Flue gas cooling, dedusting and purifying system

The utility model relates to the technical field of flue gas treatment, in particular to a flue gas cooling, dedusting and purifying system which comprises a bag-type dust collector, the bottom of the bag-type dust collector is connected with a spiral conveyer, an air inlet of the bag-type dust collector is connected with an ash settling barrel, and the top of the ash settling barrel is communicated with a trapezoidal ash hopper through a herringbone flue; the top of the trapezoidal ash hopper is hermetically communicated with a spray tower; the top of the spray tower is provided with an air inlet and a plurality of nozzles; and the bottom of the trapezoidal ash hopper is communicated with a spiral conveyer. The temperature of the flue gas can be reduced through the nozzles arranged on the spray tower, so that the temperature fluctuation of the air inlet of the bag-type dust collector is reduced; by using the herringbone flue, the problem that the flue is blocked when a horizontal flue is used is avoided; and