Question

Explain the difference between bottoming and topping cycle co-generation plants.

Answer 1

Fuel is burned on the starting stage of gas turbine.Fuel is compressed and combustion takes place in the combustion chamber.These combustion product which is a very high temperature gas mixture goes through the blades of the gas turbine. The gas turbine blades move and produces work by  running the generator. The portion of the energy from the combustion products is converted to electrical energy.The waste heat or the exhaust gas is used to run the steam turbine. The waste heat is recovered by the heat recovery steam generator (HRSG) or boiler. These HRSG produces steam and this steam is directed towards the steam turbine blades. As a result the steam turbine moves and produces some more electricity.