Ammonia spray nozzle and ammonia spray unit

Abstract

The utility model relates to the field of environmental protection, and discloses an ammonia spray nozzle, including an output pipe and a conical head; the tip of the conical head extends to the inside of the output pipe, and a gap is left between the conical head and the output pipe; the conical head and the output pipe are connected by a connector; the diameter of the thick end of the conical head is larger than the outer diameter of the output pipe. The nozzle has a simple structure, and a gap is formed between the conical body and the input pipe. It can fully mix the air-ammonia mixed gas with the high-temperature airflow along the high-temperature airflow, and the conical head prevents smoke from accumulating in the output pipe. At the same time, the utility model also discloses an ammonia spray unit.

Description

Technical Field

[0001] The utility model relates to the technical field of environmental protection equipment, in particular to an ammonia spray nozzle and an ammonia spray unit. Background Art

[0002] CN112403264A discloses an ammonia spraying grid for an SCR denitration system. Adjacent branch pipe assemblies on the ammonia spraying grid are arranged in a cross-staggered manner. The branch pipe assemblies on the same ammonia spraying grid are arranged in a layered manner with a high middle and low surroundings according to the characteristics of flue gas on the same cross section having a high flow velocity in the middle and a low flow velocity in the surroundings. This is beneficial to expanding the effective area of ​​ammonia spraying and making the ammonia react more evenly with NOx in the flue gas. A sharp upper cone is provided on the nozzle of the branch pipe assembly, which can effectively break up the large dust blocks collapsed on the upper side, and the smooth outer surface design of the upper cone makes it difficult for dust to deposit. The lower cone is provided with transverse blades and longitudinal blades, which change the ammonia flow from vertically upward to oblique rotation and diffusion at a certain angle, thereby strengthening the reaction between ammonia and NOx in the flue gas. X Mixed effect.

[0003] The nozzle adopts a sharp upper cone and blades, and its structure is complex. Utility Model Content

[0004] The purpose of the utility model is to solve the above-mentioned problem and provide an ammonia spray nozzle, which has a simple structure and a gap between the cone and the input pipe. It can fully mix the air-ammonia mixed gas with the high-temperature airflow along the high-temperature airflow, and the cone head avoids the accumulation of smoke and dust in the output pipe.

[0005] Meanwhile, the utility model also discloses an ammonia spraying unit.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] An ammonia spray nozzle comprises an output pipe and a conical head; the tip of the conical head extends into the interior of the output pipe, and a gap is left between the conical head and the output pipe; the conical head and the output pipe are connected by a connecting piece; the diameter of the thick end of the conical head is larger than the outer diameter of the output pipe.

[0008] At the same time, the utility model also discloses an ammonia injection unit, comprising a plurality of partitions arranged in a channel on the inlet side of an external SCR catalytic unit, wherein the partitions divide the channel on the inlet side of the external SCR catalytic unit into a plurality of subdivided channels; a plurality of ammonia injection nozzles as described above are arranged in each subdivided channel; the output pipe of each ammonia injection nozzle is connected to the input pipe; and the input pipe is connected to an external ammonia-air mixing unit.

[0009] Compared with the prior art, the beneficial effects of the utility model are:

[0010] The utility model adopts a conical head, which is extended to the inside of the output pipe, so that the gap formed in the output pipe is gradually reduced, and the air-ammonia mixed gas is gradually accelerated at this stage. After leaving the output pipe, it is mixed with the high-temperature airflow on the outer wall of the conical head to form a mixed airflow, which not only does not cause dust blockage, but also can improve the mixing uniformity of the high-temperature airflow and the ammonia gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a stereogram of Example 1;

[0012] Figure 2 is an axial cross-sectional view of Example 1;

[0013] Figure 3 is an application schematic diagram of Example 1;

[0014] Figure 4 is a front view of Example 2;

[0015] Figure 5 Example 2 Figure 4 EE cross-sectional view;

[0016] Figure 6 This is a layout diagram of the ammonia spray nozzles in the subdivided channels of Example 2. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] Example 1

[0019] refer to Figures 1 to 3 An ammonia spray nozzle comprises an output pipe 1 and a conical head 2; the tip of the conical head 2 extends into the interior of the output pipe 1, and a gap 3 is left between the conical head 2 and the output pipe 1; the conical head 2 and the output pipe 1 are connected by a connecting piece; the diameter of the thick end of the conical head 2 is larger than the outer diameter of the output pipe 1.

[0020] There are two key design points in this embodiment: 1. The conical head 2 extends into the interior of the output pipe 1 to form a gradually narrowing gap 3; 2. The thick section of the conical head 2 is relatively thick, which enables the air-ammonia mixture to be mixed with the high-temperature flue gas at a high speed on the periphery of the cone, and the mixing effect is good.

[0021] In practical applications, the flue gas flows from the tip of the conical head 2 to the thick end, and the air-ammonia mixed gas is mixed with the high-temperature flue gas at the end of the output pipe 1 and flows along the outer wall of the conical head 2. The air-ammonia mixed gas is provided by an external ammonia-air mixing unit, which mixes ammonia and heated air and then inputs them into the output pipe 1.

[0022] Preferably, the connecting member is a connecting plate 4; there are multiple connecting plates 4; the connecting plates 4 extend to the edge of the conical head 2; and adjacent connecting plates 4 form a gas flow channel.

[0023] In this embodiment, the connecting plate 4 is made into a component constituting the gas flow channel, which divides the outer wall of the conical head 2 into a plurality of independent gas flow channels. The advantage of doing so is that the air-ammonia mixture of the output pipe 1 is divided into a plurality of equal parts. The plurality of air-ammonia mixtures can be fully mixed with the high-temperature flue gas in the independent gas flow channels and ejected outward along the side walls of the conical head 2. Compared with a structure without the connecting plate 4 or a structure in which the connecting plate 4 is not sufficient to separate and form separate gas flow channels, the speed at which the gas is ejected is reduced.

[0024] Preferably, the other end of the connecting plate 4 is fixedly connected to the outer side wall of the output pipe 1, and the outer edge of the connecting plate 4 and the edge of the thick end of the cone are located on the same plane.

[0025] Through this optimization, the air-ammonia mixture and high-temperature flue gas are actually controlled to be stably guided to the edge of the thick end of the conical head 2 in the gas flow channel. Before leaving the conical head 2, the gases in the adjacent gas flow channels will not be pre-mixed, which will make the ejection speed of the air flow faster when leaving the conical head 2. From a macroscopic perspective, it is more conducive to the mixing of the air-ammonia mixture and high-temperature flue gas.

[0026] More specifically, the connecting plates 4 are four pieces, and are evenly distributed outside the cone.

[0027] As a preferred embodiment of this embodiment, the cross-section of the conical head 2 is an equilateral triangle, the width of the narrowest part of the gap 3 is 7.3 mm; the width of the connecting plate 4 is 9.2 mm; the outer diameter of the output pipe 1 is 32 mm, the inner diameter is 26 mm, and the depth of the conical head penetrating into the output pipe is 9.8 mm.

[0028] The design of this specification is applied to a 350MW domestic extraction steam heating air-cooled unit and applied to an SCR catalytic unit. The specific application scenario can refer to Example 2 to test the CV deviation A of the ammonia nitrogen molar ratio distribution in each partition of the catalyst inlet flue section and the average relative standard CV deviation B of the velocity distribution of the first layer catalyst inlet section under full load conditions;

[0029] The CV deviation A of the ammonia nitrogen molar ratio distribution is 1.31%, and the average relative standard CV deviation B of the velocity distribution is 5.6%, which meets the design requirement of the CV deviation of the ammonia nitrogen molar ratio distribution in each partition of the catalyst inlet flue section <2.5%. The average relative standard deviation CV of the velocity distribution of the first layer catalyst inlet section is <10%.

[0030] Example 2

[0031] refer to Figures 4 to 6 An ammonia injection unit includes a plurality of partitions 6 arranged in a channel 5 on the inlet side of an external SCR catalytic unit, wherein the partitions 6 divide the channel on the inlet side of the external SCR catalytic unit into a plurality of subdivided channels 7; each subdivided channel 7 is provided with a plurality of ammonia injection nozzles as described in Example 1; the output pipe of each ammonia injection nozzle is connected to an input pipe 8; the input pipe 8 is connected to an external ammonia-air mixing unit. Nine ammonia injection nozzles are arranged in the subdivided channel 7 in a 3*3 form, wherein the most central ammonia injection nozzle extends to a position of 1.2-1.4m in the subdivided channel 7, and the remaining ammonia injection nozzles extend to a position of 0.4-0.6m in the subdivided channel 7.

[0032] Each subdivided channel 7 is isolated from each other when spraying ammonia, which can avoid the influence between adjacent subdivided channels 7. Dividing into multiple subdivided channels 7 does not increase the smoke resistance. At the same time, it can ensure the uniformity of the mixing of smoke and ammonia in each channel.

[0033] Preferably, the cross-sectional specification of the channel at the inlet side of the SCR catalytic unit is 2.9m×7.5m, and the number of the subdivided channels 7 is 6, which are arranged in two rows, and the specification of each subdivided channel 7 is 1.45m*2.5m.

[0034] Each of the central ammonia spray nozzles extends to a position of about 1.3 m in the subdivided channel 7; the remaining ammonia spray nozzles extend to a position of about 0.5 m in the subdivided channel 7 and maintain a distance of 0.36 m from the inner wall of the subdivided channel 7.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements or modifications without departing from the principle of the present invention. These improvements or modifications should also be regarded as within the protection scope of the present invention.

Claims

1. An ammonia spray nozzle, comprising an output pipe, characterized in that: It also includes a conical head; the tip of the conical head extends to the inside of the output tube, and a gap is left between the conical head and the output tube; the conical head and the output tube are connected by a connecting piece; the diameter of the thick end of the conical head is larger than the outer diameter of the output tube.

2. The ammonia spray nozzle according to claim 1, characterized in that: The connecting piece is a connecting plate; there are multiple connecting plates; the connecting plate extends to the edge of the conical head; and adjacent connecting plates form a gas flow channel.

3. The ammonia spray nozzle according to claim 2, characterized in that: The other end of the connecting plate is fixedly connected to the outer side wall of the output pipe.

4. The ammonia spray nozzle according to claim 2, characterized in that: The outer edge of the connecting plate and the edge of the thick end of the cone are located on the same plane.

5. The ammonia spray nozzle according to claim 2, characterized in that: There are four connecting plates, which are evenly distributed outside the cone.

6. The ammonia spray nozzle according to claim 1, characterized in that: The cross section of the conical head is an equilateral triangle.

7. The ammonia spray nozzle according to claim 4, characterized in that: The width of the gap is 7.3 mm; the width of the connecting plate is 9.2 mm; and the outer diameter of the output pipe is 32 mm.

8. An ammonia injection unit, characterized in that: The invention comprises a plurality of partitions arranged in a channel on the inlet side of an external SCR catalytic unit, wherein the partitions divide the channel on the inlet side of the external SCR catalytic unit into a plurality of subdivided channels; each subdivided channel is provided with a plurality of ammonia spray nozzles according to any one of claims 1 to 7; The output pipe of each ammonia spray nozzle is connected to the input pipe; the input pipe is connected to an external ammonia-air mixing unit.

9. The ammonia injection unit according to claim 8, characterized in that: Nine ammonia spray nozzles are arranged in the subdivided channel; the nine ammonia spray nozzles are arranged in a 3*3 form, wherein the central ammonia spray nozzle extends to a position of 1.2-1.4m in the subdivided channel, and the remaining ammonia spray nozzles extend to a position of 0.4-0.6m in the subdivided channel.

10. The ammonia injection unit according to claim 8, characterized in that: The number of the subdivided channels is 6, which are arranged in two rows, and the specification of each subdivided channel is 1.45m*2.5m.

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