Composition of emissions of sulfur and nitrogen oxides depending on the depth of hydrotreatment of FCC feedstock

The study of the effect of the composition of the feedstock cracking on its conversion, distribution of cracking products and composition of regeneration gases. Four types of feedstocks were studied: hydrocracking residue, hydrotreated vacuum gas oil, non-hydrotreated vacuum gas oil and mixed feedstock containing 20 wt. % of fuel oil and 80 wt. % of non-hydrotreated vacuum gas oil. Indole, quinoline and benzothiophene were additionally introduced into each type of feedstock, as well as benzothiophene and indole simultaneously. It was found that with an increase in the fractional composition of the feedstock, a decrease in conversion and the yield of cracking products (gasoline and light olefins) occurs. An increase in the concentration of sulfur and nitrogen oxides in the regeneration gases is also observed.