JP2006181424A - Gas mixer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas mixer which uniformly disperses gas to be diluted with simple and compact structure, and is excellent in maintenability. <P>SOLUTION: The gas mixer is constituted so that two supply pipes 2 of gas to be diluted are separately inserted into a gas duct in the gas flow direction through the gas duct side face, such that the two pipes form a cross pattern when seen from the upstream side of the duct 1, dispersion holes 3 are provided to jet the gas to be diluted to the downstream side and both side faces of the supply pipes 2 of gas to be diluted, and at least two mixing plates 5 consisting of cross-patterned shielding vanes are installed in the downstream side of the supply pipes 2. The alternate arrangement of the dispersion holes 3 of the supply pipes 2 in the the downstream side of the gas flow and both side faces heightens the dispersion of the gas, and allows to cope with a high ratio of the gas to be diluted to a main gas flow. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas mixer, and particularly to a gas mixer that is suitable when the flow range of a gas to be diluted is wide, has high mixing properties, is compact, and has excellent maintainability.

A known example of a prior art gas mixer is shown in FIGS.
3 is a view of the inside of the gas mixer (FIG. 3 (a)) and an arrow view of the AA line (FIG. 3 (b)) viewed from the downstream side of the gas flow of FIG. 3 (a). It is shown.

  The gas mixer shown in FIG. 3 is composed of a gas mixture body 1 and a dilution gas supply pipe 2 having a dispersion hole 3, and the dilution gas supply pipe up to almost the center of the gas mixer body 1 through which the mainstream gas flows. 2 is inserted, and the gas to be diluted is to be dispersed, mixed and diluted through the dispersion hole 3 provided in the gas to be diluted gas supply pipe 2. However, the dispersion and mixing properties of the dilution gas are poor, and the concentration distribution of the dilution gas will occur in the mainstream gas, so that the dilution gas will be installed downstream of the gas mixer. Problems such as performance degradation in a reactor that has not been diluted and leakage of diluted gas occur. However, if the distance from the dispersion hole 3 to the reactor (not shown) is increased, the concentration distribution of the diluted gas can be made uniform to some extent, but the overall system size including the mixer and the reactor is large. End up.

  As countermeasures, FIG. 4 (a view of the inside of the gas mixer (FIG. 4A)) and arrows AA and BB viewed from the downstream side of the gas flow in FIG. As shown in the visual views (FIGS. 4B and 4C), a general mixer 4 having a three-dimensional structure between the dispersion hole 3 of the diluted gas supply pipe 2 and a reaction apparatus (not shown). However, in general, the three-dimensional mixer 4 has a large pressure loss, and poor maintainability when dust in the mainstream gas adheres.

  Further, the configuration shown in FIG. 4 is difficult to cope with a wide range of operating conditions and a ratio of the dilution gas to the mainstream gas that varies between several% to 50%, and in particular, the ratio of the dilution gas is high. Under the conditions, the pressure loss of the dispersion hole 3 becomes high, and the flow rate of the diluted gas cannot be secured. If the diluted gas supply pipe 2 is thickened and the dispersion holes 3 are enlarged, the problem of securing the flow rate can be dealt with. However, it is difficult to improve the dispersibility / mixability without considering the arrangement of the dispersion holes 3. Further, if only the arrangement of the dispersion holes 3 is taken into account, the structure of the dilution gas supply pipe 2 becomes complicated, and maintenance performance is lacking.

Japanese Patent Laid-Open No. 2002-306938 discloses FIG. 5 (a view of the inside of the gas mixer (FIG. 5A)) and an AA line arrow viewed from the upstream side of the gas flow of FIG. 5A. As shown in FIG. 5 (b), a cross-shaped diluted gas pipe 2 is provided for the mainstream gas flowing in the gas mixer body 1, and the upstream side of the gas flow in the diluted gas pipe 2 is provided. The gas to be diluted is jetted from the jet hole 6 and the central hole 7 facing toward the center, and two columns 8 and 8 for gas flow agitation are orthogonal to each other at intervals in the gas flow direction of the main flow gas at the downstream part thereof. An apparatus for mixing fluids such as gases in a direction is disclosed.
JP 2002-306938 A

  The prior art shown in FIG. 3 and FIG. 4 does not give sufficient consideration to measures for uniformly supplying the gas to the mainstream gas, or to a condition where the ratio of the dilution gas to the mainstream gas is high, Not only the mixer but also the compactness of the entire system is impaired, and problems such as an increase in pressure loss of the system may occur.

  Moreover, since the invention described in Patent Document 1 is configured to eject the diluted gas from the cross-shaped diluted gas pipe 2 toward the upstream side of the gas flow, the diluted gas is disposed in the gas mixer main body 1. If it is not blown out with a sufficiently large jet energy relative to the gas flow, mixing with the mainstream gas will be insufficient. Further, since the ejection holes 6 and 7 for the gas to be diluted are arranged in the direction facing the gas flow of the mainstream gas, it is necessary to keep cleaning at all times because they are easily clogged.

  An object of the present invention is to solve the above problems, and to provide a gas mixer that can uniformly disperse a gas to be diluted with a simple and compact structure and that is excellent in maintainability.

The above object of the present invention is achieved by the following means.
The invention according to claim 1 is a mixer for supplying a gas to be diluted into a duct through which a main gas flows, and mixing both gases. When viewed from the upstream side of the duct, the gas to be diluted is two. Each dilution gas supply pipe is shifted in the gas flow direction and inserted into the duct from the side of the duct so that the supply pipe has a cross shape, and the dilution gas is supplied to the downstream side and both side faces of the dilution gas supply pipe. The gas mixer is provided with a dispersion hole to be ejected, and further provided with at least one mixing plate composed of a cross-shaped shielding blade on the downstream side of the diluted gas supply pipe.

  According to a second aspect of the present invention, there is provided the gas mixer according to the first aspect, wherein the dilution gas supply pipe has a straight pipe shape, and the dispersion holes are alternately arranged on the gas flow downstream side and the side surface side. is there.

  According to a third aspect of the present invention, in the mixing plate according to any one of the first and second aspects, the mixing plate includes a flat shield blade that does not give a swirling action to the main gas flow and generates a vortex downstream of the shield blade. It is a gas mixer.

  According to a fourth aspect of the present invention, when the dilution gas supply pipe and the mixing plate are viewed from the upstream side of the duct, the dilution gas supply pipe and the mixing blade are arranged so as not to overlap each other. Or a gas mixer according to any one of 3 to 3.

  According to a fifth aspect of the present invention, the two or more mixing plates are arranged so as to be shifted so that the shielding blade portions of adjacent mixing plates do not overlap when viewed from the upstream side of the duct. 4. The gas mixer according to any one of 3.

(Function)
According to the first aspect of the present invention, the number and size of the dispersion holes of the dilution gas supply pipe can be sufficiently secured, the gas dispersibility in one dilution gas supply pipe can be enhanced, and the dilution of mainstream gas can be achieved. It becomes possible to cope with conditions where the ratio of gas is high.

  According to the invention described in claim 2, in addition to the operation of the invention described in claim 1, since the diluted gas supply pipe has a straight pipe shape, the diluted gas supply pipe is pulled out from the duct when the apparatus is stopped. The dispersion hole can be easily cleaned. Further, since the dispersion holes of the diluted gas supply pipe are not provided in the flow direction of the mainstream gas, solid matter contained in the mainstream gas is less likely to enter the dispersion holes, and the maintenance is excellent.

  According to the invention described in claim 3, in addition to the operation of the invention described in claims 1 and 2, the gas mixing property on the downstream side of the mixing plate is further improved.

  According to the invention described in claim 4, in addition to the operation of any one of the inventions described in claims 1 to 3, when the diluted gas supply pipe and the mixing plate are viewed from the upstream side of the duct, the dispersion holes and the mixing are provided. Since the shield blades of the plate are arranged so as not to overlap, the gas blow-out to the area where the dispersion holes are not prevented is prevented, and mixing of the mainstream gas and the gas to be diluted is not hindered. .

  According to the invention described in claim 5, in addition to the operation of any one of the inventions described in claims 1 to 3, when a plurality of mixing plates are installed and viewed from the upstream side of the duct, adjacent mixing plates It is possible to obtain a higher mixing property by arranging the shield blades so as not to overlap each other.

  According to the first aspect of the present invention, the dilution gas can be uniformly distributed and supplied to the mainstream gas, and can flexibly cope with the condition where the ratio of the dilution gas to the mainstream gas is high, and has a simple and compact structure. A gas mixer can be provided.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, it is possible to provide a gas mixer having excellent maintainability.

  According to the third aspect of the invention, in addition to the effects of the first and second aspects of the invention, the gas mixing property on the downstream side of the mixing plate is improved, so that the mainstream gas and the gas to be diluted are uniformly mixed. It becomes easy.

  According to the invention described in claim 4, in addition to the effects of any one of the inventions described in claims 1 to 3, since the dispersion hole and the shielding blade portion of the mixing plate are arranged so as not to overlap, the dispersion hole is not formed. Blowing of the gas to the area where it is not arranged is prevented, and the mixing property of the mainstream gas and the gas to be diluted is further improved.

  According to the fifth aspect of the invention, in addition to the effects of any of the first to third aspects of the invention, the shielding blades between the mixing plates are arranged so that they do not overlap. Can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a view of the inside of a gas mixer according to an embodiment of the present invention (FIG. 1 (a)) and an AA line and BB seen from the downstream side of the gas flow of FIG. 1 (a). Each arrow figure (FIG.1 (b)-FIG.1 (d)) of the line and CC line was shown. The mixer in the embodiment shown in FIGS. 1 and 2 of the present invention is called a mixing plate 5 in order to clearly distinguish it from the prior art mixer 4 shown in FIGS.

  In FIG. 1, the diluted gas supply pipes 2 are spaced in the direction of gas flow in the direction crossing the gas mixer body 1 through which the mainstream gas flows, and are inserted in directions orthogonal to each other. That is, when the mixer main body 1 is viewed from the upstream side of the gas flow, the gas flow in each dilution gas supply pipe 2 so that the two straight pipe-shaped dilution gas supply pipes 2 form a cross shape. It is inserted in the mixer main body 1 from the side of the mixer main body 1 while being shifted in the direction.

  The dilution gas supply pipe 2 is provided with a plurality of dispersion holes 3 at predetermined intervals, and the dispersion holes 3 are arranged in a direction in which the dilution gas is ejected to the downstream side and both side surfaces of the dilution gas supply pipe 2. Is provided. Further, the gas discharge direction of the dispersion hole 3 is sequentially arranged in the longitudinal direction of the diluted gas supply pipe 2 so that the gas ejection direction is alternately arranged on the gas flow downstream side and the side facing the inner wall surface of the mixer body 1. However, this is different from the prior art shown in FIGS.

  Further, a gas mixer in which a cross-shaped mixing plate 5 in which two flat plates are stacked is orthogonal to the downstream side in the gas mixer body 1 where the two dilution gas supply pipes 2 are arranged. It is provided in a direction crossing the inside of the main body 1.

  In the embodiment shown in FIG. 1, the dispersion holes 3 through which the gas to be diluted are ejected are provided on the gas flow downstream side and the side surface facing the inner wall surface of the mixer body 1. Also, it is different from the prior art in that they are arranged alternately on the side of the mixer body 1 facing the inner wall surface. For this reason, it is easy to secure the number and size of the dispersion holes 3, the gas dispersibility in one dilution gas supply pipe 2 is improved, and it is possible to cope with the condition where the ratio of the dilution gas to the mainstream gas becomes high. It becomes like this.

  Further, the dilution gas supply pipe 3 has a straight pipe shape, and the dispersion hole can be easily cleaned by pulling out the dilution gas supply pipe 2 from the duct when the apparatus is stopped. Further, since the dispersion hole 3 of the diluted gas supply pipe is not provided in the flow direction of the mainstream gas, solid matter contained in the mainstream gas is less likely to enter the dispersion hole 3 and is excellent in maintainability. .

  The mixing plate 5 is composed of shielding blades, and has a structure that positively generates vortices on the downstream side of the shielding blades without giving a swirling action to the mainstream gas flow flowing in the gas mixer body 1. Therefore, the gas mixing property on the downstream side of the mixing plate 5 is improved.

  Further, when the diluted gas supply pipe 2 and the mixing plate 5 are viewed from the downstream side of the mixer body 1, the dispersion holes 3 and the shielding blade portions of the mixing plate 5 are shifted so as not to overlap except for the central portion thereof. Since it arrange | positions, the blow-off of the mainstream gas to the area | region where the dispersion | distribution hole 3 is not arrange | positioned is prevented, and mixing of mainstream gas and to-be-diluted gas is not inhibited.

  2 is a view of the inside of a gas mixer according to an embodiment of the present invention (FIG. 2 (a)) and a view taken along the line D-D as viewed from the downstream side of the gas flow in FIG. 2 (a). 2 (b)).

  In the embodiment shown in FIG. 2, two cross-shaped mixing plates 5 are placed apart from each other, and when viewed from the upstream side of the mixer body 1, the shielding blade portion between the mixing plates 5 excludes the central portion. 1 is different from FIG. 1 in that they are arranged so as not to overlap each other. The other configuration is the same as that of the first embodiment shown in FIG.

  By using a plurality of mixing plates 5, it is possible to obtain higher mixing characteristics of the mainstream gas and the gas to be diluted than in the first embodiment shown in FIG. 1, and the length of the mixer main body 1 can be shortened.

  In the above embodiment, the cross-shaped mixing plate 5 is used. However, the shape of the mixing plate 5 is not limited to this, and may be, for example, a single character.

  The present invention can be used as a gas mixer that can cope with a wide range of operating conditions, for example, as an ammonia gas injection device of an exhaust gas denitration device.

The figure (FIG. 1 (a)) which looked at the inside of the gas mixer of one Example of this invention, and the AA line, the BB line, and C--viewed from the downstream of the gas flow of FIG. 1 (a). It is each arrow line view (FIG.1 (b)-FIG.1 (d)) of C line | wire. The figure which looked at the inside of the gas mixer of one example of the present invention (Drawing 2 (a)) and the DD arrow line view (Drawing 2 (b)) seen from the downstream of the gas flow of Drawing 2 (a) )). It is the figure (FIG.3 (a)) which looked at the inside of the gas mixer of a prior art, and the AA arrow line view (FIG.3 (b)) seen from the downstream of the gas flow of Fig.3 (a). . The figure which looked at the inside of the gas mixer of a prior art (FIG. 4 (a)) and the AA arrow line view (FIG.4 (b)) B- from the downstream of the gas flow of Fig.4 (a) B- It is a B line arrow line view (Drawing 4 (c)). It is the figure (FIG.5 (a)) which looked at the inside of the gas mixer of a prior art, and the AA arrow line view (FIG.5 (b)) seen from the upstream of the gas flow of Fig.5 (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas mixer body 2 Diluted gas supply pipe 3 Dispersion hole 4 Mixer 5 Mixing plate 6 Ejection hole 7 Center hole 8 Column

Claims (5)

In a mixer that mixes both gases by supplying the gas to be diluted into the duct through which the main gas flows.
When viewed from the upstream side of the duct, the respective dilution gas supply pipes are shifted in the gas flow direction so that the two dilution gas supply pipes have a cross shape, and are inserted into the duct from the duct side surface. Dispersion holes for injecting dilution gas are provided on the downstream side and both side surfaces of the dilution gas supply pipe, and at least one mixing plate composed of cross-shaped shielding blades is installed on the downstream side of the dilution gas supply pipe. A gas mixer characterized by.   The gas mixer according to claim 1, wherein the dilution gas supply pipe has a straight pipe shape, and the dispersion holes are alternately arranged on the gas flow downstream side and the side surface side.   3. The gas mixer according to claim 1, wherein the mixing plate includes a flat shield blade that does not give a swirling action to a main gas flow and generates a vortex downstream of the shield blade. 4. .   When the dilution gas supply pipe and the mixing plate are viewed from the upstream side of the duct, the dilution gas supply pipe and the shielding blade portion of the mixing plate are arranged so as not to overlap except at the center. Item 4. A gas mixer according to any one of Items 1 to 3.   The two or more mixing plates are arranged so as to be shifted so that the shielding blade portions of adjacent mixing plates do not overlap except at the center when viewed from the upstream side of the duct. The gas mixer according to any one of 1 to 3.

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