JP3027701U - Ammonia gas injection device in denitration device - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To provide an ammonia gas injecting device capable of preventing deterioration of denitration performance in a denitration reactor by collecting a heat insulating material or the like coming from upstream at the time of injecting ammonia gas. . SOLUTION: The ammonia gas injection device is attached to three parallel support members 6, a plurality of parallel ammonia injection pipes 7 supported on their upper surfaces, and a lower surface side of the support member 6. It is composed of a circular filter 8 and a pressure gauge 10 for detecting the difference between the upstream pressure and the downstream pressure of the filter 8.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 This invention removes nitrogen oxides (NOx) in exhaust gas containing a large amount of solid matter such as combustion dust such as coal combustion exhaust gas, diesel engine exhaust gas, iron and steel sintering furnace exhaust gas, etc. by selective catalytic reduction. The present invention relates to a device for injecting an exhaust gas reducing agent, ammonia gas, in a denitration device.

[0002]

[Prior art]

 2. Description of the Related Art A denitration device including a denitration reactor and an ammonia gas injection device called an ammonia grid arranged upstream of the denitration reactor is conventionally known.

The ammonia gas injection device in this conventional denitration device has a plurality of ammonia injection pipes supported by a support, and the ammonia injection ports are provided at predetermined intervals in the length direction of each ammonia injection pipe. By being provided, a plurality of ammonia injection ports are arranged in a grid pattern as a whole, whereby the concentration distribution of ammonia gas is kept uniform. Then, the ammonia gas injecting device injects the vaporized ammonia gas into the exhaust gas in an amount equal to NOx in the exhaust gas, and reacts this with the catalyst in the denitration reactor placed downstream, so that NO x It is converted to ₂ and H ₂ O and rendered harmless.

[0004]

[Problems to be solved by the device]

 In the above-mentioned conventional denitration device, especially when the operation is started, the heat insulating material on the inner surface of the upstream flue scatters and adheres to the catalyst of the denitration reactor, increasing the pressure loss of the catalyst layer and improving the denitration performance. An accident of falling occurs. In the case of such an accident, the operation of the denitration equipment is stopped to clean the catalyst, but the cleaning work inside the reactor is troublesome and it is impossible to completely remove the deposits. there were.

The purpose of this invention is to prevent the deterioration of the denitration performance in the denitration reactor by collecting the heat insulating material or the like coming from the upstream in the denitration device at the time of injecting the ammonia gas in the denitration device. To provide a device.

[0006]

[Means for Solving the Problems]

 In the ammonia gas injection device in the denitration device according to the present invention, the ammonia injection pipes having the ammonia injection ports provided at a predetermined interval in the length direction are arranged in parallel, and are supported in parallel with each other. In the ammonia gas injecting device in the denitration equipment, which is supported by the material, the filter is detachably provided.

The ammonia gas injecting device in the denitration device according to the present invention can be obtained only by detachably attaching the filter to the existing parallel support material, which suppresses the increase of the equipment cost as much as possible, and further, the upstream of the denitration device. It is possible to collect foreign materials such as heat insulation materials that have come in from when the ammonia gas is injected.

The filter is a wire mesh with a negligible pressure loss, and its opening is such that the equivalent diameter of the cross section of the passage of the filter is 1/5 or more and 1/2 or less of the equivalent diameter of the cross section of the passage of the catalyst block. Is preferred.

A pressure gauge may be provided to detect the difference between the upstream pressure and the downstream pressure of the filter. In this way, the pressure difference becomes large, and the clogging of the filter can be confirmed.

[0010]

[Embodiment of device]

 An embodiment of the present invention will be described below with reference to the drawings. In the following description, the upper and lower sides mean the upper and lower sides of FIG.

FIG. 1 shows a denitration device (1) arranged in an exhaust heat recovery boiler. The denitration device (1) includes a denitration reactor (2) and an ammonia injection grid (ammonia injection device) upstream thereof. ) (3) and is installed inside the exhaust gas outlet duct (4) with a circular cross section of the boiler.

The denitration reactor (2) is provided with a plurality of catalyst blocks (5) filled with a plurality of catalysts having a large number of vertical independent passages.

As shown in FIGS. 1 to 3, the ammonia injection grid (3) includes three parallel support members (6) and a plurality of parallel ammonia injection pads supported on the upper surface side of these support members (6). Type (7), a circular filter (8) attached to the lower surface of the support (6), and a pressure gauge (10) that detects the difference between the upstream pressure and the downstream pressure of the filter (8). It consists of.

The filter (8) is a wire mesh with negligible pressure loss, and is provided with reinforcing members (9) arranged in a grid pattern. With respect to the openings of the filter (8), the equivalent diameter of the cross section of the passage of the filter (8) is preferably 1/5 or more and 1/2 or less of the equivalent diameter of the cross section of the passage of the catalyst block.

Each ammonia injection pipe (7) is provided with a large number of injection ports (11) at predetermined intervals in the lengthwise direction, and vaporized ammonia gas is exhausted from the ammonia injection grid (3) from NOx in the exhaust gas. By injecting the same amount into the exhaust gas and reacting it with the denitration catalyst in the denitration reactor (2) that is placed downstream by a distance sufficient to uniformly disperse in the exhaust gas, NOx becomes N ₂ It is converted to H ₂ O and rendered harmless.

A heat insulating material such as rock wool is provided on the inner surface of the duct (4) and the like, and the heat insulating material and the like may scatter especially at the start of operation. When foreign substances such as heat insulating materials adhere to the catalyst of the denitration reactor (2), the pressure loss in the catalyst layer increases, and the denitration performance deteriorates. The heat insulating material that has come in can be collected by the filter (8) of the ammonia injection grid (3), which prevents deterioration of the denitration performance of the denitration reactor (2).

One embodiment for attaching the filter (8) to the support (6) is shown in an enlarged scale in FIG. In the figure, a ring-shaped filter mounting frame (12) is provided on the periphery of the filter (8), and a support member (13) for supporting the filter mounting frame (12) is provided on the support member (6). Has been. The filter mounting frame (12) consists of a horizontal part (12a) whose inner edge is welded to the peripheral part of the filter (8) and a vertical part (12b) extending upward from the outer edge of the horizontal part (12a). . The support portion (13) includes an inner hanging portion (13a) and an outer hanging portion (13b). The vertical part (12b) of the filter mounting frame (12) is fitted between the inner hanging part (13a) and the outer hanging part (13b). Then, the tightening bolt (14) screwed from the outside into the screw hole formed in the outer hanging portion (13b) comes into contact with the vertical portion (12b) of the filter mounting frame (12), so that the support material ( The filter (8) is detachably attached to 6).

Another embodiment of attaching the filter (8) to the support (6) is shown in an enlarged scale in FIG. In the figure, a ring-shaped filter mounting frame (15) is provided on the periphery of the filter (8), and a bolt (16) for supporting the filter mounting frame (15) is welded to the support material (6). Has been done. The filter mounting frame (15) has a lower horizontal part (15a) whose inner edge is welded to the peripheral part of the filter (8), an upper horizontal part (15b) having a bolt insertion hole, and both horizontal parts (15a). ) (15b) is connected to the vertical part (15c). Then, the tightening nut (17) is fitted to the bolt (16) inserted into the bolt insertion hole of the upper horizontal portion (15b) of the filter mounting frame (15), and the filter (6) is attached to the support member (6). 8) is detachably attached.

The form in which the filter (8) is detachably attached to the support material (6) is not limited to the one shown in FIGS. 4 and 5. In the ammonia injection grid (3), the pressure difference indicated by the pressure gauge (10) becomes large, so that the clogging state of the filter (8) can be confirmed, so that the occurrence of abnormality can be detected early. In such a case, it suffices to take out the filter (8) and wash it, which can suppress an increase in equipment cost as much as possible and can also reduce the time and effort for cleaning.

[0020]

[Effect of device]

 According to the ammonia gas injection device in the denitration device of the present invention, the increase in equipment cost can be suppressed as much as possible, and moreover, the foreign matter such as the heat insulating material flying from the upstream of the denitration device can be collected at the time of ammonia gas injection. As a result, it is possible to prevent deterioration of the denitration performance in the denitration reactor installed downstream.

In the case where the pressure gauge for detecting the difference between the upstream pressure and the downstream pressure of the filter is provided, the clogging state of the filter can be confirmed by the increase of the pressure difference, and the occurrence of abnormality can be promptly detected. Can be detected.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the entire denitration apparatus.

FIG. 2 is a bottom view showing an ammonia gas injection device in the denitration device according to the present invention.

FIG. 3 is a vertical cross-sectional view showing an ammonia gas injection device in a denitration device according to the present invention.

FIG. 4 is an enlarged vertical sectional view of a filter mounting portion in FIG.

FIG. 5 is an enlarged vertical sectional view showing another embodiment of the filter mounting portion.

[Explanation of symbols]

(1) Denitration device (3) Ammonia injection grid (ammonia injection device) (6) Support material (7) Ammonia injection pipe (8) Filter (10) Pressure gauge (11) Ammonia injection port

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01D 53/94 B01D 53/36 ZAB 101 A (72) Inventor Nobuo Matsumoto Nishikujo 5 5 Konohana-ku, Osaka City 3-28, Hitachi Shipbuilding Co., Ltd. (72) Tadayuki Aoki 5-28-3, Nishikujo, Konohana-ku, Osaka City Hitachi Shipbuilding Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. An ammonia injection pipe having an ammonia injection port (11) provided at a predetermined interval in the length direction.
In the ammonia gas injection device in the denitrification device, the filter (8) is detachably provided in such a manner that (7) are arranged in parallel and are supported by the parallel support material (6) orthogonal to these. An ammonia gas injecting device in a denitration device, which is characterized in that 2. The ammonia gas injection device in the denitration device according to claim 1, further comprising a pressure gauge (10) for detecting a difference between the upstream pressure and the downstream pressure of the filter (8). .