| In recent years,China’s improvement in the manufacturing field is obvious to all,but with the economic development,environmental problems have also caught people’s attention.Heavy industrial plants,including metallurgy and power generation,emit pollutant fumes all the time,resulting in smog and acid rain.normal phenomenon.Sulfur dioxide,as one of the polluting gases,can cause acute poisoning when its concentration is high.In mild cases,headache,fatigue,tearing,coughing,and sore throat,in severe cases,it destroys the enzyme activity,causing emphysema,increasing the incidence of carcinogenesis,and forming acid rain into the air changing the acidity and alkalinity of the cultivated land causes a reduction in grain production,and at the same time produces smog containing sulfuric acid,causing damage to textiles,paper products and metal surfaces,and affecting the ecological environment.Based on the current status of flue gas pollution,the National Environmental Protection Agency has taken various preventive measures to reduce the content of pollutants,and it is imperative to use sensing equipment to detect the concentration of polluting gases including sulfur dioxide to implement effective measures.In order to improve the accuracy of detection,first of all,the interference factors caused by the detection of sulfur dioxide are analyzed and studied.In the detection process,the parameters affecting the target gas are studied to improve the detection accuracy.This topic is based on the principle of non-dispersive infrared absorption,the pretreatment structure and related hardware circuits are designed,the particulate matter and moisture of the flue gas are filtered and dehumidified by the filter chamber and the drying device,and the mixed gas is detected by the non-dispersive infrared absorption to reduce the cross between the gases Interference,the experiment verified that there are many factors in the system detection process that affect the detection accuracy of sulfur dioxide.The system is divided into three parts: pretreatment design,detection gas chamber structure design and hardware circuit design.The pretreatment is mainly forthe preparation of gas dedusting and dehumidification to reduce the interference of water vapor.The filter room mainly contains PP filters and the drying device mainly made of Nafion drying tubes are designed to absorb suspended particles and reduce the humidity of sulfur dioxide gas.It has been verified by many experiments that the design flow rate of the air pump is 1L/min;the detection gas chamber is used as the gas flow sampling channel.In order to prevent the inner wall material from absorbing gas,the aluminum inner wall is used for design.The detection air chamber and the detector axis are at the same position;the hardware circuit design mainly includes the sampling signal amplification filter circuit and the control circuit design,and the high-precision,low-power ADu CM360 microcontroller chip is used as the sampling amplification signal analog-to-digital conversion and processing core chip,using the built detection system platform to experiment on the influencing factors of sulfur dioxide interference: Zero point drift is 1.9%,response time is 3.7s,linear error is0.3%,repeatability error is 1.02%;nitrogen dioxide interference on detection is 5.7%,The interference of nitric oxide to the detection is 4.8%,the influence of the sample gas humidity is 3%,the particulate matter impact of 2.8%.Finally,it summarizes the problems encountered in the design of this topic and the subsequent optimization that needs to be carried out,as well as the improvement and prospect of the shortcomings. |
