Authors: Roberto García (INCAR-CSIC), María Victoria Gil (INCAR-CSIC), Fernando Rubiera (INCAR-CSIC), De Chen, Covadonga Pevida (INCAR-CSIC)

Article published on: Energy



H2 production from biogas (60%CH4 + 40%CO2) by sorption enhanced steam reforming (SESR) was thermodynamically and experimentally studied in a fluidized bed reactor. Biogas is an interesting renewable biomass resource for hydrogen production due to its sustainable nature. SESR combines the catalytic reforming reaction of biogas with simultaneous CO2 removal in a single step. A Pd/Ni-Co hydrotalcite-like material (HT) was used as catalyst and dolomite as CO2 sorbent. The effects of temperature (550-800 ºC), steam/CH4 molar ratio (2-6) and gas hourly space velocity (GHSV) (492-3937 mL CH4 gcat-1 h-1) on the process performance were evaluated. CO2 in biogas was effectively removed by the sorbent from the gas phase at 550-700 ºC, without influencing the reforming process. H2 yield increased with temperature from 550 to 650 ºC, but H2 concentration decreased at temperatures higher than 600 ºC, requiring a tradeoff between both parameters to select an optimum operating temperature. H2 purity of 98.4 vol.% was obtained at 550-600 ºC and H2 yield of 92.7% was reached at 650 ºC. Higher steam/CH4 ratios enhance the process, whereas higher space velocities decrease H2 yield. Results demonstrate that high-purity high-yield biohydrogen can be produced by the SESR of a renewable biomass resource as biogas.