10-11-2012, 12:17 PM
PRESANTATION ON GAS POWER PLANT
GAS TURBINE POWER PLANT.pptx (Size: 2.94 MB / Downloads: 61)
GAS TURBINE POWER PLANT
A gas turbine power plant consists of a gas compressor, fuel combustors and a gas expansion turbine coupled to an electric generator.
Air is compressed in the gas compressor and energy is added to the compressed air by combusting gas or liquid fuel in the combustor producing power to drive the turbine rotor.
The turbine and generators are housed in enclosures designed to eliminate noise.
The turbine is highly efficient
SOME DEFINATION
Compressor
As air flows into the compressor, energy is transferred from its rotating blades to the air. Pressure and temperature of the air increase.
Most compressors operate in the range of 75% to 85% efficiency.
Combustor
The purpose of the combustor is to increase the energy stored in the compressor exhaust by raising its temperature.
Turbine
The turbine acts like the compressor in reverse with respect to energy transformation.
Most turbines operate in the range of 80% to 90% efficiency.
Gas Turbine Major Sections
Air Inlet
Compressor
Combustion System
Turbine
Exhaust
Support Systems
OPEN CYCLE
Open cycle gas turbine Basic gas turbine It consists of a compressor, a combustion chamber and a gas turbine .
The compressor and the gas turbine are mounted on the same shaft
The compressor unit is either centrifugal or axial flow type.
CLOSED CYCLE
Closed cycle gas turbine It consists of a compressor,air heater, turbine & a cooler.
Fuel is burnt externally & heat is supplied to working substance in heater.
It is an external combustion turbine.
Advantages of closed cycle gas turbine
Closed cycle gas turbine External combustion plants so wide variety of fuel can be burned in closed cycle gas turbine whereas only air can be used as working fluid in open cycle gas turbine.
Products of combustion do not come directly in contact with turbine blades in closed cycle gas turbine.
Disadvantages of closed cycle gas turbine:
Disadvantages of closed cycle gas turbine External furnace for combustion process.
More complicated and costly.
System must be strong enough to resist high pressures. Coolant is used for pre-cooling whereas no coolant is required in open cycle gas turbine.
Difference between Open cycle and closed cycle gas turbine?
The open cycle exausts the gases (produced by combustion) directly to atmosphere, sometimes the heat can be reclaimed to be utilised in a combined system (Rankine cycle added to gas cycle).
Where as the closed cycle will reuse the gasses from the exaust instead.