Duel Fuel System Description

7/27/2019 Duel Fuel System Description

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Dual Fuel System



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Revision History

Revision Date Content of Change DocumentPages total:

A 10-1-2003 Description edited and completed.Diagram HTCT 319 679-1, -2 replaced withHTCT 319 679-1A, -2A

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Contents

1 GENERAL DESCRIPTION........................................................................................... 5

1.1 Function ................................................................................................................ 5

1.2 Design ................................................................................................................... 5

1.3 Principle of Operation.......................................................................................... 6

1.3.1Operation on Gas............................................................................................. 6

1.3.2Operation on Oil ............................................................................................... 6

1.3.3Emergency Change-Over from Gas to Oil........................................................ 6

1.3.4Change-Over from Gas to Oil (manually initiated)............................................ 7

1.3.5Change-Over from Oil to Gas........................................................................... 8

1.4 Safety and Monitoring Equipment ...................................................................... 9

2 APPENDICES............................................................................................................. 12

2.1 Designation of Parts .......................................................................................... 12

Diagram.....................................................................................HTCT 319 670-1A, -2A

n

Additional Documents:

Fuel Gas System HTCT 690 550

Fuel Oil System HTCT 690 551

NOX-Water System HTCT 690 565



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1 GENERAL DESCRIPTION

1.1 Function

The dual fuel system supplies the EV-burners with the fuel required for

combustion (during normal operation: gas or liquid fuel; during changeover:

gas and liquid fuel), at the correct pressure, temperature and flow rate

corresponding to the required power output of the gas turboset.

The dual fuel system increases availability of the gas turboset since the

machine can be changed over from one type of fuel to the other, e.g., if there

is a malfunction in one fuel system or a shortage of fuel.

The changeover from fuel gas to fuel oil is possible in the whole range of pilotgas operation and is initiated manually.

If a changeover is initiated during premix operation first load has to be

reduced below the premix load point before the changeover program can be

started. If the changeover is initiated automatically due to low gas pressure

the load reduction is also initiated automatically.

As an option, automatic changeover from fuel gas to fuel oil is available.

A changeover from fuel oil to gas must be initiated manually.

1.2 DesignDiagram HTCT 319 670-1A, -2A shows the design in schematic form. The

main parts of the system are:

the fuel gas system MBP (refer to HTCT 690 550)

• the fuel oil system MBN (refer to HTCT 690 551)

• the NOX-water system MBN (refer to HTCT 690 565)

• components for fuel changeover.

FOnly sectors 1 and 18 are shown in details in diagram

HTCT 319 670-2A!



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1.3 Principle of Operation

1.3.1 Operation on GasTo operate on fuel gas, the push-button “Gas Operation ON” in the control

room is used to initiate the starting program for burning gas. (Refer to Fuel

Gas System, HTCT 690 550)

1.3.2 Operation on Oil

To operate on oil, the push-button “Oil Operation ON” in the control room is

used to initiate the starting program for burning oil. (Refer to Fuel Oil System,

HTCT 690 551 and NOX water System, HTCT 690 565)

1.3.3 Emergency Change-Over from Gas to Oil

Whenever the gas supply pressure before control valves MBP41 AA002,

MBP42 AA002 and MBP43 AA002 drops below a preset limit, an alarm is

initiated.

If the gas pressure drops further Fuel Gas Pressure Control is activated.

If automatic fuel changeover is activated and the pressure drops further to

Gas Pressure Change-Over Limit the fuel selection control initiates

automatically the change over from fuel gas to fuel oil and the Fuel Gas

Pressure Control is deactivated.

Control valves MBP41 AA002 and MBP42 AA002 start to close.

At premix load point control valve MBP43 AA002 starts to open.

When reaching premix begin load control valves MBP41 AA002 and MBP42

AA002 have completely closed.

After completion of changeover from premix to pilot operation, the deloading

process is interrupted and the power output remains constant.

Then the changeover from fuel gas to fuel oil is initiated which proceeds

automatically.

The start-up of fuel oil system MBN and NOX water system MBU are initiated.

Main shut-off valves MBN31 AA001 and MBU31 AA001 open. Oil and water

flows to pumps MBN32 AP001 and MBU32 AP001. When the pressures

reach the preset levels needed for pump operation, the fuel pump and the

water pump start operating.

Oil and water flows to trip valves MBN40 AA001 and MBU40 AA001. Once

the pressures reach the preset levels, pressure measurements MBN32

CP001 and CP002, MBU32 CP001 and CP002 enable continuation of fuel

changeover.

Drain valves MBN51 AA001 and AA002 close.



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Trip valve MBN40 AA001 opens. When the trip valve leaves the closed

position, the three flame monitors MBM11 CR001, CR002 and CR003 areunblocked for fuel oil operation (the flame monitors are activated for fuel gas

operation. They remain activated without interruption during fuel change

over).

Oil flows to control valve MBN41 AA001.

For quick deairation of the fuel oil control MBN41 vent valve MBN41 AA060

opens. Control valve MBN41 AA001 opens completely for a preset short time.

The fuel oil flows in the fuel oil control and presses the air through vent valve

MBN41 AA060 into the fuel oil return.

Then control valve MBN41 AA001 closes to minimum stroke (oil flow for main

ignition). The burner valves for fuel oil open. The oil for main ignition flows

through the EV-burners into EV-combustor, where it is atomized and ignited

by the gas flames.

Control valve MBP43 AA002 starts to close and control valve MBN41 AA001

continues to open simultaneously.

The fuel oil control valve and the fuel gas control valve are controlled in such

a way, that the sum of the two fuels supplied maintains constant power output

from the gas turboset throughout the change-over.

When a preset fuel oil flow is reached burner valves for NOX water of the

operating burners open, control valve MBU41 AA001 opens to the setminimal flow.

Then the oil and water is injected through the EV-burner lances into the

combustor. Water flow increases until the preset Ω (water to oil ratio) is

reached. Fuel and water flow increase and gas flow is reduced until gas

control valve MBP43 AA002 has completely closed.

Change-over is completed when all the fuel required for power output is

supplied by the fuel oil system and the supply of gas is completely shut off, i.

e., main shut-off valve MBP31 AA001, trip shut-off valve MBP40 AA001 and

control valves MBP41 AA002, MBP42 AA002 and MBP43 AA002 are closed.

Gas relief valves MBP31 AA002 and MBP51 AA001 are open.

After changeover has been completed control valves for oil and water

continue to open, power output increases until it reaches the level before

deloading was initiated.

Loading progresses the same way as during normal fuel oil operation.

1.3.4 Change-Over from Gas to Oil (manually initiated)

Changeover procedure is initiated manually and is possible throughout the

complete range of power output.



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• The operator sets the power output to the changeover level (only in the

load range of pilot gas operation). The gas turboset deloading proceedsaccording to the deloading gradient.

• When power output has dropped to the changeover level, the operator

initiates the changeover, which then proceeds automatically in exactly the

same way as the automatically initiated changeover.

• When changeover has been completed, the operator sets the power output

to the demanded level. The load then increases to the set level according to

the loading gradient.

1.3.5 Change-Over from Oil to Gas

The changeover procedure can only be initiated manually and is only possiblein the range above 30% of base load. It then proceeds like the changeover

from gas to fuel oil, but in reverse order.

• Control valves MBN41 AA001and MBU41 AA001 start to close and pilot

gas control valve MBP43 AA002 starts to open. The oil, water and gas control

valves are actuated in such a way as to maintain constant power output of the

gas turboset throughout the changeover sequence.

• When changeover has been completed, the operator sets the power output

to the demanded level. The load then increases to the set level according to

the loading gradient.

After the changeover from oil to gas has been completed, purging valves

MBU35 AA131 and MBU35 AA132 open according to the purging sequence.

Water flows through the oil supply lines and the oil lances and purges the fuel

oil from these lines into EV-combustor MBM10 thereby preventing a coking of

the burner lances.

Then fuel oil system and the water injection system are shut-off.



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1.4 Safety and Monitoring Equipment

MBM11 CR001, CR002 and CR003: Flame monitors

Description see: “Fuel Gas System” HTCT 690 550 or “Fuel Oil System”

HTCT 690 551.

MBM11 CT001 and CT002: Measurements of temperature

Description see: “Fuel Gas System” HTCT 690 550 or “Fuel Oil System”

HTCT 690 551.

MBN31 CP003: Measurement of pressure

The sensor monitors the pressure before fuel oil pump MBN32 AP001.

Should the pressure not have reached the required level for fuel oil operationan alarm is initiated in the control room. Further progress of the start-up

(changeover) program is prevented until the pressure has reached the

preset level.

Once the pressure reaches the preset level, the measurement enables

further progress of the changeover program.

MBN32 CP001 and CP002: Measurements of pressure

During fuel oil operation the measurements monitor the pressure after the fuel

pump and display it in the control room.

If the pressure in one of the measurements drops below a preset level an

alarm is initiated in the control room.

If the pressure in one of the measurements drops below the preset minimum

level a load shedding is initiated.

MBN41 CP001, CP004 and CP006: Measurements of pressure

Description see: “Fuel Oil System” HTCT 690 551

MBP01 CP001: Measurement of pressure

It monitors the pressure before main shut-off valve MBP31 AA001

- Start-up: It initiates an alarm and prevents further progress of thestart-up program until that pressure has reached the required minimum.

- Operation: If the pressure drops below a preset level an alarm is

initiated in the control room.

MBP40 CP001 and CP002: Measurements of pressure

The sensors monitor the pressure in the gas supply line after trip valve MBP40

AA001 and display it in the control room.



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If the pressure in one measurement drops below the preset limit an alarm is

initiated in the control room.If the pressure in one measurement drops below the preset minimum level a

load shedding is initiated.

MBP40 CP021: Measurement of differential pressure (Pressure transmitter)



Measurement MBP40 CP021 monitors the differential pressure after the control

valves between system MBP41 and MBP42.

Measurement MBP40 CP022 differential pressure after control valves between

system MBP42 and MBP43.Measurement MBP40 CP023 differential pressure after control valves between

system MBP41 and MBP43.

The measured values are transmitted to the control room. The differential

pressures are displayed in the control room.

The EGATROL uses the values also to calculate the fuel flows.




They monitor the differential pressures across control valves MBP41 AA002,

MBP42 AA002 and MBP43 AA002 and transmit the measured values to the

control room

The differential pressures are displayed in the control room.

The EGATROL uses the values to calculate the fuel flows.

If the differential pressure across one control valve drops below the preset

minimum level a load shedding of the gas turboset is initiated.

If either one of the calculated values or the measured value from MBP41

CP004 drops below a preset level an alarm is initiated.

When the load is removed to the preset level, changeover from gas to oil is

initiated automatically.

MBU31 CP003: Measurement of pressure

The sensor monitors the pressure before NOX water pump MBU32 AP001.

It initiates an alarm in the control room and prevents further progress of

the start-up (changeover) program for operation on fuel oil until that

pressure has reached the preset level.



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Once the pressure reaches the preset level, the measurement enables

further progress of the changeover program.MBU32 CP001 and CP002: Measurements of pressure

During fuel oil operation the measurements monitor the pressure after the

water pump and display it in the control room.

If the pressure in one of the measurements drops below a preset level, an

alarm is initiated in the control room.

If one of the measured pressures drops below the preset minimum level a

load shedding is initiated.

MBU40 CP001, MBU41 CP004 and CP006: Measurements of pressure

Description see: “NOX Water System” HTCT 690 565



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2 APPENDICES

2.1 Designation of PartsKKS-No. Designation

MBA30 Fuel/water drain

MBM10 EV-combustor

MBM11 EV-burners

MBM11 AA121 Non-return valves

to

MBM11 AA138 Non-return valves

MBM11 AV101 EV-burner

to

MBM11 AV118 EV-burnerMBM11 CR001 Flame monitor 1

MBM11 CR002 Flame monitor 2

MBM11 CR003 Flame monitor 3

MBM11 CT001 Measurement of temperature

MBM11 CT002 Measurement of temperature

MBN31 Fuel oil supply system

MBN31 AA001 Main shut-off valve, fuel oil

MBN31 AT001 Twin filter for fuel oil

MBN31 CP003 Pressure measurement before fuel pump

MBN31 DP002 Pressure limiting valve

MBN32 Liquid fuel system from fuel pump

MBN32 AA001 Minimum flow valve

MBN32 AP001 Fuel pump

MBN32 BP011 Orifice

MBN32 CP001 Pressure measurement after fuel pump

MBN32 CP002 Pressure measurement after fuel pump

MBN34 Fuel oil return system

MBN34 DP001 Pressure limiting valve

MBN40 Fuel oil system

MBN40 AA001 Trip shut-off valve

MBN41 Fuel oil control

MBN41 AA001 Control valve, fuel oil

MBN41 AA060 Vent valve, fuel oil

MBN41 AA101 Burner valve, fuel oil

MBN41 AA101A Solenoid valve to burner valve fuel oil

MBN41 AA001L Position burner valve oil closed (Limit switch "Closed")

to

MBN41 AA118 Burner valve, fuel oil



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MBN41 AA118A Solenoid valve to burner valve fuel oil

MBN41 AA118L Position burner valve oil closed (Limit switch "Closed")MBN41 AT001 Strainer

to

MBN41 AT018 Strainer

MBN41 CP001 Measurement of pressure before control valve

MBN41 CP004 Measurement of diff. pressure acrosscontrol valve

MBN41 CP006 Measurement of pressure after control valve

MBN51 Fuel oil drain

MBN51 AA001 Drain valve, fuel oil

MBN51 AA002 Drain valve, fuel oil

MBP01 Fuel gas supply before main shut-off valve EVMBP01 CP001 Measurement of pressure

MBP31 Fuel gas supply before trip valve

MBP31 AA001 Shut-off valve, main gas

MBP31 AA002 Relief valve

MBP31 AT001 Dirt trap

MBP40 Fuel gas system

MBP40 AA001 Trip shut-off valve

MBP40 CP001 Measurement of pressure before control valve

MBP40 CP002 Measurement of pressure before control valve

MBP40 CP021 Measurement of differential pressureMBP40 CP022 Measurement of differential pressure

MBP40 CP023 Measurement of differential pressure

MBP41 Fuel gas control (premix 2/3)

MBP41 AA002 Control valve

MBP41 CP011 Measurement of differential pressure, control valve

MBP42 Fuel gas control (premix 1/3)

MBP42 AA002 Control valve

MBP42 CP011 Measurement of differential pressure, control valve

MBP43 Fuel gas control, (pilot)

MBP43 AA002 Control valveMBP43 CP011 Measurement of differential pressure, control valve

MBP51 Fuel gas relief (EV-combustor)

MBP51 AA001 Gas relief valve

MBQ30 Ignition fuel system

MBU31 NOX -water system

MBU31 AA001 Main shut-off valve, NOX -water

MBU31 AT001 Filter, NOX -water

MBU31 CP003 Measurement of pressure before water pump



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MBU31 DP002 Pressure reducing valve

MBU32 NOX -water system from water pump

MBU32 AA001 Minimum flow valveMBU32 AP001 NOX -water pump

MBU32 BP011 Orifice

MBU32 CP001 Measurement of NOX -water pressure

MBU32 CP002 Measurement of NOX -water pressure

MBU34 NOX -water return system

MBU34 AA002 None-return valve

MBU34 DP001 Pressure reducing valve

MBU35 NOX -water control

MBU35 BP012 Orifice

MBU40 NOX -water systemMBU40 AA001 Trip shut-off valve

MBU40 CP001 Measurement of NOX -water pressureMBU41 NOX -water control

MBU41 AA001 Control valve

MBU41 AA101 Burner valve, NOX -water

MBU41 AA101 A Solenoid valve to burner valve, NOX -water

MBU41 AA101 C Non-return valve

MBU41 AA101 D Non-return valve to control airMBU41 AA101 L Position burner valve closed (Limit switch "Closed")

toMBU41 AA118 Burner valve, NOX -water

MBU41 AA118 A Solenoid valve to burner valve

MBU41 AA118 C Non-return valve

MBU41 AA118 D Non-return valve to control airMBU41 AA118 L Position burner valve oil closed (Limit switch "Closed")

MBU41 AT001 Strainer

to

MBU41 AT018 Strainer

MBU41 CP001 Measurement of pressure before control valve

MBU41 CP004 Measurement of diff. pressure across control valveMBU41 CP006 Measurement of pressure after control valve

MBU51 AA001 NOX – water drain valve

MBX36 Control air

MBX37 Control air

Duel Fuel System Description

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