OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
A REVIEW OF COMBINED CYCLE POWER PLANT
THERMODYNAMIC CYCLES
Nikhil Dev 1* , Samsher 2 , S. S. Kachhwaha 3 , Rajesh Attri 1
1 YMCA University of Science and Technology, Faridabad, Haryana, India.
2 Delhi Technological University, Delhi, India
3 Pandit Deendayal Petroleum University, Gandhinagar, India
nikhildevgarg@yahoo.com
ABSTRACT
Simple cycle gas turbine engines suffer from limited efficiencies and consequential dominance of fuel
prices on generation costs. Combined cycles, however, exploit the waste heat from exhaust gases to boost
power output, resulting in overall efficiencies around 50%, which are significantly above those of steam
power plants. This paper reviews various types of combined cycles, including repowering, integrated
gasification and other advanced systems.
INTRODUCTION
The interest in the combined cycle operation was aroused through the world in mid 1970’s. During the last
two decades a number of alternative combined cycle concepts have been developed. In this chapter, a
detailed review of literature on combined cycle power plant has been undertaken, which evaluates various
gas/steam combined cycle arrangements consisting of a gas turbine coupled to an alternative bottoming
cycles. In addition the methods of thermodynamic analysis and simulation of these power plants available
in the literature have been briefly reviewed.
Figure.1. Schematic flow diagram of Combined Cycle Power Plant.
Working of a typical combined cycle power plant shown in figure 1 is explained in this section. The air at
the ambient temperature is compressed by the air compressor and directed to the combustion chamber. The
compressed air mixes with the natural gas from the fuel supply system to produce hot combustion gas in
the combustor. The hot combustion gas is delivered to the gas turbine where the power is generated. The
exhaust gas passes through a heat recovery steam generator where water is converted to high pressure
steam. The high pressure steam from the boiler drives the steam turbine. The spent steam from the turbine
flows into the condenser. The steam is separated in the boiler drum and supplied to the super heater section
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