Application Of Microimpinging Stream Reactors In The Preparation Of CuO/ZnO/ZrO₂ Catalysts For Methanol Synthesis

The reaction conditions such as feed rate,pH and concentration in the preparation of CuO/ZnO/ZrO2 catalysts by coprecipitation method have a great influence on the structure and catalytic activity.However,it is difficult for the agitated tank reactor(STR)to control these processes accurately,resulting in the uncontrollable structure and catalytic performance of the catalysts.Microimpinging stream reactors(MISR)were built with constant-flux pumps,commercial T-junction and two steel capillaries of 0.6 mm I.D.for the preparation of CuO/ZnO/ZrO2 catalysts,In which the catalyst precursors were produced by coprecipitation in MISR with precisely controlled conditions including concentration,pH and volumetric flow rate.Different sizes of impact space and volume flow have important effects on precursors and catalysts.The optimum flow rate is about 100 mL/min.SS-2UT is the most suitable T-junction among three different T-junctions.The best aging time is 2 h and the optimum concentration is 1.2 mol/L.The CuO/ZnO/ZrO2 catalysts prepared in MISR possessed small particles and larger BET surface area.According to the element distribution analysis,the local components ratio of the catalysts prepared by MISR was more uniform and closer to the stoichiometric ratio of the reacting solutions.A variety of characterization methods were used to compare the difference between the catalysts prepared by STR and the catalysts prepared by MISR to clarify the characteristics and the reasons for these differences.The catalytic performance by CO hydrogenation to synthesis methanol and CO2 hydrogenation to synthesis methanol exhibited a higher catalytic activity.