JP5989699B2 - Laser gas analyzer and gas sampling unit - Google Patents

Description

  The present invention relates to a laser gas analyzer and a gas sampling unit.

  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 passage on the outlet side of the denitration apparatus, and the ammonia amount (concentration) contained therein is accurately measured. There is a need. Therefore, as in the techniques of Patent Document 1 and Patent Document 2, an exhaust gas sampling pipe is provided in the exhaust gas flow path, and a part of the exhaust gas is sampled outside the exhaust gas flow path through the exhaust gas sampling pipe.

JP 2012-093156 A JP 2010-236877 A

  The exhaust gas passage contains dust such as remaining dust, and it is necessary to collect dust such as dust in order to accurately measure the concentration of ammonia as the target gas by laser gas analysis. When there is a lot of dust such as soot dust, the accuracy of the target gas analysis may be reduced in the laser gas analysis. As a method of collecting dust such as soot dust, there is an electric dust collector described in Patent Document 2, but a power source is required, and if it is attempted to reduce the amount of dust within the sampling range, the gas to be analyzed more easily It is desired to collect dust.

  The present invention has been made in view of the above, and includes a laser gas analyzer with high accuracy of gas analysis that suppresses the influence of dust by gravity settling and a gas sampling unit that can suppress the influence of dust by gravity settling. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, a laser gas analyzer of the present invention includes a cylindrical first cylindrical portion, a cylindrical second cylindrical portion, one end of the first cylindrical portion, A gas sampling unit comprising: a flexible bent portion connected to one end of the second tube portion and bent so that the other end of the second tube portion is vertically downward; and the first tube A light-emitting unit that emits measurement light along a direction in which the unit extends, and a light-receiving unit that receives the measurement light that has passed through the internal space of the first tube unit.

  Even if the gas sampling unit receives wind pressure, the bent portion has flexibility, so that the direction of the second tube portion can be flexibly along the flow direction of the exhaust gas. For this reason, the inside of a 2nd cylinder part will be in the state suitable for sedimentation of dusts, such as a dust. Dust contained in the exhaust gas is reduced by sedimentation due to its own weight, and the amount of dust is reduced in a region through which measurement light passes. Thereby, the amount of dust is reduced in the region through which the measurement light passes. As a result, the laser type gas analyzer has high gas analysis accuracy.

  In order to solve the above-described problems and achieve the object, as another aspect of the present invention, a gas sampling unit includes a cylindrical first cylindrical portion, a cylindrical second cylindrical portion, and the first cylindrical portion. A flexible bent portion that connects one end of the second cylindrical portion and one end of the second cylindrical portion, and bends so that the other end of the second cylindrical portion is directed downward in the vertical direction. It is inserted inside.

  Even if the gas sampling unit receives wind pressure, the bent portion has flexibility, so that the direction of the second tube portion m can be flexibly aligned with the flow direction of the exhaust gas. For this reason, the inside of a 2nd cylinder part will be in the state suitable for sedimentation of dusts, such as a dust. Dust contained in the exhaust gas is reduced by sedimentation due to its own weight, and the amount of dust is reduced in a region through which measurement light passes.

  As a desirable mode of the present invention, it is preferable that a fin wound spirally is provided on the outer periphery of the second cylindrical portion. With this structure, even if the gas sampling unit receives wind pressure, the possibility of causing the rotational movement of the second cylindrical portion is reduced. As a result, dust such as dust is further reduced from the region through which the optical path passes. As a result, the laser type gas analyzer has high gas analysis accuracy.

  As a desirable mode of the present invention, it is preferable that a rectifying unit having a vertical rectifying action is provided inside the second cylindrical portion. With this structure, the inside of the second cylindrical portion is in a state suitable for sedimentation of dust such as dust, and the amount of dust is reduced.

  As a desirable mode of the present invention, it is preferable that the first tube portion is provided with a gas discharge mechanism for discharging the gas in the internal space. As a result, the exhaust gas enters the inside of the second cylindrical portion, and the exhaust gas flow is circulated.

  ADVANTAGE OF THE INVENTION According to this invention, the gas sampling unit which can suppress the influence of dust by gravity sedimentation and can suppress the influence of dust by gravity sedimentation and the laser-type gas analyzer with high precision of gas analysis can be provided.

FIG. 1 is a top view schematically illustrating the laser gas analyzer according to the present embodiment. FIG. 2 is a cross-sectional view of the laser gas analyzer according to the present embodiment. FIG. 3 is an explanatory diagram for explaining a side surface of the second cylindrical portion of the laser gas analyzer according to the present embodiment. FIG. 4 is a top view of the second cylindrical portion of the laser gas analyzer according to the present embodiment as viewed from the top in the vertical direction. FIG. 5 is an explanatory diagram for explaining a gas discharge mechanism of the laser gas analyzer according to the present embodiment.

  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.

  FIG. 1 is a top view schematically illustrating the laser gas analyzer according to the present embodiment. FIG. 2 is a cross-sectional view of the laser gas analyzer according to the present embodiment. FIG. 3 is an explanatory diagram for explaining a side surface of the second cylindrical portion of the laser gas analyzer according to the present embodiment. FIG. 4 is a top view of the second cylindrical portion of the laser gas analyzer according to the present embodiment as viewed from the top in the vertical direction. FIG. 5 is an explanatory diagram for explaining a gas discharge mechanism of the laser gas analyzer according to the present embodiment. In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ orthogonal coordinate system. A direction in which an optical path to be described later travels is referred to as an X-axis direction, a direction orthogonal to the X-axis direction is referred to as a Y-axis direction, and a direction orthogonal to each of the X-axis direction and the Y-axis direction is referred to as a Z-axis direction. The Z-axis direction is the vertical direction. The X axis is orthogonal to the YZ plane. The Y axis is orthogonal to the XZ plane. The Z axis is orthogonal to the XY plane. The XY plane includes an X axis and a Y axis. The XZ plane includes an X axis and a Z axis. The YZ plane includes a Y axis and a Z axis. In the present embodiment, it is assumed that the exhaust gas in the exhaust gas flow path to be described later circulates along the Z-axis direction. The cross section of FIG. 5 is a cross section of the YZ plane orthogonal to the AA cross section of FIG.

  The laser gas analyzer 100 according to the present embodiment includes a transmission / reception unit 10, a gas sampling unit 30, a mirror unit 20, and a control device 40.

  The laser type gas analyzer 100 of this embodiment is attached to an exhaust gas flow channel 91 surrounded by a flow channel wall 90. The exhaust gas passage 91 is an exhaust gas passage on the outlet side of the denitration apparatus, and it is necessary to accurately measure the amount (concentration) of ammonia contained in the exhaust gas V isolated from the atmosphere CA.

  In the laser type gas analyzer 100 of the present embodiment, the gas sampling unit 30 on the mirror unit 20 side is inserted through the flow path wall 90 and inserted into the exhaust gas flow path 91 in the X-axis direction shown in FIG. As shown in FIG. 1, the gas sampling unit 30 includes a first cylinder part 31, a rectifying plate 32, a second cylinder part 51, and a bent part 52.

  The control device 40 includes a CPU (: Central Processing Unit) 41, a ROM (: Read Only Memory), a memory (RAM) such as a RAM (: Random Access Memory), and a storage unit 43 such as a flash memory and a hard disk drive.

  The transmission / reception unit 10 includes a light emitting unit 11, a light receiving unit 12, a signal processing circuit 13, and an optical member 14. The mirror unit 20 includes a mirror 21 and an optical member 22. The optical member 14 and the optical member 22 set the focal point of the optical system with a lens or the like, and include an air shutter or the like. In the light emitting unit 11, the laser diode generates laser light having a wavelength that matches the absorption wavelength peculiar to ammonia of the measurement target gas, reflects it to the mirror 21 included in the mirror unit 20, and causes the light receiving unit 12 to receive the light. The light receiving unit 12 is, for example, a photodiode. The measurement light in this embodiment is light in the infrared wavelength region.

  As shown in FIG. 2, the control device 40 is connected to the signal processing circuit 13 via an input / output interface. The signal processing circuit 13 is connected to the light emitting unit 11 and the light receiving unit 12, converts the laser light emission of the light emitting unit 11 and the detection value of the light receiving unit 12 into an electrical signal, and sends it to the control device 40. The laser light is irradiated in parallel to the X-axis direction, and the forward optical path LT and the backward optical path LR are parallel. In the present embodiment, the mirror 21 is used, but the light emitting unit 11 and the light receiving unit 12 are arranged at positions facing each other via the first tube unit 31, and the light receiving unit 12 emits light from the light emitting unit 11. The laser beam that has passed through the internal space of the cylindrical portion 31 may be received. In the control device 40, the CPU 41 cooperates with the memory 42 to calculate the concentration (for example, ammonia amount) of the target gas from the detection value of the light receiving unit 12, and stores the calculated value in the storage unit 43.

  As shown in FIGS. 2 and 5, the first cylindrical portion 31 is a cylindrical shape whose longitudinal direction extends in the X-axis direction, and is an annular cylindrical member in the YZ plane. The first cylinder portion 31 includes a gas discharge mechanism EJ that discharges the exhaust gas V in the internal space to the exhaust gas passage 91. The forward optical path LT and the backward optical path LR, which are laser optical paths, pass through the hollow space of the first cylindrical portion 31.

  The mirror unit 20 is disposed in the hollow space of the first cylindrical portion 31. The wall surface of the mirror unit 20 has a structure that allows gas such as a mesh to pass through, and does not hinder the airflow.

  The bent portion 52 is a flexible hollow tube. The material of the bent portion 52 is, for example, a fluororesin, and the material itself has flexibility. The bent portion 52 may be a metal, or may be flexible by processing into a bellows shape.

  As shown in FIGS. 2, 3, and 4, the second cylindrical portion 51 is a cylindrical shape whose longitudinal direction extends in the vertical direction (Z-axis direction) and is an annular cylindrical member in the XY plane. . The hollow space of the second cylindrical portion 51 communicates with the hollow space of the first cylindrical portion 31 through the hollow space of the bent portion 52. The 1st cylinder part 31, the bending part 52, and the 2nd cylinder part 51 are united, and become an L-shaped pipe.

As shown in FIG. 3, the outer periphery of the 2nd cylinder part 51 is equipped with the fin 54 wound helically. In the present embodiment, the fin 54 is provided with the first fin 54A, the second fin 54B, and the third fin 54C having different positions in the vertical direction. The shape of the fin 54 may be one fin, two fins, or four or more fins.

  As shown in FIGS. 2 and 4, the second cylinder portion 51 includes a rectifying portion 53 having a vertical rectifying action. In the present embodiment, the rectifying unit 53 is a plate-like rectifying plate, but may be a lattice.

  As shown in FIGS. 1 and 5, the rectifying plate 32 is fixed at a position adjacent to the first cylindrical portion 31. When the flow direction of the exhaust gas is G, the exhaust gas flows in the Z direction. The distance between the first cylinder part 31 on the upstream side of the exhaust gas passage 91 and the rectifying plate 32 is larger than the distance between the first cylinder part 31 on the downstream side of the exhaust gas passage 91 and the rectifying plate 32. With this structure, an introduction path 32 i is formed between the first cylinder portion 31 on the upstream side of the exhaust gas passage 91, and the discharge is performed between the first cylinder portion 31 on the downstream side of the exhaust gas passage 91 and the rectifying plate 32. A path 32e is formed.

  The cross-sectional area of the introduction path 32i in the XY plane is larger than the cross-sectional area of the discharge path 32e in the XY plane. With this structure, the exhaust gas flow G1 entering from the introduction path 32i increases in flow rate as it approaches the discharge path 32e, and is discharged as the exhaust gas flow G2.

  As shown in FIG. 5, the gas discharge mechanism EJ shown in FIG. 2 has a gas discharge hole 34 formed in the wall surface of the first cylindrical portion 31. The wall surface end 34f1 and the wall surface end 34f2 in the circumferential direction of the first cylinder portion 31 of the gas discharge mechanism EJ face the gas discharge hole 34 shown in FIG. The range of the angle θ formed by the wall surface end 34f1 in the circumferential direction of the first tube portion 31, the center Xr of the first tube portion 31, and the wall surface end portion 34f2 is partially or entirely viewed from the outside. It is not covered with and exposed. As described above, at least one of the wall surface end portion 34f1 or the wall surface end portion 34f2 faces the rectifying plate 32.

  As shown in FIG. 5, the exhaust gas flow G1 entering from the introduction path 32i is discharged as the exhaust gas flow G2 from the discharge path 32e. The exhaust gas flow G2 discharged from the discharge path 32e passes around the gas discharge hole 34, and causes the exhaust gas flow e4 involved in the exhaust gas G2. The exhaust gas flow e4 lowers the pressure around the gas discharge hole 34, and sucks the hollow space of the first cylindrical portion 31 by a negative pressure to cause a swirling flow of the exhaust gas flow e3, the exhaust gas flow e2, and the exhaust gas flow e1. The exhaust gas flow e1 becomes a spiral swirl flow, and the exhaust gas swirls for a long time in the hollow space of the first cylindrical portion 31. As described above, the gas discharge mechanism EJ is non-powered and can cause the flow of the air flow in the first cylindrical portion 31.

  As shown in FIG. 2, the exhaust gas flow e1 shown in FIG. 5 causes an exhaust gas flow g1, an exhaust gas flow g2, an exhaust gas flow g3, and an exhaust gas flow g4. The other end of the second cylindrical portion 51 is on the side opposite to one end connected to the bent portion 52, and the opening is directed downward in the vertical direction. While the exhaust gas flow g1 entering from the opening of the second cylinder part 51 passes through the second cylinder part 51, dust such as soot settles down due to gravity, and the amount of dust reaching the first cylinder part 31 is reduced.

  As described above, the laser gas analyzer 100 according to the present embodiment includes the gas sampling unit 30. The gas sampling unit 30 includes a first tube portion 31, a second tube portion 51, and a bent portion 52 that connects one end of the first tube portion 31 and one end of the second tube portion 51. The longitudinal direction of the first cylinder part 31 is different from the longitudinal direction of the second cylinder part 51. With this structure, the other end of the second cylinder portion 51 is disposed downward in the vertical direction. And the bending part 52 has flexibility. Inside the exhaust gas passage 91, the gas sampling unit 30 receives wind pressure by the air flow of the exhaust gas V. Since the bent part 52 has flexibility in the gas sampling unit 30, the longitudinal direction of the second cylinder part 51 can be flexibly along the flow direction G of the exhaust gas. For this reason, the inside of the 2nd cylinder part 51 will be in the state suitable for sedimentation of dust, such as dust. And in the area | region where the outward path optical path LT in the 1st cylinder part 31 and the return path optical path LR pass, dust amount reduces. As a result, the laser type gas analyzer 100 of the present embodiment increases the accuracy of gas analysis.

  A fin 54 wound spirally is provided on the outer periphery of the second cylindrical portion 51. With this structure, the gas sampling unit 30 receives wind pressure and reduces the possibility that the second cylindrical portion 51 causes a rotational motion in the YZ plane. For this reason, the other end of the second cylindrical portion 51 is easily oriented in the vertical direction. And the inside of the 2nd cylinder part 51 will be in the state suitable for sedimentation of dust, such as dust. And in the area | region where the outward path optical path LT in the 1st cylinder part 31 and the return path optical path LR pass, dust amount reduces. As a result, the laser type gas analyzer 100 of the present embodiment increases the accuracy of gas analysis.

  A rectifying unit 53 having a rectifying action in the vertical direction is provided inside the second cylinder unit 51. For this reason, the inside of the 2nd cylinder part 51 will be in the state suitable for sedimentation of dust, such as dust. And in the area | region where the outward path optical path LT in the 1st cylinder part 31 and the return path optical path LR pass, dust amount reduces. As a result, the laser type gas analyzer 100 of the present embodiment increases the accuracy of gas analysis.

  The first cylinder portion 51 includes a gas discharge mechanism EJ that discharges the gas in the hollow space. With this structure, a part of the exhaust gas enters the second cylindrical portion 51 that communicates with the inside, and the exhaust gas flow is circulated. As a result, the laser type gas analyzer 100 of this embodiment can always analyze the gas flowing through the exhaust gas passage 91. The exhaust gas in the internal space is discharged from the gas discharge hole 34 opened in the gas discharge mechanism EJ. As a result, the swirl flow becomes a spiral, and dust such as dust is further reduced from the forward path optical path LT and the return path optical path LR. The gas discharge mechanism EJ of the present embodiment can make the discharge from the gas discharge hole 34 smooth using the energy of the exhaust gas flow. For this reason, the laser-type gas analyzer 100 of this embodiment can perform gas analysis without power and in a state where dust such as dust is reduced. The gas discharge mechanism EJ may be, for example, a simple opening or a fan.

  As described above, the gas sampling unit 30 according to the present embodiment has been described as applied to the laser gas analyzer, but may be applied as a sampler to other gas analyzers.

DESCRIPTION OF SYMBOLS 10 Transmission / reception unit 11 Light emission part 12 Light reception part 13 Signal processing circuit 14 Optical member 20 Mirror unit 21 Mirror 22 Optical member 30 Gas sampling unit 31 1st cylinder part 32 Current plate 32i Introduction path 32e Release path 34 Gas discharge hole 40 Control apparatus 41 CPU
42 Memory 43 Storage part 51 Second cylinder part 52 Bending part 53 Rectifying part 54 Fin 90 Channel wall 91 Exhaust gas channel 100 Laser gas analyzer EJ Gas exhaust mechanism LR Return optical path LT Outbound optical path V Exhaust gas Xr Center

Claims (6)

A cylindrical first cylinder part, a cylindrical second cylinder part, one end of the first cylinder part and one end of the second cylinder part are connected, and the other end of the second cylinder part faces downward in the vertical direction. A gas sampling unit comprising a flexible bent portion that bends to become
A light emitting unit that emits light for measurement along a direction in which the first tube portion extends;
See containing and a light receiving portion for receiving the light for measurement that has passed through the inner space of the first cylindrical portion,
A laser-type gas analyzer comprising a fin wound in a spiral shape on the outer periphery of the second cylindrical portion . 2. The laser gas analyzer according to claim 1, wherein a rectifying unit having a rectifying action in a vertical direction is provided inside the second cylindrical unit. 3. The laser gas analyzer according to claim 1, wherein the first cylinder portion includes a gas discharge mechanism that discharges the gas in the internal space. A tubular first tube portion;
A cylindrical second tube portion having fins wound spirally on the outer periphery ,
A flexible bent portion that connects one end of the first tube portion and one end of the second tube portion and bends so that the other end of the second tube portion is vertically downward. ,
A gas sampling unit which is inserted into an exhaust gas flow path. 5. The gas sampling unit according to claim 4 , further comprising a rectifying unit having a rectifying action in a vertical direction inside the second cylindrical part. 6. The gas sampling unit according to claim 4, wherein the first tube portion includes a gas discharge mechanism that discharges the gas in the internal space.

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