Upgrading biomass fuel gas by reforming over Ni–MgO/γ-Al2O3 cordierite monolithic catalysts in the lab-scale reactor and pilot-scale multi-tube reformer

The effect of Ni/Mg mole ratio of Ni–MgO/γ-Al2O3 cordierite monolithic catalysts on dry reforming of model biomass fuel gas(H2/CO/C2H4/CH4/CO2/N2=16.0/12.1/2.5/15.1/22.0/32.3, vol.%) was investigated in a lab-scale stainless steel tubular reactor. The results showed that CH4 and CO2 conversions, H2 and CO yields and H2/CO ratio in the tail gas was 87.2%, 54.4%, 65.2%, 43.0%, and 1.17 respectively at 750°C over the optimized MCNi0.51Mg0.49O (the ratio was 0.51:0.49 with 8.3wt% NiO loading amount) during 60h of time on stream (TOS). And the formation of NiO–MgO solid solution structure would restrain the active Ni0 centers from agglomeration and decrease carbon deposition. Cold test of the vertical-placed tubular reformers (packed by monolith of 7mm cell spacing) indicated that the pressure drop was as low as 850Pa at 1.57m/s of gas velocity with 330g/m3 fly ash added. The reforming of real biomass fuel gas (H2/CO/C2H4/CH4/CO2/N2=10.2/16.8/0.5/6.4/15.2/51.0, vol.%, from air gasification of 200–250kg/h pine sawdust in the pilot plant) in the multi-tube reformer packed with MCP (larger in size than MCNi0.51Mg0.49O) exhibits the pressure drop of less than 700Pa, CH4 and CO2 conversions of about 84% and 38.5% and the decrease of tar content from 4.8–5.3g/m3 to 0.12–0.14g/m3 during 60h TOS at 670°C. The characterization of the spent catalysts by TG, XRD and ICP-AES proved the anti-sintering and anti-carbon deposition properties of NiO–MgO solid solution monolithic catalyst.