Burners in the steel industry: utilization of by-product combustion gases in reheating furnaces and annealing lines

The steel industry demands large quantities of raw material and energy to produce iron and steel. During the overall process, parts of the generated by-products are combustible gases, which can be valorized in different equipment of integrated steel mills. After a description of the by-product combustible gases: coke oven gas (COG), blast furnace gas (BFG) and basic oxygen furnace gas (BOFG), a focus is given on the constraints of their usage, in particular due to the constantly fluctuating composition and physical characteristics. Examples of usages in two steel mills energy intensive equipment are given: reheating furnaces comprising dozens of several MW burners and annealing lines equipped with hundreds of burners under 200 kW power output.