Steam catalytic cracking of vacuum gas oil: Effect of co-feeding naphtha or gas condensate on light olefins yield

Abstract

Herein, we have investigated the steam catalytic cracking of heavy VGO (HVGO) blends with naphtha (NAPH) and gas condensates (GCON) in a microflow fixed-bed reactor using synthesized nano-ZSM-5 catalyst for increased light olefins yield. The co-feeding of HVGO with NAPH in the steam cracking reaction increased HVGO conversion from 38.2 % to 65.3 %, and slightly decreased the coke yield. Ethylene and propylene yield increased from 10.2 % and 9. 8 % in HVGO to 15.0 % and 13.4 % in the HVGO+20 %NAPH respectively. The co-feeding of HVGO with GCON in the steam cracking reaction increased HVGO conversion from 38.2 % to 47.5 %, however, lower yield of light olefins was recorded. The catalytic cracking of HVGO with NAPH over synthesized nano-ZSM-5 zeolite resulted in higher conversion and light olefins yield. This has been ascribed to the available acid sites and shape selectivity of the nano-zeolite that favors high yield of light olefins. The HVGO+20 %GCON conversion increased to 68.6 % during catalytic cracking over nano-ZSM-5 zeolite, and the light olefins increased from 33.2 % to 41.1 %. The effect of steam/oil ratio on the catalytic cracking reactions of HVGO+20 %NAPH and HVGO+20 %GCON for steam/oil ratio 0–2 showed that higher conversion and light olefins yield were achieved at the steam/oil ratio of 2.