Chlorine Monitoring System And Chlorine Leak Diffusion Model On Water Treatment

During the process of chlorine disinfection in the water treatment plant, if the chlorine gas leak and without making effective measures to control the leak in time, there may be a great threat to the employees, the atmospheric environment and property. We must detect the leaking as soon as possible, control the hazard scope and take emergency measures properly to reduce the harm caused by the leakage accident. This paper based on chlorine disinfection security in water treatment plant, aim at the low precision and simplex function of domestic product in chlorine monitoring, and overseas equipment is too expensive, developing a high performance price,full function chlorine gas monitoring system used in water treatment plant.This system can realize 8 points on-line checking monitoring, and have double alarm function in monitoring site and monitoring center. The HMI of PC is developed by VB6.0, it has the function of referring the historical events, drawing the real-time curve within a certain time, setting the alarm value of each monitoring point and looking at the nature of chlorine gas,the safe operation documents and the video and so on.First,select the appropriate chlorine gas sensor and temperature-humidity sensor chip and design 4 20mA standard output transmitter circuit and monitoring site alarming circuit; Then, LM3S1138 microcontroller-centered, design hardware and software for monitoring center data acquisition system, use temperature-humidity sensor to measure ambient temperature and use software to compensate the measurement errors; And then diffusion model of chlorine gas was established and make calculation and simulation for it. Gaussian mathematical model is applied in the prediction of chlorine gas spread hazard area and concentration distribution by using Matlab software, providing the basis for establishing the reasonable emergency plans; By simulation, we analyses the influence of atmospheric concentration and wind speed to chlorine gas concentration spread. At last, at the temperature of 24°C, 38% relative humidity, performing the concentration test experiment,gas cross concentration jamming experiment and field testing experiment.It is indicated that this monitoring system has high sensitivity, good linearity, little measure error, and can realize real-time auto-alarm function quickly and accurately; this chlorine gas sensor is insensitive to CO₂, CH₄ and CO, but shows high sensitivity to H₂S, therefore, this system is not suitable for the environment exists H₂S.