Many industrial operations have large electrical and thermal needs. In many industries (e.g. food, paper and pulp, chemicals, petroleum refining, etc.), thermal loads are very significant and represent 65-90% of total energy consumption (see figure). Therefore, industrial sites are excellent prospects for both topping and bottoming CHP installations. Waste gas streams and flared gases can be integrated into the CHP system. Many industrial waste heat streams have temperatures over 2000° F, making them ideal for CHP. For example, 60% of the total heat input is wasted in flue gases at 2000° F. The use of excess air in industrial process makes this even worse. Bottoming installations in particular can be used to capture waste heat that is currently exhausted into the atmosphere. Energy that is recovered from waste heat streams could displace part or all of the energy input needs for a unit operation within a plant. Waste heat recovery offers a great opportunity to productively use this energy, reducing overall plant energy consumption and greenhouse gas emissions. Furthermore, increased reliability and power quality can also add a significant value.
Energy Use Pattern for Major Industries
[Source: Waste Heat to Power Generation Workshop - DOE EERE-ITP Presentation, UC Irvine, CA, March 2005]
The following industries could make excellent hosts for CHP installations: