Hydrogen production from coke oven gas by methane reforming: Thermodynamic analysis and experimental study

Abstract

A thermodynamic analysis of the partial oxidation of methane (POM) in coke oven gas (COG) was carried out. The optimized conditions were CH4/O2 molar ratios of 1.7-2.1 and reaction temperatures of 825-900°C. We obtained CH4 conversions of 91.0%-99.9%, H2 selectivity of 87.0%-93.4%, and CO selectivity of 100%-107% at 1.01×105 Pa. The effect of H2 in the COG on the performance of POM was also investigated between 825 and 900°C. The optimized volume ratio of steam addition was 2%-4% and the molar ratio of CH4/O2 was 2 at 1.01×105 Pa and 825-900°C. A maximum conversion rate of 98.6% was achieved for CH4 using COG, while the maximum selectivities of H2 and CO were 96.4% and 107%, respectively. The amount of hydrogen obtained after reforming was doubled despite a thermal consumption of only 2.94 J· mol-1 for the COG. The performance of a NiO/MgO solid solution catalyst packed on a BaCo0.7Fe0.2Nb0.1O3-δ (BCFNO) membrane reactor was also investigated for the POM in COG. The reforming process was successfully performed. At 875°C, 95% CH4 conversion, 80.5% H2 selectivity, and 106% CO selectivity at an oxygen permeation flux of 16.3 mL·cm-2·min-1 were achieved. The results for POM reforming in COG on the membrane reactor were consistent with the thermodynamic analysis. The NiO/MgO solid solution catalyst, therefore, has good activity and is suitable for application in hydrogen production. © Editorial office of Acta Physico-Chimica Sinica.