Na促进的CuCoMn催化剂催化生物质合成气合成高醇

研究钠促进的CuCoMn催化剂的特性及其在生物质气化合成气合成高醇中的应用. 研究了催化剂中Na含量及合成条件(温度、压力和空速)对生物质基合成气合成高醇性能的影响. 发现CuCoMnNa_0.1催化剂较适合高醇合成, 在300 °C以下, 随着温度的上升, 碳转化率增大, 而醇选择性降低. 压力的增加有利于醇的合成, 增大空速会明显降低碳转化率, 但醇时空产率则因转换频率的增加而增大. 在所考察的范围内, 醇产率最高达到304.6 g·kg^-1·h^-1, 其中C₂₊高醇(C₂-C₆醇)占64.4% (w, 质量分数). 醇产物和烃产物均符合ASF (Anderson- Schulz-Flory)分布关系. 根据催化剂性能与表征分析, Na的加入有利于提高生物质气化合成气合成高醇的选择性和活性元素Cu、Co的分散性. X射线光电子谱(XPS)测试结果显示反应后的催化剂表面上, Cu以Cu⁺和Cu⁰的混合形式存在, 而Co则是Co²⁺/Co³⁺和Co⁰的混合物. 增加Na的含量, Cu⁰/Cu⁺比率和Co⁰的强度均随之减小.

Higher Alcohol Synthesis from Bio-Syngas over Na-Promoted CuCoMn Catalyst

Na-promoted CuCoMn catalysts were successfully applied to the highly efficient production of higher alcohols from bio-syngas, which was derived from biomass gasification. The influence of Na content and synthesis conditions (temperature, pressure, and gas hourly space velocity (GHSV)) on higher alcohol synthesis was investigated. The CuCoMnNa0.1 catalyst gave the best performance for higher alcohol synthesis. Carbon conversion increased significantly with an increase in temperature at lower than 300 °C but alcohol selectivity showed an opposite trend. A higher pressure was found to be beneficial for higher alcohol synthesis. Increasing the GHSV reduced carbon conversion but increased the yield of higher alcohols. The maximum higher alcohol yield that was derived from bio-syngas was 304.6 g·kg-1·h-1 with the C2+ alcohols (C2-C6 higher alcohols) of 64.4% (w, mass fraction) under the conditions used. The distributions of the alcohols and the hydrocarbons were consistent with Anderson-Schulz-Flory (ASF) plots. Adding Na to the CuCoMn catalysts led to an increase in the selectivity toward the higher alcohols and promoted the dispersion of the active elements, copper and cobalt. X-ray photoelectron spectroscopy (XPS) results suggested that Cu was present as a mixture of Cu+ and Cu0 on the catalyst′s surface after use and Co was present as a mixture of Co2+/Co3+ and Co0. With an increase in sodium addition the Cu0/Cu+ ratio and the Co0 intensity both decreased.