以杂多酸为前驱物Co-Mo基催化剂的构建及其高浓度CO变换制氢性能

It is a very important topic for high quality and efficient utilization of high-sulfur petroleum coke in inferior crude oil processing industry. Hydrogen production by the water-gas-shift reaction is one of the most effective ways, and the key is to develop sulfur tolerant shift catalyst with high performance. However, under the conditions of high concentration of CO and low ratio of vapor to gas, typical Co-Mo-based sulfur tolerant shift catalyst that supported on magnesia alumina spinel shows poor activity, and catalyzes other side reactions such as methanation and Fischer-Tropsch synthesis. In this project, a new way for preparing high-efficiency Co-Mo-based sulfur tolerant catalyst is proposed by using heteropolyacid as precursor. In this project, the heteroatom, polyatom, metal element, and clusters of heteropolyacid will be adjusted and the heteropolyacid with different structure and Co/Mo percentage will be synthesized. Using the prepared heteropolyacid as precursor and the magnesia alumina spinel as the support, Co-Mo-based sulfur tolerant catalyst with controllable composition and structure will be designed and prepared. Moreover, based on the catalyst characterization and the catalytic performance evaluation, the composition and structure of the active phase will be revealed and the relationship between the composition, structure, and property will be established. The achieved findings can not only provide a theoretical foundation and technical source for the development of new Co-Mo-based sulfur catalyst, but also are practically significant for the efficient utilization of high-sulfur petroleum coke.

高硫石油焦的高质高效利用是劣质原油加工产业链中迫切需要解决的重要课题，高硫石油焦气化后变换制氢是最高效途径之一，其关键是研发高性能的耐硫变换催化剂。项目针对镁铝尖晶石为载体的Co-Mo基耐硫变换催化剂在高浓度CO、低汽气比等条件下制氢存在活性较差、易发生甲烷化和费-托合成等副反应等问题，拟利用Co-Mo基杂多酸中杂原子、多原子、助金属元素以及簇与簇之间的可调变，合成不同结构和Co/Mo比的杂多酸，并以其为前驱物，以镁铝尖晶石为载体，设计和制备出组成和结构可控的Co-Mo基耐硫变换催化剂。通过对催化剂组成、结构和性能的表征，揭示活性相的组成和结构，建立活性相组成-结构和催化性能之间的构性关系。这不仅能为发展新型Co-Mo基耐硫变换催化剂的调控和制备方法奠定理论基础和提供技术源头，而且对于高硫石油焦高效利用具有重要的实际意义。

高硫石油焦的高质高效利用是劣质原油加工产业链中迫切需要解决的重要课题，高硫石油焦气化后变换制氢是最高效途径之一。为此，本项目从三个方面进行了研究：首先，开展了不同Co-Mo前驱物的合成及高性能Co-Mo/ MgAl2O4 催化剂的制备研究，发现了助剂Co可以促进催化剂中CoMoS物种的形成，低温阶段（<300 ℃）CoMoS位点较纯MoS2具有更高的水煤气变换活性，而高温阶段（>300℃），CoMoS与MoS2水煤气变换活性相当。其次，开展了Co-Mo/MgAl2O4 催化剂活性相结构和构效关系研究，发现了柠檬酸可以调控Co-Mo前驱物的配位方式，拓宽Co-Mo催化剂的硫化温度区间，促进CoMoS活性位点的形成，进而实现催化剂活性的调控。发明了助剂Co的直接高分撒于载体，利用Co的锚定作用制备出MoS2活性相堆垛层数少，片层长度短，催化活性高的Co-Mo耐硫变换催化剂。最后，考察了助金属元素对催化剂活性和稳定性的促进作用，发现了稀土元素的添加可增强载体表面的碱性，促进钴钼的分散，降低硫化态催化剂中MoS2堆垛层数和堆垛长度，暴露MoS2更多的活性位点，从而大大提高水煤气变换反应速率，据此，发明了通过添加稀土元素制备高活性耐硫变换催化剂的新方法。上述研究结果为发展新型Co-Mo基耐硫变换催化剂的调控和制备方法奠定理论基础，对高硫石油焦高效利用具有重要的实际意义。