生物质气经由二甲醚两步法制备低碳烯烃

制备出NiSAPO-34及NiSAPO-34/HZSM-5催化剂，考察了其对二甲醚催化转化制备低碳烯烃的性能．利用Cu/Zn/Al/HZSM-5和筛选出的2%NiSAPO-34/HZSM-5催化剂进行生物质气经由二甲醚两步法制备低碳烯烃的实验， 结果表明在SAPO-34上添加2%的Ni不改变其结构， 但降低了酸中心数量， 并生成了较强的酸中心． 添加少量具有稳定酸中心的HZSM-5， 该催化剂的活性提高到3 h以上， 反应进行2 h获得了最高的低碳烯烃选择性为90.8%． 当把该催化剂应用到两步催化转化过程的第二个反应器中， 其高催化活性可达5 h以上． 当以低氢碳比生物质气(H₂/CO/CO₂/N₂/CH₄=41.5/26.9/14.2/14.6/2.89)作为原料时，经两步转化，低碳烯烃的收率达到84.6 g/m³_syngas．

Production of Light Olefins from Biosyngas by Two-stage Catalytic Conversion Process via Dimethyl Ether

NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether (DME) conversion to light olefins (DTO). The processes of two-stage light olefin production, DME synthesis and the following DTO, were also investigated using biosyngas as feed gas over Cu/Zn/Al/HZSM-5 and the optimized 2%NiSAPO-34/HZSM-5. The results indicated that adding 2%Ni to SAPO-34 did not change its topology structure, but resulted in the forming of the moderately strong acidity with decreasing acid amounts, which slightly enhanced DME conversion activity and C₂=_-C₃= selectiv-ity. Mechanically mixing 2%NiSAPO-34 with HZSM-5 at the weight ratio of 3.0 further prolonged DME conversion activity to be more than 3 h, which was due to the stable acid sites from HZSM-5. The highest selectivity to light olefins of 90.8% was achieved at 2 h time on stream. The application of the optimized 2%NiSAPO-34/HZSM-5 in the second-stage reactor for DTO reaction showed that the catalytic activity was steady for more than 5 h and light olefin yield was as high as 84.6 g/m³_syngas when the biosyngas (H₂/CO/CO₂/N₂/CH₄=41.5/26.9/14.2/14.6/2.89, vol%) with low H/C ratio of 1.0 was used as feed gas.