Effect of Phosphorus Modification of Zeolites Y and ZSM-5 on the Cracking of Hydrotreated Vacuum Gas Oil and a Vacuum Gas Oil–Sunflower Oil Mixture

Abstract

The effect of the preliminary impregnation of zeolites HREY and HZSM-5 with ammonium phosphate before introducing them into the composition of dual-zeolite catalysts has been studied. It has been found that the modification leads to a change in the main textural characteristics of the zeolites. Both the specific surface area and the meso- and micropore volume of the zeolites decrease. The total acidity of HREY and HZSM-5 and the number of strong acid sites in them also decrease. Tests on the conversion of hydrotreated vacuum gas oil and a vacuum gas oil–sunflower oil mixture under catalytic cracking conditions have shown that the modification of the zeolites leads to an increase in the total yield of the propane–propylene and butane–butylene fractions with a high olefin content in them, even with a decrease in the feedstock conversion.