Opportunities for utilizing waste cooking oil in crude to petrochemical process: Novel process design, optimal strategy, techno-economic analysis and life cycle society-environment assessment

The efficient utilization of waste cooking oil (WCO) in petrochemical and high-quality gasoline production could reduce food safety issues and boost the new energy industry's sustainable development. The co-processing of WCO, vacuum gas oil, and light cycle oil (LCO) by the fluid catalytic cracking unit could achieve process integration, which exhibits promising economic prospects for manufacturing large amounts of low-cost petrochemicals. Herein, we proposed a novel process, i.e., hierarchical LCO hydrotreating combined with two-stage riser catalytic cracking processes (HTMP-plus). Based on industrial test data, the process model of HTMP-plus was first developed on the Aspen HYSYS Petroleum Refining platform and optimized operating parameters were conducted. In this novel process, lighter LCO fractions were directly recycled to the second riser reactor, and heavier LCO fractions were fed into the selective hydrotreating unit. This strategy intensified the conversion of WCO and LCO, reduced hydrogen consumption, and improved the economic benefit. Furthermore, the life cycle society-environment evaluation was performed. Compared with the conventional HTMP process, the HTMP-plus process could produce 5% more propylene and high-quality gasoline for every ton of mixed feedstock and provide up to a 31% increase in net present value. Moreover, the HTMP-plus process consumes approximately 5% less non-renewable energy and discharges 2% less CO2 equivalent and 16% less wastewater based on one-million-USD dollars total output value.