A performance optimization method of multi-phase extraction for soil remediation based on multi-loops coordinated control

Soil pollution has been a global environmental problem. Multi-phase extraction (MPE) is one of the most widely used soil remediation technologies. However, this technology has the problems of low efficiency and high energy consumption, which seriously limit the progress of soil remediation work. In this study, with the aim to improve soil remediation efficiency and save energy, a performance optimization method based on multi-loops coordinated control for MPE was proposed. The performance optimization method combined process parameters optimization and control strategy optimization. In the process parameters optimization, based on the established multiphase flow migration model and MPE system model, the optimal parameters of MPE were obtained. In the latter, the multi-loops coordinated control strategy was used to balance the system's perturbations and control the concentration of pollutants in the extraction pipeline, the extraction vacuum, the adsorption pressure and inlet flow rate of the activated carbon filter. To verify the effectiveness of the optimization method, it was compared with the actual engineering operation strategy, i.e., single loop separation control. Under the same conditions, the optimized method can improve efficiency by 15.4% and save 12.5% energy. Thus, this study can be used as an advantageous tool for the design of MPE.