What are the Benefits of Waste Heat Recovery systems in Industry? List down Waste Heat Recovery sources in a industry.

Benefits of Waste Heat Recovery System:

• Reduce emissions

•  Recovery of waste heat has a direct effect on the efficiency of the process. This is reflected by reduction in the utility consumption & costs, and process cost.

• Improve heating system efficiency. Energy consumption can be reduced 5% to 25%.

• Reduction in the utility consumption & costs, and process cost.

• Reduction in pollution. A number of toxic combustible wastes such as carbon monoxide gas, sour gas, carbon black off gases, oil sludge.

• Reduce flue gas temperature in chimney. So, less heat is wasted.

• Decrease fuel consumption

• Reduction in equipment sizes. Waste heat recovery reduces the fuel consumption, which leads to reduction in the flue gas produced. This results in reduction in equipment sizes of all flue gas handling equipments such as fans, stacks, ducts, burners, etc.

• Faster furnace starts up. Combustion air preheating heats furnaces better and fasters.

• Reduction in auxiliary energy consumption. Reduction in equipment sizes gives additional benefits in the form of reduction in auxiliary energy consumption like electricity for fans, pumps etc..

     WHR sources in a typical industry is given below:

1. Heat in flue gases. Higher the temperature, the grater the potential value for heat recovery. Steam boiler exhaust, Gas turbine exhaust, reciprocating engine exhausts etc…
2. Heat in vapour streams. When condensed latent heat also recovered.
3. Heat losses in cooling water. Useful heat gains if heat is exchanged with incoming fresh water.
4. Convective and radiant heat Low grade. If collected may be used for space heating.
5. Heat in gaseous and liquid effluents leaving process. Poor if heavily contaminated and thus requiring alloy heat exchanger.
6. Heat stored in products leaving the process. Quality depends upon temperature.