During the operation of the evaporative crystallization system, if the discharge of some non condensable gases from the vacuum system or the condensing system causes pollution to the environment, it is necessary to install a waste gas treatment system to independently treat the tail gas through various processes such as activated carbon adsorption, washing, ion exchange or introduce the tail gas to the centralized discharge point for centralized treatment. If the treated light component or heavy component liquid needs further environmental protection treatment, tuochi can further provide in-depth treatment solutions according to the working conditions and environmental protection requirements, so as to completely solve the worries behind.