Crude oil conversion to chemicals over green synthesized ZSM-5 zeolite

Abstract

The study reports the conversion of crude oil to basic chemicals over a template-free green synthesis of ZSM-5(40) zeolite using halloysite (HAL) and bolus alpha (BA) as silica and alumina precursors. The Z(40)HAL and Z(40)BA exhibited hierarchical pores with high surface area of 248 m2/g and 257 m2/g, respectively. The addition of soft template during the synthesis of Z(40)BA forms a Z(40)BAT zeolite with lower surface area. The synthesized zeolites were impregnated with 2wt%Mn and tested for the steam catalytic cracking of crude oil to light olefins and aromatics catalysts at 675 °C in a fixed-bed reactor. Maximum light olefins (C2=-C4=) yield (47 wt%) and total aromatics (14.7 wt%) were attained over 2Mn/Z(40)HAL catalyst. The conversion of crude oil (68.4%) is attributed to hierarchical pores and the presence of large weak and strong acid sites in the 2Mn/Z(40)HAL zeolite. Moreover, due to the high reaction temperature, some effects of thermal cracking such as protolytic cracking reactions with high ethylene yield (22%) were introduced. The addition of 1% phosphorus and 1%Mn to Z(40)HAL resulted in lower catalytic cracking activity. Similarly, the 2Mn/Z(40)BAT performed slightly lower than the template-free 2Mn/Z(40)BA additive. The experimental results demonstrate the technical feasibility of template-free green synthesis of ZSM-5 zeolite in the conversion of crude oil to basic chemicals.