Study On Preparing And Performance Of Complex Metal-oxide Catalysts

The using aera of acrylic acid (AA), which is important raw material of chemical industry, is spreading. Compared with the two steps-oxygenation of propylene to prepare acrylic acid, the oxygenation of propane has the advantages of cheaper raw material and briefer preparing process. Besides, it uses the saturated hydrocarbon economically. So, it's an ideal way to prepare AA.In this paper, we compared different complex metal-oxide Mo-V-Te-Nb-O catalysts prepared by different ways. It was carried out in a mini-fixed bed reactor in which the feeding gas is supplied successively. The experiment result has showed: although adding Ni and Al₂O₃ can increase the activity of the catalyst, but selectivity of the catalyst decreased. Rotating evaporating dryness is suitable to prepare the precursors of the catalyst, and the drying temperature should be 50℃. the process of calcination of catalysts doesn't have to do with the kind of the safity of N2 is 1mL/min, the catalyst prepared by twice calcination processes is the best, but the stability of eguard gas, the opening calcination ambience is better than the close ambience, the appropriate flow velocwhich is not good in the test enduring 210 hours, in which the conversion of propane increased from 48.5% to 61.7%, and the yield of acrylic acid increased from 25.1% to 31.2%. The results of the study of catalytic technology has showed: comparaed with the reactor made of stainless steel , the reactor made of quartz is suitable for oxygenation of propane to prepare acrylic acid, and the best vacuum velocity is 600h^-1. The characteristics by XRD and BET of the catalyst has showed that Al₂O₃ changed the crystal fabric of the catalyst and increased the specific surface of the catalyst, besides, the phase of Te_0.33MO₃ played an important role in the formation of AA.