Waste Heat Recovery System:
Waste heat recovery system is the heat which is not at all used and exhausted out as a waste product. Waste heat is normally available from the industry in the form of process steam and water at high temperature. In every type of industry, the waste heat is also discharged with the exhaust gases.
Heat from the waste hot streams is recovered either in the form of sensible heat or latent heat. When the heat is recovered in the form of sensible heat, the fluid used for carrying heat is either air (or) water.
The latent heat recovery is the most common and versatile method of waste heat recovery system when used for power generation.
In thermal and nuclear power plants, large quantity of heat at around 70°C is discharged into the atmosphere.
The following are the applications developed to use large amounts of very low temperature waste heat.
- Green houses.
- Animal shelters.
- Aquacultural uses.
- Waste heat utilization for waste water treatment.
The following are the waste material which can be used as fuel for power generation.
- Municipal waste.
- Industrial waste.
- Paper waste.
- Rubber waste.
These wastes create dumping problems and pollution problems. With the increasing prices of conventional fuels, the use of these wastes as fuel are considered as economic–proposal for power generation.
The energy content in the most of the waste material is high and great amount of energy content can be recovered if used as fuel.
Waste Heat Boilers
The waste heat boilers use the waste heat of gases coming out of diesel engines and gas turbines at high temperature (or) use the waste as a fuel in the incinerators. Some boilers use the industrial dirty gases for power generation.
Normally, fire tube boilers are used to recover the waste heat from low pressure gases exhausted by diesel engines (or) gas turbines.