A Cu-Zn-Al methanol catalyst combined with HZSM-5 was used for dimethyl ether (DME) synthesis from a biomass-derived syngas containing nitrogen. The syngas was produced by air-steam gasification of pine sawdust in a bubbling fluidized bed biomass gasifier with a dry reforming reaction over ultra-stable NiO-MgO catalyst packed in a downstream reactor for stoichiometric factor (H2, CO, CO2) adjustment. It constantly gave syngas with H2/CO ratio of 1.5 and containing trace CH4 and CO2 during a period of 150 h. The obtained N2-containing biomass-derived syngas was used directly for DME synthesis. About 75% CO per-pass conversion and 66.7% DME selectivity could be achieved under the condition of 533 K, 4MPa and 1,000-4,000 h-1. The maximized DME yield, 244g DME/Kgbiomass (dry basis), was achieved under a gasification temperature of 1,073 K, ER (Equivalence Ratio) of 0.24, S/B (Steam to Biomass Ratio) of 0.72 and reforming temperature of 1,023 K with the addition of 0.54 Nm3 biogas/Kgbiomass (dry basis).
Faaij A, Hamelinck C, Tijmensen M, Long term perspectives for production of fuels from biomass; integrated assessment and R&D priorities-preliminary results. In: Kyritsis S. et al., editors, Proceedings of the First World Conference on Biomass for Energy and Industry, UK: James & James Ltd, 2, 687, 2001
Williams RH, Larson ED, Katofsky RE, Methanol and hydrogen from biomass for transportation, Princeton, New Jersey, USA: Princeton University/Center for energy and environmental studies, 1994