CN108254581B - Gaseous pollutant multi-point automatic sampling test system - Google Patents

Abstract

The system comprises a plurality of sampling probes, a sample gas pipeline, a rotary automatic switching device, a pretreatment device, a smoke analyzer, an air pump, a compressed air back-flushing device and a three-way valve; the sampling probes are distributed in a matrix form in the flue in the direction opposite to the flue flow direction, the rotary automatic switching device can circularly switch and select the sample gas of the sampling probes at different points in the flue to enter a flue gas analyzer, and a pretreatment device is arranged in front of the flue gas analyzer to dehumidify and dust the sample gas; other sampling probe sample gas enters a bypass air chamber of the rotary automatic switching device and is discharged through an air pump; in order to prevent the sampling port of the sampling probe and the sampling gas pipeline from being blocked, a compressed air back-blowing device is periodically adopted to back-blow the sampling gas pipeline and the sampling probe through a bypass gas chamber of the automatic sampling gas switching device; the invention can be used for on-line continuous monitoring and on-site test, and can accurately grasp the distribution condition of the concentration field of the gaseous pollutant on the measuring section of the flue, thereby greatly improving the representativeness, the accuracy and the working efficiency of the test data.

Description

A multi-point automatic sampling and testing system for gaseous pollutants

Technical field

The invention relates to the technical field of gaseous pollutant testing, and in particular to a multi-point automatic sampling and testing system for gaseous pollutants.

technical background

According to the requirements of the "Huanfa [2015] No. 164 Notice on Issuing the "Comprehensive Implementation of Ultra-Low Emission and Energy-saving Renovation Work Plan for Coal-fired Power Plants" jointly issued by the National Development and Reform Commission, the Ministry of Environmental Protection, and the National Energy Administration, so far the country has completed Ultra-low emission transformation work for more than 60% of coal-fired power plants. Online monitoring of pollutants in flue gas is mostly set up at a single point. The test data is greatly affected by the operation of environmental protection facilities and the location of the measuring point, the cross-sectional area of the flue, the flow field in the flue, and the concentration field. The test data cannot effectively reflect the real operating performance of environmental protection facilities. , which is not conducive to operational adjustment and data analysis. When performing performance tests on site, a set of flue gas analyzers and a set of sample gas sampling tubes are often used to move and switch to multi-point measurements. This requires frequent movement or replacement of sampling positions, which results in a large operating workload and a long test duration.

Contents of the invention

The purpose of the present invention is to solve the above technical problems of online monitoring and on-site testing and provide a multi-point automatic sampling and testing system for gaseous pollutants. It can be used for online continuous monitoring to accurately grasp the distribution of gaseous pollutant concentration fields in the flue, which facilitates the operation and adjustment of environmental protection devices. It can also be used for field trials and tests, greatly improving the representativeness, accuracy and work efficiency of test data.

In order to achieve the above objectives, the present invention adopts the following technical solutions:

A multi-point automatic sampling and testing system for gaseous pollutants, including several sampling probes 2 and corresponding sample gas pipelines 3, a rotary automatic switching device 4, a pretreatment device 5, a flue gas analyzer 6, an air extraction pump 8, a compressed air return Blowing device 7 and three-way plug valve 9; the sampling probe 2 is distributed in a matrix in the direction of the flue gas flow on the measurement section in the flue 1, and the rotary automatic switching device 4 can automatically switch to select a sampling probe at different points. The sample gas of 2 enters the flue gas analyzer 6 through the sample gas pipeline 3. In front of the flue gas analyzer 6, there is a pretreatment device 5 for dehumidification and dust removal of the sample gas; other sampling probes 2 pass through the rotary automatic switching device 4. The bypass air chamber 12 and the three-way plug valve 9 are connected to the air extraction pump 8 and the compressed air backflush device 7 respectively. The sample gas from other sampling probes 2 enters the bypass air chamber 12 of the rotary automatic switching device 4 and passes through the air extraction pump 8 Discharge; in order to prevent the sampling port of the sampling probe 2 and the sample gas pipeline 3 from being blocked, a compressed air backflush device 7 is provided to periodically backflush the sample gas pipeline 3 and the sampling probe 2 through the bypass air chamber 12 of the rotary automatic switching device 4.

The rotary automatic switching device 4 includes a fixed end 15 and a rotary selection end 14 that is rotatably arranged on the fixed end 15. The fixed end 15 is provided with a sample gas pipeline interface 10, and the rotary selection end 14 is provided with a rotary selection end 14. A sample gas selection interface 11, a bypass gas chamber 12 and a bypass interface 13 are connected to a sample gas pipeline interface 10.

The flue 1 is square or circular, and the spacing between the sampling probes 2 is 60 to 100 cm depending on the cross-sectional area of the flue.

The sampling probe 2 and the sample gas pipeline 3 are provided with a heating system, and the heating temperature is not lower than 120°C.

Compared with the prior art, the present invention has the following advantages:

Online monitoring of pollutants in flue gas is mostly set up at a single point. The test data is greatly affected by the operation of environmental protection facilities and the location of the measuring point, the cross-sectional area of the flue, the flow field in the flue, and the concentration field. The test data cannot effectively reflect the real operating performance of environmental protection facilities. , which is not conducive to operational adjustment and data analysis. When performing performance tests on site, a set of flue gas analyzers and a set of sample gas sampling tubes are often used to move and switch to multi-point measurements. This requires frequent movement or replacement of sampling positions, which results in a large operating workload and a long test duration. The invention can be used for online continuous monitoring to accurately grasp the distribution of gaseous pollutant concentration fields in the flue, which facilitates the operation and adjustment of environmental protection devices. It can also be used for on-site testing to greatly improve the representativeness, accuracy and work efficiency of test data.

Description of the drawings

Figure 1 is a schematic structural diagram of the present invention.

Figure 2 is a schematic structural diagram of the rotary automatic switching device, where: Figure 2a is a schematic side view, Figure 2b is a view from the fixed end A-A, and Figure 2c is a view from the rotation selection end B-B.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and examples.

As shown in Figure 1, a multi-point automatic sampling and testing system for gaseous pollutants of the present invention includes several sampling probes 2, sample gas pipelines 3, rotary automatic switching device 4, pretreatment device 5, flue gas analyzer 6, Air pump 8, compressed air backflush device 7 and three-way plug valve 9, etc. The sampling probes 2 are distributed in a matrix in the direction of the flue gas flow on the measurement section in the flue 1. The rotary automatic switching device 4 can automatically switch and select a sampling probe 2 at different positions. The sample gas enters the flue gas analyzer 6. The flue gas A pretreatment device 5 is set up in front of the analyzer 6 to dehumidify and remove dust from the sample gas; the sample gas from other sampling probes 2 enters the bypass air chamber 12 of the rotary automatic switching device 5 and is discharged through the air extraction pump 8 .

As shown in FIG. 2 , the rotary automatic switching device 4 includes a fixed end 15 and a rotary selection end 14 . The fixed end 9 is provided with a sample gas pipeline interface 10, and the rotary selection end 14 is provided with a sample gas selection interface 11, a bypass gas chamber 12 and a bypass interface 13.

In order to prevent the sampling probe 2 and the sample gas pipeline 3 from being blocked, a compressed air backflush device 7 is set up. The compressed air is switched by the three-way plug valve and enters the bypass air chamber of the rotary automatic switching device to perform regular backflush on the sample gas pipeline and the sampling probe. blow.

In order to prevent the gaseous pollutants in the flue gas from dissolving in the condensed water during the sampling process, the sampling probe 2 and the sample gas pipeline 3 are equipped with a heating system, and the heating temperature is not lower than 120°C.

As a preferred embodiment of the present invention, the sampling probes 2 are distributed in a matrix in the flue 1, and the spacing between the sampling probes 2 is 60 to 100 cm depending on the cross-sectional area of the flue.

Claims (2)

1. A multi-point automatic sampling and testing system for gaseous pollutants, including several sampling probes (2) and corresponding sample gas pipelines (3), a rotary automatic switching device (4), a pretreatment device (5), and flue gas analysis instrument (6), air pump (8), compressed air backflush device (7) and three-way plug valve (9); it is characterized in that: the sampling probe (2) is on the measurement section in the flue (1) The reverse flue gas flow direction is distributed in a matrix, and the rotary automatic switching device (4) can automatically switch and select a sampling probe (2) at different points. The sample gas enters the flue gas analyzer (6) through the sample gas pipe (3). A pretreatment device (5) for dehumidifying and dusting the sample gas is provided in front of the flue gas analyzer (6); other sampling probes (2) pass through the bypass air chamber (12) of the rotary automatic switching device (4) and The three-way plug valve (9) is connected to the air extraction pump (8) and the compressed air backflush device (7) respectively, and the sample gas from other sampling probes (2) enters the bypass air chamber (12) of the rotary automatic switching device (4) ), discharged through the air pump (8); in order to prevent the sampling port of the sampling probe (2) and the sample gas pipeline (3) from being blocked, a compressed air backflush device (7) is set up to bypass the rotary automatic switching device (4) regularly The air chamber (12) backflushes the sample gas pipeline (3) and the sampling probe (2); The rotary automatic switching device (4) includes a fixed end (15) and a rotary selection end (14) rotatably provided on the fixed end (15). The fixed end (15) is provided with a sample gas pipeline interface (10). The rotary selection end (14) is provided with a sample gas selection interface (11) connected to a sample gas pipeline interface (10) through the rotary selection end (14), as well as a bypass air chamber (12) and a bypass interface (13); The sampling probe (2) and the sample gas pipeline (3) are provided with a heating system, and the heating temperature is not lower than 120°C. 2. A multi-point automatic sampling and testing system for gaseous pollutants according to claim 1, characterized in that: the flue (1) is square or circular, and the sampling probe (2) is configured according to the cross-sectional area of the flue. ) distance is 60 to 100cm.