以超支化聚合物可控制备双孔硅铝费-托合成催化剂及性能研究

Design and preparation of catalyst with high stability and controllable selectivity on Fischer-Tropsch synthesis (FTS) is one of the key challenges in FTS field. However, there are still some problems in tuning the product selectivity and understanding the nature of catalyst deactivation for conventional catalysts with complicated status. In this project, the novel bimodal aluminosilicate materials with controllable structure will be designed and prepared using hyperbranched polyester as a template, and the amido-ended hyperbranched poly (amide-ester) will be grown on the surface of the aluminosilicate materials. The FTS catalysts are obtained by loading cobalt/ruthenium on the as-prepared materials. The catalysts and bimodal aluminosilicate materials will be characterized and the effect of various factors, such as the composition of amido-ended hyperbranched poly(amide ester), bimodal structure, acidity, nitrogen doping confined effect, metal cluster size and dispersion, and deactivation mechanism of the catalyst, on FTS performance (activity, selectivity and stability) of catalysts will be studied in detail. The objective of this research is to obtain bimodal aluminosilicate materials with controllable structure as well as corresponding FTS catalysts with controllable size, high activity, good stability and controllable selectivity. In addition, this work may serve as a fundamental theoretical and guidance for FTS catalysts designing and preparing, and their further application.

高稳定性和产物选择性可控催化剂的设计制备是费-托合成研究的关键。传统载体孔道易被重质烃产物堵塞，难于深入研究影响产物选择性因素；传统催化剂的金属颗粒易漂移、团聚和脱落，使得催化剂易失活、稳定性较低。拟以超支化聚酯为模板制备结构可控双孔硅铝材料；在其表面原位合成端氨基超支化聚(胺-酯)，然后负载钴（钌）活性金属来制备费-托合成催化剂；利用双孔载体和氮固定金属解决催化剂的稳定性问题。通过表征载体和催化剂的结构和性能，研究双孔硅铝材料孔结构、尺寸的可控制备及影响因素；研究超支化聚(胺-酯)的组成、双孔结构、酸性、氮掺杂固定金属作用及活性金属粒径和分布等因素对催化剂性能（活性、选择性及稳定性）的影响规律，探索催化剂失活机理。旨在获得结构可控的双孔硅铝材料及金属颗粒粒径可控、分布均匀、活性高、产物选择性可控、稳定性高的费-托合成催化剂，为费-托合成催化剂设计制备提供科学指导和理论基础。

本项目遵循申请书所设计的思路和方法，先后研究了（1）硅铝比对费-托合成性能的影响。以ZSM-5为晶种合成的介孔硅铝材料，负载钴基催化剂，在固定床考察了催化剂的双功能催化特性，实现了产物的可控合成。在这一部份内容重点讨论了硅铝比的催化剂对费-托合成产物的选择性的关系；（2）双孔SBA-15对费-托合成性能的影响。以超支化聚合物和P123为双模板剂的基础上，合成了具有贯穿孔的双孔SBA-15材料，并负载钴基催化剂，考察了多种孔类型对费-托合成产物选择性的影响。研究结果表明，具有更多丰富孔的SBA-15材料，更有利于反应物和产物的传质，从而提高费-托合成催化剂的稳定性；（3掺氮SBA-15对费-托合成性能的影响。以端氨基超支化聚合物为氮源，考察了不同的掺氮方式对费-托合成产物的影响，并深入讨论了碳氮对费-托合成催化剂的结构和性能的影响。通过以上的研究，为深入理解费-托合成产物选择性调控和催化剂稳定性控制规律奠定基础，为费-托合成催化剂的设计开发和工业化应用提供科学指导和理论依据。本项目的工作结果为超支化聚合物在催化剂设计领域的应用提供实验基础和理论指导。本项目研究过程中，发表SCI检索论文7篇，第一标注为5篇，培养研究生3名。