Home – Home – Jornals – Chemistry for Sustainable Development 2022 number 2

The catalytic properties of ZSM-5 type zeolites modified with copper, zirconium and boron in the process of obtaining high-octane gasoline from the straight-run gasoline fraction of gas condensate have been studied in a flow-through installation at atmospheric pressure without hydrogen within the temperature range 350-430 °C. Cracking and aromatization of hydrocarbons mainly take place on non-modified HZSM-5 zeolite; with an increase in reaction temperature from 350 to 430 °C on HZSM-5, an increase in the content of aromatic hydrocarbons (from 10.8 to 16.9 mass %) and a decrease in the yield of liquid hydrocarbons (from 68.6 to 60.8 mass %) is observed. Modification of HZSM-5 zeolite with copper significantly changes the content of high-octane components in the catalyzate. An increase in copper concentration in HZSM-5 up to 2.0 mass % leads to an increase in the ability of the catalyst to provide isomerization and aromatization. At the optimum temperature (380 °C), the content of isoparaffinic and aromatic hydrocarbons in the catalyzate increases up to 36.8 and 24.6 mass %, respectively. An increase in the concentration of copper in HZSM-5 up to 3.0 mass % promotes an increase in the aromatization ability of the catalyst. Modification of the catalyst 2 % Cu/HZSM-5 with boron in the amount of 0.5-1.0 mass % has a small effect on its isomerization and aromatization properties, but significantly increases the yield of liquid products. It is found that the modification of the catalyst 2.0 % Cu-1.0 % B/HZSM-5 with zirconium in the amount of 0.5-1.5 mass % significantly increases the content of isoparaffinic hydrocarbons in the catalyzate (42.1-43.5 mass %). The highest activity is exhibited by the bimetallic catalyst consisting of 1.0 % Zr-2.0 % Cu-1.0 % B/HZSM-5, which allows obtaining the gasoline fraction with 88-94 octane number according to the research method. The addition of boron in the amount of 1.0 mass %, followed by the introduction of zirconium and copper, makes it possible to increase the duration of catalyst operation by up to 200 h. With respect to the content of isoparaffinic and aromatic hydrocarbons and benzene, the gasoline fraction corresponds to the Euro-4 and Euro-5 class. The possibility of refining low-octane straight-run gasoline fractions in the presence of a bimetallic catalyst under unconventional conditions without hydrogen supply to the reaction zone at atmospheric pressure is demonstrated.