Preparation And Properties Of Catalysts For Dimethyl Ether From Hydrogenation Of Carbon Dioxide

This paper mainly studied the preparation and properties of carbon dioxide hydrogenation catalyst for dimethyl ether synthesis.Under different process conditions,zirconium metal doped carbon dioxide hydrogenation catalyst was prepared using sodium carbonate as a precipitant of coprecipitation.The catalytic performance of catalysts that under different process conditions for the preparation were tested and evaluated by the catalyst evaluation device WFSM-3060,the optimal preparation conditions was selected.Using X-ray diffraction(XRD),specific surface area test(BET),scanning electron microscope(SEM)and thermogravimetric analysis(TG),and other technology to characterize the catalyst,and studied the relationship between the performance and the structure,composition of catalyst.(1)Cu-Zn-Al/HZSM-5 catalysts were prepared under different proportion of Cu/Zn,different roasting temperature and different precipitant.Roasting temperature,Cu/Zn,precipitation agent were obtained by orthogonal experiment,the highest yield dimethyl ether obtained at 350?,Cu/Zn was 2:1,precipitating agent was sodium carbonate.In addition,Cu/Zn ratio and the influence of calcination temperature on catalyst performance were further research using single factor experiment,the optimal preparation conditions were obtained finally.The catalyst with different ZrO2 doping concentration were prepared under the optimal preparation condition,and obtained the best ZrO2 doping concentration.Zr doped Cu-Zn-Al/HZSM-5 compared with the traditional catalyst for carbon dioxide hydrogenated to synthesize dimethyl ether has higher carbon dioxide conversion rate,but the yield was decreased.XRD,BET and SEM analysis suggested ZrO2 doping increased the diffraction peak intensity.And the peak became more acute,the accumulation degree increased,specific surface area reduced.(2)In order to prepare high selectivity of CO2 hydrogenation catalyst for dimethyl ether synthesis,use different Cu/Mn ratio and different roasting temperature as preparation optimization factors.Cu/Mn ratio and calcination temperature were discussed on Cu-Mn-Al/HZSM-5 catalytic properties for catalytic CO2 hydrogenation to producing dimethyl ether.The best Cu/Mn ratio and optimum calcination temperature were obtained by single factor experiments.Under the optimum technological conditions for the preparation of catalyst for ZrO2 doping,the effect of doping and doping concentration on catalyst performance were studied,and obtained the optimal ZrO2 doping concentration.Further studies found that the ZrO2 doped Cu-Mn-Al/HZSM-5 catalyst have higher selectivity of dimethyl ether,and the carbon conversion rate is also considerable.