17. STARTUP STEPS
Purging
Warming up time
Auxiliary lube/hydraulic oil pump and Ratchet motor start, Jaw
clutch will engage, Diesel engine start
START
(14HR(0% SPEED)
CRANKING
14HM(20% SPEED)
FIRE
(UPTO 50% SPEED)
At 60% speed Diesel engine disengage and shutdown
ACCELERATE
14HA(50% SPEED)
At 95% speed aux lube/hydraulic oil pump stop, bleed valves
closes
FSNL
14HS(95% SPEED)
18. TRIPPING CAUSES
High Inlet Filter ∆P
Low Lube Oil Pressure
Low Trip Oil Pressure
High Exhaust Pressure
High Lube Oil Temperature
High Exhaust Temperature
High Temperature Spread
Loss Of Flame
Over Speed Trip
High Vibration
Diverter/Guillotine Damper Closed
CO2 Released
Notas do Editor
A gas turbine also known as combustion turbine which produces mechanical energy by the kinetic energy of combustion gases.
The Utilities Unit has two General Electric model PG-5371 single shaft gas turbine. Each gas turbine is used to drive 36,600 KVA generator for Plant Electric Energy requirement.
The MS5001 gas turbine assembly consists of following major sections :
The MS5001 gas turbine assembly consists of following major sections :
The accessory section contains mechanical and electrical equipment necessary for starting and operating the gas turbine.
Different type of starting means are used for gas turbine starting like steam turbine, electric motor and internal combustion engine, Here we are using Diesel engine as starting means because this has advantages for Black Start.
A torque converter is generally a type of hydrodynamic fluid coupling that is used to transfer rotating power from a prime mover to a rotating driven load.
Lube oil used is Tellus-32.
Gas turbine performance and reliability are function of the quality and cleanliness of the inlet air entering the turbine.
The air inlet section consist of filter compartment containing self cleaning filters, which are used to remove abrasive particulate matter present in entering air. This filtered air sound is reduced with the help of Silencing Baffles & Include Trash Screen to prevent any dislodged material to enter into compressor section from here directed to inlet guide vanes through air inlet plenum.
Rack & Pinions mechanism has been used to operate the IGVs.
A hydraulic cylinder, mounted on a base cross member, actuates the inlet guide vanes through a large ring gear and multiple small pinion gears. The Min & Max opening is 42-84 Degree
Its Functionality is to …
Permit fast & Smooth Acceleration without Compressor Surge, Start up / Shut Down Pulsation Protection ,Exhaust Temp Control on CC on/off
Reverse Pulse type self cleaning system of 240 filters
Cleaning Pulsation start at 4 in H2O & continue till 2 in H2O
17th stage air After cooling in APU is used for Pulsation
Compressor section consists of 17 stage axial flow compressor. In rotor blades velocity of air increases and in stator blades this velocity is converted to pressure as shown in diagram.
Inlet Casing
Directs the outside air flow into the compressor
Low Pressure Air Seal
Bearing #1 Assembly
Forward Casing
Stator Blading for 0 to 3 stages
4th Stage Air Extracted
Aft Casing
Stator blading for 4 to 9 Stages
10th stage Air Extracted
Discharge Casing
Stator blading for 10 to 16Stages
Bulkhead contains large holes and studs to mount combustion chambers
At aft end of the bulkhead turbine shell is bolted
The combustion section consists of ten combustion chambers. Each combustion chamber is equipped with fuel nozzle, combustion liner cross firetube and transition piece. The ten combustion chambers are interconnected through crossfire tube to propagate the flame to those combustion chambers which do not have spark plug (8 & 9 Combustion chambers).
Combustion of fuel and air mixture is initiated by spark plugs with retracting electrodes. When the flame is established, It then retracts out of the way of hot combustion gases due to increase in compressor discharge pressure at about 50% speed. UV= 40-400nm(x-rays<UV<visible rays) (2 & 3 Combustion chambers).
Cross fire tubes enables flame to propagate other chambers which don’t have spark.
The transition pieces are the hot gas path link between the combustion liners and the first stage nozzle. Before the compressor discharge air flows into the combustion chamber, it must first pass around the transition pieces. This will result in cooling of transition pieces and preheating the combustion air.
After 2nd Stage buckets gases is directed into exhaust hood & diffuser (a series of turning vanes to turn the gases from axial to radial direction, minimizing exhaust hood losses)
13 thermocouples are installed in exhaust section to measure the temp of hot gases going towards exhaust duct.
Gases passes into exhaust plenum which are either introduced to atmosphere from exhaust stack through Diverter damper or directed to HRSG.
Guillotine damper???
The fuel gas system is designed to deliver gas fuel to the turbine combustion chambers at the proper pressures & flow rates to meet all of the starting, accelerating, loading requirements of gas turbine operation.
SRV stands for stop/speed ratio valve which is designed to maintain a predetermined pressure P2 at the inlet of the GCV as a function of Turbine speed.
GCV stands for gas control valve which controls the desired gas fuel flow in combustion chambers (response to the FSR command signal).
Gas fuel hydraulic trip relay
Hydraulic oil operated servo valves