This project is a side-blown smelting furnace flue gas desulfurization project in Yangchun. Construction started in May 2015. The total flue gas volume of the four furnaces is 200,000m3/h, and the SO2 concentration is 3000-8000mg/Nm3. A two-stage desulfurization tower is designed, using Ca-Ca double alkali. method, lime powder desulfurizer, the SO2 concentration of the flue gas at the outlet of the desulfurization tower is less than or equal to 200mg/m3. The first-stage desulfurization tower has a diameter of 4.8 meters and a height of 22.8 meters, and the second-stage desulfurization tower has a diameter of 4.8 meters and a height of 28.8 meters. It is introduced into the electric mist eliminator through the tower top outlet flue for further treatment, and finally discharged from the chimney. The project adopts PLC+ host computer control system. The electrical equipment in the main process flow adopts two control methods, local and centralized. The process equipment that needs to be automatically adjusted adopts three control methods: local, centralized and PLC.