Gas Turbine Start Up

8/12/2019 Gas Turbine Start Up

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GAS TURBINE

Petronas Gas

Berhad

GPP 5&6 18 December 2005


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History of Gas Turbine

1. Gas turbine cycle is also known as BraytonCycleGeoge Brayton 1870.

2. The first gas turbine was constructed by BrownBoveri having a capacity of 4MW beeninstalled at Neuchatel, Switzerland atefficiency of 17%.


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GAS-TURBINE THEORY

A simple gas turbine is comprised of three main sect ion s

a compressor, a combustor, and a turbine. The gas-

turbine operates on the principle of the Brayton cycle,

where compressed air is mixed with fuel, andburnedunder constant pressure conditions. The resulting hot

gas is allowed to expand through a turbine to perform

work. approximately two / thirds of this work is spent

compressing the air, the rest is available for other workie.( mechanical drive, electrical generation)


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Brayton Cycle


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Types of Gas Turbines

There are two basic typesof gas turbines

Aero derivativeunits are aircraft jet engines

modified to drive electrical generators

Industrial gasturbinesunits robust

construction, are suitable for base load

operation


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Aero derivative (from jet engine)


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Industrial Gas Turbines


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Gas Turbine with Regeneration

One variation of this basic cycle is the addition of a

regenerator. A gas-turbine with a regenerator

(heat exchanger) recaptures some of the energyin theexhaust gas,pre-heating the air entering

the combustor. This cycle is typically used on

low pressure ratio turbines.


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Gas Turbine with Regeneration
http://nyethermodynamics.com/primer/turbine2.gif


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HORSE POWER

A unit of power equals to 33,000 ft-lb/minor

550 ft-lb/secor 2,545 Btu/hr.

1hp = 746 watts


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COMPRESSORSURGE

Pulsating of compressor discharge pressure

due to chokage as a result of too much of air to

be handled


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Blow Off Valve

Prevention against compressor surgeduring start up

/ shut down and acceleration (The valve reduce back

pressure by venting air to atm through BOV line to

exhaust duct) and compressor began surging whenfront stages of compressor would be highly loaded

(mid Span)


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Type of Gas Turbine

There are two type of gas turbine

Single Shaft

Split Shaft


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Single Shaft Gas Turbine

Inlet Air

Combustion Chamber

Exhaust

WorkTurbine

Compressor

Fuel


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Single Shaft Gas Turbine

The single shaft gas turbine was develop

primarily for the electric power industry

and uses a compressor and a powerturbine integrated on a common shaft. As

the unit is used continuously at single

rotational speed.


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Split Shaft Gas Turbine

Inlet Air

Combustion Chamber

Exhaust

Work

Power Turbine

Compressor

Fuel

High Power Turbine


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Split Shaft Gas Turbine

The split shaft gas turbine was develop

primarily for mechanical drive application

like pump and compressor, where theoutput power and speed might be

expected to be variable.


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Main component

1. Gas Generator (GG) which consist of

Compressor / air compressor

Combustion chamber

High Power Turbine (HPT)

3. Power Turbine (PT)

Casing for compressor and turbine

Accessory (L.O, Sealing & etc)


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Main component


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Gas Generator

The gas generator consists of an axial flow

compressor, combustion chambers and two-

stage turbine. When in operation, air enters the gas generator

inlet, passes through the inlet duct and enters

the compressor, where the air is compressed to

an approximate ratio of 18/1


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The angles of the inlet guide vanesand first six

stages of compressor vanesare varied as a

function of gas generator speed and compressorinlet temperature.

Changing the vane positions gives efficientoperation of the compressor over a broad speedrange, while maintaining an effective stallmargin. The vane positions are controlled by aspeed sensor and servo valve.


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Air leaving the compressor, enters the

combustionsection. Here the temperature

of some air is raised as a result of fullcombustion, which takes place inside the

combustion liner. The remaining air

entering the combustor section cools thecombustion section,


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Leaving the combustor, hot gas passes

through the two-stage high pressure

turbine, where energy is extracted fromthe gas to turn the axial compressor.

Turbine blade and vane cooling air mixes

with the mainstream gas it passes throughthe turbine.


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Leaving the gas generator, the hot gas

drives the free wheeling GT-61 power

turbine. The power turbine provides themechanical power output for the driven

equipment.


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Compressor

The compressor is driven by the

turbine via a connecting shaft and has

the job of drawing external air into

the engine,pressurizing it, and

passing italong to the combustionchamber.


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Compressor

stator

rotor

shaft

Air flow


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Compressor

Axial compressor type ismostly used due toitshigh output and

efficiency. (Usuallyvariable blade couldproduce 16bar)

Compressor design beenimprove by

Improving blade profile

Improving blade sealing

Improving blade material towithstand high

temperature.


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1. Centrifugal compressor This compressor uses a spinning impeller to draw in

intake air and accelerates it outward by means ofcentrifugal force into a diffuser.

It is used in small gas turbinesand is best suited

for low pressure ratioswhere the overall engine

diameter is not important.


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2. Axial flow compressor

Consists of rotating blades andstationary vanes. Air is

compressed as it flows axiallyalong the shaft. This allowsgreater efficiencyand higher pressure ratiosby multi-

stage construction. A stage of compression consists of one

row of rotating blades followed by a row of stationary

vanes. This is the most common type of compressor used inmarine gas turbine engines.


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Variable stator


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Air flow

Air for gas generator combustion flows

through air inlet filter, silencer and

plenum before entering the gasgenerator


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Fuel sprayedfrom the fuel injector nozzles,

mixes with high-pressure airentering the

combustion chamber through its perforationsfrom the compressor.

This mixture of compressed air and fuel then

burns at temperatures approaching 2000

o

C, inorder to maximize the heat energy obtained


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The combustion processis first initiatedby

igniter plugs, which are then isolated after

ignition has been accomplished.The combustion of the fuel and air mixture is

continuous and remains so until the fuel

supply is removed.


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Zone in which fuel is evaporated

and mixed with air

Zone in which fuel is ignited

And burnt Heat is generated

Cooling air


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combustor

Combustion chamber configuration

1.Single Silo

compressor is mixed with fuel and ignited in thischamber

3.Twin silo (each consist of multiple burners)

4.Can annular (ez maintenance & betterbalance)

5.Annular ring (popular for >200MW)


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Silo combustor

Silo combustion chamber in

its simplest form

consist of single burner or

multiple burner.Compressed air from the

The hot gas is then lead to

the turbine section


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Silo combustor

Disadvantageinfluence the size of the

turbine house.

Advantagefurnace inspection can be

done easilybecause of it big

size.


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Silo combustor


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Can Annular combustor

1. Individual burner cansare mounted around the

periphery of the engine. Each can is an

individual combustorand liner receiving its own

fuel supply.

Advantage: Easy replacement

Disadvantages - Inefficient, structurally weaker


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Annular combustor

One large combustor within the engine case.

Multiple fuel nozzles form a solid "ring of fire".

This type is used on the LM2500

Advantage

Most efficient, strongest, frame member of engine

Disadvantage

A repair or replacement requires complete enginedisassembly.


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Annular combustor


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High Power Turbine & Power


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High Power Turbine & Power

Turbine

Function

To convert high pressureand temperature

combustion gasesinto mechanical energyanddrive the compressor and generator.

turbine blades

convertsthe kinetic energyinto mechanical

energy


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HPT cooling


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Cooling HPT


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GG lube oil

Synthetic oilis used for the gas generator.

The console is mounted outside of the

turbine enclosure.


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Hydraulic oilafter filtration is routed to the

fuel metering valveactuator. Hydraulic oil

exiting the fuel metering valve actuator isreturned to the reservoir.


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Lube oilafter filtration is routed to theaccessory gearboxand bearing sumps.The lube oil is removed from theaccessory gearbox and bearing sumps byscavenge pumpP5-0502. The oil passesthrough filter S5-0506 which has a

pressure 505-PTD-1171 set to alarm at 30psig(207 kPa G) increasing on gauge505-PDG-1171.


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Magnetic chip detectorsare installed inthe drain linesfrom the accessory gearboxand each gas generator bearing sumpahead of the scavenging pumps. Anadditional magnetic chip detector isinstalled in the common drain header.

Metal carried by the drain oil willaccumulate on the detectors and signal analarm.


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Scavenge oilafter filtration flows to Cooler

E5-0502. A temperature valve 505-TCV-

1173regulates oil flow through or aroundthe cooler to maintain oil temperature at

60C.


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Air oil separator


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GG lube oil sump


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GG lube oil

FMV

Hydraulic oil filter

Hydraulic

Oil pump

Lube oil

pumpLube oil

Filter

Acc Gearbox

Lube Oil Sump

Scavenge oil pump

Scavenge oil Filter

Scavengeoilcoole

r

Gas Generator

7bar

36bar


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Power Turbine and Compressor Lube Oil

Mineral oilis used for the power turbineandcompressor lubrication. The console ismounted outside of the turbine enclosure.

Two pumpsare used for normal operation.

One pumpis driven by an electric motorandis used for start-upand standby. Theremaining pumpis drivenfrom the powerturbine accessory gearboxand supplies all of

the lube oil to the power turbineandcompressoronce the unit is in operation.


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Oil from the pumps flows to a separately

mounted fin fan cooler, E5-0506.

Temperature control valve 505-TCV-1108regulates oil flow through or around the

cooler to maintain oil temperature at 49C.


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Lube oilfrom the power turbine and compressor

bearings is returned to the reservoir.

A third oil pump, P5-0510 (Post Pump) isincluded in the lube oil console to provide

cooling oilto the power turbine after shutdown.

Unit control panel logicwill start pump P5-0510

after main unit shutdown has commenced.


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Lube Oil System (PT)

compressorGas Turbine

Filter

Aux LO Pump

Main PumpLO Reservoir

Cooler

Check valve

Emergency pump

Safety precautions


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y p

The following safety precautions must be

observed when adding lubricant (top up):

1.Avoid touching moving partsof the machine

2. Keep loose clothingwell away from moving

parts3.Avoid spilling lubricantonto hot surface

4. Clear up spillage immediately

5. Do not remove safety protectionfrom the machine

A good quality of lube oil


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A good quality of lube oil

Continuous checkof physical oil

characteristicsduring operation will predict

warrant of machinery life spent,

maintenance costand time saving.

The oil shall be oxidation, foam inhibited

and have good demulsibility for rapid

separation of water.


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Lube oil filter S5-0510A/B

hydraulic filters S5-0508A/B

scavenge oil filter S5-0506 PDI alarm at 30 psig

Operating precautions


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p g p

1. Avoid mixing different grades of oil

2. Avoid mixing different gradesof grease

3. Avoid mixing with water or other liquids

4. Avoid contaminationwith dust or dirt

5. Check that oil cansare free of all foreign

materials before filling

6. Avoid overfilling equipment

R ti Ch k


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Routine Checks1. During the shift, routine checks must be carried out

on a regular basis.2. The operator must carry out routine checks

immediately upon taking over the shiftto ascertainthe operating conditions of the unit and/orequipment.

3. Just prior to the end of the shift, the operator mustagain check the unit and/or equipment to ensurethathis handoverto the next operator is accurateandgives a true reflectionof the situation at that time.

4. Operating troublesthat may have been experienced

on the unit and/or equipment should berecorded inthe log bookand verbally


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The following check shall be carried out.

1. Check oil level.

2. Check oil temperature

3. Check oil pressure

4. Check and drain water.(Investigate

reason for water in the bearing.).

5. Take samplesfor laboratory analysiswhen requested


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Fuel and Start Gas

With control panel switchesin proper positionfora unit start, the logic circuits cause the followingevents to occur.


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Once purge cycle is complete, upstream

fuel gas valve(505-XCV-1181) is

energised to open. Vent valve(505-XCV-1183) is energised closedand the igniters

are switched on. Starting gasflow control

valve (505-PCV-1192) is ramped fully

opento bring starterup to high speedto

crankthe gas generator for startup.


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Fuel gas block valve (505-XCV-1184) is

energised open. Fuel is ignitedin the

combustion chambers of the gas generator and

speed ramps up to idle.

Once at idle the ignitersare switched off.

Starting gas flow control valve (505-PCV-1192)

is de-energised closed. Starting gas upstreamshutoff valve (505-XCV-1191) is de-energised

closedand the starter is shutdown.


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PT

1182

gas

manifold

XV

1183

XV

1181

XV

1184

VENT

TO SAFE

LOCATION

HP FUEL GAS

FMV

LM2500

GAS GENERATOR

ACC

GEARBOX

XV

1191

PV

11

92

STARTER GAS

STARTER

EXHAUST

POWER TURBINE


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Enclosure ventilation system

The enclosure surrounding the gas generatorand power turbine is provided with a ventilationsystem.

Air is pulled from the inlet air filter through asilencer by an electric driven fan

Three fansare used for the ventilation system.

Two fansare to be used during normaloperationand the third fanis for emergencyuse.


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The differential pressure within the enclosure is

monitored by a differential pressure switch 505-

PDS-1207

alarm and start the emergency ventilation fan

at 2.54 mm H2O decreasing

shutdown after 60 second delay if the

differential pressure does not increase abovethe alarm setting


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Fire and Gas Suppression Systems

Gas detectors505-AE-1211, 1212 and1213 are located in the intake plenum.

Gas detectors505-AE-1214, 1215 and1216 are located in the turbine enclosure

The gas sensors monitor gas levels withinthe plenum and enclosure. An alarmis

sounded if gas levels reach 20%.Shutdownoccurs if gas levels reach 60%.


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All access doorsto the air filter enclosure, intake

plenumand turbine enclosure are fitted with limit

switches which will sound an alarmif any door is

left open.

Fire detectorsare placed in the turbine

enclosure. The fire detectors are of the optical

type, and response to ultravioletand infraredradiationwhich is emitted by flame. The

detectors have a 120 field of view.


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When the detector senses UV or IR radiation, it signalsthe control panel module. The module issues signals totrigger release of CO2, and closesthe fire damper doorsto isolatethe fire in the enclosure. Two dump nozzles

559 and 560 are provided. The 559 nozzlesdump theCO2 into the enclosure at a fast rate. The 560 nozzledumps the CO2 at a slow rate. The CO2 bottles arestored in a cabinet which is adjacent to the unit. TwoCO2 tanksare provided for the main system (fast dump)and one CO2 tankis provided for the extended system(slow dump).A duplicate set of reserve tanks are alsoincluded in the system.


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WARNING

PERSONNEL SHOULD NOT BE EXPOSED TO

HIGH CONCENTRATIONS OF FOR

PROLONGED PERIODS TO CO2

DISCHARGE.

CO2MAY CAUSE SUFFOCATION AND

REDUCED VISIBILITY DURING AND AFTER ADISCHARGE PERIOD.


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Gas DetectorFire Detector (Optical)

FastDis

charge

SlowD

ischarge

Alarm 20%S/Down 60%

Response to ultraviolet and

infrared

Gas Turbine Enclosure

CO

2

CO

2

Temperature

Alarm 71deg CS/down 80deg C


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Periodic Maintenance

Every 4000Running hours

detergent wash with boroscope

25,000Running hours

Replacement of the Hot Section

Note; Depend on vender recommendation


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Water wash system

A.Purpose: Used to remove dirt and salt buildup on the

compressor blades.

B.Components: Consists of a 40 gallon tank and permanentlyinstalled piping to direct water wash solution into the inlet of the

compressor.

C.Procedure: Compressor must be washed to maintainefficiency and prevent compressor stalls.


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EXHAUST SYSTEM

Function:- Convey hot exhaust gases to eitheratmosphere or waste heat boiler

- exhaust casing-provides exhaust gases flow path

- exhaust ducting and silencer

- routes the exhaust gases to chimney or waste

heat boiler with a reduction in noise


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UNIT START-UP

Types of start-up

1. Start-up after maintenance.

2. Start-up after temporary shut-down. 3. Start-up after emergency shut-down.


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Start-up after Maintenance

Summary

Following a planned shutdown for

maintenance and inspection, the equipment

are handed back to operations department for

start up.

1. Pressure testsmust be made to ensure that all

disturbed flanges, valves and pipe work are leakfree


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2. The whole system must be thoroughly

purged of air by using nitrogen

3.AII accessoriesand equipmentrelated to the

operation of the main equipment must be

checked out correctly.

4. Check that all the platforms and immediate

external areasare clean and unwantedmaterial removed.


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CAUTION

WATER WASH VALVE IS OPENED ONLY

WHEN USING A WATER WASH CART.

OPEN EXHAUST CASING DRAIN VALVE

AFTER WATER WASH CART HAS BEEN

USED TO CLEAN THE UNIT OR TO REMOVE

LIQUIDWHICH HAS ACCUMULATED DURINGUNIT OPERATION.


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Gas Generator Lube Oil System

The pressureand temperature checkscan

only be made afterthe gas generatoris inoperation.


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Normal Start Sequence

A Normal Start Sequence can only be

initiated locally from the Local Control

Panel (LCP). When themodeselect switch on the LCP

is in Local, a Normal Start is initiated by

depressing the Start push button (PB-

1314) on the face of the LCP.

"Permissive To Start "


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Permissive To Start.

Gas Generator Oil Reservoir Level is OK

Power Turbine / Compressor Oil Reservoir Level is OK

Fuel Metering Valve is at Minimum Position (ZS-1186)

Fuel Shutoff Valves are closed

Start Gas Shutoff Vent Valves are closed (ZSC-1191)

AC Power "OK"

Vibration Monitor is "OK"

Turbine Enclosure Doors are closed

Unit Process Valves are in Shutdown (Prestart) Position


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Gas Generator Coastdown Timer Time out

Gas Generator Speed (N1) Ramp is at Minimum

Power Turbine Speed (N2) Ramp is at Minimum

LCP Run Local Mode is Selected (SS-1402)

All Fire and Gas System Alarms are Cleared

All Trip to Idle/Recycle Alarms are Cleared

Unit Shutdown is Cleared Buffer Gas Supply is greater than the Low Alarm

Fuel Control Summary Shutdown is Cleared


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NOTE

If the Permissive To Start pilot light is not

illuminated on the face of the LCP, select the

Start Permissive Screenon the Operator

Interface CRT the status for each of the above

conditions will be displayed.

The corrective actionfor each point should betaken in order to achieve a Unit Start

Permissive.


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Auxiliary Sequences

Stand-by Lube Oil Pump Test

Power Turbine/Compressor Lube Oil Pressure

Lube Oil Pump Sequence Enclosure fan Sequence

Seal Gas System

After the Auxiliary Sequence has been

completed, the Purge and Pressurising

Sequence for the Compressor will be initiate


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Pressurising Sequence

The Suction Bypass Valve (505-XV-0102) is

opened.

When the Differential Pressure across the

Suction Valve (505-XV-0101) is reduced to less

than 1.0 Bar the Suction Valve (505-XV-0101)

will open

After the Suction Valve is fully open, the SuctionBypass Valve (505-XV-0102) closes and the

Discharge Valve (505-XV-0103) will open


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Gas Turbine Start Sequence

The Gas Starter Control and ShutoffSolenoids 505-XY-1192 and 505-XY-1191are energised

The Primary Fuel Gas Shutoff Solenoid(505-XY-1181) is energised to open

The Starter Speed Control Output will be

ramped up until the Gas Generator Speed(N1) has achieved 1250 RPM


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If the Gas Generator fails to reach 1200 RPM withinthirty (30) seconds, a Fail To Crank Shutdown will beinitiated; thus the Unit Start/Run Sequence will beaborted.

GG Speed (N1) will be controlled between 1250 and1350 RPM to purge the Plenum, GG, PT/Exhaust Ductand the GG Purge Timer (TM-08)will begin to time out.

When the GG Purge Timer has timed out, the Starter

Speed Control Card High Speed command will beenabled and the Starter Speed Control Output will rampup to maximum.


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The Gas Generator will begin to accelerate. and. The

Ignitors (A or B) are alternated on successive starts of

the Gas Generator.

The Fuel Gas Vent solenoid (XY-1183) will be energised

to close.

The Ignitor Relay (A or B) (IGN-1261 or 1262) is

energised The Fuel Gas Secondary Shutoff Valve Solenoid (505-

XY-1184) is energised to open 505-XV-1184


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Light Off (T5.4 greater than 204C) must

be verified within 10 seconds after the

Secondary Shutoff is opened or a "Fail toLight Off Shutdown " is initiated. This will

then initiate a High Speed Purge of the

Gas Generator at greater than 2000 RPM

to rid it of any residual fuel.


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Once Light Off has been verified, the Gas

Generator will continue to accelerate until the

GG Speed (N1 ) has achieved 4500 RPM. When

the GG Speed (N1 ) is greater than 4500 RPM,the Starter Control Signal is disabled and both

the Gas Starter Supply and Shutoff Solenoids

are de-energised. Simultaneously, the Ignition is

also disabled. The Gas Generator continues

accelerating to Idle.


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Once the Gas Generator has reached Idle

Speed (5000 RPM), the Unit Warmup Timerwill

begin to time out. When the warmup Timer has

time out, the Unit is ready to load.

When the Unit Load Sequence is initiated, the

GG will accelerate until the Power Turbine

minimum speed (3250 RPM) is achieved. TheUnit will now be operated in Power Turbine

Speed Control Mode.

Normal operation & routineh k


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checks

During the shift, routine checksmust be carried out on a

regular basis.

The operator must carry out routine checks immediately

upon taking over the shift to ascertain the operatingconditions of the unit and/or equipment.

Just prior to the end of the shift, the operator must again

check the unit and/or equipment to ensure that his

handover to the next operator is accurate and gives atrue reflection of the situation at that time.


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Operating troubles that may have been

experienced on the unit and/or equipment

should be recorded in the log book andverbally communicated to the incoming

operator.


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Operating aspects to be monitored in order tokeep the performance of the unit under controland to identify proper corrective actions are:

Compressor and Turbine vibrations Compressor and Turbine axial displacement

Temperature and pressure of the lube oil systems.

Differential pressure across the Lube Oil Filters.

Differential pressure across the Hydraulic Oil Filters.

Status of the Lube Oil Stand-by Pumps. Differential pressure across Seal Gas Filters.

Differential pressure across Nitrogen Buffer Gas Filters.

Differential pressure across Instrumental air Filters.

Gas Generator speed.

Power Turbine/Compressor speed.

ypes o s ut own


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1. Shut down for maintenance

2. Temporary shut-down.3. Emergency shut-down.

Scheduled shut-down


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Scheduled shut-downs occur at infrequentintervals and are carefully planned. This

enables preventive maintenance workto be

carried out e.g. internal inspection of an

equipment. All maintenance work which cannot be

handled whilst the Equipment is in operation

is carried out at this time. A Previously

prepared shut-down procedure and work listmust be strictly adhered to. This will ensure a

safe, controlled shut-down and a minimum

loss of time in completing maintenance work.

perat ng precaut ons


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Close co-ordination between the Panel

Operator and Field Operator is essential forgood control.

Safe operating proceduresand safety

regulations must be followed at all times. Coordinate with other Units and warn the

other departments, especially the Fire

Department.

emporary s ut own


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A temporary shut-down is unscheduledand

may only last for a few hours. The shut-downfollows the same procedure as for ascheduled shut-down except that thepressure should be maintained ready for

immediate start up. A temporary shut-down is usually due to

operational requirements, or, a unit upsetofshort duration. Every effort must be made to

return to normal operations as soon aspossible.

Emergency shut-down


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An emergency shut-down can be caused byequipment failuresrelated to the plantoperation or utility failures, e.g. loss ofinstrument air.

In the event of an emergency shut-downbeing necessary the unit must be taken out ofservice as quickly and safely as possible.

The prevailing conditions at the time must betaken into consideration when shutting downthe unit.


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WARNING

Safety of personnel and the prevention of

damage to equipment are the primaryconsiderations. All operations personnel

must be thoroughly conversant with the

procedures to be taken for an emergency

shut-down.


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The exact procedure to follow must be

decided in the light of individual

circumstances at the time. Frequentchecking of equipment can normally give

adequate warning of impending trouble

and allow a normal shut-down to be

effected.


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A thorough knowledge of all the

equipment related to unit operation is

essential.

The main causesof unit emergencies are:

power failure, instrument air failure, fuel

gas failure.


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The following conditions will initiate a VentedShutdown: CO2 Release Shutdown

Common Fire Shutdown Inlet Plenum Gas Shutdown

Turbine Enclosure Gas Shutdown

Compressor Vibrations Shutdown

Compressor Thrust Shutdown Gas Seal Vent Leakage Primary High Shutdown or

Signal Fail


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PT/Compressor Lube Oil Supply Pressure

Low Shutdown or Signal Fail

Compressor Rupture Disc Failure Shutdown

Process ShutdownVented

Unit ESD

2 of 3 CPUs Failure Shutdown

Engine troubleshooting


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Engine troubleshooting

Troubleshooting is a systematic analysis

of symptoms that indicate equipment

malfunction. These symptoms usually

appear as deviations from normal values

of observed equipment parameters.


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Before concluding that an engine fault

does exist, the troubleshooter must assure

that his knowledge of suspected trouble

area is adequate, that the instruments

used are calibrated and working properly,

and that they have been accurately read

and interpreted.

NOTE


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NOTE

If troubleshooting procedures do not

isolate and eliminate the fault, secure

assistance from vendor service

representative through your customer

service manager.

GG Fails to reach maximummotoring speed


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motoring speed

If engine is hot, allow it to cool for 30minutesand then attempt motoring.

Check starter supply pressure. If pressure is

below minimum limit, check pressure source. Check instrumentation. Replace indicator if

defective.

Replace starter.if the rotation is still low,perform

borescope inspection of compressor and HPT.Check scavenge oil screens for sump problems.


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CAUTION


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CAUTION

ALWAYS PURGE FUEL FROM GAS

GENERATOR BY MOTORING THE GAS

GENERATOR AFTER ANY FALSE

START

WARNING


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WARNING

NO FUEL AIR MIXTURE MAY BE

PRESENT DURING THIS TEST.HIGH

VOLTAGE EXISTS AT THE IGNITERS,

THEY MUST NOT BE TOUCHED WHILE

ENERGIZED.

High Vibration in Gas Generator


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High Vibration in Gas Generator

Check that vibration instrument and its wiring

are operating properly

Check that vibration pickup is securely mounted.

Inspect oil scavenge and magnetic plugs in lube

scavenge pump.

Water wash compressor if inspection reveals

dirty blades and vanes.

High Vibration in Power Turbine


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High Vibration in Power Turbine

Check that vibration instrument and its

wiring are operating properly

Check that vibration pickup is securelymounted.

Inspect oil scavenge and magnetic plugs

in lube scavenge pump.

Low Lube Oil Pressure


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Low Lube Oil Pressure

Oil pressure is a function of gas generator

speed and supply temperature.

If oil supply pressure is low,check supplyoil filters for cleanliness and supply line for

leaks. If low pressure persists, replace

lube/scavenge pump.

Documents

Gas Turbine Start Up