Sustainable Mining and Metallurgy

A large amount of hydrogen-enriched COG will be produced during the coking process of iron and steel plants. To tackle the low utilization rate of the hydrogen-enriched tail gas, a hybrid process combining membrane separation and pressure swing adsorption (PSA) is proposed for hydrogen recovery and is used in the production unit of a large iron and steel complex. Based on the simulation and optimization of the hybrid process with Aspen HYSYS, the effects of membrane feed pressure upon membrane area, hydrogen recovery rate, total power consumption of compressor and annual economic profitability are studied. The study shows that as the increase of membrane feed pressure, the membrane area is gradually reduced, the total power consumption of compressor is ever increasing, the annual economic profit is on the decline, while the hydrogen recovery rate has not been affected. Under the operation pressure of 2500kPa, the membrane area is 550m², the hydrogen recovery rate is 81.1%, the purity of hydrogen product is 99.9%, and the annual economic profit is 5.89×106CNY. By adopting the hybrid process, the hydrogen in COG can be recovered at a high rate and with high purity.