250MWe from Energy Recycling
NPR recently posted an in-depth article on bottom-cycling and waste heat recovery in industrial process as a growth area. Featured in the report was the massive ArcelorMittal steel mill in East Chicago, Indiana and its approach to becoming more efficient which includes the installation of boilers above the coke ovens, which generate on the order of 100MWe, or 2,400 MWh per day.
They’ve also taken advantage of pressure differential noticing that the gas that arrives to power their plant is delivered at 30 psi, the pressure at which the gas efficiently burns is 3 psi. So the company has installed turbines inline to harvest the energy in the pressure differential to generate even more power, about 16MWe or 384MWh per day.
The waste heat and gases from the process are also being harvested (bottom cycling) from the exhausted gases yielding a further 65-70MWe. In total, this complex is recovering around 250MWe from its various energy recycling programs offsetting 1,300,000 tons of CO2 emissions per year and satisfying nearly 50% of the factories energy needs.
DOE studies suggest US industries waste enough heat to harvest an estimated 200,000MWe from the processes, nearly 20% of total present US generation capacity. Clearly, this is an opportunity for improvement and recovery of existing resources and with energy prices steadily climbing, more of these programs will undoubtably be implemented.
Links:
National Public Radio Report on Energy Recycling
