Превращение прямогонной бензиновой фракции и газоконденсата на биметаллических ка-тализаторах на основе цеолита ZSM-5

Abstract

Acidic and catalytic properties of bimetallic catalysts based on ZSM-5 zeolite modified with copper, cobalt and boron in the conversion of straight-run gasoline fraction of gas condensate were studied in a flow-through unit at atmospheric pressure, in the absence of hydrogen in the temperature range 350-4300C. It has been established that the introduction of modifiers (Cu, Co, B) into the zeolite leads to a sig-nificant decrease in the strength and concentration of acid sites. An increase in the copper concen-tration in the zeolite to 3.0 wt.% leads to a decrease in the concentration of strong acid sites from 542 to 332 mmol/g. The introduction of 2% Cu/HZSM-5 into the catalyst composition of the second modifier Co in an amount of up to 1.5 wt.% reduces the concentration of strong acid sites to 242 mmol/g. With the additional modification of the bimetallic catalyst 1.0% Co 2% Cu/HZSM-5 with boron in an amount of 0.5-1.5 wt.%, the concentration of strong acid sites further decreases to 112-198 mmol/g. On unmodified zeolite HZSM-5, which has strong acid sites, cracking and aromatization of hydro-carbons mainly take place. Isomerization of n-paraffin hydrocarbons that make up the gas conden-sate is not significant. As a result of the modification of HZSM-5 with copper in the amount of 1.0-3.0 wt. %.There is a significant increase in the catalyzate content of high-octane components: iso-paraffinic and aromatic hydrocarbons. Modification of the catalyst with 2% Cu/HZSM-5 Co in an amount of 0.5-1.0 wt.% increases its isomerizing activity, and additional modification with boron (0.5-1.5 wt.%) leads to an increase in the yield of liquid products. The relationship between the acid-ic and catalytic properties of modified catalysts has been established. The effect of increasing the isomerizing and aromatizing activity of the modified catalysts is associated with the nature, concen-tration of the modifier, and the ratio of weak and strong acid sites. The isomerizing and aromatizing activity of the catalyst is controlled by the nature and concentration of the modifier. The bimetallic catalyst 1.0% Co 2.0 Cu% 1.0% B/HZSМ-5 exhibits the highest activity in upgrading straight-run gasoline fraction of gas condensate, which makes it possible to obtain a gasoline component with an octane number of 86.5 according to IM at 3800C and a yield of 77.8 wt.%.