The invention relates to the technical field of polyphenylene
sulfide production, in particular to a device and a method for separating NMP (N-Methyl Pyrrolidone) and trichloromethane in a rectification process. The device comprises a first rectifying
tower, a second rectifying
tower, a third rectifying
tower, a fourth rectifying tower, an NMP collecting tank, a first condensing device, a second condensing device, a third condensing device, a fourth condensing device, a first heating device, a second heating device, a third heating device and a fourth heating device. According to the method, trichloromethane is selected as an extraction agent, an NMP-containing
oil phase obtained through extraction is subjected to four-stage rectification, and meanwhile, the temperature of a tower kettle of a rectification tower is controlled, so that
decomposition of trichloromethane is inhibited, the pH value environment in the tower is controlled, equipment
corrosion and generation of other organic impurities due to NMP
hydrolysis are prevented, separation of NMP and trichloromethane is achieved through a low-temperature azeotropic control means, and the yield of NMP is increased. And carrying out
system recycling on the separated NMP and trichloromethane.