This research studies the problems of the traditional heat exchanger of MRU system that has low heat exchange efficiency, occupies large plot size and is prone to scaling. The liquid-solid two-phase flow in detachable all-welded plate heat exchanger and spiral plate heat exchanger was numerically simulated, focusing on the movement and distribution of salt particles in the heat exchanger, and the possible particle deposition and even blockage of the heat exchanger were predicted. The simulation results show that the distribution of MEG circulating fluid and salt particles in counter current flow passage of the all-welded plate heat exchanger is uneven due to the disturbance caused by grooves (rib) and corrugated boss-type structure. The flow field in the spiral plate heat exchanger is smooth without the turbulent flow and the sudden change in localized flow area. The salt particle movement is in uniform distribution, which facilitates the discharge of lean MEG from heat exchanger. It is concluded that spiral plate heat exchanger is more suitable and effective in MRU system. The results can provide reference for selection and parameter design of recirculation heater in MRU system.