Enhancing the Conversion of Polycyclic Aromatic Hydrocarbons from Naphthenic Heavy Oil: Novel Process Design, Comparative Techno-Economic Analysis, and Life Cycle Assessment

Enhancing the deep processing of naphthenic heavy oil and selective hydrogenated saturation combined with ring opening of polycyclic aromatic hydrocarbons (PAHs) have extremely important industrial and economic significance. A novel process, termed deep hydrotreating coupling with two-stage-riser catalytic cracking for maximizing propylene (DHTMP), is proposed, simulated, and optimized for converting PAHs rich in heavy oil and light cycle oil (LCO) to benzene, toluene, and xylene. The unique feature of the DHTMP process is integrating LCO deep hydrotreating with a two-stage-riser for maximizing propylene production. The key process indexes for limiting the efficient conversion of PAHs are first proposed and quantified. Based on the optimized process parameters, the techno-economic analysis and life cycle assessment are employed to identify the advantages of the DHTMP process over the residue fluid catalytic cracking and deep catalytic cracking processes. The DHTMP process has not only realized efficient full conversion of LCO but also shows the highest mass yields of high-value products and petrochemicals. Furthermore, the DHTMP process exhibits both favorable performances from the economic-environment level. The DHTMP process has both the highest net present value, 2.16 x 10(9) ChinaYuan (CNY), and internal rate of return, 21.56%. As for environmental performance, the DHTMP process leads to the least primary energy consumption, and the greenhouse gas emissions reduce 66.53 t CO2 equivalents per million CNY output value compared with the deep catalytic cracking process.