The effect produced by the degree of hydrotreatment and the content of heteroatoms in an initial cracking feedstock on its conversion, the distribution of cracking products, and the composition of regeneration gases was studied. The four types of feedstocks, such as a hydrocracking residue, hydrotreated vacuum gas oil, nonhydrotreated vacuum gas oil, and a mixed feedstock containing 20% of mazut and 80% of nonhydrotreated vacuum gas oil, were investigated. To each type of feedstock, indole, quinoline, and benzothiophene were added. It was established that, when the depth of feedstock hydroskimming decreases, the conversion and the yield of cracking products (gasoline and light olefines) become lower, and the concentrations of sulfur nitrogen oxides in regeneration gases grow. In this paper, the influence of sulfur- and nitrogen-containing compounds in a catalytic cracking feedstock on the yield of products and the composition of regeneration gases is shown. Sulfur- and nitrogen-containing compounds in a cracking feedstock decrease the conversion and the yield of target products, and the presence of basic nitrogen compounds in a feedstock leads to the formation of a large quantity of nitrogen oxides during the regeneration of a given catalyst.
Kobzar’ et al. (Wed,) studied this question.