Ammonia gas and flue gas pipeline type mixer for flue gas denitration

Abstract

The invention provides an ammonia gas and flue gas pipeline type mixer for flue gas denitration, comprising: a main pipeline, which sequentially comprises a first pipe section, a reducing pipe section and a second pipe section along a flue gas flowing direction, the inner diameter of the first pipe section being greater than or equal to the inner diameter of the second pipe section; the inner ring pipeline is coaxially arranged in the first pipe section, and an annular gap is formed between the outer surface of the inner ring pipeline and the inner surface of the first pipe section; the atomizing nozzle is arranged at an opening, facing one side of the reducing pipe section, of the inner ring pipeline, and the atomizing nozzle is communicated with the reducing agent pipeline. According to the technical scheme, the problems that reactants are not uniformly distributed and a reducing agent is easily adhered to the inner wall can be solved, so that the denitration effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas denitration, and in particular to an ammonia and flue gas pipeline mixer for flue gas denitration. Background Art

[0002] Selective non-catalytic reduction (SNCR) flue gas denitrification technology produces denitrification reducing agent NH by pyrolysis of urea aqueous solution. 3 , the atomizing spray gun is set in the high-temperature flue at the top of the boiler furnace. Due to the large cross-section of the flue and the complex flow field, the urea decomposition products are unevenly distributed in the flue cross-section and cannot be evenly mixed with the flue gas, resulting in low denitrification efficiency, high ammonia escape at the outlet, and affecting the ammonia dosage control of the SCR device. When the selective catalytic reduction (SCR) denitrification technology uses urea pyrolysis or hydrolysis technology to prepare the reducing agent, it is necessary to set up a separate urea pyrolysis furnace or hydrolysis reactor, which requires a large investment.

[0003] When urea is pyrolyzed, due to uneven temperature distribution or insufficient heat supply in the pyrolysis chamber, urea is not completely decomposed in the pyrolysis chamber, resulting in the crystallization and aggregation of the intermediate product cyanic acid, which affects the normal operation of the denitrification system. In the case of a small amount of flue gas, such as diesel engine exhaust denitrification, when the urea aqueous solution is directly sprayed into the flue, the atomization is limited by the inner diameter of the flue, and it is easy to hit the inner wall of the flue and adhere to the deposit. Due to the effect of wall flow, the flow rate from the center of the flue to the inner wall of the flue gradually decreases, and the flue gas on the surface of the inner wall of the flue and the external environment undergo heat exchange, and the temperature is lower than the flue gas temperature in the center of the tube. Once the urea aqueous solution adheres to the inner wall, it is difficult to decompose it, which affects the utilization rate of urea and the denitrification effect. Summary of the invention

[0004] The present invention provides an ammonia and flue gas duct mixer for flue gas denitrification, which is used to solve the defects in the prior art that the flue gas denitrification effect is not ideal due to the uneven distribution of reactants and the easy adhesion of reducing agents to the inner wall, thereby improving the problems of uneven distribution of reactants and the easy adhesion of reducing agents to the inner wall, thereby improving the denitrification effect.

[0005] The present invention provides an ammonia and flue gas duct mixer for flue gas denitrification, comprising: a main duct, which includes a first pipe section, a reducing pipe section and a second pipe section in sequence along the flue gas flow direction, the inner diameter of the first pipe section being greater than or equal to the inner diameter of the second pipe section; an inner ring duct, which is coaxially arranged in the first pipe section, and an annular gap is formed between the outer surface of the inner ring duct and the inner surface of the first pipe section; an atomizing nozzle, which is arranged at an opening of the inner ring duct on one side of the reducing pipe section, and the atomizing nozzle is connected to a reducing agent pipeline.

[0006] According to an ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, a secondary contraction plate is arranged in the second pipe section, and the secondary contraction plate has a wide-mouth end facing the first pipe section and a narrow-mouth end facing away from the first pipe section; a guide cap is arranged downstream of the narrow-mouth end in the direction of flue gas flow, and the convex side of the guide cap faces the narrow-mouth end, and the concave side of the guide cap faces away from the narrow-mouth end.

[0007] According to an ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, the inner surface of the reducing pipe section is a conical surface, and the angle α between it and the inner surface of the first pipe section is greater than or equal to 150 degrees; and / or the inner surface of the secondary contraction plate is a conical surface, and the angle γ between it and the inner surface of the second pipe section is less than or equal to 30 degrees.

[0008] According to the ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, the convex side of the guide cap is a smooth arc shape; the radial dimension of the guide cap is greater than or equal to the radial dimension of the narrow end of the secondary contraction plate.

[0009] According to the ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, the main pipeline includes a diffusion pipe section; the diffusion pipe section forms a wide-angle shape at one end of the second pipe section away from the variable diameter pipe section.

[0010] According to the ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, the inner surface of the diffusion pipe section is a conical surface, and the angle β between the diffusion pipe section and the second pipe section is greater than or equal to 150 degrees.

[0011] According to the ammonia and flue gas pipeline mixer for flue gas denitrification provided by the present invention, the inner diameter of the inner ring pipeline is less than or equal to the inner diameter of the second pipe section; the inner diameter of the first pipe section is greater than the inner diameter of the second pipe section.

[0012] According to the ammonia and flue gas pipeline mixer for flue gas denitrification provided by the present invention, the atomizing nozzle is also connected to a compressed air or steam pipeline.

[0013] According to the ammonia and flue gas duct mixer for flue gas denitration provided by the present invention, the spray shape of the atomizing nozzle is a solid cone or a hollow cone.

[0014] According to an ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, the spray direction of the atomizing nozzle is in the same direction as the flue gas flow direction; or, the spray direction of the atomizing nozzle is opposite to the flue gas flow direction; or, there are multiple atomizing nozzles, some of which have spray directions in the same direction as the flue gas flow direction, and other parts of which have spray directions opposite to the flue gas flow direction.

[0015] The present invention provides an ammonia and flue gas pipeline mixer for flue gas denitration. Through the mixer, the flue gas first passes through the annular gap and is guided by the reducer pipe section, and then forms a high-speed flow on the inner wall surface of the pipeline mixer, and is mixed with the flue gas passing through the inner ring pipe when passing through the reducer pipe section. This high-speed flow can prevent the urea aqueous solution and its decomposition product HNCO from adhering to the inner surface of the second pipe section. When used for small-volume flue gas denitration, the high-speed flow of the flue gas on the inner wall surface of the pipeline mixer can prevent the local flue gas temperature from being too low due to heat exchange between the flue gas in a laminar flow state on the inner surface of the mixer and the outside air, thereby ensuring the complete decomposition of urea. In addition, through the atomizing nozzle, the reducing agent can be evenly sprayed into the flowing flue gas, thereby improving the problem of uneven distribution of the reactants. At the same time, since the reducing agent exists in an atomized form, its contact area with the flue gas can be increased, thereby improving the utilization rate of the reducing agent and the denitration effect.

[0016] Therefore, the ammonia and flue gas duct mixer for flue gas denitrification of the present invention can effectively solve the problems of uneven distribution of reactants and easy adhesion of reducing agents to the inner wall, thereby improving the denitrification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 This is one of the internal structure schematic diagrams of the ammonia and flue gas pipeline mixer for flue gas denitration provided by the present invention;

[0019] Figure 2 This is the second schematic diagram of the internal structure of the ammonia and flue gas pipeline mixer for flue gas denitration provided by the present invention;

[0020] Figure 3 It is a schematic diagram of the top view of the structure of the ammonia and flue gas pipeline mixer for flue gas denitration provided by the present invention;

[0021] Figure 4 It is a perspective schematic diagram of an ammonia and flue gas pipeline mixer for flue gas denitration provided by the present invention;

[0022] Reference numerals:

[0023] 110, first pipe section; 120, reducing pipe section; 130, second pipe section; 131, secondary contraction plate; 132, guide cap; 140, diffusion pipe section; 210, inner ring pipe; 211, annular gap; 220, atomizing nozzle; 221, reducing agent pipeline; 222, compressed air or steam pipeline. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0026] Combine the following Figure 1-Figure 4 The specific implementation of the ammonia and flue gas pipeline mixer for flue gas denitrification of the present invention is described.

[0027] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the present invention provides an ammonia and flue gas duct mixer for flue gas denitrification, comprising: a main pipeline, which includes a first pipe section 110, a reducing pipe section 120 and a second pipe section 130 in sequence along the flue gas flow direction, and the inner diameter of the first pipe section 110 is greater than or equal to the inner diameter of the second pipe section 130; an inner ring pipe 210, which is coaxially arranged in the first pipe section 110, and an annular gap 211 is formed between the outer surface of the inner ring pipe 210 and the inner surface of the first pipe section 110; an atomizing nozzle 220, which is arranged at the opening of the inner ring pipe 210 facing the reducing pipe section 120, and the atomizing nozzle 220 is connected to the reducing agent pipeline 221.

[0028] Through the above-mentioned flue gas denitrification ammonia and flue gas pipeline mixer, the flue gas first passes through the annular gap 211 and is guided by the reducer 120, and then forms a high-speed flow on the inner wall surface of the pipeline mixer, and is mixed with the flue gas passing through the inner ring pipe 210 when passing through the reducer 120. This high-speed flow can prevent the urea aqueous solution and its decomposition product HNCO from adhering to the inner surface of the second pipe section 130. When used for small-volume flue gas denitrification, the high-speed flow of the flue gas on the inner wall surface of the pipeline mixer can prevent the local flue gas temperature from being too low due to heat exchange between the flue gas in a laminar flow state on the inner surface of the mixer and the outside air, thereby ensuring the complete decomposition of urea. In addition, through the atomizing nozzle 220, the reducing agent can be evenly sprayed into the flowing flue gas, thereby improving the problem of uneven distribution of the reactants. At the same time, since the reducing agent exists in an atomized form, its contact area with the flue gas can be increased, thereby improving the utilization rate of the reducing agent and the denitrification effect.

[0029] According to the present invention, a flue gas denitrification ammonia and flue gas pipeline mixer is provided, such as Figure 1 , Figure 2 and Figure 4 As shown, a secondary contraction plate 131 is provided in the second pipe section 130, and the secondary contraction plate 131 has a wide end facing the first pipe section 110 and a narrow end facing away from the first pipe section 110; a guide vent 132 is provided downstream of the narrow end in the direction of smoke flow. The guide vent 132 can be a flat plate, or preferably a convex structure. The convex side of the guide vent 132 faces the narrow end, and the concave side of the guide vent 132 faces away from the narrow end.

[0030] After the flue gas flows through the atomizing nozzle 220, the mixed gas of the flue gas and the reducing agent gas passes through the gap between the secondary contraction plate 131 and the guide cap 132 and the second pipe section 130. In this process, the flue gas changes direction continuously, so that the flue gas and the urea decomposition products can be mixed violently. The guide cap 132 is arranged at the outlet of the secondary contraction plate 131, and the contraction openings of the reducer pipe section 120 and the secondary contraction plate 131 preferably coincide with the axis of the guide cap 132. When the mixed gas passes through, a negative pressure is generated on the concave side of the guide cap 132. The mixed gas flows out from the narrow end, and after passing through the guide cap 132, the pressure of the mixed gas is uneven on the cross section of the flue behind the guide cap 132, causing the mixed gas to move radially behind the guide cap 132, thereby promoting the radial uniform distribution of the mixed gas in the pipe section behind the guide cap.

[0031] Among them, the main purpose of the secondary contraction plate 131 is that when the mixed gas passes through, the diameter from the wide end to the narrow end gradually decreases, so that the flow rate of the mixed gas gradually increases. For example, the average flow rate of the mixed gas after passing through the reducer 120 is 10 to 30 m / s. After passing through the secondary contraction plate 131, the flow rate of the mixed gas flowing out from the narrow end increases to 20 to 40 m / s. The accelerated mixed gas can give full play to the role of the guide vent 132, increase the pressure difference between the convex side and the concave side, and improve the mixing effect of the mixed gas after passing through the guide vent 132. The guide vent 132 can be in the shape of an upwardly convex arc plate, a conical plate, etc.

[0032] According to the present invention, a flue gas denitrification ammonia and flue gas pipeline mixer is provided, such as Figure 1 and Figure 2 As shown, the inner surface of the above-mentioned reducing pipe section 120 is preferably a conical surface, and the angle α between it and the inner surface of the first pipe section 110 is greater than or equal to 150 degrees; and / or, the inner surface of the secondary contraction plate 131 is a conical surface, and the angle γ between it and the inner surface of the second pipe section 130 is less than or equal to 30 degrees.

[0033] Among them, the angle α is greater than or equal to 150 degrees, so that the guide angle of the reducer pipe section 120 is an obtuse angle greater than or equal to 15 degrees, so that when the smoke passes through the reducer pipe section 120, the guide angle of the smoke is smaller, so the resistance generated is smaller, which is conducive to the flow of smoke. On the other hand, the angle γ is less than or equal to 30 degrees, and the guide angle of the secondary contraction plate 131 is also an obtuse angle greater than or equal to 15 degrees, so that when the mixed gas passes through the secondary contraction plate 131, the guide angle of the smoke is smaller, so the resistance generated is smaller. Preferably, according to actual conditions, the above-mentioned angle α is between 150 degrees and 175 degrees; the above-mentioned angle γ is between 5 degrees and 30 degrees. Further preferably, the angle α is an obtuse angle, the angle γ is an acute angle, and the sum of the angle α and the angle γ is equal to 180 degrees.

[0034] According to an ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, the convex side of the above-mentioned guide cap 132 is preferably in a smooth arc shape; the radial dimension of the guide cap 132 is greater than or equal to the radial dimension of the narrow end of the secondary contraction plate 131, so that the guide cap 132 can fully play the role of guiding and mixing the mixed gas flowing out of the narrow end.

[0035] The convex side of the guide cap 132 is preferably in a smooth arc shape, which helps to reduce flow resistance and make the mixed gas flow more smoothly. At the same time, the radial dimension of the guide cap 132 is greater than or equal to the radial dimension of the narrow end of the secondary contraction plate 131, so that the guide cap 132 can fully play the role of guiding and mixing the mixed gas flowing out of the narrow end. The outer surface of the guide cap 132 adopts a smooth arc structure. This design can effectively prevent dust in the flue gas from depositing on its surface, thereby keeping the equipment clean and efficient.

[0036] In addition, the guide cap 132 is coaxially arranged with the narrow end, the wide end, the atomizing nozzle 220, the inner ring pipe 210 and the main pipe at a certain distance outside the outlet of the narrow end of the secondary contraction plate 131. This coaxial arrangement can ensure the relative position of each component is accurate, so as to work better together.

[0037] Through the above implementation, the performance and efficiency of the ammonia and flue gas pipeline mixer for flue gas denitrification can be further improved. At the same time, the various functional structures coaxially arranged along the flue gas flow direction help to reduce the volume and cost of the equipment, making the design of the entire mixer more efficient and economical.

[0038] According to the present invention, a flue gas denitrification ammonia and flue gas pipeline mixer is provided, such as Figure 1 and Figure 2 As shown, the main pipeline preferably further includes a diffuser section 140. The diffuser section 140 forms a wide-angle shape at one end of the second section 130 away from the reducer section 120. The diffuser section 140 is located at one end of the second section 130 away from the reducer section 120 and forms a wide-angle shape, so that the flow rate of the mixed gas gradually decreases after entering the diffuser section 140, thereby better allowing the reaction products to be fully and evenly mixed.

[0039] Among them, the guide cap 132 is preferably arranged at the junction of the diffusion pipe section 140 and the second pipe section 130, and this position can better guide the mixed gas into the diffusion pipe section 140. After the mixed gas passes through the guide cap 132, the concave sides of the diffusion pipe section 140 and the guide cap 132 provide radial pressure difference at the same time. This radial pressure difference can further improve the radial mixing efficiency of the mixed gas. Through the above embodiment, the performance and efficiency of the ammonia and flue gas duct mixer for flue gas denitrification can be further improved. The design of the diffusion pipe section 140 and the guide cap 132 can make the mixed gas mix better, thereby improving the denitrification effect.

[0040] Further, according to the ammonia and flue gas duct mixer for flue gas denitration provided by the present invention, the inner surface of the diffusion pipe section 140 is a conical surface, and the angle β between the diffusion pipe section 140 and the second pipe section 130 is greater than or equal to 150 degrees. The angle β can be between 150 and 180 degrees. Preferably, the angle β is the same as the angle α, which is conducive to complementing the flow rate changes of the flue gas entering the mixer and the mixed gas flowing out of the mixer, so that the operation of the entire flue gas denitration system is more stable.

[0041] According to the ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, the inner diameter of the inner ring pipe 210 is preferably less than or equal to the inner diameter of the second pipe section 130; the inner diameter of the first pipe section 110 is preferably larger than the inner diameter of the second pipe section 130. Among them, the flue gas flowing in the inner ring pipe 210 can directly flow to the second pipe section 130 at a constant speed; and the flue gas flowing in the annular gap 211 is accelerated along the inner wall of the main pipe due to the guiding effect of the reducer pipe, on the one hand, preventing the reducing agent sprayed by the atomizing nozzle 220 from adhering to the reducer pipe section 120, and on the other hand, preventing the flue gas close to the inner wall of the main pipe from losing heat or slowing down too much. According to a preferred embodiment of the present invention, the inner diameter of the inner ring pipe 210 is d1, the inner diameter of the second pipe section 130 is d2, and the inner diameter of the first pipe section 110 is d3. Figure 3 As shown, where d1 = (0.6 ~ 1.0) d2, d2 = (0.6 ~ 1.0) d3.

[0042] According to the ammonia and flue gas pipeline mixer for flue gas denitration provided by the present invention, the atomizing nozzle 220 is also connected to the compressed air or steam pipeline 222. The compressed air or steam pipeline 222 provides air or steam to promote the diffusion and reaction efficiency of the reducing agent.

[0043] Specifically, when the reducing agent pipeline 221 provides a urea aqueous solution, the compressed air or steam pipeline 222 is used to supply compressed air or steam for atomizing the urea aqueous solution; when the reducing agent pipeline 221 provides an ammonia aqueous solution, the compressed air or steam pipeline 222 is used to supply compressed air or steam for atomizing the ammonia aqueous solution; when the reducing agent pipeline 221 provides ammonia gas, the compressed air or steam pipeline 222 is used to supply air or steam for diluting the ammonia gas.

[0044] According to the ammonia and flue gas duct mixer for flue gas denitrification provided by the present invention, the spray shape of the atomizing nozzle 220 is a solid cone or a hollow cone. The spray shape of the atomizing nozzle 220 is designed to be a solid cone or a hollow cone. Such a design can ensure that the spray range is large enough while also controlling the spray direction to a certain extent.

[0045] Taking the reducing agent as urea aqueous solution as an example, when the urea aqueous solution is sprayed through the atomizing nozzle 220, most of the urea aqueous solution will immediately evaporate and decompose into ammonia and HNCO. HNCO will further thermally decompose into NH 3 and CO 2 In this way, a small amount of urea aqueous solution will be sprayed onto the inner wall of the reducer pipe section 120 or the second pipe section 130. After the flue gas flows through the inner ring pipe 210 and the annular gap 211, the flow rate will increase and then enter the reducer pipe section 120. In this process, the flue gas in the outer ring will be affected by inertia and accelerate along the tangent direction of the inner wall of the reducer pipe section 120 to enter the second pipe section 130. In this way, the urea solution sprayed onto the inner walls of the reducer pipe section 120 and the second pipe section 130 will be entrained and mixed into the high-speed flowing flue gas, undergoing heat exchange with it and decomposing into CO 2 and NH 3 .

[0046] The above solution can effectively prevent the urea aqueous solution from directly contacting the inner wall of the reducing pipe section 120 and the second pipe section 130 and being deposited. This can not only improve the utilization rate of the urea aqueous solution, but also avoid problems such as equipment blockage and corrosion caused by deposition, thereby extending the service life of the equipment. At the same time, this design also helps to improve the denitrification efficiency because it can increase the probability of the urea aqueous solution fully contacting and reacting with the flue gas.

[0047] According to the above-mentioned flue gas denitrification ammonia and flue gas pipeline mixer, as Figure 1 As shown, the spray direction of the atomizing nozzle 220 can be along the direction of smoke flow; or Figure 2As shown, the spray direction of the atomizing nozzle 220 can also be opposite to the flow direction of the smoke; or, there are multiple atomizing nozzles 220, of which the spray direction of some atomizing nozzles 220 is in the same direction as the flow direction of the smoke, and the spray direction of other atomizing nozzles 220 is opposite to the flow direction of the smoke. Different atomizing nozzle 220 settings can be set according to actual needs.

[0048] The scheme of the present invention is suitable for the denitration of dusty flue gas, especially the denitration of flue gas when the reducing agent is prepared by pyrolysis of urea aqueous solution, such as the denitration of flue gas in catalytic cracking units, the denitration of flue gas in coal-fired boilers, and the denitration of exhaust gas from diesel / fuel oil engines. The flue gas temperature should be greater than or equal to 150°C. For the denitration of atmospheric flue gas, it is preferred that a plurality of flue gas denitration ammonia and flue gas monomer pipeline mixers are arranged in parallel in the cross section of the flue.

[0049] Each mixer at least includes: a main pipe, which includes a first pipe section 110, a diameter-reducing pipe section 120 and a second pipe section 130 in sequence along the flue gas flow direction, wherein the inner diameter of the first pipe section 110 is greater than or equal to the inner diameter of the second pipe section 130. An inner ring pipe 210 is coaxially arranged in the first pipe section 110, and an annular gap 211 is formed between the outer surface of the inner ring pipe 210 and the inner surface of the first pipe section 110. An atomizing nozzle 220 is arranged at the opening of the inner ring pipe 210 facing the diameter-reducing pipe section 120, and is connected to the reducing agent pipeline 221.

[0050] In this structure, the flue gas first passes through the annular gap 211 and is guided by the reducer 120, and then forms a high-speed flow on the inner wall surface of the pipeline mixer. When the flue gas passes through the reducer 120, it will mix with the flue gas passing through the inner ring pipe 210. This high-speed flow can prevent the urea aqueous solution and its decomposition product HNCO from adhering to the inner surface of the second pipe section 130. When used for small-volume flue gas denitrification, the high-speed flow of the flue gas on the inner wall surface of the pipeline mixer can prevent the local flue gas temperature from being too low due to heat exchange between the flue gas in a laminar flow state on the inner surface of the mixer and the outside air, thereby ensuring the complete decomposition of urea.

[0051] In addition, the reducing agent can be uniformly sprayed into the flowing flue gas through the atomizing nozzle 220, thereby improving the problem of uneven distribution of reactants. At the same time, since the reducing agent exists in the form of atomization, its contact area with the flue gas can be increased, and it can be easily carried and moved by the accelerated flue gas that adheres to the inner wall of the main pipeline, thereby improving the utilization rate of the reducing agent and the denitration effect. This design helps to improve the denitration efficiency while reducing ammonia escape and operating costs.

[0052] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flue gas pipeline mixer for ammonia and flue gas denitrification, It is characterized in that include: A main pipe, comprising a first pipe section (110), a diameter-reducing pipe section (120) and a second pipe section (130) in sequence along a flue gas flow direction, wherein an inner diameter of the first pipe section (110) is greater than or equal to an inner diameter of the second pipe section (130); an inner ring pipe (210) coaxially arranged in the first pipe section (110), and an annular gap (211) is formed between the outer surface of the inner ring pipe (210) and the inner surface of the first pipe section (110); An atomizing nozzle (220) is arranged at an opening of the inner ring pipe (210) on a side facing the reducing pipe section (120), and the atomizing nozzle (220) is connected to a reducing agent pipeline (221).

2. The ammonia and flue gas pipeline mixer for flue gas denitration according to claim 1, It is characterized in that A secondary contraction plate (131) is arranged in the second pipe section (130), and the secondary contraction plate (131) has a wide end facing the first pipe section (110) and a narrow end facing away from the first pipe section (110); A guide cap (132) is provided downstream of the narrow end in the direction of smoke flow, with the convex side of the guide cap (132) facing toward the narrow end and the concave side of the guide cap (132) facing away from the narrow end.

3. The ammonia and flue gas pipeline mixer for flue gas denitration according to claim 2, It is characterized in that The inner surface of the reducing pipe section (120) is a conical surface, and the angle α between the reducing pipe section (120) and the inner surface of the first pipe section (110) is greater than or equal to 150 degrees; And / or, the inner surface of the secondary contraction plate (131) is a conical surface, and the angle γ between the conical surface and the inner surface of the second pipe section (130) is less than or equal to 30 degrees.

4. The ammonia and flue gas pipeline mixer for flue gas denitration according to claim 2, It is characterized in that The convex side of the guide cap (132) is in a smooth arc shape; The radial dimension of the guide cap (132) is greater than or equal to the radial dimension of the narrow end of the secondary contraction plate (131).

5. The ammonia and flue gas pipeline mixer for flue gas denitration according to any one of claims 2 to 4, It is characterized in that The main pipeline includes a diffuser section (140); The diffuser pipe section (140) forms a wide-angle shape at one end of the second pipe section (130) away from the reducer pipe section (120).

6. The ammonia and flue gas pipeline mixer for flue gas denitration according to claim 5, It is characterized in that The inner surface of the diffuser pipe section (140) is a conical surface, and the angle β between the diffuser pipe section (140) and the second pipe section (130) is greater than or equal to 150 degrees.

7. The ammonia and flue gas pipeline mixer for flue gas denitration according to claim 1, It is characterized in that The inner diameter of the inner ring pipe (210) is smaller than or equal to the inner diameter of the second pipe section (130); The inner diameter of the first pipe section (110) is greater than the inner diameter of the second pipe section (130).

8. The ammonia and flue gas pipeline mixer for flue gas denitration according to claim 1, It is characterized in that The atomizing nozzle (220) is also connected to a compressed air or steam pipeline (222).

9. The ammonia and flue gas pipeline mixer for flue gas denitration according to claim 1, It is characterized in that The spray shape of the atomizing nozzle (220) is a solid cone or a hollow cone.

10. The ammonia and flue gas pipeline mixer for flue gas denitration according to claim 9, It is characterized in that The spray direction of the atomizing nozzle (220) is in the direction of the smoke flow; or, the spray direction of the atomizing nozzle (220) is in the direction opposite to the smoke flow; or, there are multiple atomizing nozzles (220), wherein the spray direction of some of the atomizing nozzles (220) is in the direction of the smoke flow, and the spray direction of another part of the atomizing nozzles (220) is in the direction opposite to the smoke flow.

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