Research And Design Of Automatic System In Water Treat Plant

It is common process in water treating to inject chlorine gas into the process water to keep the concentration of the residual chlorine. The general chlorine gas vacuum dosing system is not precise enough to keep the water residual chlorine and need to be improved.A new chlorination process was introduced in this article based on the actual conditions. The chlorine gas was mixed with the water to gain the high concentration chlorine water, and then the chlorine water is put in the process water by variable frequency dosing pump.The flow of high concentration chlorine water is accurate controlled by dosing pump according to the water flow and the residual chlorine of process water. The dosing pump is regulated by fuzzy control which can ensure the responding speed and stability of the system when the water flow varies quickly, and the capacity of the dosing pump is controled by PID controller based on the actual residual chlorine content.The type of the PLC used is S7-3152DP of SIEMENS and the HMI(human mache inerface) is the WINCC system of SIEMENS too.The new process can decrease the chlorine consumption and increase the stability of the water quality. It uses a variable frequency metering pumps to inject the high concentration chlorine water into the process water by changing the motor speed and the capicity of the dosing pump,and the value of the residual chlorine can be adjusted to the set point soon.