Double-impregnation method of producing a pelleted catalyst

Claim 1

IN THE PREPARATION OF IMPREGNATED CATALYSTS IN PELLETED FORM CONTAINING HIGH CONCENTRATION OF CATALYTICALLY ACTIVE HEAVY METAL PROMOTER IN COMBINATION WITH A RELATIVELY INERT CARRIER MATERIAL, THE COMBINATION OF STEPS WHICH COMPRISES DISSOLVING THE DESIRED AMOUNT OF A COMPOUND OF THE HEAVY METAL PROMOTER DECOMPOSABLE TO THE OXIDE BY HEATING IN TWO PORTIONS (A AND B) OF A SOLVENT IN SUCH A MANNER THAT PORTION A CONTAINS FROM ABOUT 8 TO ABOUT 12 PARTS OF THE HEAVY METAL PROMOTER PER 100 PARTS OF THE RELATIVELY INERT CARRIER AND PORTION B CONTAINS THE REMAINING AMOUNT OF SAID HEAVY METAL PROMOTER, IMPREGNATING THE RELATIVELY INERT CARRIER WITH THE SAID PORTION B, DRYING AND CALCINING THE RESULTING IMPREGNATED CARRIER AT A TEMPERATURE SUFFICIENT TO DECOMPOSE THE IMPREGNANT COMPOUND, IMPREGNATING THE RESULTING CALCINED MATERIAL WITH SAID PORTION A, DRYING THE RESULTING IMPREGNATED MATERIAL AT A TEMPERATURE BELOW THAT CAUSING DECOMPOSITION OF THE IMPREGNANT COMPOUND, PRESSING THE RESULTING MATERIAL INTO PELLETS, AND CALCINING SAID PELLETS AT A TEMPERATURE SUFFICIENT TO DECOMPOSE THE IMPREGNANT COMPOUND.