Ammonia spraying grid low speed swirl hood and ammonia spraying grid

Abstract

The present invention discloses a low-speed swirl hood for an ammonia spraying grid and an ammonia spraying grid. The low-speed swirl hood for an ammonia spraying grid is located above the nozzle of the ammonia spraying grid, and includes a cap body, the cap body has a bottom cone surface that is larger at the top and smaller at the bottom, and the bottom cone surface is provided with a plurality of spiral airflow guiding structures extending from the middle of the bottom cone surface; a support frame connects the cap body and the ammonia spraying grid, and a gap is left between the bottom cone surface of the cap body and the top of the nozzle. By setting a cone body, the ammonia flow is changed from vertically upward to diagonally diffused at a certain angle, which can reduce the vertical flow velocity of the ammonia flow to a certain extent, and the ammonia flow is guided by a spiral boss to rotate and rise, further reducing the vertical flow velocity of the ammonia flow, thereby increasing the mixing time of the ammonia flow and the flue gas, and the rotating ammonia flow is conducive to improving the mixing efficiency with the flue gas; in addition, the cap body is located above the nozzle, which can effectively prevent ash accumulation from falling into the nozzle and causing blockage, and is safe and reliable.

Description

Technical Field

[0001] The invention relates to the field of denitration equipment, and in particular to an ammonia spraying grid low-speed swirl hood and an ammonia spraying grid. Background Art

[0002] SCR is a flue gas denitrification technology that has been widely used and developed rapidly in recent years. SCR denitrification systems are also commonly found in large thermal power plants. In SCR denitrification systems, ammonia injection grids are generally installed. The design of ammonia injection grids divides the flue cross section into several control areas, each of which has several injection holes. The ammonia injection grid includes an ammonia injection pipeline, a support device, accessories, and an ammonia distribution device, among which the nozzle on the ammonia injection pipeline is the core component.

[0003] However, the current nozzle structure usually has the following problem, that is, the nozzle wind speed is too high. At present, the nozzle wind speed of the ammonia spray grid is generally designed to be 20m / s. As the emission indicators become increasingly stringent, the actual ammonia spraying amount of each plant is generally greater than the design level. If some nozzles are blocked, the ammonia consumption has not decreased, so the working nozzle wind speed will increase. According to statistics, the nozzle wind speed of the ammonia spray grid in each plant generally reaches 20m / s to 40m / s. The higher wind speed reduces the mixing time of ammonia and flue gas. Compared with the flue gas wind speed, ammonia is more rigid, which affects the mixing effect of ammonia and flue gas. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes an ammonia spray grid low-speed swirl hood and an ammonia spray grid, which can change the direction of the sprayed ammonia flow, effectively reduce the vertical flow velocity of the ammonia flow, and thus increase the mixing effect of the ammonia flow and the flue gas.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] In a first aspect, a low-speed swirl hood for an ammonia spray grid is located above a nozzle of the ammonia spray grid, and comprises a hood body, wherein the hood body has a bottom conical surface that is larger at the top and smaller at the bottom, and the bottom conical surface is provided with a plurality of spiral airflow guiding structures extending from the middle of the bottom conical surface to guide the direction of the ammonia airflow;

[0007] A support frame connects the cap body and the ammonia spray grid and leaves a gap between the bottom conical surface of the cap body and the top of the nozzle.

[0008] The low-speed swirl hood of the ammonia spray grid according to the embodiment of the first aspect of the present invention has at least the following technical effects: by setting the bottom cone surface, the ammonia flow is changed from vertically upward to diagonally diffused at a certain angle, which can reduce the vertical flow velocity of the ammonia flow to a certain extent, and the ammonia flow is guided by the airflow guiding structure to make the ammonia flow rotate and rise, further reducing the vertical flow velocity of the ammonia flow, thereby increasing the mixing time of the ammonia flow and the flue gas, and the rotating ammonia flow is beneficial to improving the mixing efficiency with the flue gas; in addition, the cap body is located above the nozzle, which can effectively prevent ash accumulation from falling into the nozzle and causing blockage, which is safe and reliable.

[0009] In combination with the first aspect, in some implementations of the first aspect, the airflow guiding structure includes a spiral boss.

[0010] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the plurality of spiral bosses are evenly distributed on the bottom conical surface of the cap body.

[0011] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the cap body is in the shape of a cone that is larger at the top and smaller at the bottom, and the outer peripheral surface of the cap body forms the bottom cone surface.

[0012] In combination with the first aspect and the above-mentioned implementations, in some implementations of the first aspect, the connection position between the support frame and the cap body avoids the bottom conical surface of the cap body.

[0013] In a second aspect, an ammonia injection grid comprises a grid body and an ammonia injection grid low-speed swirl hood in any implementation of the first aspect, wherein the grid body has an ammonia injection branch pipe, and a nozzle is provided on the ammonia injection branch pipe.

[0014] The ammonia spray grid according to the embodiment of the second aspect of the present invention has at least the following technical effects: by adopting the above-mentioned ammonia spray grid low-speed swirl hood, on the one hand, the possibility of nozzle clogging is effectively reduced, thereby reducing the frequency of cleaning and maintenance of the equipment and extending the service life of the equipment; on the other hand, the mixing effect of the ammonia flow and the flue gas is enhanced, thereby enhancing the denitrification effect of the equipment.

[0015] In combination with the second aspect, in certain implementations of the second aspect, the axis of the cap body coincides with the axis of the nozzle, and the outer diameter of the top surface of the cap body is greater than the inner diameter of the nozzle.

[0016] In combination with the second aspect and the above-mentioned implementations, in certain implementations of the second aspect, a horizontal projection of the cap body is within a horizontal longitudinal cross-section of the ammonia injection branch pipe.

[0017] In combination with the second aspect and the above-mentioned implementation methods, in certain implementation methods of the second aspect, the spiral direction of the airflow guiding structure of the cap body includes a left-handed direction and a right-handed direction, and a plurality of the nozzles are arranged above the ammonia injection branch pipe, and the spiral directions of the airflow guiding structures of adjacent cap bodies of the same ammonia injection branch pipe are different.

[0018] In combination with the second aspect and the above-mentioned implementations, in certain implementations of the second aspect, the grille body includes a plurality of the ammonia injection branch pipes arranged in parallel, and the airflow guiding structures of the cap bodies aligned with each other on adjacent ammonia injection branch pipes have different spiral directions.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0021] Figure 1 It is a structural schematic diagram of an embodiment of the first aspect of the present invention (without the support frame);

[0022] Figure 2 This is a schematic diagram of an embodiment of the first aspect of the present invention connected to an ammonia injection grid;

[0023] Figure 3 It is a schematic structural diagram of a nozzle according to an embodiment of the second aspect of the present invention;

[0024] Figure 4 A schematic diagram of the structure of a partial ammonia injection grid according to an embodiment of the second aspect of the present invention;

[0025] Figure 5 This is a simulation diagram of the effect of mixing the ammonia flow sprayed out and the flue gas in the second embodiment of the present invention;

[0026] Figure 6 This is a simulation diagram of the concentration gradient after the ammonia flow sprayed out and the flue gas are mixed in the second embodiment of the present invention. DETAILED DESCRIPTION

[0027] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0028] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "inside", "outside", "top", "bottom", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0029] In the description of the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" etc. are understood to not include the number; "above", "below", "within" etc. are understood to include the number.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "provided with", "provided on", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] Reference below Figures 1 to 6 The invention describes an ammonia injection grid low-speed swirl hood and an ammonia injection grid having the same according to an embodiment of the present invention.

[0032] The low-speed swirl hood of the ammonia spray grid according to the embodiment of the first aspect of the present invention is located above the nozzle of the ammonia spray grid, and includes a cap body 100 and a support frame 200. The cap body 100 has a bottom conical surface that is larger at the top and smaller at the bottom, and a plurality of spiral airflow guiding structures extending from the middle of the bottom conical surface are provided on the bottom conical surface to guide the direction of the ammonia airflow; the support frame 200 connects the cap body 100 and the ammonia spray grid, and leaves a gap between the bottom conical surface of the cap body 100 and the top of the nozzle.

[0033] like Figure 1 and Figure 2 As shown, the bottom end face of the cap body 100 is conical to reduce the resistance of the ammonia gas flow; the bottom conical surface of the cap body 100 is provided with a plurality of spiral bosses 110, which extend from the middle of the bottom conical surface of the cap body 100 to the edge of the cap body 100 and are spiral-shaped, and a plurality of airflow guiding structures are evenly distributed around the axis of the cap body 100 and do not interfere with each other; the support frame 200 connects the cap body 100 and the nozzle. It can be imagined that the number of airflow guiding structures and the number of support frames 200 can be set to two or more according to the size of the cap body 100, the structure of the nozzle and the actual flow rate of the ammonia gas flow.

[0034] like Figure 5As shown, by providing a cap body 100 with a conical bottom, the ammonia flow is changed from vertically upward to diagonally diffused along the cone at a certain angle, and the ammonia flow is guided by the airflow guiding structure, changing the direction of the ammonia flow after it is ejected from the nozzle, so that the ammonia flow rotates and rises, effectively reducing the vertical flow velocity of the ammonia flow, thereby increasing the mixing time of the ammonia flow and the flue gas. In addition, the rotating ammonia flow meets the flue gas, effectively improving the mixing efficiency of the two. Figure 2 As shown, the cap body is located above the nozzle, which can effectively prevent dust from falling into the nozzle and causing blockage, thereby increasing the reliability of the equipment, which is simple and practical.

[0035] The airflow guiding structure may be a boss or a guide groove or a combination of a boss and a guide groove. Figure 1 In the illustrated embodiment, the airflow guiding structure includes a spiral boss 110, which extends radially along the bottom conical surface of the cap body 100. It is understandable that the spiral boss 110 can be perpendicular to the bottom conical surface or inclined to the bottom conical surface.

[0036] In some embodiments of the present invention, a plurality of spiral bosses 110 are evenly distributed on the outer circumference of the cap body 100. Through this arrangement, the spiral bosses 110 can guide the ammonia flow more evenly and effectively.

[0037] In some embodiments of the present invention, the cap body 100 is a cone-shaped body that is larger at the top and smaller at the bottom. The cap body 100 adopts a solid or shell-shaped structure, and the outer peripheral surface of the cap body 100 forms a bottom cone surface. Through this arrangement, the structure of the cap body 100 is lighter, reducing costs and molding difficulty.

[0038] In some embodiments of the present invention, the connection position between the support frame 200 and the cap body 100 avoids the bottom conical surface of the cap body 100, for example, Figure 1 In the illustrated embodiment, there are three support frames 200 which are evenly distributed around the nozzle axis. The support frames 200 connect the top surface of the cap body 100 and the upper portion of the nozzle to avoid the bottom conical surface and the airflow guiding structure to avoid adverse effects on the drainage of the ammonia flow.

[0039] The ammonia injection grid according to the second embodiment of the present invention comprises a grid body 300 and the ammonia injection grid low-speed swirl hood of the first embodiment, the grid body 300 has an ammonia injection branch pipe 310, and the ammonia injection branch pipe 310 is provided with a nozzle 311.

[0040] like Figure 4 As shown, an ammonia spray branch pipe 310 is provided above the grille body 300, and a plurality of nozzles 311 are evenly arranged on the ammonia spray branch pipe 310. It is conceivable that the number of nozzles 311 on the ammonia spray branch pipe 310 and the number of ammonia spray branch pipes 310 on the grille body 300 are set according to the flue gas flow required to be processed.

[0041] like Figure 6 As shown, by adopting the above-mentioned low-speed swirl hood of the ammonia spray grid, the concentration gradient of the ammonia flow and the flue gas after mixing is evenly distributed, that is, the ammonia flow and the flue gas are effectively mixed to achieve a better ammonia denitrification process.

[0042] In some embodiments of the present invention, the axis of the cap body 100 coincides with the axis of the nozzle 311 , and the outer diameter of the top surface of the cap body 100 is greater than the inner diameter of the nozzle 311 .

[0043] like Figure 2 As shown, by setting the axis of the cap body 100 to coincide with the axis of the nozzle 311, the cap body 100 can better guide the ammonia flow and reduce the resistance to the ammonia flow; at the same time, the outer diameter of the top surface of the cap body 100 is larger than the inner diameter of the nozzle 311, that is, the top of the nozzle 311 is completely blocked by the cap body 100, thereby effectively preventing dust from falling into the nozzle 311.

[0044] In some embodiments of the present invention, the horizontal projection of the cap body 100 is within the horizontal longitudinal section of the ammonia injection branch pipe 310 .

[0045] like Figure 2 and Figure 3 As shown, the nozzle 311 extends vertically upward along the axis of the ammonia injection branch pipe 310, and the axis of the cap body 100 coincides with the axis of the nozzle 311, that is, the axis of the cap body 100 also intersects with the axis of the ammonia injection branch pipe 310; the outer diameter of the ammonia injection branch pipe 310 is larger than the outer diameter of the top surface of the cap body 100, so that the horizontal projection of the cap body 100 completely falls within the horizontal longitudinal section of the ammonia injection branch pipe 310. With respect to the flow direction of the flue gas from bottom to top, the cap body 100 is completely blocked by the ammonia injection branch pipe 310, which, on the one hand, avoids increasing the resistance encountered by the flue gas when it rises, and on the other hand, avoids the flue gas hitting the cap body 100 and causing the possibility of ash accumulation falling into the nozzle 311.

[0046] In some embodiments of the present invention, the spiral direction of the airflow guide structure of the cap body 100 includes a left-handed direction and a right-handed direction, and a plurality of nozzles 311 are arranged above the ammonia injection branch pipe 310, and the spiral directions of the airflow guide structures of adjacent cap bodies 100 of the same ammonia injection branch pipe 310 are different. By staggering the cap bodies 100 with the left-handed airflow guide structure and the cap bodies 100 with the right-handed airflow guide structure, the collision between the ammonia flows sprayed from different nozzles 311 of the same ammonia injection branch pipe 310 and between the ammonia flow and the flue gas is made more frequent, so that the mixing is more complete and faster, and the ammonia denitrification effect of the equipment is enhanced.

[0047] In some embodiments of the present invention, the grille body 300 includes a plurality of ammonia injection branch pipes 310 arranged in parallel, and the airflow guide structures of the cap bodies 100 aligned with each other on adjacent ammonia injection branch pipes 310 have different spiral directions. Specifically, the grille body 300 is provided with a plurality of ammonia injection branch pipes 310 in parallel, and the nozzles on each ammonia injection branch pipe 310 are aligned one by one, and the cap bodies 100 aligned with each other on adjacent ammonia injection branch pipes 310 are provided with airflow guide structures with different spiral directions, that is, the collision between the ammonia flow sprayed by the nozzles 311 on different ammonia injection branch pipes 310 and between the ammonia flow and the flue gas is made more frequent, so that the mixing is more complete and faster, and the ammonia denitrification effect of the equipment is enhanced.

[0048] In the description of this specification, the description with reference to the terms "example", "embodiment" or "some embodiments" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0049] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A low-speed swirl hood for an ammonia spray grid, located above the nozzle of the ammonia spray grid, characterized in that: include: A cap body (100), the cap body (100) having a bottom conical surface that is larger at the top and smaller at the bottom, the bottom conical surface being provided with a plurality of spiral airflow guiding structures extending from the middle of the bottom conical surface, for guiding the direction of the ammonia airflow; A support frame (200), wherein the support frame (200) connects the cap body (100) and the ammonia spray grid and leaves a gap between the bottom conical surface of the cap body (100) and the top of the nozzle; The airflow guiding structure comprises a spiral boss (110); the cap body (100) is a cone-shaped body that is larger at the top and smaller at the bottom; the outer peripheral surface of the cap body (100) forms the bottom cone surface; and a plurality of spiral bosses (110) are evenly distributed on the bottom cone surface of the cap body (100).

2. The low-speed swirl hood for ammonia spray grid according to claim 1, characterized in that: The connection position between the support frame (200) and the cap body (100) avoids the bottom conical surface of the cap body (100).

3. An ammonia injection grid, characterized in that: include: A grille body (300) and an ammonia spraying grille low-speed swirl hood as claimed in any one of claims 1 to 2, wherein the grille body (300) has an ammonia spraying branch pipe (310), and a nozzle (311) is provided on the ammonia spraying branch pipe (310).

4. The ammonia injection grid according to claim 3, characterized in that: The axis of the cap body (100) coincides with the axis of the nozzle (311), and the outer diameter of the top surface of the cap body (100) is greater than the inner diameter of the nozzle (311).

5. The ammonia injection grid according to claim 3, characterized in that: The horizontal projection of the cap body (100) is within the horizontal longitudinal section of the ammonia injection branch pipe (310).

6. The ammonia injection grid according to claim 3, characterized in that: The spiral direction of the airflow guiding structure of the cap body (100) includes a left-hand direction and a right-hand direction, and a plurality of nozzles (311) are arranged above the ammonia injection branch pipe (310), and the spiral directions of the airflow guiding structures of adjacent cap bodies (100) of the same ammonia injection branch pipe (310) are different.

7. The ammonia injection grid according to claim 3, characterized in that: The grille body (300) comprises a plurality of ammonia injection branch pipes (310) arranged in parallel, and the airflow guide structures of the cap bodies (100) aligned with each other on adjacent ammonia injection branch pipes (310) have different spiral directions.

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