沼气重整生物质燃气合成二甲醚

Synthesis of DME via Reforming Biomass Fuel Gas with Biogas

采用生物质厌氧消化制备的沼气,重整生物质空气—水蒸气气化制备的燃气,在超稳NiO MgO固溶体重整催化剂上,调整生物质合成气的化学物质的量之比,并与传统调变方法进行了分析比较.以制备的生物质合成气合成二甲醚的实验,考察了重整过程的促进效果,对系统操作参数进行了优化,对重整催化剂的活性和稳定性进行了测试和考察.结果表明,引入沼气重整,活化了生物质燃气中过量的CO2 ,制备的生物质合成气x(H2 ) x(CO)比在1 5以上,仅含痕量的CH4和CO2 ;沼气的加入量决定于生物质燃气的组成和生成速率;生物质转化为二甲醚燃料的碳转化率达到70 %以上,合成产物中二甲醚选择性达到69 6% ;与商业镍重整催化剂相比,自制的NiO MgO固溶体催化剂具有良好的高温活性、还原性和抗积碳性能,连续1 0 0h的寿命测试,未检测到积碳和晶相结构变化;与传统调变方法相比,添加沼气重整工艺简单,系统效率高。

In the present work, the biogas produced by anaerobic digestion of biomass was used to reform biomass air-steam gasification fuel gas over the ultra-stable NiO-MgO catalyst for co-generation of synthesis gas (H 2+CO). Different adjustment pathways for meeting the desired stoichiometry of the synthesis gas for the DME synthesis were compared and analyzed. The promoting effect of reforming reaction on the biomass syngas production was investigated. The activity and stability of reforming catalyst were also tested and valued. The desired stoichiometric syngas was obtained by co-reforming with biogas and biomass fuel gas. The x(H 2)/x(CO) (syngas) is above 1 5. It contains trace CH 4 and CO 2. The feeding rate of biogas depends on the composition and flow velocity of fuel gas produced in the gasifier. Above 70% of the biomass carbon content was converted to DME. The selectivity of DME in the synthesis products was increased to 69 6%. Compared with commercial nickel-based reforming catalysts, the NiO-MgO catalyst exhibits good catalytic activity, reducibility and anti-coke ability at high temperature(>750℃). The lifetime test for 100h indicates no coke formation on the surface of catalyst. It also exhibits no structure destroying after lifetime test. Compared with conventional stoichiometric factor adjustment pathways, the technology of co-reforming with addition of biogas was simple and highly effective. The composition of syngas by this technology is suitable for DME production.