Waste heat is heat, which is generated in a process by way of fuel combustion or chemical reaction, and then “dumped” into the environment even though it could still be reused for some useful and economic purpose. Large quantity of hot flue gases is generated from Boilers, Kilns, Ovens and Furnaces. If some of this waste heat could be recovered, a considerable amount of primary fuel could be saved.
Waste heat recovery employs a process that has been around since the 1960s called the organic Rankine cycle (ORC), which easily integrates into existing manufacturing infrastructures. ORC units capture heat that is currently being released into the atmosphere and converts it into useable CO2-free electricity. This technology has a small footprint, approximately the size of a tractor trailer flatbed and interest in systems that use this energy generating skid is on the rise as companies look to maximize the efficiency of existing investments and infrastructures.
ORC employs environmentally benign refrigerants in a closed-loop system that turn waste heat into useable electricity. Given its relative simplicity, carbon neutrality and diminutive physical footprint, ORC is one of the most inexpensive sources of renewable power generation. Also, its high utilization rate (95%) far eclipses the 25-35% utilization rates seen in other renewable technologies, such as solar and wind.
A wave of new project development activity has occurred as a result of rising energy costs and growing environmental concern. Recent improvements in the ORC manufacturing process have made the systems modular, customizable, and easily deployed. Also, the rise of independent project managers has also hastened adoption; allowing customers to focus on energy savings while project managers design, engineer, construct and operate the plants.
Waste heat recovery delivers a win-win clean energy solution. By tapping into existing but unused energy sources companies reduce energy spending, reduce carbon footprints and reduce dependence on non-renewable sources of energy. And that’s why waste heat is about to become a lot more relevant.
Benefits:
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.
Reduction in pollution: A number of toxic combustible wastes such as carbon monoxide gas, sour gas, carbon black off gases, oil sludge, Acrylonitrile and other plastic chemicals etc, releasing to atmosphere if/when burnt in the incinerators serves dual purpose i.e. recovers heat and reduces the environmental pollution levels.
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.
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..
Links and Sources:
ENN ,
Rashid's Blog: An Educational Portal 
KGRA is an independent waste heat recovery project developer. We design, build, and sell or manage fully-integrated packaged renewable energy solutions.
KGRA Energy uses organic Rankine cycle power modules to convert the heat we harvest from engines, turbines, and other heat sources to create renewable electricity. Then we sell this generated power back to the heat host or electrical grid at favorable prices.
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