Effects of the depth of hydro desulfurization of raw materials on the yields of catalytic cracking products

The article is devoted to the problem of complex processing of oil feedstock and increasing the output of light petroleum products, in particular, catalytic cracking gasoline. Currently, the oil refining industry of Kazakhstan is faced with the task of complex processing of hydrocarbon raw materials, increasing the depth of processing and output of light petroleum products. In this connection it is urgent to solve the problem of lack of raw materials for oil refineries of the Republic of Kazakhstan. The complexity of solving the problem of processing residues of oils, fuel oil and intermediates of secondary processes lies in the fact that they contain a large amount of various sulfur compounds. This problem concerns not only domestic refineries, for example, oil from Uzbekistan fields contains a relatively large amount of SO2 compounds, which in turn contains about 1.28% sulphur. The high content of sulfur compounds in oil not only negatively affects the quality and environmental friendliness of manufactured products, but also reduces the service life of equipment and oil refineries. In this regard, the preparation and hydrodesulfurization of raw materials is one of the main issues of intensifying the process of catalytic cracking of petroleum raw materials of "PKOP" LLP. The issues of possibility of modernisation of catalytic cracking process units by including the process of hydrodesulphurisation of feedstock in order to improve the quality and yield of light products when using fuel oil and secondary intermediates having a large volume of various sulphur compounds in their composition have been considered by the authors. To evaluate the influence of the depth of hydrodesulfurisation of feedstock on the yields and composition of catalytic cracking products, the cracking of crude and hydrotreated hydrogenated vacuum gas oil mixed with fuel oil was carried out on a laboratory unit. The experiments were carried out on a fluidised catalyst bed at mass feed rates of 2h-1 and 4h-1, catalyst to feed ratio of 3:1 and temperature equal to 5100 C. The analysis of the experimental data obtained showed that preliminary hydrotreating of a mixture of vacuum gas oil and sulfur fuel oil followed by catalytic cracking increases the depth of oil refining and helps to increase the yield of catalytic distillate, improves its quality, which ultimately leads to a decrease in environmental pollution with sulfur compounds.