gas turbine start up
TRANSCRIPT
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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.