Flue for desulfurizing absorption tower

The invention discloses a flue for a desulfurizing absorption tower. The flue is characterized in that an inlet and an outlet of the desulfurizing absorption tower are connected with the flue; a reinforcing supporting frame is arranged on the outer portion of the flue, and chattering and vibrating are prevented; the flue is provided with an external reinforcing rib and an internal reinforcing rib, and the outer portion of the flue is wrapped with a heat insulation layer; an overhauling manhole door and a soot clearing hole are formed in the proper position of the flue; a baffle door is arranged in the flue; an expansion joint is arrange at the connecting position of the flue, an expansion joint is also arranged at the connecting position of the flue and the absorption tower, the end of the expansion joint is connected with the flue or the absorption tower through a flange, a non-metal expansion joint is adopted as an inlet and outlet expansion joint of the absorption tower, and non-metal fabric expansion join