Tail gas recovery apparatus in the production of polyimide film

In this study, the authors discuss the tail gas recovery apparatus used in the production of polyimide film. The title tail gas recovery apparatus includes a condenser, and an absorption column. The condenser is a horizontal pipe-shell condenser with a condensation water inlet and a condensation water outlet at both end, and has a condensate outlet on the bottom. One end of the shell of the condenser is connected with a tail gas inlet pipe, and the other end is connected with the absorption column via a connection pipe. The absorption column includes a vertical column body, a tail gas discharge port, a spraying distributor, a grid plate with filler layer, and several subcritical flow distribution plates. The subcritical flow distribution plates comprise of a kind of orifice plates with decreased apertures from outside to inside, and a kind of orifice plates with increased apertures from outside to inside, and the two kinds of orifice plates are arranged alternately. The condensate outlet is connected with a circulating pump, and the outlet of the circulating pump has two paths with one path connected with the spraying distributor via the absorption liquid inlet, and the other path connected with an absorption liquid storage tank. The tail gas recovery apparatus has high recovery rate over 98% for di-Me acetamide to reduce tail gas pollution, and can recycle di-Me acetamide.