Cyclic performance of coke oven gas - Steam reforming with assistance of steel slag derivates for high purity hydrogen production

Abstract

Steel slag-derived CaO (CaO(SS)) was applied in cyclic sorption enhanced steam reforming of coke oven gas process (cyclic SE-SRCOG) for high-purity hydrogen production. Effects of leaching acid concentration on the cyclic CO2 capture capacity of CaO(SS) were investigated. Using 1 mol/L acetic acid solution as leaching solution, the prepared CaO-based sorbent showed a stable CO2 capture capacity of 0.27 gCO2/gCaO after 35 sorption-desorption cycles. Impacts of operating modes (with different particles contents and loading patterns), operating procedure, and leaching residue (LR) blending on cyclic SE-SRCOG performance were experimentally investigated in detail. Combined catalyst-sorbent by adhesively tableting exhibited the worst stability due to loss of Ni active sites, caused by severe sintering and coverage by CaCO3. With a reforming temperature of 600 °C, cyclic SE-SRCOG with layered packing catalyst-sorbent particles could achieve H2 purity of 95% and CH4 conversion of 87% at the 5th cycle, and they were still maintained to be 87% and 65% at the 10th cycle, respectively. In operating mode using layered packed catalyst-sorbent particles, integration of LR into the sorbent facilitated further improvements of CH4 conversion to 86% at the 10th cycle, mainly due to that LR could act as catalytic promoters of SRCOG and sintering-resistance spacers of CaO(SS).