Flue gas denitrification ammonia injection mixing system and its static mixing components

Abstract

This invention discloses a static mixing assembly disposed in a flue. The static mixing assembly includes: multiple mixing units uniformly distributed in the flue; each mixing unit includes: a reducing pipe extending axially along the flue with its wide end facing downwards; a guide pipe extending upwards along the narrow end of the reducing pipe; and a floating element disposed above the guide pipe. The floating element moves up and down along the axis of the reducing pipe, thereby changing the flow area between the edge of the floating element and the upper port of the guide pipe. This invention also discloses a flue gas denitrification ammonia injection mixing system. Through the coordinated design of the reducing pipe, the guide pipe, and the floating element, the floating element floats up and down with changes in gas flow rate. Especially during boiler low-load operation or deep peak shaving, the position of the floating element will move down to a new equilibrium position, reducing the flue gas flow area while maintaining the gas velocity. The vortex mixing effect generated on the back of the floating element after passing through it remains almost unchanged.

Description

Technical Field

[0001] This invention relates to the field of flue gas denitrification technology, and in particular to a flue gas denitrification ammonia injection mixing system and its static mixing components. Background Technology

[0002] Currently, the most widely used method for flue gas denitrification in thermal power plants is selective catalytic reduction (SCR) denitrification technology. The main principle of SCR denitrification technology is to inject ammonia, a reducing agent, into flue gas at 280℃~420℃ and mix it evenly. Under the action of a catalyst, NH3 reduces NO in the flue gas... x It is reduced to non-toxic and non-polluting nitrogen and water, thereby achieving the removal of NO from the mixed gas. x The purpose.

[0003] The flues of most coal-fired boilers in thermal power plants are rectangular, and the flue gas velocity and NO2 at the same cross-section within the flue are relatively uniform. x The distribution of the catalyst within the SCR reactor is typically uneven, sometimes differing by as much as double. If the flue gas velocity through the catalyst bed varies significantly, the residence time of the flue gas through the catalyst bed will be relatively short in areas with higher velocities, resulting in lower denitrification efficiency. Consequently, the NO content in the flue gas passing through the denitrification catalyst will be higher. x The content is difficult to meet environmental protection requirements, and the flue gas contains a lot of dust. In areas with higher gas velocities, the catalyst is more worn, and the catalyst's service life is reduced in these areas; in areas with lower gas velocities, the flue gas stays in the catalyst bed for a relatively longer time, and the denitrification efficiency is relatively high, but the catalyst utilization rate is insufficient in these areas.

[0004] In existing technologies, the mainstream approach to regulating the uniformity of the mixed gas flow field at the inlet of the SCR catalyst bed relies on ammonia injection mixing devices arranged within the flue gas duct, along with downstream baffles and rectifiers. While baffles and rectifiers primarily serve to achieve uniform gas velocity distribution and adjust velocity vector direction, their effect on NH3 concentration distribution is limited. Ammonia injection mixing devices, however, offer ideal results in achieving uniform gas velocity and NH3 concentration distribution. Therefore, the research and optimization of ammonia injection mixing devices has become a hot research topic in SCR denitrification technology in recent years.

[0005] Ammonia injection mixing systems are divided into ammonia injection grids (AIGs) and ammonia static mixers. An AIG is defined as an injection device that injects ammonia gas into the flue gas through a grid-like pipe, including the injection pipe, nozzle, support, and accessories. An ammonia static mixer is defined as a device that uses fixed components to change the flow state of ammonia gas and flue gas, thereby achieving thorough mixing and obtaining a higher NH3 / NO ratio. x Mixing efficiency.

[0006] Ammonia injection static mixers are all fixed equipment, and their structure is optimized according to the boiler's design load. Within the boiler's design load range, the ammonia-nitrogen molar ratio in the flue gas after passing through the ammonia injection static mixer meets the SCR denitrification requirements. However, continuous low-load operation or deep peak shaving of coal-fired power units will become the norm. For example, Unit 7 of Huaneng Shaanxi Qinling Power Generation Co., Ltd. even reached a deep peak shaving capacity of 27.27% of the rated load during formal operation, far below the design load. The flue gas velocity decreased significantly, and the uniformity of the ammonia-nitrogen molar ratio after passing through the ammonia injection static mixer deteriorated, failing to meet the requirements of the SCR denitrification system for the ammonia-nitrogen molar ratio in the flue gas. According to relevant industry standards, at 500mm before the inlet of the first layer catalyst in the SCR reactor, the deviation of the flow velocity at various points within 100% of the flue gas cross-section should be -15% to 15%, and the NH3 / NO ratio at various points within 100% of the flue gas cross-section should be... x The deviation of the molar ratio should be -10% to 10%. In addition, the static ammonia injector is generally set before the dust collector. The dust content in the flue gas is high. When the coal-fired power unit is operating at a low load for a long time or when it is deeply shaving the peak, the flue gas flow rate decreases and the ammonia injection amount also decreases. The ammonia nozzle is easily blocked by dust, resulting in uneven ammonia injection. Areas with excessive ammonia injection will form a large amount of ammonia escape.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] One of the objectives of this invention is to provide a flue gas denitrification ammonia injection mixing system and its static mixing components, thereby improving the gas mixing effect during low-load operation or deep peak shaving.

[0009] Another objective of this invention is to provide a flue gas denitrification ammonia injection mixing system and its static mixing components, thereby improving denitrification efficiency and ammonia utilization.

[0010] To achieve the above objectives, according to a first aspect of the present invention, a static mixing assembly is provided, disposed in a flue. The static mixing assembly includes: a plurality of mixing units uniformly distributed in the flue, each mixing unit including: a reducing pipe extending axially along the flue with its wide end facing downward; a guide pipe extending upward along the narrow end of the reducing pipe; and a floating element disposed above the guide pipe, the floating element moving up and down along the axis of the reducing pipe to change the flow area between the edge of the floating element and the upper port of the guide pipe.

[0011] Furthermore, in the above technical solution, the horizontal projected area of ​​the floating component is larger than the area of ​​the upper port of the guide straight pipe.

[0012] Furthermore, in the above technical solution, the floating component is connected to the guide straight pipe through an elastic component.

[0013] Furthermore, in the above technical solution, each mixing unit also includes: a guide rod, which is arranged along the axis of the reduced diameter tube, the lower end of the guide rod is connected to the straight guide tube, the upper end is provided with a limiting part, and the floating part is passed through the guide rod and floats up and down between the limiting part and the upper port of the straight guide tube along the guide rod.

[0014] Furthermore, in the above technical solution, the shape of the cross-section of the floating component is the same as the shape of the upper port of the guide straight pipe.

[0015] Furthermore, in the above technical solution, the upper end face of the reduced diameter pipe is circular or polygonal, and the lower end face is square or rectangular; the cross-sectional shape of the guide straight pipe is the same as the shape of the upper end face of the reduced diameter pipe.

[0016] Furthermore, in the above technical solution, the floating component is a circular piece, a polygonal piece, or an inverted conical structure.

[0017] According to a second aspect of the present invention, the present invention provides a flue gas denitrification ammonia injection mixing system, which includes, in sequence along the flue gas flow direction: a plurality of ammonia nozzles; and one or more static mixing components as described in any of the above technical solutions, wherein the mixing unit of the lowest layer static mixing component is arranged corresponding to the ammonia nozzle.

[0018] Furthermore, in the above technical solution, each mixing unit of the lowest layer static mixing component corresponds to the same number of ammonia nozzles.

[0019] Furthermore, in the above technical solution, each mixing unit corresponds to 1 to 9 ammonia nozzles.

[0020] Furthermore, in the above technical solution, when the static mixing component is multi-layered, the area of ​​the lower end face of the mixing unit of the upper static mixing component is 2 to 16 times the area of ​​the lower end face of the mixing unit of the lower static mixing component, and the distance between two adjacent static mixing components is 0.2 to 5m.

[0021] Furthermore, in the above technical solution, the flue upstream of the static mixing component is divided into multiple first ammonia injection zones, each first ammonia injection zone corresponding to one or more mixing units. The ammonia nozzle in each first ammonia injection zone is connected to the ammonia injection header, and the ammonia injection headers of the multiple first ammonia injection zones are connected to the ammonia injection main pipe. The ammonia injection header is equipped with a first flow regulating valve, and the ammonia injection main pipe is equipped with a second flow regulating valve. The flue downstream of the static mixing component is divided into multiple second ammonia injection zones, each second ammonia injection zone corresponding to one or more first ammonia injection zones. Each second ammonia injection zone is equipped with a flue gas detection unit.

[0022] Compared with the prior art, the present invention has one or more of the following beneficial effects:

[0023] 1. This invention utilizes a combined design of a reduced-diameter pipe, a straight guide pipe, and a floating component. Flue gas is accelerated through the reduced-diameter pipe, rectified in the straight guide pipe, and then impacts the floating component. When the boiler load decreases, especially during low-load operation or deep peak shaving, the flue gas volume decreases significantly, and the flue gas velocity entering the static mixing assembly decreases. The floating component shifts to a new equilibrium position, reducing the flue gas flow area. The gas velocity through the gap between the floating component and the straight guide pipe remains constant, and the vortex mixing effect generated on the back of the floating component remains almost unchanged. Therefore, the mixing effect of ammonia and flue gas is guaranteed, meeting the deviation requirements of the ammonia-nitrogen molar ratio at the catalyst inlet flue gas duct cross-section for SCR denitrification technology. When the boiler load increases, the floating component shifts to a new equilibrium position, increasing the flue gas flow area. With the flue gas density remaining almost constant or changing only slightly, the pressure difference across the floating component mainly depends on the weight of the floating component, and its pressure difference remains almost constant. Therefore, the pressure drop of the static mixing assembly remains almost constant or increases slightly, without causing a significant increase in the induced draft fan's power consumption.

[0024] 2. The flue gas flows from bottom to top through the static mixing component of this invention. The area of ​​the upper port of the narrow-diameter pipe is smaller than that of the lower port, and the flue gas flow area gradually decreases while the velocity gradually increases, which is beneficial to accelerating the mixing of ammonia and flue gas. The gas enters the guide straight pipe to achieve rectification, further improving the mixing degree of ammonia and flue gas. The mixed gas passes through the gap between the floating component and the guide straight pipe and forms a vortex on the back of the floating component, which promotes the forced mixing of ammonia and flue gas, greatly enhancing the mixing effect and improving the mixing uniformity of ammonia and flue gas, thereby shortening the distance required for uniform mixing.

[0025] 3. The horizontal projected area of ​​the floating component is larger than the upper port area of ​​the guide pipe, forming a shield. During normal boiler operation, large pieces of ash fall from the flue support and bends above the static mixing component due to the impact or disturbance of the flowing flue gas. Due to the shielding effect of the floating component, it can prevent the ammonia nozzles vertically arranged below the static mixing component along the flue gas flow direction from being blocked by large pieces of ash. When the boiler is shut down, the floating component falls under its own weight, sealing the upper port of the guide pipe or leaving a small gap, preventing dust settling in the flue or ash falling and blocking the ammonia nozzles below the static mixing component after manual cleaning of the flue. This solves the problem of SCR system nozzle blockage caused by ash in the flue, ensures the uniformity of ammonia injection from the ammonia injection grid nozzles, and can effectively extend the maintenance cycle of the unit.

[0026] 4. The static mixing components in the same layer can have the same structure, which enables modular mass production of static mixing components, reducing production and installation costs and improving product competitiveness; the static mixing components in different layers can be configured with different structures as needed, which can effectively reduce the weight of the mixer while ensuring the mixing effect, thereby reducing its production and manufacturing costs, and can also reduce the height of the static mixing components, thereby saving installation space.

[0027] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description

[0028] Figure 1 This is a cross-sectional schematic diagram of a mixing unit according to an embodiment of the present invention.

[0029] Figure 2 yes Figure 1 The diagram shows a top view of the hybrid unit.

[0030] Figure 3 This is a cross-sectional schematic diagram of a hybrid unit according to another embodiment of the present invention.

[0031] Figure 4 yes Figure 3 The diagram shows a top view of the hybrid unit.

[0032] Figure 5 A partial cross-sectional schematic diagram of a flue gas denitrification ammonia injection mixing system according to an embodiment of the present invention.

[0033] Figure 6 yes Figure 5 A schematic diagram showing the distribution of ammonia gas nozzles.

[0034] Figure 7 yes Figure 5 A top view of the static hybrid component.

[0035] Explanation of key figure labels:

[0036] 10-Fluorite, 100-Static mixing assembly, 110-Mixing unit, 111-Reduced diameter pipe, 112-Guide straight pipe, 113-Floating component, 114-Spring;

[0037] 210-Mixing unit, 211-Reduced diameter tube, 212-Flow guide tube, 213-Floating component, 214-Guide rod, 215-Limiting part, 216-Fixing component;

[0038] 300-Ammonia Nozzle. Detailed Implementation

[0039] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0040] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0041] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” other elements or features will be oriented “above” the element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. Objects may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0042] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0043] like Figure 1 , Figure 2 and Figure 5As shown, a static mixing assembly 100 according to a specific embodiment of the present invention is disposed in a flue 10. The static mixing assembly 100 includes a plurality of mixing units 110 uniformly distributed in the flue 10. Each mixing unit 110 includes a narrow-diameter pipe 111 extending axially along the flue 10. The narrow-diameter pipe 111 has a tubular structure that is wider at the bottom and narrower at the top, with its wide end facing downward. The narrow-diameter pipe 111 increases the flow rate of the mixed gas and accelerates mixing. The narrow end of the narrow-diameter pipe 111 extends upward to form a straight guide pipe 112, which is used to rectify the gas flow. A floating member 113 is provided above the straight guide pipe 112. The floating member 113 can move up and down along the axis of the narrow-diameter pipe 111, thereby changing the flow area between the edge of the floating member 113 and the upper port of the straight guide pipe 112. Flue gas flows upward through the static mixing assembly 100. The flow of flue gas impacts the floating member 113, causing it to float up and down until it reaches an equilibrium position. Therefore, the pressure difference of the flue gas passing through the floating member 113 remains almost constant, resulting in a nearly constant pressure drop in the static mixing assembly 100. This ensures effective mixing of ammonia and flue gas even at low flue gas flow rates. Furthermore, the gas can form a vortex on the back side of the floating member 113, accelerating gas mixing.

[0044] Furthermore, in one or more exemplary embodiments of the present invention, the horizontal projected area of ​​the floating member 113 is larger than the area of ​​the upper port of the guide pipe 112. The floating member 113 forms a shield for the guide pipe 112, thereby preventing large pieces of dust falling from above from entering the reduced diameter pipe 111 and its upstream. When the gas flow rate is very small or the operation is stopped, the floating member 113 blocks the upper port of the guide pipe 112 or leaves only a very small gap to prevent dust in the flue from settling or ash from falling and blocking structures such as the ammonia nozzle upstream of the static mixing component.

[0045] Furthermore, in one or more exemplary embodiments of the present invention, the floating member 113 is connected to the guide tube 112 via an elastic member. Exemplarily, in... Figure 1 In the illustrated embodiment, the elastic element is a spring 114, and the floating element 113 is connected to the side wall of the guide tube 112 via the spring 114. Further, in one or more exemplary embodiments of the present invention, the number of springs 114 is 2 to 4, evenly distributed around the circumference of the guide tube 112.

[0046] Furthermore, in one or more exemplary embodiments of the present invention, the upper and lower end faces of the reduced-diameter pipe 111 are both rectangular, and the cross-sectional shape of the guide straight pipe 112 is the same as the shape of the upper end face of the reduced-diameter pipe 111. It should be understood that the present invention is not limited thereto; the upper end face of the reduced-diameter pipe can be circular or polygonal, and the lower end face can be square or rectangular, and the shapes of the upper and lower end faces of the reduced-diameter pipe can be the same or different. The lower end face of the reduced-diameter pipe being square or rectangular allows it to fill the entire cross-section of the flue.

[0047] Furthermore, in one or more exemplary embodiments of the present invention, such as Figure 2 As shown, the floating element 113 is a rectangular piece. It should be understood that the present invention is not limited thereto; the floating element can be a circular piece, a polygonal piece, or an inverted conical structure. Preferably, but not limitingly, the cross-sectional shape of the floating element 113 is the same as the shape of the upper port of the guide tube 112.

[0048] Combination Figures 5-7 As shown, a flue gas denitrification ammonia mixing system according to one or more exemplary embodiments of the present invention comprises, in sequence along the flue gas flow direction, a plurality of ammonia nozzles 300 and a layer of static mixing assembly 100, wherein mixing units 110 of the static mixing assembly 100 are correspondingly arranged to the ammonia nozzles 300. Exemplarily, each mixing unit 110 of the static mixing assembly 100 corresponds to the same number of ammonia nozzles 300; for example, each mixing unit 110 corresponds to four ammonia nozzles 300. The present invention is not limited thereto.

[0049] Furthermore, in one or more exemplary embodiments of the present invention, the flue gas denitrification ammonia injection mixing system includes a multi-layer static mixing assembly, wherein the mixing units of the lowest layer static mixing assembly are correspondingly arranged with ammonia nozzles; each mixing unit of the lowest layer static mixing assembly corresponds to the same number of ammonia nozzles. Exemplarily, each mixing unit may correspond to 1 to 9 ammonia nozzles. Those skilled in the art can determine the number of ammonia nozzles based on the cross-sectional area of ​​the lower end face of the mixing unit to ensure the mixing effect of ammonia and flue gas; however, the present invention is not limited thereto.

[0050] Furthermore, in one or more exemplary embodiments of the present invention, when the static mixing component is multi-layered, the area of ​​the lower end face of the mixing unit of the upper static mixing component is 2 to 16 times the area of ​​the lower end face of the mixing unit of the lower static mixing component, and the distance between two adjacent static mixing components is 0.2 to 5m.

[0051] like Figure 3 and Figure 4As shown, the mixing unit 210 according to a specific embodiment of the present invention includes a narrowed-diameter pipe 211 extending axially along the flue. The narrowed-diameter pipe 211 is a tubular structure that is wider at the bottom and narrower at the top, with its wide end facing downwards. The narrowed-diameter pipe 211 increases the flow velocity of the mixed gas and accelerates mixing. The narrow end of the narrowed-diameter pipe 211 extends upwards to form a guide pipe 212. A floating member 213 is provided above the guide pipe 212. The floating member 213 can move up and down along the axis of the narrowed-diameter pipe 211, thereby changing the flow area between the edge of the floating member 213 and the upper port of the guide pipe 212. The flue gas flows through the mixing unit 210 from bottom to top. The flow of the flue gas impacts the floating member 213, which can float up and down under the action of the flue gas and reach an equilibrium position. Thus, the pressure difference of the flue gas passing through the floating member 213 remains almost constant, ensuring the mixing effect of ammonia and flue gas even when the flue gas flow rate is small. On the other hand, the gas can form a vortex on the back side of the floating member 213, accelerating gas mixing. The mixing unit 210 also includes a guide rod 214 arranged along the axis of the reduced-diameter tube 211. The lower end of the guide rod 214 is connected to the inner wall of the straight guide tube 212, and the upper end is provided with a limiting part 215. A floating member passes through the guide rod 214 and floats up and down between the limiting part 215 and the upper port of the straight guide tube 212 along the guide rod 214. Exemplarily, the floating member 213 can be connected to the straight guide tube 212 through a fixing member 216, but the present invention is not limited thereto.

[0052] Furthermore, in one or more exemplary embodiments of the present invention, the horizontal projected area of ​​the floating member 213 is larger than the area of ​​the upper port of the guide straight pipe 212. The floating member 213 forms a shield for the guide straight pipe 212, thereby preventing large pieces of dust falling from above from entering the reduced diameter pipe 211 and its upstream. When the gas flow rate is very small or the operation is stopped, the floating member 213 blocks the upper port of the guide straight pipe 212 or leaves only a very small gap, preventing dust in the flue from settling or ash from falling and blocking upstream ammonia nozzles and other structures.

[0053] Furthermore, in one or more exemplary embodiments of the present invention, the upper and lower end faces of the reduced-diameter pipe 111 are both square, and the cross-sectional shape of the guide straight pipe 212 is the same as the shape of the upper end face of the reduced-diameter pipe 211. It should be understood that the present invention is not limited thereto; the upper end face of the reduced-diameter pipe can be circular or polygonal, and the lower end face can be square or rectangular, and the shapes of the upper and lower end faces of the reduced-diameter pipe can be the same or different. The lower end face of the reduced-diameter pipe being square or rectangular allows it to fill the entire cross-section of the flue.

[0054] Furthermore, in one or more exemplary embodiments of the present invention, such as Figure 4As shown, the floating element 213 is a square piece. It should be understood that the present invention is not limited thereto; the floating element can be a circular piece, a polygonal piece, or an inverted conical structure. Preferably, but not limitingly, the cross-sectional shape of the floating element 213 is the same as the shape of the upper port of the guide tube 212.

[0055] The present invention will now be described in more detail by way of specific embodiments. It should be understood that the present invention is not limited thereto.

[0056] Example 1

[0057] In this embodiment, the flue gas denitrification ammonia injection mixing system includes, in sequence along the flue gas flow direction: multiple ammonia nozzles 300 and a layer of static mixing components 100.

[0058] refer to Figure 1 , 2 and Figures 5-7 As shown, the static mixing assembly 100 of this embodiment includes 32 mixing units 110, each mixing unit 110 corresponding to four ammonia nozzles 300. The structure of the mixing unit 110 is shown in the reference diagram. Figure 1 and Figure 2 As shown, the reduced diameter tube 111 has a truncated quadrangular structure with rectangular upper and lower end faces. The cross-section of the guide tube 112 is rectangular. The floating component 113 is a rectangular plate, which is fixed above the guide tube 112 by a spring 114. The horizontal projected area of ​​the floating component 113 is larger than the area of ​​the upper end face of the guide tube 112.

[0059] After a certain refining and chemical enterprise adopted the flue gas denitrification ammonia injection mixing system of this embodiment, the NH3 / NO content at various points in the flue gas at 500mm before the inlet of the first catalyst layer of the boiler SCR reactor, across 100% of the flue gas cross-section, was [data missing]. x The deviation of the molar ratio was reduced from ±21.7% to ±4.5%, which is better than the relevant industry requirements.

[0060] Example 2

[0061] In this embodiment, the flue gas denitrification ammonia injection mixing system uses mixing unit 210 to replace mixing unit 110 in embodiment 1, and other settings are the same as in embodiment 1.

[0062] Structural reference of hybrid unit 210 Figure 1 and Figure 2As shown, the reduced-diameter tube 211 has a truncated quadrangular structure with square upper and lower end faces. The cross-section of the guide tube 212 is square. The mixing unit 210 also includes a guide rod 214 arranged along the axis of the reduced-diameter tube 211. The lower end of the guide rod 214 is connected to the inner wall of the guide tube 212, and the upper end is provided with a limiting part 215. The floating member 213 is a square piece that passes through the guide rod 214 and floats up and down between the limiting part 215 and the upper end of the guide tube 212. The horizontal projected area of ​​the floating member 213 is larger than the area of ​​the upper end face of the guide tube 212.

[0063] After a power plant's coal-fired boiler adopted the flue gas denitrification ammonia injection mixing system of this embodiment, the NH3 / NO content at various points in the flue gas at 500mm before the inlet of the first catalyst layer of the boiler's SCR reactor, across 100% of the flue gas cross-section, was measured. x The deviation of the molar ratio was reduced from ±18.7% to ±4.2%, which is better than the relevant industry requirements.

[0064] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. Any simple modifications, equivalent changes, and alterations made to the foregoing exemplary embodiments should fall within the scope of protection of the present invention.

Claims

1. A static mixing component disposed in a flue, characterized in that, The static mixing component includes: Multiple mixing units are evenly distributed in the flue, each mixing unit comprising: A reduced-diameter pipe extends axially along the flue, with the wide end of the reduced-diameter pipe facing downwards; A straight guide tube extending upward along the narrow end of the reduced-diameter tube; and A floating element is positioned above the straight guide pipe. The floating element moves up and down along the axis of the reduced-diameter pipe, thereby changing the flow area between the edge of the floating element and the upper port of the straight guide pipe. The mixed gas passes through the gap between the floating element and the straight guide pipe, forming a vortex on the back of the floating element, which forces the ammonia and flue gas to mix. The horizontal projected area of ​​the floating element is larger than the area of ​​the upper port of the straight guide pipe, forming a shield. During normal boiler operation, the shielding effect of the floating element prevents the ammonia nozzles vertically arranged below the static mixing assembly along the flue gas flow direction from being blocked by large pieces of ash. When the boiler is shut down, the floating element falls under its own weight, sealing the upper port of the straight guide pipe or leaving a small gap, preventing dust in the flue from settling or ash from accumulating and falling during manual cleaning of the flue and blocking the ammonia nozzles below the static mixing assembly.

2. The static mixing component according to claim 1, characterized in that, The floating component is connected to the straight guide pipe via an elastic element.

3. The static mixing component according to claim 1, characterized in that, Each of the hybrid units further includes: A guide rod is provided along the axis of the reduced diameter tube. The lower end of the guide rod is connected to the straight guide tube, and the upper end is provided with a limiting part. The floating member passes through the guide rod and floats up and down along the guide rod between the limiting part and the upper port of the straight guide tube.

4. The static mixing component according to claim 1, characterized in that, The upper end face of the reduced diameter tube is circular or polygonal, and the lower end face is square or rectangular.

5. The static mixing component according to claim 1, characterized in that, The cross-sectional shape of the straight guide tube is the same as the shape of the upper end face of the reduced diameter tube.

6. The static mixing component according to claim 1, characterized in that, The shape of the cross-section of the floating component is the same as the shape of the upper port of the guide tube.

7. The static mixing component according to claim 1, characterized in that, The floating component is a circular piece, a polygonal piece, or an inverted conical structure.

8. A flue gas denitrification ammonia injection mixing system, characterized in that, Along the direction of flue gas flow, the following are included in sequence: Multiple ammonia nozzles; and One or more static mixing components as described in any one of claims 1 to 7, wherein the mixing unit of the lowest layer of the static mixing component is provided corresponding to the ammonia nozzle.

9. The flue gas denitrification ammonia injection mixing system according to claim 8, characterized in that, Each mixing unit of the lowest layer of the static mixing assembly corresponds to the same number of ammonia nozzles.

10. The flue gas denitrification ammonia injection mixing system according to claim 9, characterized in that, Each of the mixing units corresponds to 1 to 9 of the ammonia nozzles.

11. The flue gas denitrification ammonia injection mixing system according to claim 8, characterized in that, When the static mixing component is multi-layered, the area of ​​the lower end face of the mixing unit of the upper static mixing component is 2 to 16 times the area of ​​the lower end face of the mixing unit of the lower static mixing component.

12. The flue gas denitrification ammonia injection mixing system according to claim 8, characterized in that, When the static mixing component is multi-layered, the distance between two adjacent layers of the static mixing component is 0.2~5m.

Images