Study on Gas-Liquid Sulfonation Reaction Under Annular Flow Pattern in Micro-Reactor: Mechanism, Model and Process Optimization

Abstract

Micro-sulfonation is a new sulfonation method with great development potential. The gas-liquid micro-sulfonation are safe, efficient and low-cost, however, limited by the research progress and application scope of micro-reactors, the development of gas-liquid micro-sulfonation technique is far from enough. The gas-liquid sulfonation reaction process under annular flow pattern in micro-reactor is experimentally studied in this paper. The maximum MESA yield under the experimental conditions in this study achieves 88.385%, which is obviously higher than that (64.1% for gas-liquid sulfonation and 76.82% for liquid-liquid sulfonation) in conventional reactors and should be higher if the micro-reactor structure or operating conditions being further optimized. Based on the analyses of experimental results, the effect mechanisms of mass transfer and reaction on the gas-liquid micro-sulfonation efficiency are explored, and the sulfonation efficiency models and pressure drop model of four micro-reactors are established by dimensional analysis method. On account of both the mass transfer characteristics of gas-liquid two-phase flow and the high-viscosity of sulfonation products, enhancing the local disturbance of liquid phase can significantly improve the reaction efficiency. Finally, the two-phase flow rate conditions are optimized to make the sulfonation simultaneously achieve the objectives of high product yield and low fluid pressure drop using the improved NSGA-II algorithm.

Keywords: Gas-liquid micro-sulfonation, Annular flow, Transfer mechanism and reaction model, Multi-objective optimization, High viscosity