Correct Answer - Option 4 : Combined
Explanation:
Combined cycle:
This cycle combine gas turbine Topping cycle with the steam turbine Bottoming cycle, with an energy flow hierarchy of fuel to electricity to produce electricity.
Topping cycle:
A Topping cycle is one in which the primary purpose of the input fuel is to generate electricity, and the waste heat exhausted by this process is captured and used in industrial process or for heating and cooling.
Thus, the heirarchy of the Topping cycle is fuel to electricity to process.
Bottoming cycle:
A Bottoming cycle is one in which the fuel energy has primarily been used to provide process heat first.
Waste heat from the process is then captured and used to generate electricity.
Cogeneration:
Cogeneration is normally defined as the simultaneous production of two or more forms of useful energy usually power and heat.
The major equipment associated with a cogeneration cycle traditionally includes one or more of the followings:
a) Steam generator or boiler
b) Steam turbine generator (STR)
c) Gas turbine generator (GTR)
d) Heat recovery steam generator (HRST)
e) Reciprocating spark ignited gas, dual fuel or Diesel engine generator.
The manner in which the equipment are combined and used defines the type of cogenerative cycle.
