The effect of recycle stream on slurry-phase hydrocracking of vacuum residue: An experimental and modeling approach

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) 2024, 129(0), , pp.555-567
• Main Authors: Pham, Hung Hai, Lim, Suk Hyun, Go, Kang Seok, Nho, Nam Sun, Kwon, Eun Hee, Kim, Kwang Ho, Ryu, Ho-Jung
• Format: Article
• Language: English
• Subjects: Heavy oil upgrading; Kinetic modeling; Once-through mode; Optimization; Recycle mode; Slurry-phase hydrocracking; 화학공학
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2023.09.014

[Display omitted] •Unconverted residue in ROM was found to become more refractory.•A slurry-phase HCK kinetic model was modified to incorporate the recycling effects.•A dynamic Simulink model accurately predicted the process performance in ROM.•An operational stability index was proposed to ensure stable ROM operation.•Optimal operating conditions were determined to address multiple process objectives. The effect of the recycle stream on slurry-phase hydrocracking (HCK) of vacuum residue was examined using a continuous bench-scale unit with the aim of attaining process optimization. This was achieved through a model-based approach that links experimental investigations, kinetic modeling, and model-based optimization. The experiments were conducted at various reaction temperatures, liquid hourly space velocity of fresh feed (LHSVFF) and recycle ratios at a pressure of 160 bar, with the fresh feed containing 1000 wt. ppm of molybdenum. The HCK kinetic model was modified to incorporate the recycling effects and accurately predict the experimental data. The adapted model confirmed that the unconverted residue in recycle operating mode (ROM) became more refractory. By implementing the modified kinetic model in a dynamic Simulink model, the prediction accuracy of RES conversions and product yields can be improved by up to 25.1 wt.% in the case of the lowest conversion. A sensitivity analysis using the dynamic model showed that the temperature exerted a greater impact on the RES conversion and recycle ratio in ROM. An operational stability index was also proposed to prevent operation failure in ROM. Finally, an optimal operating condition from the parametric study was found to meet several process goals simultaneously.