WDAAA116767_j_16 Cleaning and Flushing of External Piping

Installation Manual

INSTRUCTIONS

16 Cleaning and flushing of external piping

Document ID

WDAAA116767j

Date of issue

16.10.2012

Status

Approved

Classification

Confidential

Installation Manual

Table of Contents 16. Cleaning and flushing of external piping................................................................................................ 16-1 16.1. Cleaning procedure............................................................................................................................. 16-1 16.1.1. Steel pipes.................................................................................................................................... 16-1 16.1.2. Stainless steel pipes..................................................................................................................... 16-2 16.2. Pickling of steel pipes.......................................................................................................................... 16-2 16.2.1. Preparation for pickling................................................................................................................. 16-2 16.2.2. Various types of pickling methods................................................................................................ 16-3 16.2.3. Pickling bath.................................................................................................................................. 16-3 16.2.4. Pickling procedures...................................................................................................................... 16-3 16.2.4.1. Citric acid method.................................................................................................................. 16-4 16.2.4.2. Hydrochloric acid method...................................................................................................... 16-5 16.2.4.3. Phosphoric acid method........................................................................................................ 16-6 16.2.5. Neutralizing/rinsing of piping after pickling................................................................................... 16-6 16.3. Pickling of stainless steel pipes........................................................................................................... 16-7 16.3.1. Stainless is not always stainless................................................................................................... 16-7 16.3.2. Chemical surface treatment.......................................................................................................... 16-8 16.3.3. Mechanical surface treatment....................................................................................................... 16-8 16.4. Sandblasting........................................................................................................................................ 16-8 16.5. Flushing of pipes................................................................................................................................. 16-8 16.5.1. Preparation for flushing................................................................................................................. 16-9 16.5.2. Flushing system setup.................................................................................................................. 16-9 16.5.3. Specifying the flushing equipment.............................................................................................. 16-11 16.5.4. Flushing temperature.................................................................................................................. 16-12 16.5.5. Flushing procedure..................................................................................................................... 16-13 16.5.6. After flushing............................................................................................................................... 16-14 16.6. Flushing of external LO piping systems............................................................................................. 16-14 16.6.1. Pipe module final flushing check, W38 & W46 engine................................................................ 16-14 16.6.2. Pipe module final flushing check, W32 engine........................................................................... 16-17 16.6.3. Lube oil filling and emptying pipes.............................................................................................. 16-17 16.7. Flushing of external LFO unloading system...................................................................................... 16-17 16.7.1. Flushing unloading piping with diesel oil.................................................................................... 16-17 16.7.2. Flushing of piping from storage tank to feeder unit and return.................................................. 16-19 16.7.3. Flushing of piping from LFO tank to pipe racks and return........................................................ 16-20 16.7.4. Flushing of fuel piping inside the power house........................................................................... 16-21 16.7.5. Final flushing check of the LFO system...................................................................................... 16-23 16.7.5.1. Part 1 (and 3)........................................................................................................................ 16-24 16.7.5.2. Part 2 (and 4)........................................................................................................................ 16-25 16.8. Flushing of external HFO piping system............................................................................................ 16-27 16.8.1. Hand cleaning of piping between buffer tank, day tank and separator unit............................... 16-27 16.8.2. Flushing of piping between the buffer tank and the separator unit............................................ 16-27 16.8.3. Cleaning of the pipeline from the HFO separator to the HFO day tank...................................... 16-28 16.8.4. Diesel oil flushing of piping from HFO day tank to HFO feeder and return................................ 16-29 16.8.5. Flushing of HFO piping from the day tank up to the pipe racks and return from the pipe racks 16-30 16.8.6. Flushing of the HFO pipeline in the pipe rack and booster connection(s) inside the power house 16-31 16.8.6.1. Flushing the HFO pipes in the pipe rack (step 1)................................................................. 16-32 16.8.6.2. Flushing the booster connections (step 2)........................................................................... 16-33 16.9. Cleaning and flushing of gas systems of SG and DF engines........................................................... 16-33 16.9.1. Cleaning TIG welded carbon steel piping................................................................................... 16-33 16.9.2. Cleaning TIG welded stainless steel piping................................................................................ 16-34 16.9.3. Storing and cleaning of stainless steel pipes.............................................................................. 16-34 16.10. Flushing of compressed air systems............................................................................................... 16-35 16.11. Flushing of cooling water system.................................................................................................... 16-36 16.11.1. Flushing the expansion pipes................................................................................................... 16-36

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16.11.2. Flushing the pipes between pipe module and radiators........................................................... 16.11.3. Flushing the whole cooling radiator system.............................................................................. 16.11.4. Flushing the pipes between pipe module and cooling tower................................................... 16.11.5. Flushing the whole cooling tower system................................................................................. 16.12. Cleaning of steam boilers, steam drums, feed water tanks and related water spaces................... 16.12.1. Alkaline boiling-out.................................................................................................................... 16.12.2. Acid boiling-out......................................................................................................................... 16.12.3. Neutralization boil-out............................................................................................................... 16.12.4. Passivation................................................................................................................................ 16.12.5. Inspection, flushing and precautions........................................................................................ 16.12.6. Boil-out of an oil-fired boiler..................................................................................................... 16.13. Cleaning of steam pipes and feed water pipes............................................................................... 16.13.1. Cleaning the pipes between auxiliary boiler, steam header and exhaust gas boilers.............. 16.13.2. Cleaning the steam pipes between header, pipe rack, consumers inside the power house and blow-down tank............................................................................................................................... 16.13.3. Cleaning the steam pipes between header, consumers outside the power house and blowdown tank...............................................................................................................................................

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16. Cleaning and flushing of external piping

16.

Cleaning and flushing of external piping

16.1

Cleaning procedure

16.1.1

Steel pipes Properly clean all pipelines between the engine and its auxiliary units, tanks, heat recovery units, etc. prior to the startup of the plant. Cleanliness is an utmost prerequisite for the trouble-free operation of the power plant. The various cleaning procedures for pipelines in different systems are shown in Table 16-1. All pipes (dimensions) are according to EN 10220.

Table 16-1 Various cleaning methods System

Pipelines

Fuel oil

B

C

D

Pipes acc. to EN 10305-4, EN 10216-2

X

X

X [1]

Lube oil

Pipes acc. to EN 10305-4, EN 10216-2

X

X

X

X

Nozzle temp. control

Pipes acc. to EN 10305-4, EN 10216-2

X

X

X

X

Compressed air

Pipes acc. to EN 10305-4, EN 10216-2

X

X

X

Cooling water

Pipes acc. to EN 10305-4, EN 10216-2

X

X

X

District heating

Pipes acc. to EN 10305-4, EN 10216-2

X

X

X

Steam

Pipes acc. to EN 10217-1

X

X

X

Natural gas

Pipes acc. to EN 10305-4, EN 10216-2

X

X

Exhaust gas

All pipes

X

X

Charge air

All pipes

X

X

Sludge

Pipes acc. to EN 10216-2

X

X

[1]

A

X

E

F

G

H

X

X

X

X

For details, see WDAAA180387.

A = Washing with alkaline solution in hot water at 80 °C for degreasing (to be done only if pipes are greased) B = Removing of slag, rust and scaling with tools (steel brush, hammer, etc.) and grinding welding seams inside the pipe C = Blowing with compressed air D = Pickling (refer to section 16.2) E = Sandblasting or shot blasting (refer to section 16.4) F = Flushing with lube oil (refer to section 16.5) G = Flushing with LFO (refer to section 16.5) H = Flushing with water D and E are alternative cleaning methods, but only use sandblasting or shot blasting if it is possible to visually check the cleaning result.

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16.1.2

Installation Manual

Stainless steel pipes Storing Place stainless steel pipes in a dry and ventilated location, if they are to be stored for a long period. If the pipes are greased, use a non-chlorinated solvent to remove the grease. This must be done to avoid leaving residue of chlorine ions. The chlorine ions can initiate crevice, pitting and stress corrosion.

Cleaning Do not clean stainless steel pipes with any type of metallic wire brush other than stainless steel. Avoid grinding or polishing with grinding wheels or belt sanders, as they tend to overheat the surface to the point where corrosion resistance cannot be restored even with pickling. If a very heavily contaminated stainless steel surface is to be cleaned by sandblasting, ensure that the sand is truly clean (not recycled). Another method is glass ball blasting. Do not use blasting methods that could roughen the surface. Do not use steel shot blasting.

16.2

Pickling of steel pipes Pickling removes rust, slag, weld spatter, etc. from the pipes. Before starting pickling of a pipeline construction, mechanically remove all weld spatter, coarse slag, etc. (if accessible), as described in Table 16-1. Check the cleaning results visually. After completing the pickling, no further welding is allowed. However, if additional welding of a pickled pipe is required, pickle the pipe again.

16.2.1

Preparation for pickling Before the pickling work starts, the following procedures have to be agreed between Wärtsilä and the pickling Contractor: ● The chemicals used for pickling have to be approved by Wärtsilä. ● The mixing properties have to be agreed and a pre-test must be done. ● The method to be used has to be explained and agreed. ● The equipment to be used has to be verified (pumps, heaters, pools, sealings, bolts and nuts, etc.). ● The environmental protection has to be agreed (neutralization and discharge). ● Personnel safety equipment has to be reviewed and accepted. ● The pickling method must be verified (see section 16.2.2). ● Passivation and protection must be done before re-installation. ● Final tightening and re-installation (sealings, bolts and nuts, tightening torque, etc.) must be planned. ● The way of working has to be discussed in detail, in order to get a general understanding on why, how and for how long time the flushing shall be done. ● Design documents like flow diagrams, lists, etc. have to be identified. The following documents shall be established at the site: ● Flushing order and time schedule ● Logbook defining the status and progress of work (signed by the Contractor and the Wärtsilä representative)

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● Inspection report ○ The report has to be approved by Wärtsilä. The report will be part of the commissioning report later on. ● Organisation and responsibilities ○ The Contractor and Wärtsilä representative shall each name a person who will have the authority to sign the reports for each system. The authorized persons shall have the knowledge to decide on what to look for and to decide when the systems are acceptably clean.

16.2.2

Various types of pickling methods The following methods can be used for pickling: 1 Sending the pipes to a shipyard or factory for pickling. 2 Pickling at site pipe by pipe: Disassemble all pipes and fill them one by one with chemicals according to the pickling procedure. Put blind flanges in one end of the pipes and lift up the other end of the pipes on some kind of support.

NOTE The pickling should be done outside the powerhouse, since a lot of toxic fumes are coming from the solutions (affecting both humans and equipment). 3 Pickling at site: Pickling baths of adequate size, into which the pipes are put for pickling, are manufactured at site. 4 Pickling at site using a pump for filling the pipes: ● Alternative 1: Take the pipes outside of the building and connect them together into a loop. ● Alternative 2: Do the pickling inside the building, system by system.

NOTE Remove all air from the pipes in order to ensure a good pickling result.

For methods 2–4, the following equipment is needed: ● Pools for the chemicals and for hot water ● Heaters for heating of water and for the neutralization solutions ● Compressed air for blowing of the pipes ● Oil for protecting the inside of the pipes (after a Wärtsilä supervisor has accepted the pickling result).

16.2.3

Pickling bath Pickling baths should be made of PVC, polyethylene, wood or stainless steel, class AISI 316. The size of the baths must be large enough to fully cover the pipes sunk into the baths for treatment with pickling chemicals. Heaters for the hot water pool and the neutralizing pool should be installed.

16.2.4

Pickling procedures Three different pickling methods are presented: Citric acid, Hydrochloric acid and Phosphoric acid.

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Wärtsilä recommends the use of Citric acid as the first choice in site conditions.

16.2.4.1

Citric acid method Prerequisites

NOTE Wash greased pipes with a hot alkaline solution before starting the pickling procedure.

NOTE Remove any paint from inside pipes or pipe components.

Complete all steps from 1 to 5 without any interruptions. Long breaks between the steps might affect the pickling result. Procedure 1

Pickle the pipes with an acid solution. Fill the pipes or immerse them in an acid solution of 6–8% citric acid (C6H8O7). Add a bit of alcohol (methylated spirits) to break down the surface tension, and a squirt or two of detergent to help with any degreasing. ● The key is to adjust the concentration to the task – light concentration for lightly rusted items, heavy concentration for encrusted items. ● Remember to put the powder into the water, not the other way around. ● Using heated (the hotter the better) water (60–80 °C) speeds the process. ● The acid is working when you notice bubbles rising. De-rusting can take 2-4 hours depending on the condition of the pipe and the concentration/temperature of the solution. It is possible to cut a test piece of the same pipe material and put it in a plastic bucket that contains the same citric acid solution. By monitoring the test piece, it is possible to determine the proper processing time. When pickling at site and using a pump to circulate the solution, the pump pressure and flow depend on the pipe system to which the pump is connected. The main idea is that the pickled pipes are full of solution and the solution circulates. Product information: ● Name: Citric acid monohydrate, E330 ● Importer: Algol Chemicals Oy ● Foreign producer: Jungbunzlauer B.V.

NOTE Remember that you are working with an acid. Citric acid is irritating to eyes and may cause skin irritation. Always use proper protection (rubber gloves and boots, protective glasses). If the ventilation is poor, or if working for long times close to the acid, a mask should be used to prevent inhalation of toxic fumes.

16-4

2

Blow the lines with compressed air to remove all pickling solution.

3

Rinse the pickled pipe properly with a sufficient amount of hot water and blow with dry compressed air immediately after the rinse.

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16. Cleaning and flushing of external piping

Check the result. ● A Wärtsilä supervisor must check the result. If the result is not good, repeat the pickling procedure. After the pickling result is approved by Wärtsilä, fill the pipes with protection oil.

5

Plug the pipes when they are dry at the inside surface. Postrequisites

NOTE To avoid corrosion of the pipes, start the flushing immediately after the pickling procedure. Make sure that the water is clean. The use of dirty water might affect the pickling result. Disposal considerations: ● Crystal or flour can be disposed of as a solid waste or burned in a suitable installation subject to the Environmental Protection (Duty of Care) Regulations 1991. ● Small amounts of citric acid solution can be flushed down a sink with a large quantity of water (the pH value must be between 6 and 11), unless local rules prohibit this. ● For large amount, discuss with the local sewerage station how to handle the solution.

16.2.4.2

Hydrochloric acid method Prerequisites

NOTE Wash greased pipes with a hot alkaline solution before starting the pickling procedure. Complete all steps from 1 to 8 without any interruptions. Long breaks between the steps might affect the pickling result. Procedure 1

Pickle the pipes with an acid solution. Fill the pipes or immerse them in an acid solution of 10% hydrochloric acid (HCl) and 10% formalin inhibitor (HCHO) for 4–5 hours. Examples of brands: ● Armohib 28 ● Rhodine 213 ● Metacorr AC1100.

CAUTION Remember that you are working with an acid. Always use proper protection (rubber gloves and boots, protective glasses). If the ventilation is poor, or if working for long times close to the acid, a mask should be used to prevent inhalation of toxic fumes. 2

Blow the lines with compressed air to remove all pickling solution.

3

Rinse the pipes with hot water at 70 °C.

4

Perform the neutralization.

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Fill the pipes or immerse them in a neutralizing solution of 10% caustic soda (NaOH) and 50 g Na3PO4 (sodiumtriphosphate) per litre. The temperature of the neutralizing solution should be 40–50 °C. Keep the pipes in the solution for 20 minutes.

CAUTION Remember that you are working with an alkaline. Always use proper protection (rubber gloves and boots, protection glasses). If the ventilation is poor or if you are working long times close to the solution, wear a mask to prevent inhalation of toxic fumes. 5

Blow the lines with compressed air.

6

Rinse with hot water at 70 °C.

7

Check the pickling result. ● A Wärtsilä supervisor must check the result. If the result is not good, repeat the pickling procedure. After the pickling result is approved by Wärtsilä, fill the pipes with protective oil.

8

Put protection covers on the pipe ends. Postrequisites

NOTE To avoid corrosion of the pipes, start the flushing immediately after the pickling procedure. Make sure that the hot water is clean. The use of dirty water might affect the pickling result.

16.2.4.3

Phosphoric acid method When using the phosphoric acid method, the pipes are immersed in a pickling bath. Do not use this method on site. Pickle the pipes in 15–72% phosphoric acid for a time of 20 minutes to four hours. The recommended pickling temperature is 45 °C. Check the concentration of the pickling solution regularly and add acid if the check shows a low concentration. This chemical is suitable to use for steel, aluminium and zinc. Generally, the supplier's recommendation has to be followed. Example of brand: ● Antox Supra.

16.2.5

Neutralizing/rinsing of piping after pickling Rinse the pickled pipe properly with a sufficient amount of hot water and corrosion inhibitor at 60 °C, and blow with dry compressed air immediately after the rinse. Steam can also be used to rinse the pipes from pickling solution. It is important to remove the pickling solution completely from the pipe in all bends and possible pockets inside the pipe. Plug the pipes when they are dry on the inside surface. If the pipes are stored for a long time (days) in a corrosive environment without protection, corrosion will take place and the pickling has to be repeated.

WARNING Always remember that you are working with an acid. Make sure that your skin is covered and you are using protective glasses.

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Pickling of stainless steel pipes Use these instructions for guidance and information only. Always obtain valid instructions from the supplier of the pickling chemicals for each specific project.

16.3.1

Stainless is not always stainless The concept of "stainless" or "rust-free" steel must be qualified. Common stainless steel will not usually rust when exposed to normal atmospheric conditions; but in other surroundings, e.g. in acids or in water containing chlorides, the risk for corrosion increases. The fact that stainless does not rust in many situations does not mean that the metal itself is noble. The corrosion resistance is due to the steel surface reacting to oxygen, which results in the formation of a thin protective layer that prevents corrosion. The oxide layer, consisting mainly of chromium oxide, is called a passive layer, and the process of building the layer is called passivation. Corrosion of the stainless steel may occur when this thin, protective oxide layer is damaged, disturbed, or depleted in chromium. Chromium depletion often happens during exposure to high temperatures, for example during welding.

The need for postweld treatment of stainless steel welds A protective oxide layer can be rebuilt if both the weld heat tint and the underlying chromium depleted layer are removed in the proper manner. The corrosion resistance of the stainless steel will then be restored. There are two ways to do this: ● Chemical surface treatment ● Mechanical surface treatment. Chemical treatment means that the damaged oxide layer is dissolved, usually with acid solutions. There are two main methods: pickling and electrolytic polishing. Mechanical treatment means that the surface layer is removed by grinding, abrasive blasting or brushing.

Pickling is the superior method Research has been carried out to evaluate which method produces the best corrosion resistance. The comparisons show that pickling is the best method for achieving optimum corrosion resistance.

Requirements for successful pickling The pickling agent needs to adhere well to the surface. Different pickling products are available on the market: pickling paste, pickling gel, and pickling solution. Pickling paste is often preferred because it adheres best to the stainless surface, and neither runs nor falls off. Additionally, paste is more worker friendly, in that the splash danger is minimized. The agent should remove all heat tint, the underlying chromium depleted layer, as well as residual slag. The pickling agent should, under normal conditions (15–22 °C), give a clean surface after about an hour. The following accessories are necessary when pickling: ● A suitable acid burn ointment for treating small areas of the skin that may have come in contact with pickling acid. ● A "neutralising agent" for treating the resulting wash water after pickling. The wash water is acidic, and contains heavy metals dissolved from the stainless steel. ● An indicator, which facilitates spray-pickling through its colour and at the same time reduces the formation of hazardous nitric fumes.

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Installation Manual

Chemical surface treatment When pickling, the metal oxides are dissolved by the combination of hydrofluoric and nitric acids. These acids dissolve the heat tint and the underlying chromium depleted zone. The clean surface is then re-passivated rapidly by the oxygen in the air, and thus the welded object achieves an optimal (for the alloy) corrosion resistance. This method is technically superior for the surface treatment of stainless steel since it removes, through chemical action, any areas of inferior corrosion resistance on the surface. The disadvantage is that pickling acids are corrosive and poisonous, and must be handled with care. Electrolytic polishing is an electrochemical pickling method which requires costly equipment. It requires that the object be immersed in a bath, which can be difficult for large fabrications. Portable units do exist, but they are generally limited to the cleaning of relatively smooth surfaces (80–400 grit).

16.3.3

Mechanical surface treatment Grinding can be done with a rotating abrasive disc, or with coarse abrasive coated papers. If this method is correctly done, it gives good results. Heat tint and weld spatter are efficiently removed. However, the resultant rough grinding marks (more than 120 grit roughness) are areas where localized corrosion may start, especially pitting, crevice corrosion, and stress corrosion cracking. This means that a further treatment after grinding should be done, e.g. a mechanical polishing followed by a chemical cleaning or passivation. Shot blasting or peening is the process where glass beads, or abrasive particles such as corundum or olivine sand of varying size are sprayed with high pressure against the surface. It needs to be done at a sufficiently oblique angle to prevent blasting particles into the surface. Done properly, blasting is a quick and effective way of removing heat tint, but not always the underlying chromium depleted layer. Depending on the abrasive particle size, it may leave a too rough surface. High demands are also made on the cleanliness of the blast media, especially for iron contamination. Brushing with a stainless steel wire brush can be used when surface quality requirements are lower, e.g. on the outside of pipes and equipment.

16.4

Sandblasting Sandblasting is used in the cleaning of pipelines when pickling is not enough, but it is not an alternative for pickling. When sandblasting, ensure that no harmful particles are left inside the pipelines. Also remember the limitation of sandblasting: use it only if it is possible to visually check the cleaning result.

16.5

Flushing of pipes The purpose of the flushing is to remove all debris and foreign material, which could cause damage to the engine or to auxiliary equipment, from the pipelines.

NOTE The flushing tank, heater, pump, filters, pipes and hoses are not included in the Wärtsilä supply.

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16. Cleaning and flushing of external piping

Preparation for flushing Before the flushing work starts, the following procedures have to be agreed between Wärtsilä and the flushing (pickling) subcontractor: ● The flushing media has to be decided (LFO, lube oil, water, depending on the line to be cleaned). ● The method to be used has to be explained and agreed (mesh sizes, check points and checking intervals). ● The equipment to be used has to be verified (pumps, heaters, pools, sealings, bolts and nuts, etc.). ● The working areas and environmental protection must be agreed (neutralization and discharge of the flushing media). ● Personnel safety equipment has to be reviewed and accepted. ● The pipe routing and looping must be identified and agreed. ● Passivation and protection must be done before re-installation. ● Final tightening and re-installation (sealings, bolts and nuts, tightening torque, etc.) must be planned. ● The way of working has to be discussed in detail, in order to get a general understanding on why, how and for how long time the flushing shall be done. ● Design documents like flow diagrams, lists, etc. have to be identified. The following documents shall be established at site: ● Flushing order and time schedule ● Logbook defining the status and progress of the work (signed by the Contractor and Wärtsilä representative) ● Inspection report ○ The report has to be approved by Wärtsilä. The report will be part of the commissioning report later on. ● Organisation and responsibilities. ○ The Contractor and Wärtsilä representative shall each name a person who will have the authority to sign the reports for each system. The authorized persons shall have the knowledge to decide on what to look for and to decide when the systems are acceptably clean.

16.5.2

Flushing system setup To perform the flushing at the site, build a movable flushing system. The flushing system set up is shown in Fig 16-1.

NOTE Drain the flushing tank regularly to remove condensed water from the tank. Install flushing filters horizontally to the return line just before the flushing oil tank. See Fig 16-2.

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Fig 16-1

Installation Manual

Flushing unit for external piping

GUID-E6EB7112-6643-46CA-9F42-923CD8C0798D v1

Table 16-2 Flushing system equipment

16-10

Item No

Pieces

1

1

Flushing oil tank (normal steel or stainless steel)

2

1

Heater with temperature controller (electric or steam)

3

1

Ventilation filter

4

1

Manhole

5

1

Temperature indicator

6

1

Closing valve

7

1

Strainer (safety filter for flushing pump)

8

1

Pump with electric motor (screw pump or impeller pump)

9

8

Closing valve

10

2

Flexible rubber hoses (industrial type for pipe connections)

11

2

Pressure indicator

12

2

Flushing filter (see Fig 16-2)

Part

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Fig 16-2

16.5.3

16. Cleaning and flushing of external piping

Flushing filter

GUID-5079C561-9AE0-45EE-ABB6-AA1BB0ECC52F v1

Specifying the flushing equipment When choosing the flushing pump, tank, heater capacity and filter size, determine the following values for the different systems: ● Flow rate in each system ● Operating temperature of the liquids ● Liquid volume in the system plus the tank and piping. The flushing pump capacity is directly related to the flushing time and also to the flushing result. The heater capacity has to be calculated (the flushing temperature must be at least be the same as the temperature during normal operation). The capacity of the flushing pump should be dimensioned so that the Reynolds number (Re) exceeds 25000. For the inner pipe diameter, the largest pipe size in the system shall be used. A higher oil temperature decreases the viscosity and consequently increases the Reynolds number. The cleaning efficiency increases with the Reynolds number. A Reynolds number of 25000 is considered the lower limit for efficient cleaning.

Where: ∂ = Viscosity [cSt] d = Pipe inside diameter [mm] Q = Flow [l/min] Re = Reynolds number Example: Flushing oil Shell Tellus TX 32 ∂ = 10 cSt at 80 °C d = 150 mm Q = 1770 l/min

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or

Table 16-3 Minimum flow capacity for different pipe diameters

Fig 16-3

16.5.4

DN

Flow (l/min) for Shell Tellus at 80 °C, Re = 25000

25

336

32

442

40

508

50

643

65

829

80

973

100

1263

125

1545

150

1879

200

2445

Flushing flow rate for different pipe size

GUID-F0F44DB0-3D76-4938-A506-4F54939B7793 v1

Flushing temperature The temperature of the flushing oil is very important to achieve optimal flushing results. The flushing temperature must be at least the same as the temperature during normal operation. The relationship between the Reynolds number and the oil temperature and viscosity is shown in Fig 16-4 and Fig 16-5. The diagrams are based on the flow rate in Table 16-3.

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Fig 16-4

Reynolds number variation depending on temperature (Shell Tellus TX 32)

GUID-78F1B807-956A-4914-B59C-23AF7FF847AD v1

Fig 16-5

Reynolds number variation depending on viscosity GUID-36C42928-06C1-448A-8D7D-1510F1AE7BD6

16.5.5

v1

Flushing procedure During the flushing, inspect the filters regularly and clean them when necessary, according to the flushing procedure. Use the following flushing filters: ● 30 mesh ≈ 0.5 mm ● 60 mesh ≈ 0.25 mm ● 100 mesh ≈ 0.15 mm.

NOTE For more detailed information concerning screens and mesh, refer to chapter 1.

Start the flushing with the 30 mesh, continue with the 60 mesh and finally use the 100 mesh. If the pipes are very clean, the 100 mesh can be used directly. The systems that should be flushed with these meshes are: ● lubricating oil piping ● LFO piping ● HFO piping ● nozzle heating piping.

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Perform the flushing systematically according to the flow diagrams. Complete the flushing for one engine at a time and only one step at a time. First flush the lubricating oil system, then the LFO system and finally the HFO system.

16.5.6

After flushing Procedure 1

Drain the entire system of flushing oil.

2

Dismount some pipes and check visually that the pipes are clean. Place a piece of paper or cloth on the floor. Hold the pipes vertically by hand above the paper sheet, give a couple of blows with a hammer on the pipe and check that no debris comes out. If debris is found on the paper, clean the whole pipe system again. Also check any hidden spaces inside the piping by means of a swivelled mirror.

3

If the piping system includes valves, such as thermostatic valves, disconnect and drain them one by one to ensure that no flushing oil is left in them.

4

Plug all pipelines and ensure that no dirt can enter the system. Remove the plugs at the last moment before the remounting of the pipework.

5

If the engine oil sump was used as flushing tank, drain the sump and clean it properly from flushing oil. Sweep the sump bottom with a magnetic pick-up to verify an acceptable result.

6

As soon as the sump has been cleaned from all flushing oil, shut the crankcase covers and seal them. If possible, fill up the sump right after completing the flushing.

CAUTION Reuse of flushing oil as engine or system oil is forbidden!

16.6

Flushing of external LO piping systems Since the arrangement to flush a large system requires planning and material procurement locally, be prepared to reserve time well enough in advance to comply with the erection schedule. Note that a flushing unit is not available even by request from the product factories nor network offices. In general, the required hoses and accessories must be purchased locally and a team must be assigned to carry out the flushing.

16.6.1

Pipe module final flushing check, W38 & W46 engine See the flow diagram WDAAA167409. Perform the final flushing check after the pipe and cooler module assembly has been completed.

NOTE The flushing of the pipe module must be supervised.

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Procedure 1

Fabricate all needed equipment: flushing tank, hose connections and flushing filters. Carry out a pickling cleaning on all steel equipment. See drawing WDAAA167687.

2

Install the flushing tank slightly higher than the pre-lubrication pump, to avoid harmful cavitation. If an electrical heater is used for heating the flushing oil, install it in the flushing tank.

3

Open the pipe module lube oil connections number 201, 204 and 205, located on the engine side. If a lube oil separator is used for heating the flushing oil, open number 213 and 214 as well. Visually inspect the inside of the piping and clean it if it is dirty.

4

Install all hoses, couplings and flushing filters. See drawing WDAAA180309. Carefully tighten the connections and make sure that there are no loose parts or any dirt inside the pipes or hoses. Cover the flushing tank with a tarpaulin.

5

Visually inspect the pipe and cooler module. Check that all flange connections are tight and that they have gaskets.

6

Follow the pipe/cooler module lube oil pipe flow diagram and do the following: ● Check the position of the non-return valve and open the closing valve after the prelubrication pump. ● Open the inlet and outlet valves of the lube oil cooler. ● Close the inlet and outlet valves of the automatic filter. ● Open the automatic filter bypass valve. ● Open the lube oil safety filter top covers (two). ● Take out the filters from the safety filter; cover and store them in a dry place. Do the same with the filter tightening nuts. ● Inspect visually the cleanness of the inside of the safety filter; check the condition of the cover’s O-ring gasket and reinstall the covers on the filter. ● Close the drain valves at the bottom of the lube oil safety filter and if the piping has several drain valves, close them all. ● In order to fill the system with flushing oil, turn the change-over valve’s position from the safety filter to both filters. ● Close the drain valve from the hose coupling number 201. ● Open the valve from the hose coupling number 204. ● If a lube oil separator is used for heating the flushing oil, check the hoses, pipes and the position of the valves leading from the separator. Close the valve.

7

Install the flushing mesh to the filters on top of the flushing tank. Start with mesh 60.

8

Fill the flushing tank with clean oil (fill through a fine filter). Check that there are no leaks.

9

Start heating the oil. Stop the heating when the temperature of the oil reaches 60 °C.

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NOTE Check the cable connection of the heater. Continuously check the oil temperature. When using the LO separator for oil circulation, monitor the flushing oil pressure and temperature. When the flushing oil pressure has increased by 2 bar from the starting pressure, stop the flushing and clean the mesh. 10 Fill the pump and the motor bearings with grease according to the service manual. Check the direction of rotation for the pre-lube oil pump. Turn the pump pressure adjusting screw a few rounds anticlockwise in order to decrease the pressure. Check the level in flushing oil tank. 11 Start filling the system. Run the pump for a few seconds only and top up the tank when required until the system is filled up. Open the venting valves at the LO cooler and the safety filter during the filling. Close the valves when oil starts to come out. Turn the safety filter change-over valve to the one-filter position. 12 When the flushing oil tank is full and oil is circulating from the flushing tank to the pipe module and returning back to the tank via the flushing filter, adjust the oil pressure to 1 bar. Record the starting pressure and use it as reference pressure for deciding when the mesh has to be cleaned. 13 During the flushing, observe the following important things: ● Open or close the valve from connection 204 every 3 or 4 hours. ● Check the temperatures of the casing and bearings. ● Check that pump does not cavitate. ● Check the oil level in the tank and the temperature of the oil. Check that there are no leaks. ● Check the filters every 4 hours. ● Change to mesh 100 when, after 4 hours of flushing, no more dirt is trapped in mesh 60. (Note: minimum flushing time is 4 hours.) ● When no more particles are trapped in mesh 100 after 4 hours running, stop the oil heating and circulation. ● Let the oil temperature drop to 40 °C and start the flushing again. The job is ready when after 4 hours of flushing no particles can be found in the mesh 100. ● Change the valve position of the safety filter to “change-over valve”.

NOTE The flushing result has to be inspected and approved by personnel authorized by Wärtsilä. 14 Disassemble the flushing arrangement. a Disconnect the power supply. b Empty the flushing tank to clean barrels. Use the mobile LO transfer pump. c Connect the mobile pump to the hose coupling 2/201 drain valve and empty the piping system.

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Start the pre-lubricating oil pump a few seconds also in order to empty the suction side. When the system is drained, disconnect the power supply to the pre-lubricating pump. Open the venting valves of the LO cooler and the safety filter. d If the LO separator was used for heating, drain the hoses, piping and separator. Disconnect the hoses and couplings. Do not let oil drip on the floor. Inspect the piping. Drain the remaining oil from the pipes with the mobile pump. Cover connections 213 and 214 with temporary plastic caps. Check the cleanness of the separator inlet strainer. e Drain thoroughly and disconnect all flushing devices. Inspect the piping. 15 Install the filter cartridges in the safety filter. a Open the top covers. b Pump out the oil from the chambers. c Open the drain valves, and inspect and clean the filter chambers. d Take new filters from the store (inspect cleanness before installation). e Check the cleanness of covers and the condition of O-rings. f

Install the covers to the filters.

g Close the drain and venting valves. 16 Start the bellow assembly from the middle of the pipe module/engine. See the installation instructions. Check that all draining and venting valves are closed. The pipe module is now ready for the start of the commissioning.

Pipe module final flushing check, W32 engine

16.6.2

See final flushing for W32 module, document number WDAAA182786. For external systems, see this instruction.

16.6.3

Lube oil filling and emptying pipes See the flow diagram, document number WDAAA175712 and WDAAA175775.

16.7

Flushing of external LFO unloading system

16.7.1

Flushing unloading piping with diesel oil See the flow diagram WDAAA168202.

NOTE Never leave the flushing process unsupervised. Do not let the pump run dry. Keep an eye on the pump bearing temperatures. Before flushing, clean all the temporary steel piping materials (used for flushing) with a pickling solution. For flushing with diesel oil, extra pipes and flushing filter are not included in the Wärtsilä scope of supply. Procedure 1

Install the flushing tank slightly higher than the unloading pump unit.

2

Connect the flushing or unloading hose (2) from the flushing tank to the unloading pump unit.

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The hose has to be a reinforced rubber hose of the same diameter as the suction piping, or larger. 3

If the suction piping before the unloading pump unit is long, equip the unit suction strainers (4) with a flushing mesh. Begin with mesh size 30 and end with size 100.

4

Turn the vertical part of the filling pipe leading to the LFO storage tank down towards the ground, in order to make the flushing easier and faster. Connect the flushing hose (2) from the end of the piping (11) to the flushing filter at the top of the flushing tank (1). The hose has to be of the same size as the piping or at least 3" in diameter. If the distance between the LFO storage tank and the unloading pump unit is long, a piece of some other suitable pipeline can be used for the return. Make sure that the pipeline used has been cleaned with pickling solution first.

5

If the unloading system has been equipped with a flow meter, bypass the meter to begin with. Let the flushing pass through the meter only during the last few hours of the process.

6

Double-check all connections and venting devices. Inspect the flushing tank, clean it and fill it with clean flushing oil. Check that there are no leaks.

7

If needed, install a mesh of size 30 inside the flushing filter as well as in the unloading pump unit suction strainer.

8

Grease the pump bearings in accordance with the pump manual before the pumps are started. Check that the inlet and outlet valves are open and that the pump rotates in the correct direction.

9

Start by slowly filling the pipes with flushing oil. Only run the pump for short periods of time. Check the flushing oil level in the flushing tank and check for leaks.

10 Begin by running one pump. Carefully vent the air and make a note of the suction pressure and the pressure after the pumps. Rising pressures indicate that the flushing mesh is dirty and that the pumps must be stopped for cleaning of the mesh. 11 Start the other pump and check the pressures. If the pressures are too high, or the pumps are cavitating, or the flushing diesel oil begins to foam excessively; stop one of the pumps for a while. 12 Begin flushing using a mesh of size 30. When the mesh stays almost clean, continue with mesh size 60, and finally size 100. During the flushing, gently hammer the welding seams. Cover the flushing tank openings during the flushing. To avoid water in the oil, drain the flushing tank regularly. 13 The flushing is ready when after three hours of continuous circulation mesh 100 is free of any sand, metal, dirt or other harmful particles. 14 If the unloading system will be out of use for a longer period of time, fill the system with clean diesel oil. Mix the flushing oil with 25–50% engine oil and circulate it in the piping for a few hours to give protection. 15 When the flushing has been approved, drain the whole system. Use oil barrels or similar for storing the flushing oil.

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NOTE Do not let the oil leak onto the ground.

16 Open a flange connection and inspect the cleaning. 17 Reassemble the unloading system, close draining and venting devices and cover the suction hose inlet.

16.7.2

Flushing of piping from storage tank to feeder unit and return See the flow diagram WDAAA168212.

NOTE Before flushing, clean all the temporary steel piping materials (used for flushing) with a pickling solution. Never leave the flushing process unsupervised. Do not allow the pump to run dry. Keep an eye on the temperatures of pump bearings and electric motors. Procedure 1

If the LFO tank is larger than 150 cubic metres, or the tank is not completely ready, or it has already been filled with clean fuel, use a separate flushing tank (400 l or larger).

2

If a separate flushing tank has to be used, separate the piping from the LFO storage tank by closing the valve and installing a blind flange on the valve for safety reasons.

3

Install the flushing tank slightly higher than the LFO feeder unit and in a suitable place near the LFO storage tank.

4

Connect a hose or steel pipe between the flushing tank (1) and the pipeline leading from the storage tank to the feeder. The hose has to be a reinforced rubber hose of good quality and of the same diameter as the piping, or larger. Mount the hose as straight as possible.

5

Check the piping leading from the storage or flushing tank to the LFO feeder as well as the venting and drain devices and flange connections.

6

Check the condition of the LFO feeder unit and install a flushing mesh of size 30 in the suction strainers (11).

7

Close the feeder outlet valve and, for safety reasons, install a blind plate between the flanges in the outlet of the feeder as well as in the piping between the feeder and the pipe rack/booster.

8

Loosen the tension adjusting screw in the feeder’s pressure control valve or replace the valve with a pipe spool. Cover the valve and store it in a dry place.

9

Check the return piping from the LFO feeder to the LFO storage tank. Also check venting/draining devices and flange connections.

10 Install and connect the flushing filter in a suitable place at the end of the return piping between the storage tank and the pipe flange connection. Alternatively, install the flushing filter in the manhole at the top of the storage tank or the flushing tank and connect it to the return pipe with a hose or pipe of the same diameter as the pipeline. 11 Install a mesh of size 30 inside the flushing filter. 12 Inspect the tank to make sure it is clean and fill the tank with clean flushing oil.

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Use a filter when filling the tank. Check that there are no leaks. 13 Grease the pump bearings in accordance with the pump manual. Open the inlet valve of the feeder unit and check that the pump rotates properly. 14 Slowly start to fill the piping with flushing oil. Only run the pump for short periods of time. Check the oil level in the flushing tank and check for leaks. Carefully vent the air from all pipes. 15 Run the pump and make a note of the suction pressure and the pressure after the pump. Increasing pressure during flushing indicates that the flushing mesh is dirty. Stop the pumps and clean the mesh. 16 If the unit has two feeder pumps for LFO, start the second pump as well. Check the pressures. If the pressures are not too high and the pumps are not cavitating, use both pumps for flushing. If the oil starts to foam excessively, stop one of the pumps for a while. 17 Begin flushing using mesh size 30. When the mesh is clean, change to mesh 60 and finally to mesh 100. Gently hammer the welding seams during the flushing. To avoid water in the oil, drain the flushing tank at regular intervals. Cover the flushing tank openings during the flushing. 18 The flushing is complete, when after three hours of continuous circulation using mesh 100), the mesh is free of any sand, metal, dirt or other harmful particles. 19 Before ending the flushing, check the pressure regulating valve adjusting screw. If it has loosened, adjust the feeder line pressure back to 4 bar. (This is needed for the following part of the flushing). If the valve was removed, reinstall it and test the working pressure. 20 Drain the piping slightly and open a flange connection in order to check if the pipes are clean. Postrequisites Do not remove the flushing arrangement if some of it is needed later on.

Flushing of piping from LFO tank to pipe racks and return

16.7.3

See the flow diagram WDAAA168365.

NOTE Before flushing, clean all the temporary steel piping materials with a pickling solution. Never leave the flushing process unsupervised. Do not allow the pump to run dry. Keep an eye on the temperatures of pump bearings and electric motors. Procedure 1

Check that the LFO feeder outlet valve is closed. Remove the blind plate or flange and connect the outlet piping to the feeder. Do not let oil leak onto the floor.

2

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Check the piping leading from the feeder up to the pipe racks inside the power house. Check the flange connections, the venting and draining devices and the position of the valves. If the pipeline has an external connection to other LFO consumers, separate the pipe from the main pipeline and install a blind plate or flange at the nearest place.

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Flush the pipe for other LFO consumers together with other smaller piping. 3

Separate the LFO inlet pipe and the return fuel pipe from the pipe racks. Fabricate and install a bypass with a flushing filter. Install a mesh of size 30 inside the filter. All steel parts must be cleaned with pickling solution.

4

Check the return piping from the bypass up to the LFO storage tank. Also check flange connections, and venting and draining devices. If the pipeline has the option of a flow meter, turn the valves to the bypass position. Only let the flushing oil pass through the meter for the last few hours of the process.

5

Lock the return line valve(s) position to the LFO storage tank position..

6

Connect the flushing hose between the pipeline (after the three-way valve) and the flushing filter arrangement. Disconnect the suction pipe from the storage tank as well as the pipeline from the safety valve and install the flushing hoses number 16 and 17.

7

Install a mesh of size 30 inside the flushing filter and a mesh of size 60 inside the suction strainer in the LFO feeder.

8

Check the oil level in the flushing tank, and open the valves in the feeder and the pipe to check for leaks.

9

Start filling the piping with flushing oil. Run the pumps only for short periods of time and vent the pipes at the same time.

10 When the whole system has been filled with oil and the air has been vented, start running the pumps continuously. Make a note of the suction and line pressures. Rising pressures during the flushing indicate that the mesh is dirty. Stop the pumps and clean the filter. 11 During the flushing, perform the following important checks and actions: ● Gently hammer the welding seams with a hammer or a piece of pipe. ● Check that there are no leaks. ● Check the flushing oil level in the tank. ● Check that there is no cavitation noise from the pumps and check the casing temperatures. 12 Begin the flushing process using a mesh 30. When the mesh is clean, change to mesh 60 and finally to mesh 100. The flushing is ready when after 3–4 hours of continuous flushing with mesh 100, the mesh is free of sand, metal, dirt or any other harmful particles. The person responsible for the flushing must approve the piping cleanness before the flushing is terminated. 13 If the pipes will be out of use for a longer period of time, fill them with LFO. During the last hours of the flushing procedure, mix the flushing oil with engine oil to give protection to the pipes. 14 In order for the flushing to be approved, drain the piping and open a few flange connections to inspect the cleanness of the piping. 15 Remove all flushing equipment and install the piping permanently. Remove the flushing mesh from the suction strainers. Close all valves.

16.7.4

Flushing of fuel piping inside the power house See the flow diagram WDAAA169857.

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Example: If the plan is to start with DG1 or DG2 (both using the same booster unit), flush the piping marked with dashed flow lines first and the piping marked with divided flow lines next. Parts of DG3 and DG4 need to be flushed together with the first pipes in order to avoid any extra isolation valves. WDAAA204630.

NOTE Never leave the flushing process unsupervised.

Procedure 1

Finish the pipe installation and check that all pipes have the needed equipment, draining and venting devices.

2

After the piping assembly has been approved, mark all pipes on location and in their correct positions.

3

Disassemble all pipes and transport them to the testing and cleaning area outside the power house.

4

Connect the pipes in a way that is suitable for the flushing. In order to avoid air pockets, install temporary venting plugs. Plan the flushing flow in such a direction that it first passes through the pipes of larger diameter and passes last through the pipes of the smallest diameter in the end of the flushing loop. Do not install any valves or instruments because the pickling solution will damage them.

5

Carry out a pressure test with water and carefully vent the air.

6

Do the pickling by circulating the acid in the piping loop. Use a suitable acid-proof pump and equipment. Vent the air carefully.

7

Open a few flanges after neutralizing and check the result of the cleaning. If the pipes are still rusty, repeat the pickling process.

8

Start the flushing as soon as possible after the pickling. Flushing equipment needed: ● Flushing tank, 400 l or larger ● Heavy-duty suction filter and isolation valves ● Flushing pump with large flow capacity, more than 30 cubic metres/hour – preferably a pump that has a pressure regulating valve ● Reinforced hoses of good quality, 5–10 cm in diameter ● Heavy-duty hose couplings ● Flushing filter with large filter mesh surface and mesh sizes 30, 60 and 100 ● Pressure gauge 0–6 bar ● Clean diesel oil.

9

Assemble the flushing equipment according to drawing WDAAA169857.

10 Double-check all connections, inspect the cleanness of the flushing tank and fill it with clean diesel oil for flushing. Check that there are no leaks. 11 Install a mesh of size 30 inside the flushing filter. 12 Slowly start to fill the piping with flushing oil. Only run the pump for short periods of time. Check the oil level in the tank. 13 After filling the pipes, run the flushing pump and carefully vent the air.

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Make a note of the flushing pressure, because a pressure increase during the flushing can indicate that the mesh is dirty and needs to be cleaned. 14 Begin flushing the pipes with mesh 30. When the mesh is clean, change to mesh 60 and finally to mesh 100. During the flushing, gently hammer the welding seams. Cover the flushing tank during the flushing procedure. 15 The flushing is ready when, after 3–4 hours of continuous circulation with mesh 100, the mesh is free of any sand, metal, dirt or other harmful particles. 16 After the flushing, drain the system. Use oil barrels or similar for storing the flushing oil.

NOTE Do not spill oil on the ground.

17 Open a flange connection and inspect the cleaning. Protect the pipes with engine oil and carefully cover all pipe ends with plastic caps or similar. 18 Move all pipes inside the power house and do the final installation in the correct place. Do the final flushing of the fuel system with all units connected together. A pressure test can also be done for separate pipes. The pickling can be performed in different ways: by filling each pipe with acid separately or by using a pickling bath.

Final flushing check of the LFO system

16.7.5

See the flow diagram WDAAA169870. Procedure 1

After the final tank inspection, fill the LFO storage tank with clean diesel fuel. Use at least enough oil to fill and circulate the LFO system.

2

Check the piping leading from the tank to the LFO feeder as well as the return piping. Fill the piping from the tank to the feeder and carefully vent the air and check for leaks.

3

Keep the feeder outlet valve closed. Start the feeder pump and make a note of the outlet pressure; adjust the pressure, if needed. Check for leaks along the return pipeline to the LFO storage tank.

4

Do the following checks: ● Check the piping from the LFO feeder to the pipe rack modules. Check flanges and venting/draining devices. ● Check the interconnections of the pipe rack modules and all the fuel piping between the engines, the fuel oil units, the boosters and the pipe rack modules. Tighten the bolts of the blind flanges at the end of the pipe rack. ● Check that all fuel oil unit inlet and outlet valves are closed. ● Check that the three-way valve in the booster unit is positioned so that the return fuel from the fuel oil units runs to the LFO storage tank – not to the booster mixing tank. ● If the return piping from the pipe rack modules to the LFO storage tank has a flow meter, open the bypass valve and lock the return line valve(s) in LFO storage tank position.

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5

Start the feeder and slowly open the outlet valve. Fill the pipeline, the pipe rack modules and the piping between the pipe rack modules and the fuel oil units. Vent the air and check for leaks. Now the feeder can be run non-stop.

6

Remove the filter inserts from all fuel oil units and store them in a dry place. Check that the pump suction strainer is clean, but do not remove it.

7

The final check of the pipeline for LFO to other consumers can be done by placing a flushing mesh of size 100 in the last flange connection before the consumer tank. Fill the tank and check the cleanness of the mesh.

8

Fabricate a bypass flushing filter for the fuel oil hose connection before the tank. Clean all steel parts with pickling solution. See drawings WDAAA193579 (W38 & W46), WDAAA215229 (W32) and WDAAA193580.

16.7.5.1

Part 1 (and 3) See the flow diagrams WDAAA169905 and WDAAA171033. Procedure 1

Install the bypass flushing filter in the pipeline of the last DG set. If the time schedule for the commissioning is tight, install the filter to the DG set when the commissioning is planned to start. Inspect the cleanness of the flushing filter and install it between the engine and the pipe module or the fuel oil unit.

2

Install a mesh of size 60 inside the bypass flushing filter.

3

Open the fuel oil unit LFO inlet valve manually. Fill the unit and the flushing filter with fuel and vent the air from the fine fuel filter. Check that there are no leaks.

4

Open the fuel oil unit fuel return valve (HFO) manually. Check that there are no leaks in the return piping from the fuel oil units to the pipe racks, the booster and up to the LFO storage tank. As the fuel oil is circulated by the feeder pump, make a note of the pressure from the flushing filter manometer.

5

Check that the fuel oil feeder pump inlet valve from the fuel oil unit is open. Perform grease filling on the pump bearings and check the pump’s rotation and seal guard devices.

6

Start the fuel oil feeder pump. Make a note of the pressure in the flushing filter and listen for cavitation noise.

7

During the flushing, when the pressure rises above one bar (14.5 psi), the flushing filter valves must be closed and the mesh cleaned.

8

In order to clean the bypass flushing filter mesh, stop the feeder pump in the fuel oil unit and close the valves in the flushing filter.

9

When cleaning the LFO feeder unit suction strainer, stop the fuel oil unit feeder pump as well as the LFO feeder unit pump and close the LFO feeder inlet/outlet valves.

10 When after four hours of continuous circulation with mesh 60 the mesh is almost clean, change to mesh 100. 11 During the flushing, do the following checks: ● Check that there are no leaks. ● Check for cavitation noise (this is very harmful to the pump). ● Check the pump casing temperatures (bearing).

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● Check the fuel level in the LFO tank. ● Check the mesh every six hours (at least). ● Check the pressures in the LFO feeder and flushing filter. 12 When, after four hours of continuous circulation using mesh 100, the mesh is free of sand, metal, dirt or other harmful particles, the flushing is ready. 13 Start part two of the flushing process.

Part 2 (and 4)

16.7.5.2

See the flow diagrams WDAAA169913 and WDAAA171076. See also the following drawings:

WDAAA170675: Final flushing check, Booster unit WDAAA171023: Booster service filter insert WDAAA171079: Flushing filter device between engine and pipe module WDAAA193579: Flushing filter assembly W38 & W46 WDAAA215229: Flushing filter assembly W32 WDAAA193580: Flushing filter frame. Procedure 1

Follow the booster unit flow diagram and start preparing the booster for flushing. a Turn the three-way valve to the LFO position. b Open the service filter and place a flushing mesh of size 100 around the filter insert. Reinstall the insert with the mesh back into the service filter and turn the position of the valve in the service filter. The mesh prevents dirt from entering the insert. c Bypass the flow meter. Only let the flushing oil pass through the meter during the last few hours of the process. d Set the three-way valve on the fuel return pipe from the engine(s) to the booster in the correct position, so that all the return fuel flows to the fuel tank(s) and not to the mixing tank. e Open the booster pump inlet and outlet valves. f

Open the inlet and outlet valves of one of the heaters. Keep the valves of the other heater closed; switch over every few hours.

g Bypass the viscosity meter/sensor. h Close the final booster outlet valve. i

Check that all venting and draining devices are closed.

j

Open all manometer valves.

k Check the booster unit inlet and outlet piping. l

Connect to the main power supply.

2

Start filling the booster unit by slowly opening the valve from the pipe racks. Vent the air and open the mixing tank’s air vent. Wait until the indication light “low level in mixing tank” switches off. Close the venting valve. Check that there are no leaks.

3

Change the flushing filter mesh to size 60.

4

Slowly open the booster outlet valve and check that there are no leaks in the piping to the pipe racks/fuel oil units.

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5

Carry out a first grease filling on the pump bearings and check the booster pump’s rotation.

6

Start one of the booster pumps and keep an eye on the outlet pressure. The pressure should be around 6 bar (when all fuel oil unit valves are closed). If not, correct the pressure by means of the pressure regulating valve from the pipe rack.

7

Manually open the HFO inlet and fuel return valves from the fuel oil unit as well as the valves from the flushing filter. The pressure in the flushing filter should be lower than 6 bar.

8

Start the fuel oil unit feeder pump. Check the pressure in the flushing filter.

9

Check and record the pressures in the LFO feeder, the booster unit and the flushing filter. Increased pressures indicate that the meshes and filters should be cleaned.

10 During the flushing, observe the following important things: ● Cavitation can be reduced by turning the booster three-way valve in position to let part of the return fuel oil from the fuel oil unit run to the booster mixing tank.

NOTE Cavitation is very harmful for the pumps.

● Monitor the pump bearing (casing) temperatures. ● Monitor the pressures – suction and outlet. ● Check for leaks. ● Monitor the fuel level in the LFO tank. ● Monitor the cleanness of the mesh in the flushing filter. Check it every 4 hours. ● During each mesh-cleaning stop, switch booster operating pumps. 11 In order to clean the flushing filter mesh, it is only necessary to stop the fuel oil unit feeder pump and to close the valves from the flushing filter. 12 In order to clean the booster service filter mesh, it is necessary to first stop the fuel oil unit feeder pump and then stop the booster pump. Also close the booster inlet valve from the pipe racks and turn the valve position from service filter to automatic filter. When restarting the pumps, first start the booster pump and then the fuel oil unit feeder pump. 13 If the LFO feeder suction filter needs to be cleaned and the unit does not have a bypass possibility, begin by stopping the fuel oil unit feeder pump. Next, stop the booster pump and finally the LFO feeder pump. Close the feeder inlet/outlet valves. When restarting, start the LFO feeder pump first, the booster pump second and the feeder pump from the fuel oil unit last. 14 When the mesh 60 filter is clean, switch to mesh 100. 15 If the mesh of size 60 in the booster service filter is clean as well, change to size 100. 16 The flushing process is ready when, after four hours of continuous flushing with mesh 100, the mesh in the bypass flushing filter is free of sand, metal, dirt or other harmful particles. The cleanness of the mesh in the booster service filter is not critical. 17 The person responsible for the flushing must approve the result of the flushing. 18 Close all valves. Cut off the power supply to the units.

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19 Remove the flushing equipment and install it to the next DG set for flushing. 20 Reinstall the filter inserts inside the fuel oil unit fine filter casing.

16.8

Flushing of external HFO piping system See the flow diagram WDAAA180387.

16.8.1

Hand cleaning of piping between buffer tank, day tank and separator unit If the piping is of a very large diameter (> DN 100) and it is difficult to get a flushing pump of suitable capacity, or if each pipeline is very short, equip the piping with several flange connections to enable cleaning by hand. Procedure 1

Carefully clean welds and flanges to remove welding slag.

2

Perform a pressure test.

3

Perform the pickling process in a suitable way.

4

Use LFO, rags and – if possible – compressed air to clean the piping pipe by pipe.

5

After the cleaning, protect the piping with lube oil.

6

Inspect each pipe carefully before the final assembly. Also inspect tanks and the unit side of the piping.

Flushing of piping between the buffer tank and the separator unit

16.8.2

See the flow diagram WDAAA172686. Procedure 1

Fabricate and arrange all needed flushing equipment. The flushing pump must have a large pumping capacity. All steel flushing equipment must be cleaned with pickling solution. All flushing hoses must be of a suitable diameter for the pump capacity or of the same diameter as the piping.

2

If the volume of the buffer tank is larger than 150 cubic metres, it is possible to use a separate flushing tank (> 400 l). Flushing when using a large buffer tank requires a large amount of flushing LFO because the tank must be filled up to the height of the outlet pipe. See drawing WDAAA167687.

3

Open the first flange connection after the buffer tank and the outlet pipe and valve. Separate the pipe flanges in order to connect the flushing hoses.

4

Install the flushing hose from the flushing or buffer tank to the flushing filter/pump. Use strong hose clamps of good quality.

5

Install the flushing hose from the flushing filter/pump to the pipeline from the buffer tank to the HFO separator unit. Use strong hose clamps of good quality.

6

Check the pipelines from the HFO buffer tank to the HFO separator unit and return. Also check venting and draining devices.

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7

Separate the piping from the HFO separator connection flanges and install the bypass pipe or hose. If the pipe is long, the bypass can be equipped with a flushing filter to reduce the flushing time. Do not remove the blind plates from the HFO separator connection flanges.

8

Install the flushing filter and hose to the end of the pipeline.

9

Install a mesh of size 30 inside the flushing filter(s) first.

10 Inspect the cleanness of the tank, close the outlet valve and fill the tank with flushing LFO. Use enough oil for the flushing process. 11 Open the tank outlet valve and fill the piping. Check that there are no leaks. 12 Start the flushing pump, vent the air and record the pressure in the flushing filter. A rising pressure will indicate the intervals for cleaning the flushing filter mesh. Check that there are no leaks. 13 During the flushing, perform the following checks and actions: ● Check the LFO level in the flushing tank. Make sure the tank openings are covered. ● Check that there are no leaks. ● Check the flushing meshes every three hours. ● Gently hammer the welding seams with a piece of DN 50 pipe or similar. ● Check the pump temperatures and pay attention to signs of cavitation. ● Check the pressures. 14 When the flushing filter mesh 30 is almost clean, change to mesh 60 and correspondingly, when mesh 60 is almost clean, change to mesh 100. 15 The flushing is ready when after three hours of continuous flushing using mesh 100 the mesh is free of dirt or harmful particles such as sand, metal or welding slag. The person responsible for the flushing and commissioning must approve the cleaning. 16 If the piping will be kept dry for a longer period of time, mix the flushing oil with lube oil and circulate it the last few hours of the flushing process. This will give protection to the pipes. 17 Close the flushing tank outlet valve, drain the piping and inspect the cleaning. Do not let flushing oil leak onto the ground or onto the concrete floor.

Cleaning of the pipeline from the HFO separator to the HFO day tank

16.8.3

See the flow diagram WDAAA172738. Procedure

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1

Change the location of the bypass before the HFO separator, from the HFO inlet pipe to the clean HFO outlet pipe. Inspect the return pipe to the buffer tank, cover or if possible, assemble the HFO separator unit. Remove the blind plate.

2

Check the clean HFO piping from the HFO separator to the HFO day tank.

3

Move the flushing filter with the hose from the HFO return pipe to the clean HFO pipe before the HFO day tank and flushing tank. The HFO return pipe can be connected to the HFO buffer tank.

4

Change mesh 30 to inside of the flushing tank.

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If bypass has equipment with flushing filter the mesh size can remain 100. 5

Continue flushing according to steps 11–17 in section 16.8.2.

6

Drain the piping and the flushing tank. If the buffer tank was used, inspect the cleanness and close the tank.

7

Remove all flushing equipment, inspect the piping and connect all pipes permanently without any blind plates. Close all draining and venting devices.

16.8.4

Diesel oil flushing of piping from HFO day tank to HFO feeder and return See the flow diagram WDAAA173337.

NOTE All temporary steel piping materials used in the flushing procedure must be cleaned with pickling solution. Never leave the flushing process unsupervised. Do not run the pump dry. Keep an eye on the temperatures of pump bearings and electric motors. Procedure 1

Use a separate flushing tank (400 l or larger) if the HFO day tank is larger than 150 cubic metres, if the tank is not completely ready or if it is already filled with clean separated fuel.

2

If a separate flushing tank is needed, separate the piping from the HFO day tank closing valve and install a blind flange on the valve for safety.

3

Install the flushing tank slightly higher up than the HFO feeder unit and in a suitable place near the HFO day tank.

4

Connect a hose or steel pipe from the flushing tank to the pipeline leading from the day tank to the feeder. The hose has to be of the same diameter as the piping or larger. Use a reinforced rubber hose of good quality and mount the hose as straight as possible.

5

Check the piping leading from the day tank or flushing tank to the feeder. Also check venting/draining devices and flange connections.

6

Check the condition of the HFO feeder unit and install a flushing mesh of size 30 inside the suction strainers.

7

Close the feeder outlet valve and for safety reasons, install a blind plate between the flanges in the outlet of the feeder and in the piping from the feeder to the pipe rack/ booster.

8

Loosen the tension adjusting screw in the feeder pressure control valve or alternatively, replace the valve with a pipe spool. Cover and store the valve in a dry place.

9

Check the return piping from the HFO feeder to the HFO day tank. Check venting/ draining devices and flange connections.

10 Install and connect the flushing filter in a suitable place at the end of the return piping between the HFO day tank and the pipe flange connection. Alternatively, install the flushing filter in the manhole at the top of the day tank or flushing tank, and connect it to the return pipe with a hose of the same diameter as the pipeline. 11 Install a mesh of size 30 inside the flushing filter. 12 Inspect the cleanness of the tank and fill it with clean flushing oil.

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Use a filter when filling the tank. Check that there are no leaks. 13 Open the feeder unit inlet valves, carry out a first grease filling on the pump bearings in accordance with the pump manual and check that the pump rotates properly. 14 Slowly start to fill the piping with flushing oil. Start one of the pumps and run it only short periods of time. Check the flushing oil level in the tank. Check that there are no leaks. Carefully vent the air from all pipes. 15 Run the pump and record the suction pressure after the pump. Rising pressures later on will indicate that the flushing mesh is dirty and that the pumps need to be stopped for cleaning of the mesh. 16 If the unit has two feeder pumps for HFO, start the second pump as well. Keep an eye on the pressures. If pressures are not too high and the pumps are not cavitating, use both pumps for flushing. If the flushing oil starts foaming excessively, stop one of the pumps for a while. 17 Begin flushing using mesh 30. When the mesh is almost clean, change to mesh 60 and finally to mesh 100. Gently hammer the welding seams during the flushing. Drain the flushing tank at regular intervals to avoid water in the oil. The flushing tank openings must be covered during the flushing. 18 The flushing is ready when after three hours of continuous circulation using mesh 100, the mesh is free from dirt, sand, metals or other harmful particles. 19 Before terminating the flushing procedure, check if the pressure regulating valve adjusting screw has loosened. If so, the feeder line pressure must be adjusted back to 4 bar (this is required for the following part of the flushing process). If the valve was removed, reinstall it and test the working pressure. 20 Drain the pipes slightly in order to open a few flange connections and inspect the cleanness of the pipes. 21 Close all valves and clean the flushing filters. 22 Do not remove the flushing arrangement since some of it will be needed later on. Cover the flushing tank and piping openings.

Flushing of HFO piping from the day tank up to the pipe racks and return from the pipe racks

16.8.5

See the flow diagram WDAAA190746 and WDAAA190747.

NOTE All temporary steel piping materials must be cleaned with pickling solution. Never leave the flushing process unsupervised. Do not run the pumps dry. Keep an eye on the temperatures of pump bearings and electric motors. Procedure

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1

Check that the HFO feeder outlet valve is closed. Remove the blind plate or flange and connect the outlet piping to the feeder. Do not spill oil on the floor!

2

Check the piping leading from the feeder up to the pipe racks inside the power house. Check the flange connections, the position of the valves and the venting/draining devices.

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3

Separate the HFO inlet and the return fuel pipe from the pipe racks. Fabricate and install a bypass with a flushing filter. Install a mesh of size 30 inside the filter. All steel parts must be cleaned with pickling solution.

4

Check the return piping from the bypass up to the HFO buffer tank. Also check flange connections as well as venting and draining devices. If the pipeline has the option of a flow meter, turn the valves in bypass position and only let the flushing oil pass through the meter the last few hours of the process.

5

Lock the return line valves position to HFO buffer tank position.

6

Change the tank area flushing filter from HFO feeder return to pipe racks return. Connect the HFO feeder return to the flushing tank (HFO day or separate flushing tank). The pressure regulating valve in the HFO feeder will work as a safety valve. The needed hoses must be of at least the same size as the piping.

7

Install a mesh of size 30 inside the flushing filter and a mesh of size 60 inside the suction strainers in the HFO feeder.

8

Check the flushing oil level in the flushing tank and open the valves in the feeder and in the flushing tank. Check that there are no leaks.

9

Start filling the piping with flushing oil. Only run the pump short periods of time. Vent the air from the pipelines. Check the oil level in the flushing tank and check for leaks during the filling.

10 When the whole system has been filled and vented, run the pump continuously. Keep an eye on the pressures. If the pressures are fine and there is no cavitation, start the other feeder pump as well. Record the suction and line pressures. Rising pressures later on will indicate that the filter meshes need to be cleaned. 11 During the flushing, perform the following important checks and actions: ● Gently hammer the welding seams with a piece of pipe or similar. ● Make sure that there are no leaks. ● Check the flushing oil level in the tank. ● Make sure that there is no cavitation noise in the pumps and check the pump casing temperatures. ● Check the flushing mesh every four hours. 12 Begin flushing the pipes using a mesh of size 30. When the mesh is clean, change to mesh 60 and finally to mesh 100. The flushing is ready when, after 3–4 hours of continuous circulation using mesh 100, the mesh is free of sand, metal, dirt or any other harmful particles. The person responsible for the flushing must approve the cleanness of the pipes before the process is terminated. 13 For the approval of the flushing, the piping needs to be drained and a few flange connections must be opened for the inspection. 14 Close the piping, remove the bypass before the pipe racks, inspect the piping and connect the pipes to the pipe racks. 15 Start the last part of the HFO pipe flushing in the pipe racks and the booster(s).

16.8.6

Flushing of the HFO pipeline in the pipe rack and booster connection(s) inside the power house See the flow diagram WDAAA173409.

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Procedure 1

Check the pipe rack's internal piping and the HFO piping leading from the HFO feeder up to the pipe racks.

2

Fabricate and install a bypass with a valve at the end of the pipe racks. The bypass should lead from the end of the HFO pipeline to the return fuel pipe end of the pipe racks. The bypass can be a steel pipe or hose, but make sure that it is not of a smaller diameter than the pipeline. Close the bypass valve.

3

Fabricate and install a bypass for the last booster unit in the pipe rack connection. The bypass is for the “counter connection flanges” between connections A and D. The bypass can be a hose or steel pipe of the same diameter as the piping or larger.

4

Close all HFO inlet valves to the booster in the pipe racks.

5

Turn the booster unit’s inlet three-way “change-over” valve to the LFO position.

6

Turn the booster’s return three-way valve in such a position that the return fuel from the engines flows to the mixing tank.

7

To reduce the flushing time, fabricate and install a flushing filter in the return fuel pipeline in a suitable place near the pipe racks – if possible, with valves.

8

Install or change the mesh in: ● the tank area, the flushing filter for the return to the flushing tank; mesh 100 ● the HFO feeder suction strainers; mesh 100 ● the pipe rack flushing filter for return fuel; start with mesh 60.

16.8.6.1

Flushing the HFO pipes in the pipe rack (step 1) See the flow diagrams WDAAA190756 and WDAAA190757.

NOTE All temporary steel equipment used in the flushing procedure must be cleaned with pickling solution. Never leave the flushing process unsupervised. Never run the pumps dry. Keep an eye on the pump and electric motor bearing temperatures. Make sure that there is no cavitation noise. Check the flushing oil level in the flushing tank. Procedure 1

Start the HFO feeder pump, check the pressures and check that there are no leaks in the pipe rack or in the bypass.

2

Open the bypass valve in the end of the pipe rack. When the flushing oil is circulating, start the second pump as well and check the pressures.

3

Record the HFO feeder suction and outlet pressures. Rising pressures will indicate the intervals for cleaning the mesh.

4

When the return line flushing filter mesh 60 near the pipe rack is clean, change the mesh inside the filter to size 100. When after 3–4 hours of continuous circulation mesh 100 is free of dirt, sand, metal or other harmful particles, the flushing is ready. Postrequisites When step 1 of the flushing procedure has been completed, proceed with step 2 (flushing of the booster connections).

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16. Cleaning and flushing of external piping

Flushing the booster connections (step 2) Prerequisites Before starting the flushing of the booster connections, step 1 of the flushing procedure (flushing of the HFO pipes in the pipe rack) must be completed and the actions recorded. See the flow diagram WDAAA190764 and WDAAA190765. The flushing should be performed starting from the last booster unit. Procedure 1

Close the flushing bypass valve at the end of the pipe rack.

2

Start the HFO feeder pump and check the pressures.

3

Slowly open the booster HFO inlet valve in the pipe rack and check that there are no leaks.

4

Start the second HFO feeder pump as well. Check and record the pressures.

5

When after 3–4 hours of continuous circulation the return line flushing filter mesh 100 is clean, if the plant has more than one booster unit, move the flushing equipment to the next booster unit and start the same process.

6

The flushing is ready when all booster units have been flushed.

7

If the HFO pipelines will be empty of fuel for a longer period of time, mix the flushing oil with lube oil and circulate it for a few hours before removing the equipment. This will protect the pipes.

8

Drain the piping and the units, remove all flushing equipment, and assemble all pipes and flanges permanently. Do not spill any oil on the ground or floor!

9

The HFO pipelines are ready for commissioning after the trace heating and insulation assembly.

Cleaning and flushing of gas systems of SG and DF engines

16.9

Gas pipes can be made of carbon steel or stainless steel. Stainless steel pipes require less work; for instance, the pickling containing rinsing is not required, which saves time.

Cleaning TIG welded carbon steel piping

16.9.1

Procedure 1

Remove slag, rust and scaling; use tools such as a steel brush, or hammer. Grind the flanges.

2

Perform a visual inspection.

3

Wash with alkaline solution in hot water at 80 °C for degreasing.

4

Perform the pickling (including neutralizing/rinsing of piping).

5

Dry by blowing with air, 1.5 times the nominal pressure.

6

Perform LFO or water flushing for long pipe lines.

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7

Blow with air after erection of the pipe system.

8

Perform the pressure and leak tests.

9

Fill the lines with nitrogen at a pressure of 0.5 bar(g), to prevent corrosion.

10 Fill the lines with gas. Postrequisites After startup, check the lines for leakage (natural gas leaks easier than air).

Cleaning TIG welded stainless steel piping

16.9.2

Procedure 1

Perform a visual inspection.

2

Perform pickling and passivation according to section 16.9.3.

3

Blow with compressed air.

4

Perform the pressure and leak tests.

5

Fill the lines with nitrogen if a flammable mixture is possible.

6

Fill the lines with gas. Postrequisites After startup, check the lines for leakage (natural gas leaks easier than air). Blowing of the lines is done as follows: ● First with an open valve ● Then by sequentially opening and closing the valve several times so that there will be pressure shocks.

16.9.3

Storing and cleaning of stainless steel pipes If the stainless steel alloy is correctly selected and stored, there should not be any corrosion. Sea water, or water in general with a high content of chlorides will speed up the corrosion, particularly water standing still in pipes. The risk of this is higher in “normal” stainless steel grades (304, 316) than in high performance stainless steels. This risk is reduced by choosing a higher grade of stainless steel or by pickling the pipes. Place stainless steel pipes in a dry and ventilated location, if they are to be stored for a long period. If the pipes are greased, use a non-chlorinated solvent to remove the grease. This must be done to avoid leaving residue of chlorine ions. The chlorine ions can initiate crevice, pitting and stress corrosion.

Do not clean stainless steel pipes with any type of metallic wire brush other than stainless steel. Avoid grinding or polishing with grinding wheels or belt sanders, as they tend to overheat the surface to the point where corrosion resistance cannot be restored even with pickling. If a very heavily contaminated stainless steel surface is to be cleaned by sandblasting, ensure that the sand is truly clean (not recycled). Another method is glass ball blasting. Do not use blasting methods that could roughen the surface. Do not use steel shot blasting.

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Pickling After the pipe fabrication (welding, cutting, etc.), pickle the pipes in order to get the best corrosion resistance. At least all welds shall be pickled. The pickling can be done by immersion or locally by pickling paste. Pickling paste is sold at least by the stainless steel manufacturers (e.g. Avesta Polarit). Different types of paste used for different grades of stainless steel. The nitric-HF [1] pickling method is the most widely used and effective method (10% HNO3, 2% HF and the rest water at 50–60 °C). Always pickle the pipes if they are sandblasted.

NOTE After pickling, a new, intact oxide layer is formed on the pipe surface. The oxide layer prevents the pipe from corrosion.

Passivation If pickling is not performed, the pipe must be passivated or treated by acid cleaning. Passivation is carried out similar to pickling, but the active component is simply 18–30% nitric acid (HNO3) at room temperature. The passivation time is 20–60 minutes. Small parts can be passivated by immersion and large parts can be sprayed or brushed. The parts must be rinsed thoroughly in water after the treatment.

NOTE Passivation will only strengthen the old oxide layer.

CAUTION Environmental risks and health hazards must be considered when working with acid solutions.

Flushing of compressed air systems

16.10

In addition to the information in section 16.1 for the compressed air system, perform the final cleaning of the compressed air pipes prior to commissioning as follows:

NOTE Clean the compressed air system before pressurizing the engine or any auxiliaries.

CAUTION Make sure that the personnel are aware that the compressed air system will be blown clean. Inform everyone possibly concerned and close off the area by means of zebra (warning) tape. Procedure

[1]

1

Once the pressure test of the system is completed successfully, close the isolating valve from the outlet of the starting air bottle manifold and the instrument air dryer.

2

Disconnect the flexible hoses for the starting air and instrument air at the engine inlets and fasten the hoses firmly with rigid steel clamps to the closest structures.

HF = Hydrofluoric acid

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The discharge from the hoses must be directed in such a way that the blowing air stream will not be able to damage or disturb the surroundings.

16.11

3

Hammer the weld seams thoroughly throughout the piping system.

4

For the starting air system: Open up the isolating valves for some fifteen seconds and close the valves again. Repeat this procedure one more time to obtain the best results. The same procedure applies to auxiliaries connected to compressed air.

5

For the compressed air system: Open and close all valves several times.

Flushing of cooling water system NOTE Perform the pressure testing and record the results before flushing the system.

NOTE The flushing pump arrangement is not delivered by Wärtsilä.

16.11.1

Flushing the expansion pipes Flush the expansion pipes with water until they are clean from debris. Drain the expansion system and completely clean the bottom of the expansion tanks.

16.11.2

Flushing the pipes between pipe module and radiators Before the flushing with water, clean the bigger pipes by hand. The pipe module and the radiators do not need to be flushed. Therefore, disconnect the pipes from the module and the radiators and build a pipe loop as shown in Fig 16-6. For the flushing, use an external flushing pump arrangement (e.g. by using the fire water pump) that has an adequate flow capacity and is equipped with strainers to collect the debris coming from the pipes during the flushing procedure.

Fig 16-6

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Flushing arrangement for cooling water pipes

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16. Cleaning and flushing of external piping

Flushing the whole cooling radiator system When the pipes between the pipe module and the radiators are clean, reconnect the pipes to the pipe module and the radiators. Install running filters on HT and LT inlet pipes to the engine. Fill up the whole system with untreated water. Run until the engine is warm; then shut down the engine. Check the running-in filters. If no debris is found in the filters or in the expansion tanks, the system can be considered clean. Drain all water from the system and refill it with chemically treated water. Remove the running-in filters at the first 50 hours service interval of the engine.

16.11.4

Flushing the pipes between pipe module and cooling tower Cooling tower installations will basically follow the same principle as radiator installations. Procedure 1

Disconnect the pipes from the pipe module.

2

Install a mesh in the pipe end of the return pipe to the cooling tower basin. This mesh is for trapping the debris.

3

Use the cooling tower pumps. There is no need to install a separate flushing pump.

NOTE Protect the pumps with adequate strainers on the suction side during the flushing sequence.

Flushing the whole cooling tower system

16.11.5

Procedure 1

When the pipes between the pipe module and the cooling towers are clean, reconnect the pipes to the pipe module.

2

Fill up the primary circuit (engine and pipe module) with untreated water.

3

Run until the engine is warm; then shut down the engine.

4

Check the running-in filters. If no debris is found in the filters or in the expansion tanks, the system can be considered clean.

5

Drain all water from the primary circuit and refill it with chemically treated water.

6

Remove the running-in filters after the first 50 hours service interval of the engine.

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Installation Manual

Cleaning of steam boilers, steam drums, feed water tanks and related water spaces Procedure 1

The storage, sea transportation or improper covering or protection of the equipment may result in extensive corrosion of the water spaces. Tanks and vessels can be either sandblasted or pickled, depending on which method is most applicable on location. The information about neutralizing and rinsing of pickled items and sand blasting in section 16.2.5 and section 16.4 also applies to the cleaning of the items specified in the title of this chapter. Excessively corroded coil-type boiler sections can be pickled and neutralized in a normal fashion as stated earlier. The priority is to conduct a blow-through of the coil-type boiler with steam, if available. Steam treatment provides a well acceptable result.

2

Tube boilers may require cleaning of the tubes or the furnace, or both. The priority is to blow both sides clean with steam to ensure the gentlest treatment. If steam is not available at the plant, a portable steam generator can be rented locally in many cases. Furthermore, if an auxiliary boiler container is provided in the scope of supply, its steam generation should be considered for cleaning purposes.

3

After mechanical cleaning, a clean boiling procedure must be executed before taking the boiler into use, according to a specific detailed program provided by the supplier. Exhaust gas boiler manufacturers recommend cleaning with boiler chemicals mixed to double concentration, compared to the normal concentration for own consumption boilers. This step is an integral part of commissioning procedure that must be documented. The procedure is linked to the validity of the warranty.

NOTE Flush steam and condensate lines before taking them into use. In plants with steam turbines or other equipment that are sensitive to impurities, the flushing of the live steam line has to be approved by the turbine (equipment) manufacturer before taking the equipment into use. 4

Boiling-out of the boiler shall be done: ● before initial start of full output boilers ● in case of oil in the waterside ● in case of heavy corrosion. There are two methods of cleaning: alkaline boil out and acid cleaning.

Alkaline boiling-out

16.12.1

Procedure 1

Before a full output boiler is put in service or if there is oil in the water, boil out the impurities. Fill the boiler to the normal level with softened water. The water must be properly treated and deaerated to guarantee minimum formation of scaling as soon as the boiler is set in operation.

2

16-38

Dissolve the chemicals entirely prior to pouring the mix into boiler. Fill the boiler first half full with soft water and then top it up with the chemical blend.

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Add the chemical solution through the manhole or the chemical feed connection. Any of the following combinations will give a proper cleaning result: ● Trisodium phosphate + caustic soda, 2500 ppm + 2500 ppm ● Trisodium phosphate + caustic soda, 5000 ppm + 500 ppm ● Trisodium phosphate + caustic soda + soda ash, 3 × 1500 ppm ● Caustic soda + soda ash, 3000 ppm + 3000 ppm. 3

Blow down the boiler or each piece of the system every 8 hours. The amount of blown water equals half the sight glass. Add feed water if required, to keep within the limits. After every blow down, add the chemical mix to replenish the concentration.

4

Continue boiling for 40 hours. Take condensate samples through the sample points to ensure that impurities are no longer present.

Acid boiling-out

16.12.2

Use this procedure when rust or mill scale is known to exist to a high degree in the boiler. Normally, acid boiling is not required for new boilers. Use a solvent composition of 5% hydrochloric acid, 0.5% ammonium biflouride, and 0.1% inhibitor. Procedure 1

Heat up the boiler until the boiler metal reaches a temperature of 70–80 °C. Control the temperature with the bypass damper in the exhaust gas outlet.

2

Fill up the boiler with solvent solution of about 65 °C. Prepare this solution by diluting the chemicals with warm water.

3

Let the boiler soak six hours with the acid solution.

4

Ensure that the vents are open. The vents must be open because hydrogen gas is evolved through the reaction between steel surfaces and acid. Avoid all open flame and sparks because the gas may ignite. If indoors, run the boiler house fans to keep the space well ventilated.

5

Drain the system by gravity and boost the draining with compressed air, if needed. Open the venting valves while draining.

6

Rinse the boiler with soft water. a Fill the boiler with soft water. Open the venting valves while filling. Shut the valves and run the feeder pump to get it rinsed. b Shut the vent valves. c Run the feed pump for rinsing.

7

Open the drain in the bottom of the boiler slightly and continue filling from the top with soft water. Let the system run until you consider that a full cycle of fresh water has gone through. The boiler is rinsed as soon as the pH value of purged water exceeds 5.

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16.12.3

Installation Manual

Neutralization boil-out Procedure 1

Fill up the boiler with a 1% sodium carbonate solution to the normal level. Run the boiler feeder pump and top up the boiler to normal operating level.

2

Raise the pressure to the normal operating level and maintain it for approximately four hours.

3

Stop the heating, let the pressure drop to 1 bar and then drain the boiler.

16.12.4

Passivation Procedure 1

While the unit is still hot, fill it with a 0.5% sodium nitrite solution and let soak for one hour.

2

Drain the boiler.

Inspection, flushing and precautions

16.12.5

NOTE Never heat or fire boiler with exhaust gases while there is acid solvent in the unit.

Procedure 1

When the boiler has cooled down, inspect the steam drum and the boiler waterside surfaces. Remove any loose iron oxide or other scaling manually with a steel brush or flat chisel. Flush out the loose deposits with clean water. Do not damage the passivated layer.

2

Put the manholes back in place and close the access doors. The boiler is ready for normal service.

16.12.6

3

Store neutralizing boil out chemicals in a dry place prior to use.

4

Keep protective clothing available for those working with the process handling chemicals. Always use proper protection (rubber gloves, boots, aprons, and protective glasses).

5

Keep a record of the process and have it signed duly by both parties.

Boil-out of an oil-fired boiler The interior of oil-fired auxiliary boilers may have protective coatings that must be boiled out.

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16. Cleaning and flushing of external piping

Procedure 1

Fill up the boiler. a Prepare a 2.5-% mixture in a separate container. Normally, manufacturers suggest trisodium phosphate and caustic soda. b Fill the boiler with water. c Add the acid solvent to the top of the tubes.

2

Heat the boiler to the boiling point and let the boiling last for five hours.

3

Wait until the boiler has cooled down a to a safe level and drain the water to the sewage.

4

Rinse the tubes with high pressure water.

5

Perform a visual inspection to determine if the result is acceptable.

Cleaning of steam pipes and feed water pipes

16.13

Steam pipes that are not clean on the inside are to be pickled prior to the cleaning by steam blowing (see section 16.2). Feed water pipes are to be flushed with water only.

16.13.1

Cleaning the pipes between auxiliary boiler, steam header and exhaust gas boilers Prerequisites

CAUTION Make sure that the personnel are aware that the steam system will be blown clean. Inform everyone possibly concerned and close off the area by means of zebra (warning) tape. See the flow diagram, document number WDAAA196364. Procedure 1

Disconnect the pipes at the inlets to the boilers. Fasten them firmly to the closest structures with rigid steel clamps. Direct the discharge of the pipes in such a way that the blowing air stream will not be able to damage or disturb the surroundings.

2

Blow the steam beginning from the auxiliary boiler to the steam header and further on to the exhaust gas boilers. During this procedure, hammer the pipes in order to dislodge particles from the inside of the piping. Repeat this procedure several times. Let the temperature of the pipes go down between the blows.

16.13.2

Cleaning the steam pipes between header, pipe rack, consumers inside the power house and blow-down tank See the flow diagram, document number WDAAA196366.

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Installation Manual

Procedure 1

Disconnect the pipes at the inlets to the consumers. Fasten them firmly to the closest structures with rigid steel clamps. a Direct the discharge of the pipes in such a way that the blowing air stream will not be able to damage or disturb the surroundings. b Install an extra pipe loop at the pipe rack.

2

Blow the steam beginning from the auxiliary boiler to the steam header and further on to the pipe rack. During this procedure, hammer the pipes in order to dislodge particles from the inside of the piping. Repeat this procedure several times. Let the temperature of the pipes go down between the blows.

3

Plug the extra pipe loop at the pipe rack(s).

4

Open the valves to the consumers’ circulation pipe and start the clean blowing at the very back engine. Blow all steam pipes for the consumers.

5

Install an extra pipe loop at the end of the circulation pipe out to the consumers and blow the condense pipe line.

Cleaning the steam pipes between header, consumers outside the power house and blow-down tank

16.13.3

See the flow diagram, document number WDAAA196376. Procedure 1

Disconnect the pipes at the inlets to the consumers. Fasten them firmly to the closest structures with rigid steel clamps. The discharge of the pipes must be directed in such a way that the blowing steam stream will not be able to extract any items from the surroundings. Install an extra pipe loop between the main line and the condensate return line.

2

Blow the main and the condensate return lines. This procedure is to be repeated several times. At the same time the pipes are to be hammered in order to get possible particles to come off from the inside of the piping. Let the temperature of the pipes go down between the blows.

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3

Blow the steam lines to the consumers. If there is a loop in a tank, the loop shall also be blown by disconnecting the flange connection to the condensate line.

4

Install an extra pipe loop at the end of the steam and condensate lines and blow the whole piping system back to the blow-down tank.

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