合成气一步法制备高碳醇机理和集总动力学研究

C6～C18 higher alcohol is an important raw material for chemical industry, whose direct synthesis from syngas has great significance. However, there is a main key scientific problem that the thermal coupling effect and coupling reaction mechanism and lumping kinetic study of higher alcohols synthesis (HAS) from syngas catalyzed by the bi-functional catalyst which would be prepared by combining the HAS catalyst with reverse water – gas shift (RWGS) reaction catalyst. Based on it, in this study, through changing the preparation methods and conditions, and incorporating the CO hydrogenation and CO2 hydrogenation reaction performance evaluation with some related characterization results, the bi-functional catalysts with high performance, which are used for direct synthesis of higher alcohols from syngas, combined the Cu-Fe-Co-based HAS catalyst with Cu-based RWGS catalyst would be screened, at the same time, the thermal coupling effect of HAS and RWGS reaction would be explored and the thermal matching conditions of HAS reaction over bi-functional catalysts would be obtained; Furthermore, the coupling reaction mechanism of direct synthesis of higher alcohols from syngas over bi-functional catalysts would be revealed by adopting some advanced characterization methods and several temperature programmed testing technologies in situ or under continual flowing state; Moreover, the lumping kinetic model of HAS reaction would be built by adopting the lumped method. In summary, a new synthesis route of high additional value coal-based liquid products through modified F-T synthesis with not petroleum but coal as raw material would be developed in this study.

C6-C18高碳醇是重要的化工原料，由合成气一步法制备高碳醇具有重大意义，其中主要关键科学问题是“合成气制备高碳醇催化剂与逆水煤气变换反应催化剂组合的双功能催化剂催化合成气制备高碳醇的热耦合效应和耦合反应机理以及集总动力学”。围绕该科学问题，本项目将从制备方法和制备条件，结合CO+H2和CO2+H2反应及相关物化性能表征筛选出高性能的合成气一步法制备高碳醇的Cu-Fe-Co基催化剂以及Cu基逆水煤气变换反应催化剂组合的双功能催化剂，并探索高碳醇合成反应与逆水煤气变换反应的“热耦合效应”，获得双功能催化剂制备高碳醇的热匹配条件；同时，利用先进的物化性能表征手段以及各种原位或连续流动态下的程序升温测试技术，揭示双功能催化剂催化合成气制备高碳醇的“耦合反应”机理；采用集总的方法，建立集总动力学模型。本项目的研究将会开发一条新的非石油以煤为原料通过改良F-T合成制备高附加值煤基液体产品工艺路线。

以煤为原料通过改良F-T合成经合成气一步法制备高碳醇对于缓解能源危机具有重大意义。本项目从载体改性出发，结合CO+H2 和CO2+H2 反应性能评价及相关物化性能表征筛选得到了高性能的Cu-Fe-Co基合成气制备高碳醇(HAS)催化剂和Cu 基逆水煤气变换(RWGS)催化剂，并分别对它们的催化作用机理进行了探究；进而通过组合模式的考察，筛选得到了理想的双功能催化剂组合体系CZFK/Pal-B21-CZO(2.5mL) // CFCK/PMMA-2.5SBA-15(2.5mL)，探索了两种催化剂的“热耦合效应”，获得了该双功能催化剂组合体系制备高碳醇的热匹配条件；该双功能催化剂组合体系在热匹配条件下进行合成气一步法制备高碳醇，其CO转化率高达79.1%，产物中CH4和CO2选择性仅分别为7.2%和12.3%，总醇选择性为22.2%，醇时空收率为0.18 g/mL(cat.)•h，醇产物中C5+醇含量高达48.3wt%；同时，我们还利用BET、XRD、SEM、TEM、XPS、H2/CO-DRIFT等表征手段以及H2-TPR、NH3-TPD等程序升温测试技术，揭示了该双功能催化剂组合体系催化合成气制备高碳醇的“产物转化耦合反应”和“耦合作用机理”，即上层催化剂上产生的少量CO2、甲醇等小分子协同未反应的H2/CO共同促进了下层催化剂上高碳醇的合成，使醇的时空收率大幅上升，同时产物中碳数分布得到有效调整；此外，我们还研究了采用Cu4.5Zn4.5Al1甲醇合成催化剂与Cu25Fe22Co3K3/SiO2改性F-T合成催化剂组成双功能催化剂组合体系，进行合成气制备低碳醇的耦合效应和动力学研究，在此基础上，采用集总方法，对合成气一步法制备高碳醇的动力学进行了研究。值得关注的是，本项目还分别对改性凹凸棒土负载Cu-Fe-Co基催化剂催化合成气制备混合醇，以及由共沉淀法制备的Cu-Zn-Fe基催化剂催化CO2加氢制备低碳醇进行了系列研究，阐明了它们的催化作用机理，为CO和CO2加氢反应提供了性能良好且成本低廉的催化剂。最终，本项目按期完成了预定的研究任务，达到了预期研究目标；项目执行过程中，共发表标注论文7篇，均为EI/SCI收录；申请发明专利5项，已授权2项；培养硕士研究生2名。