JP2016067985A - Exhaust gas mixing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas mixing apparatus capable of facilitating manufacture and assembly and equalizing an exhaust gas velocity in the flow passage cross-section of an exhaust gas duct at a small duct length without increasing the power of an exhaust gas induction fan using the swirl flow of gas.SOLUTION: A gas mixer 1 that constitutes an exhaust gas mixing apparatus of the present invention is formed so that a plurality of triangular vanes 3 is disposed in a rectangular parallelepiped space 2, and the triangular vanes 3 are disposed so that one vertex 01 of each of the triangular vanes 3 corresponding to one another is disposed at a set point prescribed in the rectangular parallelepiped space, bases 7 facing the vertex 01 thereof are disposed on an outer surface 5 of the rectangular parallelepiped space in parallel to a gas inflow direction, and blade surfaces are inclined at the same angle with respect to an axis 8 in the gas inflow direction which pass through the set point and rotate about the axis 8 at equiangular pitches.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust gas mixing device, and more particularly to an exhaust gas mixing device provided on the upstream side of a denitration device that reduces nitrogen oxides in exhaust gas discharged from a combustion facility.

  In a power plant or the like, a denitration device for treating nitrogen oxides in exhaust gas generated from combustion facilities is used. The combustion facility is a combustion facility such as a gas turbine in addition to boilers such as coal burning, gas burning, and oil burning. The denitration apparatus adds a reducing agent such as ammonia and an ammonia compound to the exhaust gas on the upstream side, reacts the reducing agent and nitrogen oxide on the denitration catalyst provided in the denitration apparatus, and reduces the nitrogen. The reducing agent is basically supplied as a gas or the solution is directly sprayed into the exhaust gas. However, in the case of solution spraying, it is heated and vaporized by the high-temperature exhaust gas, so that it is eventually added in a gaseous state.

By the way, the amount of exhaust gas to be denitrated is, for example, 1000 MW class of power generation equipment, reaching ³ million m ³ N / h, and the reducing agent is 9000 m ³ N / h including dilution air. Thus, since the amount of exhaust gas is about 300 times that of the reducing agent gas, it is necessary to uniformly disperse a very small amount of reducing agent gas in a large amount of exhaust gas in order to increase the denitration efficiency.

In particular, the emission regulation value of nitrogen oxides (NOx) outside the system tends to be strengthened. For example, the denitration rate is 90% or more, and the slip ammonia concentration at which unreacted ammonia as a reducing agent flows out from the denitration apparatus is regulated to several ppm or less. In order to satisfy such regulations, it is important to control the molar ratio of ammonia (NH ₃ ) to nitrogen oxide (NOx) not to exceed 1 upstream of the denitration catalyst. For example, in Patent Document 1, the cross-section of the exhaust gas duct is divided into a plurality of regions, and a plurality of ammonia injection nozzles are arranged for each region, so that the ammonia injection amount can be controlled independently for each region. It has been proposed to As a result, it is possible to actually measure the NOx concentration or slip ammonia concentration in the cross section of the exhaust gas duct on the catalyst outlet side, and to finely adjust the ammonia injection amount for each region by feedback control.

However, even with the method of Patent Document 1, the exhaust gas flow velocity and the NOx concentration in each part of the cross section of the exhaust gas duct vary depending on the laying shape of the exhaust gas duct, the presence or absence of guide vanes, and the exhaust gas duct size. Further, even if the ammonia injection amount in a certain region is increased or decreased, the ammonia concentration in the portion on the extension does not necessarily increase or decrease. Therefore, the ammonia (NH ₃ ) injection amount corresponding to the variation in the exhaust gas flow rate and the NOx concentration. It is not easy to adjust.

That is, in order to satisfy the NOx outlet concentration and to prevent excess NH _{3 from} being discharged, NH ₃ / NOx at a very high rate in the entire region of the exhaust gas cross section on the inlet side of the denitration catalyst. The molar ratio must be uniform. Further, if the power generation load changes, the gas flow rate and the NOx concentration also fluctuate. Therefore, it is necessary to determine the adjustment conditions in consideration of each situation.

Therefore, for example, a general gas mixer described in Patent Documents 2 to 4 is provided in the exhaust gas flow path between the ammonia injection nozzle and the denitration catalyst, and the exhaust gas flow rate or NOx concentration is made uniform, and further, NH ₃ / It is conceivable to make the molar ratio of NOx uniform.

  For example, the gas mixer described in Patent Document 2 has a plurality of fixed swirl blades extending radially from the center in a rectangular tube, and mixes the gases by swirling gas passing through slits between the fixed swirl blades. I am doing so. Thereby, the load in the gas flow path cross section of the exhaust gas treatment reactor on the downstream side can be made uniform. In particular, there has been proposed a gas mixing apparatus in which a plurality of gas mixers are arranged in multiple stages and in a plurality of rows on the cross section of the exhaust gas flow path.

  On the other hand, the gas mixer described in Patent Document 2 is provided with the apex of a quadrangular pyramid-shaped fluid dividing member facing the gas inflow direction inside the rectangular tube, and the gas jetting hole is provided in the conical wall surface of the fluid dividing member. In this configuration, a short pipe is installed on the outlet side of the gas ejection hole. According to this, fluids ejected from the gas ejection holes collide with each other or interfere with each other, and even non-homogeneous fluids such as composition components or concentrations can be reliably mixed with little pressure loss.

  In addition, the gas mixer described in Patent Document 3 virtually arranges two quadrangular pyramids whose vertices abut each other in the gas flow direction inside the rectangular cylinder, and is disposed on one of the opposing surfaces of the respective quadrangular pyramids. The triangular plate is arranged, and the positions of the opposing faces of the quadrangular pyramids on which the inflow side and outflow side triangular plates are arranged are shifted by 90 ° from each other. According to this, the inflowing gas is divided into two gas flows by the inflow side quadrangular pyramid, twisted by 90 ° and introduced into the outflow side quadrangular pyramid, and the gas is mixed in the process. As a result, a gas mixer with low flow resistance can be realized.

Patent No. 4069196 JP 2000-233121 A JP 2002-306939 A Japanese Utility Model Publication No. 6-31826

  However, the gas mixer described in Patent Document 2 has a problem that the manufacture and assembly of the gas mixer become complicated because the shape of the fixed swirl vane differs depending on the radial position. In the gas mixers described in Patent Documents 3 and 4, gas mixing by swirling flow cannot be expected so much, so that the exhaust gas flow velocity in the flow passage cross section of the exhaust gas duct is equalized with a short duct length and at the entrance side of the denitration catalyst. If the ammonia / NOx molar ratio fluctuation rate (CV = standard deviation / average value) is to be made sufficiently low, there is a problem that the pressure loss increases and the fan power that induces exhaust gas increases.

  The problem to be solved by the present invention is that the manufacture and assembly are easy, the exhaust gas flow velocity in the cross section of the exhaust gas duct with a short duct length without increasing the power of the exhaust gas induction fan using the swirl flow of the gas. It is an object to provide an exhaust gas mixing device that can equalize the gas.

  In order to solve the above problems, the exhaust gas mixing apparatus of the present invention includes a plurality of gases provided in the flow passage cross section of the exhaust gas duct on the upstream side of the denitration device that reduces nitrogen oxides in the exhaust gas discharged from the combustion facility. The gas mixer is formed by arranging a plurality of triangular blades in a rectangular parallelepiped space, and the triangular blades are arranged at set points where one vertex corresponding to each other is defined in the rectangular parallelepiped space, Respective bottoms opposed to the apexes are arranged on the outer surface of the rectangular parallelepiped space parallel to the gas inflow direction, the blade surfaces are inclined at the same angle with respect to the axis of the gas inflow direction passing through the set point, and around the axis It is characterized by being rotated by equiangular pitches.

  That is, in the gas mixer of the present invention, one corresponding vertex of a plurality of triangular blades is positioned at the set point, and the bottom of the triangular blade facing the vertex is positioned on the outer surface of the rectangular parallelepiped space parallel to the gas inflow direction. The blade surfaces are inclined at the same angle with respect to the axis in the gas inflow direction, and are rotated around the axis by equal angular pitches. Therefore, in the exhaust gas flowing into the gas mixer, a swirling flow of a plurality of gases is formed around the axis by the blade surfaces of the plurality of triangular blades. Since the exhaust gas is mixed by the plurality of swirling flows, mixing of the reducing agent added to the exhaust gas and the exhaust gas is promoted. In addition, since a part of the exhaust gas flows away from the swirling flow and crosses the triangular blade, and a vortex is generated on the back side of the triangular blade, the mixing performance is improved.

  Further, if the gas mixers configured in this way are provided in multiple stages and arranged in a plurality of rows in the whole or a partial region of the cross section of the flow path of the exhaust gas duct, each gas mixer is configured. By the rectifying action that equalizes the pressure loss of the exhaust gas, the exhaust gas flow rate fluctuation rate (CV = standard deviation / average value) in the cross section of the exhaust gas duct upstream of the gas mixer can be reduced, and the exhaust gas flow rate is equalized. be able to. Furthermore, since the exhaust gas can be effectively mixed, the gas flow rate fluctuation rate (CV = standard deviation / average value) at the reducing agent addition position can be kept at a low value (for example, 15% or less). In particular, a denitration apparatus that can efficiently mix a small amount of reducing agent (ammonia) into exhaust gas can be constructed.

Thus, mixing of the reducing agent added to the exhaust gas and the exhaust gas is promoted, and the exhaust gas flow velocity in the cross section of the exhaust gas duct can be equalized. As a result, for example, the molar ratio variation rate (CV = standard deviation / average value) can be made uniform to a low value (for example, 7% or less). Further, the molar ratio can be made uniform with a short duct length by the action of mixing exhaust gases having different NOx concentrations with each other to make the NOx concentration uniform. Moreover, the gas can be mixed with a lower pressure loss than in the prior art. For example, the fluctuation rate of the molar ratio of NH ₃ / NOx is suppressed to 4% or less, the denitration performance is in the 90% range, and the slip ammonia concentration can be several ppm. Further, since the gas mixer having a simple structure can be realized by using the triangular blades formed in the same shape, the manufacture and assembly of the gas mixer can be further facilitated.

  In the present invention, the set point can be set on a central axis passing through the centers of the rectangular surfaces on the gas inflow side and gas outflow side of the rectangular parallelepiped space. The set point can be set at the center of the central axis, that is, the center of the rectangular parallelepiped space.

  The present invention can employ various modes as shown in Examples 1 to 8 and the like according to the arrangement of the triangular blades, the support structure of the triangular blades, and the shape of the triangular blades. For example, the number of triangular blades is typically preferably four, but the number is not limited to this. If pressure loss is allowed, triangular blades that are an integral multiple of that can be adopted. If there are four triangular blades, the exhaust gas flow inside the rectangular parallelepiped is divided into four, and the four divided flows are swirled by 90 ° and mixed.

  According to the present invention, it is easy to manufacture and assemble, and it is possible to equalize the exhaust gas flow velocity in the flow passage cross section of the exhaust gas duct with a short duct length without using the swirl flow of the gas and increasing the power of the exhaust gas induction fan. An exhaust gas mixing device can be provided.

It is a figure which shows the structure of Example 1 of the gas mixer of this invention. It is a figure explaining generation | occurrence | production of the vortex in the blade back in Example 1. FIG. It is a figure which shows the structure of the exhaust gas mixing apparatus which has arrange | positioned the gas mixer of Example 1 in the whole surface of the flow-path cross section of an exhaust gas duct. It is a figure which shows the structure of Example 2 of the gas mixer of this invention. It is a figure which shows the structure of Example 3 of the gas mixer of this invention. It is a figure which shows the structure of the exhaust gas mixing apparatus which has arrange | positioned the gas mixer of Example 3 in the whole surface of the flow-path cross section of an exhaust gas duct. It is a figure which shows the structure of Example 4 of the gas mixer of this invention. It is a figure which shows the structure of the exhaust gas mixing apparatus which has arrange | positioned the gas mixer of Example 4 in the whole surface of the flow-path cross section of an exhaust gas duct. It is a figure which shows the structure of Example 5 of the gas mixer of this invention. It is a figure which shows the structure of Example 6 of the gas mixer of this invention. It is a figure which shows the structure of Example 7 of the gas mixer of this invention. It is a figure which shows the detail of the notch part of each triangular blade | wing of Example 7. FIG. It is a figure explaining generation | occurrence | production of the vortex in the blade back in the triangular blade of Example 7. FIG. It is a figure which shows the detail of the notch part of each triangular blade | wing of the modification of Example 7. FIG. It is a figure which shows the structure of Example 8 of the gas mixer of this invention.

  Hereinafter, the present invention will be described based on examples.

  FIG. 1 is a perspective configuration diagram of a gas mixer according to a first embodiment of the present invention. The flow passage cross section of the denitration catalyst layer used in the large power generation facility is rectangular, and the flow passage cross section of the exhaust gas duct for introducing exhaust gas into the denitration catalyst layer is often rectangular. In addition, since the exhaust gas mixing device is installed in the entire flow passage cross section of the exhaust gas duct, the duct flow passage cross section is divided into a plurality of rectangular areas, and gas mixers of sizes corresponding to the rectangular areas are stacked in multiple stages. And a plurality of columns are arranged.

  Therefore, as shown in FIG. 1, the gas mixer 1 of the present embodiment is formed by arranging four triangular blades 3 (a to d) formed in the same shape in a rectangular parallelepiped space 2. . In addition, although shown separately, the rectangular tube 6 which forms the outer surface 5 (ad) parallel to the gas inflow direction (illustration arrow 4) of the rectangular parallelepiped space 2 is provided. The triangular blades 3 (a to d) are arranged at positions where the corresponding vertexes 01 of the triangular blades 3 (a to d) are in contact with each other, and each base 7 (a to d) facing the vertex 01 is The rectangular tube 6 is positioned in contact with the inner surface of the rectangular parallelepiped space parallel to the gas inflow direction. In addition, the base 7 (ad) of the triangular blade 3 (ad) is fixed to the inner surface of the rectangular tube 6 by spot welding or the like. In addition, the corresponding vertex 01 of the triangular blade 3 (ad) is fixed to a support member (not shown) (for example, a support rod) by welding or the like.

  In the present embodiment, the set point where the vertices 01 are in contact with each other is located at the center on the central axis 8 passing through the centers of the rectangular surfaces of the rectangular parallelepiped space 2 on the gas inflow side and the gas outflow side. Further, both ends of each base 7 (a to d) facing the vertex 01 are in contact with the inner surface of the rectangular cylinder 6 which is the outer surface of the rectangular parallelepiped space parallel to the gas inflow direction, and the gas inflow of the rectangular cylinder 6 Is located at the corner of the gas outlet and the gas outlet. Accordingly, the four triangular blades 3 (a to d) are inclined at the same angle with respect to the central axis 8 in the gas inflow direction passing through the set point, and rotate at equal angular pitches around the central axis 8. Has been placed.

  It is desirable to determine the external dimensions of the gas mixer 1 based on the dimensions of the flow path cross section of the exhaust gas duct to be installed. In particular, the size of the gas mixer 1 is determined in accordance with the shorter dimension of the vertical and horizontal dimensions of the duct channel cross section. For example, the cross-sectional size of the exhaust gas duct is 18.4 m wide × 4.6 m long. Then, considering the ease of manufacturing and maintainability, the vertical and horizontal dimensions D of the gas mixer 1 are set to 1 / n (where n is a natural number) of the shorter dimension of the duct channel cross section. In the present embodiment, the vertical and horizontal dimension D of the gas mixer 1 is a square of 2.3 m, which is a half of the length of 4.6 m. However, the present invention is not limited to this, and the dimensions of the gas mixer 1 can be appropriately set according to the exhaust gas flow rate, the molar ratio distribution, and the size of the adjustment region of the ammonia nozzle. In addition, the length L in the gas flow direction of the structure 1 may be 2.3 m so as to be a cube, or may be extended beyond that. As L / D increases, the pressure loss tends to decrease. However, since the gas flow rate fluctuation rate hardly decreases, the pressure loss can be increased or decreased in accordance with the specified pressure loss.

  Moreover, since the gas mixer 1 of the present embodiment forms a swirling gas flow around the central axis 8, it is desirable that the gas mixer 1 has a square cross section when viewed from the gas flow direction. However, the aspect ratio may be slightly changed according to the cross-sectional size of the exhaust gas duct.

  In addition, although there are three vertices of the triangle blade 3 geometrically, including the present embodiment, in this specification, only the vertex positioned at the center of the rectangular parallelepiped space 2 is referred to as a vertex 01, and the other vertices are referred to. Will be described as both ends of the bottom facing the vertex 01. Note that the vertex 01 is not necessarily set at the center of the rectangular parallelepiped space 2, and may be set at any position on the center line 8. Further, although it is not always necessary to set it on the center line 8, it is preferable that the center line or the center line 8 be taken into consideration in terms of ease of manufacture.

  As described above, in the first embodiment, the corresponding vertex 01 of the plurality of triangular blades 3 (ad) formed in the same shape is positioned at the center point (set point) on the center axis 8. The rectangular cylinder 6 positioned at the outer surface 5 (ad) of the rectangular parallelepiped space 2 parallel to the gas inflow direction with the base 7 (ad) of the triangular blade 3 (ad) facing the apex 01 Since both ends of the base 7 (ad) are positioned at the corners on the gas inflow side and the gas outflow side of the rectangular tube 6, the vane surface with respect to the central axis 8 in the gas inflow direction. Are inclined at the same angle, and are rotated by an equiangular pitch around the axis. Therefore, the exhaust gas flowing into the gas mixer 1 is divided into four by the blade surfaces of the plurality of triangular blades 3 (ad), and each of the four gases is rotated by 90 ° around the central axis 8 and flows out. The swirling flow is formed. Since the exhaust gas is mixed by the four swirl flows, mixing of the reducing agent added to the exhaust gas and the exhaust gas is promoted. In addition, since a part of the exhaust gas flows away from the swirling flow and over the triangular blades 3 (a to d), vortices are generated on the back side of the triangular blades, so that the mixing performance is improved.

  FIG. 2 is a diagram for explaining the vortex flow generated on the back surface of the triangular blade 3 according to the first embodiment. A vortex is generated from a flow passing through the triangular blade 3 arranged obliquely with respect to the gas flow. Thereby, there exists an effect which mixing of exhaust gas is accelerated | stimulated. In addition, as shown in the following Example 2, when the support pipe 9 (ad) is provided at the edge of the triangular blade 3 on the gas inflow side, the gas flow over the support pipe 9 (ad) is further increased. Since the vortex is generated, the mixing of the exhaust gas is further promoted.

  An example of the exhaust gas mixing apparatus in which the gas mixer 1 of the present embodiment is configured as a lattice element is shown in FIG. That is, in this example, the gas mixers 1 are arranged on the entire cross section in the exhaust gas duct 25 on the upstream side of the denitration apparatus so as to be adjacent to each other. In the first embodiment, the rectangular cylindrical body 6 surrounds the structure of the triangular blades 3 (a to d), and thus, as shown in FIG.

  In FIG. 4, the perspective block diagram of the gas mixer 21 of Example 2 is shown. This embodiment is different from the first embodiment in that support pipes 9 (a to d) that are support rods for reinforcing the support of the triangular blades 3 (a to d) are provided, and the gas flow of the gas mixer 21. The perspective view block diagram of the gas mixer 21 of Example 2 which made the length L of the direction 4 m is shown. This embodiment is different from the first embodiment in that support pipes 9 (a to d) that are support rods for reinforcing the support of the triangular blades 3 (a to d) are provided, and the gas flow of the gas mixer 21. Since the length of the direction is L = 4 m and the other configuration is the same as that of the first embodiment, the same reference numerals are given and the description thereof is omitted.

  In Example 1, the support of the triangular blades 3 (a to d) is shown as being fixed to the inner surface of the rectangular cylinder 6 by welding or the like. In the second embodiment, both ends of the base 7 (ad) of the triangular blade 3 (ad) are positioned at the corners on the gas inflow side and the gas outflow side of the rectangular cylinder 6, and at the apex 01. In view of the fact that the connected hypotenuses are in contact with the internal diagonal line of the rectangular tube body 6, the support pipes 9 (a to d), which are support rods, are welded to the corners of the rectangular tube body 6 to create a support frame along the internal diagonal line. . Thereby, since it contacts two support pipes among the support pipes 9 (ad) in which the two hypotenuses of each triangular blade 3 (ad) intersect, each triangular blade of the support pipe 9 (ad) The supporting strength of the triangular blades 3 (ad) can be reinforced by welding the two oblique sides 3 (ad).

  In FIG. 5, the perspective block diagram of the gas mixer 31 of Example 3 is shown. The difference between the present embodiment and the second embodiment is that, as shown in the drawing, instead of configuring the outer wall of the gas mixer 31 with the rectangular tube body 6, a pair corresponding to the upper and lower ceiling surfaces and the bottom surface facing each other in the figure. The flat plate 32 (a, b) is provided. Since the other points are the same as in the second embodiment, the same reference numerals are given and the description thereof is omitted.

  In this embodiment, the bases 7a and 7c of the triangular blades 3a and 3c are in contact with the pair of flat plates 32 (a and b), respectively. Therefore, the bases 7a and 7c are connected to the pair of flat plates 32 ( We fix it at several points to a and b). By welding the two hypotenuses of each triangular blade 3 (ad) to the support pipe 9 (ad), the supporting strength of the triangular blade 3 (ad) is ensured. That is, since the triangular blades 3 (a to d) can be supported on the support pipes 9 (a to d) provided along the internal diagonal line of the rectangular tube 6, the strength that can withstand the pressure received from the exhaust gas flow is obtained. Can be obtained.

  FIG. 6 shows an example of an exhaust gas mixing apparatus in which the gas mixer 31 of the third embodiment is configured as a lattice element. That is, in this example, the gas mixers 31 are arranged on the entire cross section in the exhaust gas duct 25 on the upstream side of the denitration apparatus so as to be adjacent to each other. In the third embodiment, the pair of flat plates 32 (a, b) surrounds the structure of the triangular blades 3 (a to d).

  In FIG. 7, the perspective block diagram of the gas mixer 41 of Example 4 is shown. This embodiment differs from the third embodiment in that the pair of flat plates 32 (a, b) is omitted. In order to compensate for the reduced support strength, the present embodiment, as shown in the figure, for example, one end of the bottom 7a of the triangular blade 3a located at the corner of the gas inflow end and the outflow end of the gas mixer 41 and the triangular blade A support pipe 42a for connecting one end of the bottom 7b of 3b is provided. Similarly, the support pipes 42 (ad) are provided at the four ridge lines parallel to the gas inflow direction of the rectangular parallelepiped space 2, and both ends of the triangular blades 3 (ad) at the corresponding positions are provided. One ends of the bottom sides 7 (a to d) are connected to each other. Since the other points are the same as those of the third embodiment, the same reference numerals are given and description thereof is omitted.

  The gas mixer 41 according to the fourth embodiment secures the strength by the structure that supports the triangular blades 3 (ad) with the support pipes 9 (ad) and the support pipes (ad), and is completely partitioned. It is characterized by having no configuration.

  An example of the exhaust gas mixing apparatus in which the gas mixer 41 of the fourth embodiment is configured as a lattice element is shown in FIG. That is, in this example, the gas mixers 41 are arranged on the entire cross section in the exhaust gas duct 25 on the upstream side of the denitration apparatus so as to be adjacent to each other. Since the gas mixer 41 of Example 4 has only a support structure composed of the triangular blades 3 (ad), the support pipes 9 (ad), and the support pipes 42 (ad), as shown in FIG. Become.

  In FIG. 9, the perspective block diagram of the gas mixer 51 of Example 5 is shown. This embodiment is different from the first and second embodiments in that a cross-shaped support pipe 52 (a, b) which is a cross-shaped support rod is formed on a line connecting the centers of two opposite sides of the rectangular surface on the gas outflow side of the rectangular parallelepiped space 2. ) And each vertex 01 of the triangular blades 53 (ad) formed in the same shape is an intersection 54 of the cruciform support pipe 52 (a, b) located on the central axis 8 in the gas inflow direction. Are arranged so as to contact each other. Since the other points are configured in the same manner as in the first and second embodiments, the same reference numerals are given and description thereof is omitted. That is, the gas mixer 51 is configured by assembling the triangular blades 52 (a to d) inside the rectangular tube body 6.

  Since the triangular blades 53 (a to d) of the fifth embodiment are arranged so that the bottoms facing the vertex 01 are in contact with the inner surface of the rectangular tube 6, the inner surfaces of the rectangular tube 6 along the bottom. And the triangular blade 53 (ad) are welded and connected at several points. Further, since the hypotenuses connected to the apex 01 of the triangular blades 53 (ad) are arranged in contact with the cruciform support pipes 52 (a, b), they are connected by welding at some points. . Furthermore, if necessary, the support pipe 55 (ad) is connected to the intersection 54 of the cruciform support pipe 52 and the rectangular tube body 6 along the other hypotenuse connected to the vertex 01 of the triangular blade 53 (ad). It is provided between the corners on the gas inflow side and can be connected to the support pipe 55 (ad) by welding the other oblique sides of the triangular blades 53 (ad).

  In the triangular blades 53 (a to d) of the fifth embodiment, one end of each of the bottoms facing the apex 01 is positioned at one end of the gas inflow side of the rectangular tube 6, and the other end is a rectangular tube. It is located in the center of one side of the gas outflow side of the body 6. Further, a cruciform support pipe 52 is provided on a line connecting the centers of two opposing sides of the rectangular surface on the gas outflow side of the rectangular parallelepiped space 2, and the triangular blades 53 (ad) are connected to the vertex 01 and the vertex 01, respectively. One oblique side is fixed to the cross-shaped support pipe 52.

  That is, the gas mixer 51 of the fifth embodiment corresponds to a shape in which the latter half portion is deleted in the gas flow direction of the triangular blades of the gas mixer 1 of the first embodiment. Thereby, according to Example 5, although the gas turning force becomes lower than that of the gas mixer 1 of Example 1 or the like, the length of the gas mixer in the gas flow direction is halved, so that the pressure loss is reduced. There is an effect of lowering. This is desirable because the pressure loss can be reduced and the gas flow rate fluctuation rate can be reduced.

  In FIG. 10, the perspective block diagram of the gas mixer 61 of Example 6 is shown. In this embodiment, as shown in the figure, instead of configuring the outer wall of the gas mixer 61 with the rectangular tube 6 as shown in the figure, a pair of upper and lower ceiling surfaces and bottom surfaces corresponding to each other in the figure. The difference is that the flat plates 32 (a, b) are provided. Further, in order to ensure the strength of the gas mixer 61, vertical support pipes 62 (provided on lines passing through opposite corners of the gas outflow side of the pair of flat plates 32 (a, b) and both ends of the cross-shaped support pipe 52b ( a, b) and a vertical support pipe 62 (a, b) and a cross-shaped support pipe 52b at positions on the outer surface parallel to the gas inflow direction of the rectangular parallelepiped space where the pair of flat plates 32 (a, b) are not arranged. And an inclined support pipe 64 (ad) provided on a line connecting the gas inflow side corners of the pair of flat plates 32 (a, b) and the triangular blades 53 (ad). The difference is that the bases not fixed to the pair of flat plates 32 (a, b) are fixed to the inclined support pipes 64a, 64d. Since the other points are the same as those of the fifth embodiment, the same reference numerals are given and the description thereof is omitted.

  That is, the gas mixer 61 according to the sixth embodiment has a configuration in which the vertical partition of the rectangular tube 6 constituting the rectangular parallelepiped space 2 is omitted and there is no vertical partition. According to the present embodiment, the strength can be improved as compared with the gas mixer 31 of the third embodiment shown in FIG. Although the pair of horizontal plates 32 (a, b) may be omitted as in the fourth embodiment, it is necessary to reinforce the frame with a support pipe or the like as necessary.

  In FIG. 11, the perspective block diagram of the gas mixer 71 of Example 7 is shown. This embodiment is different from the fifth and sixth embodiments in that a triangular notch 74 is formed on a side 73 having one end at the apex 01 of the triangular blade 72 (ad). Since the other points are the same as those of the fifth and sixth embodiments, the same reference numerals are given and the description thereof is omitted.

  The notch 74 is formed as shown in FIG. That is, the side 73 of the notch 74 coincides with the side 73 of the triangular blade 72. In other words, one end of the side 73 of the notch 74 coincides with the apex 02 on the gas inflow side, and the other end of the side 73 of the notch 74 coincides with the apex 01 on the gas outflow side of the triangular blade 72. . Then, a division point 04 is set by dividing the side 73 from the vertex 02 to the vertex 01 into an A: B ratio. The vertex 05 of the notch 74 is set on a line 75 connecting the vertex 03 of the triangular blade 72 and the segment point 04. At this time, the dividing point dividing the straight line 75 connecting the vertex 03 and the dividing point 04 located on the gas outflow side into C: D is defined as the apex 05. The triangular portion formed by connecting the vertices 01 and 02 and the vertex 05 of the side 73 of the triangular blade 72 is cut out as a cutout portion 74.

  Here, various values can be adopted as the ratio of A: B and C: D. For example, the ratio of A: B is 3-7: 7-3, and the ratio of C: D is 3-9: It is desirable to be between 7 and 1. More preferably, A: B is 4-6: 6-4, and C: D is 5-9: 5-1. However, it is desirable that the angle E on the gas inflow side of the triangular blade 72 of the remaining notch portion should not be 10 degrees or less. This is because vortex generation described later does not occur even when the angle E is extremely sharp. The angle E is preferably selected within the range of 10 to 45 °, and the angle F shown in the figure is selected within the range of 45 to 80 °. The angle F is an angle formed by an extension line of the line connecting the vertex 01 and the vertex 05 with a line connecting the vertex 02 and the vertex 03. For example, in Example 7, E = 15 ° and F = 45 ° are set.

  With this configuration, according to the gas mixer 71 of Example 7, the angle E on the gas inflow side of the triangular blade 72 is an acute angle, and the angle on the gas outflow side is an obtuse angle, which is shown in FIG. As described above, the vortex flow of the gas generated over the triangular blade 72 is generated in each portion, and the mixing performance is further enhanced. Further, according to this embodiment, the projected area of the triangular blade 72 is reduced, so that the pressure loss is reduced. Note that an angle F in FIG. 14 is an angle formed by an extension line of a line connecting the segment point 06 and the vertex 05 with a line connecting the vertex 02 and the vertex 03.

  Further, FIG. 14 shows a modification of the notch portion of the seventh embodiment. As shown in the figure, division points 04 and 06 are set by dividing the base 73 into a ratio of A: B: B2. Then, the triangular notch 76 formed by connecting the vertices 02, 05, 06 is deleted. According to this modification, since the gradient is divided into three steps, a complicated swirl flow is generated, and the mixing effect is increased.

  The shape of the notch shown in the seventh embodiment and its modification is not limited to those embodiments and the like. In short, the shape is similar to the triangle formed on the base opposite to the apex of each triangular blade. In the case of a cutout portion having a shape, for example, a shape formed by a curve, the mixing effect is similarly increased.

  In FIG. 15, the perspective block diagram of the gas mixer 81 of Example 8 is shown. This embodiment is different from the other embodiments in that an opening (for example, φ600 mm) 63 is formed in the central portion of the triangular blade 82, and other configurations are the same as those in the first to sixth embodiments. Description is omitted. According to the present embodiment, the gas flow passing through the opening 63 and the gas flow flowing along the triangular blade 82 collide in a complicated manner, and the mixing effect can be enhanced. A plurality of openings 63 may be provided. Further, since the projected area of the triangular blade 82 is reduced, there is an effect that the pressure loss is reduced.

  As mentioned above, although the gas mixer of this invention was demonstrated based on the Example, this invention is not limited to this. In short, in the exhaust gas mixing apparatus for a denitration apparatus provided with a plurality of gas mixers provided in the flow passage cross section of the exhaust gas duct on the upstream side of the denitration apparatus that reduces nitrogen oxides in the exhaust gas discharged from the combustion facility, The gas mixer is formed by arranging a plurality of triangular blades formed in the same shape in a rectangular parallelepiped space, and the triangular blades are in contact with each other at a set point whose corresponding vertex is determined in the rectangular parallelepiped space. Each of the bottoms facing the apex is positioned on the outer surface of the rectangular parallelepiped space parallel to the gas inflow direction, the blade surface is inclined at the same angle with respect to the axis of the gas inflow direction passing through the set point, and It is characterized by being rotated around the axis by equal angular pitch.

  In this case, the set point may be an arbitrary position on the central axis passing through the centers of the rectangular surfaces on the gas inflow side and the gas outflow side of the rectangular parallelepiped space, or the center of the central axis or the rectangular surface on the gas outflow side. Can be set to the center.

  Further, the gas mixer of the present invention may be formed by surrounding a plurality of triangular blades by surrounding the rectangular tube 6 as shown in the first embodiment or the like, as shown in the embodiment of FIGS. The upper and lower surfaces or the left and right surfaces of the triangular blades may be enclosed, and the periphery of the plurality of triangular blades may be opened as shown in Example 4 of FIG. Good. In short, it is only necessary to fix and support a plurality of triangular blades shown in each embodiment. For example, as shown in Example 4 of FIG. 7, in the case where only the triangular blades and the support pipe are used, the gas flows swirling inside the adjacent gas mixers are mixed with each other and uniformized over a wider range. Increases effectiveness. However, since the swirl flow of gas becomes strong, when aiming to reduce the gas flow rate fluctuation rate, as shown in Example 1 or the like, the rectangular cylinder 6 surrounds four surfaces, or in FIGS. There are cases where it is better to have two sides as in the embodiment.

  Here, the gas mixer of Examples 1 to 8 of the present invention, Comparative Example 1 in which no gas mixer is disposed, and the gas mixer included in the filler having the cross-path structure described in JP-A-2000-233130 are provided. Comparative Example 2 arranged and Comparative Example 3 arranged with the gas mixer of Patent Document 3 are arranged in the same exhaust gas flow passage cross section, and the ammonia / NOx molar ratio variation rate (CV), gas flow rate variation rate ( Table 1 shows the results of comparing CV) and pressure loss.

  For the comparison, numerical analysis software FLUENT Ver6 was used, and an initial value was given such that the fluctuation rate of the gas flow rate at the inlet surface (hereinafter referred to as gas flow rate CV) was 20%. The ammonia nozzle also uses a structure that reproduces the actual machine size, and the conditions for changing the ammonia injection amount in accordance with the inlet gas flow rate.

  Example 1 resulted in the highest molar ratio CV, but the normally required molar ratio CV ≦ 7% was cleared. However, there was a problem with high pressure loss. In Examples 6, 7, and 8, the pressure loss was low, and it was found that both the molar ratio CV and the gas flow rate CV could clear the target. In any of the examples, the molar ratio CV clears the target, and can be selected according to the pressure drop tolerance.

On the other hand, since the gas mixer was not installed in Comparative Example 1, there was no problem with the gas flow rate CV, but the molar ratio CV was the highest at 9.2% and the normally required 7% was not satisfied. In Comparative Example 2, the molar ratio CV hardly changes, and the effect is small as compared with the example of the present invention. Comparative Example 3 mainly has the effect of restricting the gas flow, and is not a structure that gives a large swirling flow to the gas flow. Therefore, although the target value of the molar ratio CV is cleared, it is higher than Examples 2-8. Yes, it was found to belong to a class with high pressure loss.
From the above, it was found that the effects of Examples 5 to 8 were particularly high and the mixer was effective.

  As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to these, It is possible to implement in the form deform | transformed or changed in the range of the main point of this invention. It will be obvious to those skilled in the art, and it is obvious that such modifications or alterations belong to the scope of the claims of the present application.

DESCRIPTION OF SYMBOLS 1 Gas mixer 2 Cuboid space 3 (ad) Triangular blade 4 Gas inflow direction 5 (ad) Outer surface 6 Square cylinder 7 (ad) Bottom 8 Central axis 9 (ad) Support pipe 01 Apex

Claims (19)

In the exhaust gas mixing device comprising a plurality of gas mixers provided in the cross section of the exhaust gas duct on the upstream side of the denitration device that reduces nitrogen oxides in the exhaust gas discharged from the combustion facility,
The gas mixer is formed by arranging a plurality of triangular blades in a rectangular parallelepiped space,
The triangular blades are arranged at a set point where one vertex corresponding to each other is defined in the rectangular parallelepiped space, and each base opposite to the vertex is arranged on an outer surface of the rectangular parallelepiped space parallel to the gas inflow direction, An exhaust gas mixing apparatus, characterized in that a blade surface is inclined at the same angle with respect to an axis in a gas inflow direction passing through a point and is rotated by an equal angular pitch around the axis.   2. The exhaust gas mixing apparatus according to claim 1, wherein the set point is set on a central axis passing through a center of a rectangular surface on the gas inflow side and the gas outflow side of the rectangular parallelepiped space. The gas mixer includes a rectangular tube forming an outer surface parallel to a gas inflow direction of the rectangular parallelepiped space,
3. The exhaust gas mixing apparatus according to claim 1, wherein the triangular blades are supported by fixing the apexes to each other and fixing a base opposite to the apexes to an inner surface of the rectangular tube body. .   The triangular blade has one end of each bottom side facing the apex located on one side of the gas inflow side of the rectangular tube, and the other end located on one side of the gas outflow side of the square tube. The exhaust gas mixing device according to claim 3, wherein the exhaust gas mixing device is provided.   The triangular blade has one end of each bottom side facing the apex located at one end of the gas inflow side of the rectangular tube, and the other end is one side of the gas outflow side of the square tube The exhaust gas mixing device according to claim 4, wherein the exhaust gas mixing device is located at an opposite end of the exhaust gas.   The triangular blade has one end of each bottom side facing the apex located at one end of the gas inflow side of the rectangular tube, and the other end is one side of the gas outflow side of the square tube The exhaust gas mixing device according to claim 4, wherein the exhaust gas mixing device is located in the center of the exhaust gas. The gas mixer is provided with a cross-shaped support rod on a line connecting the centers of two opposite sides of the rectangular surface on the gas outflow side of the rectangular parallelepiped space,
The exhaust gas mixing device according to claim 6, wherein each of the triangular blades is fixed to the cross-shaped support rod at the apex and one oblique side connected to the apex.   The triangular blade is fixed to two support rods provided so that at least one of the hypotenuses intersects at the apex among the two hypotenuses excluding the bottom side fixed to the inner surface of the rectangular tube body. The exhaust gas mixing apparatus according to any one of claims 3 to 6.   9. The exhaust gas according to claim 8, wherein the support rod is provided on a line connecting the gas inflow side, the gas outflow side corner of the rectangular tube, and the apex of the triangular blade. Mixing device. The gas mixer has a pair of flat plates arranged on opposing surfaces parallel to the gas inflow direction of the rectangular parallelepiped space,
Support bars are respectively provided on lines connecting the corners of the pair of flat plates and the apexes of the triangular blades,
3. The exhaust gas mixing apparatus according to claim 1, wherein each of the triangular blades has an apex and a hypotenuse connected to the apex fixed to the support rod, and the base is fixed to the flat plate. The gas mixer is provided with a ridge line support bar provided on a ridge line parallel to the gas inflow direction of the rectangular parallelepiped space, and a support bar on a line connecting both ends of the ridge line support bar and the apex of the triangular blade. And
3. The exhaust gas mixing apparatus according to claim 1, wherein each of the triangular blades is fixed to the support member at the apex and a hypotenuse connected to the apex. The gas mixer has a pair of flat plates arranged on opposing surfaces parallel to the gas inflow direction of the rectangular parallelepiped space, and a cruciform support on a line connecting the centers of two opposing sides of the rectangular surface on the gas outflow side of the rectangular parallelepiped space A bar is provided,
3. The triangle blade according to claim 1, wherein the triangular blades are fixed to the pair of flat plates, and each of the apex and one oblique side connected to the apex is fixed to the cross-shaped support rod. The exhaust gas mixing apparatus as described. The gas mixer includes a vertical support bar provided on a line passing through opposite ends of the gas outflow side of the pair of flat plates and both ends of the cross-shaped support bar, and the rectangular parallelepiped space in which the pair of flat plates are not disposed. An inclined support bar provided on a line connecting an intersection of the vertical support bar and the cross-shaped support bar and a corner on the gas inflow side of the pair of flat plates at a position of the outer surface parallel to the gas inflow direction of ,
The exhaust gas mixing apparatus according to claim 12, wherein the triangular blades are fixed to the inclined support rods at the bottoms that are not fixed to the pair of flat plates.   The exhaust gas mixing device according to any one of claims 1 to 13, wherein the triangular blade has at least one opening formed on a blade surface.   The exhaust gas mixing apparatus according to any one of claims 1 to 13, wherein the triangular blade has a triangular notch formed on a bottom side facing the apex. The apex of the notch is set on a line connecting a dividing point where the base of the triangular blade is divided into a ratio of A: B from one end to the other end on the gas inflow side and the apex of the triangular blade. And
One end of the bottom of the notch coincides with one end on the gas inflow side of the bottom of the triangular blade, and the other end of the bottom of the notch coincides with one end on the gas outflow side of the bottom of the triangular blade The exhaust gas mixing apparatus according to claim 15, wherein The apex of the notch is set on a line connecting the A: B segmentation point, which divides the base into a ratio of A: B: B2, and the apex of the triangular blade,
One end of the bottom of the notch coincides with one end on the gas inflow side of the bottom of the triangular blade, and the other end of the bottom of the notch coincides with a B: B2 dividing point. The exhaust gas mixing apparatus according to claim 15.   The vertex of the notch is set to a dividing point obtained by dividing a line connecting the A: B dividing point and the apex of the triangular blade into a ratio of C: D. The exhaust gas mixing device according to 1.   The gas mixer according to any one of claims 1 to 18, wherein a plurality of stages and a plurality of rows are arranged in at least a part of a cross section of a flow path of an exhaust gas duct on the upstream side of the denitration apparatus. A featured exhaust gas treatment device.

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