Experimental study on the concentration of ethylene glycol aqueous solution by metal powder sintered porous capillary wicks

In industry, the ethylene glycol concentration is realized by flashing and distillation and a series of processes. These processes with high energy consumption are complicated. To solve this problem, a method for concentrating ethylene glycol aqueous solution with metal powder sintered capillary wick is proposed. The capillary wick with length 50 mm, outer diameter 30 mm and inner diameter 10 mm sintered by copper powder is used as an evaporator for ethylene glycol solution in this study. The effects of inlet flow rate, heating temperature, inlet concentration, as well as the pore size of the capillary wicks on the concentration of ethylene glycol are all analyzed experimentally. It is found that the ethylene glycol solution can be concentrated from the mass fraction of 10% at inlet to 16% at outlet through the capillary wick, which indicates that the concentration method proposed in this paper is feasible. Moreover, the evaporated water is generally positively correlated with inlet flow rate and evaporation temperature within a certain range, however, the evaporation will not increase when the inlet flow rate and heating temperature reaches a certain level due to the permeation and evaporation limitation effect. Increasing the inlet concentration reduces the volume of the condensate, but the corresponding increase in outlet concentration is not noticeable. It is also found experimentally that the capillary wick sintered with particles with 56.3 μm diameter has the best concentration performance for the ethylene glycol solution. The concentration method proposed by this study is expected to be helpful for the dehydration of organic solvents or the separation of binary non-azeotropic liquid mixtures in industrial production.