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

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.