Rectification production process, rectification system and production device for parachlorotoluene and o-chlorotoluene

The invention relates to a parachlorotoluene and o-chlorotoluene rectification production process, a rectification system and a production device, and the parachlorotoluene and o-chlorotoluene rectification process comprises the following steps: leading out materials at the top of each rectification tower, and respectively carrying out heat exchange treatment with a medium to obtain steam, so as to recover heat energy of the materials at the top of the rectification tower; one part of the heat-exchanged and condensed material is introduced into the rectifying tower, and the other part of the material is extracted; the steam is pressurized and heated to improve the grade of the steam, the steam with the improved grade is led to the bottom of a rectifying tower to supply heat to the rectifying tower, and the steam is condensed to obtain the medium; and respectively carrying out heat exchange treatment on the condensed medium and the material at the top of each rectifying tower, and circulating in this way. The