一步法加氢制生物航煤催化剂研究进展

Development in catalysts for one-step hydrogenation of bio-jet fuels

与两步法制航煤相比,一步法生产过程具有成本低、反应步骤简单、能源消耗低等优点。一步法高效制航空煤油的关键是催化剂的选择,催化剂需要同时具有加氢脱氧、异构和选择性裂化等性能。本文阐述了近年来植物油一步加氢制航煤双功能催化剂的选择与制备,并介绍了双功能催化剂中酸中心与金属中心对反应的贡献。具有十元环孔道的微孔分子筛具有独特的异构烃选择性,但与介孔分子筛相比,反应物与产物分子扩散阻力较大,因此合成分级孔分子筛或介微孔复合分子筛是未来催化剂载体的较优选择。同时探讨了活性金属对催化反应活性的影响,与贵金属催化剂相比,双金属、过渡金属、过渡金属硫化物与过渡金属磷化物表现出优异性能的同时可以降低成本。最后探讨了催化剂的制备方法对活性物种分散度的影响,高分散的过渡金属催化剂在反应过程中显示出更高的反应活性。

Compared with the two-step process for bio-jet fuel production,the one-step process has the advantages of low cost,simple reaction and low energy consumption.The key to the efficient production of jet fuel by one-step process is the selection of catalysts,which need to have the integrated ability of hydrodeoxygenation,isomerization,and selective cracking.This work reviews the selection and preparation of bifunctional catalysts for the one-step hydrogenation of vegetable oil to jet fuel in recent years,and introduces the contribution of acid center and metal center to the reaction in the bifunctional catalysts.Microporous zeolites with 10-ring pores have unique selectivity for isomeric hydrocarbons.Compared with mesoporous materials,microporous zeolite provides larger diffusion resistance of reactants and products.Therefore,the synthesis of hierarchical porous materials or meso-microporous composites is a preferred choice of catalyst supports for future catalysts.The effect of active metal on the catalytic reactivity is also explored.The bimetallic,transition metals,transition metal sulfides and transition metal phosphides catalysts exhibit superior performance and cost reduction,compared to noble metals catalysts.Finally,the effect of catalyst preparation methods on the dispersion of active species is explored.Catalysts supported by highly dispersed transition metals exhibit excellent reactivity.