Flue gas sampling device adopting dilution method

Abstract

The utility model provides a dilution method flue gas sampling device which comprises a sampling gun, one end of the sampling gun is an open end for sucking flue gas, the other end of the sampling gun is a closed end and is sealed by a sealing plate, the closed end of the sampling gun is provided with a horizontal purging pipe, one end of the purging pipe is provided with an air inlet, and the other end of the purging pipe is provided with an air jet orifice. An air injection opening end of the purging pipe horizontally penetrates through a purging hole formed in the middle of the sealing plate and partially extends into the sampling gun to be suspended, a sampling hole is formed in the upper side wall of the sampling gun and is in sealed connection and communication with a vertically-arranged sampling pipe, a cylindrical flow limiting block is coaxially nested in the sampling pipe, and a vertically-through sound velocity small hole is formed in the flow limiting block in the axis direction; a vacuum generator is arranged at the upper end of the sampling tube, and an air suction port of the vacuum generator is hermetically communicated with the upper end of the sound velocity small hole. The flue gas sampling device is high in flue gas sampling precision in a flue, good in sampling process stability, simple in sampling structure, high in fault detection speed and low in fault rate.

Description

Technical Field

[0001] The utility model relates to the technical field of smoke pollutant detection in thermal power generation, in particular to a dilution method smoke sampling device. Background Art

[0002] In order to conduct environmental testing, the continuous emission monitoring system (CEMS) has been installed and used in large thermal power plants in my country since the 1980s. It has become an indispensable environmental testing equipment for thermal power plants. The monitoring quantities of CEMS in thermal power plants include sulfur dioxide, nitrogen oxides, particulate matter and flue gas parameters (temperature, pressure, flow rate, oxygen content), etc. According to the sampling method, CEMS is divided into three categories: direct extraction, dilution extraction and direct measurement. Compared with the other two methods, the dilution extraction method has the advantages of high measurement accuracy, small sample gas flow rate, and no need for heating of the sampling pipeline. With the completion of domestic ultra-low emissions in the power industry and the implementation of deep ultra-low emissions, the emission indicators of major pollutants are developing towards single digits, and the advantages of high measurement accuracy of the dilution extraction method will be more obvious. However, due to the small size of the core component-the sonic orifice (0.05-2 mm), the dilution extraction flue gas sampling device is prone to blockage caused by dust in the flue gas, and it is not easy to troubleshoot, which is not conducive to the stable operation of CEMS. Utility Model Content

[0003] The utility model provides a dilution method smoke sampling device, which aims to solve the problems of poor sampling process stability, high failure rate and inconvenient fault troubleshooting of the existing dilution extraction type smoke sampling device.

[0004] The utility model is realized by the following technical solutions:

[0005] A dilution method flue gas sampling device comprises a sampling gun, the sampling gun is a horizontally arranged hollow tube, one end of the sampling gun is arranged as an open end for sucking flue gas, and the other end is arranged as a closed end and sealed by a sealing plate, a horizontal purge pipe is arranged at the closed end of the sampling gun, one end of the purge pipe is arranged as an air inlet, and the other end is arranged as an air injection port, the air injection port end of the purge pipe horizontally passes through the purge hole part opened in the middle of the sealing plate and extends into the interior of the sampling gun for suspension, a sampling hole is arranged on the upper side wall of the sampling gun, the sampling hole is sealed and connected to a vertically arranged sampling tube, a cylindrical flow limiting block is coaxially nested in the sampling tube, the flow limiting block is arranged with a sonic small hole penetrating up and down along the axial direction, a secondary filter element is arranged at the lower end of the flow limiting block, a vacuum generator is arranged at the upper end of the sampling tube, the air inlet and the exhaust port of the vacuum generator are respectively located on the left and right sides thereof, the air suction port is located at the bottom of the vacuum generator, and the air suction port of the vacuum generator is sealed and connected with the upper end of the sonic small hole.

[0006] Furthermore, the sampling gun is a hollow round tube or a hollow square tube.

[0007] Furthermore, the air injection port end of the purge pipe is configured to be in a bell-mouth shape, and a solenoid valve is provided on the purge pipe.

[0008] Furthermore, a primary filter element is arranged inside the open end of the sampling gun.

[0009] Furthermore, the sonic orifice comprises an upper conical hole and a lower cylindrical hole connected to the conical hole. The conical hole is a conical hole that is smaller at the top and larger at the bottom. The upper end diameter of the conical hole is 0.05-0.2 mm.

[0010] Furthermore, the sampling gun is vertically arranged on the side wall of the smoke pipe, a mounting hole is provided on the side wall of the smoke pipe, and the sampling end of the sampling gun is partially sealed and inserted into the smoke pipe and fixed therein.

[0011] Furthermore, the air inlet of the vacuum generator is connected to the air compressor through a pipeline, and the exhaust port of the vacuum generator is connected to the gas analyzer through a pipeline.

[0012] Furthermore, a sealing gasket is arranged on the top of the current limiting block, and the sealing gasket is cylindrical. The sealing gasket is coaxially nested inside the sampling tube, and the upper end surface of the sealing gasket is sealed and fixed to the bottom of the vacuum generator. The sealing gasket is provided with a central through hole along the axis, and the central through hole connects the suction port of the vacuum generator with the sonic orifice.

[0013] Furthermore, the lower end portion of the secondary filter element protrudes from the lower end of the sampling tube and extends into the sampling gun.

[0014] Furthermore, a pressure measuring hole 1 is opened on the side wall of the suction channel corresponding to the suction port of the vacuum generator, and the outer end of the pressure measuring hole 1 is connected to a negative pressure gauge 1 through a pressure measuring tube 1; a pressure measuring hole 2 is opened on the inner top wall of the sampling gun, and the outer end of the pressure measuring hole 2 is connected to a negative pressure gauge 2 through a pressure measuring tube 2.

[0015] The beneficial effects of the utility model: the utility model proposes a dilution method flue gas sampling device, which sets a secondary filter element so that the dust will fall back into the sampling gun under the action of gravity, and at the same time, the compressed air is sprayed through the purge pipe to clean the secondary filter element, which further reduces the possibility of dust accumulation in the secondary filter element and the blockage of the sonic holes. The vacuum generator and the sampling gun are subjected to real-time pressure detection through a negative pressure gauge, and the operation and fault conditions of the sampling device can be understood in time through pressure anomalies, which facilitates the troubleshooting of faults. The utility model has high sampling accuracy for the flue gas in the flue, good stability in the sampling process, simple sampling structure, fast fault detection speed and low fault rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic cross-sectional view of the overall structure of the utility model.

[0017] Figure 2 This is a schematic diagram of the sampling principle of the utility model.

[0018] Figure 3 This is a schematic diagram of the purge principle of the utility model.

[0019] Reference numerals:

[0020] 1-sampling gun; 11-sealing plate; 12-purge hole; 13-sampling hole; 14-pressure measuring hole 2; 15-pressure measuring tube 2; 16-negative pressure gauge 2;

[0021] 2-purge pipe; 21-air inlet; 22-air injection port;

[0022] 3- Sampling tube;

[0023] 4-current limiting block; 41-sonic orifice; 411-conical hole; 412-cylindrical hole;

[0024] 5-Secondary filter element;

[0025] 6-vacuum generator; 61-air inlet; 62-exhaust port; 63-intake port; 64-a pressure measuring hole; 65-a pressure measuring tube; 66-a negative pressure gauge;

[0026] 7-First-stage filter element;

[0027] 8-sealing pad; 81-center through hole;

[0028] 9-Solenoid valve

[0029] 10-smoke pipe; 101-installation hole. DETAILED DESCRIPTION

[0030] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific implementation methods.

[0031] Embodiment 1:

[0032] See also Figures 1 to 3A dilution method flue gas sampling device comprises a sampling gun 1, wherein the sampling gun 1 is a horizontally arranged hollow tube, wherein the sampling gun 1 is a hollow round tube or a hollow square tube, preferably a hollow round tube, wherein one end of the sampling gun 1 is arranged as an open end for sucking flue gas, and the other end is arranged as a closed end sealed by a sealing plate 11, wherein a primary filter element 7 is arranged inside the open end of the sampling gun 1, and a horizontal purge pipe 2 is arranged at the closed end of the sampling gun 1, wherein one end of the purge pipe 2 is arranged as an air inlet 21, and the other end is arranged as an air injection port 22, wherein the purge pipe 2 is provided with an air inlet port 21, and the other end is provided as an air injection port 22. The air injection port 22 end of the sweep pipe 2 horizontally passes through the purge hole 12 opened in the middle of the sealing plate 11 and partially extends into the interior of the sampling gun 1 for suspension. The air injection port 22 end of the purge pipe 2 is set in a trumpet shape. The solenoid valve 9 is set on the purge pipe 2. A sampling hole 13 is opened on the upper side wall of the sampling gun 1. The sampling hole 13 is sealed and connected to a vertical sampling tube 3. A cylindrical current limiting block 4 is coaxially nested in the sampling tube 3. The current limiting block 4 is provided with a sonic small hole 41 that passes through from top to bottom along the axial direction. The sonic small hole 4 1 comprises an upper half conical hole 411 and a lower half cylindrical hole 412 connected to the conical hole 411, the conical hole 411 is a conical hole with a small upper part and a large lower part, and the upper end aperture of the conical hole 411 is 0.05-0.2 mm, and a secondary filter element 5 is arranged at the lower end of the flow limiting block 4, and the lower end portion of the secondary filter element 5 protrudes from the lower end of the sampling tube 3 and extends into the sampling gun 1. A sealing gasket 8 is arranged on the upper side of the flow limiting block 4, and the sealing gasket 8 is cylindrical and coaxially nested in the sampling tube 3. The upper end surface of the sealing gasket 8 is sealed and fixed to the bottom of the vacuum generator 6. The sealing gasket 8 is provided with a central through hole 81 along the axis. The central through hole 81 connects the air intake port 63 of the vacuum generator 6 with the sonic hole 41. The vacuum generator 6 is provided at the upper end of the sampling tube 3. The air inlet 61 and the exhaust port 62 of the vacuum generator 6 are respectively located on the left and right sides thereof. The air intake port 63 is located at the bottom of the vacuum generator 6. The air intake port 63 of the vacuum generator 6 is sealed and connected to the upper end of the sonic hole 41.

[0033] A pressure measuring hole 64 is provided on the side wall of the suction channel corresponding to the suction port 63 of the vacuum generator 6, and the outer end of the pressure measuring hole 64 is connected to a negative pressure gauge 66 through a pressure measuring tube 65; a pressure measuring hole 14 is provided on the top wall of the sampling gun 1, and the outer end of the pressure measuring hole 14 is connected to a negative pressure gauge 16 through a pressure measuring tube 15

[0034] When in use, the sampling gun 1 is vertically arranged on the side wall of the smoke pipe 10, and the side wall of the smoke pipe 10 is provided with a mounting hole 101. The sampling end of the sampling gun 1 is partially sealed and inserted into the smoke pipe 10 and fixed from the mounting hole 101. The air inlet 61 of the vacuum generator 6 is connected to the air compressor through a pipeline, and the exhaust port 62 of the vacuum generator 6 is connected to the gas analyzer through a pipeline.

[0035] The vacuum generator 6 provides the power for exhausting air. When compressed air is passed into the vacuum generator 6, a vacuum will be formed inside the vacuum generator 6. Since the gas has the characteristic of spontaneously flowing from high pressure to low pressure, the flue gas will pass through the primary filter element 7, the sampling gun 1, the secondary filter element 5, and the sonic orifice 41 to reach the vacuum generator 6, and after being mixed with the compressed air, it will be sent to the analyzer for analysis.

[0036] Among them, the filtering accuracy of the first-level filter element 7 is about 5 microns, and its main function is to prevent larger dust in the flue gas from entering the sampling gun 1; the filtering progress of the second-level filter element 5 is about 1 micron, and its main function is to prevent smaller dust in the flue gas from entering the sonic hole 41.

[0037] Among them, the interior of the sonic orifice 41 is connected by a conical flow channel and a cylindrical channel, and the diameter at the smallest point is 0.05 to 0.2 mm, preferably 0.1 mm. According to the principle of fluid dynamics, the maximum flow rate of the gas in the reduced orifice is the speed of sound (340 m / s). Therefore, under sufficiently large negative pressure conditions, the extracted flue gas flow rate is a constant value: 340*π*d2 / 4 (d is the minimum pore size, π is pi). This constant flow characteristic is the key to dilution sampling. However, due to the small pore size, even with the presence of a filter element, it is impossible to completely avoid the entry of dust, which leads to blockage of the sonic orifice or vacuum generator. Therefore, the utility model is provided with a purge tube.

[0038] In the above embodiments, see the attached Figure 3 The solenoid valve 9 is opened regularly, and the compressed air for blowing enters along the blowing pipe 2 and diffuses at the bell mouth, cleaning the secondary filter element 5 along the tangential direction.

[0039] In the above embodiment, the secondary filter element 5 is located above the sampling gun, and the gas flow direction in the secondary filter element 5 is perpendicular to the sampling gun 1. On the one hand, the dust attached to the secondary filter element 5 will fall back into the sampling gun 1 under the action of gravity. On the other hand, due to the special setting of the purge tube 2, the compressed air for purge cleans the secondary filter element 5 tangentially, further reducing the possibility of dust accumulation in the secondary filter element 5.

[0040] In the above embodiment, the function of the negative pressure gauge 1 is to monitor the operating state of the vacuum generator 6 in real time. Under normal circumstances, the vacuum degree at the position measured by the negative pressure gauge 1 is about 0.05MPa. If the vacuum generator 6 is blocked or has other faults, the vacuum degree will drop significantly. Therefore, the fault of the vacuum generator 6 can be timely checked through this value. The vacuum generator 6 is composed of a compressed air nozzle and a shell; and its interior is connected to the outside world through a small hole.

[0041] In the above embodiment, the function of the negative pressure gauge 2 is to measure the operating status of the sonic orifice 41 in real time, which reflects the flow rate of the extracted gas. The smaller the flow rate, the smaller the value. It can be understood that under normal circumstances, the vacuum degree at the position measured by the negative pressure gauge 2 is about 3kPa. If the sonic orifice 41 is blocked or other faults occur, the flow rate of the extracted gas will tend to zero, and the value will also drop significantly. Therefore, the fault of the sonic orifice 41 can be reduced by this value.

[0042] Wherein, the vacuum degree measurement range of the negative pressure gauge 1 is 0~0.02MPa;

[0043] Wherein, the vacuum degree measuring range of the negative pressure gauge 2 is 0-10 kPa;

[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A dilution method flue gas sampling device, characterized in that: The sampling gun (1) comprises a sampling gun (1), wherein the sampling gun (1) is a horizontally arranged hollow tube, wherein one end of the sampling gun (1) is arranged as an open end for sucking smoke, and the other end is arranged as a closed end sealed by a sealing plate (11), and a horizontal purge pipe (2) is arranged at the closed end of the sampling gun (1), wherein one end of the purge pipe (2) is arranged as an air inlet (21), and the other end is arranged as an air injection port (22), and the air injection port (22) end of the purge pipe (2) horizontally passes through a purge hole (12) opened in the middle of the sealing plate (11) and partially extends into the interior of the sampling gun (1) to be suspended, and a sampling hole (13) is opened on the upper side wall of the sampling gun (1). The sampling hole (13) is sealed and connected to a vertically placed sampling tube (3). A cylindrical flow limiting block (4) is coaxially nested in the sampling tube (3). The flow limiting block (4) is provided with a sonic hole (41) that passes through the flow limiting block (4) in an axial direction. A secondary filter element (5) is provided at the lower end of the flow limiting block (4). A vacuum generator (6) is provided at the upper end of the sampling tube (3). The air inlet (61) and the air outlet (62) of the vacuum generator (6) are respectively located on the left and right sides thereof. The air intake (63) is located at the bottom of the vacuum generator (6). The air intake (63) of the vacuum generator (6) is sealed and connected to the upper end of the sonic hole (41).

2. A dilution method smoke sampling device as claimed in claim 1, characterized in that: The sampling gun (1) is a hollow round tube or a hollow square tube.

3. A dilution method smoke sampling device as claimed in claim 1, characterized in that: The air injection port (22) end of the purge pipe (2) is arranged in a bell-mouth shape, and a solenoid valve (9) is arranged on the purge pipe (2).

4. A dilution method smoke sampling device as claimed in claim 3, characterized in that: A primary filter element (7) is arranged inside the open end of the sampling gun (1).

5. A dilution method smoke sampling device as claimed in claim 1, characterized in that: The sonic orifice (41) comprises an upper conical hole (411) and a lower cylindrical hole (412) connected to the conical hole (411). The conical hole (411) is a conical hole that is smaller at the top and larger at the bottom. The upper end diameter of the conical hole (411) is 0.05-0.2 mm.

6. A dilution method smoke sampling device as claimed in claim 1, characterized in that: The sampling gun (1) is vertically arranged on the side wall of the smoke pipe (10); a mounting hole (101) is provided on the side wall of the smoke pipe (10); and the sampling end of the sampling gun (1) is partially sealed and inserted into the interior of the smoke pipe (10) through the mounting hole (101) and fixed.

7. A dilution method smoke sampling device as claimed in claim 1, characterized in that: The air inlet (61) of the vacuum generator (6) is connected to the air compressor via a pipeline, and the air outlet (62) of the vacuum generator (6) is connected to the gas analyzer via a pipeline.

8. A dilution method smoke sampling device as claimed in claim 1, characterized in that: A sealing gasket (8) is arranged on the top of the current limiting block (4), and the sealing gasket (8) is cylindrical. The sealing gasket (8) is coaxially nested in the sampling tube (3), and the upper end surface of the sealing gasket (8) is sealed and fixed to the bottom of the vacuum generator (6). The sealing gasket (8) is provided with a central through hole (81) along the axis, and the central through hole (81) connects the suction port (63) of the vacuum generator (6) with the sonic orifice (41).

9. A dilution method smoke sampling device as claimed in claim 1, characterized in that: The lower end portion of the secondary filter element (5) protrudes from the lower end of the sampling tube (3) and extends into the sampling gun (1).

10. A dilution method smoke sampling device as claimed in claim 1, characterized in that: A pressure measuring hole (64) is provided on the side wall of the air intake passage corresponding to the air intake port (63) of the vacuum generator (6), and the outer end of the pressure measuring hole (64) is connected to a negative pressure gauge (66) via a pressure measuring tube (65); a pressure measuring hole (14) is provided on the inner top wall of the sampling gun (1), and the outer end of the pressure measuring hole (14) is connected to a negative pressure gauge (16) via a pressure measuring tube (15).

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