Improving coke-plant efficiency by dry quenching with natural gas

Abstract

The energy efficiency of a coke plant may be increased if natural gas is used in dry quenching of the coke. The heat from the decomposition products of the natural gas is employed to boost steam generation in the waste-heat boiler. In addition, the solid carbon produced in decomposition increases the coke strength. The material and thermal balance of the dry-quenching system is calculated. A TQ diagram of the heat-transfer process in the waste-heat boiler is plotted. If dry quenching with natural gas were used for all the coke produced at a full-cycle steel plant, it would be possible to use turbines of unit power 40–65 MW. The economic benefit may be assessed in terms of the decrease in coke consumption in the blast furnace and the increased power generation thanks to utilization of the coke’s waste heat, with corresponding reduction in fuel purchases.