Hydrogenation and TMP Coupling Process: Novel Process Design, Techno-Economic Analysis, Environmental Assessment and Thermo-Economic Optimization

The production of high-quality gasoline and light olefins harbors tremendous industrial and economic significance. In this paper, a novel process is proposed for converting inferior light cycle oil (LCO) into propylene and ethylene, as well as the high-octane-number gasoline with rich BTX contents. The unique feature for the novel process is the integration of LCO selective hydrogenation unit with two-stage riser catalytic cracking. For comparative techno-economic and environmental analyses, typical two-stage riser catalytic cracking for maximizing the propylene (TMP) process and conventional residue fluid catalytic cracking (RFCC) process models are developed. Based on the detailed process modeling and simulation results, techno-economic evaluation and environmental assessment have been performed. It is found that the novel process, coupled hydrogenation and TMP process, has a favorable impact on both the economic and environmental performances. The HTMP process has the highest net present value that means 2.13 times of TMP and 4.94 times of RFCC process, and reduces 15.26 t CO2 equivalents per million dollars output value compared with the TMP process. Moreover, we conduct the thermo-economic optimization for the HTMP process based on the exergy analysis. The result shows that full scale hydrogenation and recycling of hydro-LCO and increasing of the second riser outlet temperature could significantly increase the profitability of this novel process.