Flue gas sampling probe

Abstract

The utility model relates to an environment monitoring technology, and particularly provides a flue gas sampling probe which comprises a sampling pipe and a filter, the cavity and the sampling pipe are respectively fixed on two sides of the connecting piece and are communicated with each other, and the filter is arranged in the cavity; the bearing part is connected with the cavity, and the filter is fixed on the bearing part; a plurality of gas channels are arranged in the bearing part, and a drainage pump and a first opening are respectively arranged on the bearing part and are communicated with the cavity through the gas channels; the quantifying module, the wet oxygen sensor and the second opening are respectively arranged on the bearing part and are communicated with the downstream of the filter through the gas channel. The device has the advantages of stable dilution ratio and the like, and is applied to flue gas sampling and dilution.

Description

TECHNICAL FIELD

[0001] The utility model relates to environmental protection monitoring, especially relates to flue gas sampling probe. BACKGROUND

[0002] The dilution sampling probe is used for injecting a small amount of flue gas sample gas with tens or hundreds of times of dilution gas to reduce the sample gas dew point, effectively avoid the condensation of acid gas and water vapor, and realize high-fidelity in-situ sampling of flue gas. The diluted sample gas has an extremely low concentration, which ensures the continuous long-term safe and stable operation state of the CEMS system, and reduces the corrosion and erosion of the equipment by the sample gas. For details, refer to patents CN221404938U, CN211825354U, CN2752745Y, CN214408252U and CN118010240A.

[0003] The flue gas extraction technology of CEMS can be divided into direct extraction type and dilution extraction type according to the sampling mode and detection principle, and the direct extraction type can be further divided into cold dry method and hot wet method, the difference between which lies in whether the sample gas is subjected to condensation water removal or whole-process high-temperature heating to avoid condensation. The dilution extraction type can be further divided into flue gas extraction in the flue and flue gas extraction outside the flue, the difference between which lies in whether the dilution component is in the flue or outside the flue. The comparison of the methods is shown in the following table:

[0004]

[0005] At present, coal-fired power plants, steel, cement and many other industries have completed ultra-low emission transformation, and the working conditions are high-humidity, low-temperature and low-concentration. The cold dry method CEMS is difficult to measure accurately due to the instrument principle and large range, and the measurement result is low or even undetectable due to condensation loss. Although there are schemes and products such as phosphoric acid titration and water and ammonia removal on the market, the overall improvement effect is limited, and the actual application effect is not ideal. The hot wet method CEMS also faces many problems such as high temperature requirement of device, complex pretreatment, easy crystallization of ammonium salt, easy aging of optical fiber and inconvenient maintenance.

[0006] For the dilution probe of CEMS, it is important to ensure constant dilution ratio. The core component for ensuring constant dilution ratio is the sonic orifice. When the pressure difference between the two ends of the orifice is greater than 0.46 times, the velocity of the gas flowing through the orifice is basically independent of the pressure change between the two ends of the orifice, but depends on the vibration speed (sonic speed) of the gas molecules flowing through the orifice, that is, a constant flow is generated. Compressed air or nitrogen gas enters the dilution jet pump (hereinafter referred to as dilution pump) as dilution gas, reaches the sonic state in the throat of the dilution pump and generates a large negative pressure, which makes the flue gas in the sonic orifice upstream reach the sonic state and attract the flue gas into the sonic orifice. The sonic critical condition generated by the dilution pump and the sonic orifice can ensure that the sample gas flow and the dilution gas flow remain constant, thus ensuring the constant dilution ratio.

[0007] The sampling pipeline of the dilution system is usually composed of four polytetrafluoroethylene pipes, two of which are used to respectively transport calibration gas and dilution zero air to the sampling probe, one is used to transport the diluted flue gas sample to various analysis instruments, and the other is used to monitor the vacuum degree of the probe part. All the sampling pipelines are under positive pressure except the vacuum pipeline, so as to avoid errors caused by gas leakage.

[0008] The existing sampling probe has the following deficiencies:

[0009] 1. The existing dilution sampling probe basically only completes the flue gas dilution sampling function, and the flue gas transmitted to the system cabinet is already diluted flue gas. The conventional extraction type wet oxygen analyzer is no longer applicable because the principle detection limit cannot meet the requirements, and the trace humidity analyzer (dew point meter) and trace oxygen analyzer have high costs. Therefore, for the measurement of flue gas humidity and flue gas oxygen content of the dilution system, the conventional method is to install an in-situ wet oxygen analyzer on the flue duct. The in-situ wet oxygen analyzer is greatly affected by the working conditions, and is not suitable for some harsh working conditions such as high temperature, high humidity and high dust, and is inconvenient to operate in terms of calibration and maintenance.

[0010] 2. The existing dilution sampling probe basically only monitors the vacuum degree at the rear end of the sonic orifice, and if the working negative pressure is large, the same vacuum degree may not meet the constant flow condition of the sonic orifice, and the dilution ratio cannot be guaranteed to be stable.

[0011] 3. The existing dilution sampling probe basically determines the dilution ratio through the structure of the dilution jet pump and the aperture of the sonic orifice, and the dilution ratio is fixed under the condition that the structure does not change, which may not be suitable for different concentration conditions.

[0012] 4. The existing dilution sampling probe needs four polytetrafluoroethylene pipes to connect with the station building, and the back flushing gas and the calibration gas share one pipe. The industry standard requires that the calibration gas should pass to the outside of the probe filter, so that the back flushing gas can only flush the outside of the filter, and the back flushing effect is not good.

[0013] 5. Because the sampling flow of the dilution sampling probe is small, only about 100 ml / min, and the sampling probe rod and the filter cavity are large before dilution, if the flue gas is not pre-extracted to the front of the sonic orifice, the response lag is serious. The existing scheme requires compressed air for both the drainage pump and the dilution pump, and the air consumption is large.

[0014] 6. The existing dilution sampling probe needs to be matched with a manual or electric valve group at the system cabinet end to realize the back flushing and calibration functions. The pipeline between the probe and the system cabinet is long, there is a lot of residual calibration gas in the calibration pipeline after the calibration gas is introduced, the data is stable slowly after the system is switched to the normal measurement state, and a long time is needed to reflect the real concentration of the working condition. SUMMARY

[0015] To solve the deficiencies in the prior art, the present application provides a flue gas sampling probe.

[0016] The utility model discloses a purpose is realized through the following technical schemes:

[0017] A flue gas sampling probe, including sampling pipe, filter, the flue gas sampling probe still includes:

[0018] Cavity and connecting piece, the cavity and sampling pipe are fixed respectively at both sides of connecting piece, and communicate, the filter is arranged in the cavity,

[0019] Bearing, the bearing is connected the cavity, and the filter is fixed on the bearing,

[0020] Multiple gas passages are arranged in the bearing, and the drainage pump and the first opening are arranged on the bearing respectively and communicate the cavity through the gas passage, and the quantitative module, the wet oxygen sensor and the second opening are arranged on the bearing respectively and communicate the downstream of the filter through the gas passage.

[0021] Compared with the prior art, the utility model has the beneficial effects that:

[0022] 1. simple structure,

[0023] By arranging multiple gas passages in the bearing, calibration gas, back flushing gas, drainage gas and sample gas pass through, and at the same time, the wet oxygen sensor, the drainage pump and the quantitative module are installed on the bearing, so that the functions of drainage, wet oxygen detection, back flushing, calibration and sampling are realized on the bearing, and the structural complexity is reduced.

[0024] 2. stable dilution ratio, convenient adjustment,

[0025] The openings are arranged respectively at the upstream and downstream of the sonic hole, and the pressures are obtained respectively by using the openings, so that whether the sample gas passes through the sonic hole at the sonic speed is known in real time, the sample gas flow is ensured to be stable, and the dilution ratio of the (jet pump) is ensured to be stable.

[0026] In view of the stable sample gas flow, the dilution ratio is accurately adjusted by adjusting the entraining gas flow of the jet pump.

[0027] 3. compatible with self-flow and drainage,

[0028] In the working condition that the flue gas flow rate is high, the second through hole is opened, the inclined cut of the end of the sampling pipe faces the airflow, under the action of the flue gas dynamic pressure, the flue gas passes through the sampling pipe, the cavity and the second through hole in turn and returns to the flue duct without starting the drainage pump, and the gas consumption of the system is reduced.

[0029] In the working condition that the flue gas flow rate is low, the flue gas dynamic pressure is weak, the second through hole is blocked, the first through hole is opened, and the flue gas passes through the sampling pipe, the cavity, the gas passage, the drainage pump and the first through hole in turn under the action of the negative pressure of the drainage pump and returns to the flue duct.

[0030] 4. Switching time is short;

[0031] The pipeline is short, such as the interval between the outlet of the drainage pump and the first through hole, the interval between the fifth gas passage and the sonic hole, and data is stable soon after switching back to the measurement state from other states. BRIEF DESCRIPTION OF DRAWINGS

[0032] The disclosure of the present application will become more readily understood by reference to the accompanying drawings. It will be readily understood to those skilled in the art that the drawings are not intended to limit the present application, and that the present application is capable of further embodiments and is capable of being practiced or being carried out in various ways. In the drawings:

[0033] Figure 1 is a structural schematic diagram of a flue gas sampling probe according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] Figure 1 The following description describes optional specific embodiments of the present application to teach those skilled in the art how to implement and reproduce the present application. Some conventional aspects have been simplified or omitted in order to explain the technical solutions of the present application. Those skilled in the art should understand that variations or substitutions derived from these specific embodiments will be within the scope of the present application. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the present application. Therefore, the present application is not limited to the following optional specific embodiments, but is defined only by the claims and their equivalents.

[0035] Example 1:

[0036] The flue gas sampling probe according to an embodiment of the present application, as shown in Figure 1 , comprises:

[0037] The sampling tube 17 and the filter 13 are both prior art in the field.

[0038] The cavity 18 and the sampling tube 17 are fixed on both sides of the connecting piece 22 and are in communication, and the filter 13 is arranged in the cavity 18.

[0039] The carrier 20 is connected to the cavity 18, and the filter 13 is fixed on the carrier 20.

[0040] A plurality of gas passages are arranged in the carrier 20, the drainage pump 8 and the first opening 7 are arranged on the carrier 20 and are in communication with the cavity 18 through the gas passages, and the dosing module, the wet oxygen sensor 6 and the second opening 11 are arranged on the carrier 20 and are in communication with the downstream of the filter 13 through the gas passages.

[0041] In order to monitor whether the sample gas passes through the sonic orifice at the sound velocity in real time, further, a third opening 5 is arranged on the bearing 20 and communicates with the gas passage upstream of the dosing module, and a fourth opening 4 is arranged on the pipeline downstream of the dosing module;

[0042] The pressure sensor respectively communicates with the third opening 5 and the fourth opening 4.

[0043] In order to be compatible with the self-flow and the flow-lead scheme, further, a first through hole 15 is arranged on the connecting piece 22 outside the cavity 18, and the outlet of the flow-lead pump 8 communicates with the first through hole 15, and the flue gas in the flue sequentially passes through the sampling pipe 17, the cavity 18, the gas passage, the flow-lead pump 8 and the first through hole 15, and returns to the flue.

[0044] In order to effectively utilize the dynamic pressure of the flue gas to realize the self-flow, further, the cut of the end of the sampling pipe 17 in the flue is opposite to the flue gas flow direction, and a second through hole 14 is arranged on the connecting piece 22 inside the cavity 18, and the flue gas in the flue sequentially passes through the sampling pipe 17, the cavity 18 and the second through hole 14, and returns to the flue.

[0045] In order to realize the functions of air extraction and dilution, further, the dosing module comprises the sonic orifice 21 and the jet pump 1, and the fourth opening 4 is arranged on the pipeline between the sonic orifice 21 and the jet pump 1.

[0046] In order to realize the calibration function, further, the calibration gas passing through the first inlet opening 7 sequentially passes through the gas passage, the cavity 18, the filter 13, the gas passage and the dosing module.

[0047] In order to prevent the flue gas from condensing and realize the installation, further, the flue gas sampling probe further comprises:

[0048] A heating unit 12 is arranged for heating the gas in the cavity 18;

[0049] A flange 16 is arranged, the sampling pipe 17 is arranged in the flange 16, and the connecting piece 22 is fixed on the flange 16 and seals the open end of the flange 16.

[0050] Embodiment 2:

[0051] The application example of the flue gas sampling probe according to the embodiment 1 in the flue gas monitoring.

[0052] In the application example, as Figure 1As shown, the flange 16 is fixed on the wall of the flue, the sampling tube 17 is of telescopic sleeve structure, and the end part has an inclined cut. Part of the sampling tube 17 is arranged in the flange 16. The connecting piece 22 in the shape of a disc seals the open end of the flange 16, and the sampling tube 17 and the cavity 18 are fixed on the two sides of the connecting piece 22 and are communicated. The first through hole 15 is arranged on the connecting piece 22 outside the cavity 18 and is used for communicating the inside and outside of the flue. The second through hole 14 is arranged on the connecting piece 22 inside the cavity 18 and is used for communicating the flue and the cavity 18.

[0053] The heating unit 12 such as a heating sleeve is arranged outside the cavity 18 and is used for heating the flue gas in the cavity 18.

[0054] The carrier 20 is connected to the cavity 18, and the sealing gasket 19 is arranged therebetween. Six straight gas channels are arranged in the carrier 20, the first gas channel penetrates through the carrier 20, the filter 13 is arranged at the inlet of the first gas channel, the wet oxygen sensor 6 is fixed on the carrier 20 and extends into the first gas channel. The central axis of the first gas channel is collinear with the central axis of the sampling tube 17.

[0055] The second gas channel penetrates through the carrier 20 and is communicated with the cavity 18 at one end and the first opening 7 at the other end. The first opening 7 is communicated with the calibration gas. The second gas channel is arranged in parallel with the first gas channel but is not directly communicated. The third gas channel is directly communicated with the second gas channel, the drainage pump 8 is fixed on the carrier 20 and is a jet pump, one inlet is the compressed air port 10, the other inlet is communicated with the third gas channel, and the drainage outlet 9 is communicated with the first through hole 15 through a pipeline.

[0056] The fourth gas channel and the fifth gas channel are directly communicated with the first gas channel respectively, and the back flushing gas is communicated with the fourth gas channel through the second opening 11.

[0057] The quantitative module includes the sonic orifice 21 and the jet pump 1. The sonic orifice 21 is arranged on the carrier 20 and is communicated with the fifth gas channel. The fourth opening 4 is arranged on the pipeline between the sonic orifice 21 and the jet pump 1. The third opening is arranged on the carrier 20 and passes through the sixth gas channel. The sixth gas channel is directly communicated with the fifth gas channel, and the pressure at the third opening 5 (fifth gas channel) is obtained by using the pressure sensor. One inlet of the jet pump 1 is the zero air port 2, the other inlet is communicated with the sonic orifice 21, and the outlet is the sample gas outlet after dilution 3.

[0058] Among the above six gas channels, the included angle between the directly communicated gas channels is 90 degrees.

[0059] The working mode of the flue gas sampling probe in the embodiment is as follows:

[0060] The sampling stage.

[0061] In the condition of high flue gas flow rate, the second through hole 14 is opened, the oblique cut of the end of the sampling tube 17 faces the airflow, and the flue gas passes through the sampling tube 17, the cavity 18 and the second through hole 14 in turn under the action of the dynamic pressure of the flue gas, and returns to the flue without starting the drainage pump 8, thereby reducing the gas consumption of the system.

[0062] In the condition of low flue gas flow rate, the dynamic pressure of the flue gas is weak, the second through hole 14 is blocked, the first through hole 15 is opened, and the flue gas passes through the sampling tube 17, the cavity 18, the second gas passage, the third gas passage, the drainage pump 8 and the first through hole 15 (without passing through the first gas passage) in turn under the negative pressure of the drainage pump 8, and returns to the flue.

[0063] The jet pump 1 works, and the flue gas in the cavity 18 passes through the filter 13, the first gas passage, the fifth gas passage, the sonic hole 21 and the jet pump 1 in turn, mixes the zero air from the zero air inlet 2, and the diluted flue gas is discharged from the sample gas outlet 3.

[0064] In the working of the jet pump 1, the pressures at the fourth opening 4 and the third opening 5, i.e. the gas pressures upstream and downstream of the sonic hole 21, are obtained in real time, so as to know whether the flue gas passes through the sonic hole 21 at the sonic speed. If not, the suction of the jet pump 1 is increased.

[0065] Back flushing stage.

[0066] The high-pressure back flushing gas passes through the second opening 11, the fourth gas passage and the first gas passage in turn, back flushes the filter 13, and realizes the cleaning of the filter 13.

[0067] Calibration stage.

[0068] The zero gas or the standard gas passes through the first opening 7, the second gas passage, the cavity 18, the first gas passage, the fifth gas passage, the sonic hole 21 and the jet pump 1 in turn, and is finally discharged from the sample gas outlet 3 to be sent to the downstream analysis instrument, so as to obtain the calibration coefficient by using the output structure of the analysis instrument and the nominal value of the standard gas.

[0069] As can be seen, the filter, the drainage, the dilution, the calibration, the back flushing and the wet oxygen detection are realized by using the carrier.

Claims

1. A flue gas sampling probe comprising a sampling tube, a filter; characterized in that, The flue gas sampling probe further comprises: a cavity and a connecting piece, the cavity and the sampling tube are fixed on two sides of the connecting piece respectively and are communicated, and the filter is arranged in the cavity; a carrier, the carrier is connected to the cavity, and the filter is fixed on the carrier; a plurality of gas passages are arranged in the carrier, the drainage pump and the first opening are arranged on the carrier and are communicated with the cavity through the gas passages, the quantitative module, the wet oxygen sensor and the second opening are arranged on the carrier and are communicated with the downstream of the filter through the gas passages.

2. The smoke gas sampling probe of claim 1, wherein, a third opening is arranged on the carrier and is communicated with the gas passage upstream of the quantitative module, and a fourth opening is arranged on the pipeline downstream of the quantitative module; the pressure sensor is communicated with the third opening and the fourth opening respectively.

3. The smoke gas sampling probe of claim 1, wherein, A first through hole is arranged on the connecting piece outside the cavity, the outlet of the drainage pump is communicated with the first through hole, and the flue gas in the flue passes through the sampling tube, the cavity, the gas passage, the drainage pump and the first through hole in sequence and returns to the flue.

4. The smoke gas sampling probe of claim 1, wherein, An inclined cut of the end of the sampling tube in the flue is arranged to face the direction of the flue gas flow, a second through hole is arranged on the connecting piece inside the cavity, and the flue gas in the flue passes through the sampling tube, the cavity and the second through hole in sequence and returns to the flue.

5. The smoke gas sampling probe of claim 2, wherein, The quantitative module comprises a sonic orifice and a jet pump, and the fourth opening is arranged on the pipeline between the sonic orifice and the jet pump.

6. The smoke gas sampling probe of claim 1, wherein, The calibration gas passing through the first opening passes through the gas passage, the cavity, the filter, the gas passage and the quantitative module in sequence.

7. The smoke gas sampling probe of claim 1, wherein, The flue gas sampling probe further comprises: a heating unit for heating the gas in the cavity; a flange, the sampling tube is arranged in the flange, and the connecting piece is fixed on the flange and seals the open end of the flange.

8. The smoke gas sampling probe of claim 1, wherein, Linear first, second, third, fourth, fifth and sixth gas passages are arranged in the carrier, the drainage pump is communicated with the third gas passage, the second gas passage and the cavity in sequence, the first opening is communicated with the second gas passage and the cavity in sequence, the filter is fixed at the inlet of the first gas passage, the second opening is communicated with the fourth gas passage and the first gas passage in sequence, the wet oxygen sensor is communicated with the first gas passage, the quantitative module is communicated with the fifth gas passage and the first gas passage in sequence, and the pressure sensor is communicated with the sixth gas passage, the fifth gas passage and the first gas passage in sequence.

9. The smoke gas sampling probe of claim 8, wherein, The included angle between the directly communicated gas passages is 90 degrees, and the central axes of the first gas passage, the second gas passage and the sampling tube are parallel.

10. The smoke gas sampling probe of claim 9, wherein, The sampling tube adopts a sleeve.

Images