Hydrogen Recovery from Coke Oven Gas. Comparative Analysis of Technical Alternatives

The recovery of energy and valuable compounds from exhaust gases in the iron and steel industry deserves specialattention due to the large power consumption and CO 2 emissions of the sector. In this sense, the hydrogen content of coke oven gas(COG) has positioned it as a promising source toward a hydrogen-based economy which could lead to economic and environmentalbenefits in the iron and steel industry. COG is presently used for heating purposes in coke batteries or furnaces, while in highproduction rate periods, surplus COG is burnt in flares and discharged into the atmosphere. Thus, the recovery of the valuablecompounds of surplus COG, with a special focus on hydrogen, will increase the efficiency in the iron and steel industry compared tothe conventional thermal use of COG. Different routes have been explored for the recovery of hydrogen from COG so far: i)separation/purification processes with pressure swing adsorption or membrane technology, ii) conversion routes that provideadditional hydrogen from the chemical transformation of the methane contained in COG, and iii) direct use of COG as fuel forinternal combustion engines or gas turbines with the aim of power generation. In this study, the strengths and bottlenecks of themain hydrogen recovery routes from COG are reviewed and discussed.