CN108801964A - It is a kind of directly to measure formula gaseous pollutant emission monitoring device - Google Patents

Abstract

The invention discloses a direct measurement gaseous pollutant emission monitoring device, which comprises a detection mechanism, an isolation mechanism, an air pumping mechanism, a calibration mechanism, a purging mechanism and a central processing module. The detection mechanism includes a spectrum detection module and a detection room, and the isolation mechanism Including the intake pipe and the smoke valve, the intake pipe and the smoke valve are set in the flue, the inlet of the intake pipe is equipped with a smoke filter cover, the filter is installed in the intake pipe, and the body of the intake pipe is connected with a mark There is a purge pipeline connected to the flue gas filter cover, and a gas flow controller is installed in the exhaust pipeline; the invention can detect gaseous pollutants accurately, and effectively solve the problem that the on-site calibration results of traditional direct measurement detection devices exceed It is easy to operate and occupies a small space. At the same time, it can also accurately measure and calculate the benchmark oxygen-containing emission concentration of gaseous pollutants in flue gas.

Description

A direct measurement gaseous pollutant emission monitoring device

technical field

The invention relates to the technical field of gaseous pollutant measuring equipment, in particular to a direct-measurement gaseous pollutant discharge monitoring device.

Background technique

At present, with the increase of our country's environmental pollution control, the relevant state departments have formulated strict air _pollutant emission standards. Monitoring System Technical Requirements and Detection Methods" (HJ 76-2017), it is clarified that the types of gas pollutant CEMS (Continuous Smoke Emission Monitoring System) include complete extraction method, direct measurement method and dilution extraction method. Due to the limitations of the current detection technology, especially the detection technology of gaseous pollutants containing solid particles, the current CEMS in my country cannot quickly detect the emission status of fixed pollution sources. The main problems are as follows:

1. Both the complete extraction method and the dilution extraction method are extraction CEMS. Extraction CEMS is the most commonly used detection method at present, which can accurately detect the emission status of stationary pollution sources. However, extraction CEMS has a long lag time, for example Take the denitrification CEMS of a thermal power plant as an example. The reaction time of flue gas from the ammonia injection device to the denitrification outlet is about 8 seconds. In actual operation, the measurement results lag behind the actual flue gas pollutant state parameters at the sampling point by about 220S, or even longer. However, China's latest environmental protection standard "Technical Specifications for Continuous Monitoring of Flue Gas (SO2, NO _X , Particulate Matter) Emissions from Fixed Pollution Sources" (HJ 75-2017) can only clearly require the gas pollutant CEMS system during standard gas calibration Response time ≤ 200 seconds. Due to the long lag time, the existing environmental protection equipment in domestic thermal power plants cannot realize automatic adjustment and can only be adjusted manually. However, due to the long lag time, manual adjustment is not reliable and the effect is poor, resulting in frequent exceedance of environmental protection parameters. , Excessive ammonia injection, causing the equipment behind the denitrification to fail to work normally, resulting in blockage of the air preheater, failure of the dust collector and shutdown of the unit, which is neither environmentally friendly nor energy-saving, and has a great potential safety hazard.

Based on the current CEMS technology, the adjustment and control of environmental protection equipment is basically done manually. The environmental protection department can only stipulate that the average value of NOx within one hour cannot exceed the standard, while the power environmental protection inspection department stipulates that the environmental protection parameters cannot exceed 15 times within one hour. , even under this "relaxed" standard, the environmental protection parameters of units monitored by gaseous pollution sources often frequently exceed the requirements of this standard.

2. The direct measurement type CEMS is a method of direct measurement at the sewage discharge site. The spectral detection device is directly installed at the measurement point to directly detect the flue gas. The detection speed is fast, which is conducive to the adjustment of environmental protection equipment and the control and prevention of gaseous pollutants. The environmental protection parameters do not exceed the standard. However, the existing direct measurement measurement technology and devices cannot meet the requirements of environmental protection testing. According to the relevant requirements of environmental protection, the CEMS of the existing direct measurement technology is frequently out of tolerance when performing on-site detection and comparison. The existing direct measurement The technical CEMS is often out of tolerance when it is calibrated, which does not meet the requirements of environmental protection testing. At present, with the intensification of environmental protection monitoring, various thermal power plants and gaseous pollution source monitoring units with high content of solid particulate matter have all eliminated direct measurement CEMS and replaced them with extraction and dilution sampling CEMS, imported brands Many CEMS manufacturers can't provide direct measurement CEMS that meets the requirements of environmental testing.

Due to the insurmountable technical bottlenecks in the existing direct measurement gas pollutant measurement technology, the basic functions of the existing direct measurement gas pollutant measurement devices do not meet the requirements of environmental protection testing, and the technical bottleneck mainly includes the following aspects:

(1) When the direct measurement CEMS device conducts continuous monitoring of gaseous pollutants, the environment of the measuring point is extremely harsh. For example, the temperature of the flue gas at the denitrification CEMS measuring point of a thermal power plant is as high as 370 degrees, and the dust content is relatively large, such as , the humidity of flue gas using wet desulfurization is relatively high, and the CEMS device is affected by the environment. The detection probe of the direct-measurement CEMS device is directly installed in the flue gas pipeline. When the CEMS device is calibrated with standard gas, the standard gas enters the flue gas detection channel, and the standard gas and flue gas are mixed. The gas entering the detection channel during calibration is mixed The mixed gas of the calibration gas and flue gas with an uncertain ratio is not the calibration gas, and the calibration result is uncertain, which directly leads to out-of-tolerance calibration results during the environmental protection on-site calibration, which does not meet the requirements of environmental supervision and smoke; therefore, the direct measurement method CEMS devices are generally calibrated by the following method: insert a filter lens or "real" lens with similar absorption characteristics to pollutants in the optical path, and then calculate the calibration result after calculation. The inconsistency between the lens and the real lens and the calibration gas detection conditions causes environmental protection. On-site comparative monitoring results were out of tolerance.

(2) When the existing direct measurement measurement technology and device are compared and tested on the environmental protection site, the newly introduced trace amount of flue gas is mixed with the flue gas of the previous period in the hysteresis space inside the filter, and the mixed flue gas enters the In the sample gas detection room, the results cannot represent the instantaneous and real-time concentration of gaseous pollutants, and cannot detect the maximum value of gaseous pollutants; when compared with the standard instrument detection results of environmental protection comparison monitoring, the results are out of tolerance, which cannot meet the environmental protection detection requirements.

(3) At present, the country requires environmental protection and ultra-low emissions, and the detection accuracy of CEMS must meet the ultra-low emission requirements; the existing direct measurement gas pollutant measurement technology and devices have a large range, which cannot meet the ultra-low emission detection accuracy requirements . The longer the travel of the light emitted by spectral analysis in the detection chamber, the higher the accuracy of spectral analysis. Only by increasing the travel of light in the detection chamber can the ultra-low emission detection requirements be met. However, if the length of the sample gas detection chamber is directly increased, the Under the long-term high-temperature working environment, the detection chamber naturally creeps and sags and bends, which affects the normal optical path of the light, and the stability of the instrument is poor; at the same time, the direct measurement measurement device needs to be tested on site, and the increase in the length of the detection chamber will cause The increase in volume is not convenient for on-site operation.

(4) According to the "Emission Standards of Air Pollutants for Thermal Power Plants", the emission concentration of gaseous pollutants needs to be converted into a benchmark oxygen concentration based on the measured oxygen content, and the environmental protection department conducts assessment according to the benchmark oxygen concentration of gaseous pollutants; The measuring points of the type gaseous pollutant emission monitoring device and the measuring point of the oxygen content concentration detection device are set at different positions and are independently detected, and because the existing direct measurement gaseous pollutant emission monitoring device, oxygen content detection The basic function of the device itself does not meet the requirements of environmental protection testing, resulting in the detected content of gaseous pollutants and the oxygen content of gaseous pollutants within the same period of time, and the benchmark oxygen-containing emission concentration of gaseous pollutants in the sample gas cannot be accurately calculated .

To sum up, although direct measurement CEMS has many advantages, there are problems in the above basic functions, which make it impossible to meet the requirements of environmental protection testing. Therefore, how to solve the problems of the existing direct measurement gas pollutant measurement technology that has been eliminated Technical bottleneck, designed a direct measurement gas pollutant monitoring device CEMS that meets the requirements of environmental protection testing, meets the needs of automatic adjustment of environmental protection equipment operation, realizes the perfect combination of environmental protection monitoring and automatic control of environmental protection equipment operation, and has a great impact on the detection and control of pollution emissions. It is of great significance and will bring significant progress to the detection technology in this field.

Contents of the invention

The purpose of the present invention is to provide a direct measurement gaseous pollutant discharge monitoring device, which can detect gaseous pollutants accurately, and effectively solve the problems of large tolerance and low purity of sample gas existing in traditional direct measurement detection devices, and improve detection accuracy , and it is easy to operate and takes up little space. At the same time, it can also accurately calculate the benchmark oxygen-containing emission concentration of gaseous pollutants in the sample gas.

The technical scheme adopted in the present invention is:

A direct measurement gaseous pollutant emission monitoring device, including a detection mechanism, an isolation mechanism, an air extraction mechanism, a calibration mechanism, a purging mechanism and a central processing module;

The detection mechanism includes a detection room, the left side of the detection room is provided with a spectrum detection module connected to the interior of the detection room, a main reflector is arranged in the detection room, and the spectrum detection module is set opposite to the main reflector; the spectrum detection module includes a light source module and a spectrum Receive analysis module;

The isolation mechanism includes the air intake pipe connected to the right end of the detection chamber and the smoke valve installed at the entrance of the air intake pipe. The air intake pipe and the smoke valve are arranged in the flue. There is a filter in the pipeline;

The air extraction mechanism includes an air extraction pipeline, an air extraction valve and an air extraction pump. The inlet of the air extraction pipeline is connected to the left end of the detection chamber, the outlet of the air extraction pipeline is connected to the air extraction pump, and the air extraction valve is arranged in the air extraction pipeline;

The calibration mechanism includes a calibration gas pipeline and a calibration gas inlet valve arranged on the calibration gas pipeline. The inlet end of the calibration gas pipeline is connected to an external standard gas source, and the outlet end of the calibration gas pipeline is connected to the inlet pipeline. The outlet end of the calibration gas pipeline is located at the smoke valve. and between filters;

The purge mechanism includes a purge pipe, a purge inlet valve and a gas flow controller. The intake valve is set on the purge pipeline, and the gas flow controller is set on the exhaust pipeline;

The controlled end of the light source module is connected to the light source control end of the central processing module, the communication end of the spectrum receiving and analysis module is connected to the spectrum analysis communication end of the central processing module, the communication end of the gas flow controller is connected to the flow communication end of the central processing module, and the central processing module pumps air The control end is connected to the controlled end of the air pump.

In order to reduce the attenuation during light transmission and improve the accuracy of spectrum detection, further, the light source module is connected to the detection chamber through the emission fiber unit, and the spectrum receiving and analysis module is connected to the detection chamber through the reflection fiber unit, and the emission fiber unit is arranged between the light source module and the detection chamber. Between the main reflectors, the reflective fiber unit is arranged between the main reflector and the spectrum receiving analysis module; the launch fiber unit includes a launch lens and a launch light guide fiber, and the launch lens and launch light guide fibers are launched along the light source module to the main reflector The direction of the light path is arranged in sequence, and the reflective fiber unit includes a reflective lens and a reflective light-guiding fiber. The reflective lens and the reflective light-guiding fiber are arranged in sequence along the direction of the light path reflected from the main reflector to the spectrum receiving and analyzing module.

In order to increase the distance of the light in the detection chamber without lengthening the detection chamber, further, the detection chamber is provided with a secondary reflector, which is located on the left side of the primary reflector and opposite to the primary reflector.

In order to comprehensively consider the influence of temperature and pressure during spectral analysis and improve the accuracy of analysis, further, the detection mechanism also includes a temperature sensor and a pressure sensor arranged in the detection chamber, and the output terminals of the temperature sensor and the pressure sensor are respectively connected to the spectral receiving analysis Module signal input terminal.

In order to be able to detect the oxygen concentration in the sample gas on the same set of equipment, it further includes an oxygen detection module arranged on the exhaust pipeline, the output end of the oxygen detection module is connected to the detection signal input end of the central processing module; When detecting the content of gas pollutants in the sample gas, the oxygen detection module directly detects the oxygen content of the same sample gas. When the detection mechanism performs calibration of the calibration gas, the calibration gas enters the oxygen detection module at the same time to calibrate the oxygen detection module.

Further, the intake pipe is provided with a _NOx converter, and the _NOx converter is arranged between the outlet end of the calibration gas pipe and the filter.

Further, the smoke valve adopts a check valve or a long rod control valve.

Further, the air pump adopts an air ejector, and the air ejector is provided with a compressed air inlet, a sample gas suction port and a sample gas outlet, the compressed air inlet is connected to an external air source, and the sample gas suction port is connected to The exhaust pipe and the sample gas outlet are connected to the gas outlet pipe, and the gas outlet pipe is connected to the inside of the flue.

Further, the light emitted by the light source module is ultraviolet light.

Furthermore, when calibration gas is used for calibration, the calibration gas inlet valve is opened, the smoke valve is closed, the calibration gas is isolated from the smoke in the filter cover, the smoke cannot enter the intake pipe and mix with the calibration gas, and the calibration gas does not Will leak from the intake duct into the flue.

The present invention has the following beneficial effects:

(1) By setting the isolation mechanism, the smoke valve is opened when the sample gas enters the detection room from the intake pipe to ensure the normal flow of the smoke gas. When the calibration gas is calibrated, the smoke valve in the detection room is closed, and the gas calibration is realized. The complete isolation of the standard gas and the flue gas avoids the inaccurate calibration caused by the mixing of the sample gas into the standard gas, ensures the accuracy of the calibration results, and makes the calibration results accurate and unique when the sample gas is calibrated on the environmental protection site, thereby ensuring that the present invention can Meet the use requirements of environmental testing;

(2) By setting the flue gas filter cover in the flue and extending the intake pipe into the structure of the sample gas filter cover, while ensuring the increase of the filter flow rate, it is possible to prevent resistance from affecting the sample gas flow rate, and at the same time, the intake air The pipeline is set in the flue gas filter cover, which compresses the gas hysteresis space inside the filter cover;

(3) By setting up the purge mechanism, when the gas flow controller detects that the gas flow rate of the exhaust pipe is less than the limited threshold, the flue gas filter cover will be cleaned in time to avoid the blockage of the flue gas filter cover under long-term use and thus affect the The sample gas flow rate further ensures the detection accuracy of the sample gas. At the same time, the purge mechanism cooperates with the use of the flue gas valve to prevent the gas from flowing into the detection chamber during purge, causing the gas in the detection chamber to mix and cause inaccurate detection results of the sample gas;

(4) By installing an optical fiber connection module between the spectrum detection module and the detection room, it not only isolates the spectrum detection module from the detection room, but also prevents the high temperature gas in the detection room from damaging the spectrum detection module, ensuring the safe use of the equipment and improving the service life of the equipment , while reducing the attenuation in light transmission to ensure the accuracy of spectral analysis results;

(5) By setting the sub-reflector, the light source emitted by the light source module will enter the spectrum receiving and analyzing module after multiple reflections between the reflector and the sub-reflector. Without increasing the length of the detection chamber, the light in the The optical path in the sample gas in the detection chamber improves the detection accuracy of the present invention;

(6) By setting up a high-temperature-resistant oxygen detection module, the oxygen content of the sample gas is directly measured without cooling or other treatment, so that the detected gaseous pollutant content and the actual oxygen content converted from the benchmark oxygen-containing emission concentration are at the same During the period of time, and the oxygen sensor can be calibrated synchronously during the functional calibration of the gaseous pollutant detection device, so as to facilitate more accurate calculation of the benchmark oxygen-containing emission concentration of pollutants in the sample gas.

Description of drawings

Fig. 1 is the structural representation of embodiment one;

Fig. 2 is a schematic structural diagram of Embodiment 1 in use;

Fig. 3 is the structural representation of embodiment two;

Fig. 4 is a schematic structural diagram of Embodiment 2 in use;

Fig. 5 is the structural representation of embodiment three

Fig. 6 is a schematic structural view of Embodiment 3 in use;

The structural schematic diagram of the fourth embodiment of Fig. 7;

Fig. 8 is a schematic structural view of the fourth embodiment in use.

Explanation of reference signs:

1. Detection room; 2. Spectrum receiving analysis module; 3. Light source module; 4. Air extraction valve; 5. Air extraction pipeline; 6. Gas flow controller; 7. Air extraction pump; 8. Purge intake valve; 9 1. Purge pipeline; 10. Standard gas pipeline; 11. Standard gas intake valve; 12. Smoke filter cover; 13. Main reflector; 14. Check valve; 15. Intake pipeline; 16. Filter; 17 , fixed flange; 18, flue wall; 19, NOx converter; 20, secondary reflector; 21, temperature sensor; 22, pressure sensor; 23, launch fiber unit; 24, long rod control valve; 25, launch fiber unit; 26. sealing sleeve; 27. outlet pipe; 28. oxygen detection module.

Detailed ways

The invention includes a detection mechanism, an isolation mechanism, an air pumping mechanism, a calibration mechanism, a purging mechanism and a central processing module;

The detection mechanism includes a detection chamber 1, the left side of the detection chamber 1 is provided with a spectrum detection module communicated with the interior of the detection chamber 1, the detection chamber 1 is provided with a main reflector 13, and the spectrum detection module is arranged opposite to the main reflector 13; The detection module includes a light source module 3 and a spectrum receiving analysis module 2;

The isolation mechanism includes an air intake pipe 15 connected to the right end of the detection chamber 1. The air intake pipe 15 extends into the flue wall 18 and is arranged in the flue. A flue gas valve and a filter 16 are arranged in sequence along the flow direction of the air flow, and the filter 16 adopts a non-planar convex-concave structure to increase the air flow; the flue gas valve adopts a check valve 14 or a long rod control valve 24;

The air extraction mechanism includes an air extraction pipeline 5, the inlet of the air extraction pipeline 5 is connected to the left end of the detection chamber 1, the outlet of the air extraction pipeline 5 is provided with an air extraction pump 7, and the air extraction pipeline 5 is provided with an air extraction valve 4;

The calibration mechanism includes a calibration gas pipeline 10 and a calibration gas inlet valve 11 arranged on the calibration gas pipeline 10. The inlet end of the calibration gas pipeline 10 is connected to an external standard gas source, and the outlet end of the calibration gas pipeline 10 is connected to an intake pipeline 15. The outlet end of the pipeline 10 is located between the smoke valve and the filter 16;

The purge mechanism includes a purge pipe 9, a purge inlet valve 8 and a gas flow controller 6. The inlet end of the purge pipe 9 is connected to an external standard gas source, and the outlet end of the purge pipe 9 extends into the flue and is connected to the flue gas filter. Inside the cover 12, the purge intake valve 8 is set on the purge pipeline 9, and the gas flow controller 6 is set on the exhaust pipeline 5;

The controlled end of the light source module 3 is connected to the light source control end of the central processing module, the communication end of the spectrum receiving analysis module 2 is connected to the spectrum analysis communication end of the central processing module, the communication end of the gas flow controller 6 is connected to the flow communication end of the central processing module, and the central processing The air extraction control end of the module is connected to the controlled end of the air extraction pump 7 .

In order to better understand the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings.

Embodiment one:

As shown in Figures 1 and 2, this embodiment includes a detection mechanism, an isolation mechanism, an air extraction mechanism, a calibration mechanism, a purging mechanism and a central processing module;

The detection mechanism includes a detection chamber 1. The right end of the detection chamber 1 extends into the flue and the detection chamber 1 is fixed on the flue wall 18 through a fixed flange 17. The left end of the detection chamber 1 is connected to the exhaust mechanism, and the right end of the detection chamber 1 is respectively connected to the isolation mechanism and Calibration agency. The left side of the detection room 1 is provided with a spectrum detection module connected to the inside of the detection room 1. The spectrum detection module includes a light source module 3 and a spectrum receiving analysis module 2. The detection room 1 is provided with a main reflector 13, and the main reflector 13 is located in the detection room. 1. The right end is opposite to the spectral detection module, and the main reflector 13 is preferably a triangular mirror. Wherein, the spectral receiving and analyzing module 2 includes a laser receiving module for receiving reflected light and an analyzer for performing spectral analysis.

The isolation mechanism is set in the flue and is used to filter the sample gas. The isolation mechanism includes an air intake pipe 15 connected to the right end of the detection chamber 1. The entrance of the air intake pipe 15 is covered with a smoke filter cover 12. The air intake pipe at the far right end 15 The inlet is provided with a flue gas generator, and the flue gas valve adopts an electric control valve or a check valve 14 with a one-way flow function. In this embodiment, a check valve 14 is preferably used, and the flow direction of the check valve 14 is from right to left. That is, in line with the flow direction of the sample gas, a filter 16 is provided in the intake pipe 15 on the left side of the check valve 14 .

The flue gas filter cover 12 preferably adopts a metal powder sintered filter element with an elliptical radial cross-section. The elliptical columnar structure has a larger surface area under the same volume, so the filtering area of the smoke filter cover 12 can be effectively increased, so that the smoke filter cover The ventilation rate of 12 can reach 0.8L/min, which can increase the surface area of the flue gas filter cover 12 and increase the flow rate without increasing the resistance. At the same time, it can also reduce the gas hysteresis space inside the filter 16.

By adopting the smoke filter cover 12 made of metal powder sintered filter element, and setting the radial section of the smoke filter cover 12 as a non-circular shape, on the premise of not increasing the internal volume of the smoke filter cover 12, the It can increase the surface area of the flue gas filter cover 12, increase the flow rate of the sample gas, and ensure that a large amount of new flue gas can quickly replace all the gas in the hysteresis space, so that all the gas in the detection chamber 1 is new flue gas. Furthermore, it is ensured that the detection results can accurately represent the instantaneous and real-time concentrations of gaseous pollutants, so that the present invention can be consistent with the detection results of standard instruments when performing environmental protection comparison monitoring, and meet the requirements of environmental protection detection;

The air extraction mechanism includes an air extraction pipeline 5, the inlet of the air extraction pipeline 5 is connected to the left end of the detection chamber 1, the outlet of the air extraction pipeline 5 is provided with an air extraction pump 7, and the air extraction pipeline 5 is provided with an air extraction valve 4;

The calibration mechanism includes a calibration gas pipeline 10 and a calibration gas inlet valve 11 arranged on the calibration gas pipeline 10. The inlet end of the calibration gas pipeline 10 is connected to an external standard gas source, and the outlet end of the calibration gas pipeline 10 is connected to an intake pipeline 15. The gas outlet end of the pipeline 10 is located between the check valve 14 and the filter 16;

The purge mechanism includes a purge pipe 9, a purge inlet valve 8 and a gas flow controller 6. The inlet end of the purge pipe 9 is connected to an external standard gas source, and the outlet end of the purge pipe 9 extends into the flue and is connected to the flue gas filter. Inside the cover 12 , the purge inlet valve 8 is arranged on the purge pipeline 9 , and the gas flow controller 6 is arranged on the exhaust pipeline 5 .

The controlled end of the light source module 3 is connected to the light source control end of the central processing module, the communication end of the spectrum receiving analysis module 2 is connected to the spectrum analysis communication end of the central processing module, the communication end of the gas flow controller 6 is connected to the flow communication end of the central processing module, and the central processing The air extraction control end of the module is connected to the controlled end of the air extraction pump 7 .

The working principle of embodiment one is:

When the sample gas is detected, the exhaust valve 4 and the exhaust pump 7 are opened, the calibration gas intake valve 11 and the purge intake valve 8 are closed, a negative pressure suction is generated in the smoke filter cover 12, and the sample gas in the flue enters the flue gas filter Cover 12, after filtering solid particles in the flue gas, after passing through the return valve 14, the intake pipe 15 and the filter 16 in sequence, the clean sample gas containing gas pollutants SO ₂ and NO _X enters the detection chamber 1 through the detection chamber 1 Spectral detection is carried out, and then enters the air extraction pipeline 5, the gas flow controller 6, and is discharged by the air extraction pump 7.

The spectrum analysis process of this embodiment is as follows: the light source module 3 emits light in the ultraviolet band into the detection chamber 1, and the light enters the spectrum receiving and detection module after being reflected by the main reflector 13, because SO ₂ and NO _x in the sample gas will absorb the light in the detection chamber 1 The characteristic band in the light, the spectrum receiving analysis module 2 analyzes the spectrum of the light absorbed by the gas pollutant to obtain the concentration of the gas pollutant.

The spectrum detection module preferably adopts an integrated spectrum receiving module and a spectrum analyzer. The spectrum receiving module receives the reflected light beam and analyzes the gaseous pollutants through the spectrometer.

When the calibration gas is calibrated, the exhaust valve 4 and the calibration gas intake valve 11 are opened, the air extraction pump 7 and the purge intake valve 8 are closed, and under the action of the calibration gas pressure, the calibration gas enters the calibration gas pipeline 10. Check valve 14, the check valve 14 is closed under the pressure of the calibration gas, the calibration gas will not leak into the flue from the intake pipe 15, and the flue gas cannot enter the intake pipe 15 due to the closure of the check valve 14; the calibration gas passes through After the filter 16 enters the detection chamber 1, the spectral detection module performs spectral analysis and parameter calibration, and the calibration gas finally flows through the exhaust pipe 5 and the gas flow controller 6 to be discharged. The calibration interval is set according to the "Technical Specifications for Continuous Monitoring of Flue Gas (SO2, NOX, Particulate Matter) Emissions from Fixed Pollution Sources" (HJ 75-2017), and automatic calibration is performed at least once every 24 hours.

The process of spectral analysis and parameter calibration is as follows: the ultraviolet band light emitted by the light source module 3 enters the detection chamber 1, and enters the spectrum detection module after being reflected by the main reflector 13. SO ₂ and NO _X in the standard gas absorb the light in the detection chamber 1 The spectrum detection module analyzes the spectrum of the light absorbed by the gas pollutants to obtain the pollutant concentration of the standard gas, and then adjusts the indication value of the spectrum receiving analysis module 2 so that the indication value of the spectrum receiving analysis module 2 is consistent with the The standard value is consistent, and the calibration process is completed.

During the above-mentioned sample gas detection and process, the gas flow controller 6 detects the gas flow in the exhaust pipe 5 in real time. When the flow value is less than the defined threshold, it proves that the smoke filter cover 12 is blocked. At this time, the exhaust valve 4 , suction pump 7, and standard gas inlet valve 11 are all closed, the purge inlet valve 8 is opened, the external compressed air source enters the inside of the smoke filter cover 12 through the purge pipe 9, and the smoke filter cover 12 is purged from the inside to the outside , remove the dust on the surface of the flue gas filter cover 12. The value of the flow limit threshold needs to ensure that the flue gas flow through the monitoring device is stable, and at the same time meet the "Technical Requirements and Detection Methods for Continuous Monitoring System of Flue Gas (SO2, NOX, Particulate Matter) Emissions from Stationary Pollution Sources" (HJ 76-2017). Influence of sample flow change" technical indicators meet the requirements.

Embodiment two:

As shown in Figure 3 and Figure 4, the difference between this embodiment and Embodiment 1 is:

The detection chamber 1 is provided with a temperature sensor 21 and a pressure sensor 22, the detection chamber 1 is provided with a main reflector 13 at the right end, the left end of the detection chamber 1 is provided with a secondary reflector 20 corresponding to the main reflector 13, and the detection chamber 1 is at the right end. A check valve 14 , a NOx converter 19 and a filter 16 are sequentially arranged on the communicating intake pipe 15 from right to left, and the NOx converter 19 is located between the outlet end of the calibration gas pipe 10 and the filter 16 .

The main reflector 13 comprises x triangular mirrors arranged side by side, and the secondary reflector 20 comprises x-1 triangular mirrors arranged side by side, the triangular mirror of the main reflector 13 is arranged towards the left, and the triangular mirror of the secondary reflector 20 is set towards the right, The i-th triangular mirror lower half of the sub-reflector 20 is set opposite to the i-th triangular mirror upper half of the main reflector 13, i=1, 2, ..., x-1; The transmission process between the sub-reflectors 20 is: the light emitted by the light source module 3 enters the first triangular mirror of the main reflector 13, and the first triangular mirror of the main reflector 13 reflects the light to the first triangular mirror of the sub-reflector 20. 1 triangular mirror, then reflected by the 1st triangular mirror of the secondary reflector 20 to the 2nd triangular mirror of the main reflector 13, until the light is reflected to the main reflector 20 by the x-1 triangular mirror 20 of the secondary reflector 20 After the xth triangular mirror of the reflector 13, the light is finally reflected by the xth triangular mirror of the main reflector 13 to the spectrum receiving and analyzing module 2 on the left.

The light source module 3 is connected to the detection chamber 1 through the emission fiber unit 23, and the spectrum receiving analysis module 2 is connected to the detection chamber 1 through the reflection fiber unit 25. The emission fiber unit 23 is arranged between the light source module 3 and the main reflector 13, and the reflection fiber unit 25 is arranged Between the main reflector 13 and the spectrum receiving and analyzing module 2; the emitting fiber unit 23 includes an emitting lens and an emitting light-guiding fiber, and the emitting lens and the emitting light-guiding fiber are arranged in sequence along the light path direction of the light source module 3 emitting to the main reflector 13, The reflective fiber unit 25 includes a reflective lens and a reflective light-guiding fiber. The reflective lens and the reflective light-guiding fiber are sequentially arranged along the direction of the light path reflected by the main reflector 13 to the spectrum receiving and analyzing module 2 .

The working principle of embodiment two is:

When the sample gas is detected, the exhaust valve 4 and the exhaust pump 7 are opened, the calibration gas intake valve 11 and the purge intake valve 8 are closed, a negative pressure suction is generated in the smoke filter cover 12, and the sample gas in the flue enters the flue gas filter Cover 12, after filtering solid particles in the flue gas, after passing through the intake pipe 15, NOx converter 19 and filter 16 in sequence, the clean sample gas containing gas pollutants SO ₂ and NO _X enters the detection chamber through the detection chamber 1 1 for spectral detection, then enters the air extraction pipeline 5 and is discharged by the air extraction pump 7.

The spectrum analysis process of this embodiment is: the light source module 3 emits light in the ultraviolet band, the light in the ultraviolet band passes through the detection chamber 1 through the emitting light unit and propagates to the main reflector 13, and then passes through the main reflector 13 and the secondary reflector 20 After multiple reflections, the light in the ultraviolet band finally enters the spectrum receiving and detecting module through the reflecting optical fiber unit 25. Since SO ₂ and NO _X in the sample gas will absorb the characteristic bands of the light in the detection chamber 1, the spectrum receiving and analyzing module 2 The spectrum of the light absorbed by the gas pollutants is analyzed, and according to the temperature signal detected by the temperature sensor 21 and the pressure signal detected by the pressure sensor 22, the concentration of the gas pollutants is obtained through analysis by a spectrum analyzer.

When the calibration gas is calibrated, the exhaust valve 4 and the calibration gas intake valve 11 are opened, the air extraction pump 7 and the purge intake valve 8 are closed, and the check valve 14 cannot leak into the smoke from the intake pipe 15 due to the non-return function. The flue gas cannot enter the intake pipe 15; under the pressure of the standard gas, the external standard gas source enters the detection chamber 1 through the standard gas pipe 10 and the filter 16 in turn, and the spectral detection module performs spectral analysis and parameter calibration , the calibration gas finally flows through the exhaust pipe 5 and the gas flow controller 6 before being discharged.

Embodiment three:

As shown in Figure 5 and Figure 6, the difference between this embodiment and Embodiment 1 is:

The outer circumference of the detection chamber 1 is provided with a sealing sleeve 26, and the outer diameter of the sealing sleeve 26 is not smaller than the maximum outer diameter of the smoke filter cover 12; the detection chamber 1 is equipped with a temperature sensor 21 and a pressure sensor 22, and the temperature sensor 21 and the pressure sensor 22 is located at the left end of the detection chamber 1 and is used to detect the temperature and pressure of the sample gas in the detection chamber 1 respectively.

The flue gas valve in this embodiment adopts a long rod control valve 24, and the long rod control valve 24 includes a valve body, a valve rod and an actuator. The actuator is located outside the flue wall 18, and the valve body and the actuator are connected through the rotation of the valve rod to realize the long-distance control of the valve body by the actuator.

The light source module 3 is connected to the detection chamber 1 through the emission fiber unit 23, and the spectrum receiving analysis module 2 is connected to the detection chamber 1 through the reflection fiber unit 25. The emission fiber unit 23 is arranged between the light source module 3 and the main reflector 13, and the reflection fiber unit 25 is arranged Between the main reflector 13 and the spectrum receiving and analyzing module 2; the emitting fiber unit 23 includes an emitting lens and an emitting light-guiding fiber, and the emitting lens and the emitting light-guiding fiber are arranged in sequence along the light path direction of the light source module 3 emitting to the main reflector 13, The reflective fiber unit 25 includes a reflective lens and a reflective light-guiding fiber. The reflective lens and the reflective light-guiding fiber are sequentially arranged along the direction of the light path reflected by the main reflector 13 to the spectrum receiving and analyzing module 2 .

The working principle of embodiment three is:

When the sample gas is detected, the long rod control valve 24, the air extraction valve 4 and the air extraction pump 7 are opened, the calibration gas intake valve 11 and the purge intake valve 8 are closed, and negative pressure suction is generated in the smoke filter cover 12, and the air in the flue is The sample gas enters the flue gas filter cover 12, and the sample gas after filtering out solid particles passes through the long-stem control valve 24, the intake pipe 15 and the filter 16 in sequence, and then, the clean sample gas containing gas pollutants SO ₂ and NO _X Enter the detection chamber 1 through the detection chamber 1 for spectral detection, then enter the air extraction pipe 5, the gas flow controller 6, and be drawn out by the air extraction pump 7 into the flue to avoid polluting the air.

During the above-mentioned sample gas detection and process, the gas flow controller 6 detects the gas flow in the exhaust pipe 5 in real time. When the flow value is less than the defined threshold, it proves that the flue gas filter cover 12 is blocked. At this time, the long rod control The valve 24 and the standard gas inlet valve 11 are closed, the purge inlet valve 8 is opened, the external compressed air source enters the inside of the smoke filter cover 12 through the purge pipe 9, and the smoke filter cover 12 is purged from the inside to the outside to remove the smoke. Air filter cover 12 surface dust. The value of the flow limit threshold needs to ensure that the flue gas flow through the monitoring device is stable, and at the same time meet the "Technical Requirements and Detection Methods for Continuous Monitoring System of Flue Gas (SO2, NOX, Particulate Matter) Emissions from Stationary Pollution Sources" (HJ 76-2017). Influence of sample flow change" technical indicators meet the requirements.

The spectrum analysis process of this embodiment is: the light source module 3 emits light in the ultraviolet band, and the light in the ultraviolet band enters the spectrum receiving and detecting module after being reflected by the main reflector 13, because SO ₂ and NO _x in the sample gas will absorb The spectrum receiving and analyzing module 2 analyzes the spectrum of the light absorbed by the gas pollutants, and according to the temperature signal detected by the temperature sensor 21 and the pressure signal detected by the pressure sensor 22, the gas pollution is analyzed and obtained through the spectrum analyzer. substance concentration.

During calibration, the exhaust valve 4, air pump 7 and calibration gas inlet valve 11 are opened, the long rod control valve 24 is closed, the smoke valve is the long rod control valve 24 is in a closed state, and the calibration gas cannot flow from the intake pipe 15 Leakage enters the flue, and the flue gas cannot enter the intake pipe 15; under the suction effect of the air pump 7, the external calibration gas source enters the detection chamber 1 through the calibration gas pipeline 10 and the filter 16 in turn, and the spectral detection module Spectral analysis and parameter calibration are carried out. The calibration gas finally passes through the exhaust pipe 5, the gas flow controller 6 and the exhaust pump 7 in sequence, and is finally discharged into the flue by the exhaust pump 7.

Embodiment four:

As shown in Figure 7 and Figure 8, the difference between this embodiment and Embodiment 3 is:

In this embodiment, the smoke valve adopts a check valve 14, and the check valve 14 is arranged at the entrance of the rightmost end of the intake pipe 15, and the intake pipe 15 communicates with the smoke filter cover 12 through the check valve 14, and the check valve The flow direction of 14 is from right to left, that is, it is consistent with the flow direction of the sample gas, and a filter 16 is provided in the intake pipe 15 on the left side of the check valve 14 .

The air extraction pipeline 5 is provided with an oxygen detection module 28, the oxygen detection module 28 is located between the air extraction valve 4 and the air extraction pump 7 and is used for real-time detection of the oxygen concentration in the sample gas, and the output end of the oxygen detection module 28 is connected to the detection signal of the central processing module input.

The air pump 7 adopts an air ejector, and the air ejector is provided with a compressed air inlet, a sample gas suction port and a sample gas outlet, the compressed air inlet is connected to an external pressure gas source, and the sample gas suction port is connected to a suction pipe. The sample gas outlet is connected to the gas outlet pipeline 27 .

The working principle of embodiment four is:

When the sample gas is detected, the check valve 14, the exhaust valve 4 and the exhaust pump 7 are opened, the calibration gas intake valve 11 and the purge intake valve 8 are closed, and a negative pressure suction is generated in the flue gas filter cover 12, and the sample in the flue is The gas enters the flue gas filter cover 12, and the sample gas after filtering out the solid particles in the flue gas passes through the check valve 14, the intake pipe 15 and the filter 16 in turn, and then, the clean gas containing SO ₂ and NO _X The sample gas enters the detection chamber 1 for spectral detection, then flows through the exhaust pipe 5, the oxygen detection module 28 and the gas flow controller 6 in sequence, and is finally discharged into the flue by the exhaust pump 7 to avoid polluting the air.

The spectrum analysis process of this embodiment is: the light source module 3 emits light in the ultraviolet band, and the light in the ultraviolet band enters the spectrum receiving and detecting module after being reflected by the main reflector 13, because SO ₂ and NO _x in the sample gas will absorb the For the characteristic bands in the light, the spectrum receiving analysis module 2 analyzes the spectrum of the light absorbed by the gas pollutants, and according to the temperature, pressure and oxygen content data, analyzes and obtains the concentration of the gas pollutants through a spectrum analyzer; At the same time, the oxygen detection module 28 analyzes the oxygen content in the high-temperature sample gas to obtain the oxygen concentration.

When the calibration gas is calibrated, the exhaust valve 4, the air pump 7 and the calibration gas intake valve 11 are opened, and the check valve 14 and the purge intake valve 8 are closed. Under the action of the one-way circulation of the check valve 14, the calibration gas cannot Leaking from the intake pipe 15 into the flue, the flue gas cannot enter the intake pipe 15 due to the lack of negative pressure, which ensures the purity of the sample gas; the external calibration gas source passes through the calibration gas pipeline 10 and the filter 16 before entering the detection In room 1, the spectral detection module performs spectral analysis and parameter calibration. Then, the calibration gas enters the exhaust pipe 5, the oxygen detection module 28, the gas flow controller 6 and the air pump 7, and finally is discharged into the flue through the air pump 7. At the same time, the oxygen detection module 28 performs oxygen content analysis and calibration.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or some or all of the technical features are equivalently replaced, and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A direct measurement type gaseous pollutant emission monitoring device, characterized in that: comprising a detection mechanism, an isolation mechanism, an air extraction mechanism, a calibration mechanism, a purging mechanism and a central processing module; The detection mechanism includes a detection room, the left side of the detection room is provided with a spectrum detection module connected to the interior of the detection room, a main reflector is arranged in the detection room, and the spectrum detection module is set opposite to the main reflector; the spectrum detection module includes a light source module and a spectrum Receive analysis module; The isolation mechanism includes the air intake pipe connected to the right end of the detection chamber and the smoke valve installed at the entrance of the air intake pipe. The air intake pipe and the smoke valve are arranged in the flue. There is a filter in the pipeline; The air extraction mechanism includes an air extraction pipeline, an air extraction valve and an air extraction pump. The inlet of the air extraction pipeline is connected to the left end of the detection chamber, the outlet of the air extraction pipeline is connected to the air extraction pump, and the air extraction valve is arranged in the air extraction pipeline; The calibration mechanism includes a calibration gas pipeline and a calibration gas inlet valve arranged on the calibration gas pipeline. The inlet end of the calibration gas pipeline is connected to an external standard gas source, and the outlet end of the calibration gas pipeline is connected to the inlet pipeline. The outlet end of the calibration gas pipeline is located at the smoke valve. and between filters; The purge mechanism includes a purge pipe, a purge inlet valve and a gas flow controller. The intake valve is set on the purge pipeline, and the gas flow controller is set on the exhaust pipeline; The controlled end of the light source module is connected to the light source control end of the central processing module, the communication end of the spectrum receiving and analysis module is connected to the spectrum analysis communication end of the central processing module, the communication end of the gas flow controller is connected to the flow communication end of the central processing module, and the central processing module pumps air The control end is connected to the controlled end of the air pump. 2. The direct measurement type gaseous pollutant emission monitoring device according to claim 1, characterized in that: the light source module is connected to the detection chamber through a transmitting optical fiber unit, and the spectrum receiving analysis module is connected to the detection chamber through a reflecting optical fiber unit, and the emission The optical fiber unit is arranged between the light source module and the main reflector, and the reflective fiber unit is arranged between the main reflector and the spectrum receiving and analyzing module; the emitting optical fiber unit includes an emitting lens and an emitting light-guiding fiber, and the emitting lens and the emitting light-guiding fiber are arranged along the light source The optical path direction from the module emission to the main reflector is arranged in sequence, and the reflective fiber unit includes a reflective lens and a reflective light-guiding fiber, and the reflective lens and reflective light-guiding fiber are arranged in sequence along the light path direction reflected from the main reflector to the spectrum receiving and analyzing module. 3. The direct measurement gaseous pollutant emission monitoring device according to claim 2, characterized in that: the detection chamber is also provided with a secondary reflector, the secondary reflector is located on the left side of the primary reflector and is opposite to the primary reflector . 4. The direct measurement gaseous pollutant discharge monitoring device according to claim 1 or 2, characterized in that: the detection mechanism also includes a temperature sensor and a pressure sensor arranged in the detection chamber, and the output terminals of the temperature sensor and the pressure sensor Connect the signal input terminals of the spectrum receiving analysis module respectively. 5. The direct measurement gaseous pollutant discharge monitoring device according to claim 1 or 2, characterized in that: it also includes an oxygen detection module arranged on the air extraction pipeline, and the output end of the oxygen detection module is connected to the detection signal input of the central processing module When the detection mechanism detects the content of gas pollutants in the high-temperature sample gas, the oxygen detection module directly detects the oxygen content of the same sample gas, and when the detection mechanism performs standard gas calibration, the standard gas enters the oxygen detection module at the same time The detection module is calibrated. 6. The direct-measurement gaseous pollutant emission monitoring device according to claim 1 or 2, characterized in that: the inlet pipe is provided with a _NOx converter, and the _NOx converter is arranged at the outlet end of the calibration gas pipe and between filters. 7. The direct-measurement gaseous pollutant discharge monitoring device according to claim 1 or 2, characterized in that: the smoke valve adopts a check valve or a long-stem control valve. 8. The direct measurement gaseous pollutant emission monitoring device according to claim 1 or 2, characterized in that: the air pump adopts an air ejector, and the air ejector is provided with a compressed air inlet, a sample gas The suction port and the sample gas outlet, the compressed air inlet is connected to the external air source, the sample gas suction port is connected to the suction pipe, the sample gas outlet is connected to the gas outlet pipe, and the gas outlet pipe is connected to the inside of the flue. 9. The direct measurement gaseous pollutant emission monitoring device according to claim 1 or 2, characterized in that the light emitted by the light source module is ultraviolet light. 10. A direct measurement gaseous pollutant discharge monitoring device according to claim 1 or 2, characterized in that: when calibration gas is used for calibration, the calibration gas inlet valve is opened, the smoke valve is closed, and the calibration gas and the filter cover The flue gas inside is isolated, the flue gas cannot enter the intake pipe and mix with the standard gas, and the standard gas will not leak from the intake pipe into the flue.