Simulation study of membrane distillation regenerator based on reduced pressure air gap

Abstract

To reduce the regeneration energy consumption and improve the regeneration effect of liquid desiccant in membrane-based liquid desiccant air conditioning (M-LDAC), this paper combines the widely used Vacuum Membrane Distillation (VMD) and Air Gap Membrane Distillation (AGMD) methods, and innovatively proposes a reduced pressure air gap membrane distillation regeneration system, and applies the control variable method to simulate the influencing factors (desiccant temperature, flow rate, and air gap side vacuum) in the system. The results showed that the desiccant temperature and air-gap side vacuum had more influence on the system membrane flux than the flow rate, and the simulation showed that there was an optimal range of vacuum, and the membrane flux reached 12.55 kg/(m2·h) when the desiccant temperature was 90 °C, the flow rate was 0.2 m/s, and the vacuum was 40 Kpa, which increased the membrane flux by 14.8% compared with 10 Kpa. The analysis proves that the use of vacuum on the air gap side can effectively improve the membrane flux, which provides a reference for the optimal design of future liquid desiccant regenerator modules.