Internal-pressure-type vacuum membrane distillation concentration method of ethylene glycol solution

The invention discloses an internal-pressure-type vacuum membrane distillation concentration method of an ethylene glycol solution. Concentration and purification of the ethylene glycol solution in a process of preparing ethylene glycol from oxirane through a hydration method are carried out through the internal-pressure-type vacuum membrane distillation coupled with a rectification technology. The method comprises following steps: (1) pumping the ethylene glycol water solution at about 85-100 DEG C into a raw water tank; (2) pumping the ethylene glycol water solution in the raw water tank to a tube pass of a hollow fiber membrane assembly at a specific membrane surface flow rate through a material feeding pump; and (3) vacuumizing a permeation side, namely, a shell pass, of a hollow fiber membrane assembly, so that condensable gas is condensed through a condenser at the permeation side to form water while a concentrated ethylene glycol solution in the tube pass is fed back to the raw water tank for circulating concentration. Compared with multiple-effect evaporation, the method is less in equipment investment, is high in treatment efficiency, is low in operation temperature and operation pressure and is low in energy consumption.