The Michigan Department of Environmental Quality on Nov. 21 issued a final air Permit to Install (PTI) that would allow EES Coke Battery LLC to make changes at its existing coke oven battery in the Detroit area.
EES Coke. among other things, proposed in this application is to remove the daily and annual heat input restrictions on the combustion of coke overn gas (COG) that is used to heat the battery, and to increase the material throughput limit on the amount of coal that can be processed in the battery.
EES Coke owns and operates a by-product recovery coke oven battery consisting of eighty-five, six-meter high ovens with an integral heating system; a by-product recovery plant; and a COG flare. Material handling processes in support of the operation of the battery include coal and coke transfer as well as screening and transport. The coke oven battery bakes coal into metallurgical coke for use in the iron and steel industry.
The by-product recovery coke oven battery began operation in 1992. National Steel Corp.-Great Lakes Division originally owned and operated it as well as the steel-making operations on Zug Island in River Rouge. In 1997, National Steel sold the battery to EES Coke but continued to manage the coke operations. In 2003, U.S. Steel acquired the iron and steel assets from National Steel and in 2004 EES Coke assumed sole responsibility for the coke operations. EES Coke is part of DTE Energy Services, an unregulated subsidiary of DTE Energy (NYSE: DTE).
The coke oven battery consists of 85 individual ovens that are heated with an underfire combustion system. A by-product of heating the coal to produce coke is COG. The COG is processed on-site in the by-product recovery plant that removes tars, light oils and ammonia. The COG is then used to heat the battery, sent to U.S. Steel or sent offsite. Any excess COG is combusted in the on-site COG flare. The coke oven battery was originally permitted to be heated with a mix of blast furnace gas (BFG) and COG. Due to a system failure in the coke oven battery, BFG is no longer combusted in the underfire combustion system used to heat the battery. The combustion of only COG to heat the battery results in higher emissions of NOx due to the nature of the fuel.