Design And Improvement Of Extraction Online Dust Concentration Measuring Device

Environmental monitoring is the standard for the state to monitor the discharge of pollutants and to determine whether an enterprise meets the national emission standards.Accurate monitoring of the amount of pollutant emissions is crucial for the state to manage the ecological environment.This paper discusses the monitoring of the concentration of particulates emitted from flue gas.In the past,the measurement method of direct flue gas in the light scattering measurement was easily interfered by various factors such as water vapor.The setting of calibration was performed in different stages and in different time,in addition the weighing method is cumbersome to measure.Based on the above-mentioned problems,this paper designs a device for measuring dust concentration using a light scattering method and a fully automated weighing method.Hardware parts:(1)Design of the overall scheme for extracting on-line smoke and dust concentration measuring devices.Completed the device process design,mechanical structure design,instrument selection and installation,electrical connection and other work,and established the system’s overall control program.(2)The front-end sampling gun is designed to be rapidly heated to more than 120°C in situ,eliminating the influence of water vapor on the fouling of the pipe wall due to condensation in the sampling pipe and the influence of the humidity on the scattered light.(3)The design of the light scattering measurement unit mainly includes the light chamber structure and the corresponding photoelectric monitoring circuit,and a suitable data acquisition module is selected.(4)The fully automatic weighing unit mainly analyzes and designs the manipulator,each station module,weighing module,shock absorption,etc.,and realizes the automatic measurement,drying,film weighing,and replacement of the smoke dust weighing unit of the filter membrane.Software section:PLC as the control core of the entire device completes the overall workflow control,STM32F103VET6 is used as the main control chip of the weighing unit and light scattering unit to complete the action flow control of the weighing unit,and to receive weighing data and process scattered light signal data.The HMI human-computer interaction interface facilitates viewing and maintenance by the staff.PLC,STM32,and HMI communicate with each other to complete the entire process.In this paper,a more comprehensive extraction type of on-line soot concentration measurement device is designed.The whole heat tracing eliminates the measurement effect caused by water vapor liquefaction.The light scattering method and the fully automatic weighing method are integrated into simultaneous,same point calibration and light scattering.The verification of the law provides a valuable reference.Put the device into the field test,according to the actual situation on the spot to find inadequacies to improve.A comparison analysis of the data measured by the two measurement principles leads to conclusions.The next step is to study the existing error problems.The realization of on-line monitoring unattended,is of great significance to the online monitoring of smoke particle concentration.