Co-Electrolysis of Simulated Coke Oven Gas with Carbon Dioxide Using a Solid Oxide Electrolysis Cell

Coke oven gas (COG) is a byproduct of coke production typically composed of 57 vol% hydrogen, 27 vol% methane, 7 vol% carbon monoxide and impurities. It is partially re-utilised within steelmaking, with surplus flared and released to the atmosphere, significantly contributing to industrial carbon emissions and wasting a valuable resource. This study has investigated coelectrolysis of simulated COG (CH4/H2 mixtures) with a CO2 cooxidant using a commercially available anode-supported solid oxide electrolysis cell at 750 °C. The electrical performance of the cell was characterised using electrochemical techniques and the product gas composition was analysed using quadrupole mass spectrometry. With a 1:1 fuel-to-oxidant ratio, catalytic processes accounted for 68 % of synthesis gas production, and a further 14 % gain was achieved when operating in electrolysis mode at 1.4 V. H2/CO ratios of 1.1-2.4 were obtained depending on the fuel-tooxidant ratio of the feed. Decreasing the fuel-to-oxidant ratio improved the electrical performance and durability of the cell but decreased the overall synthesis gas yield.