A flue gas side multi-tangential uniform pressure annular droplet generator

Abstract

A flue gas-side multi-tangential uniform pressure annular droplet generator belongs to the technical field of industrial flue gas treatment and droplet generation equipment. This invention solves the problems of uneven fluid spray coverage, blind spots, and severe lack of anti-corrosion systems in existing droplet generators. It includes an annular body and at least four tangential inlet pipes evenly distributed along the circumference of the annular body. The annular body includes an inner ring, an outer ring, and two annular plates. A staggered nozzle group is arranged along the circumference of the inner ring. The staggered nozzle group includes at least two rows of nozzles distributed axially along the inner ring, with each adjacent pair of nozzles circumferentially staggered. Each wall surface of the annular pressure-stabilizing channel, the inner wall surface of the tangential inlet pipes, and the inner wall of the bushing are all provided with an internal flow surface anti-corrosion layer. The inner sidewall of the inner ring, the sidewalls of the two annular plates facing away from the annular pressure-stabilizing channel, the two end faces of the bushing, and the outer wall surface of the bushing at both ends of the protruding hole base are all provided with a flue gas-side composite anti-corrosion layer. This invention is used for flue gas-side droplet generation.

Description

Technical Field

[0001] This invention relates to a multi-tangential uniform pressure annular droplet generator for flue gas side, belonging to the technical field of industrial flue gas treatment and droplet generation equipment. Background Technology

[0002] In the flue gas treatment process of thermal power plants and industrial kilns, flue gas humidification and conditioning, denitrification reducing agent atomization, and desulfurizing agent spraying in the tail flue are core technological steps to ensure environmental compliance and improve equipment energy efficiency. The annular droplet generator, as a core device in these scenarios, operates in a dual corrosive environment: the interior of the chamber comes into contact with clean water, alkaline denitrification agents, and acidic desulfurizing agents containing solids; the exterior and inner walls of the chamber are in direct contact with substances containing SO2 and NO. x High-temperature flue gas with high concentrations of dust can cause acidic gases in the flue gas to condense upon cooling, forming highly corrosive acid liquids. The dust can also cause continuous erosion and wear on the surface of the equipment.

[0003] Existing droplet generators suffer from the following significant drawbacks due to their unreasonable structural design and inadequate corrosion protection system:

[0004] 1. Insufficient corrosion resistance: Due to the different characteristics of the media in contact with different parts of the equipment, the corrosion situation faced by different parts also varies. The existing equipment only has basic anti-corrosion design for the sprayed media inside the cavity, completely ignoring all surfaces of the annular cavity exposed to the flue gas environment—including the inner wall with nozzles, the outer wall facing the flue pipe wall, and the upper and lower end faces. High-temperature flue gas containing sulfur and nitrogen oxides condenses on the equipment surface upon cooling, forming a strongly acidic condensate with a pH value ≤2, which quickly causes substrate corrosion and pitting. At the same time, the high concentration of dust in the flue gas will cause continuous erosion of the equipment surface, resulting in damage to the anti-corrosion layer, substrate corrosion, perforation, and leakage within 3 months, seriously affecting the equipment's lifespan and causing extremely high subsequent maintenance costs.

[0005] In addition, the nozzle structure design has inherent defects, making it the most common site for equipment corrosion and erosion failure. The nozzles in existing equipment only have internal overflow protection, leaving the nozzle outlet and orifice edges directly exposed to the flue gas environment. One end is subjected to scouring and wear from the high-speed solid desulfurizing agent inside, while the other end is subjected to erosion from flue gas dust and acidic condensate. Within 3 months, orifice corrosion and edge chipping, irregular orifice diameter expansion, complete disorder of the atomization cone angle, and complete loss of spray uniformity occur.

[0006] In addition, the existing equipment cavity structure has inherent defects that prevent it from achieving continuous and complete coverage of the anti-corrosion layer in all dimensions. The existing equipment cavities are divided into two categories, neither of which can meet the requirements of all-dimensional anti-corrosion: one type is a multi-segment welded spliced ​​cavity with a large number of circumferential and longitudinal welds. The welding stress and uneven surface at the welds will lead to insufficient adhesion of the anti-corrosion layer, making it very easy for the edges to peel, crack, and fall off, forming anti-corrosion breaks; the other type is a multi-segment hinged adjustable diameter cavity with a large number of movable hinge sealing gaps, which cannot achieve continuous coverage of the anti-corrosion layer. The hinges become the hardest-hit areas for corrosion. At the same time, adjusting the diameter will cause nozzle misalignment and tearing of the anti-corrosion layer, completely losing the protective effect.

[0007] 2. Traditional views hold that tangential inflow structures are prone to particle deposition and blockage within the flow channel, thus they are often abandoned in applications containing solid media such as desulfurization slurries, limiting the applicability of the equipment. Furthermore, due to insufficient structural design, the fluid jet coverage is uneven, with blind zones and inconsistent inlet pressure at each nozzle, leading to significant differences in flow rate and atomized particle size among the nozzles, making it difficult to meet high emission standards for droplet field uniformity.

[0008] In summary, existing droplet generators suffer from several technical challenges, including a severe lack of anti-corrosion systems, inherent failures in the nozzle structure, inability of the cavity structure to adapt to all-dimensional protection, and rapid corrosion and erosion failure on the flue gas side. These challenges severely restrict their widespread application in industrial tail-end flue gas environments. Therefore, there is an urgent need for a novel annular droplet generator that can simultaneously provide internal multi-media corrosion protection, full surface protection on the flue gas side, and wear-resistant and corrosion-resistant closed-loop nozzles, while also possessing good pressure uniform atomization performance and a stable and reliable structure. This would fundamentally solve the problem of equipment corrosion failure. Summary of the Invention

[0009] The present invention aims to solve the above-mentioned technical problems and provides a flue gas-side multi-tangential uniform pressure annular droplet generator.

[0010] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0011] A flue gas-side multi-tangential pressure-equalizing annular droplet generator includes an annular body and at least four tangential inlet pipes evenly distributed along the circumference of the annular body. The annular body comprises an inner ring, an outer ring, and two annular plates. The inner and outer rings are coaxially arranged from the inside out. The two ends of the inner and outer rings are sealed and integrally formed by the two annular plates. An annular pressure-stabilizing flow channel with equal cross-section is formed between the inner ring, outer ring, and the two annular plates.

[0012] The inner ring is provided with staggered nozzle groups along its circumference. The staggered nozzle groups include at least two rows of nozzles distributed along the axial direction of the inner ring, and each pair of adjacent rows of nozzles is circumferentially staggered.

[0013] At least four tangential inlet pipes are integrally formed and fixed to the outer ring and are connected to the annular pressure-stabilizing flow channel.

[0014] Each nozzle includes a nozzle body and a bushing. The nozzle body is a through hole formed on the inner ring. The bushing is coaxial and interference-fitted into the nozzle body, with both ends of the bushing protruding from both ends of the nozzle body.

[0015] The inner walls of the annular pressure-stabilizing channel, the inner wall of the tangential inlet pipe, and the inner wall of the bushing are all provided with an internal flow surface anti-corrosion layer.

[0016] The inner wall of the inner ring, the side walls of the two ring plates facing away from the annular pressure stabilizing channel, the two end faces of the bushing, and the outer wall of the bushing at both ends of the protruding hole substrate are all provided with a flue gas side composite anti-corrosion layer.

[0017] Furthermore, the internal flow surface anti-corrosion layer adopts basic protection or enhanced protection. When basic protection is adopted, the inner wall surface of each wall of the annular pressure stabilizing channel and the inner wall surface of the tangential inlet pipe are electrolytically polished, with an inner wall roughness Ra≤0.4μm and a passivation film with a thickness ≥8μm. When enhanced protection is adopted, the inner wall surface of each wall of the annular pressure stabilizing channel and the inner wall surface of the tangential inlet pipe are additionally coated with a fluoropolymer corrosion-resistant coating on the basis of basic protection. The coating material is ETFE or FEP, with a thickness of 50μm~100μm, a coating adhesion of ≥1 grade, and a pH resistance range of 1~14.

[0018] Furthermore, the flue gas side composite anti-corrosion layer includes a pretreatment underlayer, a cathodic protection primer layer, an anti-permeability intermediate layer, and a wear-resistant and weather-resistant surface layer. The pretreatment underlayer is sandblasted to Sa2.5 grade on the inner sidewall of the inner ring and the sidewall of the two ring plates facing away from the annular pressure-stabilizing channel, with a surface roughness Rz of 40~80μm. The dry film thickness of the cathodic protection primer layer is 60μm~80μm. The dry film thickness of the anti-permeability intermediate layer is 100μm~150μm. The dry film thickness of the wear-resistant and weather-resistant surface layer is 80μm~120μm, with a temperature resistance ≥300℃, a pH resistance of 1~14, and an Akron abrasion loss ≤0.05g / 1000r.

[0019] Furthermore, the cathodic protection primer layer uses epoxy zinc-rich primer, the anti-permeability intermediate layer uses glass flake epoxy putty, and the wear-resistant and weather-resistant top layer uses modified PTFE wear-resistant and anti-corrosion topcoat.

[0020] Furthermore, each tangential inlet pipe is arranged directly opposite the staggered nozzle group along the radial direction of the annular body.

[0021] Furthermore, there are four tangential inlet tubes, and the central angle between the central axes of two adjacent tangential inlet tubes is 90°.

[0022] Furthermore, the staggered nozzle group includes three rows of nozzles.

[0023] Furthermore, all nozzles have the same inner diameter, and the distance between two adjacent nozzles along the circumferential direction is less than the inner diameter of the nozzle.

[0024] Furthermore, the center-to-center distance between adjacent nozzles is 4mm to 10mm.

[0025] Furthermore, the bushing is a 95% alumina ceramic bushing or a reaction-sintered silicon carbide ceramic bushing. The inlet end of the bushing is provided with a rounded transition of R≥1mm, and the outlet end is provided with a flow-guiding chamfer of 30°~45°. The roughness of the inner wall of the channel is Ra≤0.8μm.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The droplet generator of this invention is compatible with multiple application scenarios such as clean water flue gas humidification, denitrification reducing agent atomization injection, and desulfurizing agent spray conditioning. At the same time, it provides all-dimensional anti-corrosion and wear-resistant protection for high-temperature flue gas environments containing sulfur, nitrogen oxides, and dust. It is also suitable for laboratory testing scenarios such as high-precision calibration of humidity sensors and construction of standard uniform humidity fields.

[0028] The inflow channels of each set of tangential inlet pipes are tangential to the outer circumference of the annular cavity, so that the fluid enters the annular pressure-stabilizing channel tangentially and forms a closed-loop circumferential vortex. The vortex momentum transfer is used to offset the pressure loss along the flow path. Under the conditions of clean water, alkaline denitrification agent, and acidic solid desulfurization agent, the full circumferential pressure deviation of the annular pressure-stabilizing channel is ≤±2%. In addition, the present invention uses tangential inflow for solid media. The continuous scouring effect of the vortex can prevent solid particles of solid desulfurization agent from settling and clogging in the channel.

[0029] Different anti-corrosion structures are installed in different areas of the droplet generator to form a full-area, multi-medium anti-corrosion system, covering all surfaces of the equipment that come into contact with the medium, with no blind spots. This significantly extends the service life and solves four major industry challenges: internal flow medium corrosion, acid and dust erosion on the flue gas side, cross-medium failure of nozzles, and corrosion at connection interfaces. Combined with the continuous, uninterrupted substrate of the integrated closed-loop cavity, the anti-corrosion layer achieves 100% full coverage with no weak points. Under high-sulfur, high-dust tail flue conditions, the equipment's continuous service life is ≥24 months, more than four times that of existing equipment, and maintenance costs are reduced by more than 80%.

[0030] The staggered nozzle array is arranged on the inner side of the flue of the annular main body, using a double-row or higher staggered arrangement. The upper and lower rows of nozzles are preferably staggered by 1 / 2 hole spacing in the circumferential direction to form a continuous equilateral triangular grid layout, ensuring that the flow characteristics and atomization effect of all nozzles are completely consistent. The center-to-center distance between adjacent nozzles is permanently constant, which, together with the pressure uniformity of the annular pressure-stabilizing flow channel, forms a uniform droplet spray structure with no blind spots in the entire circumference and a single-hole flow deviation of ≤3%.

[0031] The staggered nozzle group, the constant inner wall of the integrated annular cavity, and the uniform pressure characteristics of the annular pressure-stabilizing flow channel form a triple synergy. The integrated annular cavity ensures that the nozzle position is permanently constant without misalignment, the uniform pressure flow channel ensures that the inlet pressure of each nozzle is completely consistent, and the staggered nozzle group ensures that the spray coverage is uniform without blind spots. The combination of the three ultimately achieves a droplet field spatial uniformity of ≥98%, which can achieve uniform coverage of the entire cross section of the tail flue and greatly improve the mixing efficiency of reducing agent, desulfurizing agent and flue gas. Attached Figure Description

[0032] Figure 1 This is a three-dimensional structural diagram of the flue gas-side multi-tangential uniform pressure annular droplet generator of the present invention (annular plate not shown).

[0033] Figure 2 for Figure 1 Enlarged diagram of point A in the diagram;

[0034] Figure 3 for Figure 1 Enlarged diagram of point B in the diagram;

[0035] Figure 4 This is a top view schematic diagram of the flue gas side multi-tangential uniform pressure annular droplet generator of the present invention (annular plate not shown).

[0036] In the picture:

[0037] 1. Annular body; 11. Inner ring; 12. Outer ring; 13. Nozzle; 2. Tangential inlet pipe. Detailed Implementation

[0038] Specific implementation method one: Combining Figures 1-4 This description of embodiments provides a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] A flue gas-side multi-tangential pressure-equalizing annular droplet generator includes an annular body 1 and at least four tangential inlet pipes 2 evenly distributed circumferentially along the annular body 1. The annular body 1 includes an inner ring 11, an outer ring 12, and two annular plates. The inner ring 11 and the outer ring 12 are coaxially arranged from the inside to the outside. The two ends of the inner ring 11 and the outer ring 12 are sealed and integrally formed by the two annular plates. An annular pressure-stabilizing flow channel with equal cross-section is formed between the inner ring 11, the outer ring 12, and the two annular plates.

[0040] The inner ring 11 is provided with a staggered nozzle group along its circumference. The staggered nozzle group includes at least two rows of nozzles 13 distributed along the axial direction of the inner ring 11, and each pair of adjacent rows of nozzles 13 are staggered circumferentially.

[0041] At least four tangential inlet pipes 2 are integrally formed and fixed to the outer ring 12 and are connected to the annular pressure-stabilizing flow channel.

[0042] Each nozzle 13 includes a nozzle body and a bushing. The nozzle body is a through hole formed on the inner ring 11. The bushing is coaxial and interference-fitted into the nozzle body, with both ends of the bushing protruding from both ends of the nozzle body.

[0043] The inner walls of the annular pressure-stabilizing channel, the inner wall of the tangential inlet pipe 2, and the inner wall of the bushing are all provided with an internal flow surface anti-corrosion layer.

[0044] The inner wall of the inner ring 11, the side walls of the two ring plates facing away from the annular pressure stabilizing channel, the two end faces of the bushing, and the outer wall of the bushing at both ends of the protruding hole substrate are all provided with a flue gas side composite anti-corrosion layer.

[0045] The droplet generator of this invention is compatible with multiple application scenarios such as clean water flue gas humidification, denitrification reducing agent atomization injection, and desulfurizing agent spray conditioning. At the same time, it provides all-dimensional anti-corrosion and wear-resistant protection for high-temperature flue gas environments containing sulfur, nitrogen oxides, and dust. It is also suitable for laboratory testing scenarios such as high-precision calibration of humidity sensors and construction of standard uniform humidity fields.

[0046] The annular body 1 is a seamless, integrally spun annular cavity structure. The cavity forms a closed, uniform cross-section annular pressure-stabilizing flow channel without splicing welds, movable hinges, or structural breaks, providing a continuous and unbroken substrate carrier for the full-area multi-media anti-corrosion system. The smooth and undisturbed continuous flow channel will not interfere with the circumferential swirling flow formed by the tangential inflow, which is the core basis for achieving a full circumferential pressure deviation of ≤±2%. The integrally formed constant inner wall surface ensures that the nozzle 13 is permanently constant and without misalignment, which is the core prerequisite for achieving a droplet field uniformity of ≥98%.

[0047] The roundness tolerance of the cavity of the annular body 1 is ≤ ±0.1mm, and the straightness tolerance of the inner wall surface is ≤ ±0.05mm. Its base material is included in a graded corrosion resistance system, which is divided into three levels:

[0048] Basic grade: Made of 316L austenitic stainless steel, suitable for clean water, conventional urea / ammonia denitrification agents, and low sulfur flue gas conditions;

[0049] Advanced grade: Made of 2205 duplex stainless steel, its resistance to chloride ion stress corrosion is more than 3 times that of 316L stainless steel, and it is suitable for desulfurizing agents containing chloride ions, high-concentration denitrification agents, and medium-to-high sulfur flue gas conditions.

[0050] Special grade: Made of Hastelloy C276, suitable for high temperature and strong corrosion, high fluorine and high chlorine desulfurization and denitrification complex conditions, and high sulfur and high dust flue gas conditions;

[0051] The cavity of the annular body 1 is designed to withstand a pressure rating of ≥1.6MPa and a temperature range of -60℃ to 300℃. The cross-section of the cavity is a circular structure with equal cross-section.

[0052] The inlet channels of each set of tangential inlet pipes 2 are tangential to the outer circumference of the annular cavity, so that the fluid enters the annular pressure-stabilizing channel tangentially and forms a closed-loop circumferential vortex. The vortex momentum transfer is used to offset the pressure loss along the flow path. Under the conditions of clean water, alkaline denitrification agent, and acidic solid desulfurization agent, the full circumferential pressure deviation of the annular pressure-stabilizing channel is ≤±2%. In addition, the present invention uses tangential inlet for solid media. The continuous flushing effect of the vortex can prevent solid particles of solid desulfurization agent from settling and clogging in the channel.

[0053] The staggered nozzle group is arranged on the inner side of the flue of the annular main body 1, and adopts a double-row or more staggered arrangement structure. The upper and lower rows of nozzles 13 are preferably staggered by 1 / 2 hole spacing in the circumferential direction to form a continuous equilateral triangular grid layout. The hole diameter of the bushing in a single nozzle 13 is preferably uniformly 2mm, with a machining tolerance ≤±0.05mm and a hole position deviation ≤±0.03mm, to ensure that the flow characteristics and atomization effect of all nozzles 13 are completely consistent. The center-to-center distance between adjacent nozzles 13 is permanently constant, which, combined with the pressure uniformity of the annular pressure-stabilizing channel, forms a uniform droplet spray structure with no blind spots in the entire circumference and a single-hole flow deviation of ≤3%. The bushing wall thickness is preferably 1mm~1.5mm; it balances structural strength and installation compatibility, avoiding installation breakage and long-term erosion wear. The bushing and the hole base adopt an interference fit with an interference amount of 0.02mm~0.05mm, with no clearance, completely eliminating crevice corrosion, while ensuring that the bushing does not loosen or fall off under flue vibration conditions. The two ends of the bushing are respectively directed towards The internal flow channel and the external extension of the flue side of the cavity to the base of the orifice are 0.5mm~1mm, forming an orifice protection extension section that completely covers the inner and outer orifice edges of the spray hole 13 base. This ensures that all erosion and corrosion are borne by the ceramic bushing, and that acid and alkali media and dust do not come into contact with the stainless steel base. This solves the industry problem of orifice edge chipping and diameter expansion from the root. The anti-corrosion layer on the exposed surface of the orifice base is completely integrated with the anti-corrosion system on the flue gas side. The coating thickness is consistent with the coating of the surrounding base, with no breaks or steps, avoiding dust erosion and liquid accumulation that could cause the coating to peel off prematurely.

[0054] Different anti-corrosion structures are installed in different areas of the droplet generator to form a full-area, multi-medium anti-corrosion system, covering all surfaces of the equipment that come into contact with the medium, with no blind spots. This significantly extends the service life and solves four major industry challenges: internal flow medium corrosion, acid and dust erosion on the flue gas side, failure of the 13-channel nozzle across the medium, and corrosion at the connection interface. Combined with the continuous, uninterrupted substrate of the integrated closed-loop cavity, the anti-corrosion layer achieves 100% full coverage with no weak points. Under high-sulfur, high-dust tail flue conditions, the equipment's continuous service life is ≥24 months, more than four times that of existing equipment, and maintenance costs are reduced by more than 80%.

[0055] The full-area media-based anti-corrosion system includes the internal flow surface anti-corrosion layer and the flue gas side composite anti-corrosion layer.

[0056] The internal flow surface anti-corrosion layer covers the entire flow inner wall of the annular pressure stabilizing channel and the tangential inflow component, and is suitable for corrosion protection against clean water, alkaline denitrification agents, and acidic solid-containing desulfurization agents.

[0057] The composite anti-corrosion layer on the flue gas side is suitable for corrosion and erosion protection against high-temperature flue gas containing sulfur, nitrogen oxides, and dust.

[0058] The internal flow surface anti-corrosion layer covers the droplet generator that directly contacts substances containing SO2 and NO. x The surface of high-temperature flue gas with high concentration of dust is covered by the continuous surface of the integrated closed-loop cavity, eliminating the risk of coating cracking caused by weld seams or hinge breaks, and ensuring 100% full coverage of all surfaces exposed to the flue gas.

[0059] The nozzle 13 is a cross-media area, with the inlet end contacting the internal sprayed medium and the outlet end and the orifice edge contacting flue gas and dust. It is the most prone to corrosion and erosion. The anti-corrosion layer covers the entire channel and orifice edge of the nozzle 13, and is adapted to the dual corrosion and dust erosion protection of the sprayed medium and flue gas. The embedded bushing forms a fully closed-loop protection structure. The precise interference fit eliminates crevice corrosion. The orifice protection extensions extending from both ends completely cover the edge of the orifice substrate. The complete integration with the composite anti-corrosion layer on the flue gas side eliminates anti-corrosion breaks. It completely isolates the stainless steel orifice substrate from the corrosive environment in all directions, and completely solves the problems of corrosion chipping, orifice diameter expansion, and atomization failure that occur in the existing nozzle 13 after 3 months. The service life of the nozzle 13 is synchronized with that of the annular body 1.

[0060] One end of the tangential inlet pipe 2 is integrally formed and fixed to the outer ring 12, with no moving sealing links and no weak points in the weld, completely eliminating problems such as sealing failure at the hinge, weld leakage, and vibration misalignment. The vibration resistance of the equipment is improved by more than 10 times, and there are no vulnerable parts, which greatly reduces the operation and maintenance costs.

[0061] This invention integrates the ring-shaped main body 1 with the anti-corrosion system in a deep synergy. The seamless, one-piece molded cavity structure completely solves the technical problem of easy cracking and peeling of the anti-corrosion layer in spliced / hinged structures, which is the core prerequisite for the effective implementation of the full-area anti-corrosion system. At the same time, it ensures the stability of the flow field and the permanent constancy of the nozzle 13 arrangement, achieving a dual improvement in anti-corrosion performance and atomization performance.

[0062] At least four evenly distributed tangential inlet pipes 2, combined with seamless smooth flow channels, can achieve a full circumferential pressure deviation of ≤±2% and a flow deviation of ≤3% for each nozzle 13, even under high viscosity and solid-containing media conditions. Combined with a permanently constant staggered nozzle group, the droplet field spatial uniformity is ≥98%, which is more than 20% higher than existing equipment. This significantly improves the mixing efficiency of reducing agent, desulfurizing agent and flue gas, increases denitrification efficiency by 12%~15%, and reduces ammonia slip concentration by more than 70%.

[0063] One droplet generator can simultaneously support three core operating conditions: clean water humidification, alkaline denitrification agent spraying, and acidic solid desulfurization agent spraying. It is also suitable for all types of tail flue environments, from low sulfur to high sulfur and from low dust to high dust. There is no need to customize equipment for different operating conditions, reducing equipment procurement costs by more than 60%, and it has extremely strong versatility.

[0064] At least four tangential inlet pipes 2 can be fitted with an integrated pressure-stabilizing and distributing chamber at their other ends. This chamber uses the same level of corrosion-resistant material as the annular pressure-stabilizing flow channel. It features one main liquid supply inlet and four equal-diameter branch outlets, each connected to a corresponding tangential inlet pipe 2. The flow resistance of the branch outlets is completely consistent, further improving the pressure uniformity of the chamber under conditions involving solid and high-viscosity media. A full-bore drain hole with a corrosion-resistant plug is installed at the lowest point of the chamber, allowing for complete drainage of the medium during shutdown. The entire surface of the drain hole is treated with a corresponding anti-corrosion layer, and the connection interface is designed to prevent crevice corrosion.

[0065] The staggered nozzle group, the constant inner wall of the integrated annular cavity, and the uniform pressure characteristics of the annular pressure-stabilizing flow channel form a triple synergy. The integrated annular cavity ensures that the position of nozzle 13 is permanently constant without misalignment, the uniform pressure flow channel ensures that the inlet pressure of each nozzle 13 is completely consistent, and the staggered nozzle group ensures that the spray coverage is uniform without blind spots. The combination of the three ultimately achieves a droplet field spatial uniformity of ≥98%, which can achieve uniform coverage of the entire cross section of the tail flue and greatly improve the mixing efficiency of reducing agent, desulfurizing agent and flue gas.

[0066] The annular body 1 and the tangential inlet pipe 2 serve as the base of the droplet generator. Their materials are incorporated into a graded corrosion-resistant system, and can be adapted to 316L stainless steel, 2205 duplex stainless steel or Hastelloy C276 according to the corrosion intensity of the medium. The annular pressure-stabilizing flow channel is designed to withstand pressure ≥1.6MPa and has a temperature range of -60℃ to 300℃, making it suitable for all working conditions of the tail flue.

[0067] A full-bore drain hole with an anti-corrosion plug is set at the lowest point of the annular body 1. The inner wall of the drain hole is made of an internal flow surface anti-corrosion layer, and the exposed surface is made of a flue gas side composite anti-corrosion layer. The connection interface between the plug and the cavity is treated to prevent crevice corrosion.

[0068] The annular droplet generator of this invention achieves a continuous service life of ≥24 months under high sulfur and high dust tail flue conditions, which is more than 4 times that of existing equipment, while taking into account multi-scenario adaptability and high-precision atomization performance.

[0069] The internal flow surface anti-corrosion layer adopts either basic protection or reinforced protection. When using basic protection, the walls of the annular pressure-stabilizing channel and the inner wall of the tangential inlet pipe 2 are electrolytically polished, with an inner wall roughness Ra≤0.4μm, and a passivation film with a thickness ≥8μm is applied. When using reinforced protection, in addition to the basic protection, a fluoropolymer corrosion-resistant coating is added to the walls of the annular pressure-stabilizing channel and the inner wall of the tangential inlet pipe 2. The coating material is ETFE or FEP, with a thickness of 50μm~100μm, adhesion ≥1, and pH resistance ranging from 1 to 14. This design allows the basic protection to be suitable for clean water and conventional denitrification agent conditions, significantly reducing media retention and corrosion pitting. The reinforced protection is non-stick, erosion-resistant, and effectively resists the penetration corrosion of chloride and fluoride ions, making it suitable for acidic desulfurizing agents containing solids and highly corrosive conditions. The internal flow surface anti-corrosion layer provides 100% full coverage with no gaps.

[0070] The flue gas side composite anti-corrosion layer includes a pretreatment base layer, a cathodic protection primer layer, an anti-permeability intermediate layer, and a wear-resistant and weather-resistant surface layer. The pretreatment base layer is sandblasted to Sa2.5 grade on the inner side wall of the inner ring 11 and the side wall surface of the two ring plates facing away from the annular pressure stabilizing channel, with a surface roughness Rz of 40~80μm. The dry film thickness of the cathodic protection primer layer is 60μm~80μm. The dry film thickness of the anti-permeability intermediate layer is 100μm~150μm. The dry film thickness of the wear-resistant and weather-resistant surface layer is 80μm~120μm, with a temperature resistance of ≥300℃, a pH value resistance of 1~14, and an Akron abrasion loss of ≤0.05g / 1000r. This design ensures coating adhesion by removing oxide scale and rust through a pretreatment layer; provides cathodic protection to the substrate through a cathodic protection primer layer, preventing rust initiation; an anti-permeability intermediate layer blocks the penetration of acidic condensate from sulfur- and nitrogen-oxide-containing flue gas, eliminating substrate corrosion; and a wear-resistant and weather-resistant top layer resists flue gas dust erosion, preventing dust adhesion and aging. The total dry film thickness of the flue gas-side composite anti-corrosion layer is preferably ≥240μm, with a continuous and uninterrupted coating covering all surfaces exposed to the flue gas environment. By designing the flue gas-side composite anti-corrosion layer as a four-layer composite structure consisting of pretreatment, primer, intermediate layer, and top layer, it combines cathodic protection, anti-permeability, and wear and weather resistance, extending the acidic condensate penetration time by more than 10 times and improving dust erosion resistance by more than 8 times, completely solving the industry problem of equipment surface rust and anti-corrosion layer peeling.

[0071] The cathodic protection primer layer uses an epoxy zinc-rich primer, the anti-permeability intermediate layer uses glass flake epoxy putty, and the wear-resistant and weather-resistant top layer uses a modified PTFE wear-resistant and anti-corrosion topcoat. This design, using glass flake epoxy putty in the anti-permeability intermediate layer, utilizes the labyrinth effect of the glass flakes to block the penetration of acidic condensate formed by sulfur- and nitrogen-oxide-containing flue gas, thus preventing substrate corrosion.

[0072] Each tangential inlet pipe 2 is arranged radially opposite to the staggered nozzle group along the annular body 1.

[0073] There are four tangential inlet tubes 2, and the central angle between the central axes of two adjacent tangential inlet tubes 2 is 90°.

[0074] The staggered nozzle group includes three rows of nozzles 13.

[0075] All nozzles 13 have the same inner diameter, and the distance between two adjacent nozzles 13 along the circumferential direction is less than the inner diameter of the nozzle 13. This design further ensures uniform spray coverage without blind spots. The distance between two adjacent nozzles 13 is the minimum length of the inner ring 11 base between two adjacent nozzles 13. For operating conditions containing solid desulfurizing agents and high dust flue gas, the number of nozzles 13 rows shall not be less than 3 rows, the number of nozzles 13 in a single row shall not be less than 36, the machining tolerance of the nozzles 13 along the entire circumference shall be ≤ ±0.05mm, and the position deviation shall be ≤ ±0.03mm.

[0076] The center-to-center distance between adjacent nozzles 13 is 4mm to 10mm. With this design, the center-to-center distance between adjacent nozzles 13 is the distance between the central axes of the two nozzles 13.

[0077] The bushing is a 95% alumina ceramic bushing or a reaction-sintered silicon carbide ceramic bushing. The inlet end of the bushing has a rounded transition with a radius of R≥1mm, and the outlet end has a guide chamfer of 30°~45°. The inner wall roughness of the channel is Ra≤0.8μm. This design reduces particle erosion and media retention by providing a rounded transition with R≥1mm at the inlet end, and optimizes the atomization cone angle and improves spray uniformity by providing a guide chamfer of 30°~45° at the outlet end.

[0078] Specific Implementation Method Two: Combining Figures 1-4 This embodiment is applicable to flue gas humidification and conditioning in low-sulfur, low-dust tail flue gas ducts, as well as humidity sensor calibration scenarios. It is compatible with conventional low-concentration denitrification agent conditions. The specific layout of the anti-corrosion layer across the entire area is as follows:

[0079] 1. Integrated closed-loop ring body: Made of 316L stainless steel seamless spinning integral molding, without any splicing welds or moving hinge points. The outer diameter of the ring body is 200mm, the inner diameter is 160mm, the roundness tolerance of the ring body is ≤±0.1mm, the design pressure resistance is 1.6MPa, and the temperature resistance range is -20℃~200℃.

[0080] 2. Four tangential inlet pipes: integrally formed with the integrated closed-loop annular body, evenly distributed at 90° along the outer circumference of the annular body, the inlet channel is tangent to the cavity, the inlet pipe has an inner diameter of 15mm, and has a built-in 316L stainless steel rectifier grid. The connection interface adopts DN15 flange interface, and the four sets of interface specifications are completely consistent.

[0081] 3. Staggered nozzle group: It is set on the inner wall of the flue side of the cavity, and adopts a double-row staggered arrangement. The diameter of a single nozzle is uniformly 2mm, the machining tolerance is ±0.03mm, the position deviation is ≤±0.03mm, the center distance between adjacent nozzles is 6mm, and the upper and lower rows of nozzles are staggered by 1 / 2 hole distance. A total of 216 nozzles are set around the circumference. The nozzle adopts a full-channel composite anti-corrosion coating structure, with a R1mm rounded corner transition at the inlet end and a 30° guide chamfer at the outlet end.

[0082] 4. Comprehensive multi-media corrosion protection system:

[0083] Internal flow surface anti-corrosion layer: The entire flow inner wall is treated with electrolytic polishing + passivation composite treatment, with roughness Ra≤0.4μm, passivation film thickness≥8μm, and the entire nozzle channel is treated synchronously without any breaks;

[0084] Flue gas side composite anti-corrosion layer: adopts a four-layer composite structure, ① pretreatment: sandblasting to Sa2.5 grade, roughness Rz40~60μm; ② epoxy zinc-rich primer, dry film thickness 60μm; ③ glass flake epoxy putty intermediate layer, dry film thickness 100μm; ④ modified PTFE wear-resistant topcoat, dry film thickness 80μm; total dry film thickness 240μm, covering all flue gas exposed surfaces of the cavity, exposed surfaces of the inlet pipe, and the entire surface of the mounting feet;

[0085] Cross-medium corrosion protection of nozzles: The inner wall of the entire nozzle channel is consistent with the internal flow surface corrosion protection layer, and the edge of the outlet end orifice is completely connected with the composite corrosion protection layer on the flue gas side, with no exposed substrate.

[0086] Anti-corrosion at connection interface: The flange adopts a tongue and groove structure and is equipped with a 316L stainless steel + flexible graphite metal spiral wound gasket. After the exposed gaps of the flange are filled with epoxy sealant, the flue gas side is fully covered with an anti-corrosion layer.

[0087] Specific implementation method three: Combining Figures 1-4 This implementation method is suitable for SCR / SNCR denitrification ammonia water and urea reducing agent injection conditions in medium- and high-sulfur tail flue gas ducts. It is also compatible with clean water humidification conditions. The upgraded anti-corrosion layer layout for the entire area is as follows:

[0088] 1. Integrated closed-loop ring body: Made of 2205 duplex stainless steel seamless spinning integral molding, the ring cavity has an outer diameter of 300mm and an inner diameter of 240mm. It is designed to withstand a pressure of 2.5MPa and a temperature range of -40℃ to 250℃, and its resistance to chloride ion stress corrosion is significantly improved.

[0089] 2. Four tangential inlet pipes: integrally formed with the integrated closed-loop annular body, equipped with an integrated 2205 duplex stainless steel pressure stabilizing and distribution chamber, with one DN20 flange main liquid supply inlet and four DN15 equal diameter diversion outlets, which are respectively connected to the four tangential inlet pipes.

[0090] 3. Staggered nozzle group: It adopts a double-row staggered arrangement, with a single nozzle diameter of 2mm and a center-to-center distance of 8mm between adjacent nozzles. A total of 288 nozzles are set around the circumference. The nozzles adopt a full-channel composite anti-corrosion coating structure.

[0091] 4. Comprehensive multi-media corrosion protection system:

[0092] Internal flow surface anti-corrosion layer: On the basis of electrolytic polishing and passivation, an 80μm thick ETFE fluoropolymer anti-corrosion coating is added to cover the entire inner wall of the flow and the entire channel of the nozzle.

[0093] Flue gas side composite anti-corrosion layer: four-layer composite structure upgrade, ① sandblasting Sa2.5 grade, roughness Rz50~70μm; ② epoxy zinc-rich primer, dry film thickness 70μm; ③ glass flake epoxy putty intermediate layer, dry film thickness 120μm; ④ modified PTFE wear-resistant topcoat, dry film thickness 100μm; total dry film thickness 290μm, full coverage without blind spots;

[0094] Anti-corrosion measures at connection interfaces: The flange is equipped with 2205 stainless steel + flexible graphite metal spiral wound gasket, and all gaps are filled with epoxy sealant and then fully covered with an anti-corrosion layer.

[0095] Specific implementation method four: Combination Figures 1-4 This embodiment is suitable for combined operation of wet desulfurization agent spraying and denitrification reducing agent injection in high-sulfur and high-dust tail flue gas ducts. It is a full-featured, top-of-the-line model with comprehensive upgrades to the anti-corrosion layer across all areas as follows:

[0096] 1. Integrated closed-loop ring body: Made of 2205 duplex stainless steel seamless spinning integral molding, which can be upgraded to Hastelloy C276 for strong corrosion conditions. The outer diameter of the ring cavity is 400mm, the inner diameter is 320mm, the design pressure is 3.0MPa, and the temperature range is -60℃~300℃.

[0097] 2. Four tangential inlet pipes: integrally formed with the cavity, equipped with an integrated 2205 duplex stainless steel pressure stabilizing and distribution cavity, with one DN25 flange main liquid supply inlet and four DN20 equal diameter diversion outlets. The rectifier section has a built-in anti-settling rectifier grid to prevent the settling of desulfurizing agent solid particles.

[0098] 3. Staggered nozzle group: The nozzles are arranged in three staggered rows. The nozzles are embedded reaction sintered silicon carbide ceramic bushings with a fully closed-loop protective structure. The inner diameter of the bushing is uniformly 2mm with a machining tolerance of ±0.02mm and the bushing wall thickness is 1.2mm. The bushing is interference-fitted with the substrate with an interference of 0.03mm and no clearance. Both ends of the bushing extend 0.8mm into the cavity and the flue side of the substrate, forming a protective extension section at the nozzle opening that completely covers the edge of the substrate at the nozzle opening. The center-to-center distance between adjacent nozzles is 8mm. A total of 432 nozzles are set around the circumference. The inlet end is equipped with a 2mm rounded corner transition and the outlet end is equipped with a 45° guide chamfer.

[0099] 4. Comprehensive multi-media corrosion protection system:

[0100] Internal flow surface anti-corrosion layer: On the basis of electrolytic polishing and passivation, a 100μm thick FEP fluoropolymer anti-corrosion coating is added to cover the entire flow inner wall;

[0101] Flue gas side composite anti-corrosion layer: top-of-the-line four-layer composite structure, ① sandblasting Sa2.5 grade, roughness Rz60~80μm; ② epoxy zinc-rich primer, dry film thickness 80μm; ③ glass flake epoxy putty intermediate layer, dry film thickness 150μm; ④ modified PTFE wear-resistant topcoat, dry film thickness 120μm; total dry film thickness 350μm, full coverage without blind spots.

[0102] Cross-medium corrosion protection of nozzles: The silicon carbide ceramic bushing completely covers the entire nozzle channel and the edge of the nozzle opening, with no exposed substrate. The corrosion protection layer on the exposed surface of the nozzle substrate is completely integrated with the surrounding flue gas side corrosion protection system, with consistent thickness and no breaks.

[0103] Anti-corrosion of connection interface: FKM fluororubber seals are used, and FFKM perfluoroether rubber is upgraded for strong corrosion conditions. The flange is equipped with 2205 stainless steel + flexible graphite metal spiral wound gasket. After all gaps are completely sealed, an anti-corrosion layer is applied for full coverage.

[0104] A DN20 full-bore drain hole is provided at the lowest point of the cavity. The inner wall is covered with an internal flow-through anti-corrosion layer, the exposed surface is covered with a flue gas side composite anti-corrosion layer, and the connection interface is treated to prevent crevice corrosion.

[0105] To verify the anti-corrosion effect of the present invention, three comparative examples were set up. These examples used the exact same inflow structure, nozzle arrangement, and operating environment as the fourth embodiment of the present invention, differing only in the cavity structure and anti-corrosion system. A 1000-hour continuous operation test was conducted on-site in a high-sulfur, high-dust tail flue. The measured comparative data are as follows:

[0106] 1. Cavity Structure: The annular body of the present invention is integrally seamlessly formed; Comparative Example 1 is a welded spliced ​​cavity with 3 sections welded together and 3 annular welds, with only internal corrosion protection; Comparative Example 2 is a hinged cavity with 3 sections hinged together and 3 movable sealing points, with only internal corrosion protection; Comparative Example 3 is a welded spliced ​​cavity with 6 sections welded together and 6 annular welds, with internal + simple flue gas corrosion protection.

[0107] 2. Flue gas side corrosion protection system: The present invention is a four-layer composite structure with a total thickness of 350μm; Comparative Example 1 is a flue gas side corrosion protection system; Comparative Example 2 is a flue gas side corrosion protection system; Comparative Example 3 is a single-component organosilicon topcoat with a thickness of 80μm.

[0108] 3. Nozzle structure: The present invention is a ceramic bushing with full closed-loop protection; Comparative Example 1 is a stainless steel substrate with direct drilling without bushing; Comparative Example 2 is a stainless steel substrate with direct drilling without bushing; Comparative Example 3 is a ceramic bushing installed flush with the substrate without extension.

[0109] 4. Substrate corrosion after 1000 hours of operation: The present invention showed no rust or pitting, and the anti-corrosion layer was intact; Comparative Example 1 showed large-area rust on the surface, and pitting and perforation appeared at the weld; Comparative Example 2 showed severe rust at the hinge, and the seal failed and leaked; Comparative Example 3 showed large-area peeling of the anti-corrosion layer, and pitting appeared on the substrate.

[0110] 5. Nozzle condition after 1000 hours of operation: The bushing of this invention is intact, with no chipping or enlargement; Comparative Example 1: The nozzle edge is severely corroded and chipped, with an enlargement of ≥0.5mm; Comparative Example 2: The nozzle is misaligned, with edge corrosion and enlargement of ≥0.8mm | Corrosion in the gap between the bushing and the substrate, with chipping and enlargement of ≥0.3mm at the nozzle opening; Comparative Example 3: Corrosion in the gap between the bushing and the substrate, with chipping and enlargement of ≥0.3mm at the nozzle opening.

[0111] 6. Circumferential pressure deviation: ≤±1.8% for this invention; 9.6% for Comparative Example 1; 13.2% for Comparative Example 2; and 10.5% for Comparative Example 3.

[0112] 7. Droplet field uniformity: ≥98.2% for this invention; 83.5% for Comparative Example 1; 78.6% for Comparative Example 2; and 85.1% for Comparative Example 3.

[0113] 8. Predicted continuous fault-free life: ≥24 months for this invention; ≤5 months for Comparative Example 1; ≤3 months for Comparative Example 2; ≤8 months for Comparative Example 3.

[0114] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A flue gas-side multi-tangential uniform pressure annular droplet generator, characterized in that: The system includes an annular body (1) and at least four tangential inlet pipes (2) evenly distributed along the circumference of the annular body (1). The annular body (1) includes an inner ring (11), an outer ring (12), and two annular plates. The inner ring (11) and the outer ring (12) are coaxially arranged from the inside to the outside. The two ends of the inner ring (11) and the outer ring (12) are sealed and integrally formed by the two annular plates. An annular pressure-stabilizing flow channel with equal cross-section is formed between the inner ring (11), the outer ring (12), and the two annular plates. The inner ring (11) is provided with a staggered nozzle group along its circumference. The staggered nozzle group includes at least two rows of nozzles (13) distributed along the axial direction of the inner ring (11), and each pair of adjacent rows of nozzles (13) are staggered circumferentially. At least four tangential inlet pipes (2) are integrally formed and fixed to the outer ring (12) and are connected to the annular pressure-stabilizing flow channel. Each nozzle (13) includes a nozzle body and a bushing. The nozzle body is a through hole formed on the inner ring (11). The bushing is coaxial and interference-fitted into the nozzle body, with both ends of the bushing protruding from both ends of the nozzle body. The inner walls of the annular pressure-stabilizing channel, the inner wall of the tangential inlet pipe (2), and the inner wall of the bushing are all provided with an internal flow surface anti-corrosion layer. The inner wall of the inner ring (11), the side walls of the two ring plates facing away from the annular pressure stabilizing channel, the two end faces of the bushing, and the outer wall of the bushing at both ends of the protruding hole substrate are all provided with a flue gas side composite anti-corrosion layer.

2. The flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 1, characterized in that: The internal flow surface anti-corrosion layer adopts basic protection or enhanced protection. When basic protection is adopted, the inner wall surface of each wall of the annular pressure stabilizing channel and the inner wall surface of the tangential inlet pipe (2) are electrolytically polished, the inner wall roughness Ra≤0.4μm, and a passivation film is provided on the surface with a passivation film thickness≥8μm. When enhanced protection is adopted, the inner wall surface of each wall of the annular pressure stabilizing channel and the inner wall surface of the tangential inlet pipe (2) are provided with a fluoropolymer corrosion resistant coating on the basis of basic protection. The coating material is ETFE or FEP, the thickness is 50μm~100μm, the coating adhesion is ≥1 grade, and the pH value resistance range is 1~14.

3. The flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 1, characterized in that: The flue gas side composite anti-corrosion layer includes a pretreatment bottom layer, a cathodic protection primer layer, an anti-permeability intermediate layer and a wear-resistant and weather-resistant surface layer. The pretreatment bottom layer is sandblasted to Sa2.5 level on the inner side wall of the inner ring (11) and the side wall surface of the two ring plates facing away from the annular pressure stabilizing channel, with a surface roughness Rz40~80μm. The dry film thickness of the cathodic protection primer is 60μm~80μm; The dry film thickness of the anti-permeability intermediate layer is 100μm~150μm; the dry film thickness of the wear-resistant and weather-resistant surface layer is 80μm~120μm, the temperature resistance is ≥300℃, the pH value is 1~14, and the Akron abrasion loss is ≤0.05g / 1000r.

4. The flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 3, characterized in that: The cathodic protection primer layer uses epoxy zinc-rich primer, the anti-permeability intermediate layer uses glass flake epoxy putty, and the wear-resistant and weather-resistant top layer uses modified PTFE wear-resistant and anti-corrosion topcoat.

5. A flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 1, characterized in that: Each tangential inlet pipe (2) is arranged radially opposite to the staggered nozzle group along the annular body (1).

6. The flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 1, characterized in that: There are four tangential inlet tubes (2), and the central angle between the central axes of two adjacent tangential inlet tubes (2) is 90°.

7. A flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 1, characterized in that: The staggered nozzle group includes three rows of nozzles (13).

8. A flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 1, characterized in that: The inner diameter of each nozzle (13) is the same, and the distance between two adjacent nozzles (13) along the circumferential direction is less than the inner diameter of the nozzle (13).

9. A flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 8, characterized in that: The center-to-center distance between adjacent nozzles (13) is 4mm~10mm.

10. A flue gas-side multi-tangential uniform pressure annular droplet generator according to claim 1, characterized in that: The bushing is a 95% alumina ceramic bushing or a reaction-sintered silicon carbide ceramic bushing. The inlet end of the bushing is provided with a rounded transition of R≥1mm, and the outlet end is provided with a flow guide chamfer of 30°~45°. The roughness of the inner wall of the channel is Ra≤0.8μm.

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