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

Abstract

The recovery of energy and valuable compounds from exhaust gases in the iron and steel industry deserves special attention 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 environmental benefits in the iron and steel industry. COG is presently used for heating purposes in coke batteries or furnaces, while in high production rate periods, surplus COG is burnt in flares and discharged into the atmosphere. Thus, the recovery of the valuable compounds of surplus COG, with a special focus on hydrogen, will increase the efficiency in the iron and steel industry compared to the 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 provide additional hydrogen from the chemical transformation of the methane contained in COG, and iii) direct use of COG as fuel for internal combustion engines or gas turbines with the aim of power generation. In this study, the strengths and bottlenecks of the main hydrogen recovery routes from COG are reviewed and discussed.

Valorizing Steelworks Gases by Coupling Novel Methane and Methanol Synthesis Reactors with an Economic Hybrid Model Predictive Controller

“…b COG composition measurement takes place after a gas cleaning unit (i.e., filter or desulphurization). c POG compositions are in good agreement with the values given in the BAT document [6] and in further literature papers [7][8][9]. d Mixed enriched gas is mainly used in power plant, coke ovens, and blast furnaces.…”

Regenerativ erzeugter Wasserstoff – Perspektiven in chemischen Wertschöpfungsketten

“…Neben den hier aufgefu ¨hrten großtechnischen Verfahren gibt es noch weitere Prozesse, bei denen Wasserstoff als Nebenprodukt anfa ¨llt. So entha ¨lt beispielsweise Hochofengas aus der Stahlherstellung zwischen 40 und 65 % Wasserstoff [55]. Im Jahr 2020 wurden so 3-5 Mt Wasserstoff erzeugt.…”

Comparative Lifecycle Assessment of Methanol and Urea Produced from Steel Mill Gases

“…Hydrogen is supplied by the same off-gases, as well as the electrolyzer, PSA of COG (75 % H 2 recovery) and purge gas PSA from ammonia synthesis reactor (90 % H 2 recovery). PSA of COG has lower H 2 recovery due to presence of CO and N 2 as contaminants for PSA process [27].…”