Short Term Shutdown.pdf

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InstructionDocID: WDAAA262016Title: Short Term Shutdown

Revision: a

Created by: Jarkko Vettenranta / 25-Jan-2004 Status: Finalised

Finalised by: Jarkko Vettenranta / 06-Feb-2006 Pages: 1 (108)

Power Plants Project: -

Description: Preservation of Plant

Table of contents

1. Short-term shutdown........................................................................................4

1.1 General plant...............................................................................................4 1.1.1 Record keeping................................................................................................... 5

2. Genset................................................................................................................6

2.1 Genset standby procedures ......................................................................6 2.2 Genset shutdown procedures...................................................................7

2.3 Supervision of genset during shutdown ..................................................8

2.4 Maintenance of genset during shutdown.................................................9

2.5 Re-activation of genset after shutdown..................................................10

3. Auxiliaries........................................................................................................13

3.1 Fuel systems.............................................................................................13 3.1.1 Shutdown procedure......................................................................................... 13 3.1.2 Supervision during shutdown............................................................................ 18 3.1.3 Maintenance during shutdown.......................................................................... 18 3.1.4 Re-activation after shutdown ............................................................................ 19

3.2 Lube oil systems ......................................................................................24 3.2.1 Shutdown procedure......................................................................................... 24 3.2.2 Supervision during shutdown............................................................................ 27 3.2.3 Maintenance during shutdown.......................................................................... 28 3.2.4 Re-activation after shutdown ............................................................................ 28

3.3 Compressed air systems .........................................................................31 3.3.1 Shutdown procedure......................................................................................... 31

3.3.2 Supervision during shutdown............................................................................ 34 3.3.3 Maintenance during shutdown.......................................................................... 34 3.3.4 Re-activation after shutdown ............................................................................ 35

3.4 Cooling systems.......................................................................................36 3.4.1 Shutdown procedure......................................................................................... 37 3.4.2 Supervision during shutdown............................................................................ 39 3.4.3 Maintenance during shutdown.......................................................................... 40 3.4.4 Re-activation after shutdown ............................................................................ 42

3.5 Combustion air systems..........................................................................44 3.5.1 Shutdown procedure......................................................................................... 44 3.5.2 Supervision during shutdown............................................................................ 45 3.5.3 Maintenance during shutdown.......................................................................... 45 3.5.4 Re-activation after shutdown ............................................................................ 45

3.6 Exhaust gas systems ...............................................................................46 3.6.1 Shutdown procedure......................................................................................... 46


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3.7 Waste treatment systems ........................................................................48 3.7.1 Shutdown procedure......................................................................................... 48 3.7.2 Supervision during shutdown............................................................................ 51

3.7.3 Maintenance during shutdown.......................................................................... 53 3.7.4 Re-activation after shutdown ............................................................................ 53

3.8 Water treatment systems.........................................................................57 3.8.1 Shutdown procedure......................................................................................... 57 3.8.2 Supervision during shutdown............................................................................ 59 3.8.3 Maintenance during shutdown.......................................................................... 60 3.8.4 Re-activation after shutdown ............................................................................ 60

4. Heat recovery systems...................................................................................64

4.1 Steam generation system ........................................................................64

4.1.1 Shutdown procedure......................................................................................... 65 4.1.2 Supervision during shutdown............................................................................ 71 4.1.3 Maintenance during shutdown.......................................................................... 73 4.1.4 Re-activation after shutdown ............................................................................ 75

4.2 Steam consumer system .........................................................................81 4.2.1 Shutdown procedure......................................................................................... 81 4.2.2 Supervision during shutdown............................................................................ 82 4.2.3 Maintenance during shutdown.......................................................................... 82 4.2.4 Re-activation after shutdown ............................................................................ 83

5. Emission control systems .............................................................................84

5.1 Shutdown procedure................................................................................84

5.2 Supervision during shutdown.................................................................85

5.3 Maintenance during shutdown................................................................85

5.4 Re-activation after shutdown ..................................................................86

6. Plant support systems ...................................................................................87

6.1 Cranes and lifting equipment ..................................................................87 6.1.1 Shutdown procedure......................................................................................... 87 6.1.2 Supervision during shutdown............................................................................ 88

6.1.3 Maintenance during shutdown.......................................................................... 88 6.1.4 Re-activation after shutdown ............................................................................ 89

6.2 Forklifts and other vehicles.....................................................................89 6.2.1 Shutdown procedure......................................................................................... 89 6.2.2 Supervision during shutdown............................................................................ 90 6.2.3 Maintenance during shutdown.......................................................................... 90 6.2.4 Re-activation after shutdown ............................................................................ 91

6.3 Emergency generator...............................................................................91

6.4 Workshop equipment...............................................................................92 6.4.1 Shutdown procedure......................................................................................... 92


6.5 Warehouse stock......................................................................................94


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6.6 Safety spare parts ....................................................................................95

6.7 Chemicals..................................................................................................95

6.8 Consumables ............................................................................................96

7. Electrical and control systems ......................................................................97

7.1 General shutdown procedures................................................................97

7.2 Supervision during shutdown.................................................................98

7.3 Maintenance during shutdown................................................................98

7.4 Re-activation after shutdown ..................................................................99

7.5 Control room.............................................................................................99 7.5.1 Panels............................................................................................................... 99 7.5.2 Operators interface ......................................................................................... 100 7.5.3 Computers ...................................................................................................... 100

7.6 Switch gears ...........................................................................................100 7.6.1 Low-voltage switchgear .................................................................................. 100 7.6.2 High-voltage switchgear.................................................................................. 100

7.7 Transmission system.............................................................................101 7.7.1 Transformer .................................................................................................... 101 7.7.2 Breakers ......................................................................................................... 101

7.8 DC system...............................................................................................102 7.8.1 UPS system .................................................................................................... 102 7.8.2 Batteries.......................................................................................................... 103

8. Civil ................................................................................................................104 8.1 Fire detecting..........................................................................................104

8.2 Fire fighting.............................................................................................105

8.3 HVAC .......................................................................................................105

8.4 Sewage and sanitary ..............................................................................106 8.4.1 Drainage ......................................................................................................... 106 8.4.2 Sewage treatment units .................................................................................. 106

8.5 Plant structure ........................................................................................107 8.5.1 Roads ............................................................................................................. 107

8.5.2 Fences............................................................................................................ 107 8.5.3 Roofs .............................................................................................................. 107 8.5.4 Windows ......................................................................................................... 108 8.5.5 Doors .............................................................................................................. 108


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1. Short term shutdown

1.1 General plant

! CAUTION! A power plant consists of complex and expensive equipment, and the owner ofthe power plant to be shutdown should be well advised to use the services of acompany specialising in this kind of work. Contact Wärtsilä Service for assistanceif you require the plant to be shutdown for a prolonged period of time.

The primary information that must be known is the length of time for which the plant will be

shutdown.

The short-term shutdown procedures described in this document, covers the requirement for

having the plant de-activated for a period not exceeding three (3) months. If the plant needs

to be de-activated for a period longer than this, it should be considered for the proceduresestablished for the preservation of plant.

NOTE!

Instructions for the preservation of the power plant are available from theOperation & Maintenance Manual department, but only as a general planningguide to help the power plant management plan and perform the activitiesnecessary for a long-term preservation of the plant.

Also the ambient conditions at site are important, and the environmental conditions that may

be expected during the period that the plant is de-activated, must also be known.The most favourable conditions are those where no frost needs to be taken into

consideration, surroundings are clean and free from dust, the relative humidity is below 50%,

etc.

The least favourable conditions are those with high humidity, salty air, ambient temperatures

that varies from freezing to very warm, dusty surroundings, etc.

! CAUTION!It is extremely important that the actual conditions for the shutdown is carefullyand thoroughly investigated before de-activating the plant, and that the

appropriate procedures are selected. Failing to do so may result in seriousdamages to the engines and other equipment, as well as problems when re-activating the plant again.

For shorter periods of de-activation during less favourable conditions, it may be preferred to

maintain the plant in a standby condition. For more information, refer to the Operating

Manual including genset’s standby procedures. A short version is also included in Chapter 2

Genset in this document.


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1.1.1 Record keeping

The shutdown of a plant requires documentation to keep track of the actions taken. For this

reason it is recommended to prepare a special shutdown folder to collect the information

collected during the shutdown of the plant, as well as log sheets prepared while supervising

the plant during shutdown.Also information about the maintenance performed on the units during the shutdown period

should be recorded. Forms must therefore be prepared and used when recording the activities

and actions taken during the preservation of the plant.

NOTE!

To have access to these records is very important when re-activating the plant.

The records should also include observations about major items that must be taken care of

before or when re-activating the plant.


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2. Genset

2.1 Genset standby procedures

NOTE!

In this section only the procedures for maintaining the genset in a ready- to-startmode has been taken into consideration.

During normal shut-down the following units will remain activated or in operation:

• Engine pre-lube pump

• Cooling system pre-heating unit

• Generator heaters

• All auxiliary systems should be activated and in ready-to-start mode

When the engine is shut down for a prolonged period of time, the following actions should

be taken.

Every second day

During the shut-down period the function of the engine pre-lube pump, pre-heating unit and

the generator winding heaters should be checked and the crankshaft rotated to a new position

using the turning gear.

Weekly

Once a week the engine must be primed, crankshaft rotated using turning gear (with fuel

rack in “No-fuel position” and with indicator valves fully open).

1. Keep watch on the indicator valves to check if any water is discharged. Close theindicator valves and start the engine to check that every function is in order.

2. Run the engine for about ten minutes without loading and check that all systemsfunction correctly.0.

Monthly

Once per month a load trial should be performed:

1. Make ordinary preparations and check that the engine starts normally. Apply load (75-100%) to engine.

2. Run the engine for at least one hour and check that all pressure and temperature readingsare at normal values. Check that alarms and monitoring systems function correctly andthat no false alarm is indicated.

3. Reduce load and continue running for at least ten minutes before engine is stopped.0.


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2.2 Genset shutdown procedures

Before shutting down an engine operating on heavy fuel oil (HFO) for de-activation, it is

necessary to switch over to light fuel oil (LFO) operation. The engine must have run on LFO

long enough to remove the heavy fuel oil that normally is present in the fuel system.

For all types of engines it is important to check the concentration of additives in the coolingwater, and it would be recommended to add additives to ensure that the concentration is kept

at the higher level, or even slightly higher, before stopping the engine.

It would also be recommended to check the total base number (TBN) of the lubrication oil in

the engine crankcase. If the TBN is low it would be recommended to change the oil (either

totally or partially) to increase the TBN value during the storage period.

NOTE!

If the oil shall be changed, or is close to a normal oil change, then it would berecommended to perform the oil change when de-activating the engine. Do notlet the old oil remain in the engine during the shutdown period only to be changedwhen re-activating the engine. It is far better to have the engine stored with newoil than with old and already contaminated oil.

NOTE!

The engine should be run up to rated speed and to correct operatingtemperatures on the new oil before stopping it for de-activation to ensure that theinternal parts have been treated with the fresh oil. If the oil only has been toppedup it is still important to run the engine before de-activating it to ensure that the oilin the crankcase is properly mixed and that the improved oil has been circulatedthrough the engine system.

After having stopped the engine for de-activation, it should be secured to prevent accidental

start. This includes the following:

• Close and lock the engine start air supply valve.

• Close and lock the engine control air supply valve.

• Drain the engine start air system and lock the drain valve in open position.

NOTE!

To prevent that humidity enters the engine compressed air system, it would berecommended to place a plastic cover over the drain outlet from the valve. It will prevent humid air from entering the system, yet it would easily blow off if thesystem would become pressurised.

• Engage the turning gear.

NOTE!

If the engine is equipped with indicator valves then these shall remain closedduring the de-activation period, and only be opened when the engine crankshaftis rotated.


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• Proceed to shut down all auxiliary equipment (refer to separate instructions provided in

Chapter 3 Auxiliaries in this document).

• Also shut down the engine pre-lube pump and the cooling system pre-heating unit. The

generator anti-condensation heaters should remain in operation.

!CAUTION!

This assumes that the genset is de-activated under favourable ambientconditions and that no heating of the engine is required (to prevent freezing). The

storage temperature should preferably range from 10 ° C to 50 ° C with a maximumair humidity of 75%. If air humidity is more than 75%, the generator must be provided with good internal ventilation. The anti-condensation heaters must beenergised to keep the temperature of the machine above the dew point of theambient air to prevent condensation of moisture. The internal ventilation is alsonecessary to prevent overheating should the ambient temperature be above

50 ° C, this is especially important when the anti-condensation heaters areactivated. The self-lubricated bearings must be filled with oil.

The following openings shall be securely covered:

• Combustion air inlet (Refer to Combustion air systems for information).

• Exhaust gas outlet (Refer to Exhaust gas systems for information).

• Crankcase ventilation outlet (if vented to the atmosphere).

! CAUTION!These outlets shall remain covered until the engine is re-activated. It is alsoimportant to place a note with the following (or similar) text at a conspicuous

place on the engine. “The covers placed on the combustion air inlet, exhaust gasoutlet and the crankcase ventilation outlet must all be removed before attemptingto start the engine!”

2.3 Supervision of genset during shutdown

! CAUTION!These checks should be performed when possible (during a shutdown with personnel at the site) but not less than once a week.

A simple shutdown of the plant should not exceed three (3) months, and it is assumed that

the normal operating and maintenance personnel are available at site during the shutdown

period.

This would be beneficial, as personnel with experience of the plant operation would be

responsible for the necessary supervision of the plant and the shutdown equipment.

The supervision of the shutdown genset would normally be limited to checks to confirm that

the protective covers/seals are intact, that the coolant and lube oil levels remain the same.


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NOTE!

There should be no increase and no decrease. Both are conditions that wouldhave to be investigated should they occur. It is also important to properly record

these reading to detect changes should they occur. This can be done also by putting a non-permanent mark on the sight glass or dipstick – or by writing up theactual reading close by the place where the reading is taken.

The external parts of the genset shall also be inspected to detect corrosion, leakage or other

detrimental conditions that could cause damage to the engine and related equipment.

It is also important to check that the generator anti-condensation heaters are activated (power

supplied) and is functioning as intended. If an internal ventilation system has been installed

(in places with humidity over 75%) also this system must be controlled to ensure proper

function.

The drain valve for the combustion air intake silencer and the exhaust gas silencer shall be

opened to check for the presence of condensate. Drain out all condensate and then close the

drain valve.

! CAUTION!If an excessive amount of condensate is found, it will be necessary to investigatehow this humidity has entered the system, and to rectify the condition(s) that hascaused it.

2.4 Maintenance of genset during shutdown

During the shut down period check the function of the engine pre-lube pump, pre-heatingunit and the generator winding heaters and rotate the crankshaft to a new position using the

turning gear.

! CAUTION!These actions should be performed once a week if possible (during a shutdownwith personnel at the site) but not less than once a month.


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Procedure

The following procedure is recommended:

1. Prime the engine lube oil system by starting the pre-lube pump.

2. Start pre-heating circulation pump (heater deactivated).

3. Open indicator valves.

4. When the prelube pump has been in operation for at least five minutes, activate theturning gear with fuel rack in No-fuel position and with indicator valves fully open and

turn the engine 4-5 complete revolutions. Make sure that the turning is stopped in a

position where the shaft has a new resting point.

5. Keep watch on the indicator valves to check if any water is discharged.

6. Close the indicator valves.

7. Shut down the pre-heating circulation pump. It should have been in operation for at leastfive [5] minutes total.

8. Shut down the prelube pump. It should have been in operation for at least fifteen [15]minutes total. 0.

NOTE!

If the engine is equipped with a lube oil separator and it is possible to activate thisunit (lube oil heater can be activated), it would be recommended to run theseparator prior to turning the engine according to the instructions above. Theseparator should be run sufficiently long to ensure that all oil in the enginecrankcase has been treated in the separator at least once. However, note thatthis would be not be necessary it the engine has been shutdown on new oil.

2.5 Re activation of genset after shutdown

Before re-activating the genset it is important to check the shutdown log to verify that no

conditions exists that must be taken care of/rectified prior to starting the engine.

NOTE!

It is assumed that the auxiliary systems have been checked and activated asrequired. Refer to instructions given in Auxiliaries.


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Procedure for re-activation

The following procedure is recommended:

1. Start pre-heating circulation pump.

2. Check that the pump and the heater are well vented before starting the pump.

3. Check the operation of the pump (no noise, heated bearings, leaking packing box orother leaks, etc.)

4. Activate the heater. If not an electrical heater is used, then the correct heating mediamust be available before attempting to activate the genset.

5. Operate the pre-heating unit until the jacket water has reached the correct temperature

(normally about 70°C). Check the engine instruction manual for the recommended

temperature.

NOTE!

It can take several hours before the coolant and the engine is heated up to the

proper temperature, and it is recommended to start pre-heating the coolant theday before the planned activation of the genset.

If the engine is equipped with a lube oil separator, then this unit should be started early

enough to enable the separator to treat the oil in the engine crankcase at least once. It would

also be beneficial if the lube oil was heated to a temperature of about 40°C before starting

the engine.

!

CAUTION!

If the engine is equipped with internal heaters (electrically powered) then these

should not be activated before the pre-lube pump has been started to providesome circulation of the oil in the crankcase which can help prevent overheating ofthe oil surrounding the heating elements.

6. Prime the engine lube oil system by starting the pre-lube pump.

7. Check that the pump is well vented before starting.

8. Check the operation of the pump (no noise, heated bearings, leaking packing box orother leaks, etc.)

9. Open the indicator valves.

10. When the pre-lube pump has been in operation for at least five minutes, activate theturning gear with fuel rack in No-fuel position and with indicator valves fully open and

turn the engine 4-5 complete revolutions. Make sure that the turning is stopped in a

position where the shaft has a new resting point.

NOTE!

Keep watch on the indicator valves to check if any water is discharged.

11. Remove the turning gear.

12. Remove all covers installed on the combustion air inlet, the exhaust gas outlet, thecrankcase ventilation outlet and the drain outlet from the start air system.

13. Activate the engine start air system.

14. Remove the locks on the start air, control air and drain valves.

15. Slowly open the main start air valve.


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16. Close the drain valve when no more condensate is discharged from the system.

17. Open the main start air valve and the control air supply valve. 0.

Test run

Before actually starting the engine, the following checks and activities should be performed:

• Check pre-lube flow.

• Activate the starting air supply and run the engine for a few revolutions while keeping

the fuel linkage (emergency handle) in stop position and with the indicator valves open.

This eliminates the risk of water locks.

NOTE!

Keep watch on the indicator valves to check if any water is discharged.

• Close the indicator valves.

• Check that the automatic alarm and stop devices are set in start positions.

• Check that the fuel linkage is in work position and that it moves freely.

• Check power supply on electronic monitoring equipment in the control panels.

• Start the engine according to the procedures outlined in the Operating Manual or in the

engine instruction manual.

• Make ordinary preparations and check that the engine starts normally. Apply load (75-

100%) to engine.

Immediately after that the engine has started, the following should be checked:

• Check that all pressures and temperatures for lube oil, fuel oil, cooling water, charge air,

etc. are normal.

• Check the differential pressures over fuel oil filters, lube oil filters and the charge air

filtration unit.

• Check that the cooling system is properly vented (no air pockets).

• Check for leakages.

• Check the exhaust gas temperature after each cylinder. This gives an indication that all

fuel pumps are operating.

• Check the pressure in the engine crankcase (to detect blow-by, etc.).

• Check the speed indicator instrument (engine and turbo).

• Check the service time meter.

• Activate the automatic alarm and stop devices.

• Check the operation of the return fuel radiator cooler.

• Check alarm panel to verify that no alarms are active.

Run the engine for at least one hour.

Check:

• All pressure and temperature readings are at normal values.

• Alarms and monitoring systems function correctly and that no false alarm is indicated.

Reduce load and shut down the engine according to instructions in the Operating Manual orthe engine instruction manual.

The engine is now ready for normal operation.


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3. AuxiliariesA power plant is a fairly complex installation, and the amount of auxiliaries depends on the

size of the plant, the type of engines as well as the type of fuel used.

The instructions provided in this section are therefore very general in nature, and it is up tothe plant management to decide what information to use.

Refer to the Original Equipment Manufacturer’s (OEM’s) instructions available in the

station manuals for further information should this be required.

3.1 Fuel systems

The complexity of the fuel systems varies with the type of fuel used – the simpler ones using

light fuel oil (LFO) only, and the more complex systems are supplied for power plants using

heavy fuel oil (HFO), crude oil or biofuel.

Also natural gas can be used as fuel, but this type of fuel is not considered in these

instructions.

NOTE!

Due to additives and contaminants fuel oil do have a finite life that is generallyregarded to be about one (1) year in storage. This must be taken intoconsideration when planning for the shutdown of the power plant.

3.1.1 Shutdown procedure

Light fuel oil (LFO)

The LFO system does not generally require any special attention for a short-term shutdown.

However, the existing system should be investigated and carefully evaluated as to the most

suitable treatment for a short-term shutdown. For this purpose the following information

might be useful.

Unloading system

The connections at the unloading point should be covered and preferably locked to prevent

contamination of the inlet.

NOTE!

It is recommended to put a numbered seal on the connection. This would give anindication of unauthorised entry if the seal were found to be broken. Use a “seallog” to record the seal number.

If possible, have the unloading system full of LFO during the shutdown period as this can act

as corrosion protection.

Disconnect the power supply to the unloading pump unit. If the power supply is accessible,

that is, not installed in a lockable area, it is recommended to also lock the breaker in OFF

position.


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Transfer and storage system

1. Close and lock all outlet valves on the storage tanks including day tanks to prevent spillif a valve downstream is accidentally opened and also to prevent theft if the area is left

unguarded.

NOTE!

Also here it would be recommended to put a numbered seal on the valves inlocked position. Use a seal log to record the seal number.

2. Take soundings and record after having closed and locked all outlet valves.

If possible, have the transfer system full of LFO during the shutdown period as this can act

as corrosion protection.

3. Disconnect the power supply to the transfer pump unit(s). If the power supply isaccessible, that is, not installed in a lockable area, it is recommended to also lock the

breaker in OFF position.

4. Disconnect the power supply to the control system. If the power supply is accessible,that is, not installed in a lockable area, it is recommended to also lock the breaker in

OFF position. 0.

LFO feeder system

NOTE!

Feeder system is here a term used to describe the LFO feeder pump unit thatsupplies LFO to the booster unit upstream of the HFO/LFO change over valve.However, if the engine is designed to operate on LFO only, then the LFO feeder

system will also be the Fuel supply system.

The genset should have been shutdown on LFO, and the fuel supply system should be left

full of LFO during the shutdown period as this can act as corrosion protection.

Disconnect the power supply to the feeder pump unit(s). If the power supply is accessible,

that is, not installed in a lockable area, it is recommended to also lock the breaker in OFF

position.

If the LFO supply system is equipped with a radiator-cooling unit in the return fuel system,

this should be covered with a tarpaulin to protect it from atmospheric contamination (dust,

leaves, etc.)


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Fuel supply system

NOTE!

The fuel supply system installed downstream of the HFO/LFO change over valveis designed to suit the main fuel used at the power plant – be it crude oil or some

type of bio fuel. If LFO is used as the main fuel than this information can bedisregarded and only the information given in LFO feeder system would apply.

As the genset should have been shutdown on LFO and left with LFO in the supply system,

this then also includes the booster unit, the engine pump and filter unit, as well as the engine

and any other equipment installed in the main fuel supply system.

1. Shut down each unit in the fuel supply system according to the operating instructions.

2. Empty all fuel collection tanks (leak fuel tank, ventilation tank, etc.) before shuttingdown the control system and the power supply.

3. Shut down the control system.

4. Disconnect 0.

• Power supply to the booster unit

• Engine pump and

• Filter unit

• Other units installed in the fuel supply system.

If the power supply is accessible, that is, not installed in a lockable area, it is recommended

to also lock the breaker in OFF position.

Heavy fuel oil (HFO)

The information given regarding the HFO system will also in general apply to systems using

Crude oil and bio fuels. The main item to consider is the viscosity of the oil, and lighter oilsthat will remain liquid at normal temperatures without heating does not generally require any

special attention for a short-term shutdown. Refer to the instructions given for LFO.

NOTE!

The main item that must be taken into consideration during a short-termshutdown is that the trace heating of the fuel system will be deactivated. Theinstructions below assumes that the trace heating for the fuel pipes and units willbe deactivated as soon as the fuel has been drained from the system/units.

This makes it necessary to investigate and carefully evaluate systems using fuels with a

higher viscosity, or using fuel that require heating or other forms of treatment to be

transferable. This shall be done with the aim of finding the most suitable treatment for a

short-term shutdown.

For this purpose the following information might be useful.


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Unloading system

1. The connections at the unloading point should be covered and preferably locked to prevent contamination of the inlet.

NOTE!

It is recommended to put a numbered seal on the connection. This would give anindication of unauthorised entry if the seal were found to be broken. Use a seallog to record the seal number.

2. The unloading system should be drained from HFO during the shutdown period.

NOTE!

For heavier fuel the unloading procedure would normally include a cleaning of thesystem. This is done by forcing a device made of rubber (a “pig”) through thesystem. This “pig” is pushed through the pipes using compressed air, and acts to

push out the fuel remaining in the pipe system. This is a procedure that is particularly important to use before a shutdown.

3. Disconnect the power supply to the unloading pump unit. If the power supply isaccessible, that is, not installed in a lockable area, it is recommended to also lock the

breaker in OFF position. 0.



NOTE!If possible, it may be beneficial to transfer the contents of the buffer tanks and theday tanks into one of the main storage tanks, as this could reduce the need forheating as well as the need for circulation of the contents in the tanks.

NOTE!

Storage tanks containing crude oil or bio fuel may also require having thecontents of the tank circulated continuously. Fuel oils with a high viscosity or fuelthat will solidify at normal ambient temperatures checked according to themanufacturer’s instruction.

2. Close and lock all outlet valves on the storage tanks (including buffer tanks and daytanks) to prevent spill if a valve downstream is accidentally opened.

3. The HFO system should be drained during the shutdown period. For fuels that requireheating to be transferable it would be recommended to empty the system by forcing a

“pig” through the pipes.

4. Disconnect the power supply to the transfer pump unit(s). If the power supply isaccessible, that is, not installed in a lockable area, it is recommended to also lock the


5. Disconnect the power supply to the control system. If the power supply is accessible,

that is, not installed in a lockable area, it is recommended to also lock the breaker inOFF position. 0.


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Treatment system

NOTE!

For the normal HFO fuel oil operated power plant, the treatment system mainlyconsists of the separator units required for the purification of the fuel oil.

Generally these units would not need any special treatment for a short-term shutdown not

exceeding three months. However, refer to the manufacturer’s instructions for information

(Alfa Laval does not require any special precautions if the shutdown period is less than six

months).

1. The fuel system within the treatment unit should be drained including the HFO heater.

2. The separator unit shall be cleaned and oiled internally as well as externally to preventcorrosion.

NOTE!

If the separator units may be exposed to vibrations (heavy traffic, etc.) it would berecommended to remove the separator bowl from the unit. It should be placed onwood boards and be protected against corrosion. Also the separator spindlewould require corrosion protection if the bowl were removed.

3. Empty the sludge tank as far as possible before shutting down the heating of the tank. 0.

HFO feeder system

NOTE!

The feeder system is here a term used to describe the HFO feeder pump unit thatsupplies HFO to the booster unit upstream of the HFO/LFO change over valve.This system is actually a part of the HFO supply system, but for these instructionsit is considered a separate system mainly since it will not be flushed with LFOduring shutdown of the genset.

1. The HFO system should be drained during the shutdown period – all the way to the partof the system that is filled with LFO (normally the 3-way change over valve at the

booster inlet). For fuels that require heating to be transferable it would be recommended

to empty the system by forcing a “pig” through the pipes.

2. Disconnect the power supply to the feeder pump unit(s). If the power supply isaccessible, that is, not installed in a lockable area, it is recommended to also lock the

breaker in OFF position. 0.

Fuel supply system

NOTE!

The genset should have been shutdown on LFO, and the fuel supply systemshould be left full of LFO during the shutdown period as this can act as corrosion protection. Refer to Fuel supply system in 3.1.2 Supervision during shutdown.


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3.1.2 Supervision during shutdown

Light fuel oil system (LFO)

The supervision of the LFO is fairly easy, and consists mainly of the following:

• Check the contents of the main storage tanks and the day tanks. If the tanks are equippedwith a mechanical level indicator this should also be checked regularly.

NOTE!

It would be advisable to put a removable mark at the level where the system wasshut down. This is a simpler way to keep track of level changes than taking areading and comparing this to reading made previously.

• Drain out a sample to check if the tank contains water. Any water present should be

drained out as it might permit biological contamination to propagate in the tank.

Check:

• Temperatures in the tank. Record or make notes if found to be excessive in either

direction – too hot or too cold.

• All seals (if used) that they have remained intact.

• All pipes and flange connections for leakage.

• Pumps for leakage (flanges and shaft seal).

• Corrosion protection where applied (mainly pump shafts, valves spindles, actuator

shafts, etc.)

• Any other unusual condition noticed during the inspection.

Heavy fuel oil system (HFO)

NOTE!

The actions described in Light fuel oil system (LFO) above are performed also forthe HFO system.

In addition to this, the following should be performed:

• If heat is supplied to maintain the temperature of the HFO, and then the function of this

heating system shall be controlled as shall the heat supply system.

• If the content of the tanks is circulated by an external pump system, then the function ofthis pump shall be controlled.

3.1.3 Maintenance during shutdown

NOTE!

The maintenance instructions given below is very general, and applicable to alltypes of fuel system, be it Light fuel oil, heavy fuel oil, crude oil or bio fuels. It isessential that the actual system and equipment is evaluated to establish theactual maintenance requirements. The information below should be viewed as

general information only.


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The maintenance during the shutdown period is mainly performed to prevent corrosion

damage, bearing damage and seizure of equipment. The following activities should therefore

be considered and performed whenever possible.

1. Inspect all pipe system and equipment for signs of corrosion. This is particularlyimportant for items/components exposed to the environment without sufficient

protection. Often parts of shafts are exposed. If possible they should be protected by

applying a soft corrosion protection, such as ordinary grease, Dinitrol or similar.

Whenever corrosion is detected it should be attended to, the corrosion removed and

additional corrosion protection applied.

2. Turn the shaft of rotating equipment to provide lubrication to the bearings and to givethem a new resting point. The shafts should be turned at least once a month (preferably

once a week) and rotated about 10-15 times.

! CAUTION!This is important to help prevent bearing failures when starting up the equipmentduring the re-activation of the plant.

3. Check all valves in the system for signs of corrosion, grease the valve stem and operatethe valve (open/close at least once) if possible without releasing liquid into other parts of

the system. This is particularly important for gate valves and globe valves. Butterfly

valves and ball valves may not benefit as much. 0.

3.1.4 Re-activation after shutdown

Light fuel oil (LFO)

NOTE!

Before re-activating the LFO system it would be recommended to perform athorough inspection of the system to detect any sign of leakage, corrosion orother signs of damages.

The system should be filled with LFO and provided that it has been supervised/maintained

properly during the shutdown it should be possible to re-activate without any problems.

However, the following activities would be recommended to ensure that the re-activation

proceeds smoothly.

Unloading system

The unloading system would need to be re-activated first when new fuel oil arrives at site.

1. Check that the unloading pump’s shaft rotates freely.

2. If possible, vent the pump- and strainer housing.

! CAUTION!The pump should not be permitted to run dry, and if the pump has been drainedof oil during the shutdown period it would be beneficial if possible to have theunloading system filled with oil from the tanker truck before starting it.

3. Activate the power supply and “jog” the pump to ensure that it is operating properly.

4. Open valves according to the list of manual valves available in the operatinginstructions.

5. Start the unloading according to the instructions in the operating manual


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Fuel supply system

NOTE!

Normally the LFO system is used as an auxiliary system, and the main fuel mightbe heavy fuel oil (HFO), Crude oil or biofuel. If so the fuel supply system will

contain several other units that must be started up when re-activating the plant.

The fuel supply system should be set to operate in LFO mode (if shut down on LFO as

instructed). If the operation instructions have been followed this also means that the trace

heating of the units are shut down, the heaters are deactivated and the piping system as well

as all units are still filled with LFO.

Each unit installed in the system should be re-activated according to the manufacturer’s

instruction. However, the general information below might be useful to consider:

1. All valves shall be opened according to the list of manual valves available in theoperating instructions.

2. All pump housings, strainer/filter housings and heaters shall be vented and completelyfilled with LFO.

3. Check the shafts for rotating equipment moves freely.

4. Activate the power supply and “jog” all pumps to ensure that they are operating properly.

5. Start all units in accordance with the instructions in the appropriate operating manual.

6. Check all units carefully to ensure that they are operating properly (no noise, vibrations,leaks or overheated bearings).

7. Check the function of the alarm system.

8. Vent the system piping carefully including the fuel system on the engine.

9. Activate all fuel collection tanks (leak fuel tank, ventilation tank, etc.) including all unitsinstalled in such systems (pumps, level control and ventilation fans). 0.

Heavy fuel oil (HFO)

NOTE!

The information given regarding the HFO system will also in general apply tosystems using crude oil and biofuels. Before re-activating the HFO system itwould be recommended to perform a thorough inspection of the system to detect

any sign of leakage, corrosion or other signs of damages including damage to theinsulation.

! CAUTION!The main item that must be taken into consideration is that the system cannot beactivated unless the trace heating systems can be activated first. That is, heatmust be available either in the form of electric power for electrical trace heatingsystems, or steam for steam-heated systems.

The instructions below assume that the trace heating for the fuel pipes and units has been

activated as part of the re-activation of the heat consumer system.


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Unloading system

The unloading system would need to be re-activated first when new fuel oil arrives at site.

1. Activate the trace heating of the system and the units installed.

2. Check that the unloading pump’s shaft rotates freely.

3. If possible, vent the pump- and strainer housing.

! CAUTION!The pump should not be permitted to run dry, and it would be beneficial if possible to have the unloading system filled with oil from the tanker truck beforestarting it.



6. Start the unloading according to the instructions in the operating manual.

NOTE!

Since the pipe system has been drained, it is important to vent all high parts ofthe system to prevent air pockets that can interfere with the operation.

7. Check the pump carefully to ensure that it is operating properly (no noise, leaks oroverheated bearings). 0.


1. Drain out any water that may be present in the main storage tanks.

2. Activate the tank heating system (main storage tanks and the buffer tanks).

3. Activate the trace heating of the system and all units installed.


5. Vent the transfer pumps housing and the suction strainer.

!CAUTION!

The pump should not be permitted to run dry, and it is necessary to ensure thatthe pump is filled with oil before starting it.

6. Check that the transfer pump’s shaft rotates freely.


8. Activate the power supply to the control system.

9. Start the transfer system according to the instructions in the operating manual.

10. Vent the heater on the transfer pump unit, and activate it when filled with oil.

11. Check the pump carefully to ensure that it is operating properly (no noise, leaks oroverheated bearings).

12. Check that the control system function properly by stopping the pump oropening/closing a 3-way valve at high level and starting it at low level.

13. Check the function of the alarm system. 0.


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Treatment system

NOTE!

If the separator has had the bowl removed for the shutdown, then it must becleaned and re-assembled before the treatment system is re-activated.

1. Drain out any water that may be present in the buffer- and day tanks.

2. Activate the tank heating system (buffer tanks, day tanks and the separator sludge tank)



5. Vent the separator feeder pumps housing and the suction strainer.


7. Activate the power supply and start the separator unit according the instructions in the

operation manual.

8. Vent the separator fuel oil heater, and activate the heater when filled with oil.

9. Check the separator carefully to ensure that it is operating properly (no noise, vibrations,leaks or overheated bearings).


HFO feeder system

NOTE!

As earlier explained, the feeder system is here a term used to describe the HFOfeeder pump unit that supplies HFO to the booster unit upstream of the HFO/LFOchange over valve.



3. Vent the feeder pumps housing and the suction strainer.

!CAUTION!

The pump should not be permitted to run dry, and it is necessary to ensure thatthe pump is filled with oil before starting it.


5. Activate the power supply and start the feeder pump unit according the instructions inthe operation manual.

6. If the feeder unit is equipped with a heater, then this heater should be vented. Activatethe heater when filled with oil.

7. Check the feeder carefully to ensure that it is operating properly (no noise, vibrations,leaks or overheated bearings).



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Fuel supply system

The genset should have been re-activated on LFO, and the fuel supply system should now be

full of LFO. This includes the booster unit, the engine pump and filter unit, the engine itself

as well as any other units/equipment installed in the fuel supply system.

NOTE!With the engine running on LFO and with the HFO system activated, the processof changing over to the main fuel may be started. Refer to the operatinginstructions for information about correct procedure.

3.2 Lube oil systems

The complexity of the engines lubrication system varies with the type of fuel used – the

simpler systems are supplied for engines operating on clean fuel only (light fuel oil, natural

gas, etc.). The more complex systems are supplied for power plants using heavy fuel oil

(HFO), crude oil or biofuel. These fuels produce more contamination and the lubricating oil

in the engine crankcase needs more efficient treatment to maintain it in good condition.


Refer also to the shutdown routines described for the genset in 2.2 Genset shutdown

procedures.

Lube oil circulation system

The lube oil circulation system is normally shut down when the engine is stopped (engine

driven circulation pumps). If a separate circulation pump is used, then this shall be stopped

after having the engine cool down (normally a part of the automatic shutdown procedure).

The lube oil system can then be left intact, as it also will be included in the routines

established for the genset. However, there are certain conditions that should be considered,

such as:

If the oil shall remain in the engine, it would be recommended to test the TBN value. If low

it would be recommended to add new oil to increase the TBN value of the oil in the

crankcase. If necessary, draw off some oil and replace it with new.

NOTE!

No more than 10% new oil may be added.

If the lube oil is near or at the end of the useful service life (oil change period) then the oil

should be changed. Do not wait with the oil change until it is time to re-activate the plant – it

is far better to have the engine shutdown with new oil than to have it standing still with

contaminated oil in the crankcase.

The same can be said for the lube oil filters. If they have been in service for a long time it

would be recommended to have the filters renewed at the same time the oil is replaced.

Clean the centrifugal filter on the engine. The filters is drained automatically and there is a

risk that the sludge collected in the filter may dry and break up causing problems when

starting up the filter again (vibrations and clogged lines).

Lube oil treatment system

Only engines operating on dirty fuels are equipped with a treatment system. This normally

consists of a lube oil separator unit and/or an automatic lube oil filtration unit.

The lube oil separator units generally would not need any special treatment for a short-term

shutdown not exceeding three months. However, refer to the manufacturer’s instructions for


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information (Alfa Laval does not require any special precautions if the shutdown period is

less than six months).

After shutting down the engine the separator should be left to operate to clean out eventual

contaminants if the old oil shall remain in the system. The separator should be left in

operation to permit the contents of the oil sump to be treated at least 3-5 times. Then the

separator can be shutdown and the heater deactivated.

The separator unit shall be cleaned and oiled to prevent corrosion internally as well as

externally.

NOTE!

If the separator units may be exposed to vibrations (heavy traffic, etc.) it would berecommended to remove the separator bowl from the unit. It should be placed onwood boards and be protected against corrosion. Also the separator spindlewould require corrosion protection if the bowl were removed.

• Empty the sludge tank as far as possible before shutting down the heating of the tank.

Also the trace heating (if installed) on lube oil and sludge lines would normally be

deactivated during a shutdown.

The automatic lube oil filtration unit generally does not need any special treatment for a

short-term shutdown not exceeding three months. However, refer to the manufacturer’s

instructions for information.

• After shutting down the engine the automatic lube oil filtration unit shall be shutdown

also.

• The unit shall be cleaned – and oiled to prevent corrosion – internally as well as

externally.

• All filter candles shall be cleaned and inspected to ensure that they are in good condition.

• Clean the flushing oil filter and replace the flushing filter insert.

• Also the trace heating (if installed) on lube oil and sludge lines would normally be

deactivated during a shutdown.

Lube oil storage and transfer system

All plants will have some sort of lube oil storage and transfer system, though the complexity

will vary depending on the size of the plant and the amount of lubricant that must be stored.

Smaller plants may have the oils stored in the drums it is delivered in, and the transfer

system may consist of a mobile transfer pump only. Such plants need only be concerned

about how the drums are stored (laying down on special stands or wooden pallets – not

directly on the ground – and protected against heat/strong sun).

The drums shall therefore preferably be stored indoors and in such way that the “bungs” (the

sealed openings) are covered by the contents of the drum to prevent that air is drawn into the

drum due to temperature induced volumetric changes.

However, these are normal procedures and the drums shall be stored in this manner also

when the plant is in full operation.

The mobile transfer pump need no special attention but should be stored indoors and be

protected against excessive heat and humidity.

Larger power plants may have quite complex and sophisticated lube oil storage and transfer

systems, including unloading system, transfer and storage system, automatic oil fillingsystem, etc. These systems must be studied and evaluated to provide the information that is

required when shutting down the plant. The following is some general guidelines provided to

help the planning process.


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Unloading system

The connections at the unloading point should be covered and preferably locked to prevent

that the inlet becomes contaminated.

NOTE!

It is recommended to put a numbered seal on the connection. It gives anindication of unauthorised entry if the seal were found to be broken. Use a seallog to record the seal number.

If possible, have the unloading system full of lube oil during the shutdown period as this can

act as corrosion protection.

Disconnect the power supply to the unloading pump unit. If the power supply is accessible,

that is, not installed in a lockable area it is recommended to also lock the breaker in OFF

position.

Storage system

1. Close and lock all outlet valves on the storage tanks (including new oil tanks,service/maintenance tanks and used lube oil tanks) to prevent spill if a valve downstream

is accidentally opened and also to prevent theft if the area where the new lube oil is

stored is left unguarded.

NOTE!

It is recommended to put a numbered seal on the valves in locked position. Use a“seal log” to record the seal number.


3. If possible, have the transfer system full of lube oil during the shutdown period as thiscan act as corrosion protection. 0.

Lube transfer system (oil filling)

NOTE!

The “lube transfer/oil filling system” is available in several different designs andfunctions from the fully automatic system to manually activated pumps and alsoto systems where the mobile transfer pump must be physically “hooked-up” to theengine that shall be filled with oil. It is therefore essential to develop the requiredshutdown methods based on the actual design selected for the plant.

1. Disconnect the control system (automatic lube oil filling system).

2. Close and lock the lube oil inlet valves at the engine oil sump.

3. If possible, have the oil filling system full of lube oil during the shutdown period as thiscan act as corrosion protection.

Any open connections (lube oil inlet-, or outlet connections) should be covered and

preferably locked to prevent that the connections becomes contaminated – either by accident

or by wilful vandalism.

NOTE!It is recommended to put a numbered seal on the connections. This gives anindication of unauthorised entry if the seal were found to be broken. Use a “seallog” to record the seal number.


27/108


4. Disconnect the power supply to the lube oil transfer/filling pump unit(s). If the powersupply is accessible, that is, not installed in a lockable area, it is recommended to also

lock the breaker in OFF position.

5. Disconnect the power supply to the control system. If the power supply is accessible,that is, not installed in a lockable area, it is recommended to also lock the breaker in

OFF position. 0.


Refer also to the supervision routines described for the genset in Section 2.3 Supervision of

genset during shutdown.

The supervision of the lube oil systems is fairly easy, and is similar to the supervision

routines for other systems at the plant.

Check:

• Contents of the new oil storage tanks

• Used lube oil tank and

• Maintenance tank if these contain oil.

If the tanks are equipped with a mechanical level indicator this should also be checked

regularly.

NOTE!

It is advisable to put a removable mark at the level where the system was shutdown. This is a simpler way to keep track of level changes than taking a readingand comparing this to reading made previously.

Drain out a sample to check if the tank contains water. Any water present should be drainedout as it might permit biological contamination to propagate in the tank.

Check:

• The temperatures in the tanks (record or make notes if found to be excessive in either

direction – too hot or too cold).

• All seals (if used) that they have remained intact.

• All pipes and flange connections for leakage.

• Pumps for leakage (flanges and shaft seal).


shafts, etc.)



28/108



The main and most important maintenance activities are described in Section 2.4

Maintenance of genset during shutdown.

The maintenance performed on the lube oil system during the shutdown period is mainly

performed to prevent corrosion damage, bearing damage and seizure of equipment, and issimilar to the maintenance activities required for other systems at the plant.









3. Check all valves in the system for signs of corrosion. Grease the valve stem and operatethe valve (open/close at least once) if possible without releasing liquid into other parts of

the system. This is particularly important for gate valves and globe valves. Butterfly

valves and ball valves may not benefit as much. 0.


Refer also to the re-activation procedures described for the genset in Section 2.5 Re-

activation of genset after shutdown.

NOTE!

Before re-activating the lube oil systems it is recommended to perform a thoroughinspection of the systems to detect any sign of leakage, corrosion or other signsof damages.

The system should already be filled with lubrication oil and – provided that it has beensupervised/maintained properly during the shutdown – it should be possible to re-activate

without any problems.

However, the following activities are recommended to ensure that the re-activation proceeds

smoothly.


29/108


Lube oil circulation system

The main activities to perform when re-activating the lube oil circulation system are

described in Section 2.5 Re-activation of genset after shutdown. Read the instructions as well

as the general information provided here.

NOTE!

If the genset is equipped with a lube oil treatment system, then this should beactivated before starting the procedures below.

Before starting the pre-lube pump, check:

• Lube oil filters’ condition and that no sludge has accumulated in the filter housing.

• Centrifugal filter (if installed) is clean and in fully operational condition.

• All valves are in the normal operating position according to the list of manual valves

(available in the operating instructions).

NOTE!

It the genset is equipped with an external circulation pump, the pump must bechecked to ensure that it is in fully operational condition.

• Vent the pump’s housing and the suction strainer.

! CAUTION!The pump should not be permitted to run dry, and it is necessary to ensure thatthe pump is filled with oil before starting it.

• Check that the feeder pump’s shaft rotates freely.

• Activate the power supply and “jog” the pump to ensure that it is operating properly. Set

the pump to “AUTO”

• When in operation, check the pump carefully to ensure that it is functioning properly (no

noise, vibrations, leaks or overheated bearings).

• Check the function of the alarm system.

Lube oil treatment system (separator unit)

NOTE!

If the separator has had the bowl removed for the shutdown, then it must becleaned and re-assembled before the treatment system is re-activated.

1. Activate the tank heating system (separator sludge tank)

2. Activate the trace heating (if installed) of the system and all units installed.


4. Vent the separator feeder pumps housing and the suction strainer.


6. Activate the power supply and start the separator unit according the instructions in theoperation manual.

7. Vent the separator oil heater, and activate the heater when filled with oil.


30/108


8. Check the separator carefully to ensure that it is operating properly (no noise, vibrations,leaks or overheated bearings).


Lube oil treatment system (automatic lube oil filtration unit)

The automatic lube oil filtration unit shall be re-activated according the Original Equipment

Manufacturer’s (OEM) instructions. The information below is given as guidance only.

1. Activate the trace heating (if installed) of the unit and associated piping.


3. With the pre-lube pump (or external circulation pump) in operation, vent the filterhousing (if necessary).

4. Activate the power supply and start the automatic filtration unit according theinstructions in the operation manual.

5. Check the automatic filtration carefully to ensure that it is operating properly (no noise,

vibrations or leaks).6. Check the function of the alarm system. 0.

Lube oil storage and transfer system

For smaller power plans without any elaborate storage and transfer system, there are no

activities necessary. The oil is probably stored in drums only.

However, for the larger plants the following information might be useful.

Unloading system

The unloading system needs to be re-activated first when new lube oil arrives at site.

1. Check that the unloading pump’s shaft rotates freely.2. If possible, vent the pump- and strainer housing.

! CAUTION!The pump should not be permitted to run dry, and if the pump has been drainedof oil during the shutdown period it would be beneficial if possible to have theunloading system filled with oil from the tanker truck before starting it.


4. Open valves according to the list of manual valves available in the operating

instructions.

5. Start the unloading according to the instructions in the operating manual.

6. Check the pump carefully to ensure that it is operating properly (no noise, leaks oroverheated bearings). 0.

Storage system

1. Drain out any water in the tanks (new oil tank, maintenance tank, used lube oil storage).



31/108


Lube transfer/oil-filling system

NOTE!

If the plant is equipped with an automatic lube oil filling system (providing enginewith oil as required and controlled by level switches/sensors in the oil sump) then

this system should be activated already when the gensets are prepared for start.


2. Vent the transfer/oil filling pumps housing and also the suction strainer.

3. Check that the transfer/oil filling pump’s shaft rotates freely.



6. Start the transfer/oil filling system according to the instructions in the operating manual.

7. Check the pump carefully to ensure that it is operating properly (no noise, leaks oroverheated bearings).

8. Check that the control system function properly (stopping the pump at high level andstarting it at low level). 0.

3.3 Compressed air systems

The compressed air system varies in complexity depending on the plant but in general it

consists of the following systems:

• Start air system

• Control/instrument air system

• Work air system

Before shutting down any of these systems, it is necessary to investigate the effect it would

have on the activities that have to be performed during the shutdown period, that is, are any

of these systems needed during the shutdown period. If needed, it should remain in

operation.


Start air system

The start air supply to the genset must be shutdown with the inlet valves closed and locked

as part of the genset shutdown procedure.

When all gensets are shut down, and there is no more need for start air, the system should be

de-activated as follows:

1. Drain the start air system between the receiver and the engines start air valve. Make surethat all condensate is removed from the system.

NOTE!

If the drain valve were left open it would be recommended to place a plastic cover

over the drain outlet from the valve. This will prevent humid air from entering thesystem, yet it would easily blow off if the system would become pressurised.

2. Close the outlet valve on the start air receiver.


32/108


WARNING!

If the receiver will be shut down fully charged, then it would be recommended toalso lock this valve (to prevent that it will be accidentally opened while other partsof the system may be under work).

3. Charge the receiver while draining out all condensate.

4. Shut down the compressor according to the instructions given in the operating manual.

5. Disconnect the power supply to the compressor unit(s). If the power supply isaccessible, that is, not installed in a lockable area, it is recommended to also lock the


6. Close the inlet valve to the start air receiver and open the drain valve in the line betweenthe start air compressor and the start air receiver. 0.

NOTE!

If this drain valve were left open it would be recommended to place a plasticcover over the drain outlet from the valve.

! CAUTION!The start air compressor unit can be of several designs; single unit, double unit,electrical drive only or with a combination electrical drive/diesel drive. It istherefore important that the original equipment manufacturer’s (OEM) instructionsregarding preservation for a short-term shutdown are followed.

Control/instrument air system

! CAUTION!It is essential that the control/instrument air system is carefully investigated toensure that it can be de-activated during the shutdown period. It can be used forsome essential services (safety, supervision, alarm, etc.) and can therefore haveto be in full operation during the shutdown period.

When all control/instrument air consumers are shut down, and there is no more need for

control/instrument air, the system should be de-activated as follows:

1. Drain the control/instrument system between the receiver and the consumers. Make surethat all condensate is removed from the system.

NOTE!

If the drain valve is left open it is recommended to place a plastic cover over thedrain outlet from the valve. It prevents humid air from entering the system, yet itwould easily blow off if the system would become pressurised.

2. Close the outlet valve on the compressed air receiver.



5. Shut down the air dryer according to the instructions given in the operating manual.


33/108




7. Close the inlet valve to the air receiver and open the drain valve in the line between thecompressor and the air receiver. 0.

NOTE!

If the drain valve is left open it is recommended to place a plastic cover over thedrain outlet from the valve.

! CAUTION!The control/instrument air compressor unit can be of several designs; single unit,double unit, with or without air dryer, etc. It is therefore important that the originalequipment manufacturer’s (OEM) instructions regarding preservation for a short-term shutdown are followed.

Work air system

! CAUTION!The work air system must be investigated to ensure that it can be de-activatedduring the shutdown period. It may be needed for some essential services(safety, supervision, alarm, etc.) and therefore has to be in full operation duringthe shutdown period.

However, the work air requirement during shutdown can be less than during

normal operation, and it can therefore be possible to buy (or rent) a smaller unitto supply the necessary work air during the shutdown of the plant.

When all work air consumers are shut down, and there is no more need for work air, the

system should be de-activated as follows:

1. Drain the work air system between the receiver and the consumers. Make sure that allcondensate is removed from the system.

NOTE!

If the drain valve is left open it is recommended to place a plastic cover over the

drain outlet from the valve. This will prevent humid air from entering the system,yet it would easily blow off if the system would become pressurised.

2. Close the outlet valve on the work air receiver.





6. Close the inlet valve to the air receiver and open the drain valve in the line between the

compressor and the air receiver.


34/108


NOTE!

If the drain valve is left open it is recommended to place a plastic cover over thedrain outlet from the valve.

7. Clean all filters in the work air system (workstations), and empty and clean alllubricators to prevent the oil from emulsification should humidity enter the system. 0.

! CAUTION!The work air compressor unit may not be equipped with any air receiver and willmaintain the pressure in the system by load modulation. The informationregarding the air receiver in the instructions above should then be ignored.


The supervision of the compressed air systems is fairly easy, and mainly consists of thefollowing.

Check:

• Pressure in the start air receiver, the control/instrument air receiver and the work air

receiver (if these are installed and kept charged during the shutdown period).

NOTE!

Rapidly falling pressure in the tanks indicate leakage, and this should beinvestigated and rectified.

• All (pressurised) pipes and flange connections for leakage.

• Compressor units according to the manufacturer’s instructions.

• Air dryer according to the manufacturer’s instructions.


shafts, etc.)



The maintenance performed on the compressed air system during the shutdown period ismainly performed to prevent corrosion damage, bearing damage and seizure of equipment,

and is similar to the maintenance activities required for other systems at the plant.









35/108



NOTE!

The compressors can be hard to turn by hand and it can be simpler, if power isavailable, to run the compressor for a while. This also applies to any diesel drivencompressor unit.

3. Ball valves are most commonly used in compressed air system and should not need any particular maintenance during a short-term shutdown. However, if globe valves (or

“needle” valves) are used, these may benefit from being operated once a week

(open/close at least once) if possible without releasing compressed air into other parts of

the system. Grease the valve stems at the same time. 0.


Start air system

The start air compressor unit shall be re-activated according the Original Equipment

Manufacturer’s (OEM) instructions. The information below is given as guidance only.

1. Open all shut-off valves in the line between the compressor and the start air receiver.

2. Check that the drain valves in the line between the compressor and the start air receiverare open

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