Ironmaking System Including Coproduction of Carbon-Loaded Iron Oxide and Reformed Coke Oven Gas by Chemical Vapor Infiltration Process

Abstract

Ironmaking system including coproduction of carbon-loaded iron oxide and reformed coke oven gas (COG) using coal tar, limonite ore, and waste heat is proposed to solve resource and energy problems in steelworks. In the proposed system, limonite ore, which is a low-grade iron ore with combined water, is first dehydrated to obtain a mesoporous solid. Then, during the chemical vapor infiltration, iron ore reduction, and reforming processes, the tar contained in the COG is deposited, leaving carbon in the mesopores of the ore. The ore is reduced by the COG and the tar is reformed by the combined sensible heat of the slag and COG, which acted as a heat source with the ore as a catalyst. The purpose of this study is to estimate the feasibility of the proposed system by process simulation using the Gibbs free energy minimization technique from the viewpoints of (1) the amount of coke required in steelworks, (2) the total chemical exergy of reformed COG, (3) the mass fraction of carbon deposited on carbon-loaded prereduced iron ore, and (4) available supplies of heat from the coke oven system to other systems under the reasonable assumptions given. The results of the analysis showed that, compared to the conventional ironmaking process, the proposed system can help decrease coke requirements by 9.62 % and increase the total chemical exergy by 14.2 %.