METHOD FOR CONCENTRATING AND RECOVERING AQUEOUS SOLUTION OF A SURFACTANT

摘要

A method for concentrating and recovering an aqueous solution of a surfactant is provided whereby an aqueous solution of a surfactant having a high concentration of the surfactant can be efficiently and easily obtained by evaporating and concentrating the aqueous solution of a surfactant while suppressing foam formation. In said method, the aqueous solution of a surfactant comprising a gasifiable surfactant and a gasifiable aqueous solvent is evaporated and concentrated, and the surfactant is concentrated to a high degree. The aqueous solution of a surfactant is held inside an evaporator (12), the temperature of the aqueous solution of a surfactant inside the evaporator (12) is set to a temperature lower than the boiling point of the aqueous solvent under pressure in the evaporator (12), a portion of the aqueous solution of a surfactant is extracted from the evaporator (12), all of the surfactant and the aqueous solvent therein are superheated by a superheater (14) to achieve either an annular flow or an annular mist flow and then sprayed into the evaporator (12) from a nozzle (32) having a shape such that the outlet side first narrows then widens outward, and the aqueous solvent is evaporated and removed.