Research and Application of Modified ZSM-5 for the Process of Alkylation of Oil Distillate Fractions

Abstract

In the oil distillate fraction alkylation process, a modified Zr zeolite ZSM-5 was obtained and studied. The modification was executed using a method that impregnated ZSM-5 with a 5% solution of ZrOCl<sub>2</sub>∙6H<sub>2</sub>O. X-ray diffraction studies were conducted on zeolite ZSM-5, zirconyl chloride modifier ZrOCl<sub>2</sub>∙6H<sub>2</sub>O, and modified zeolite ZSM-5-ZrO<sub>2</sub>, which was calcined at temperatures of 200, 400, and 550°C. The results revealed that the phase composition of modified ZSM-5-ZrO<sub>2</sub> zeolite samples varied depending on the calcination temperature. It was determined that only at a temperature of 550°C did the modified ZSM-5 catalyst contain three phases belonging to ZrSi<sub>24</sub>O<sub>50</sub>, ZrO<sub>2</sub>, and ZSM-5. The emergence of the ZrO<sub>2</sub> phase occurred at a calcination temperature of 550°C. An increase in temperature from 200 to 550°C facilitated the transition of the amorphous phase to the crystalline phase. The crystal structure of the ZSM-5-ZrO<sub>2</sub> catalyst, calcined at 550°C, contributed to a rise in its activity. Consequently, during alkylation with catalytic cracking gases, the viscosity-temperature properties of the T-30 turbine oil distillate fraction significantly improved (the viscosity index increased from 49.9 to 137). An increase in zeolite ZSM-5 activity was demonstratd due to the introduction of zirconium and an elevated calcination temperature to 550°C.