Influence of drying conditions on the properties of vanadium-sulfate catalysts

The process of drying vanadium sulphate catalysts (VSC) is accompanied by a change in the coagulation structure of the freshly shaped extrusions into the condensation structure of the air-dried green products. This process depends on the drying conditions, and in some cases determines the quality of the final products. The drying conditions for catalyst blanks was investigated using VSC bodies containing diatomite, white carbon, or silica gel. The temporary bond consisted of aqueous solutions of carboxymethyl cellulose, polyethylene oxide, and polyethylene glycol esters of mono- and dialkylphenyls. The dispersion medium also contained alkaline sulphates. The drying kinetics were studied. The quality of the dried material largely depends on the drying temperature and the type of temporary bond, and to a lesser degree on the nature of the carrier. For the same specific surface, the highest strength is shown by greenware and calcined catalysts shaped from bodies containing carboxymethyl cellulose. The quality of the finished products and the yield of acceptable goods can be increased by shaping the blanks for catalyst bodies with the use of CMC, and drying at 110-125 C. 3 refs.