In a topping cycle, utilization of fuel burnt is mainly for the productions of electricity and excess thermal energy is recovered.
Heat energy is generated as a byproduct of the cycle, which is used to attain the thermal requirements or satisfy process heat.
Four types of topping-cycle cogeneration system are,
- Combine d cycle topping system
- Steam turbine topping system
- Heat recovery topping system
- Gas turbine topping system.
Combine d cycle topping system
- Basically, fuel and air are burnt in a combustion chamber and combustions gases thus produced.
- Mechanical or electrical power is generated by an associated rotary engine or gas turbine.
Steam turbine, topping system
- In this system, high pressure, as well as low-pressure steam, is produced.
- Any type of fuel is burnt and a high-pressure steam is produced which is then passed on a steam turbine to produce electric power.
Heat recovery topping system
- This water absorbs additional heat from an engine.
- It is run through a heat recovery boiler which can either transformed to process steam or hot water.
Gas turbine topping system
- This system from the turbine is passed through a heat recovery boiler.
- This exhaust energy is converted to usable heat/steam.