An ammonia injection grid for SCR denitration system

Abstract

The present invention discloses an ammonia spraying grid of an SCR denitration system, comprising an ammonia spraying main pipe, an ammonia spraying branch pipe, a nozzle and a swirl mixer, wherein a plurality of ammonia spraying branch pipes are arranged on the ammonia spraying main pipe, and one end of the ammonia spraying branch pipe away from the ammonia spraying main pipe is arranged upward and connected to the nozzle, and the swirl mixer is fixed on the nozzle; the swirl mixer comprises a cylinder, a bracket and swirl blades, the cylinder is a hollow structure with upper and lower parts, the inner wall of the cylinder is connected to the nozzle through the bracket, and the inner wall of the cylinder above the bracket is fixed with a plurality of swirl blades in a circumferential array. The advantage of the present invention is that, through the arrangement of the swirl blades, after the flue gas in the SCR denitration system flows through the swirl blades, a strong rotational motion will be generated, which can entrain the ammonia sprayed from the upper nozzle of the ammonia spraying branch pipe, so that the ammonia and the flue gas are strongly mixed, the mixing effect of the flue gas and the ammonia is enhanced, and the denitration reaction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of denitration equipment, in particular to an ammonia injection grid of an SCR denitration system. Background Art

[0002] At present, the flue gas denitrification technologies that have been actually applied in power plants in my country mainly include selective catalytic reduction (SCR) technology, selective non-catalytic reduction (SNCR) technology and the combined technology of selective catalytic reduction-selective non-catalytic reduction. Among these three flue gas denitrification technologies, the selective catalytic reduction (SCR) technology is known as the mainstream technology for controlling nitrogen oxide emissions due to its advantages such as high denitrification rate and almost no secondary pollution.

[0003] At present, the SCR system mainly includes an ammonia storage and delivery system, an ammonia injection system, a reactor system, an ash removal system and a flue gas bypass. The design of the ammonia injection system is related to the mixing effect of ammonia and nitrogen oxides, and is a key factor in whether the SCR system can work effectively. The traditional ammonia injection system commonly uses a linear control type of ammonia injection grid. The linear control ammonia injection grid consists of a series of pipes with several nozzles arranged linearly on the flue cross section. The flow rate of each pipe can be adjusted individually to match the content of flue gas in each part. However, the mixing effect of flue gas and ammonia in the above linear control ammonia injection grid is not sufficient, resulting in low denitrification efficiency. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to improve the mixing effect of flue gas and ammonia and improve the denitrification efficiency.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] An ammonia injection grid of an SCR denitration system comprises an ammonia injection main pipe, an ammonia injection branch pipe, a nozzle and a swirl mixer. A plurality of ammonia injection branch pipes are arranged on the ammonia injection main pipe. One end of the ammonia injection branch pipe away from the ammonia injection main pipe is arranged upward and connected to the nozzle. The swirl mixer is fixed on the nozzle.

[0007] The swirl mixer comprises a cylinder, a bracket and swirl blades. The cylinder is a hollow structure with upper and lower parts. The inner wall of the cylinder is connected to the nozzle through the bracket. A plurality of swirl blades are fixed on the inner wall of the cylinder above the bracket in a circular array.

[0008] Through the setting of the swirl blades, the flue gas in the SCR denitrification system will generate a strong rotational motion after flowing through the swirl blades, which can suck in the ammonia gas sprayed from the upper nozzle of the ammonia injection branch pipe, so that the ammonia gas and the flue gas are strongly mixed, thereby enhancing the mixing effect of the flue gas and ammonia gas and improving the denitrification reaction efficiency.

[0009] Preferably, the bracket includes a collar and a connecting rod, the outer side of the collar is radially and evenly connected to the connecting rod, one end of the connecting rod away from the collar is connected to the inner wall of the cylinder, and the collar is sleeved and fixed on the nozzle.

[0010] Preferably, the central axis of the collar is the same as the central axis of the cylinder and the nozzle, so as to ensure that the smoke rotates evenly in the cylinder, thereby making the ammonia and the smoke mix evenly and improving the mixing effect of the ammonia and the smoke.

[0011] Preferably, both ends of the connecting rod are respectively fixed to the inner wall of the cylinder and the collar.

[0012] Preferably, the swirl blades are arranged in a spiral shape from the bottom to the top.

[0013] Preferably, the spiral directions of the swirl blades of adjacent swirl mixers are the same.

[0014] Preferably, the spiral directions of the swirl blades of adjacent swirl mixers are opposite.

[0015] Preferably, the top opening of the cylinder expands outward in a trumpet shape.

[0016] Preferably, a flow regulating valve is provided on the ammonia injection main pipe.

[0017] Preferably, the ends of the ammonia injection branch pipes away from the ammonia injection main pipe are distributed in a matrix pattern.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. Through the setting of the swirl blades, the flue gas in the SCR denitrification system will generate a strong rotational motion after passing through the swirl blades, which can suck the ammonia gas sprayed from the upper nozzle of the ammonia spray branch pipe, so that the ammonia gas and the flue gas are strongly mixed, thereby enhancing the mixing effect of the flue gas and ammonia gas and improving the denitrification reaction efficiency.

[0020] 2. By setting the center axis of the collar, the cylinder and the nozzle to be the same center axis, the flue gas can be ensured to rotate evenly in the cylinder, so that the ammonia and the flue gas can be mixed evenly, thereby improving the mixing effect of the ammonia and the flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of an ammonia injection grid of an SCR denitration system according to an embodiment of the present invention;

[0022] Figure 2 It is a schematic structural diagram of a cyclone mixer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described in conjunction with the accompanying drawings of the specification.

[0024] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] In this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically limited.

[0026] See also Figure 1 The present embodiment discloses an ammonia injection grid of an SCR denitration system, comprising an ammonia injection main pipe 1, an ammonia injection branch pipe 2, a nozzle 3 and a cyclone mixer 4, wherein a plurality of ammonia injection branch pipes 2 are fixed on and connected to the ammonia injection main pipe 1, and one end of the ammonia injection branch pipe 2 away from the ammonia injection main pipe 1 is arranged upward in a matrix manner and connected to the nozzle 3, and the cyclone mixer 4 is fixed on the nozzle 3.

[0027] See also Figure 2 The swirl mixer 4 includes a barrel 41, a bracket 42 and swirl blades 43. The barrel 41 is a hollow structure with the top opening of the barrel 41 expanding outward in a trumpet shape. The inner wall of the bottom of the barrel 41 is connected to the nozzle 3 through the bracket 42. The inner wall of the barrel 41 above the bracket 42 is fixed with a plurality of swirl blades 43 in a circular array. The swirl blades 43 are spirally arranged from the bottom to the top. The spiral directions of the swirl blades 43 of adjacent swirl mixers 4 are the same or opposite. In this embodiment, the spiral directions of the swirl blades 43 of adjacent swirl mixers 4 are the same.

[0028] By setting the swirl blades 43, the flue gas in the SCR denitrification system will generate a strong rotational motion after flowing through the swirl blades 43, which can suck in the ammonia gas sprayed from the upper nozzle 3 of the ammonia spray branch pipe 2, so that the ammonia gas and the flue gas are strongly mixed, thereby enhancing the mixing effect of the flue gas and ammonia gas and improving the denitrification reaction efficiency.

[0029] The bracket 42 includes a collar 421 and a connecting rod 422 . The connecting rod 422 is fixedly welded to the outer side of the collar 421 in a radially uniform manner. One end of the connecting rod 422 away from the collar 421 is welded to the inner wall of the cylinder 41 . The collar 421 is welded and sleeved on the outer wall of the nozzle 3 .

[0030] Furthermore, the central axis of the collar 421 is the same as the central axis of the cylinder 41 and the nozzle 3, ensuring that the smoke rotates evenly in the cylinder 41, thereby making the ammonia and the smoke mix evenly, thereby improving the mixing effect of the ammonia and the smoke.

[0031] Furthermore, a flow regulating valve (not shown) is provided on the ammonia injection main pipe 1 to control the output of the ammonia flow rate.

[0032] The working principle of the present invention is: according to the denitration requirements, the flow regulating valve on the ammonia injection main pipe 1 is adjusted to control the ammonia flow rate, and the upper nozzle 3 of the ammonia injection branch pipe 2 sprays ammonia. At the same time, the flue gas in the SCR denitration system flows through the ammonia injection grid and enters a plurality of cylinders 41 in a matrix. When the flue gas flows through the swirl blades 43, a strong rotational motion is generated, which can suck in the ammonia sprayed from the nozzle 3, so that the ammonia and the flue gas are strongly mixed, thereby enhancing the mixing effect of the flue gas and ammonia and improving the denitration reaction efficiency.

[0033] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0034] The above-described embodiments merely represent implementation methods of the invention. The protection scope of the present invention is not limited to the above-described embodiments. For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An ammonia injection grid for an SCR denitration system, characterized in that: It comprises an ammonia injection main pipe, an ammonia injection branch pipe, a nozzle and a swirl mixer, wherein a plurality of ammonia injection branch pipes are arranged on the ammonia injection main pipe, one end of the ammonia injection branch pipe away from the ammonia injection main pipe is arranged upward and connected to the nozzle, and the swirl mixer is fixed on the nozzle; The swirl mixer comprises a cylinder, a bracket and swirl blades, wherein the cylinder is a hollow structure with upper and lower parts, the inner wall of the cylinder is connected to the nozzle through the bracket, and a plurality of swirl blades are fixed on the inner wall of the cylinder above the bracket in a circular array; The bracket comprises a collar and a connecting rod, the outer side of the collar is evenly connected to the connecting rod in a radial manner, one end of the connecting rod away from the collar is connected to the inner wall of the cylinder, and the collar is sleeved and fixed on the nozzle; The swirl blades are arranged in a spiral shape from the bottom to the top.

2. The ammonia injection grid of the SCR denitration system according to claim 1, characterized in that: The central axis of the collar is the same as the central axis of the cylinder and the nozzle.

3. The ammonia injection grid of the SCR denitration system according to claim 1, characterized in that: The two ends of the connecting rod are respectively welded and fixed to the inner wall of the cylinder and the sleeve ring.

4. The ammonia injection grid of the SCR denitration system according to claim 1, characterized in that: The spiral directions of the swirl blades of adjacent swirl mixers are the same.

5. The ammonia injection grid of the SCR denitration system according to claim 1, characterized in that: The spiral directions of the swirl blades of adjacent swirl mixers are opposite.

6. The ammonia injection grid of the SCR denitration system according to claim 1, characterized in that: The top opening of the cylinder expands outward in a trumpet shape.

7. The ammonia injection grid of the SCR denitration system according to claim 1, characterized in that: The ammonia injection main pipe is provided with a flow regulating valve.

8. The ammonia injection grid of the SCR denitration system according to claim 1, characterized in that: The ends of the ammonia injection branch pipes away from the ammonia injection main pipe are distributed in a matrix pattern.

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