Effect Of AlOOH On The Performance Of Dimethyl Ether Synthesis From Carbon Monoxide Hydrogenation In The Slurry Reactor

Dimethyl ether is the simplest ether,which is widely used in fuel,chemical raw materials,refrigerants,foaming agents and other fields.Composite catalyst for the synthesis dimethyl ether in one step by CO hydrogenation was often used Cu-based catalysts as methanol synthesis catalysts,but the two kind active sites of methanol synthesis and methanol dehydration existed a mismatched problem,resulting in poor optimal catalytic performance and unstable catalytic life.Therefore,it is of great significance to develop a new methanol dehydration catalyst.In our group,the AlOOH prepared by the complete-liquid-phase method showed good methanol dehydration performance.At the same time,it found that Al OOH prepared by different methods in the fixed reactor had obvious effects on the product distribution of the composite catalyst.In view of the great influence of the reactor type on the catalytic performance,How did the catalyst preparation method for methanol synthesis and AlOOH affect the product distribution in a slurry reactor?In this paper,a slurry reactor was used as an activity evaluation device.The influence of preparation methods and composite ratio on the performance of the composite catalyst synthesis dimethyl ether was investigated.The main conclusions were summarized as follows:1.The composite catalyst were formed by AlOOH(prepared by homogeneous precipitation method)and the methanol synthesis catalyst prepared by different methods.When it was used for CO hydrogenation in a slurry reactor,the dimethyl ethers was the main product.The composite catalyst formed by C302 and AlOOH(homogeneous precipitation method)showed higher CO conversion and dimethyl ether selectivity,which reached 31.51%and63%respectively.It was found that methanol synthesis catalyst prepared by different methods had a great influence on the crystallinity of Cu,Zn species and AlOOH.2.The composite catalyst formed by AlOOH prepared by homogeneous precipitation method had better catalytic performance than that by AlOOH prepared by sol-gel method.Having the higher crystallinity of CuO and AlOOH was benefit to improve the stability of the catalyst.3.In the slurry reactor,the optimal ratio of AlOOH and C302 was different when AlOOH was prepared by sol-gel and homogeneous precipitation method.The optimum mass ratio of AlOOH(sol-gel method)and C302 was 1:1,and the conversion rate of CO and the selectivity of dimethyl ether was 26%and 53%respectively.The best mass ratio of AlOOH(homogeneous precipitation method)and C302 was 2:1,the highest CO conversion rate reached 31.51%,dimethyl ether selectivity was about 63%.4.The mass ratio of AlOOH and C302 played a role in regulating grain size of Cu~0.Catalysts with small Cu~0 grain size,large ZnO grain size,and a greater amount of weak acid and moderately strong acid strength exhibited good catalytic activity and higher dimethyl ether selectivity.