Chapter 5 Flashcards
The preparation for start-up of a gas turbine usually assumes:
A) Starting some auxiliary systems
B) Turning on the cooling water
C) Automatic operation for remote applications
D) Subsystem checkout first
E) The start-up will be done by the operator
C
Natural gas is the best fuel for gas turbines because natural gas:
A) Is less expensive than other fuel sources
B) Has less contaminants as compared to other fuel sources
C) Promotes the most efficient combustion and produces the lowest environmental emissions
D) Has the lowest efficiency of combustion
E) Has a lower explosion risk than other fuels
C
Anti-icing systems are used to prevent:
A) Blade damage
B) Plugging of filters with ice
C) Damage to the duct work from icing
D) Compressor surging
E) Intake air temperature becoming too low
A
Gas turbines use duel fuels for:
- Consistent power delivery
- Back-up
- Increasing overall power output
- Switching to cheaper fuel
- Less complicated controls during operation
A) 2, 3
B) 1, 2
C) 4, 5
D) 2, 4
E) 3, 4
D
Routine maintenance on a gas turbine should involve checking for fuel leaks on a _______ basis.
A) Weekly
B) Daily
C) Yearly
D) Hourly
E) Monthly
B
Thrust bearings on dual shaft gas turbines are positioned:
A) At the inlet of the compressor and next to the turbine bearing
B) At the back of the compressor and next to the turbine bearing
C) At the back of both the compressor section and the turbine section
D) At the front and back of the turbine section
E) At the front of both the compressor and the turbine section
A
Turning gears are used to:
A) Rotate the shaft every hour
B) Prevent the shaft from locking
C) Prevent the shaft from developing flat spots
D) Lower the stress on the starting motor
E) Rotate the shaft 90 degrees every hour
B
Off-line washing is performed by:
A) Injecting cleaners into the inlet at 50% rated speed
B) Injecting cleaners into the inlet at zero shaft speed
C) Having the unit isolated and the speed at zero
D) Injecting cleaners at crank speed
E) Injecting cleaners at 30% rated speed
D
Inlet air temperatures to the gas turbine are reduced by:
A) Spray cooling
B) Evaporative cooling
C) Evaporative pads
D) Fog cooling
E) All of these are used
E
Gas Turbine Exhaust systems must be designed to ensure:
A) Exhaust is not recycled to the air intake
B) The muffler bearings are not damaged
C) The system is hidden from the community
D) High temperature exhaust is cooled
E) The exhaust is dissipated before release
A
The use of a low energy value fuel requires:
A) Higher pressure from the compressor
B) Larger bore piping for low flow rates
C) Higher pressure gas supply
D) Special nozzles and combustors
E) Higher pressure gas compressors
D
A rapid decrease in gas turbine speeds can result in:
A) High pressures in the turbine sections
B) Failure of the recycle valve
C) Overcooling the unit
D) Combustion being interrupted
E) High pressures in the compressor sections
D
The first piece on an air intake system is:
A) Cooling coils
B) Stainless steel screen
C) Guard filter
D) Drift eliminators
E) Heating coils
B
Liquid fuel treatment systems for Gas Turbines consist of:
A) Dewatering and chemical treatment
B) Filters, dewatering, and chemical treatment
C) Mechanical and chemical treatment
D) Centrifuges, filters, dewatering, and chemical treatment
E) All of these can be used
E
The first step in a normal gas turbine shutdown is:
A) Clove the fuel valve
B) Open the recycle valve
C) Cool down the turbine
D) Take load off the generator
E) Reduce speed to idle
E
