Development Of Water Spray Cooling Control System For Gold Smelting Quench Tower

The process of dry quenching arsenic collecting make use of the content of arsenic trioxide is different at different temperature, when the temperature of the flue gas decreased sharply, arsenic trioxide will become a solid precipitation crystallization. Generally the temperature of flue gas at quench tower entrance is about350℃, and at the exit requires130℃.If you add too much water, flue gas with high moisture which affect the following process of electrical dust precipitation, and form slurry at the bottom of the tower, plugging flue. If the water is too little, then the temperature of flue gas doesn’t drop down, will damage the bag of bag dust collector. The main problem that should solved is to design an automatic water spray cooling control system, which can cooled the entrance gas to required temperature, at the same time can make sure not wet the tower wall and the bottom of tower without underflow.This paper gives a design of control system of spray cooling device based on PLC. According to gas component, flue gas volume and the temperature requirements, the theoretical consume of water can be calculated, then select the equipment. The control system mainly consists of the temperature acquisition system, pump water loop, gas supply circuit, PLC control system, two-fluid spray gun.Temperature acquisition system acquisition the entrance and exit temperature by thermal resistance, set reasonable temperature sampling time, carries on the PID operation, then transmits temperature data to the PLC.The PLC control system automatically adjusts the output frequency of the inverter accord to the signal of outlet temperature, and makes the temperature of smoke in a stable range. When the temperature sensor has a fault, the PLC control system detect the pressure of water and gas path, the control system turn to pressure control mode to insure the system working normally, and give an alarm signal to operator.The operation interface of the host computer is designed simply and user-friendly using the configuration software WinCC, The operator can set parameters and operate equipment in the control room.Through the experiment at the factory site, the spray cooling system can automatically adjust water volume and make the temperature of smoke in a stable range. The spray cooling system can also realize communication between the host computer and the field.