The purification tower is a two-phase countercurrent packing absorption tower. The waste gas enters the purification tower tangentially from the air inlet below the waste gas treatment tower. Under the power of the fan, it quickly fills the space of the air inlet section, and then evenly rises to the first-stage packing absorption section through the equalizing section. On the surface of the filler, the acidic (or alkaline) substances in the gas phase react chemically with the alkaline (or acidic) substances in the liquid phase, and the reacted substances (mostly soluble acids (bases)) flow into the lower storage liquid