JP4959232B2 - Mixing accelerator for denitration apparatus and denitration apparatus having the same - Google Patents

Description

  The present invention relates to a denitration apparatus that reduces nitrogen oxides in exhaust gas while using ammonia or urea as a reducing agent. In particular, the present invention relates to a mixing accelerator for uniformly mixing the reducing agent into exhaust gas and a denitration apparatus including the mixing accelerator.

As disclosed in Patent Document 1 below, an exhaust gas duct to a catalyst denitration apparatus in an exhaust gas boiler facility, wherein an exhaust gas inlet and an outlet are arranged with a phase difference of approximately 90 °, and the exhaust gas at the outlet side There has been proposed an exhaust gas duct structure in which the drift of the catalyst is prevented and the catalyst efficiency is increased.
JP-A-8-327047

  However, in the conventional configuration, the exhaust gas may be distorted in the duct due to restrictions on the installation of the exhaust gas duct. Even if the exhaust gas velocity distribution is uniform, if there are restrictions on the spraying method, direction, and installation of the reducing agent, the reducing agent may not be uniformly mixed with the exhaust gas in the exhaust gas duct, which may cause bias. was there.

  The problem to be solved by the present invention is to provide a mixing accelerator capable of uniformly mixing the reducing agent into the exhaust gas, and to provide a denitration apparatus equipped with the mixing accelerator.

  The present invention has been made to solve the above-mentioned problems. The invention according to claim 1 is directed to a reducing agent injector for injecting a nitrogen oxide reducing agent into exhaust gas, and the reducing agent injector using the reducing agent injector. Is applied to a denitration reactor having a denitration catalyst having a denitration catalyst for reducing nitrogen oxides in the exhaust gas, and is provided in a flue for sending the exhaust gas to the denitration reactor. A mixing accelerator for a denitration apparatus, which is composed of an inclined material, a vertical material, or a porous material that mixes a reducing agent with exhaust gas.

  According to the first aspect of the present invention, the reducing agent can be uniformly mixed with the exhaust gas by using the inclined material, the vertical material, or the porous material.

  According to a second aspect of the present invention, upstream of the reducing agent injection portion into the flue by the reducing agent injector, the injection of the reducing agent from the inner wall of the flue is not hindered by the flow of exhaust gas. The mixing accelerator for a denitration apparatus according to claim 1, which is provided.

  According to the second aspect of the present invention, the reducing agent can be smoothly ejected from the inner wall of the flue, and the uneven flow of the reducing agent in the exhaust gas can be prevented.

  The invention according to claim 3 is provided downstream of the reducing agent jetting portion into the flue by the reducing agent injector, and the reducing agent jetted from the inner wall of the flue is caused by the flow of exhaust gas. The mixing accelerator for a denitration apparatus according to claim 1 or 2, wherein the mixing accelerator is provided to prevent movement along the inner wall of the flue.

  According to the third aspect of the present invention, it is possible to prevent uneven flow of the reducing agent ejected from the inner wall of the flue.

  The invention according to claim 4 is provided with a plate material covering about half of the flue on the side where the jet portion is provided, downstream of the jet portion, and a large number of openings penetrate through the plate material. The mixing accelerator for a denitration apparatus according to claim 3, wherein the mixing accelerator is formed.

  According to the fourth aspect of the present invention, the flow of the reducing agent ejected from the inner wall of the flue to the center in the radial direction of the flue can be corrected by the perforated plate.

  The invention according to claim 5 is provided with an inclined material provided on the inner wall on the side where the ejection portion is provided downstream from the ejection portion, and inclined so as to float from the inner wall as going downstream. The mixing accelerator for a denitration apparatus according to claim 3.

  According to the fifth aspect of the present invention, the drift of the reducing agent ejected from the inner wall of the flue can be corrected by the inclined material.

  The invention described in claim 6 is characterized in that angle steel is provided on the inner wall on the upstream side of the plate member or the inclined member and on the side where the ejection portion is provided. 5. A mixing accelerator for a denitration apparatus according to 5.

  According to invention of Claim 6, mixing of the reducing agent to exhaust gas can be further accelerated | stimulated with angle iron (L-shaped angle).

  Further, the invention described in claim 7 includes the reducing agent injector, the denitration reactor, and the mixing accelerator according to any one of claims 1 to 6. Device.

  According to the seventh aspect of the present invention, it is possible to provide a denitration apparatus that exhibits the operational effects of the first aspect of the present invention.

  According to the mixing accelerator for a denitration apparatus of the present invention and the denitration apparatus including the same, the reducing agent can be uniformly mixed into the exhaust gas by the mixing accelerator.

Next, an embodiment of a denitration apparatus according to the present invention will be described.
This denitration device is provided, for example, in the exhaust gas path from the combustion equipment provided in the generator. In addition, the denitration apparatus passes a reducing agent injector that injects a nitrogen oxide reducing agent into the exhaust gas, and an exhaust gas into which the reducing agent is injected by the reducing agent injector, and reduces the nitrogen oxide in the exhaust gas. And a denitration reactor loaded with a denitration catalyst. Then, a reducing agent is injected from the injector into the exhaust gas discharged from the combustion equipment, and this reducing agent reacts with NOx in the exhaust gas in the denitration reactor, and NOx is decomposed into nitrogen and water and rendered harmless. The As the reducing agent, for example, urea water, ammonia, ammonium bicarbonate and the like are preferably used. As the denitration catalyst loaded in the denitration reactor, for example, a vanadium or tungsten catalyst is preferably used. This denitration catalyst can promote the reaction between the reducing agent and NOx in the exhaust gas.

  As the reducing agent injector, for example, a stroke type pump is used, and a nozzle is attached to the discharge side tip of the pump, and the reducing agent is injected into the exhaust gas from the nozzle.

  And the mixing accelerator which mixes a reducing agent with waste gas uniformly is provided in the flue which sends the waste gas discharged | emitted from the said combustion apparatus to a denitration reactor. As the mixing accelerator, an inclined material, a vertical material, and a porous material are used.

  The mixing accelerator is provided either on the upstream side or the downstream side of the reducing agent jetting portion into the flue by the reducing agent injector. When provided on the upstream side of the jet part, a vertical material is used as a mixing accelerator, and this vertical material is provided upstream of the reducing agent jet part into the flue by the reducing agent injector. The flue is projected vertically from the inner wall side of the flue toward the radial center of the flue. In this way, the reducing agent ejected from the inner wall side of the flue toward the radial center of the flue can be smoothly ejected without being interrupted by the flow of the exhaust gas. The uneven flow of the reduced reducing agent is also prevented, and the reducing agent and the exhaust gas can be mixed uniformly.

  Further, the mixing accelerator can be provided downstream of the reducing agent jetting portion into the flue by the reducing agent injector, and in this case, a gradient material or a porous material is used as the mixing accelerator, It is provided so as to go from the inner wall side of the flue provided with the ejection portion toward the radial center of the flue. In this way, the reducing agent ejected from the inner wall side of the flue toward the center in the radial direction of the flue passes along the inner wall of the flue on the side where the ejection part is provided by the flow of exhaust gas. It is prevented from moving, and the flow of the jetted reducing agent is prevented.

  In the case of using an inclined material as the mixing accelerator, the inclined material is attached to the inner wall of the flue on the side where the ejection portion is provided on the downstream side of the ejection portion. Further, the inclined member floats from the inner wall as it goes downstream via a plurality of mounting legs, and is attached so that the rear side is directed to the center in the radial direction of the flue. In this way, the uneven flow of the reducing agent is corrected by the inclined material, and the reducing agent can be uniformly mixed into the exhaust gas. Further, the inclined material causes a vortex in the flow of exhaust gas in the flue, and the reducing agent ejected in the flue is diffused by this vortex, and uniform mixing of the reducing agent with the exhaust gas at a low pressure loss becomes possible.

  Further, as the mixing accelerator, a porous plate material having a large number of openings is used so as to cover the lower half in the flue on the side where the reducing agent jetting portion is provided, and this plate material is disposed downstream of the jetting portion. It may be arranged on the side. In this way, when the exhaust gas from which the reducing agent is ejected passes through the flue, the pressure loss in the lower half of the flue is high and flows upward of the plate material. At this time, the exhaust gas and the reducing agent are mixed and evenly mixed. Is achieved. The inclined material, the plate material, and the vertical material described above are installed at a position away from the ejection portion on the downstream side, for example, a position separated by about 1 m or more. This prevents the sprayed reducing agent from directly attaching.

Furthermore, angle steel is used as the mixing accelerator, and is provided along the radial center of the flue from the inner wall of the flue where the ejection portion is provided on the upstream side of the plate member or the inclined member. Also good. According to this configuration, when the exhaust gas passes through the angle steel, the exhaust gas is diverted by the both wall portions, and a vortex is generated at the rear, and the exhaust gas and the reducing agent are stirred and mixed by this vortex, and in this mixed state Since it reaches the plate member or the inclined member and is further mixed by them, the exhaust gas and the reducing agent are mixed more uniformly.
Example 1

  Hereinafter, a specific example of a denitration apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a control block diagram of a denitration apparatus according to the present invention. In the embodiment of this figure, a denitration reaction in which a generator 1 provided with a combustion device as a NOx emission source and a flue 2 extending from the generator 1 is connected and, for example, a vanadium-based denitration catalyst is loaded therein. The spray nozzle 41 which inject | pours, for example, urea water (reducing agent) which is arrange | positioned in the downstream of the generator 3 in the flue 2 and the generator 1 in the flue 2, and reduces NOx contained in this to the exhaust gas G which passes through the inside of the flue 2 is provided. A reducing agent injector 4 comprising a provided pump and a control means 5 for controlling the injection amount of the reducing agent R by the reducing agent injector 4 based on the power generation amount of the generator 1 are provided.

  The control means 5 detects the signal from the output unit 11 of the generator 1 and controls the injection amount from the injector 4 based on the injection amount of a function map determined in advance according to the power generation amount of the generator 1.

  FIG. 2 is a side view of the flue 2 provided with a mixing accelerator 6 for mixing the reducing agent R and the exhaust gas G injected from the injector 4, and FIG. 3 is a plan view thereof. In this figure, the flue 2 is formed by a plurality of circular pipes 21, 22 and is bolted to each other via pipe joints 23, 23 protruding from the outer circumferences of the pipes 21, 22. . Then, the nozzle 41 of the injector 4 is mounted upward at the lower position in the upstream portion of the first tube body 21 located on the upstream side in the flow direction of the exhaust gas G, and the second tube body on the downstream side of the nozzle 41. The mixing accelerator 6 according to the present invention is attached at a substantially intermediate position 22.

  4 is an enlarged side view showing the mixing accelerator 6, and FIG. 5 is a plan view thereof. In this embodiment, an inclined member 61 having a substantially triangular shape in plan view is used as the accelerator 6, and the inclined member 61 is attached to the second tubular body 22 on the downstream side of the nozzle 41 so that the corner portion is directed to the upstream side. Install. At this time, the inclined member 61 has a low level on the upstream side and a high level on the downstream side in the second tubular body 22 through the high and low mounting legs 62 and 63 attached to the front and rear positions of the back surface. It is attached to the lower part of the inner wall surface of the first tubular body 21 on the same side as the attachment side of the nozzle 41 so as to float upward from the inner wall surface.

  Furthermore, in the embodiment of this figure, the mixing accelerator 6 has an L-shaped angle at a position immediately downstream of the reducing agent jetting part F into the flue 2 by the nozzle 41 and immediately upstream of the inclined member 61. The angle steel 64 is attached so that the triangular corner is directed upstream. 6 is a side view of the angle steel 64, and FIG. 7 is a plan view thereof. The angle steel 64 is attached toward the radial center of the second tubular body 22 on the same side as the nozzle 41 attachment side on the inner wall of the second tubular body 22 at the front position of the inclined member 61.

According to the above configuration, the inclined member 61 is used as the mixing accelerator 6, and this inclined member 61 is located downstream of the nozzle 41 so that one corner thereof is directed upstream, and the second tubular body. 22 is attached to the same side of the nozzle 41 as the attachment side of the nozzle 41 so that it floats from the inner wall surface of the flue 2 as it goes downstream via a plurality of attachment legs 62, 63. The uneven flow of the reducing agent R in the ejected exhaust gas G is corrected, and uniform mixing of the reducing agent R into the exhaust gas G becomes possible. Further, since a vortex is generated behind the inclined member 61 in the flue 2, the reducing agent R ejected from the nozzle 41 toward the exhaust gas G is diffused by the vortex, and the low pressure loss of the reducing agent R with respect to the exhaust gas G is diffused. Uniform mixing is possible.
Example 2

  FIG. 8 is a front view showing still another embodiment of the mixing accelerator 6, and FIG. 9 is a side view thereof. The mixing accelerator 6 of this embodiment includes a circular plate-like plate member 65 sandwiched between the pipe joints 23 and 23 of the first and second pipe bodies 21 and 22 on the downstream side of the nozzle 41. The upper half of the plate material 65 is an open portion 66 from the center, and a large number of openings 68 are formed through a lower half plate portion 67 which is the lower half. Further, just in front of the plate member 65, an angle steel 64 similar to the L-shaped angle shown in FIGS. 3 and 4 is provided between the lower half plate portion 67 and the open portion 66 with the corner portion facing the upstream side. Attached across the. The outer periphery of the open portion 66 coincides with the inner periphery of the flue 2, and a large number of bolt holes 65 a are formed on the outer peripheral edge of the plate member 65 so as to be sandwiched between the pipe joints 23 and bolted. ing.

When the plate member 65 is provided on the downstream side of the nozzle 41 in the flue 2, the pressure loss on the lower half plate portion 67 side where many openings 68 of the plate member 65 are provided is high, and the pressure loss on the open portion 66 side of the plate member 65 is low. Therefore, the reducing agent R ejected from the nozzle 41 flows upward along with the exhaust gas G toward the open portion 66 side. As a result, the exhaust gas G and the reducing agent R are uniformly mixed when passing through the flue 2.
Example 3

  FIG. 10 is a side view of a flue 2 provided with still another embodiment of the mixing accelerator 6, and FIG. 11 is a plan view thereof. In this embodiment, an L-shaped vertical member 69 is used as the mixing accelerator 6, and the nozzle 41 is provided upstream of the vertical member 69 from the reducing agent jetting part F into the flue 2 by the nozzle 41. The flue is vertically projected from the inner wall side of the flue toward the radial center of the flue. In this way, the flow of the exhaust gas G is stopped or moderated in the portion behind the vertical member 69 provided inside the flue 2, and the reducing agent R is ejected upward along the back of the vertical member 69. Therefore, the reducing agent R is smoothly ejected to the vicinity of the center of the flue 2 without being immediately caused to flow downstream by the flow of the exhaust gas G, and the uneven flow of the ejected reducing agent R is prevented. Uniform mixing of the exhaust gas G in the flue 2 can be performed.

It is a piping block diagram which shows the Example of the denitration apparatus concerning this invention. It is a side view which shows the flue to which the mixing accelerator of this invention is applied. FIG. It is a side view which expands and shows the mixing accelerator of this invention. FIG. It is a side view which shows another Example of a mixing accelerator. FIG. It is a front view which shows another Example of a mixing accelerator. FIG. FIG. 6 is a side cross-sectional view of a flue with yet another mixing enhancer of the present invention. FIG.

Explanation of symbols

2 Flue 3 Denitration Reactor 4 Reducing Agent Injector 6 Mixing Promoter 61 Gradient Material 64 Angle Steel 65 Plate Material 68 Opening 69 Vertical Material G Exhaust Gas R Reducing Agent F Reducing Agent Injection Portion

Claims (5)

A reducing agent injector having a jetting part for jetting a reducing agent of a nitric acid compound from the inner wall of the flue to exhaust gas passing through the flue; and connected to the flue , and the reducing agent is injected by the reducing agent injector A denitration reactor having a denitration catalyst for reducing the nitrogen acid compound in the exhaust gas, and an inclined material for mixing the exhaust gas and the reducing agent are provided downstream of the jetting portion and upstream of the denitration reactor. A denitration device,
The inclined member has a triangular shape in plan view, and is attached to the inner wall on the side where the ejection portion is provided so that one corner portion of the triangular shape faces the upstream side. A mixing accelerator for a denitration apparatus, which is inclined so as to float upward from a wall surface . 2. The denitration according to claim 1 , wherein an angle steel is provided at a position immediately upstream of the inclined member toward a center in a radial direction of the flue so that a corner thereof is directed upstream. Mixing accelerator for equipment. A reducing agent injector having a jetting part for jetting a reducing agent of a nitric acid compound from the inner wall of the flue to exhaust gas passing through the flue; and connected to the flue, and the reducing agent is injected by the reducing agent injector A denitration reactor having a denitration catalyst for reducing the nitrogen acid compound in the exhaust gas, and a plate material for mixing the exhaust gas and the reducing agent downstream of the jetting portion and upstream of the denitration reactor. A denitration device provided to cover the lower half of the road,
The plate material has an upper half from the center as an open portion, and a plurality of openings are formed through the lower half plate portion, which is the lower half,
The outer periphery of the opening portion denitration mixing promotion vessel equipment characterized in that it coincides with the inner periphery of the flue. 4. The denitration apparatus according to claim 3, wherein the angle steel is attached between the lower half plate portion and the open portion so that the corner portion faces the upstream side immediately in front of the plate material . Mixing accelerator. The reductant injector, the denitration reactor, and the mixing accelerator according to any one of claims 1 to 4.
A denitration apparatus characterized by that.

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