Abstract: A purification method for separating and purifying an organic solvent from a liquid mixture of an organic solvent and water, the organic solvent having a boiling point of more than 100° C. at 1 atm, includes the steps of: passing the liquid mixture through a first ion exchange device; supplying the liquid mixture discharged from the first ion exchange device to a pervaporation device to selectively separate water component; supplying the organic solvent recovered from the concentration side of the pervaporation device to an evaporator to obtain a purified organic solvent; and passing, through the second ion exchange device, a portion of liquid containing the organic solvent and flowing at a first position subsequent to the first ion exchange device. The liquid discharged from the second ion exchange device is returned to a second position which is at a preceding stage of the pervaporation device.

Abstract: An organic solvent purification system that separates an organic solvent having a boiling point of more than 100° C. at 1 atm, such as N-methyl-2-pyrrolidone (NMP), from a liquid mixture containing the organic solvent and water and purifies the organic solvent includes: a heater that heats the liquid mixture; a pervaporation apparatus that includes a pervaporation membrane, and is provided at subsequent position of the heater, the pervaporation apparatus separating the organic solvent from the water; a vacuum evaporator to which the organic solvent collected from a concentration side of the pervaporation apparatus is supplied; and piping that supplies the heater with the organic solvent vaporized in the vacuum evaporator as a heat source of the heater. The heater heats the liquid mixture using concentration heat of the organic solvent vaporized by the vacuum evaporator.

Abstract: An organic solvent purification system that separates an organic solvent having a boiling point of more than 100° C. at 1 atm, such as N-methyl-2-pyrrolidone (NMP), from a liquid mixture containing the organic solvent and water and purifies the organic solvent includes: a heater that heats the liquid mixture; a pervaporation apparatus that includes a pervaporation membrane, and is provided at subsequent position of the heater, the pervaporation apparatus separating the organic solvent from the water; a vacuum evaporator to which the organic solvent collected from a concentration side of the pervaporation apparatus is supplied; and piping that supplies the heater with the organic solvent vaporized in the vacuum evaporator as a heat source of the heater. The heater heats the liquid mixture using concentration heat of the organic solvent vaporized by the vacuum evaporator.