3

P

0.2

K

0.7

Mg

0.3

Ca

2.9

S

0.2

Cl

0.1

EMPTY BUNCHES as bunch ash (%)

157

as empty bunches

as empty bunches

(70% moisture, 30 % dry matter) (% on dry matter)

(in kg per 1000 kg Empty Bunches)

N

0.05

N

0.79

N

2.4 kg

P

1.5

P

0.08

P

0.24 kg

K

30.0

K

2.0

K

6.0 kg

Mg

3.0

Mg

0.12

Mg

0.35 kg

Ca

4.0

Ca

0.25

Ca

0.75 kg

S

0.08

S

0.24 kg

Cl

0.21

Cl

0.63 kg

Mn

300 ppm

B

120 ppm

Palm Oil Process The Principle & Operational Techniques

Chapter #33 AIR POLLUTION 33.1

Boiler smoke The gases emitted from the chimney stacks of the boilers and the incinerators of C.P.O. factories contain particulates of condensed tar droplets and soot and other contaminations from 20 to 100 microns in size.

33.1.1 Boiler smoke is dark in colour due to the soot resulting from incomplete combustion of the mixture of fibre and shells used as fuel. The control of this smoke emission depends largely on the type (and the age) of the boiler(s) in use. 33.1.2 Some form of control over the combustion conditions may be achieved by efforts to maintain as much as possible a "steady state" condition. The main options for control measures are: i)

Adequate and accurate instrumentation. Indicative instruments, such as steam pressure gauges, air pressure gauges, CO2 meters, smoke density monitors etc. should be installed and maintained in a functional condition. These will indicate if complete, or as near as possible complete combustion is taking place. Optimum levels of CO2, compatible with "steady state" operations are about 15 to 20%.

ii) Automated control of fuel feed rates. The steam demand by the factory varies and thus maintaining a "steady state" condition compatible with the fluctuating demand requires continuous control. A closed loop control of the fuel feed rate and air supply can 158

Palm Oil Process The Principle & Operational Techniques assist or ensure a steady state combustion in tandem with the steam demand. iii) Modifications to boilers to improve the combustion conditions can include: a) prevention of (secondary) air leaks into the furnace (for instance through furnace doors) b) increasing the air volumes by using larger capacity draught fans c) promoting secondary air flow in furnace by directional nozzles d) mechanical fuel feed control e) increased chimney stack height to facilitate dispersion. 33.1.3 The control of particulates in the boiler smoke can be effected by baffle plates and secondary nozzles blowing down in the furnace. Dust collectors can be installed to cope with the particular conditions such as: - size of particles to be removed - required efficiency - flow rate of flue gases - composition of flue gases Dust collectors can be mechanical (cyclones) or cloth collectors (bag filters) or liquid scrubbers. 33.1.04 Cyclones may be single stage or multi stage. The single stage has an efficiency factor of about 40 to 50%, whilst the multistage can be as high as 85%. Cyclones require gas velocities of 7 to 20 metres per second in order to operate properly. Some cyclones have a water feed at the inlet (irrigated cyclone) to further assist in the collection of fine dust particles. 33.1.5 Bag filters simply trap the particles in the fabric when flue gases are drawn through the bag. The cost of bags and the maintenance cost is usually prohibitive and unless very strict pollution control measures are the norm, not generally used.

159

Palm Oil Process The Principle & Operational Techniques 33.1.6 Liquid scrubbers are quite effective particle removers, but are also quite expensive, both in capital expense and maintenance costs. Economic considerations and particular local circumstances may be the deciding factor. 33.2

Smoke from incinerators for Empty Fruit Bunches

33.2.1 The control of smoke/particulate emission from incinerator stacks can also be improved by improving combustion efficiencies with regulated feed rates. 33.2.2 The nature of the operation of incinerators ,i.e. the slow and "low" temperature burning also results in low gas exit velocity and precludes the use of dust collection equipment . 33.2.3 The "stack plume" is high in moisture content and thus has little buoyancy, therefore aerial dispersion is usually minimal. Visual observation of the colour of the smoke emitted from the stack can usually give a fair indication of the combustion condition. 33.2.04 The Ringelmann smoke charts may be used to determine either the increase or decrease in combustion efficiency by comparing the relative blackness of the smoke against these charts. Since each chart (6 in total) indicates a change of 20 % in the observation, an estimate can be made of the altered combustion condition and controls adjusted to achieve optimum conditions.

160

Palm Oil Process The Principle & Operational Techniques

SECTION #5 THE FACTORY STEAM & ELECTRICITY GENERATION MONITORING & EVALUTION

161

Palm Oil Process The Principle & Operational Techniques

Chapter #34 GENERATION OF STEAM AND ELECTRICITY 34.1

General boiler water information.

34.1.01 The most common components of boiler water deposits are: CALCIUM PHOSPHATE; CALCIUM CARBONATE (in low pressure boilers). MAGNESIUM HYDROXIDE; MAGNESIUM SILICATE; various forms of IRON OXIDE; SILICA (absorbed on previous mentioned precipitates and ALUMINA. 34.1.02 EXPECTED AVERAGE COMPOSITION OF BOILER SLUDGE

162

CONSTITUENT

COAGULATION TREATMENT

PO4 RESIDUAL TREATMENT

Calcium carbonate

HIGH

USUALLY < 5%

Calcium phosphate

USUALLY < 15%

HIGH

Calcium silicate

USUALLY < 3%

TRACE OR NIL

Calcium sulphate

NIL

NIL

Calcium hydroxide

NIL

NIL

Magnesium phosphate

NIL

USUALLY < 5% (except in H.P. boilers)

Magnesium hydroxide

MODERATE

MODERATE

Magnesium silicate

MODERATE

MODERATE

Silica

USUALLY < 10%

USUALLY < 10%

Alumina

< 10%

USUALLY < 10%

Oil

NONE

NONE

Iron oxide

USUALLY < 5%

USUALLY < 5% (except in high purity feed water)

Sodium salts

USUALLY < 1.5%

USUALLY < 1.5%

Copper

TRACE

USUALLY LOW

Other metals

TRACE

LOW

Loss on ignition

USUALLY < 5%

USUALLY 8 - 12 % (except in very pure feed water)

Palm Oil Process The Principle & Operational Techniques 34.1.03 If phosphate salts are used to treat the boiler water, calcium will preferentially precipitate as the phosphate before precipitation as the carbonate and calcium phosphate becomes the most prominent feature of the deposit. At the high temperature found in boilers, deposits are a serious problem causing poor heat transfer and potential tube failures. In low pressure boilers with a low heat transfer deposits may build up to a point where they completely occlude the boiler tube. Normally , water circulating through the tubes conduct the heat away from the metal, preventing the tube from reaching the stage whereby the metal structure weakens. 34.1.04 Deposits insulate the tube, reducing the rate at which this heat can be removed, which leads to overheating and eventual tube failure. If the deposit is not thick enough to cause such a failure, it can still cause a substantial loss in efficiency and disruption of the heat transfer load in other sections of the boiler. Deposits can be SCALE, precipitated in-situ on a heated surface, or previously precipitated chemicals, often in the form of a sludge. These "drop out" of the water in low velocity areas (circulating velocity), compacting to form a dense agglomerate similar to scale. but retaining the features of the original precipitate. 34.1.05 The second major water related boiler problem is CORROSION, the most common being the attack by oxygen. This occurs in virtually every part of the system, from tanks, pipelines, valves, boiler condensate lines etc., every where oxygen is present. Oxygen attack is speeded up by high temperatures and by a low pH of the water. There is also an alkali attack , corrosion mainly in high pressure boilers, where caustic can concentrate in a local area of steam bubble formation because of the presence of porous deposits. 34.1.06 The third major problem is the carry over from the boiler into the steam system. This may be a mechanical effect, such as boiler water spraying around a broken baffle, it may be due to the volatility of certain boiler water salts (such as silica and sodium compounds) or may be caused by foaming. 163

Palm Oil Process The Principle & Operational Techniques 34.1.07 Carry over is most often a mechanical problem and the chemicals found in the steam are those originally present in the boiler water, plus the volatile components that distil from the boiler, even in the absence of spray. There are three basic means for keeping these major problems under control: 1) EXTERNAL TREATMENT OF THE WATER , make up, condensate or both, BEFORE it enters the boiler, to reduce or eliminate chemicals (such as hardness or silica) gases or solids. (see 34.2 here under) 2) INTERNAL TREATMENT OF THE BOILER (FEED) WATER, boiler water, steam or condensate, with corrective chemicals. 3) BLOW DOWN, Control of the concentration of chemicals in the boiler water by "bleeding" of a portion of the water in the boiler. 34.2

EXTERNAL TREATMENT.

34.2.01 Broad classification, the aim is to control: a) suspended solids b) hardness c) alkalinity d) silica e) total dissolved solids f) organic matter g) gases a) Suspended Solids The removal is accomplished by coagulation/flocculation, filtration or precipitation. Other processes (except "direct reaction") usually require prior removal of solids Example: Ion exchange water should contain less than 10 mg/l suspended solids to avoid fouling of the exchanger and cause operating problems.

164

Palm Oil Process The Principle & Operational Techniques b) Hardness A number of unit operations remove calcium and magnesium from water, summarized in the table below: Impurity to be remove d

Direct addition (note 1)

Coagulatio n flocculation

Solids liquid separation

Preci pitation

Adsorption

Ion ex change

Evapor ation

Dega sification

Membrane separation

Suspend ed solids

n/a

10 mg/l

100 degr.C.) b) Very high temperatures for drying oil, especially if in direct contact with hot air. (hence the preferred use of a vacuum dryer, which operates at lower temperatures ) c) Incorrect pumping, handling, where air is mixed with oil, or when it falls into tanks with such a force that considerable turbulence is caused.

224

Palm Oil Process The Principle & Operational Techniques d) Storage at too high temperatures for too long periods. e) During shipments, by over heating, incorrect placed heating coils etc. 37.2.01 In its natural state, palm oil contains anti oxidants (the most common being to copherols) and the avoidance of the exposure of too hot oil to the atmosphere will assist to keep oxidation levels low. The oxidation levels can be measured by determining the Peroxide Value (P.V.) of the hydro peroxides formed during the initial stages of oxidation. Continued oxidation will form saturated and unsaturated aldehydes and ketones. 37.2.02 A series of tests over a period of time will show the increase in P.V. (in m.e./kg), but this test is not concensive and the later formed oxidation compounds are measured using benzidine, giving the Benzidine Value (B.V.) For practical quality estimation, the sum of the oxidation products us used, commonly known as the total oxidation value ( TOTOX ) and is calculated as follows: Totox = 2 x P.V. + B.V. Good quality oil should be at maximum P.V. = ± 3 m.e./kg and have a B.V. of ± 6 at the time of shipment. 37.3

Bleach-ability can be measured by treating an oil sample by a standardized method and measuring the residual colour by comparison with a (Lovibond) tinto meter. The residual colour is due to a combination of carotene and oxidized fatty acids at high temperature and gives some indication of the amount of processing, refining etc. that will be necessary to produce good quality, palatable food products.

225

Palm Oil Process The Principle & Operational Techniques 37.4

QUALITY ANALYSIS OF PALM KERNEL.

37.4.01 Determination of Shell % in kernel i)

From a sample of 1000 to 1500 grammes of kernel the shell particles are removed , by hand.

ii) If there are any half cracked or uncracked nuts present, then the kernels in these nuts must be taken out of the shells first. iii) The percentage of separated shell particles is determined by the weight of the initial sample of the kernels. Calculation: weight of shells only ———————————— x 100 % total sample weight

37.4.02 Determination of Dirt % in kernels As for the above , but dirt is understood to be any particles which cannot be regarded as either kernel or shell , i.e. abortive fruit, fibrous matter, bunch particles etc. Calculation: weight of dirt —————————— x 100 % total sample weight

37.4.03 Percentage of broken kernels i) From the sample that has been used to find the shells and dirt percentages, the broken kernels are sorted out as well. ii) The percentage of broken kernel is calculated by weight of the initial sample: Calculation: weight of broken kernel —————————————— x 100 % total sample weight

226

Palm Oil Process The Principle & Operational Techniques 37.4.04 Determination of kernel discolouration i) Take one hundred kernels at random from the sample that has been taken for the determination of shell. dirt and broken kernel. ii) The kernels are each cut into two equal parts, perpendicularly to their longitudinal axis. iii) Of every bisected kernel one half is laid in a cut out of a special board provided with 10 x 10 holes. iv) Now the sections are checked for colour. A distinction is made between marked discolouration and no visible discolouration. NOTE:

discolouration,

slight

The distinction made is merely a subjective one and unless the check is always performed by the same person, there can be considerable differences and the check will be of little value. 37.4.05 Moisture percentage in kernels i)

Approximately 150 grammes of kernel , cleared of shells, dirt etc. are ground or minced in a small grinding machine.

ii) This should be done as rapidly as possible, to prevent desiccation. iii) 100 grammes of the ground substance are dried to a constant weight in a drying oven, using exact similar techniques and methods as used for oil. Calculation: weight of moisture ———————————— x 100 % weight of wet sample

37.4.06 Determination of F.F.A. in kernel This can be determined by extracting some oil from the kernels of the sample taken and by using similar methods os described for C.P.O.

227

Palm Oil Process The Principle & Operational Techniques 37.4.07 Oil percentage in kernels Although not necessarily a quality parameter, the laboratory can determine the oil content. From the ground sample used for moisture determination the oil content can be established using similar techniques as for the determination of oil losses. 37.5

DETERMINATION OF OIL LOSSES.

37.5.01 During the process of extracting oil and kernel from the fruit, oil losses will occur in a number of areas. Samples are taken and tests are conducted to determine where oil is lost and how much of it is lost. In order of the process, the following losses can be calculated: a) oil loss on sterilizer condensate b) oil loss on empty bunches c) oil loss on fibre ( ex pressing equipment) d) oil losses sustained by clarification e) oil losses on nuts a) Oil loss on sterilizer condensate A continuous sample should be drawn from the condensate discharge lines of the sterilizers. This can be achieved with the aid of a sampling tube, fitted with a "dropper". From the average oil content of the condensate, the measured or calculated quantity of the condensate and the quantity of F.F.B processed it is possible to calculate the oil loss to F.F.B. b ) Oil loss on empty bunches (see also section on empty bunch checking and U.S.B. under the 228

Palm Oil Process The Principle & Operational Techniques heading

Process Control)

i) From a representative sample of empty bunches, obtain two samples of 100 grammes each ( by the "mixing - quartering - mixing quartering" technique) ii) Determine the moisture and oil content of the samples by the usual method iii) The daily average or periodical average is calculated from the analytical figures (i.e. the arithmetical mean of the replicate determinations) in proportion to the total quantity of bunches processed. iv) This will produce a "weighed" average. v) Finally the ratio oil loss in empty bunches to F.F.B. is calculated via the weight of the empty bunches. c ) Oil loss on fibre. Fibre samples can be taken at various points in the process, i.e. at the presses to determine the individual press performance or at the end of the cake breaker conveyor to determine the overall oil loss on fibre etc. Sampling procedures and test procedures are similar. Sampling: i) Sampling must be done at hourly intervals during the mill operation, with the first sample to be taken one hour after the mill (pressing station) has started. ii) A good "hand full" of the sample is to be collected, including the fibre and the fines. iii) Store the sample immediately in an air tight container or bag, clearly labelled to indicate the source of the sample. iv) Store the container in the coolest convenient place near the sampling point.

229

Palm Oil Process The Principle & Operational Techniques Sub sampling: The most suitable method for sub sampling is as follows: i)

Pour main sample onto a clean sheet of paper or plastic

ii) Sort out the kernels, shells and stalks etc. from the main sample iii) Mix the remainder thoroughly, breaking up lumps etc. but ensure that no spillage of fines or fibre takes place iv) Quarter the main sample until a sample of about 500 grammes is left over, again ensuring that all the fines are included. v) Cut or chop the sample to uniform size with a suitable chopper or grinder. vi) Mix this chopped up sample thoroughly and quarter to a final size of about 15 grammes for analysis. Make sure that during the quartering fines divided for one quarter do not get mixed with other quarters. vii) The analysis of the fibre sub sample must include all the fines within that sample and be carried out immediately after obtaining the final sub sample. Analysis: Moisture: The method for moisture determination and recording is exactly similar to the one as described for the moisture determination in oil ( see 1.02 ) Oil determination (using Soxhlet extraction method) i)

Transfer the properly dried sample (from above) and keep in desiccator.

ii) Extract the oil and continue to extract until a clear solution is obtained, i.e. until no trace of oil left in the sample is observed. iii) The recording of weights should be recorded directly below the recordings of the ( previously ) dried sample. 230

Palm Oil Process The Principle & Operational Techniques iv) The weight of the extracted oil and the weight of dried fibre without oil must be recorded. v) The method of dying is as for the moisture determination, but in this case with hourly intervals. Example: Cake breaker conveyor: MOISTURE DETERMINATION Date of sample Date of analysis Thimble no

: dd/mm/yy : dd/mm/yy : ........

A) Weight of thimble : ....... Weight of thimble + sample before drying : .......

Time in oven

Time out oven

8.00 am

1.00 pm

2.00 pm

4.00 pm

5.30 pm

7.30 pm

Weight of thimble + sample after drying

B) Weight of dried sample + thimble : ........... OIL DETERMINATION: (sample after extraction)

231

C) 22.00 - 24.00 24.00 - 01.00

..........(thimble plus ..........(extracted fibre)

D) 22.00 - 23.00 24.00 - 01.00

...........( extracted ...........( oil )

Palm Oil Process The Principle & Operational Techniques Calculation: Let A = weight of dry thimble Let B = Weight of thimble + dry fibre (fibre + oil) Let C = Weight of thimble + extracted fibre (without oil) Let D = Weight of oil extracted OIL LOSS ON DRY BASIS may be calculated by at least two methods: i)

D O.L.D.B. = ————— X 100 % B-A

ii)

D O.L.D.B. = ————— X 100 % C+D-A

To decide which equation should be used, check the following: If the analysis has been carried out perfectly correct then the equation C + D = B will hold. However, some error will usually occur, so that C+D is > B, or C+D is < B. If C + D < B use equation ii) If C + D > B use equation i) If C + D = B use either i) or ii), the simplest being i) The daily average or periodic average is calculated from the analytical figures (arithmetical mean of the duplicate determinations) in proportion to the quantity of bunches handled during the period. From the figures, the quantity of fibre and the bunches handled, the ratio of oil loss in fibre to bunch weight can be calculated. d) oil loss on sludge: Sludge samples can be taken from the outlet of the individual machines, for checking their performance, or from the outlet for the "final" sludge before the disposal to the effluent treatment, for the overall loss of oil on sludge. The sampling procedures and the analysis method for both samples is identical. 232

Palm Oil Process The Principle & Operational Techniques Sampling: i)

Sampling should start one hour after the clarification station has "started" and thereafter at hourly intervals.

ii) Collect ± 500 ml from the sampling point into a suitable container and seal airtight. iii) Shake vigorously, then pour 100 ml of the well mixed sample into a measuring cylinder. iv) Pour the measured 100 ml into a 1000 ml bottle and seal air tight. v) Sampling throughout the normal operating day of the mill should produce at maximum 800 ml per shift which can all be kept in the 1000 ml bottle. vi) At the end of the day, maximum 3 bottles @ 1000 ml, clearly labelled with the source and date can be taken to the laboratory. Sub sampling and Analysis: Each 1000 ml bottle should be graduated on a 100 ml scale. The total quantity of the sample depends on the total time of operation of the mill. Assuming a 3 shift operation: There will be 3 bottles of samples i)

Shake each bottle vigorously and pour away ± half of the sample.

ii) Repeat above procedure once more iii) Mix all three bottles into one iv) From the total mixed sample, shaken thoroughly pour away half the sample v) From the remainder, shaken thoroughly, pour out a final sample of about 60 grammes for analysis into a weighed, dry beaker.

233

Palm Oil Process The Principle & Operational Techniques Assuming a 2 shift operation: There will be 2 bottles of samples i)

Shake each bottle vigorously and pour away exactly half of the samples by means of a measuring cylinder.

ii) Mix the 2 bottles into one iii) From the total mixed sample proceed as described for the 3 shift operation. Assuming a 1 shift operation: (or individual machine samples) i)

Shake the sample vigorously and pour away half the sample

ii) Shake the other half and pour out a final sample of about 60 grammes for analysis. ANALYSIS: A) Moisture determination: The method of moisture determination is the same as the method used for fibre analysis, i.e. dry until constant weight is obtained, but in this case however the drying is more critical. B) Oil determination: The final dried sample must be stored properly in a desiccator before oil extraction. The oil is to be extracted as soon as possible to prevent absorption of moisture from the atmosphere. i)

Final dried sample is quickly soaked in solvent

ii) With the aid of a spatula, the sample in solvent is scraped in to a porcelain mortar. The sample is properly and carefully ground and sheared, taking care that no solvent or solids are spilled. iii) The ground sample is then filtered, using the finest grade filter paper. Suction filtration is necessary to reduce the filtration time. 234

Palm Oil Process The Principle & Operational Techniques iv) The dry weight of the filter paper is to be recorded. The filter paper together with the solids should be placed in the thimble for immediate extraction in the Soxhlet apparatus. v) When extraction is complete, the thimble is to be dried in the oven under similar procedures as described for the fibre analysis. vi) The extracted oil is to be dried and weighed. CALCULATION OF LOSSES: Let a = weight of beaker Let b = weight of beaker + wet sample (moisture-oil-solids) Let c = weight of beaker + dry sludge ( oil + solids) Let d = weight of thimble + filter paper Let e = weight of thimble + filter paper + dry sludge (oil+solids) Let f = weight of thimble + non-oily sludge Let g = weight of extracted oil Calculation and recording of oil losses on both wet and dry basis can thus be made: c-a moisture % = ————— x 100 % b-a

O.L.D.B. = (method 1 )

g ————— x 100 % e-d

(method 2 )

e-f ————— x 100 % e-d

O.L.W.B. =

235

(method 1 )

g ————— x 100 % b-a

(method 2 )

c-f ————— x 100 % b-a

Palm Oil Process The Principle & Operational Techniques The methods 2 are usually preferred by the mill laboratories and reported in the mill control records. (With both methods recorded, there is sufficient data for statistical comparison and determination of error) e) Oil loss on nuts: Sampling procedures: Nut samples can be taken from the outlet of the depericarper, at hourly intervals The sample size should be about 750 grammes and stored in an airtight container until transferred to the laboratory. Sub sampling The final sample is obtained by mixing / quartering technique, until a sample of about 125 grammes remains Analysis: The nuts are cracked by hand and the kernels separated from the shells. From an accurately weighed quantity of 100 grammes of shells the oil and moisture contents are determined, using similar procedures as those used for other oil and moisture determinations described previously. Calculation: The percentage of oil lost in / on nuts by weight of fruit bunches is: axbxd

——————— %, in which

c x 100 a = percentage of shell to bunches b = percentage of non-oily solids in shells produced c = percentage of non-oily solids in shell used for analysis d = percentage of oil to shell analyzed.

236

Palm Oil Process The Principle & Operational Techniques It is necessary to determine the moisture contents of the shells first in order to be able to calculate the oil loss on nuts. With the method described any kernel oil adhering to the inside of the shells is included in the percentage palm oil lost on nuts. This is a small and more or less constant error and can be accepted. (It is not improbable that at least part of the oil at the inside of the shells is in fact palm oil which during the sterilization process has percolated into the nuts through the germination holes) The weighed average of the analytical figures can be calculated for a period and from this the oil loss on nuts can be established. 37.6

Other tests: A number of other tests can be performed in the laboratory, usually at the request of the mill management or engineers to determine the efficiency of the individual machines or equipment. The frequency and the type of samples/tests are often depending of the available laboratory skills and equipment. Samples taken for such tests are usually "spot - check" samples, often "before" and "after" a particular machine or piece of equipment. The analysis methods for oil, sludge, fibre, nuts, kernel etc. are as described under the various commodities, whilst special techniques for other tests are usually described and expanded upon in the manufacturers manuals etc. More recent innovations have seen the introduction of the Micro wave oven (magnetron oven) and specialised equipments to determine oil losses (e.g. "Fosslet" equipment) These improvements have all resulted in data being available in a much shorter time after the samples have been taken. The improved methods, if used and utilised correctly, allow for more frequent sampling/analysis and thus can be an important "tool" for mill management and engineers to monitor and control the process more efficiently and reduce the overall losses in the factory.

237

Palm Oil Process The Principle & Operational Techniques This type of frequent sampling / analysis can often also provide an early indication of the physical state of certain machines and the degree of deterioration in their performance, thus allowing planned and scheduled repairs and maintenance to be adjusted accordingly and maintaining optimum usage of the machinery.

238

Palm Oil Process The Principle & Operational Techniques

General Data Processed Material Sterilizer condensate: V.M.

= 95%

N.O.S.

= 4%

Oil/N.O.S.

= 9.5%

Empty bunches: V.M.

= 67%

N.O.S.

= 31%

Oil/N.O.S.

= 6%

Bunch ash: 04. - 0.5 to F.F.B and contains aprroximately: 30 - 40 %

K2O

2- 5%

P2O5

+/- 7.5 %

CaO

Press cake: V.M.

= 41 %

N.O.S.

= 55 %

Oil/N.O.S.

= 8%

Oil/N.O.S

= 0.8 %

Oil loss

= 0.5 %

Wet nuts:

239

Fibre:

with V.M. of +/- 30 % has C.V. of +/- 2500 kcal/kg

Shell:

with V.M. of +/- 15 % has C.V. of +/- 3800 kcal/kg

Palm Oil Process The Principle & Operational Techniques C.P.O. ex continuous clarifier tank

: V.M. = 0.40 - 0.50 %

after purifier centrifuge

: V.M. = 0.15 - 0.20 %

after vacuum drier

: V.M. = < 0.10 %

in storage

: V.M. = < 0.10 % : Dirt

Clarifier tank Under flow

After sludge centrifuge

: V.M.

= 85 %

: Oil

= 10 %

: N.O.S.

= 5%

: V.M.

= 95 %

: Oil

= 5%

: Oil/N.O.S.

= 12.5 %

Raw effluent: N.O.S.

=

5%

Oil/N.O.S.

= 12 %

pH

=

B.O.D.

= 20.000 - 30.000 ppm

4

After treatment:

240

pH

= 8

B.O.D.

= < 200 ppm

C.O.D.

= < 1000 ppm

= < 0.010 %

Palm Oil Process The Principle & Operational Techniques CRUDE PALM OIL Fatty Acid composition: (see also table 1, page 6-2) Acid name

C number

Type

%

LAURIC

12

Saturated

Trace only

MYRISTIC

14

Saturated

1-2

PALMITIC

16

Saturated

40 - 43

STEARIC

18

Saturated

4 - 6.5

OLEIC

18(1)

Un-saturated

38 - 40

LINOLEIC

18(2)

Un-saturated

10 - 12

LINOLENIC

18(3)

Un-saturated

Trace only

The acid molecules combine together (in 3's) with a glycerine molecule to form a fat molecule called: triglyceride. The triglyceride composition can vary considerably, pending type and composition of numerous bonds of the saturated and un-saturated acids. Other constituents of C.P.O. are carotenes and tocopherols. Carotenes give C.P.O. its characteristic orange colour, which is then removed by bleaching the oil. Carotenes are precursors of Vitamin A, which is primarily formed when the molecule splits due to the addition of water. Tocopherols are naturally occuring anti-oxidants and in C.P.O. may be as high as 800 ppm, pending the quality of the material and the process.

241

Palm Oil Process The Principle & Operational Techniques PALM KERNEL OIL Fatty Acid composition Acid

C number

Type

%

CAPRYLIC

8

Saturated

3

CAPRIC

10

Saturated

6

LAURIC

12

Saturated

50

MYRISTIC

14

Saturated

16

PALMITIC

16

Saturated

6

STEARIC

18

Saturated

1

OLEIC

18(1)

Un-saturated

16

LINOLEIC

18(2)

Un-saturated

1

P.K.O. % of dried P.K. is approximately 50 %, the residue cake composition is as under: Carbo-hydrates Proteine Fibre Water Oil Ash

242

48% 19 % 13 % 11 % 5% 4%

Palm Oil Process The Principle & Operational Techniques

Chapter #38 ADMINISTRATION AND ACCOUNTING This area can usually be split up into three distinct responsibilities, i.e: the administration of : Quality control, Maintenance, stores and spare parts holding and the Financial control. 38-1.

Quality control

38.1.01 This consists mainly of monitoring the quality of the palm products manufactured, stored and distributed, but also the quality of the raw input material (F.F.B.), the boiler feed water and water quality, the operation of the waste product sections (effluent control) etc. 38.1.02 Many of the records required and kept are to a large degree "repetitive" type records, requiring summary calculations etc. to be integrated with other administrative records. Here also the introduction of "computerized" records can provide a greater and more accurate measure of control, all resulting in (where possible) a reduction in the final cost of producing the palm products. 38-2.

Repair and Maintenance control

38.2.01 As described in chapter 35, Repair and Maintenance, the keeping of records of the machinery and equipment performance and the condition can be a positive aid to the scheduling end execution of an effective repair and maintenance program for the mill's machinery. Here also the introduction of computerized records allow a large degree of record integration and a better (cost) control of this important part of the overall operation of an oil mill. 38.2.02 Spare parts and spare part stock holding can be kept at proven and accepted minimum levels if good records are kept, all helping to keep the overall financial requirements of the oil mill down to the minimum level required to sustain effective and profitable operation.

243

Palm Oil Process The Principle & Operational Techniques 38-3.

Financial control

38.3.01. As for any other industrial operation, financial records of the cost of the operation are to be kept and calculated. These records may take the form of weekly, monthly or other time based accounts and may vary with the individual factories, companies or corporations requirements. 38.3.02 The introduction of computer based accounting can provide an option to integrate some of the direct operational costs with for instance weigh bridge records, repair and maintenance costs, transport and distribution costs etc, during the time based period which is to be covered, thus virtually providing a day to day financial control of the production cost per tonne of palm product. 38-4

General The three sections above are just general descriptions, since each individual factory will have its own, specific, requirements or system of administrative control. It is however advisable that when there is more then one plant operating within a group of plants owned by one company or corporation, that an as much as possible "standardized" format for the generated accounts and reports is created and adopted in order to allow for a reasonable degree of accuracy when comparing different factories and to allow the staff who produce and process these records and reports to become familiar and competent with the recording and calculating procedures. Mill management should make full use of all the reports and records produced and (as noted in chapter 36, Process control) should use this data as a "news paper" rather than a "history sheet" in order to maintain full control and be able to alter / modify the production process as required, when required and not at some undetermined future date, usually after costs have already risen out of proportion, or losses have already increased to intolerable levels.

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GLOSSARY of terms Absorbance ratio (carotene: chlorophyll) The ratio in which various bio-chemical palm products form during the period of growth till maturity of the palm fruit. Aerobic ponds Excavations made in earth to provide a holding space for liquid effluent in the aerobic stage. Ponds are not usually lined but have inclined earth walls. Anthesis The time of flowering. Back pressure system Method whereby low pressure (exhaust) steam from high pressure equipment (turbines) is collected and utilized for low pressure applications before released to the atmosphere. Bio-gas Usually methane based gas, in palm oil processing plants collected from effluent digesters or ponds. Bleachability The ability to reduce the (usually reddish-orange) colour of crude palm oil by chemical treatment. Blow down The release of water, solids and chemical material from boilers under pressure. Bogey The chassis, fitted with wheels, on which the sterilizer cage is transported over rail tracks. Boiler sludge An emulsion formed inside the water compartments of the boiler, usually containing water, treatment chemicals and some scale fragments. Brine bath Method to separate shell and kernels by floating the mixture in water which has its specific gravity increased by means of the addition of salt. I

Palm Oil Process The Principle & Operational Techniques Cake breaker conveyor The paddle conveyor transporting the solid material expelled from the press to the nut - fibre separator (depericarper). Capstan A motor driven vertical or horizontal shaft drum, used for marshalling cages from loading ramp to sterilizers, crane pick-up point etc. Carbo-hydrates Compound of general formula : Cx(H2O)y usually containing sugars, starch, cellulose. Carotene An orange - red pigment in palm oil. Carry over (boiler) The possibility of water and or foam being carried over with the steam leaving the boiler. Catalyst A substance which accelerates or retards the rate of chemical reactions. Chlorophyll Green pigment found in all algae and higher plant and chiefly responsible for light capture in photosynthesis. It is the site of the first stage of the transformation of light energy to chemical energy. Clarification The process of separating "pure" palm oil from the crude oil and emulsion extracted from the press liquid. Clay bath Method to separate shell and kernels by floating the mixture in water which has its specific gravity increased by means of the addition of clay (usually Kaolin). Condensate Liquid formed from steam condensing on colder surfaces. In palm oil processing sterilizer condensate is thus formed when steam condenses on the fruit and in the sterilizer vessel. Condensing capacity The ability to reduce a given quantity of steam under given circumstances to condensate moisture. II

Palm Oil Process The Principle & Operational Techniques Cone pressure The pressure exerted on the fruit mass expelled by a screw press. Consumables Materials held in stock that are not classified as either spare parts or raw materials. Crucible A small cup shaped pressed paper container commonly used in laboratories. Cutting and shearing The action of separating the fibrous material and the nuts before pressing, performed in the digester by a rotating set of "knife-arms". Decanter A specially designed high speed rotating centrifuge, usually with horizontal shaft, to separate various phases of liquid emulsions to a pre set degree into liquids and solids Dehydration (in sterilization) The reduction in moisture content due to the temperature and pressure changes during sterilization of the fresh fruit. Depericarper A set of equipment designed to facilitate the pneumatic separation of the (loose) fibre and nuts expelled by the cake breaker conveyor. Diffusion The action of steam penetration into air, thereby displacing the air. Digester drainage Under certain circumstances the drainage of "free" oil and liquid from the digester bottom, before the M.P.D. enters the press. Digester A circular vertical vessel equipped with rotating arms causing the fruit mass to be sheared and cut, thereby separating fibre from the nuts and preparing the mash (M.P.D.) for the action of pressing. Effluent Material left over after processing and extraction the palm oil and palm kernel.

III

Palm Oil Process The Principle & Operational Techniques Endocarp The shell material if palm fruit. Exocarp The outer skin of palm fruit. Extraction rate A percentage calculated to show the relation of oil or kernel recovered from the F.F.B. Feedwater Water suitably treated, heated and de-aerated to be pumped to the boiler. Fines (in laboratory tests) Fibre and shell debris in fine, dust like form. Flue gasses Exhaust gasses from the operation of the boiler furnace escaping to atmosphere through the chimney stack. Fosslet equipment Laboratory equipment calibrated to measure particular oil losses in dry and wet waste material from the process. Hard bunch percentage A percentage calculated to show the ratio or quantity of unripe fruit delivered with the overall F.F.B. to the process plant. Hardness (water) A measure of chemical quality of the water used for the boiler, usually expressed in mainly calcium and magnesium. Hydro-cyclone Equipment designed to separate shell and kernel by means of a vortex created by water flow through a cylinder. Hydrolysis (of lipids) Decomposition of lipids through the addition of water. Incinerator A furnace designed for slow and low temperature burning of the empty bunches.

IV

Palm Oil Process The Principle & Operational Techniques Inflorescence The reproductive shoot of plants, composed of, or bearing, flowers. Ion exchanger Part of the demineralization plant, where silica can be removed by an exchange process with base anion resins, usually regenerated with caustic material. Lipase Enzyme which splits lipids into glycerol and free fatty acids. Lipids Basically fat, a compound of glycerol and fatty acids. Loading ramp Equipment designed to facilitate the transfer of F.F.B from external road transport units to the sterilizer cages. Loose fruit Fruit which has abcissed from the fruit bunch on ripening. Marshalling yard The area designated to move, shunt and store the sterilizer cages, full or empty. Mash Passing to Digester (MPD) The fruit mash prepared by the digester, passed on to the pressing / extraction equipment. Mesocarp The main oil bearing tissue of the palm fruit. Mesophyll Internal tissue of leaves, other than the vascular elements, in which chlorophyll is found. Methogenic Having the capability of generating methane based gases. Mill capacity A theoretical calculation showing the quantity of F.F.B. that can be processed in a given period and at a given rate.

V

Palm Oil Process The Principle & Operational Techniques Mulch loose organic material lain on the surface of the soil, assisting in retaining soil moisture, improvement of soil structure and increasing the organic matter content. Nut conditioning Treatment given to palm nuts, prior to the process of extracting the palm kernel. Nut-fibre separator See depericarper Orifice plate Plate fitted with a hole smaller than the internal pipe diameter in a steam pipe line to reduce the flow of steam through the pipe as a result of the "throttling" action. Palm oil meal The dry cake material remaining after extracting the drying off the oily phase and moisture from decanter solids. Palm produce The combined quantity of palm oil and palm kernel extracted from F.F.B. Parthenocarpic Formation of fruit without fertilization. Pathogenic Being able to cause disease in a host. Pericarp The main oil bearing tissue in oil palm fruit, plus the outer skin. Phospholipid A combination of oil with a phosphoric acid group and a nitrogenous base. Polishing drum A rotary drum in which nuts are treated and remaining fibres are loosened from the nuts, before further process of the nuts. Pressing The action of squeezing the oil out of the digested fruit. Regenerant Material used to regenerate exhausted ion and anion exchange resins. VI

Palm Oil Process The Principle & Operational Techniques Ripple mill A rotary nutcracker, the action of which is more akin to shattering the shell than breaking the shell, without unacceptable breakage of the kernel. Rotary drum (thresher) The revolving part of the thresher machine, designed to carry the bunches up and dropping them back in the slotted drum, the action of which "threshes" the fruits from the bunch. Sand trap A tank fitted between the crude oil gutter and the vibrating screen, designed to allow sand and other (heavy) solid material to settle out. Scale ( boiler) Deposits of calcium and other solids on the water side of the heated surface of boiler tubes, drums etc. Screw press Equipment designed to extract the crude palm oil from the digested fruit by means of pressing. Senecent Grown old. Silica Silicon dioxide, hard stone like material, usually entered with water from source. Silo dryers Equipment designed to dry nut or kernel material by passing heated air through the material to be dried during a calculated retention time in the silo. Sludge Mixture of primarily oil and water Soil bearing test Test performed to establish the capacity of the soil to support structures etc. of a given weight on a given area of foundation. Soxhlet extraction A laboratory technique used to determine quantities of oil or grease mixed with normally dry material. VII

Palm Oil Process The Principle & Operational Techniques Spectral scanning A method designed to allow the detection and calculation of various components of a compound material by scanning the images of various bands of colours produced by light rays. Stack plume The characteristic elongated cloud of smoke above a chimney stack. Steam sweeping The action of forcing the air inside sterilizers down wards towards the deaeration outlets. Sterilization The action of preparing the F.F.B. for further handling and process to allow the efficient and economic extraction of palm produce. Sterilizer cages Metal baskets in which the fruit is held during the sterilization process. Sterilizer vessel A long, cylindrical vessel in which the fruit to be sterilized is placed and submitted to the influence of live steam . Stripping process Commonly used term for threshing of fruit. Tannins Group of astringent substances, particularly found in the bark of trees, unripe fruits, leaves and galls. Tenera Also called D x P as it is a cross between Dura and Pisifera. Threshing The action of removing the fruits from the bunches in a revolving thresher drum. Tippler Device designed to rotate a sterilizer cage at ground level , tipping out the fruit and eliminating the use of an overhead hoisting crane. Torque Twisting force. causing rotation. VIII

Palm Oil Process The Principle & Operational Techniques Triple peak sterilization Process of sterilization whereby cycle is divided into three peaks, separated by intermittent blow - offs, assisting in the proper penetration of steam, dehydration and pre-treatment of nuts. Vibration measurement Measurement to indicate the overall vibration, or the increase in vibration of a particular machine, thereby providing data on which a forecast of the machine wear can be based. Vibro energy separator Equipment designed to separate the solid and liquid fraction of the crude oil extracted from the fruit by the press. The equipment has a simultaneous horizontal, vertical and gyrating movement. Viscosity Fluid rating of liquids Volatile matter Term commonly used to describe moisture in oil or kernel. Weigh-bridge Equipment designed to weigh the incoming F.F.B. into the factory and the outgoing produce from the factory. Wet separation The actions performed by either hydro-cyclones or clay-bath separators. Winnowing The actions performed by pneumatic separation of material of different density, volume and weight. Zeolite Chemical substance used in the treatment of boiler water.

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Palm Oil Process The Principle & Operational Techniques

INDEX absorption : 25-23 acid sulphate soil : 31-1 administration : 38-1; 38-2 aerated lagoon : 32-5 aerobic : 32-4 aerobic pond : 32-6 aerobic stabilization pond : 32-6 aerobic suspended growth : 32-5 aerobic sludge cake : 31-7 aerobic digestion : 32-5 air flow rate : 30-5 air pollution 33-1 air release : 25-1; 25-3 air velocity : 30-4 alkali attack : 34-2 alkalinity : 34-3; 34-7 alumina : 34-1 anaerobic : 32-4 anaerobic ponds : 32-11 anaerobic sludge cake : 31-7 anaerobic tank digestion : 32-13 analysis c.p.o. : 37-1; 37-2; 37-3; 37-4; 37-5; 37-7; 37-8; 37-9 analysis p.k : 37-10; 37-11; 37-12 anoxic denitrification : 32-4 application digested effluent : 32-18 attached growth : 32-5 automated valve control : 25-19 bag filter : 33-2 batch type process : 25-19 bio gas : 32-14 bio-chemistry : 3-1 biochemical oxidation : 32-2 biological oxygen demand (b.o.d.) : 32-1; 32-2 biosynthesis : 3-2 black bunches : 36-3 bleach-ability : 29-12 blow down : 34-10 blow-off : 25-4; 25-5; 25-7; 25-8 boiler smoke : 33-1 X

Palm Oil Process The Principle & Operational Techniques boiler water : 34-1 boiler ash : 31-4 boiler boil out : 34-15 breakdown : 35-1 buch ash : 11-1 bulk density (fibre) : 30-4 bunch stripping : 25-2; 25-21 bunch trash : 28-1 bunch ash : 31-1; 31-2 by-pass : 25-5 cake breaker conveyor : 30-1 calcium carbonate : 34-1 calcium phosphate : 34-1 calorific value : 31-3 capstan : 25-20 carbohydrate : 3-1; 4-3 carboneceous b.o.d. : 32-4 carotene : 3-1; 4-2; 4-4; 29-12 carry over : 34-2; 34-3 centrifugal separator : 29-9 check list : 35-7; 35-8; 35-9; 35-10; 35-11; 35-12; 35-13 chelant programme : 34-9 chemical oxygen demand (c.o.d.) : 32-1; 32-2 chloro-plast : 4-4 chlorophyll : 3-1 clarification : 25-1; 29-2; 29-3; 29-7; 29-8 clay bath : 30-11 co-ordinated phosphate programme : 34-10 coagulation : 34-3; 34-9 combustion : 31-1; 33-1 composition : 28-2; 29-7 computer : 35-2 condensation/condensate : 25-3; 25-5; 25-6; 25-10; 25-11 condition monitoring maintenance : 35-5 cone pressure : 27-4 cone control : 28-4 constant bleed : 25-6 constant pressure : 25-7 consumables : 35-1 contamination : 28-4 control methods: 32-8 convection current : 29-7 conveyor : 25-25 XI

Palm Oil Process The Principle & Operational Techniques copper : 29-12 cracked mixture : 30-10 cracking ring : 30-9 crude oil gutter : 29-1 crude palm oil (c.p.o.) : 1-1; 26-1; 28-2; 29-1; 29-3; 29-7; 29-8 crude oil tank : 29-2 d x p : 30-1 de-aeration : 25-3; 34-12 de-gasified water : 34-5 de-watered sludge : 31-6 decanter : 29-8; 31-6 dehydration : 25-2; 25-8 demineralization : 34-6 depericarper : 30-1 deterioration : 29-9 determination oil losses : 37-12; 37-13; 37-14; 37-16; 37-18; 37-20 diffusion : 25-3; 25-4 digester : 27-1; 27-3 dilution : 27-4 dirt : 29-9; 29-10 disposal : 29-9 dry separation : 30-11 drying : 29-9 ducting : 30-5 dura : 1-2; 1-3; 28-1; 30-1 dust collector : 33-2 dust cyclone : 33-2 dynamic (oil) recovery : 29-4; 29-6 efficiency : 28-2 effluent : 32-1 elaedobius kamerunicus : 9-2 electricity : 34-1 electricity : 34-25 elevator : 25-25 empty bunches : 25-24; 31-1; 31-3; 36-4 emulsion layer : 29-7 emulsion : 27-3; 27-4; 29-3 endocarp : 1-2 enzyme : 3-2; 25-1; 30-13 evaluation : 29-10; 30-15 examination of f.f.b. : 36-2 extended aeration ponds : 32-13 external treatment : 34-3 XII

Palm Oil Process The Principle & Operational Techniques extraction rate : 24-1; 26-3; 28-1 f.f.a. premium : 29-11 facultative process : 32-4 facultative pond : 32-7 fan characteristics : 30-6; 30-7 feed water : 34-10; 34-11 feed screw : 27-1 fibre fuel : 30-12 fibre : 30-4; 31-3; 31-4 fibre / nut separator : 27-2 fibre:nuts : 28-1 field disposal : 31-2 filtration : 34-3 flash off : 25-6 flocculation : 34-3 flowers : 1-2 foaming : 34-2 free fatty acid : 3-2; 24-3; 25-1; 25-6; 29-10 free oil : 27-3; 27-4 fresh fruit bunches : 1-1 fruit cage : 25-4 fruit transport : 24-1; 25-20 fuel : 31-3 fuel/steam/power balance : 34-18 furrows : 32-18 gases : 34-3; 34-8 glycerol : 3-2 gravity : 29-7 hand press : 27-1 handling (f.f.b.) : 28-4 hardness : 34-3; 34-4 harvest interval : 28-3 harvesting efficiency : 28-4 heat transmission : 25-10 heat transfer : 34-2 heat loss : 25-20 heat penetration : 25-4 henry's law : 34-12 hoisting crane : 25-20 homogenization : 29-2 hydraulic retention time (h.r.t.) : 32-9 hydraulic press : 27-1; 30-1 hydro cyclone : 30-12 XIII

Palm Oil Process The Principle & Operational Techniques hydrolysis : 3-2; 29-10 hydroxyl group : 4-2 hygroscopic : 29-10 incinerator : 11-1; 31-1; 33-3 inflorescence : 1-2 instripped bunches : 36-4 internal treatment : 34-9 inventory control : 35-33 ion exchange : 34-3 iron oxide : 34-1 iron : 29-12 isopentenyl pyrophosphate : 4-4 kernel losses : 28-5 kernel drying : 30-13; 30-14 kernel recovery : 30-13 kernel extraction rate : 28-1 kernel cleaning : 30-14 kernel / shell separation : 30-10; 30-11 laboratory : 37-1 land application effluent : 32-17 linoleic acid : 4-1; 5-2 lipases : 4-1; 4-2 lipids : 3-1 liquid scrubber: 33-2 loading ramp : 24-2 lubrication : 25-6 m.p.d.: f.f.b : 28-1 m.p.d.analysis : 26-1 machine history : 35-3 machine records : 35-2 magnesium : 31-2 magnesium hydroxide : 34-1 magnesium silicate : 34-1 maintenance 35-1 mash passing to digester : 26-1 maturity : 5-1 melavonic acid : 4-4 mesocarp : 1-2; 25-1; 26-2; 26-3; 29-3 methogenic phase : 32-11 micro aerophil : 32-4 moisture : 29-9; 29-10; 30-2 moisture content : 4-2 monitoring equipment : 35-4 XIV

Palm Oil Process The Principle & Operational Techniques mould : 30-13 mulch : 11-1 mulching : 31-2; 31-5 multiple peak sterilization : 25-12 multiple sterilizers : 25-7 newton's law : 29-7; 29-8 nitrification : 32-4 nitrogen : 31-2 non oily solids : 29-3 nut / fibre separation : 30-3 nut / fibre : 30-1 nut cracking : 30-9; 30-10 nut treatment : 30-8; 30-9 nutrient value : 31-2 oil palm : 1-2 oil bearing cells : 25-1; 27-1 oil : 28-1; 29-3 oil losses : 25-23; 25-24 oil recovery : 29-8 oleic acid : 4-1; 5-2 organic matter : 34-3; 3408 orifice plate : 25-12; 25-18 other laboratory tests : 37-21 oxidation level : 29-2 oxidation : 29-9; 29-10; 29-12 oxygen attack : 34-2 paddles : 30-1 palm oil meal : 31-6 palm produce : 28-2; 28-5 palm oil mill effluent(p.o.m.e.) : 32-1 palm kernel : 1-1; 25-2; 28-2; 28-5 palmitic acid : 5-2 parthenocarps : 1-3; 26-2; 26-3 peak demand (steam) : 25-11; 25-12 peak yield : 1-2; 10-1; 11-1 penalty : 30-16 percolating trench : 32-18 percolation : 31-6 pericarp : 1-2 permanent magnet : 25-25 phosphate : 34-9 phospholipids : 3-1 phosphorus : 31-2 XV

Palm Oil Process The Principle & Operational Techniques physical properties of oil : 29-7 pneumatic air stream separation : 30-3 polishing drum : 30-8 pollination :1-2; 9-1 potassium : 31-1; 31-2 precipitation : 34-2 predictive maintenance : 35-1; 35-5 premium : 30-16 press cake : 27-1; 30-2 press (twin screw) : 28-1 pressing : 28-1 pressing (extraction) efficiency : 28-5 preventative maintenance : 35-1; 35-5 process control : 36-1 proteine : 3-2 proto-plast : 4-4 pure oil : 29-9 quality control : 37-1 quality : 28-3; 29-12; 30-11; 30-13; 30-14; 30-15; 30-16 recovery % : 28-5 retention time : 27-3; 30-2 return conveyor : 25-26 ringelmann : 33-3 ripeness : 1-1; 2-1; 5-1; 10-1; 24-2 ripple mill : 30-10 rotary drum : 25-21 rotating drum separator : 30-3 sampling : 25-21; 26-1 sampling : 36-5 sand trap / filter : 29-1 sand cyclone : 29-1 scale / deposits : 34-2 screen aperture : 29-2 screening : 29-1 screw speed : 28-4 screw press : 27-1 scrubber : 31-6 seasonal winds : 20-1 secondary depericarper : 30-8 seeding effluent : 32-11 sequencing : 25-19 settling : 29-1 shell : 30-12; 31-4 XVI

Palm Oil Process The Principle & Operational Techniques silica : 34-1; 34-7 site selection : 17-1 slag / clinker : 31-5 slip : 28-5 sludge : 29-9 sludge separator : 29-9 soda ash : 34-15 soil pH : 31-1 solids separation : 32-7 solids : 29-9; 31-1; 31-5; 31-6 sprinklers : 32-17 stabilization : 32-4 staff training : 35-5 standardization : 16-1 static tank recovery : 29-4; 29-5 steam turbine : 34-25 steam distributor : 25-4 steam demand : 25-9; 25-10 steam jacket : 27-1 steam : 34-1 steam pressure : 25-2; 25-7 steam requirement (calculation) : 34-17 steam consumption : 25-9; 25-11 steam sweeping : 25-3 sterilization : 25-21; 25-19; 28-4 sterilized fruit : 25-25 sterilizer : 24-3 sterilizer cycle : 25-6; 25-7 stirring arms : 27-3 stoke's law : 29-7 stones/debris : 25-25 storage : 29-9 substrate : 32-4 super natant : 32-14 supplementary fuel : 31-3 suspended solids : 32-1; 34-3 suspended growth : 32-5 tannin : 3-1 temperature : 25-4; 29-1; 29-2; 29-8; 30-13 tenera : 1-2; 1-3; 28-1 tertiary maturation pond : 32-7 theoretical oxygen demand (th.o.d.) : 32-3 thermophilic reaction : 32-9 XVII

Palm Oil Process The Principle & Operational Techniques thresher speed : 25-22; 25-23 thresher : 25-20; 25-21; 25-24 throttling : 25-11 through put : 27-1; 27-2 tippler : 25-20 tocopherol : 3-1; 4-2 torque : 28-5 total oxygen demand (t.o.d.) : 32-3 total solids : 32-1 total organic carbon (t.o.c.) : 32-3 total dissolved solids : 34-8 treatment types : 32-8 tri sodium phosphate : 34-15 tube failure : 34-2 turbulence : 25-3; 25-4 unstripped bunches : 25-21; 25-24 vacuum de-aerator : 34-6 vacuum dryer : 29-9 variables : 28-3 velocity (table) : 30-5 vertical column separator : 30-3 vibrating screen : 29-1; 29-2 vibro energy separator : 29-2 viscosity : 29-1; 29-3; 29-7; 29-8 waste disposal : 31-1 water : 29-3 weigh-bridge : 24-1 wet separation : 30-11 work orders (job cards) : 35-3

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