Chemical Technology

4/22/2009

A.C. TECH

CHEMICAL ENGINEERING

Chemical Technol Technology ogy | Prof. Dr. V. Partha

Chemical Technology Last updated: updated: Apr 1, 2009 2:46 PM

Chemical Technology Last updated: updated: Apr 1, 2009 2:46 PM

TOPI C 1: CHEMI CAL P ROC ROCES ESSING, SING, UNIT OP ERATION & UNIT P ROC ROCES ESS S

Chemical Che mical P rocess Selection, Design and Operation Adequate and flexible initial design is essential for the promotion of a chemical plant organic product or inorganic product. In older days it was classified as inorganic chemical technology and organic chemical technology. Subsequently the oxford university made it as chemical works organization and management. Some factors that must be considered in planning a plant are discussed in this section. The Process Engineer is an expert in the current aspects of chemical process design. Practical experience is a must if  the senior design engineer is able to foresee and solve the problems of production, such as maintenance, safety and obeying the government, environmental by loss and control. Experience consultants either individuals or professional consulting firms are able to advise, design and for erection of chemical plants. Chemical Che mical Pr ocess Control and Instrumentation Automatic and Instrument control contr ol chemical processes are common common and essential. Instruments should shoul d not be chosen simply to record a variables, of the process. But their function is to assure consistent quality by sensing controls, recording and maintaining desired operating conditions. Instruments are the essential tool for modern processes. processes. They are classified as 1. Indicating Instruments

2. Recording Instruments

3. Controlling Controll ing Instruments

Two types of Instruments are currently used as analogue and digital. Analogue Instruments such as pressure spring thermometers and Bourden Gauges shows results by mechanical moments of some type of device which is directly proportional to the quantity measured. On the other hand, digital devices are converts the quantity measured into a signal and electric circuits converts the signal to read the numerical values forward by control. Now the computers can monitor and regulate outputs from both the analogue and digital devices according to a prearranged program, also general conventional digital inputs are required. Chemical analytical control has been used in day to day factory procedures for analysis of incoming raw material or outgoing products. Thus quality chemicals are produced more in these days reliably their when human analysed control were used. The latest advancement are the chromatography system, many spectroscopy spectroscopy have been automated an install of on-line basis for the process to run continuously without the problems encountered manually before. Role o f Chemical Chemical Engineers Chemical Engineers are trained primarily to work in chemical industries. some of the vital role of the chemical engineers are as follows; Chemical Process Economics Engineer are totally different from Scientist by their customers of cost of production and profit generator. Therefore the objective of engineer should be to deliver safely the best product or most efficient service at lower cost to the employer and the public who consumes the product. Material Balance Yield and conversion are the chemical prospects from the basis for the material balances which is useful for cost determination. Materials and their quantities from the standard practices are tabulated in the flow charts, energy given are observed for the chemical reactions and energy is frequently a major cost in chemical plants but it often possible by altering the process procedures by using modern separation technologies like “RO” and  “Advanced Separation Processes” to produce high quality chemicals with low energy consumption. 22/04/09

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Plant Location The location of the chemical plant is decided ourselves by the availability of raw materials, transportation, market and power. Now the environmental constituents, water supply, availability of efficient labor, cost of  land and waste disposal facilities form the criteria for the plant location. Construction of Plant For small and large companies construction engineering organizations are available that will built a plant and participate in its design. Some large chemical companies have their own civil construction department and starts their own plants. The advancement of this is the worker who is going to operate the equipment can be more intimately corrected to the constructions and be familiar themselves for the future alternatives, expansion or modifications. In built-in plants the top engineers are chartered engineers qualified for the development activities. They have been trained and suitably examined to guarantee technical competency and owe personal responsibility. They are now called as functional consultants and registered firm for dealing with legal aspects with proper training. Research and Development adequate and skilled research with patent protection is necessary for future profits. In the chemical process industries one of the outstanding tactics is rapidly changing processes, new raw materials and ne w markets. Research creates these changes and the factory will have a competitive progress. This research brings about development and the adoption of ideas, concepts, concepts, methodologies form the production of th e industry. The results and benefits of research establishes the developing coutry on the road of progress and raise the level of life of common man. Chemical Che mical Engineer in co ming years 1. 2. 3. 4.

Resources particularly energy and feed back for the Fertilizers and Heavy Chemical Industries. Infrastructure for Transportation and Telecommunications. Protection of the Environment. Development of Agro Industries where utilization of waste from Agro industries and exploitation of  value added products from wastes. 5. Transformation of Rural Economy, Industrialization and Privatization where the profits are less and consumption is more. 6. Problems of less Technical context are, The latest research and development have classified the following new industries; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Cryogenics in Chemical Technology Chemicals from Sea Air as a Chemical Raw Material NUPLEXES ( Nuclear Power Agro Industrial Complexes ) Proteins from Petroleum Fermentation and Single Cell Proteins from Animal horns. Food Industries Coal Chemicals Newer Petrochemicals Pesticides Pharmaceuticals Industries Metallurgical Industries Water treatment & Air Pollution Control

The chemical chemical process process industry had its growth from pre scientific scientific chemical chemical industries followed followed by scientific scientific chemic chemical al indust industry. ry. The growt growth h with with restrains restrains,, green green challeng challenge e to chemic chemical al industry industry and the modern modern separations process involved in the indian chemical industry seen today. We define Chemical Engineering as a synthesis of chemistry and engineering. A Chemical Engineering therefore carries out on a large scale reactions developed in the laboratory by the chemist. The Major Areas of Work within Chemical Engineering are, Research Process Development 22/04/09

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Process Design Evaluation of Design Plant Design Construction Production Supervision Plant Technical Services Sales of the Product The Researc Research h is divided divided into three categ categories ories like Fundam Fundamenta entall Researc Research, h, Explorat Exploratory ory Researc Research h and Process Research.

S.No.

1

2

3

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Industry

Inorganic Chemicals

Organic Chemicals

Petr oleum&   Petrochemicals

Typical Products

End User

H2SO4

Fertilizers, Chemicals, Petroleum Refining, Paints, Pigments, Metal Processing and Explosives

HNO3

Explosives Explosives & Fer tilizers

NaOH

Rayon, Film Processing, Petroleum Refining, Pulp &  Paper Industry, Lye, Cleaners, Soap & Detergents, Metal Processing

Acetic Anhydride

Resins, Plastics & Nylon

Ethyl Alcohol

Antifreeze agents, Cellophane, Dynamite & Syn. Fibres

Formaldehyde

Plastics

Methanol

Mfr. Of Formaldehyde, IMS(Industrial Methylated Solvent) & Antifreeze agent

Gasoline

Motor Fuels

Kerosene

Fuel

Oi l

Lubrication & Heading purposes

Ammonia

Fertilizer & Chemicals

Ethanol

Acetaldehyde solvents &   other miscellaneous chemicals

Alkyl Ar yl Sulfonate

Detergents

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4

5

Pulp & Paper

Pigments & Paints

S ty r e n e

Syn. Rubber, Polymers &   Plastics

Paper

Books, Records & Newspaper

Cardboard

Boxes for packing

Fiber Board

Building mater ials

Zinc Oxide (ZnO)

Pigments for paints, inks, plastic, rubber, ceramics and linoleum

TiO 2 Carbon Blade

Drying Oil

Lead Chromate Linseed Oil

6

Rubber

Phenolic Resins

Basic kequer warmish &   enamels

Alkyl Resins

Ion exchange resins and constituents of enamel

Natural Rubber(Isoprene)

Automobile tyr es, moulds, sheets, footwear and insulation

Syn. Rubber (Neoprene) Butyl Rubber 7

Plastics

Phenol For maldehyde

Var ious users in all areas of   everyday life

Poly Styrene Polymethyl methacrylate PVC Polyethylene Polyster 8

Synthetic Fibers

Rayon

Clothing

Nylon Acrylics Polyster 9 22/04/09

M i n e r al s

Glass & Ceramics www.sdsenthil.com

Windows, containers, bricks &   pipe tubes 4 o f 50

Cement

Concrete for construction of   buildings, highways, etc.

Coal

Fuels, coke and its by-products

10

Cleansing Agents

Soaps & Detergents

House hold cleaning &   Industrial cleaning. Sodium alkyl aryl sulfonate is also used as wetting agent.

11

Bio Chemicals

Pharmaceuticals & Drugs

Health & Medicine applications

Fermentation product like penicillin

Medical use

Ethyl Alcohol

Solvent and Beverages

Food Products

Human sustance

Steel, Cu, Al & Zirconium

All the Building materials, machinery etc.

Uranium

Nuclear fuel

12

Metals

The largest tonnage inorganic chemicals is H 2SO4. It is consumed by industry in the manufacture of other products. Thereby it reaches the public knowledge vary scarely. Large quantities are consumed by petroleum and metal industries. The important organic chemical include alcohols, dyes, dye intermediates used to produce other chemicals. Ethyl alcohol was initially produced by bio chemical fermentation before the second world war. But now it is produced primarily from petroleum on the latest discovery of natural gas. The important petroleum products are gasoline, l ubricants, petrochemicals, other fuels and miscellaneous chemicals. Since the second world war petrochemicals have assumed a commander role in the economy. The largest petrochemical ammonia is produced by reaction of H 2 from natural gas or petroleum with N 2 available available in in the Air. This Ammonia reacts with CO 2 to produce produce Urea in a fertilizer plant. Normally Normally there are five different units in the fertilizer manufacture from coal based mines. 1. 2. 3. 4. 5.

Oil & Gasification plant Benfield De-sulphurization plant Ammonia plant CO2 plant Urea plant

The tendency of Urea is to form BIURETS which are used as regenerator salts in the metallurgical applications. Many plastics and synthetic detergents are produced with the help of oil refineries.

Unit Operation The basic physical operations of chemical engineering in a chemical process plant, that is distillation, fluid transportation, heat and mass transfer, evaporation, extraction, drying, crystallization, filtration, mixing, size separation, crushing and grinding, and conveying. In simple terms, the operation which involves physical changes are known as Unit Operation. 1. Distillation is a unit operation is used to purify or separate alcohol in the brewery industry. 2. The same distillation separates the hydrocarbon in a petroleum industries. 22/04/09

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3. Dry grapes and other food products or similar drying of filter precipitate like rayon industry where

yarn is produced. Absorption tion of oxygen oxygen from air in a fermenta fermentation tion process process of a sewag sewage e treatm treatment ent plant plant and half  4. Absorp hydrogen gas in a process fr liquid hydrogenation of oil. 5. Evaporation of salts solutions similar to evaporation of sugar solution in the industry. 6. Settling and sedimentation of suspend solids similar to minimizing and sewage treatment plant.

Flow of liquid hydroc hydrocarb arbon on in a petro petroleu leum m refiner refinery y and flow flow of milk in a daily daily plant plant for the 7. Flow solidification in spray dryer.

Classification Cla ssification of Unit Operations 1. Fluid Flow : Concerns the principle that determine the flow or transformation of fluids from one

2.

3.

4. 5. 6. 7. 8. 9. 10.

point to another. The fluid can be a liquid or a gas. This unit is entirely based on Bernoulli e's equation followed by continuity correlation. Heat Transfer : Deals with principles that govern accumulation and transfer of heat and energy from one place to another. The three concepts followed here are conduction, convection and radiation. Evaporation : A special case of heat transfer which deals with the evaporation of volatile solvent such as waste from a non-volatile solute such as salt or any other material in the solution. The evaporation of trichloro-ethylene a cleaning agent in the automobile service industry and acetone in the case of glassware in a chemical process industries follow this unit operations. Drying : An operation in which volatile liquids (usually water) are removed from solid material. Distillation : An operation where a components of the liquid mixture are separated by boiling because of their difference in vapor pressure. Absorption : A process whereby a component is removed from gas mixture by treatment with liquid. Liq-Liq Extraction : A process in which a solute in a liquid solution is removed by contact with another liquid solvent that is relatively ir reversible with solution. Liq-Solid Leaching: Leaching : It involves treating a finely divided solid with a liquid that dissolves and removes a solute contain in the solid. Crystallization : The removal of a solute such as a salt from solution by precipitation in the industries for large scale operations, electrostatic precipitation is operated for this concept. Mechanical physical separation : This involves involv es separation of solids, liquids or gases by mechanical means such as filtration, settling, size reduction which are classified as separate unit operations. The outline of unit operation defines the settling tanks for sedimentation, filter press for separations, pressurized spheres for ammonia storage, pellatising for fertilizer compounds, pneumatic conveyors conveyors for cement cement industry, bucket wheel elevators for thermal power stations stations and belt conveyors for core industries and many more in operation.

Stacks Gases are discharged into the ambient atmosphere by stacks (referred to as chimneys in industry) of  several types. The chemical process steps involved the foll owing; 22/04/09

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1. 2. 3. 4.

Preparing the Reactors React them Separate the Products Purify the Products

The purpose of chemical industry is to start from one and other chemical raw material arrive at a consumer product through a group of physical and chemical products. Therefore it is called as a creative industry rather than assembly industry. This mainly fall into inorganic, natural products, organic chemicals and metallurgical industry.

Unit Processes Processes that involve making chemical changes to materials, as a result of chemical reaction taking place. For instance, in the combustion of coal, the entering and leaving materials are differ from each other chemically. Coal and Air enters, and flue gases and residues leave the combustion chamber. Combustion is therefore a unit process. Unit processes are also referred to as chemical conversions. In simple terms, the process which involves chemical changes are known as Unit Processes. Together with unit operations (physical conversions), unit processes (chemical conversions) form the basic building blocks of a chemical manufacturing manufacturin g process. Most Most chemical processes consist of a combination of  various unit operations and unit processes.

1. Alkylation : Addition of alkyl radical (CH3) with side chain final product. This alkylation process is widely used in organic chemicals and petroleum industries. The reaction is given as, as, C=C-C-C + C-C-C

2. Amination by Ammonolysis: Ammonolysis : Cl-CH2CH2Cl + 4NH3 ------->NH 2CH2CH2NH2 EDC

Ethylene Ethylene Diamine

This reaction is used in manufacture of dye stuffs, organic chemicals and synthetic fibres. 3. Amination by Reduction: Reduction : CH3CHNO2CH3 + 3H2 ------ > CH3CHNH2CH3 2 Nitro Paraffin Iso Propylamine This unit process is also used in the manufacture of dye stuffs and organic chemicals. 4. Amino Oxidation: Oxidation : CH3CH2CH3 + NH3 + 1.5 O 2 -----> CH2:CHCN + H20 Propylene Acrylonitrile This reaction is used in the manufacture of plastics and synthetic fibres. 5. Calcination : CaCO3 ---Heat ---> CaO + CO2 Limestone Lime This reaction is used in the cement industry. 6. Carbonylation: Carbonylation: CH3OH + CO ----- > CH3COOH 22/04/09

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Methanol

Acetic Acid

This is used in the manufacture of organic chemicals. 7. Carboxylation: Carboxylation:

This reaction is used in the organic chemical industry. 8. Combustion: Combustion : CH4 + O2 ------ > CO2 + 2H2O

( Process Heating )

9. Condensation: Condensation : C6H5CHO + CH3CHO ------ > C6H5CH:CHCHO + H2O Benzaldehyde+Acetaldehyde

Cinnamaldehyde

10.Cra 10.Cracking cking or Pyrol ysis: ysis : C-C-C-C-C-C-C --------> C-C-C + C=C-C-C This reaction is used in petroleum destruction and distillation of coal.

1. Fluid - Solid Contact ontact:: Represented by fixed bed reaction. It is most widely used in catalytic reactor used with precious metal catalyst to minimize attrition losses. The catalyst used in the form of pellets. It can represented by the following figure.

This is used in the packed column. The design of the column is determined by the breakthrough curve, equilibrium line for the given system of adsorbent and adsorbate's. The volume of the reactant coming from the top and the volume of which the product leaves the column, residence time, distribution decides the dimensions of the column. It is contrary to the fluid bed reactor where the bed is fluidized. Once the minimum fluidized velocity is reached the porosity of the bed is faster in a fixed bed reactor but varies from the fluidized bed where the porosity changes according to the height of the bed. 2. Fluid - Solid Separation: Separation : (Centrifugation) This operation separates very finely divided solids from liquid or mixture of liquid and liquid emulsion.

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3. W et Scrubber Scrubber : It is an effective means of removing suspended particles from gas string by contact with li quid shower.

When solids are used in the place of liquid the operation is called Dry Scrubber. In the manufacture of  MEK, wet scrubber is used and in other selected process industries Dry Scrubbers are used, Scrubber just washes away the impurities and separate the product for further purification. 4. Filter Press: Press : It is the simplest type of pressure filtration. the two important parts of the filter press are plates &  frames and fabric used in between the two are made of variety of corrosion resistant materials. In the laboratory scales asbestos cloth are used for filtration at different pressures. The operation decides the value of specific cake resistance, filter medium resistance and compressibility of the chemical namely namely Kieselghur a specific specific compound compound in the nature of diatomacceous earth which are used in the application of bio-physics and cyrstallography.

5. Fluid Storage: Storage : Tanks are widely used for storage of liquids of all types and atmospheric pressure when the liquid is highly volatile there is a floating roof which acts as lid for chemicals as and when the vapour pressure at which signifying the boiling point of liquid the roof changes its position and deserves the liquid from going out to the atmosphere.

6. Pressurized Spheres: Spheres : Pressurized spheres are used for pressurized storage of liquefied gases or high vapors. The pressure permits safe storage with no vapor losses. This is seen in the fertilizer plant where ammonia is stored in spheres.

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7. GasGas-Liquid Liquid Contact Contact:: (Absorption) The best example is Absorption. It is used for taking a soluble gas in a solvent liquid and producing a solution plus an exit gas. Hydrogen Sulphide is removed from hydrocarbon by the absorption process.

8. Adsorption Adsorption:: It is classified into physiorption and chemisorption according to the process applied. The former one is almost a physical change or physical transformation while a later represents a chemical reaction which is a irreversible one. the common effluent treatment plants of varies nature lied textile effluents, sewage treatment, ETP plants in chemical industry, removal of hazardous solid wastes, etc are dealt with adsorption method and the adsorbent is regenerated over a period of time and used again and again. 9. Heat Exchangers: Exchangers : The various cooling towers of natural draft and forced draft are example of industrially applied H.Es. These are common facilities in the thermal power stations and in chemical industries the application of  shell & tube heat exchangers are widely used. this is an excellent application of heat transfer from one medium to the other. 10.Membrane 10. Membrane Separation: Separation : Dialysis is used to separate metals in solution having widely different molecular weight. for example caustic from sugar solution or cellulose. 11.Size 11. Size Reduction: Reduction : This involves crushing, grinding, pelletizing and prilling. Pelletizing is used in pharmaceutical industries and prilling used the manufacture of Urea.

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Modern chemical processes are offer extremely complex operations involving 100s of pieces of equipment. without a systematic approach it would be i mpossible mpossible to analyses an existing e xisting process or to design equipment process. The typical chemical process is analyzed with the following interdependent considerations like, -

Mass & Energy Balance Thermo chemistry Unit Operations Plant Equipment Ancillary Equipment Process Plant Diagram Instrumentation Control Economics which deals with net profit before taxation profit after taxation dividend paid to the public and share holders. Once the process as been developed and completed attention can be made to access access the various liabilities, resource and assets. Alternatives and the remaining choices can be ranked in the order of desirability. They are as follows; -

Effectiveness for reducing waste Technical Risk Extended of current views in the facility Industrial Precedent Capital and Operating cost incurred Effect of the Quality of the product Impact Impact of Plant Operations Required time for Implementation Other aspects important in the particular situation according to the industrial

Conservation of Energy: Energy : dE = Q - W dH = Q - Ws

This is a steady state batch process. process. Thia is for flow process. process.

Q--> Heat energy transfered across system boundary. W-->Work energy ener gy transfered across system boundary. Ws->Mechanical Ws->Mechanical work wor k energy transfered across system boundary. E--> Internal energy of the system. dE, dH--> Changes in Internal Energy & Enthalpy during the process.

we are already classified the various unit operations and below is a particular basic column of mass transfer equipment.

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1. Distillation : It is classified into Batch and Continuous Fractionation. a. Batch Fractionation:

Used for intermittent operation and handling of small volume of feed and products. b. Continuous Fractionation:

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These are used for high volume continous seperation of complex mistures such as petroleum fractions connected to appropriate pumps, re-boilers, condensers, scrubbers, strippers strippers and finally fin ally automatic controls. 2. Drying of Solids: Solids : Spray Dryer , Rotary Dryer & Tunnel Dryer are some example of these types. 3. Evaporation Evaporation:: Open pan evaporators and multiple effect evaporators as used in sugar and salt industries for example. Among these halogen family we have technology to separate chlorine and fluride but production of  bromine from the 'sea brine'is almost not put into practice as the bromine chemicals is highly corrosive and necessary precaution has to be laid out for practical purpose. 4. Extraction Extraction:: Liquid - Liquid Extraction Solid - Liquid Leaching are examples for this process

5. Fluid Handling Equipments: Equipments : Centrifugal pumps Reciprocating pumps Jet ejectors 6. Fluid - Solid Contacting ontacting:: Fixed Bed Fluidized Bed Moving Bed, etc. 7. Fluid - Solid Separation: Separation : Centrifugation Settling Tank / Sedimentation Wet Scrubber / Dry Scrubber Crystallization Rotary Filter Filter Press Cyclone Separator Electro-static Preciptator Bag Filter Thickeners based on Kynch Theory 8. Fluid Storage: Storage : Gas Holders Tanks Pressurized Spheres Underground Caverns which are used for the purpose of Natural Gas Storage. 9. Gas - Liquid Contact Contact:: 22/04/09

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Absorption Stripping 10.Heat 10. Heat Exchangers: Exchangers : Fired Heaters Re-boilers Condensers Shell & Tube Heat Exchangers Jacketed Kettle Quenching applied in conventional Heat Transfer and Metallurgical Operations. 11.Membrane 11. Membrane Separation: Separation : Dialysis Gaseous Diffusion 12.Mixing 12. Mixing:: Agitation Solids Blending 13.Size 13. Size Reduction & Enlargement: Enlargement : Crushing Grinding Pelletizing 14.Solids 14. Solids Handling: Handling : Pneumatic Conveying - Juices transfered to 200 km in Brazil Bucket Elevators - Coal Industries Screw Conveyors - Tooth Paste, Turbine Liquids Belt Conveyors 15.Solid 15. Solid - Solid Sepa Separation ration:: Screening Elutriation Froth Rotation Rotation Jigging Magnetic Separation

CHEMI CAL REACTORS The Reactor is the heart of the chemical process. The design of an industrial chemical reactor must satisfy the requirements in four main areas. 1. 2. 3. 4.

Chemical Factors Mass Transfer Factors Heat Transfer Factors Safety Factors

1. Chemical Factors: This involve the kinetics of the reaction weather it's first order or second order and based on this chemical reaction engineering is built on the design must provide sufficient residence time to proceed the reaction for the required degree of reaction and conversion to product. 2. Mass Transfer Factors: The reaction rate of homogeneous reaction may be controlled by the rate of diffusion of reactants rather than the chemical kinetics of Langmuir isotherm and Frendlich isotherm. 3. Heat Transfer Factors: 22/04/09

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These describes weather the reaction is exothermic or endothermic. In Exothermic, heat is released outside and In Endothermic, heat is absorbed by reactants. The value of heat of reaction is necessary to operate the chemical reactor. 4. Safety Safety Factor s: This involve the confinement of any hazardous reactant and products as well as the control of reaction and process conditions. Based on these factors the Reactor Types as follows; a. Mode of Operation - Batch or Continuous b. Phases Types - Homogeneous Homogeneous or Heterogeneous c. Reactor Geometry - Flow Pattern & Process of contacting the phases. The five major classes of Reactor; Reactor; i. Batch ii. Stirred iii.Tubular iv.Packed Bed (Fixed) v. Fludised Bed Compounds like pigments, dye stuffs, pharmaceuticals and polymers are manufactured by Batch Processes. Processes. The Latest Heat Exchangers are Direct or Contact Exchangers In addition to Double Pipe Exchanger, Shell & Tube Exchanger and Plated Frame Exchanger.

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TOPI C 2: CHLOR A LKA LI IN DUS DUSTRY TRY , INDUSTRIAL ACID, CEMENT, CEMENT, GLASS GLASS &  CERAMI CS AND PULP & PA PER

Sodium Chloride Sodium chloride is the basic raw material for many chemical compounds such as NaOH, Na 2CO3, Na 2SO4, HCl, Na2PO4, Sodium Sodium Chlora Chlorate, te, So Sodi dium um Chlorit Chlorite e and its sourc source e of many many other other produ product cts s throug through h its derivatives. Practically all the chlorine products in the world is manufactured by electrolysis of Sodium Chloride (NaCl), a common salt is manufactured in three different ways; 1. Solar evaporation of sea water 2. Mining of rock salt 3. From well brines

1. From saturated Brine by Multiple Effect Evaporator Pr ocess Brine contains water 73.5%, sodium chloride 26.3%, calcium sulphate 0.12%, calcium chloride 0.003%, magnesium chloride 0.007%. The flow sheet of process pr ocess is given below;

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Process: 1. The Brine is first aerated to remove most of the H 2S. 2. Addition of chloride will remove H2S by displacement reaction. 3. Brine is then pumped to settling tank where it is treated with caustic soda and soda ash to remove

4. 5. 6. 7. 8.

calcium, magnesium magnesium and ferr ic ions. Caustic soda and soda ash ash are blended in the miser to be taken to settling tank. In the Multiple Effect Evaporator (MEE) water is removed and salt crystals are removed as slurry. The slurry is sent to washer, where the salt crystals are washed with fresh brine. The washed slurry is filtered, mother liquor is return to the evaporators and salt crystals from the filter are dried and screened. Salt thus produced from the typical brine is 99.8% purity or even greater. The finest grade (some times made by grinding) is a flour salt, the next coarsest is table salt and finally the i ndustrial ndustrial salt.

The Iodine salt has the following composition; Potassium Iodide (KI) Stabilizer Na2CO3 Sodium Thio Sulphate

: 0.01% : 0.1% : 0.1%

2. From Saturated Saturated Brine by Open Pan P rocess

Process: 1. Salt in the form of hopper-like crystal (grainer salt) is made by causing the salt crystal to form on

the surface of brine held in an open pan. 2. The grainer is a flat open pan 4.5 to 6.0 m width and 45 – 60 m long and about 60cm deep. Beneath the pan steam coils system provided for reciprocating the flakes for salt removal. 0

3. The saturated brine mixed with circulating brine from the grinder is treated to 120 C at which

temperature calcium sulphate is soluble and remove at that temperature. 22/04/09

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4. The precipitated calcium sulphate is removed from gravellier which consist of bed of stones. 5. The purified brine is flash cooled to remove the remaining calcium sulphate. 6. The slurry is then pumped to the grinders where evaporation takes place at 96 0C. 7. A wet salt crystals obtain from the grinder are centrifuged, dried and screened. 8. When the incoming brine has been treated salt of 99.98% sodium chloride can be obtained.

3. From R ock Salt Mining About 35% of salt produced comes from mines of 8 different stages which are operated to produce rock salt. The salt deposits varying color from light reddish brown to half grey. The purity is 98.5%. After the rock is blasted loose they are crushed and then screened at the surface level. The remaining process is the series of grinding, screening to obtain the salft of crystal of various sizes.

4. From Sea Water by Solar Evaporation Annual Annual Evaporat Evaporation ion exceed exceeds s precipit precipitatio ation, n, the statis statistic tics s of 125mm 125mm of rain corresp correspond onding ing to 840mm 840mm evaporation.

By-products of No rmal Salt Salt (also called as value added products) products) Manufacture of sodium sulfates from salt and sulfuric acid 2NaCl + H2SO4 ---> 2HCl + Na2SO4 Na2SO4 + 10H2O -> Na2SO4 + 2HCl HargreavesHargrea ves-Robinson Robinson Pro cess Sulphur Di-oxide, air, steam are passed over specially prepared porous common salt. The reaction is as follows; 2NaCl + SO 2 +

1/2O2

+ H2O ---> Na2SO4 + 2HCl

Bleaching Blea ching Pow der Formulae:

(CaOCl 2).H2O

Equation:

Ca(OH)2 + Cl2 ---> CaOCl 2.H2O

The reaction is a low temperature reaction at 50 OC in a counter current action by passing chorine through a rotating steel cylinder with lifting blades which slower the solid through the path of the gas. When allow to stand in air the bleaching powder absorbs CO2 liberating HOCL (Hypochlorous acid). Other organic acids also liberates same compound. The reactions are, 2CaCl (OCl) + CO 2 + H2O ---> CaCl2 + CaCO3 + 3HClO 2HClO --> 2HCl + O2 After this formation bleaching powder liberates calcium chloride and oxygen. When dissolving in water the reaction gives ionized calcium chloride and hypo chloride. The reaction is, 2CaCl (OCl) --- > 2Ca2+ + 2Cl- + 2OClThe OCl- ion decomposes by liberating oxygen. However the acidity of the product is determined by the % of chlorine in the compound, which is defined as weight of chlorine that will exerts the same action as the chlorine compound compound what we choose. In the case of Bleaching powder, average chlorine is the same as the % of chlorine in the compound. In the case of calcium calcium hypo chloride the % of chlorine is 47.6% if the chlorine content rises to 99.2% in the 22/04/09

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compound. These values are obtained as soon as the freshly prepared compound from the process is finally taken.

Sulfuric Acid Lead Chamber Process Contact Process Lead Chamber Chamber Pro cess

Essentially this process consists of oxidizing a mixture of sulfur dioxide and water to sulfuric acid using nitric oxide as an oxygen carrier. The reaction is, H2O + SO 2 + NO2 ----> H2SO4 + NO This Nitric Oxide (NO) combines combines with oxygen to from nitrogen dioxide which is used again in the process. process. The formation of NO 2 is given by, 2NO + O 2 ----> 2NO2 The process consists of three thr ee stages. The first stage takes place in the Glover tower. This tower is packed with acid resistant bricks over which a cons constant tant stream of sulfuric sulfuric acid made by mixing mixing the output output of lead chambers chambers (65% Acid) Acid) and the Gay-Lusaac Tower (70% Acid) combines with oxides of Nitrogen. Then the hot mixture of SO 2 and Air from the furnace is fed into the base of Glover Tower and comes into intimate contact with the descending acid of low concentration. concentration. Acid results the gases gases from the burners are coo cooled led from 500 0C to about 90 0C and the oxides of nitrogen are extracted from the acid and carried over to the other chambers. In addition the acid undergoes the concentration of 70% by the time it reaches the base of the Glover Tower. Some of the spent spent acid acid after after coming coming from the Glover Glover Tower Tower is also also sold sold comm commerci ercially ally for proce process ssed ed where where that concentrated acid is required. The second stage takes place in the lead chamber from which the process derives its name. Water is spread from the roof on to the mixture of gases are SO 2 and NO2. They slowly react together under carefully controlled conditions of humidity and temperatures producing 65% H 2SO4 which is collected on the shop floor. Lead is used in the material of construction as it is not corroded by acid. The humidity is controll controlled ed by the variations variations in the dry bulb tempera temperature ture and wet bulb tempera temperature ture observed observed in the psychometric chart available in the process plant. The third stage takes place in the Gay-Lusaac Tower which is designed to recover as much as possible of  the Oxides Oxides of Nitrogen Nitrogen from the gases gases leaving leaving to the chamb chambers ers after thoroughly thoroughly washing washing with cold cold 22/04/09

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concentrated acid. The main purpose of this Tower is to minimize the problem of escape of NO 2 to atmosphere. But in the later stages the recovery was more important as the efficiency was high and cost very cheap. A small loss of oxide of nitrogen is inevitable. However it is made good by introducing additional nitric oxide formed by catalytic oxidation of ammonia. This chamber process produces cheap acid of doubtful purity with concentration of 65-80% at maximum. This was used for manufacture manufacture of fertilizers, but where more concentrated concentrated acids are required the contact process is followed.

Contact Pr ocess

Today contact process process is the most widely used process for the manufactur e of H 2SO4 throughout the world. The raw materials used to make sulfuric acid are elemental sulfur, H 2SO4 and H2S. Till 1970, Ion Pyrites and related compounds were the predominant raw materials. The large amount of  sulfuric acid also produced as a by-product of non-ferrous metal smelting. i.e. roasting sulfide ores of  copper, copper, lead, molybdenum, nickel, zinc z inc and some others. The process is dividing to t he following followin g steps; 1. Generation of sulfur dioxide gas 2. Catalytic Oxidation of SO 2 to SO3 3. Absorbing SO3 to form H2SO 4

The reactions are as follows; ---> SO2 1. S + O2 2. SO 2 + ½ O2 ---> SO 3 3. SO 3 + H2O ---> H2SO4

^H = -98KJ ^H = -132.5KJ (Highly Exothermic Reactions)

P roperties of Sulfuric Sulfuric Acid When a dilute solution of sulfuric acid is distilled a constant boiling point mixture is obtained contains 98. 98.3% of H2SO4. This mixtu ixture re boils boils at 338 338 0C and has a dens density ity of 1.84g 1.84gm. m.cm cm-3 is the norma normall concentration concentration acid available available in the laboratory. If the little S O3 is dissolved dissolved in that acid 100% takes acid is obtained and an oily liquid which freezes to crystals of white color at 10 0C. Concentrated sulfuric acid is highly corrosive and should always be handle with care. It causes severe bores when contacted with the skin.

Reactions of Sulfuric Acid 22/04/09

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It is a strong di basic acid reacting to bases to give a series of salts, like sulphates and bisulphates. It is represented by, H2SO4 H+ + HSO4- 2H+ + SO4

2-

The dilute acid reacts reacts with many metals forming forming sulphates and hydrogen. But it does not react with lead, copper, mercury and silver. Iron reacts to give, Fe + H2SO4 ----> FeSO4 + H2^ When the acid highly concentrated attacks any metals forming sulphates and therefore silicon steel is used for construction of distillation column where sulfuric acid is involved. Gold or Platinum have no reaction with H2SO4 whereas copper forms copper copper sulfate with wit h H2SO4 liberating SO2.

Uses Manufacture of Phosphate, Ammonium Sulphate and production of these fertilizers consume about 40% of  total sulfuric acid manufacture. Other large scale users are manufacture of pigments, light barium sulfate, titanium titanium dioxide dioxides s and manufa manufactu cture re of visco viscose se rayon rayon for artificia artificiall silk, silk, deterge detergents nts,, dye-s dye-stuff tuffs, s, drugs, drugs, explosives, plastics, for dissolving unsaturated hydrocarbon during refining of petroleum, for pickling for iron steel (removing (removing oxide layer before before galvanizing) tinning, plating & painting and finally for killing weeds for the agricultural production.

Cement Definition The term “Cement” refers to many different kinds of substances that are used as binders or adhesives. It refers to inorganic inorganic hydraulic cements cements (mostly (mostly called called as Portland Portland cement) cement) which which are hydratio hydration n form relatively relatively insolub insoluble le water water bonde bonded d aggreg aggregatio ation n of high streng strength th and dimens dimensiona ionall stab stability. ility. In the last last century century it has been found found that iron in comb combinati ination on with with ceme cement nt has proved proved subst substanti antially ally the useful concrete for very high-rise buildings and massive constructions. Hydraulic cements also manufactured by process processing ing and proportionate proportionate raw materials materials burning (clinkering) at a particular particular temperature temperature and grinding the resultant product to obtain the cement. The cement consist mainly tri-calcium silicate and di-calcium silicates. The raw material are lime stone rich in calcium and silica such as clay or shale. Clinker Formation Portland cements are manufactured from raw mixes including components such as calcium carbonate, clay or shale and sand. When the temperature temperature of materials increases during during the passag passage e in the rotary kiln the following reactions occur; 1. 2. 3. 4. 5.

Evaporation of free water Release of combined water from the clay Decomposition Decomposition of magnesium carbonate Decomposition Decomposition of calcium carbonate Combination of lime and clay oxides

Finally cooling is done to maintain the phase equilibrium. Manufacturing Processes Wet process and Dry process plants produced Portland cement. It consist of quarrying and crushing the rock, including control of the clinker composition by systematic core drillings and selective quarrying. The next process is grinding the proportioned materials to high fineness. Ball Mills are used for the both the process to grind the material although roll crushers are used for dry process. The high tempera temperature ture of operat operation ion vaporizes vaporizes the alkalies alkalies,, sulphur sulphur and halides (rotary (rotary kilns for Wet proces process, s, Dry proces process s , suspens suspension ion free heaters heaters or precalc precalciners iners). ). The grinding grinding is done done by open open circuit circuit grinding or closed circuit grinding depending on the fine powder of cement required. Manufacturing Manufa cturing procedures (W et & Dry processes) 22/04/09

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The Wet Process is the original one is being displaced by Dry Process for few factories because of saving energy, accurate control and proper mixing of the raw material. The dry process plants account for 58% of  the total amount manufactured with full production capacity. It is illustrated in the following flow chart.

In the wet process the solid materials after dry crushing is reduced to fine powder in wet tube or ball mills and passes passes as slurry through bowl classifiers classifiers or screens. screens. The slurry is pumped to connecting tanks where rotating arms takes the mixture homogeneous and allow the final adjustment in composition. For this purpose some of the cement plant the slurry is filtered in a continuous rotary filter and fed into the kiln. The dry process is especially applicable to natural amount rock and to mixtures of limestone, clay, shaves as slate. In this process process the materials are crushed crushed roughly are passed passed through gyratory gyratory or hammer hammer mills, dried, sized, finally grounded followed by air separation or the pneumatic process. Before entering the rotary kiln thorough mixing and blending takes place. The rotary kiln where the powd powder er materia materiall is fed the chemic chemical al reactions reactions takes takes place. place. Heat is provide provided d by burning burning of oil, gas or pulverized coal using preheated air obtained from cooling of the clinker from the high temperature to lower temperature. temperature. And the l ength of the rotary kiln is increased the thermal thermal efficiency very high. Due to this process of heat transfer vaporization efficiency also increases because of evaporation of moisture and water in the mix. Normally the vaporization efficiency is twice the thermal efficiency for the process of  conduction into material. Dry process kilns are 150 ft long but the wet process over 500 ft kilns is quite common. The internal diameter is around 20 ft. The RPM is ½ to 2 depends on the size. The kilns are inclined so that materials fed at the upper end travel slowly to the lower firing end (by blower) and taking 3 hours to reach he bottom end. To improve the economy of kiln heat water is removed from the wet slurry before charging into kiln. Some of the equip equipme ments nts are empl employ oyed ed slurry slurry filters filters and ‘Dorr ‘Dorr Thic Thicken keners ers’. ’. Effic Efficient ient air pollut pollution ion control ontrol equipm equipment ent such such as bag bag houses houses or electros electrostat tatic ic precipit precipitato ators rs are required required for the proce process ss.. Waste Waste heat boilers boilers are somet sometime imes s used used to conse conserve rve heat and partic particularly ularly econom economica icall for dry proce process ss cement. cement. A refractory lining is given inside wall to protect the heat form escaping outside and maintain a temperature of 800 OC. In the recent days computers are used to improve kiln control. The sketch of rotary kiln is given below; 22/04/09

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The final product form consists of hard granular masses of ¾ of the inch in size called clinker. It is discharged form the rotating kiln into air-quenching coolers which brings the temperature to 100 0C. The cooling also preheat the combustion air pulverizing followed by grinding in the tube or ball mills and automatic packaging complete the process. process. There are many types of compounds in cements according to the composition numbering 102 types of  cements according to the applications. Special cements also manufactured for corrosive conditions and the various various types types of sulphur sulphur ceme cements nts,, silicate silicate cements cements,, adhes adhesive ive cemen cements ts to have a few. few. The industrial industrial importance sulphur cement are resistant to solves acids, alkalis, oil, grease or other solvents. These are employed for the joining of Tiles and Cast Iron Pipes. Silicate cements with stand a temperature of 1000 0 F.

Glass & Ce Ceramics ramics Glass Glass was formed formed naturally from common common elements in the earth dust long before anyone ever thought of  experimentally experimentally with this composition, composition, moulding moulding its shape of putting it to the myriad of used that it enjoys the world today. Glass technology evolved around 6000 years back and sum of the today’s principles followed the old times. This includes what is today known about the structure of glass, its composition, properties, method of  manufacture and uses. The term glass follows the definition of MOREY, ‘GLASS is an inorganic substance in a condition that is continuous and analogous to the liquid state of the substance. But which as a result of a reversible change in viscosity during cooling, has obtain so high a degree of viscosity has to be for all practical rigid’.

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Most glass Most glass partic particles les are manuf manufac actur tured ed by a proce proces ss in whic which h raw mater material ial are conve converte rted d at high high temperature to a homogenous melt that is then formed into various articles or glass wares employed in laboratories. The above flow diagram summarizes the details of conventional glass manufacturing. The vapor deposition of SiO2 from a flame fed with silicon chloride (SiCl 4) and oxygen is basis for manufacturing high purity glass used for blanks that are redrawn into optical-wave guide fibers. Fused silica items that cannot be formed from viscous melts of SiO 2 or Quartz are prepared by vapor deposition. Raw materials are selected according to purity, supply, pollution, potential, ease of melting and cost. Sand is the most common ingredient. Limestone is the source of calcium and magnesium. The reducing agent is powdered anthracite and common colorness for glass includes Iron, chromium, cerium, cobalt and nickel. Melting and fining depend on the batch materials interactive with each other at proper time and on the proper order. Thus the stream must be taken to obtain materials of optimum grain size, to weigh them carefully and mix intimately. The efficiency efficiency of the melting operation and the uni formity and quality of the glass product are determined in the mixing house. Batch handling systems are widely used in the industry from manual to fully automatic small furnaces for annual production to large continuous tank for rapid machine forming. The two important equipments are screw screw feeder feeder and recipro r eciprocating cating pusher. Control devices devices have advanced advanced computer computer ass assistant istant operations. Radiation pyrometer with thermocouples monitor furnace temperature. Natural gas, oil, electricity are the primary source of energy and propane is used as a backup reserve for emergency. Molten glass is molded, drawn, rolled and quenched depending on the desired shape and use. Bottles, dishes, optical lenses, helix picture tubes are formed by blowing, pressing, casting and filling the glass against mould and cool it to get the desired shape. 22/04/09

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Art glass is made manually and an glass called FRIT is obtained by powdered glass and quench between water cooled rollers, poured into water and then dried. Glass optical formed as high temperature must be cooled in order to reduce its strain and associated stress caused by temperature gradient. The following are the types of glasses; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Flint Glass Bottle Glass Pyrex Glass Photosensitive Glass Froast Glass Ground Glass Insulating Glass Vitreosil Glass (99.9% Silica) Fused Silica Glass Optical Glass Lead Glass Colored Glass Opal Glass Fiber Glass Safety Glass and Glass Wool

Ceramics W hite Waxes Waxes White wax is a generic term for ceramic products which are usually white and of fine texture. These are base based d on selec selectiv tive e grad grades es of clay clay bond bonded ed toge togethe therr with with varyin varying g mount mount of fluxes fluxes and heated heated to a 0 moderately high temperature in kiln of 1200-1500 C. Because of the different amounts and kinds of  waxes there is a variation in the degree of vitrification. Among white wax, from earthenware to vitrified china the degree of vitrification is the progressive reduction in porosity provides the basis for the useful classification of ceramic products as follows; fol lows; Earthen w are – some times called as semi vitreous thinner ware is porous, non translucent with a 1. Earthen 2. 3. 4. 5. 6.

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soft glaze. China w are – a vitrified translucent ware with a medium glaze which resist abrasion to degree which is used for non-technical purposes. Porcelain – a vitrified translucent ware with a hot glaze which resist abrasion at maximum degree. It includes chemical, insulating and dental porcelain. Stone Stone w are – one of the oldest ceramic products developed and rewarded as throughout porcelain. Sanitary Sa nitary w are – formed from clay is porous and preferred for vitreous application with a tri-axial composition. White ware – white ware tiles available in number of times, classified as floor tiles, resistant to abrasion and impervious to stain stain penetration penetrati on and used as wall tiles of a variety of colors colors and is formed small surface.

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To represent a typical manufacturing procedure in the ceramic group, porcelain is chosen below. There are three lines of production. Wet process porcelain – used for production of fine grained, highly glazed insulators for high voltage application and cast porcelain necessary for making pieces to large are too intricate for the other two methods. The 3 processes are based on the same raw materials. The difference in manufacture is the drying and forming steps.

Description Descript ion of P rocess Raw material of proper proportions and properties to furnish porcelain porcelain of the desired quality are weighed from from overh overhea ead d into the weigh weighing ing car. Feldsp Feldspar ar clays lays and flint are mixed mixed with water water in the blend blender er (clay-water mixture) and then passed over a magnetic separator, screen and store. Most of the water is removed by by filtration. All the air is removed by the mill with the help of vacuum operation. This This produces produces stronger or hard porcelain. The prepared clay is formed into blanks and hot pressed suitably. They are then dried, dried, trimme trimmed d and finally comp completely letely dried all under under carefully carefully controlle controlled d condit conditions ions.. The hydro hydro separator separator removes the water and moisture moisture containing containing i mpurities. mpurities. The vitrification vitrification is carried out in ‘tunnel kilns’ at a particular temperature and then porcelain articles are protected by Saggers fitted in the final stage of the process. The glazing and firing are simultaneously done to obtain lustre or shiny nature of the porcelain. They are immediately tested for electrical insulation after storage for sale. The table-ware is manufactured by more complicated procedure then illustrated by the porcelain process. Some objects are obtained by the porcelain process. Some objects are obtained by the potter’s wheel in the conventional cottage industry employed in rural areas. For separate application, complex shapes for chemical laboratories are manufactured by different mould for the required applications. Glazing is an important process process in the manufacture manufacture of white wax. Some times a glaze is a thin coa coating ting of  glass melted on the porcelain surface for porous application. The chemicals used are soda ash, potash, fluorspar, borax for this type of special application. The temperatures for glazing is around 1050-1500 0C.

Refractory and colorants for ceramics It is broadly divided into two groups; one for clay based products like tiles, sanitary wares and thinner ware and the other based on silica as a major ingredient. In the manufacture of glasses continuous for laboratory conditions at normal temperature and pressure color is obtained by a suspension of the coloring medium when final stages of the product obtained.

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Pulp and P aper Industry The transmission of thought my means symbols was practiced thousands of years back, prior to Christian era. Primitive people used to stores clay, palm leaves, shells and bark of plants are which to inscribe information. Egypt is the country where origin of paper took place, now there is no production in that country of paper. On the other hand in china about 200 B.C. the paper was manufactured and now the forerunner of the industry. Raw Materia Materials ls The raw materials employed in the pulp and paper industry are woods, rags, straws, bagasse, sulfur, limestone, alum, soda ash and clay. The only country to have all the above raw material within the country is USA. 1. W ood It is the outstanding source of cellulose in fact more than 90% of the paper consumed in the world is made from wood fiber. Again U.S. has the abundances of wood excepting excepting Russia. The North American continent process pr ocesses es 40% of soft wood. 2. Fibrous Raw Materials Since 1800 where wood was first employed intensively for the manufacture of pulp no other alternative has append so for. For this thi s purpose the reuse reu se of waste paper become become dominant and contri butes 1/3 of total production. 3. Non-Fibro us Raw M aterials The important material here is sulfur about 200,000 tones of sulfur has produced for paper production. The other materials caustic soda, soda soda ash, rosins and bleaching components, lime is employed for sulfi te cooking process. process. The mineral miner al substances such such as clay, talk, chalk, barites, bari tes, zinc compounds and titanium compounds compounds are used for manufacture manufactur e of paper as non-fibrous materi als. Manufacture of Pulp lp : 1. W o o d P u lp

The process is employed in the preparation of pulp from wood are mechanical (ground wood) and chemical (sulfite, sulfate & soda) and a combination combination of mechanical and chemical known as semi-chemical. The object of the formation of pul p is to separate the wood into fibers. The original wood contains 50% of non-fibrous material like lignin and inorganic matter. Mechanical P ulp: This mechanical or groun d wood process process is used largely on coniferous wood 2. Mechanical (having the name from coniferous forest past). Especially with low rosin content such as spruce, balsam and hemlock, jack pine is used to produce pitchy har d wood. This mechanical mechanical pulp pul p used for newsprint, wallpaper, wallboards and paper boards. It is sometimes mixed mixed with chemical pulp. Chemical Pulp : It is a material which made after treating the wood by chemical which remove the 3. Chemical cementing material, for this pulp the wood is cleaned thoroughly from bark & knots. The logs of  woods are conveyed to the chipper where they are forced at an acute angle against a disc on the surface above which heavy knives are operated on. The chipping operation produces pieces of wood of various sizes siz es and then classified as saw dust.

Sulfite P rocess: H2O + SO 2 -----> H2SO3 Ca(OH)2 + 2H2SO3 -----> CaCO3 + 2H2SO3 ---->

Ca(HSO3) + 2H2O

Ca(HSO3)2 + H2O + CO2

Sulfur is melted and then burned into Sulfur Di-oxide (SO 2) in special rotary burners where the supply of  air is regulated to prevent the formation of objectionable SO 2. The gas is cooled in water immersed pipes after which it is absorbed by; 1. Large absorbers containing milk of lime 2. Through tall towers made of concrete packed with limestone over which water trickles down.

The sulfite pulp is used for wide application in newsprints, boards, wrapping papers and certain grades of  printing papers where reasonably light color and good strength are required. Bleach Bleach sulfite sulfite paper paper is used used in writing, writing, typing paper, paper, tissue tissues, s, grease grease proof proof papers papers and high grades grades of  wrapping paper. 22/04/09

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Sulfate Sulfa te Pro cess: It derives the name from fact that loss of alkali and sulfur is compensated by sodium sulfate (salt cake) or its equivalent. The term KRAFT means strong and applied to pulp prepared by this process for producing the strong pulp. The raw materials used are southern pine, spruce, jack pine, and tamarack. This is followed followed by coo cooking king the chips and then washing washing followed by recovery of sulfate liquor. The main reaction is; Na2SO4 + 4C ---> Na2S + 4CO Analysis of solids in sulfate process; So l i d s

O r i g i n al s m e l t ( % )

Gr e e n l i q u o r ( % )

W hi te l i q uo r ( % )

Na2CO3

61

64

11

Na2SO4

4

5

6

Na2S

27

31

22

NaOH

-

-

61

Silica

2

-

-

Insoluble

6

-

-

Apart from the above processes there are miscellaneous processes like soda process, semi chemical pulp process and rag pulp pul p process. Grades of Paper There are number of method by which paper may be classified; 1. By the type of furnish process in the paper manufacture. Eg. Sulfite process 2. By the property. Eg. Grease proof paper, absorbent paper. 3. By the use to which it’s applied. Eg. Newsprint paper.

Tissue: It is the lightest weight paper. Generally grade on a Yankee machine like napkins, light weight wrappings and toilet papers. Wrapping: Bags, envelopes and bread wrappers Writing: Stationary, ledger, document and type writing sheets belongs to this category Printing: Newsprint, catalogue and bible papers Books: Books & Magazines Building: Papers mixed with asbestos employed employed in construction work, sheathin g papers, felting papers, dead ending felts for acoustic properties involves and floors the auditorium. Boards: By far the largest production of the industry falls in this class. The subdivisions are numerous li ke containers, container s, binders, bottle caps, chips chips and wall boards. Research The application of science and engineering in pulp and paper manufacture are brought about to improve operation and progress in the manufacture for better products and also the reduction in prices. Consumption Paper products and the related chemical are important to a developing nation such as India, the per capita consumption of paper is the measure of the educational, social, cultural and industrial activities of the country as given below;

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Co u n t r y

Co n s u m p t i o n ( Kg Kg / P er e r s o n / Y ea e ar )

USA

206

UK

167

Japan

57

USSR

16

India

1.5

The end use distribution of paper is given below; En d Use

Di s tri b uti o n ( % )

Paper & Paper Head

65

Newsprint

20

Rayon (Chemical pulp)

15

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TOPI C 3: OIL, SOAP SOAP & DETE DETERGE RGENT, NT, PETROLEUM REFI NI NG, P ETROC ETROCHEMI HEMI CALS AND SU SUGAR GAR Hydro genation of Oils Large amount of groundnut oil, cotton seed oil, etc are hydrogenated in presence of suitable catalyst to obtain solid edible fat called vegetable ghee. The purpose of hydrogenation is to increase the melting point of oil and convert in to an edible fat. In other words, hydrogenation are hardening of oil is a process in which various unsaturated radicals are converted into completely saturated Glycerides. There fore the hydrogen plays an important role in the process with a catalyst. The process is carried out by keeping the oil at a temperature temperature of 140-180 0C contain containing ing finely divided divided liquor in suspen suspensio sion n by the subse subseque quent nt absorption of Hydrogen. Optimum conditions for the Process ne eded can be manufactured by a number of methods but hydro carbon steam process 1. The Hydrogen needed has been widely used. The hydrogen must be very pure. Traces of gaseous sulfur compound, H2S, SO2, Arsenic and Chlorine compounds are strong catalyst poisons. These have to be removed before the hydrogenation process. 2. The oil must be pure as well as free from fatty acids. Fatty acids react with Nickel and its oxides to form Nickel Soap which is soluble in oil. For purification, the oil is taken in a tank fitted with steam coil are heated to 30 0C. Then caustic soda is added and mixture is agitated for about 20 minutes min utes by compressed air. The moisture is removed by heating the oil in vacuum. The moisture may be hydrolyses the oil at high temperature and pressure to form fatty acid. 3. In order to prevent the ‘Pyrophoric Nickel’ from catching fire the Nickel catalyst is carefully transferred to the oil out of the contact with air. 4. In order to keep the Nickel particles in free suspension and to bring the oil in close contact with Hydrogen, the mixture of oil catalyst and Hydrogen is agitated. 22/04/09

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5. The catalyst is Nickel Oxide or Nickel Formate which is reduced to metal by Hydrogen gas are forms

 ‘Raney Nickel’. The charge is kept at maximum temperature for about one hour and then cooled. During the cooling period the Hydrogen is passed to create the product hydrogenated oil stored in the end of the process.

Recent research has shown that Palladium has been found to be more effective then Nickel. i.e. 1 part in 1,000,000 parts of oil is sufficient. And the reaction takes place at lower temperature and takes less time. The only disadvantage is Palladium is costlier than Nickel, Raney Nickel and other catalyst. The process of Hydrogenation is exothermic reaction. There fore it is favored by low temperature. The optimum temperature is around 150 0C. Apart from the above there are two processes of Hydrogenation of oil 1. Dry Process 2. Wet Process 1. Dry Pr ocess The refined oil from the storage storage tank i s brought into a vacuum evaporator evaporator where it is heated at about 50 0 C at low pressure pressure in order to expel air moisture. moisture. By means of the pump the oil is charged into convertor convertor by pipe provided at the bottom of the evaporator. The convertor is a cylindrical pressure vessel provided with Hydrogen distributor. In the bottom steam coils for heating and circulating the oil. The Hydrogen gas is sent at a pressure of 5.6 atm. into the convertor. The steam is turned off to accelerate exothermic reaction and convert the oil into a hydrogenated substance for further purification process. For the commercial value Bleaching is done for aesthetic consideration for the market value. 2. W et Process In wet proce process ss Nickel Nickel salt salt is r educe educed d into finely divided divided Nickel Nickel in the oil before before hydrogenat hydrogenation ion in a continuous process. There are two wet process are employed, in one process Nickel Formate is used and the reduction is carried out at 190 0C with Hydrogen.

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The advantage in this first method of the wet process is removal of CO as waste removed from Deodorizer still as Co is a catalyst poison for the Nickel group. In the seco second nd method method 2% Dry Dry Nicke Nickell Forma Formate te in powd powder er form form is mixed mixed with with 100 Kg of Oil to be 0 hydrogenated hydrogenated as a current of Hydrogen is passed passed at a temperature of 250 C. The pressure is 10-12atm. 10-12atm. Introduced Introduced by nozzles to the convertor. convertor. After the r eaction eaction is i s completes, completes, the temperature is brought down and ascertained the completion of hydrogenation. There are ar e two important advantages of this process; More active catalyst having high surface area is obtained because the reduction of salt is carried out at low temperature. Nickel does not come into contact with air at any stage and hence fire hazard is avoided. Margarine Hardened oils are consumed as such as in India, but in Europe and America they are converted to a butter called ‘Margarine’. It is prepared by emulsifying about 80% fat and 15% skimmed milk, salt, vitamin A, vitamin D, a preservative such as sodium benzoate, a yellow dye and flavoring agents.

Soap Making Industry Raw Materia Materials ls 1. Source of Glycerides: The main sources of slow lathering hard oils are tallow, palm oil, whale oil, fish oil and greases, etc. Quick lathering hard oils include coconut oil, palm oil and kernel oil, etc. Soft oils are soya bean oil, cotton seed oil and inedible olive oil, etc. 2.Rosin: A plant product contains mainly abietic acid. The colorless variety of Rosin is used in the manufacture manufacture of laundry soaps and dark variety is used in the manufacture of colored soaps. soaps. Rosin makes makes lather formation faster, increases the cleaning property of the soap and softens the hard soaps. Rosin requirement is about 50% and the grease is 23%. 3. Caustic Caustic Soda: It is available in the form of flakes, blocks and sticks as well as in solution of sodium hydroxide in various concentrations. The caustic product potash is involved in the manufacture of saving creams. 4. Sodium Sodium Chloride: Sodium Chloride is used for salting out about 12.5 parts per 100 parts of oil to be saponify is used. 5. Binding Materials: Sodium Silicate, Soda Ash, Tri Sodium Phosphate, Borax are used as Binding materials. They improve the soap texture and prevent the formation of precipitate in hard water. 6. Fillers: The weight of the Soap is determined by fillers such as talc, starch, glauber salt, pearl ash, etc without affecting the detergency of the washing soaps. 7. Colour Colour ing M atter: 22/04/09

Organic dyes and inorganic pigments are used. As a Dye the material should www.sdsenthil.com

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be inert to alkali used in making soap and should not separate when soap is blended in the process. Common coloring matters are methyl violet, Bismarck brown, safframine for red, zinc oxide for white color, chrome green for green color, cadmium for yellow color, ultra marine for blue color, eosin for pink color, vermilon for rose shade. Intermediate colors are obtained by blending the above colors. 8. Perfumes & Perfume Fixatives: Fixatives: These impart fragrance for the soap. They may be natural or synthet synthetic. ic. Examples Examples are sanda sandalwo lwood od oil, lemon lemon grass grass oil, clo clove ve oil, eucalyp eucalyptus tus oil, lavender lavender oil and cinnamon oil, etc. The synthetic perfumes are, Jasmine (Benzyl Acetate) Rose (Phenyl Ethyl Alcohol) Lylac (Terpenol) Musk (Benzoate)

Manufacture of Soap Soap is either Soap either made made by hot proce proces ss or cold cold proc proces ess. s. Usual Usually ly laund laundry ry soap soaps s and bath bath soap soaps s are manufactured by hot process. Transparent and other special types of soaps are produced by cold process. In most most of the case cases s soap soap obta obtained ined by hot proc proces ess s settl settled ed and and sepa separat rated ed from from Glycero Glyceroll solut solution ion.. Subsequently Glycerol G lycerol is separated out as a by-product. The hot process is divided into tow types, 1. Batch Process 2. Continuous Process

The Batch Process is carried out in a soap kettle made of steel plates and having large diameter. The kettle is supplied with steam with a mixture of melted fats, grease, oil in a proper amount for the mixture. The amount of caustic soda is regulated to undergo the hydrolysis reaction. The boiling is continued until the saponification is completes. A pasting mass is formed by conversion of Tri-stearin to Di-stearin. The final product contains soaps, water, glycerol, unused alkalis, sodium chloride, sodium carbonate, sodium sulfate as impurities. After this saponification is complete and the steam is cut off with the separation of salt on the surface for the batch process to stop and deliver th e soap product.

In the Continuous Process the raw materials oils and fats and the catalyst usually zinc oxide are blended and fed into a hydrolyser or splitting tower fitted with steam coils through which steam is passed for heating the charge. The splitting of fat takes place continuously in a counter current manner and about 22/04/09

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250 0C and 40 atm pressure. The fat raises again the aqueous phase which also dissolves glycerol in reaction. reaction. The fatty acids acids are discharged discharged from the hydrolyser hydrolyser to a flash tank called decanter decanter where excess excess of water is separated. They fatty acids are the passed to a heat exchanger and then to a vacuum still and distilled. The distillate is collected as overhead and bottoms are stored for recovery. Then the distillate neutralized by caustic soda in a continuous neutralizer. As the result of this soap is obtained which is with drawn hot into a agitator agitator tank. This soap contains contains Water, NaOH and NaCl. This is dried in a high pressure pressure steam exchanger by heat and pressure, finally collected in a flash tank. The pasty mass is missed with air and cooled to 65 0C. Here the soap is continuously extracted and collected into soap frames where it solidifies solidifies on coo cooling. ling. Then i t is cut into bars as usual. The particular process process delivers the product product in a day whereas the batch process operates operates for few more days.

Petroleum Refinin Refining g Cracking Cracking is the process by virtue of which crude petroleum of their fractions are decomposed by heat to produce products which have lower boiling points. The main object of cracking is mainly the production of  gasoline. The two types of cracking are, 1. Thermal Cracking 2. Catalytic Cracking

1. Ther mal Cracking The main reaction is C 10H22 --Cracking -->C6H12 + C6H10 Paraffin+Olefin The crude petroleum is heated to 1000 0F in a pipe heater. A pressure of 1000 psi is maintained and the lower molecules are ar e further furth er decomposed as as below; CH4 ---Decompose -->C + 2H2 Gas and Gasoline in vapor form go out as two products. The vapor phase is condensed to obtain Diesel, Petrol and then LPG in the bottling plant to serve energy requirements. The coke coke deposited deposited in the process is remov removed ed perio periodi dica cally lly and the proc proces ess s whic which h is a continuo ontinuous us one is sust sustain aining ing for for the vario various us fractionation products. The various other forms of thermal cracking are as follows; i. Viscosity Breaking ii. Vapor Pressure Cracking iii. Thermal Reforming i. Viscosity Breaking: Breaking: Here various various oils and residues residues obtained obtained after after thermal thermal crackin cracking g are to produce produce various oils of different different viscosity. viscosity. This is called as Viscosity Viscosity Breaking. The temperature temperature is 460 0C and pressure is 500 psi. ii. Vapor Vapor P ressure Cracking: Here Cracking is done in such a way there is only vapor phase obtained after cracking. By doing so aromatic hydrocarbon and gaseous products are obtained. iii. Thermal Reforming: Here heavy gasoline of lower octane number is cracked to get higher gasoline of higher octane number. The temperature is 530 0C and pressure is 750 psi. The flow sheet of Thermal Reforming is given below;

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2. Catalytic Catalytic Crackin g Gasoline produced by Thermal Cracking has octane number 72. If the octane number is increased the yield decr decrea ease ses s whic which h can can be rectif rectified ied by use use of cata catalys lystt to increa increase se the rate rate of deco decomp mpos ositi ition on of the hydrocarbons in the crude petroleum. Hence gasoline produced by catalytic cracking is low in oliefic and high in paraffinic and aromatic hydrocarbon. The advantages of catalytic cracking are, 1. 2. 3. 4. 5. 6.

No fuel from outside is required for catalytic cracking All the heat required is obtained by heating the coke deposition the catalyst The pressure is low The Gasoline has a high octane number Total yield of Gasoline is high A sulfur content of all the products is low as it is eliminated as H 2S.

Types o f Catalytic Catalytic Cracking The two types of Catalytic Cracking are, 1. Fixed Bed Catalytic Cracking 2. Moving Bed Catalytic Cracking

The first one is a catalytic catalytic cracking cracking where fixed bed of catalyst is used. The catalyst in a form of granules or pellets and bed of the catalyst for fixed in the catalyst covers. Oil vapors which are heated to the cracking temperature through the catalyst are carbonized at which it is reactivated by burning the carbon. Oil vapors are diverted tot eh second catalyst chamber. Second one is a catalytic cracking where moving bed of catalyst is used. The catalyst in the form of fine powder flows down through a hopper into a reactor where cracking takes place. The carbonized particles of  the catalyst come down against a raising current of air to remove the carbon deposit of the catalyst as it is burnt off.

1. Fixed Bed Catalytic Catalytic Cracking Pr ocess The fixed bed catalytic cracking method is described in the following diagram.

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The charge is passed through a heater where it is heated to cracking level then it is goes to catalyst towers. These towers have catalyst tubes and around these tubes molten salt mixtures (mixture of sodium nitrate and sodium nitrite) are circulated to distribute heat and maintain uniform temperature in the reactor. The cracked vapors form these catalyst towers of fractionators in the fractionating column to recover gases and gasoline vapors from the top and the heavy gas/oil is removed from the bottom of the column. Gasoline Gasoline vapors vapors are cooled cooled and condens condensed ed in the conde condense nserr and then sent sent to the stab stabilizer. ilizer. In the stab stabilizer ilizer certain certain disso dissolved lved gases gases are removed removed and the desired desired boiling boiling range range and vapor vapor pressure pressure is obtained. The main catalysts used are 1. Bauxite pellets 2. Silicon Nitrite complex of Alumina (SiN 2.Al2O3) of 6 mesh size

2. Moving Bed Catalytic Catalytic Cracking Pr ocess The moving bed catalytic cracking method is described in the following diagram.

Heated oil vapors go up in the reactor and catalyst comes down through the hopper which is the significance in the moving bed catalytic cracking process. After the cracking of vapors the spent catalyst is removed from the bottom. It is regenerated and sent again to the catalyst hopper through the elevators. The cracked vapors after the separation of dust separated go to the fractionator where gas oil is separated from vapors of gas and gasoline. gasoline. Gas G as oil is with drawn from the bottom. The gas and the gasoline gasoline vapors 22/04/09

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are condensed in the condenser and are separated. Other methods of synthesis of gasoline are by polymerization, alkylation, Fischer-Tropsch method and liquefaction of coal or hydrogenation of coal. Normally the gases obtained from the cracking of petroleum are ethylene, propene, butene and saturated hydrocarbons like methane, ethane, propane and butane. Polymerization also classified by catalysis to obtain motor fuel.

Petrochemicals Petroleum & Petrochemical Petrochemical I ndustries ndustries Crude Oil Refining

Petrochemical Products

Composition 1. Aliphatic Compounds are classified into n-paraffins of the formula C nH2n+2 Eg. Hexane & Heptane.

The other is iso-paraffins of the formula C nH2n+2 Eg. 2-methyl hexane, a derivative of the paraffin indicated above. 2. Cyclic Compo Compo unds of the formula CnH2n Eg. Napthene and Benzene series of the formula C nH2n-6 Eg. BTX 3. Asphalts contain atoms of carbon, hydrogen, sulfur, oxygen and nitrogen. Various resins are used as adhesives which are semi solids in structure. The crude is classified into paraffinic base for aliphatic compounds, naphthenic base for cyclic compounds and an intermediate base for both of the above.

The petroleum refinery products are classified as; 1. 2. 3. 4. 5.

Gas Fraction – Eg. Natural Gas, whose main composition is methane and the second one is LPG Light Distillates – Eg. Petroleum & Kersosene Intermediate Distillates – Eg. Diesel Heavy Distillates – Eg. Wax & Lubricating Oil Residue – Eg. Grease & Asphalt

The normal r efinery processes processes for the manufacture manufacture of various products products are done by physical physical changes changes like distillation, distillation, absorption, absorption, extraction, adsorption, adsorption, crystallization, crystallization, heat transfer transfer and fluid flow to name a few. Simila Similarly rly the unit proc proces esse ses s involv involving ing chem chemic ical al chang changes es are pyroly pyrolysi sis, s, reform reforming ing,, polym polymeriz erizat ation ion,, alkylation, isomerisation, sulfur removal, hydrogenation, etc. Lighter most most products

–----> Methane -------> Methanol, Chloromethane

Naphtha ---Steam/Cracking---> Ethylene Ethyle ne ----> Ethyl Oxide, Acetaldehyde Propylene ---> Iso-propanol, Iso-propanol, Cumene, Polypropylene Polypropyl ene C4, C5 Series

----------- >

Hydrocarbons --Reforming-->

Butane -----> Butadiene B enzene ----> Ethyl Benzene, Maleic Anhydride T oluene -----> Nitro Toluene, Phenol X ylene ------ > Phthalic Anhydride, Terephthalic Acid

Manufacture of Chloromethane Methane Methane on chlorinatio chlorination n yields yields succes successf sfully ully the chlorom chlorometha ethane ne by subst substitutio itution n of hydrog hydrogen en ato atoms ms by chlorine. The flow sheet of the industrial manufacture is given below; 22/04/09

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Reactions CH4+Cl2 --> CH3Cl+HCl -–Cl2--> CH2Cl2+HCl -– Cl2--> CHCl3+HCl ---Cl2--> CCl4+HCl Methane

Methyl Chloride

Methylene Chloride

Chloroform

CTC

These compounds of the chlorination reaction are used as industrial solvents and intermediates in the manufa manufact cture ure of organic organic comp compound ounds s for dye and dyestu dyestuffs ffs manufact manufacturing uring plants plants.. Similarly Similarly we have production of ethylene oxide in a fluidized bed reactor to produce the product and used for manufacture of  ethylene glycol. The reaction is exothermic and the heat generated may be used for other purposes like heat exchangers of the type of shell & tube, etc. Acetaldehyde manufactured from ethylene by exothermic react reaction ion with with palla palladi dium um chlor chlorid ide e cata catalys lystt in a series series of strip strippe pers rs and and dist distilla illatio tion n colum columns ns for for the manufacture. Isopropyl alcohol is manufactured from propylene by reaction with industrial acids to form the product. Cumene is another petrochemical manufactured from benzene by packed bed staged reactor at a temperature of 250 OC in i n the presence of phosphoric phosphoric acid. acid. Butadiene is another compound compound obtained obtained from C4H10 to produce finally styrene and rubber for the polymer polymer industry. Phthalic anhydride anhydride and maleic anhydride are produced from tubular reactor by the production of isomers and dehydration reaction to form compo compound und polyes polyesters ters.. Phenol Phenol is a very importa important nt comp compound ound obtained obtained from from Toluene Toluene by series series of  distillat distillation ion column column and used used in the manufa manufact cture ure of phenolphenol-form formald aldehyd ehyde e resins, resins, molding molding produc products ts,, electrical applications and other various uses in the polymer industries.

Petrochemical Petrochemical I ndustry in India It is still in a incipient state born born much later than petroleum industry industry around 1966, the growth it made in the the las last two two year years s becau ecaus se of tec technol hnolog ogy y is very very much uch enc encou oura ragi ging ng.. The The modes odestt beginn eginning ing of  22/04/09

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petrochemical industry started with coming of an ethylene plant of capacity 20,000 TPA by a naphtha crac cracker ker by Union Union Carb Carbid ide e in 1968. 1968. Natio National nal Organi Organic c Chemi Chemica cals ls Limite Limited d (NOC (NOCIL IL)) soon soon follo followe wed d the development development and established established 60,000 TPA naphtha cracker cracker units at Thane in Maharashtra Maharashtra by 1968. Indian Petrochemic Petrochemical al Limited (IPCL) (IPCL) in Baroda in the year 1971, with an investment investment of 1 000 crores of rupees to estab establish lish a crack cracker er unit indigenou indigenously sly.. Subseq Subsequently uently ONGC which which was responsib responsible le for explorat exploration ion and production of Oil and Natural Gas made an active role in the aromatic ester plant by the side of Gujarat Refinery. The development of IPCL fulfills the growth of 32 complexes all over India for the expansion of petro products products.. By eighth plant Rs. 5000 crores was exclusively exclusively invested by IPCL for the growth growth of engineering plast plastics ics.. The produc products ts like alloys alloys,, poly poly carbo carbonate nates, s, carbo carbon n filaments filaments,, oil blends blends and other other polyes polyester ter products where diversified by the various companies listed above.

Sugar Indu stry Today Sugar is so plentiful and so cheap that we take it granted and overlook how much science and industry accomplished in making refined sugar available to us. Primitive man had to depend on roots, fruits and saps from certain trees for any sweetness for his diet. The term sugar refers the chemical sucrose. Sources of Sugar Cane : It was first cultivated in India from where it spread eastward to China, westward to 1. Sugar Cane: Arabia, Egypt, Spain and finally to the new world. The sugarcane (saccharim officinaram) is a tall perennial grass having numerous bamboos like stems which grow to a height of 12 feet or more. The period of growth is normally 15-18 months, but because of the advent of the fertilizers the period shortened and a crushing season of 6 months every year is maintained for the production of sugar. Beet : While we can guess regarding the original cultivation of sugarcane sugarcane the situation is 2. Sugar Beet: different with reference to sugar beet. The juice of the beet contains a sugar identical with that of  the cane at this discovery was put into practical use. Steps Ste ps in sugar manufacture The sugar is synthesized by the growing plant and the processing in the factory is only a succession of  separations whereby the sugar is separated from the constituents of the plant. Separation of the juice from the fiber by pressure Clarification is a removal of impurities that interfere with subsequent evaporation and crystallization Removal of water by evaporation Conversion of the sugar from the dissolved condition to a solid crystal form Separation of the crystal sugar from the mother liquor followed by molasses obtained from centrifuge. 6. Drying and packing of sugar 1. 2. 3. 4. 5.

Clarification The juice extract from the cane are strained to r emove dirt particles, particles, fiber or pulp after this juice is r eady for clarification. The purpose of clarification is to free the juice as far as possible from all constituents except sugar without altering the sugar itself. Lime is one for the first chemical to be used are universal basis for this clarification since it is both effective and economical for the cost. The main purpose of lime is to neutralize the acidity of juice and converts many of the organic acids into insoluble calcium salt. Thus clarification remains an essential and integral part of the manufacture of sugar. The flow process of liming is given below;

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Analysis of typical cane molasses

Co m p o s i t i o n

P e r c e n t ag e ( % )

Water

20

Sucrose

30

Raffinase

0

Invert Sugar

32

Ash

6

Organic non-sugars

12

Evaporation The juices juices from the clarific clarificatio ation n must must now be evaporat evaporated ed in order order to produc produce e cryst crystal al suga sugar. r. Toda Today y evapo evaporat ration ion is conduc onducted ted by stea steamm-in in evapo evaporat rators ors.. In the first first stag stage e of evapo evaporat ration ion the juice juice is concentrated to 50%-60% sugar. This is made in MEE (Multiple Effect Evaporator) which are very effective and by efficient use of steam. Crystallization At this stage the evaporation is continued to the point where sugar crystals formed and separate from remaining water and impurities. There are various types of crystallizers namely horizontal, cylindrical or U shaped kerns equipped with stirring paddles. After stirring the mixture are cooled to take advantage of the lower solubility of sugar at lowest temperature. Refining The The raw cane cane suga sugarr is subj subjec ected ted to furthe furtherr refinin refining g opera operatio tion n befo before re it is ready ready for for cons consum umpt ption ion.. Adsorption of impurities is followed by crystallization. The refining process takes place in the following sequence. 1. 2. 3. 4. 22/04/09

Affination Melting Defecation Purification with Bone-char or active carbon www.sdsenthil.com

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5. 6. 7. 8.

Filtration Crystallization Centrifuging Finishing

In affination process the raw sugar is mixed with syrup which softens and dissolves the molasses without eroding the sugar crystals. In the defecation process sufficient lime is added to make the solution alkaline and the alkalinity is neutralized with calcium phosphate or phosphoric acid. The precipitate of calcium phosphate or phosphoric adsorbs most of impuritie s.

Bone-char Treatment Co m p o s i t i o n

P er centag e ( % )

Carbon

10

Tri calcium phosphate

83

Calcium carbonate

4

Iron, Nitrogen, Silica, Calcium Sulfide

Traces

The purpose this treatment is primarily to remove color, organic and inorganic substances from the raw sugar solution. Active carbon is used for refining of sugar. It is generally employed from producing a refined, granulated sugar.

By-products Molasses: This is basic basically ally used for cattle cattle feed. Although Although it has the limitatio limitation n of providing providing only carbohydrate carbohydrate high protein yeast can be made from molass molasses es and i norganic nitrogen salts, can can serve as a basis for the protein content in the cattle feed. The recent development is industrial alcohol produced from molasses molasses can be used as motor fuel. Such Su ch a development can simplify the world production of molasses. Bagasse: The quantity is 28,000,000 Tonnes of Bagasse per year. It is right now used in sugar factories factories as fuel developing developing co-generation co-generation plant for producing producing power, manufacture manufacture of plastics, plastics, paper pulp and wall boards. Conversion of sugar to other products Sugar represents practically a chemically pure product available at low cost and it is natural to find that serious study has given rights to development of processes to convert sugar into other products. The various conversions for molasses can be applied for sugar but extensive development can takes place parallel to the potential molasses, bagasse and press-mud whose original name is “Filter Cake”. Some undertakings compile the manufacture of sugar with the production of ethyl alcohol, butyl alcohol, acetone by fermentation. Press-mud (Filt Press-mud (Filter er ca cake) ke):: Pres Press-mu s-mud d or Filter Filter cake cake is the solid olid subs substa tanc nce e obta obtaine ined d afte afterr juice juice clarification. It is almost brown color and it was used as manure for the sugar cane field itself. A sugar factory crushing 2500 TPD of sugarcane generates 75 Tonnes of Filter cake. There are about 500 sugar mills generating sugar in India with crushing capacity ranging from 2500 - 5000 TPD. The recent research on the exploitation of press-mud or filter cake shows the presence of sugar, proteins, fiber, wax and other mineral salts. Sugar is present a 0.5% in press-mud. The Protein content is 3%. The Fiber is 35%. The Wax is 12%. And the remaining is moisture or water. These components can be extracted and used for the increased use of sugar industry. The fiber part of the waste is dried and converted to carbon called as  “Adsorbent Carbon” as they can substitute the role of active carbon in the adsorption operations though in the potential of press-mud it is estimated that we can have 750 crores of rupees provided to national exchequer exchequer annually. These These constituents constituents of downstream downstream of multi component component sugar industry by-product. by-product. They can be applied for fluoride removal to eliminate skeletal flurosis and in the Drugs & Pharma Industry for the production of anti cancer drugs, already in commercial operation in a country like Japan. 22/04/09

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www.sdsenthil.com Last updated: Apr 22, 2009 11:37 AM

T OP OP I C 4 : P H A R M A CE CE U TI TI CA CA L , P O L Y M ER ER S, S, I N D US UST RI R I A L GA SE SE S, P A I N T S A N D PIGMENTS

Drugs A subst ubstanc ance e used used for for treat treatme ment nt / preve preventio ntion n of dise diseas ase e in human human bodi bodies es and anima animals ls.. Typi Typic cal intermediates are converted into final drugs by adding ingredients formulate chemical reactions. Classification S.No.

1

Ca t e g o r y

Use

Analgesics

E x am p l e

Releases mild pain

Aspirin, Acetaminophen

2

Non-Narcotic Analgesics

Releases sever e pain

Morphine

3

Antacids

Neutralize and r emove acid from gastric content

Sodium Bi Carbonate Magnesium Carbonate Aluminum Hydroxide

4

Anti Allergic Agents

Alleviate allergic responses

5

Anti Anxiety Agents

Relief of tension

6

Anti Bacterial Agents

Cur e of Bacterial infection

Sulphadiazine

7

Antibiotics

Chemical substances produced by some species ies of micro icro organis organisms ms that suppres suppress s the growth of harmful species

Penicillin Streptomycin

Therapy of Epilepsies

Phenobarbital,

8

Anti Convulsions

mild

anxiety

Chromolyn Sodium and

Diazepam

Phenytrin 9

Anti Depressants

10

Anti Histamines

11

Anti Hyper Agents

12

Anti Inflammatory Agents

Tension

Over co c ome me mental ti t iredness, depression and fatigue

Doxepin

Reduce intensity reactions

Tripeleamine

of

allergic

Depron

Trea reatment ent of bloo lood pres ressure ure

Reserp erpine ine

Treatment of ar thritis

Ibuprufen Phenyl Butazone

13

Cardiovascular Drugs

Treatment of heart problems

Digitoxin Nitro Glycerin

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14

Central Ne N ervous Sy System Stimulants

Dealing Dealing with central central nervous nervous system system and improve improve resistant resistant against cholera

Amphetamine ine Sulf ulfate Methyl Phenoate

15

Cold Pr eparations

To cure symptoms of cold

Phenyl Propanolamine

16

Cough Pr eparations

Reduce cough

Codiene

/

Dextro Metamorphan 17

Diuretic Agents

Treatment to kidneys for urine problems

Hydro Chloro Thiozole

18

Laxatives

Relieves constipation

Sodium Sulfate Methyl Cellulose

19

Seductive & Hypnotics

Produce to cure depressions in the central nervous system

Phenobarbital

20

Major Tranquillizers

Tr eatment disorders

Chlorpromazine

of

major

mental

Prothilen

21

Chemotherapy Agents

Tr eatment of Cancer

Cyclophospheamide Methatraxate

22

Vaccines and Immunizing Agents

Immu Immunit nity y again against st and Oral infections infections

23

Vitamins

Essential for natur al metap metapholic holic function functions s but not synthesize the body

Bact Ba cteria eriall

/

Typhoid Typhoid vaccine vaccines s and small small pox vaccines Vitam Vitamin in C (ob (obtaine tained d Ascorbic Acid)

from from

Vitamin B Complex (obtained from Thiamine) Vitamin Vitamin B12 (obtaine (obtained d from Cyanacid Butamine)

24

25

Anesthetics

Synthetic Hormone

Make unconcieve insensitive Growth of the body

or

Ether Ethyl Chloride, etc Adrenaline Cortisone

Aspirin (Acetyl Salicylic Acid) – Carboxylation & Acetylation

Us e :

Analgesic - Removes mild pain

Raw Materials Materials Phenol and caustic soda are mixed ito reactor followed by a precipitations tank in which sulfuric acid is 22/04/09

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added to obtain salicylic acid. This is further centrifuged in basket centrifuge followed by a rail operation before the treatment of acetic anhydride in a reactor. The products are filtered, crystallized, centrifuged again and rotary dried to obtain the Aspirin which is Acetyl Salicylic Acid. Vitamin-C

Polymers Introduction: Introduction : substanc substances es consisting consisting of molecules molecules of high molecular molecular weight in the magnitude magnitude of 10 1 03 to 10 7 quantitatively. They consist of basic units called monomers linked together by strong chemical bonds. Plastics, resins, rubber and fibers are examples, where natural polymers like silk, wool, cellulose, starch and natural proteins exists with same melting point made-up of molecules are identical molecular weight. They They are the applied applied for manufa manufact cture ure of electric electrical al and electronic electronic compo components nents,, adhes adhesives ives,, aircraft aircraft component component replacement of metals, coatings, packaged material materials, s, medical equipments, pipes and tubings. Polymers are classified as follows; 1. Based Based on Functionality No. of reactive bonds or groups available coupling at the beginning are during the course of reaction. 1. Uni-functional (one) 2. Bi-functional (two) 3. Tri-functional Tri-functional (three)

2. Based Based o n physical Structure 1. Linear Polymer 2. Cross lined Polymer 3. Branched Chain Polymer

3. Based on Physical P roperties 1. Thermoplastic:

It softens upon heating, regains original hardness upon cooling and they are linear or branched molecules soluble in specific solvents. Eg. Vinyl Poly Ethylene, Polypropylene, etc. 2. Thermosetting: These are insoluble and infusible materials even after heating, cross linked or heavily cross linked substances, insoluble in solvents, highly heat resistant. Eg. Phenol formaldehyde and Silicones 3. Elastomers: These are resistant solids with high flexible strength. Eg. Butadiene derivatives, Poly Isoprene, Iso Butylene derivatives and Polyurethane. 4. Fibers: These are thread forming solids with high tensile strength. Eg. Polyesters, Polyamides, Poly Vinyl derivatives.

Types of Polymerization Reactions 1. P oly Condensation Reaction Monomer react slowly step by step fashion. Small molecules like water, ammonia, sodium chloride are split in the reaction. The intermediate like dimer, trimer exists as stable molecule.

2. Additio n Reaction It is a fast reaction and no by-products are eliminated. The intermediates are radical or ions which are 22/04/09

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short lived and unstable. i. Homo Polymerization R--- R---> RR---R----> RRR------ > Rn ii. Co Polymerization Random Type : RSRRSSRSRSSR Alternate Type: RSRSR iii. Block Polymerization Polymerization RRRSSSSRRR iv. Graft Polymerization SSSSS (Graft) RRRRR (Main chain) SSSSS (Graft) Reaction Mechanism The polymerization reaction consists of 4 steps; i. Initiation nC ----energy---> C* (free radical) ii. Propagation C* + H ---> M* + C M* + H ---> MM* MM* + H ---> MMM* + Mn* iii. Chain Transfer Mn* + M ---> Mn + M* iv. Termination 2Mn* ----> M2n Methods of P olymerization olymerization 1. Homogeneous Polymerization a. Bulk Po lymerization : The monomer is the only feed. It may be a gas or liquid or solid. The polymer is soluble in monomer. Examples; For gas phase - polyethylene and poly propylene. For liquid phase – Polystyrene. Heat dissipation problem occurs because of the viscosity of the polymer s mentioned above. b. Solution P olymerization olymerization:: A monomer monomer dissolves dissolves in a solvent and reaction reaction occurs in solution. solution. Only low molecular weight chain termination takes places more.

2. Heterogeneous P olymerization a. Emulsion Polymerization: Polymerization : Monome Monomerr is emulsif emulsified ied in aqueous aqueous media media using using emulsif emulsified ied agents. Reactions are fast and shrinkage does not form latex or polymer dispersion step takes place. This advantage is lot of impurities is observed from the emulsifying agent which is composite. b. Suspension Polymerization: Polymerization : Monomer, an aqueous media are large droplets in suspension (0.5 – 3 mm size) using agitation agitation apart from the emulsifying agents. agents. Here also polymer polymer insoluble in monomer and irregular surface with internal porosity are obtained in the process.

Polyethylene (Low Pressure Ziegler Ziegler Process) nCH2 ---> (CH2-CH2)n The catalyst employed in this process is titanium tetra chloride (TiCl 4). The catalyst prepared and ethylene molecules are treated in reactor with sulfur impurities after the monomers are completed reactions at a temperature of 79 O C. The product sent to a flash drum evaporator from where the diluents are passed on to a dryer and subsequently fractionated to separate the light ends and heavy ends. After the slurry is washed in water takes to a filter press from which wet polymer is sent to a dryer. From the dryer the substance substance is passed passed into a polymer process processing ing unit from where polyethylene is obtained. obtained. Some times the extrusion process carried out to obtain the pellets of the polymer. This polyethylene obtained by this process is used in package industry, containers, cable insulati ons, pipes, toys and for packaging packaging materials. 22/04/09

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The other polymers polymers are polypropylene polypropylene used in the manufacture manufacture of automobile automobile parts, medical medical equipments, equipments, electronic components, fibers and coatings. PVC is also manufactured for the above purpose and reinforced are specifically manufactured from PVC. Polystyrene is a polymer obtained from bulk polymerization. ABS is a polymer obtained from Acrylo Nitrile, Butadiene and Styrene. They are used in refrigeration lines, vacuum cleaners and automobile components. Epoxy resins are used for chemical resistant materials. Phenol formaldehyde resins are obtained for the manufacture of vanishes and adhesives. Polyesters are obtained from polyethylene terypthalate and used for textile texti le fabrics, hose, bottles, coatings and aircraft components.

Ind ustrial Gases Gases Hydrogen P rocess of manufacture manufacture 1. From H ydrocarbo n and Steam Steam (Steam (Steam Reforming P rocess) CH3CH2CH3 + 3H2O ----> 3CO + 7H2 3CO + 3H2O ----> 3CO2 + 3H2 CH3CH2CH3 + 6H2O ----> 3CO2 + 10H2 Commercial propane obtained from natural gasoline plants are refineries contains sulfur which is removed before processing. The propane in the form of vapor passed through a heater at a temperature of 370 OC. The hot gases passed over a bauxite or metallic oxide catalyst which converts sulfur to H2S. After cooling the gases are scrubbed with aqueous sodium hydroxide and water to remove soluble sulfides. Now the sulfur free propone vapours are mixed with steam and passed on top of a reforming furnace, the propane is converted to hydrogen, CO and CO 2. 2. From Hydr ocarbons by P artial Oxidation Oxidation CnH2n-2 + O2 -----> xCO2 + (n-x) CO + (n-1-y) H 2 + H2O Fuel Oil

CO + H2O ----> CO2 + H2

The CO reacts with water vapor in a shift convertor to form hydrogen as mentioned in the second reaction. 3. From W ater Gas and Steam Steam C (amorphous) + H 2O ----> CO + H2 (water gas) CO + H2O ---> CO2 + H2 Hydrogen produced along with CO2 by catalytically reacting with water gas (40% CO + 50% H 2) with steam at elevated temperature. The CO 2 is removed by scrubbing the gas and relatively pure hydrogen remains which is the desired product. Water gas also forms flue gas obtained by steam or coke or coal at a temperature temperature of 1000 OC or even higher. The exit gas contained 64% H 2, 31% CO 2, 4% N2 and Methane, 1% CO which are cooled in water tower and passed to purification unit. The method of purification depends on the use of hydrogen gas. Suppose this has to be used in the high pressure liquid chromatographic units the purity is highest. This process is obsolete as technology has observed alternate process of hydrogen. 4. Steam-Iro Steam-Iro n Pr ocess This produces Hydrogen by the reaction of steam at high temperature are reduced iron oxide to produce hydrogen with a reduced gas such as water gas in a cyclic operation. The flow sheet is given as;

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5. Thermal Decompositio n of Hydrocarbon Hydrogen is obtained as by product in the manufacture of carbon black by the thermal decomposition of  natural gas. A brick chamber chamber is i s heated to 1300 OC and natural gas is passed through, from this hydrogen 85% is obtained and the carbon black is separated. This process makes a cheapest way to manufacture Hydrogen of good purity and simple technology. 6. From Methanol and steam Hydrogen of higher than 98% purity is manufactured by reaction of methanol with steam at 260

O

C.

CH3OH + H2O -----> CO2 + 3H2 The ease and simplicity simplicity of fabricating this plant, handling raw materials materials and purified hydrogen makes the proces process s more more pract practica icall for produc producing ing hydrogen hydrogen.. The cost cost of methano methanoll preclude precludes s the technolo technology gy that produces on a large scale by the th e process. Uses of H 2 Ammonia plants, methanol plants, Refineries and other organic chemical industries find uses Hydrogen on a large scale. It is one of the lightest substances and is useful for hydrogenation of oils; liquid hydrogen is used as a rocket fuel and in the recent year on a large scale in the electronic industry. Carbon Di-Oxide (CO 2 ) 1. From Steam Steam and N atural Gas 60% of CO2 is a by-product of the production of Ammonia which is obtained by the reaction of N 2 and H2. The reaction is; CH 4 + 2H2O ----> 4H2 + CO2 Burning of fuel in a kiln produces CO 2 by C + O2 ----> CO2 Similarly burning of limestone CaCO 3 --Heat --> CaO + CO2 2. From Fermentation The fermentatio fermentation n of grains grains to produc produce e Ethyl Alcohol Alcohol also also produc produces es a good good quantity quantity of CO2. It is represented by the reaction, C6H12O6 --Yeast--> 2C2H5OH + 2CO2 3. From Sodium Carbonat Carbonate e & Phosphoric Acid In the plants plants manufa manufact cturing uring sodium sodium phospha phosphate te by the reaction reaction of phosp phosphoric horic acid with sodium sodium phosphate pure CO2 is available as a by-product. Na 2CO3 + H3PO4 -----> Na2HPO4 + CO2 + H2O Flow Diagram for manufacture of CO CO 2 by Absorption

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Process 1. Coke is burnt in boiler furnace. 2. Combustion is controlled by grafts so as to flue gas contain 18% CO 2. 3. Steam generated is used for a pumps and compressors followed by heat for the lye boiler section. O 4. The hot (232 C) flue gas containing O 2, CO, N2, Dust, Sulfur, Organic Compounds in the addition of  CO2 are passed through a heat exchanger and economizer. This reduces the temperature to 120 OC. 5. The dilute CO2 pumps from the absorption towers where a counter current aqueous solution of  6. 7. 8. 9. 10.

11. 12.

sodium carbonate develops weak lye. After the absorption of CO2, the strong lye a solution of bicarbonate is pumped through the heat exchangers and slurry is heated. The absorbers operating at 30 OC remove CO2 from flue gas which is released to the atmosphere. The bicarbonate solution is decomposed decomposed to weak lye, i.e. sodium carbonate. The liberated gas consisting of 99.8% CO 2 passes through the water coolers and collectors in gas holders. In the ternary cycle the CO 2 is cooled to 4 O C at a pressure of 75 lbs/in 2 after the first stage of  compressor. The compressors are run by steam from the boiler and the exhaust steam is used in the lye boiler. Long condensing gas is pumped and the 99.9% liquid CO2 is free from impurities and passed onto flash coolers followed by storage in cylinder. In two step by step flash coolers refrigerated by expanding CO2. The temperature is lowered to -7 OC and then to -40 solid CO2.

O

C. The liquid CO 2 is fed to a metering tank and then by the press it is connected to

Uses o f CO2 Refrigeration, Refrigeration, carbonated beverages, beverages, chemicals, chemicals, inerting pressure pressure r equirements and the property property of it’s a colorless, odorless, non combustible combustible gas and some extent volatile volati le when it is exi sts as a colorless liquid.

Acetylene From Calcium Calcium Carbide Calcium carbide is formed when lime (essentially free of phosphates and magnesium carbonate) and coke (low ash content) is mixed in the ratio of 60:40 are heated to a temperature of 2100 OC in a electric furnace. The flow diagram is as follows;

There are two processes available namely the wet and dry processes. In the wet process, large quantity of  water is added releasing acetylene gas while calcium hydrate is discharged in the form of slurry with about 90% water. On the contrary little water is added to calcium carbide in the generator of the dry process.

WULFF P rocess rocess From paraffin hydro carbon by pyrolysis Eg.

C4H10 --steam--> CH CH + CO + H2 C2H4 ------ > CH CH + H2 2CH4 -----> CH CH + 3H2

The yield in the third reaction is only 25%. Acetylene is produced from a wide variety of hydro carbon (natural gas, LPG, naphtha, naphtha, fuel oil, crude oil) by high temperature temperature cracking reactions. reactions. The h eat supplied supplied cracks the hydro carbon to acetylene. The yield in some cases even 95% and high. 22/04/09

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Paints and P igment igments s (surface coating industry)

Liquid P aint aints s It is a dispersion of solid and liquid. Solid consist of pigments. Liquid consists of a resin or a binder of oils also a volatile solvent. An ideal pigment should be opaque, chemically inert, non-toxic, must be wet by the film forming constituents and finally a low cost. The important parameter is called PVC (Pigment Volume Concentration) whose significance is, PVC = (Volume of Pigment in Paint) / (Volume of Pigment in Paint + Volume Volume of Constituent Constituents s in Paint). Paint). The constitue constituents nts are also also called called as vehicles vehicles.. It is expres expressed sed as a percentage.

Manufacturing Manufacturing P rocedure The The vario various us optio options ns neede needed d to mix mix paint paints s is phys physic ical. al. Chemi Chemic cal conve convers rsion ions s are involv involved ed in the manufacture of constituents as well as drying of the film.

Pigments They are colored organic and inorganic insoluble substances used widely in surface coatings, but they are also employed employed in i n ink, plastics, plastics, rubber, r ubber, ceramics ceramics,, paper and lin oleum industry to produce produce different colors. colors. Pigments are classified into; 1. White pigments 2. Black pigments 3. Blue pigments 4. Red pigments 5. Yellow pigments 6. Green pigments

Eg. Titanium Oxide Eg. Carbon Black Eg. Ultramarine Ultramari ne Blue Eg. Ferric Ferr ic Oxide Eg. Zinc Yellow Eg. Chrome Green

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TOPI C 5: DY ES AND IN TERMEDIATES, FERTILI ZE ZERS RS AND F OOD INDUSTRY

Dyes A dye is a color substance which imports color to other material. The process of formation of dye is given as follows;

The unit proce process sses es include include nitration, nitration, sulphona sulphonation, tion, aminat amination, ion, halogena halogenation, tion, hydrolys hydrolysis, is, alkylatio alkylation, n, condensation and addition reaction.

Apart from these there are water soluble dyes like pigments partially dispersed in aqueous medium and import color to the th e substance.

Classification Classification o f Dyes

a. Dyes based on chemical compo sition There are 26 types of dyes by chemical classification. Eg. Nitro Dyes, Azo Dyes and Nitrous Ni trous Dyes, etc.

b. Dyes Dyes based on appli cation There are 12 different types of which six are very important. 1. Acid Dye:

2. 3. 4.

5.

6.

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A water soluble, anionic dyes. Eg. Nylon, Wool & Silk. For Azo dyes . . . . . . . . . . . anthroquin one. The acid acid contains the radicals of of nitro, carboxylic, sulphonic acid acid radicals. There are stable in acid solution. Lower the pH higher the reaction activity. Basic Dye: A water soluble, cationic dye. Eg. Paper, Nylon, Polyester. They yield colored cat ion in solution. Triarylmethane, Cyanine is examples of the dyed compound. ------ Dye: A water soluble dye taken directly by fiber from an aqueous solution containing electrolyte. Cotton, leather, rayon falls in this group and applied for natural dye producing agent. Disperse Dye: A water soluble non ionic dye for hydrophobic fibers from aqueous dispersion to high temperature and pressure. Nylon, Cellulose, polyester is formed by this process dispersion and an absorbed to the fibers. fiber s. Ethanol amine group namely ----------NHCH2CH2OH helps the dispersion category. Reactive Dye: They form covalent bond between dye and fiber. Cellulose fibers and a particular type of Nylon-6 fall in the category. Even chemical reaction form Azo dyes in this category to some extent. Vat Dye: they are water insoluble complex chemical structure namely cellulose fiber especially indigo dye is manufactured from raw material like anthroquinone. The name vatking is defined as solublizing solublizi ng dyes in an aqueous solutions of caustic soda and sodium sodium hydro sulfate. Some times they are colorless and water soluble that taken readily ………. The fibers in the textile industry. Subsequent oxidation oxidation by a pro… insoluble colored form compound. compound. These colorless mixture drives the color by contact with atmosphere.

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Chrome Blue Black

Process sequence involves a batch reactors fitted with mixing facility followed by filtration. The chrome blue black crystals are then passed into the dryers followed by pumping the colored dye compound is separated from the mixture by an external settling mechanism. The application of dye i s transform from bulk consumable ----- to the fi ber stage by four stages. They are, 1. Fiber Preparation Preparation 2. Dyes Bath Preparation 3. Dye Application 4. Completion Mechanism for the particular dye separation and to the consume textile industry where

the particular dye is necessary.

Fertilizer Industry Three major components are necessary in fertilizers as given by Shreve; 1. Nitrogen: Required during early stages of plant growth to promote development of stem & leaves. 2. Phosphorous: This stimulates early growth and accelerates seeding or fruit formation in the later

stages of growth. 3. Potassium: Essential to the development of starch in potatoes and grains, the sugar in fruit and vegetables and the fibrous material of plants, an ample supply of potassium in the soil some times prevent diseases and reduce the effect of excess nitrogen. Thes These e mater material ials s are cons consta tantl ntly y adde added d to the soil. soil. The The variou various s fertil fertilizer izers s are Ammo Ammonium nium Sulfat Sulfate, e, Ammonium Ammonium Nitrate, Nitrate, Calcium Calcium Ammonium Ammonium Nitrate, Nitrate, Urea, Urea, Ammonium Ammonium Chloride, Chloride, Super Super Pho Phosp sphate hate,, Triple Triple Super Phosphate, Ph osphate, Nitro Phosphate, Ammonium Phosphate, etc.

Urea (NH2 CO NH2) or (NH2)2CO The molecular molecular weight is 60 , the melting point is 133 OC, the specific specific gravity is 1.335 and fairly soluble in water. It’s a granular coa coated ted with non-hygrosc non-hygroscopic opic dust similar to phosphate phosphate rock. The end users are fertilizers, animal feeds, industrial plastics, adhesives and coatings. P roductio n of Urea by Ammonium Carbamate Decomposi tion

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Ammonia Ammonia and CO2 are comp compres ress sed for for react reaction ion at 150 atm. atm. and 180 OC in an auto autoc clave lave to form form Ammonium Ammonium Carbam Carbamate ate (NH4COONH2). Urea Urea is form formed ed by dehy dehyd drati ration on in a low low pressu ressure re strip tripping ping operat operation. ion. Proces Process s modif modifica ication tion occurs occurs in recycle recycle of un-reac un-reacted ted ammo ammonia nia and CO2 with with the exces excess s percentage of ammonia in the reaction. The following are the chemical reactions; Main Reactions 1. CO2 + 2NH3 -----> NH4COONH2 2. NH4COONH2 ----- > NH2CONH2 + H2O

Undesirable Side Reactions 1. 2NH2CONH2 -----> NH2CONHCONH2.H2O

Urea

BIURET

The principle raw materials and utilities for the manufacture of Urea are Ammonia, CO 2, Power, Cooling Water and Steam. Process NH3 & CO2 are compressed separately and added to the high pressure autoclave which must be water cooled due to highly exothermic nature of the reaction. The average residence time in the autoclave which is a continuous process is about 2 hours. A mixture of Urea, Ammonium Carbamate, Water, Unreacted Ammonia and CO2 are formed. At this stage the liquid is recued to 27 atms. and fed to a flash evaporator followed by condenser to obtain the solution of Unreacted Ammonia, CO2 and Water. This recycled and an aqueous solution of Urea is passed to the flash drum where further decomposition takes place. The off  gases from this step can be recycled for making the fertilizer. The 80% Urea solution can be sent to vacuum evaporator to obtain molten urea containing less than 1% water. This molten mass is sprayed into a prilling tower where granules are solidified. solidified. At this stage stage BIURET formation has to be avoided avoided and then the resultant Urea is packed and sold. Advantages of Urea It replaces highly acidic ammonium salts in places where soil is already highly acidic and lime is scarce. The granules are obtained easily and the polymer called urea formaldehyde is used in the manufacture of plastics. pl astics. It is used as a cattle feed to the extent of 90% of total requirement.

Food Industry What is a food? – It is a mixture of chemicals consumed by human to satisfy their appetite for nourishment and pleasure. It is classified into food additives, acidulates, anti caking agent, anti foaming agents, anti oxidants, oxidants, bulking agents, agents, colo colorants, rants, emulsifiers, enzymes, fat replacers, replacers, firming agents, flavors, flour bleaching bleaching agents, agents, formulations, formulations, fumigants, fumigants, gases, gases, leavening agents, agents, lubricants, lubricants, nutrients, preservatives, preservatives, processing processing aids, solvents, thickeners thickener s and stabilizers. Food processing processing involves preparations, preparations, assemb assembling ling and preservations. preservations. The normal unit operations operations are applied applied in the food industry. The various techniques techniques employed employed are milling to make the flour, refining (eg. sugar) sugar),, conce concentrat ntration ion (eg. (eg. beverag beverages) es),, reverse reverse osmo osmosis sis for purifica purification, tion, drying drying to remove remove moist moisture, ure, freezing to sustain the life, canning and stabilization to protect food, pasteurization (eg. milk).

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