(63l) Waste Heat Recovery

Rowan engineering students working with Johnson Matthey have identified a green engineering opportunity for reducing their natural gas usage utilizing the heat contained in an exhaust gas stream. A heat exchange system was designed to recover energy from exhaust gases and use it to preheat combustion air fed to this process. Installing this new heat exchanger will increase the pressure drop on the system as well as increase the NOx produced as a result of higher combustion air temperature. To reduce the NOx produced, new ultra-low NOx burners have been specified. In addition, new fans are required to maintain the current gas flowrates in the system. Total savings based primarily on reduced natural gas consumption are estimated at $302,500/yr. The capital equipment proposed is a gas to gas heat exchanger, a combustion air fan, and a scrubber fan. In addition to reducing the carbon footprint of the furnace system, the project is economically viable as the internal rate of return is 20.7% and the payback period is 49 months. This project will reduce the CO2 emissions of the furnace system by 163 tons/yr and decrease the nonrenewable fossil fuel usage of the furnace system by recovering the waste heat generated.