Study On Preparing And Performance Of MoVTeNb Catalysts With Different Telluric Compounds

MoVTeNbO catalysts is one of the most potential catalysts at present time, which have good performance in the catalytic oxidation of propane to acrylic acid, and has been studied extensively in recent years.In order to improve acrylic acid yield and stability of Mo-V-Te-Nb-O mixed metal-oxide catalysts, the influence of different telluric compounds on catalytic performance was studied emphatically in this paper. The alkaline additives, ultrasonic treatment and pre-calcination in air were introduced during the preparation of catalysts which made by different telluric compounds. The characterization analysis of deactivated catalyst was made by ICP and XRD, and some explorative research on regeneration treatment was carried on. The performance of Mo-V-Te-Nb-O mixed metal- oxide catalysts were evaluated in a fixed bed micro-reactor, which the raw gas was feeding continuously, and the influence of those factors in catalysts preparation were obtained.The results showed that, adding alkaline additives and ultrasonic treatment could not improve the performance of catalysts prepared by telluric acid, while these operations were beneficial to the catalysts prepared by insoluble telluric compounds. But compared with the catalysts prepared by telluric acid, the improved performance of the later were still worse; the performance of catalysts prepared by different telluric compounds were improved to different extent when the operation of pre-calcination in air was introduced during their preparation; telluric acid was still the best telluric compounds to prepare MoVTeNbOx catalysts which had excellent performance in the catalytic oxidation of propane to acrylic acid. The effect of regeneration treatment with Te compound was the best, the AA yield was risen from 2.15% to 6.21%, but it was also much worse than which of the active catalyst. The reaction conditions of selective catalytic oxidation of propane were also studied. As shown by the experiment results, the proper reaction conditions were chosen as follows: reaction temperature-400℃; total space velocity-1100h-1; ratio of reacting gas-C30/N2/O2=4.19/42.43/8.38; water content-47%. Under the fore-mentioned condition, the conversion of propane reached 46.41%, and the yield of AA reached 24.11%.