Integration of coal pyrolysis process with iron ore reduction: Reduction behaviors of iron ore with benzene-containing coal pyrolysis gas as a reducing agent

An integrated coal pyrolysis process with iron ore reduction is proposed in this article. As the first step, iron oxide reduction is studied in a fixed bed reactor using simulated coal pyrolysis gas with benzene as a model tar compound. Variables such as reduction temperature, reduction time and benzene concentration are studied. The carbon deposition of benzene results in the retarded iron reduction at low temperatures. At high temperatures over 800 °C, the presence of benzene in the gas can promote iron reduction. The metallization can reach up to 99% in 20 min at 900 °C in the presence of benzene. Significant increases of hydrogen and CO/CO2 ratio are observed in the gas. It is indicated that iron reduction is accompanied by the reforming and decomposition of benzene. The degree of metallization and reduction increases with the increasing benzene concentration. Iron oxide can nearly completely be converted into cementite with benzene present in the gas under the experimental conditions. No sintering is found in the reduced sample with benzene in the gas.

Graphical abstractAn integrated coal pyrolysis process with iron reduction was proposed. Opposite effects on iron reduction were observed at low and high temperatures due to the presence of a large amount of coal tar in coal pyrolysis gas. Iron oxide can nearly completely be reduced to cementite with coal tar present in the gas. The content of coal tar in the pyrolysis gas has a significant effect on iron reduction.Figure optionsDownload full-size imageDownload as PowerPoint slide