Study on Acid-Base Coupled Catalytic Pyrolysis of Heavy Crude Oil to Light Olefins and Aromatics by Py-Gc/Ms and Fixed Bed Reactor

Direct catalytic cracking of heavy crude oil has gained attention as an alternative and cheapest method of producing raw materials for the petrochemical industry. The Py-GC/MS technique was used to study the effects of calcium aluminate base catalysts and ZSM-5 acid zeolites on heavy crude oil conversion. The results showed that ZSM-5 with a Si/Al ratio of 40 (40Z) outperformed zeolites with Si/Al ratios of 80 and 200, with a maximum selectivity of 65% for light olefins and BTX (benzene, toluene and xylene). Among all base catalysts studied, calcium aluminate (CaAl-3) had the highest selectivity of 23% of C2-C4 olefins and BTX. The “Mix” model outperformed the “Base + Acid” or “Acid + Base” models in terms of minimizing hydrogen transfer reactions and maximizing the yield and selectivity of light olefins. The 30 C catalyst (30%CaAl-3 +70%40Z) exhibited significant co-effect of basic and acidic catalysis, with maximum light olefin selectivity and total olefinicity of 72% and 81%, respectively. The results of the present work showed that acid-base coupled catalytic pyrolysis was a viable approach for improving the yield of light olefins and aromatics.