Modified Polymetallic Zeolite-Based Catalysts for Hydroprocessing Diesel Oil Fraction and Tetradecane

According to international standards, motor fuels require limits on the content of sulfur, benzene, aromatic and olefinic hydrocarbons.Achieving these standards requires the development of new, active, and selective catalysts alongside advancement in technologies for deep hydrotreating and hydroprocessing.Therefore, this study aimed to investigate tetradecane and diesel oil fraction hydroprocessing using modified zeolite-based Ni(Co)-Mo(W)/Al2O3-ZSM-5 catalysts under varying processing conditions.The novelty is attributed to the synthesis of new catalysts based on ZSM-5 type zeolite, modified with metals Ni(Co)-Mo(W) and active additives of rare earth metals and phosphorus.The results showed that after hydrotreating diesel oil fraction on KT-3 catalyst, the pour point and sulfur level decreased from -27 to -57°C and 0.141 to 0.059% respectively, while the yield of the liquid phase was 92.2%.The lowest residual sulfur content (0.005%) was observed on KT-4 catalyst at 400°C.Based on electron microscopic examinations, modified zeolite-based catalysts were distributed in a highly dispersed manner, and the metal components in the active phase were primarily in the oxidized state, generating associate clusters on the surface.The dispersion, structure, and state were influenced by the characteristics of catalyst components.In conclusion, modified zeolite-based catalysts had multifunctional properties, facilitating hydrocracking, hydroisomerization, hydrodesulfurization, and dehydrogenation reactions concurrently.