Optimization of Slurry Loop Reactors by Understanding the Complex Mesoscale Structure of Liquid–Solid Flow

Abstract

Slurry loop reactors have been extensively used in chemical industry, for example, ethylene copolymerization. A classical engineering problem is the timely removal of reaction heat which would otherwise cause particle swelling and aggregation, and thus reactor fouling, operation instability, or even blockage, imposing a high safety risk in production. Lack of knowledge on the mesoscale information of particle swelling and aggregation poses great challenge on the prediction of the macroscale behavior. A swelling-dependent two-fluid model was developed and applied for reactor optimization in this work to account for the evolution of mesoscale structures. The simulation resolves the particle aggregation and plug accumulation in the upstream of the pump and the upper horizontal pipe, revealing the fundamental of reactor blockage. The mesoscale structure, when developing to a certain extent, can cause a sharp increase of pump power consumption. This structure can be characterized by the growth and threshold of the plug volume. Based on this mesoscale understanding, a reactor optimization scheme was heuristically proposed to minimize or eliminate the plug regions by employing two pumps and two cycles.