JP6468004B2 - Gas sampling device - Google Patents

Description

  The present invention relates to a gas sampling device.

  A denitration apparatus for denitrating nitrogen oxide (NOx) from exhaust gas such as a boiler is known. Such a denitration apparatus injects ammonia gas into the exhaust gas, mixes the exhaust gas and ammonia gas, and reduces the mixture gas to nitrogen gas and water vapor by bringing the mixed gas into contact with the denitration catalyst.

  In order to perform such injection of ammonia gas without excess or deficiency, for example, a part of the exhaust gas is collected in the exhaust gas flow path (flue) on the outlet side of the denitration device, and the ammonia amount (concentration) contained in this is collected. It is necessary to measure with high accuracy (Patent Documents 1 and 2).

JP 2004-117271 A JP-A-9-000871

  By the way, the ammonia amount (concentration) in the exhaust gas passage on the outlet side of the denitration apparatus varies depending on the position in the exhaust gas passage. For this reason, in the technique of Patent Document 1, it is necessary to install probes for analyzing exhaust gas at a plurality of positions in the exhaust gas flow path, calculate the ammonia amount (concentration), and calculate the average value. For this reason, the number of installation of the analysis probe itself or the number of installation steps of the analysis probe and the analyzer increases.

  In the technique of Patent Document 2, the gas sampling pipe (gas sampling pipe) for the NOx concentration meter at the outlet of the NOx removal device is taken out from each of the A and B systems, and a switching valve is provided in the middle. (1) From both the A and B systems Means for sampling and measuring A and B system average outlet NOx concentration values (analyzer), (2) Means for measuring outlet NOx concentration only for A system (analyzer), (3) Outlet NOx concentration only for B system Have a means to measure (analyzer). According to the technique of Patent Document 2, the means (analyzer) for measuring the NOx concentration value increases for each system and each average outlet.

  The present invention has been made in view of the above, and an object of the present invention is to provide a gas sampling device that takes in exhaust gas by alleviating variation in gas components contained in the exhaust gas in the flue.

  In order to solve the above-described problems and achieve the object, the gas sampling device is disposed in the exhaust gas flow path, and is disposed in the exhaust gas flow path, and a plurality of gas sampling pipes for introducing the exhaust gas flowing through the exhaust gas flow path. A mixing pipe for mixing the exhaust gas flowing in from the plurality of gas sampling pipes as exhaust gas for analysis inside, and a flow rate adjusting mechanism for adjusting the pressure of the exhaust gas flowing in from the gas sampling pipe in the mixing pipe, Prepare.

  As a result, the gas sampling device can take in the exhaust gas while reducing variations in the gas components contained in the exhaust gas in the flue.

  As a preferred aspect of the present invention, the flow rate adjusting mechanism includes a shaft having a valve body at a tip inserted into the mixing pipe, and the valve body forms an orifice between the opening of the gas sampling pipe. Preferably it is.

  The gas sampling device can adjust the flow rate of the exhaust gas for each gas sampling tube depending on the position of the valve body inside the mixing tube. For this reason, it is not necessary to adjust the flow rate outside the exhaust gas flow path where the temperature is low, and the compounds generated due to the decrease in temperature are suppressed. As a result, the exhaust gas for analysis in the mixing tube has a small error in the gas component to be measured.

  As a desirable mode of the present invention, it is preferable that the shaft includes a through hole penetrating the inside in a direction parallel to the central axis. Thereby, the flow volume of the exhaust gas in each gas sampling pipe can be easily measured.

  As a desirable aspect of the present invention, it is preferable that the flow rate adjusting mechanism is capable of adjusting the pressure of the exhaust gas flowing from the gas sampling pipe from the outside of the exhaust gas passage. Thereby, the flow volume of a gas sampling pipe | tube can be adjusted easily from the exterior of an exhaust gas flow path.

  As a desirable aspect of the present invention, it is preferable to analyze a liquid in which the exhaust gas for analysis is absorbed. Thereby, the number of installation of the analysis probe itself or the number of installation steps of the analysis probe and the analyzer is suppressed.

  As a desirable aspect of the present invention, it is preferable to include a light emitting unit that emits measurement light and a light receiving unit that receives the measurement light that has passed through the exhaust gas for analysis. Thereby, the gas component which should be measured with respect to the exhaust gas for analysis is measured, without collecting a part of exhaust gas out of the exhaust gas flow path.

  ADVANTAGE OF THE INVENTION According to this invention, the gas sampling apparatus which eases the dispersion | variation in the gas component which the waste gas in a flue contains, and takes in waste gas can be provided.

FIG. 1 is a schematic diagram showing a gas sampling device according to this embodiment. FIG. 2 is a schematic diagram showing a gas sampling device according to the present embodiment. FIG. 3 is a schematic diagram of a III-III ′ cross section in FIG. 1. FIG. 4 is a schematic diagram showing the inside of the mixing tube during cleaning. FIG. 5 is a schematic diagram showing the inside of the mixing tube during cleaning. FIG. 6 is a schematic diagram showing a gas sampling device according to a modification of the present embodiment. FIG. 7 is a schematic diagram of a VII-VII ′ cross section in FIG. 6. FIG. 8 is a schematic diagram of a VIII-VIII ′ cross section in FIG. 6.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

  1 and 2 are schematic views showing a gas sampling device according to this embodiment. FIG. 1 is a diagram schematically illustrating the gas sampling device 1 with a cross section obtained by cutting the exhaust gas flow channel 91 along a plane orthogonal to the flow direction G of the exhaust gas V. FIG. 2 is a diagram schematically illustrating the gas sampling device 1 with a cross section obtained by cutting the exhaust gas flow channel 91 along a plane parallel to the flow direction G of the exhaust gas V. The gas sampling device 1 is a device that collects the exhaust gas V from an exhaust gas passage 91 through which the exhaust gas V flows in order to measure the amount (concentration) of ammonia contained in the exhaust gas V of, for example, a thermal power plant. As shown in FIG. 1, the gas sampling device 1 is fixed to a flow path wall 90 (a flue) of an exhaust gas flow path 91.

As shown in FIG. 2, a denitration device 92 is used to remove nitrogen oxides (NOx) contained in the exhaust gas V flowing inside the exhaust gas passage 91. The denitration device 92 decomposes nitrogen oxide (NOx) into nitrogen (N ₂ ) and water (H ₂ O) by injecting ammonia (NH ₃ ) into the exhaust gas and bringing it into contact with the catalyst.

Part of the ammonia injected into the exhaust gas V by the denitration device 92 may pass through the catalyst without reacting with nitrogen oxides. Ammonia (unreacted ammonia) contained in the exhaust gas V that has passed through the denitration device 92 reacts with sulfur oxide (SOx) contained in the exhaust gas V to generate ammonium hydrogen sulfate (NH ₄ HSO ₄ ). The produced acidic ammonium sulfate may block an air heater disposed downstream of the denitration device 92. For this reason, in order to operate the thermal power plant smoothly, it is necessary to grasp the ammonia amount (concentration) contained in the exhaust gas V that has passed through the denitration device 92.

  As shown in FIG. 2, the gas sampling device 1 includes a plurality of gas sampling tubes 6, a mixing tube 4, an analysis probe outer tube 3, an analysis probe inner tube 2, a transport tube 23, and an absorption bottle 13. A connecting pipe 24, a suction pump 14, a connecting pipe 25, a gas meter 15, an introduction pipe 21, a cleaning liquid pump 11, a connecting pipe 22, and a cleaning liquid bottle 12. The analysis probe according to the present embodiment includes an analysis probe outer tube 3 and an analysis probe inner tube 2.

  As shown in FIG. 1, the plurality of gas sampling tubes 6 communicate with the inside of the mixing tube 4. The gas sampling pipe 6 is a hollow member in which an opening 61A at one end is disposed inside the exhaust gas passage 91 and an opening 61B (see FIG. 3) at the other end is disposed inside the mixing pipe 4. Depending on the position of the mixing tube 4, the gas sampling tube 6 has a curved portion 61R and may be curved. When the curvature of the curved portion 61R is small (the radius of curvature is large), dust is difficult to collect and cleaning is easy. When the material of the gas sampling tube 6 and the material of the mixing tube 4 are, for example, iron or stainless steel, durability at high temperatures can be improved. When the material of the gas sampling tube 6 and the material of the mixing tube 4 are iron or stainless steel, it is preferable to coat the inner surfaces of the gas sampling tube 6 and the mixing tube 4 with aluminum or ceramic. Thereby, the molybdenum, tungsten, vanadium, chromium, manganese, iron, cobalt, nickel, platinum, etc. which iron or stainless steel contains are not made to contact with the exhaust gas V which extract | collected. For this reason, the reaction between the gas sampling pipe 6 or the mixing pipe 4 and the ammonia contained in the exhaust gas V is suppressed. More preferably, the outer surfaces of the gas sampling tube 6 and the mixing tube 4 are coated with aluminum or ceramic. Alternatively, when the material of the gas sampling tube 6 and the material of the mixing tube 4 are titanium, durability at high temperatures is increased, and the reaction between the gas sampling tube 6 or the mixing tube 4 and ammonia is suppressed.

  As shown in FIG. 1, a plurality of openings 61 </ b> A of the gas sampling pipe 6 are arranged in a cross section obtained by cutting the exhaust gas flow channel 91 by a plane orthogonal to the flow direction G of the exhaust gas V (hereinafter referred to as a measurement plane). The

  The ammonia amount (concentration) in the exhaust gas passage 91 on the outlet side of the denitration device 92 (see FIG. 2) may vary in the flue. However, in the measurement plane of the present embodiment, when the exhaust gas V collected from the openings 61A of the plurality of gas sampling tubes 6 is mixed inside the mixing tube 4, the ammonia amount (concentration) in the measurement plane is averaged. . As a result, the influence of variations in the ammonia amount (concentration) in the flue is reduced, and if the exhaust gas inside the mixing tube 4 is used as an exhaust gas for analysis, the accuracy in measuring the ammonia amount (concentration) is increased.

  Thus, the mixing pipe 4 is a flow path connected to the gas sampling device 1 and mixed while averaging the pressure of the exhaust gas V supplied from the plurality of gas sampling pipes 6 by the plurality of needle shafts 7. The exhaust gas V is supplied to the analysis probe of the gas sampling device 1. The pressure of the exhaust gas V supplied from the gas sampling pipe 6 is monitored by a pressure gauge 75. The mixing tube 4 includes a blower tube 81 that blows gas (blower) discharged from the pump 82, a dust discharge port 83, and a dust discharge unit 84.

By the way, while the generator of the thermal power plant is operating, the temperature inside the exhaust gas passage 91 through which the exhaust gas V flows is kept at a high temperature of about 350 ° C. Since the gas sampling pipe 6 and the mixing pipe 4 are disposed inside the exhaust gas passage 91, the temperature is unlikely to decrease. In the interior of this reason, the mixing pipe 4, the ammonia reacts with sulfur oxides, etc., ammonium bisulfate, ammonium pyrosulfate _{((NH 4) 2 S 2} O 7), or ammonium aluminum sulfate _(ALNH 4 _(SO 4) ₂ ) It is difficult to become an ammonia compound such as. Since the exhaust gas V is sampled from the mixing tube 4 to the gas sampling device 1, an error for the ammonia compound is suppressed and the ammonia amount (concentration) can be sampled with high accuracy.

  As shown in FIG. 2, the analysis probe outer tube 3 is a hollow member in which one end is disposed inside the mixing tube 4 through which the exhaust gas V flows and the other end is disposed outside the mixing tube 4. The analysis probe outer tube 3 is, for example, hollow and cylindrical, and includes a flange 41 that protrudes radially from the outer peripheral surface. As shown in FIG. 2, the flange 41 seals a gap between the mixing tube 4 and the analysis probe outer tube 3.

  The analysis probe inner tube 2 passes through the analysis probe outer tube 3 so that one end is disposed inside the mixing tube 4 and the other end is disposed outside the mixing tube 4 (outside the exhaust gas flow channel 91). ing. As shown in FIG. 2, the analysis probe inner tube 2 has an opening 2 a that opens inside the mixing tube 4 and a hole 2 h provided in the outer wall of the analysis probe inner tube 2 inside the analysis probe outer tube 3. And comprising.

  One end of the transfer tube 23 is connected to the analysis probe inner tube 2, and the other end is immersed in the absorption liquid 131 stored in the absorption bottle 13. The connection pipe 24 connects the absorption bottle 13 and the suction pump 14. The end of the connection pipe 24 on the absorption bin 13 side is disposed in the internal space and is not immersed in the absorption liquid 131. The absorption bin 13 is sealed except for a portion through which the transport pipe 23 and the connection pipe 24 pass. For this reason, when the suction pump 14 is operated, the inside of the absorption bottle 13 and the inside of the analysis probe inner tube 2 become negative pressure, and the exhaust gas V is sucked from the opening 2 a of the analysis probe inner tube 2. In this way, the transport pipe 23 transports the exhaust gas V collected from the opening 2 a of the analysis probe inner pipe 2 to the absorption bin 13.

  The exhaust gas V conveyed to the absorption bin 13 passes through the absorption liquid 131 and is conveyed to the gas meter 15 through the connection pipe 25. The gas meter 15 measures the flow rate of the exhaust gas V sucked by the suction pump 14.

  The introduction tube 21 has one end connected to the analysis probe outer tube 3 and the other end connected to the cleaning liquid pump 11. The connection pipe 22 has one end connected to the cleaning liquid pump 11 and the other end immersed in the cleaning liquid 121 stored in the cleaning liquid bottle 12. The cleaning liquid 121 is pure water, for example.

  When the cleaning liquid pump 11 is operated, the cleaning liquid 121 is sucked up by the connection pipe 22, and the cleaning liquid 121 is introduced into the analysis probe outer pipe 3 through the introduction pipe 21. That is, the introduction tube 21 can introduce the cleaning liquid 121 into the analysis probe outer tube 3.

  When measuring the ammonia amount (concentration) contained in the exhaust gas V, the suction pump 14 is first operated. Thereby, since the exhaust gas V passes through the absorbent 131, ammonia contained in the exhaust gas V is absorbed by the absorbent 131.

  The exhaust gas V that has absorbed ammonia is discarded after its flow rate is measured by the gas meter 15. After the exhaust gas V having a predetermined flow rate is collected, the cleaning liquid pump 11 is operated while the suction pump 14 is operating. Accordingly, the cleaning liquid 121 is introduced into the analysis probe outer tube 3.

  The cleaning liquid 121 introduced into the analysis probe outer tube 3 is introduced into the analysis probe inner tube 2 through the hole 2h. Since the suction pump 14 is in operation, the cleaning liquid 121 introduced into the analysis probe inner tube 2 is sucked toward the absorption bottle 13.

  Ammonia adhering to the inner wall of the analysis probe inner tube 2 is absorbed by the cleaning liquid 121. Thereafter, the cleaning liquid 121 that has absorbed ammonia is conveyed to the absorption bottle 13. The absorption bottle 13 stores the cleaning liquid 121 that has absorbed ammonia together with the absorbing liquid 131.

  Then, the liquid stored in the absorption bottle 13 is conveyed to an analyzer (not shown), and the ammonia amount (concentration) is measured. The ammonia amount (concentration) is measured based on, for example, “Ammonia Analysis Method in Exhaust Gas” defined in JISK0099. The absorbing liquid 131 is a boric acid solution. Then, the ammonia amount (concentration) is measured by indophenol blue absorptiometry.

  As shown in FIG. 2, the gas sampling device 1 according to the present embodiment includes a thermometer 5, a control unit 30, and an auxiliary pipe 26. The thermometer 5 is connected to the control unit 30 and can transmit the temperature measurement result of the analysis probe inner tube 2 to the control unit 30.

  The control unit 30 is a computer such as a personal computer (PC), and includes an input interface, an output interface, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an internal storage. And a device. The input interface, output interface, CPU, ROM, RAM, and internal storage device are connected by an internal bus. The control unit 30 can change the output signal according to the change of the input signal. The measurement result of the thermometer 5 is stored in the internal storage device at regular intervals.

  The auxiliary tube 26 has one end connected to the introduction tube 21 and the other end connected to the analysis probe inner tube 2. The auxiliary pipe 26 includes the first valve 16 at an intermediate portion. The first valve 16 is connected to, for example, the control unit 30 and opens and closes according to an output signal from the control unit 30.

  Further, the transport pipe 23 includes a second valve 17 at an intermediate portion. The second valve 17 is connected to the control unit 30, for example, and opens and closes according to the output signal of the control unit 30. The control unit 30 is connected to the cleaning liquid pump 11 and the suction pump 14. The control unit 30 can operate or stop the cleaning liquid pump 11 and the suction pump 14.

  The gas sampling device 1 can introduce the cleaning liquid 121 into the analysis probe inner tube 2 through the introduction tube 21 and the analysis probe outer tube 3 before collecting the analysis exhaust gas. Since the inside of the exhaust gas passage 91 is at a high temperature of about 350 ° C., the analysis probe inner pipe 2 is also at a high temperature. Therefore, the cleaning liquid 121 introduced into the analysis probe inner tube 2 evaporates into a gas.

  When the cleaning liquid 121 is continuously introduced into the analysis probe inner tube 2, the analysis probe inner tube 2 is gradually cooled. When the temperature of the inner wall of the analysis probe inner pipe 2 becomes 100 ° C. or less, which is the boiling point of the cleaning liquid 121, the cleaning liquid 121 passes through the analysis probe inner pipe 2 in a liquid state. The ammonia compound that may adhere to the inner wall of the analysis probe inner tube 2 is dissolved in the cleaning liquid 121 in a liquid state and removed from the inner wall of the analysis probe inner tube 2.

  Since the gas sampling device 1 includes the thermometer 5, it can be confirmed that the cleaning liquid 121 passes in a liquid state on the inner wall of the analysis probe inner tube 2 located on the mixing tube 4 side of the hole 2h. Therefore, the gas sampling device 1 can easily remove the ammonia compound adhering to the inner wall of the analysis probe inner tube 2 located on the mixing tube 4 side with respect to the hole 2h. For this reason, the possibility that ammonia produced by the decomposition of the ammonia compound during the collection of the exhaust gas V is mixed with the exhaust gas V is reduced. Therefore, the gas sampling device 1 can shorten the time until the measurement result is stabilized.

  FIG. 3 is an explanatory diagram for explaining a flow rate adjusting mechanism for adjusting the pressure of the exhaust gas supplied from the gas sampling pipe. FIG. 3 is a schematic view schematically showing a plane passing through the central axis of the needle axis and perpendicular to the direction in which the mixing tube extends. As shown in FIG. 3, the mixing tube 4 is a hollow cylindrical member.

  The needle shaft 7 includes a shaft main body, a valve body 71 having a tapered surface in which the front end of the shaft main body is processed into a taper shape, and an axial direction (center) of the shaft main body from the valve body 71 (front end) to the rear end 73. A through hole 72 penetrating in a direction parallel to the axis) and a position adjusting portion 74 disposed in the vicinity of the flow path wall 90. The material of the needle shaft 7 is, for example, ceramic or titanium. The needle shaft 7 made of ceramic or titanium has high wear resistance.

  The position adjusting unit 74 is a male screw fastened to the fixing unit 90N of the flow path wall 90. For this reason, by rotating the needle shaft 7 around the central axis, the position can be adjusted back and forth in the axial direction of the needle shaft 7 (direction parallel to the central axis). In this way, the pressure of the exhaust gas V flowing from the gas sampling pipe 6 from the outside of the exhaust gas flow channel 91 (outside the flue) can be adjusted, so that even if there is a change over time due to accumulation of dust such as soot dust, The flow rate of the collection tube 6 can be easily adjusted.

  The pressure gauge 75 can measure the exhaust gas pressure in the through hole 72. The flow path connecting the pressure gauge 75 and the through hole 72 is a sealed flow path.

  At the time of cleaning, a pump (not shown) is connected to the rear end 73 side of the through hole 72 so that air can be blown into the through hole 72. Thereby, the dust accumulated in the through-hole 72 and the gas sampling pipe 6 is removed.

  The valve body 71 is opposed to the opening 61 </ b> B opened at the end 61 </ b> C of the gas sampling pipe 6 inserted into the mixing pipe 4. A gap between the valve body 71 and the end 61 </ b> C of the gas sampling pipe 6 is an orifice 63. For this reason, when the position of the needle shaft 7 is adjusted back and forth in the axial direction (direction parallel to the central axis) from the outside of the flue, the amount of exhaust gas flowing through the orifice 63 and flowing into the internal space of the mixing tube 4 Changes. This change in the amount of exhaust gas can be measured with a pressure gauge 75.

  As described above, the flow rate adjusting mechanism according to the present embodiment includes a plurality of needle shafts 7 each having a shaft body in which the valve body 71 at the tip is inserted into the mixing tube 4. An orifice 63 is formed between each valve element 71 and the opening 6B of the gas sampling pipe 6 facing each other. The flow rate adjustment mechanism according to the present embodiment exemplifies a flow rate adjustment valve in which the valve body 71 is called a tapered (conical) needle valve. The flow rate adjusting mechanism is not limited to this, and the valve body 71 may be spherical or mushroom type.

  The gas sampling device 1 can adjust the flow rate of the exhaust gas V for each gas sampling tube 6 according to the position of the valve body 71 inside the mixing tube 4. For this reason, it is not necessary to adjust the flow rate outside the exhaust gas passage 91 having a low temperature, and the compounds generated by the temperature decrease are suppressed. As a result, the analysis exhaust gas 42 in the mixing pipe 4 has a small error in the ammonia amount (concentration) to be measured.

  When the positions of all the needle shafts 7 shown in FIG. 1 between the gas sampling pipes 6 are adjusted, the pressure of the exhaust gas V supplied from each gas sampling pipe 6 is adjusted. When the pressure of the exhaust gas V supplied from each gas sampling tube 6 approaches a predetermined value, the flow rate of the exhaust gas V supplied from each gas sampling tube 6 approaches a constant value. As a result, the ammonia amount (concentration) contained in the exhaust gas 42 for analysis in the mixing tube 4 approaches the average of the ammonia amount (concentration) contained in the exhaust gas 62 inside each gas sampling tube 6.

  As described above, the analysis exhaust gas 42 inside the mixing tube 4 is absorbed by the liquid stored in the absorption bottle 13 in FIG. The liquid in which the exhaust gas 42 for analysis is absorbed (the liquid stored in the absorption bottle 13) is analyzed, and the ammonia amount (concentration) is measured. For this reason, the measurement accuracy of the ammonia amount (concentration) is high. And the installation man-hour of the analysis probe itself or the analysis probe and the analyzer is suppressed.

  Dust such as soot 95 tends to accumulate inside the mixing tube 4. For this reason, as shown in FIG. 1, a blowing pipe 81 is connected to the mixing pipe 4. The blower pipe 81 is connected to a pump 82 provided outside the exhaust gas passage 91.

  4 and 5 are schematic views showing the inside of the mixing tube during cleaning. The cross section of FIG. 4 shows the vicinity of the blower tube 81, and the cross section of FIG. 5 shows the vicinity of the dust discharge port 83 and the dust discharge unit 84. As shown in FIG. 4, high-pressure air is injected into the mixing tube 4 by the blower tube 81. Thereby, a swirl flow along the inner wall of the mixing tube 4 is generated. As shown in FIG. 5, the high-pressure air injected into the mixing tube 4 is outside the mixing tube 4 through the dust discharge port 83 and the dust discharge unit 84 while attracting the gas in the mixing tube 4. It is discharged into the exhaust gas passage 91. As a result, clogging of the mixing tube 4 due to dust such as dust 95 is suppressed. The dust discharge port 83 may be provided with a gate valve or the like. If there is a gate valve, the airtightness inside the mixing tube 4 at the time of measurement increases, and the ammonia amount (concentration) distribution inside the mixing tube 4 comes closer to uniform.

  As described above, in the gas sampling device 1 according to the present embodiment, the gas sampling pipe 6 and the mixing pipe 4 are arranged in the exhaust gas flow channel 91 (flue). The gas sampling pipe 1 introduces exhaust gas flowing through the exhaust gas passage 91. The mixing pipe 4 mixes the exhaust gas V (exhaust gas 62 in each gas sampling pipe 6) flowing in from the plurality of gas sampling pipes 6 as the exhaust gas 42 for analysis. The gas sampling device 1 includes a flow rate adjusting mechanism that adjusts the pressure of the exhaust gas V flowing from the gas sampling tube 6 in the mixing tube 4. As a result, in the exhaust gas 42 for analysis, the variation in the ammonia gas component contained in the exhaust gas V in the exhaust gas flow path 91 is alleviated, and the analysis exhaust gas 42 is taken in via the analysis probe and analyzed.

(Modification)
A modification of this embodiment will be described with reference to FIGS. 6, 7, and 8. FIG. 6 is a schematic diagram showing a gas sampling device according to a modification of the present embodiment. FIG. 7 is a schematic diagram of a VII-VII ′ section in FIG. 6. FIG. 8 is a schematic diagram of a VIII-VIII ′ cross section in FIG. 6. In addition, the same code | symbol is attached | subjected to the same component as what was mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 6, the cross section which cut | disconnected the exhaust gas flow path 91 with the plane orthogonal to the flow direction G of the exhaust gas V is a rectangle, for example. The gas sampling device 1 </ b> A is disposed at a corner portion of the exhaust gas flow channel 91 and is fixed to the flow channel wall 90.

  As shown in FIGS. 6 and 7, the gas sampling device 1 </ b> A includes a mixing tube 4, a light emitting unit 111, and a light receiving unit 112. The light emitting unit 111 and the light receiving unit 112 are disposed outside the flow path wall 90, and the mixing tube 4 penetrates the flow path wall 90.

  As shown in FIG. 7, the inner tube 113 is inserted into one end of the mixing tube 4, and the inner tube 114 is inserted into the other end of the mixing tube 4. The inner tube 113 and the inner tube 114 are cylindrical members. End portions of the inner tube 113 and the inner tube 114 located in the mixing tube 4 are closed with a transparent member such as glass. The light emitting unit 111 is provided at the end of the inner tube 113 protruding from the mixing tube 4, and the light receiving unit 112 is provided at the end of the inner tube 114 protruding from the mixing tube 4.

  As shown in FIG. 7, a blower pipe 81 and a blower pipe 81 are connected to the mixing pipe 4. As shown in FIG. 6, the blower pipe 81 is connected to a pump 82 provided outside the exhaust gas passage 91, and the blower pipe 81 is connected to a pump 82 provided outside the exhaust gas passage 91. . Thereby, the blower pipe 81 and the blower pipe 81 can introduce high-pressure air into the mixing pipe 4. As shown in FIG. 7, the portion of the blower tube 81 that is inserted into the mixing tube 4 is parallel to the dust discharge port 83 and is disposed on the same circumference as the dust discharge port 83.

  The light emitting unit 111 includes a light emitting unit 111 </ b> A that emits a laser toward the light receiving unit 112. The light emitting unit 111A is, for example, a semiconductor laser, and emits light in the infrared or near infrared wavelength region as measurement light. The light receiving unit 112 includes a light receiving unit 112A that receives the laser emitted from the light emitting unit 111A. The light receiving unit 112A is, for example, a photodiode. The laser emitted from the light emitting unit 111A passes through the optical path L parallel to the axial direction of the mixing tube 4 and enters the light receiving unit 112A. Since the analysis exhaust gas 42 is introduced into the mixing tube 4, the laser passes through the analysis exhaust gas 42. Molecules such as ammonia contained in the exhaust gas 42 for analysis have an absorption spectrum of light unique to each molecule. The amount of light absorption (absorbance) at a specific wavelength of the laser varies according to the amount of ammonia (concentration) contained in the exhaust gas 42 for analysis.

  As shown in FIG. 6, the light receiving unit 112 is connected to the control unit 30, and the light receiving unit 112 </ b> A converts the detection value into an electric signal and transmits the electric signal to the control unit 30. In the control unit 30, the CPU calculates the ammonia amount (concentration) contained in the exhaust gas 42 for analysis from the detected value of the light receiving unit 112 </ b> A in cooperation with the memory, and stores the calculated value in the storage unit. More specifically, the control unit 30 obtains the concentration of ammonia contained in the exhaust gas V by calculating the light absorption amount (absorbance) at a specific wavelength of the laser from the detection value of the light receiving unit 112A.

  The pumps 82, 82 are connected to the control unit 30 and operate according to instructions from the control unit 30. When the pumps 82 and 82 are operated at the time of cleaning, high-pressure air is injected into the mixing tube 4 by the blower tubes 81 and 81. The high-pressure air injected into the mixing tube 4 is discharged to the outside of the mixing tube 4 through the dust discharge ports 83 and 83 while attracting the gas in the mixing tube 4. Thereby, a swirl flow along the inner wall of the mixing tube 4 is generated. Dust such as the dust 95 is pressed against the inner wall of the mixing tube 4 in a swirling flow and discharged from the dust discharge ports 83 and 83. For this reason, the amount of dust is reduced in the region through which the optical path L passes. As a result, the gas sampling device 1 can improve the accuracy of gas analysis.

  As shown in FIG. 7, the optical path L is disposed in the mixing tube 4 at a position where the needle shaft 7 and the gas sampling tube 6 are not irradiated. In consideration of gravity and the like, it is more preferable that the optical path L passes above the needle shaft 7 and the gas sampling pipe 6 in the vertical direction. With this structure, the influence of dust such as dust 95 on the optical path L is reduced.

  As described above, the gas sampling device 1A according to the modification of the present embodiment includes the light emitting unit 111A that emits the measurement light, and the light receiving unit 112A that receives the measurement light that has passed through the analysis exhaust gas 42. . Thus, the amount (concentration) of ammonia (gas component) to be measured with respect to the exhaust gas 42 for analysis is measured without collecting a part of the exhaust gas outside the exhaust gas passage 91. For this reason, the measurement accuracy of the ammonia amount (concentration) is high. And the installation man-hour of the analysis probe itself or the analysis probe and the analyzer is suppressed.

1, 1A Gas sampling device 2 Analysis probe inner tube 2a Opening 2h Hole 3 Analysis probe outer tube 4 Mixing tube 5 Thermometer 6 Gas sampling tube 7 Needle shaft 11 Cleaning liquid pump 12 Cleaning liquid bottle 13 Absorption bottle 14 Suction pump 15 Gas meter 16, 17 Valve 21 Introducing tube 22 Connecting tube 23 Conveying tube 24 Connecting tube 25 Connecting tube 26 Auxiliary tube 30 Control unit 41 Flange 42 Exhaust gas for analysis (internal space)
61A, 61B Opening 61R Curved portion 62 Exhaust gas 63 inside gas sampling tube Orifice 71 Valve body 72 Through hole 73 Rear end 74 Position adjustment unit 75 Pressure gauge 81 Blow pipe 82 Pump 83 Dust discharge port 84 Dust discharge unit 90N Fixing unit 90 Flow Road wall 91 Exhaust gas channel 92 Denitration device 95 Dust 111 Light emitting unit 111A Light emitting unit 112 Light receiving unit 112A Light receiving unit 113 Inner tube 114 Inner tube 121 Cleaning liquid 131 Absorbing liquid L Optical path V Exhaust gas

Claims (5)

A plurality of gas sampling pipes arranged in the exhaust gas flow channel for introducing exhaust gas flowing through the exhaust gas flow channel;
A mixing tube that is disposed in the exhaust gas flow path and mixes the exhaust gas flowing in from the plurality of gas sampling tubes as exhaust gas for analysis inside;
A flow rate adjusting mechanism for adjusting the pressure of the exhaust gas flowing from the gas sampling pipe in the mixing pipe ;
The flow rate adjusting mechanism includes a shaft in which a valve body at a tip is inserted into the mixing pipe, and the valve body forms an orifice between the opening of the gas sampling pipe . The shaft is provided with a through hole extending through the inner, centered parallel to the axis direction, the gas sampling device according to claim 1. The flow rate adjustment mechanism is gas sampling device according to claim 1 or 2 from the outside of the exhaust gas flow channel can adjust the pressure of the exhaust gas flowing from the gas sampling tube. The gas sampling device according to any one of claims 1 to 3 , wherein the liquid in which the exhaust gas for analysis is absorbed is analyzed. A light emitting unit that emits light for measurement, and a light receiving portion for receiving the light for measurement which has passed through the exhaust gas for the analysis, gas sampling device according to any one of claims 1 3 .

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