Coal-fired boiler flue gas SO2 removal and low-temperature waste heat recovery system

Abstract

The application discloses a coal-fired boiler flue gas SO2 removal and low-temperature waste heat recovery system and belongs to the technical field of environmental protection. The system comprises a rectifying tower, the rectifying tower is provided with a rectifying cavity, the rectifying cavity is provided with an outlet, the desulfurizing tower is provided with an air inlet at the bottom, the air inlet and the outlet are in communication with each other, a rectifier is arranged at the air inlet, the desulfurizing tower is connected with a condensing cooling tower, the inner wall of the condensing cooling tower is provided with a flow collecting groove, the flow collecting groove is connected with the desulfurizing tower, a plurality of heat exchange pipes are evenly distributed in the rectifying cavity and the condensing cooling tower, the heat exchange pipes are provided with flow blocking fins, the flow blocking fins are two, are arranged towards the direction of airflow and are provided at an angle of 120 degrees, a condensing grid is arranged in the condensing cooling tower and is located above the heat exchange pipes. The technical problem of poor integration of the low-temperature waste heat recovery and desulfurization process of the coal-fired boiler flue gas in the prior art is solved.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection technology, specifically relating to a system for SO2 removal and low-temperature waste heat recovery from flue gas of a coal-fired boiler. Background Technology

[0002] In existing technologies, coal-fired boilers are core thermal energy equipment in industries such as power, chemical, and heating. The combustion of coal generates a large amount of industrial flue gas, containing components such as sulfur dioxide (SO2), dust, low-temperature water vapor, and low-temperature waste heat. SO2 is a toxic and harmful acidic gas; direct emissions can cause acid rain, air pollution, and other environmental problems, severely damaging the ecological environment and endangering human health. However, the large amount of low-temperature waste heat contained in coal-fired boiler flue gas is a clean energy source with significant recovery value in industrial production. Currently, with continuously tightening environmental emission limits and increasingly stringent requirements for industrial energy conservation and carbon reduction, efficient desulfurization of coal-fired boiler flue gas and the resource recovery of low-temperature waste heat have become key research directions in the field of industrial environmental protection and energy conservation.

[0003] Currently, most existing flue gas treatment systems for coal-fired boilers adopt a split structure with independent desulfurization and independent waste heat recovery. This results in low equipment integration, large footprint, and high operating costs. Conventional desulfurization processes often use spray desulfurization towers to directly desulfurize the flue gas. However, when the flue gas enters the desulfurization tower, problems such as turbulent airflow, flow deviation, and uneven flow velocity occur, leading to uneven contact between the flue gas and the desulfurization spray liquid inside the tower. This makes it easy for some flue gas to short-circuit and escape, significantly reducing SO2 removal efficiency and resulting in poor desulfurization stability, making it difficult to meet ultra-low emission requirements. Summary of the Invention

[0004] The purpose of this invention is to provide a system for SO2 removal and low-temperature waste heat recovery from flue gas of coal-fired boilers, so as to achieve integrated treatment of SO2 removal and low-temperature waste heat recovery from flue gas of coal-fired boilers.

[0005] To achieve the above objectives, embodiments of the present invention provide a SO2 removal and low-temperature waste heat recovery system for flue gas from a coal-fired boiler, comprising: A rectifier tower having a rectifier cavity having an outlet; A desulfurization tower, wherein the bottom of the desulfurization tower has an air inlet, the air inlet is connected to the outlet, and a rectifier is provided at the air inlet; A condensing cooling tower, wherein the desulfurization tower leads to the condensing cooling tower, and the inner wall of the condensing cooling tower has a flow-gathering groove, which leads to the desulfurization tower; The heat exchange tubes are a plurality of tubes, which are evenly distributed in the rectifier cavity and the condensation cooling tower. The heat exchange tubes have baffles, and there are two baffles, which are set at a 120-degree angle to the direction of airflow. A condensation grid is disposed inside the condensation cooling tower and located above the heat exchange tubes.

[0006] As a further technical solution, the rectifier cavity is a rectangular cavity, and the heat exchange tubes in the rectifier cavity are divided into two groups. Each group of heat exchange tubes consists of several rows. The adjacent rows of heat exchange tubes are spaced apart to form an air passage gap. The two groups of heat exchange tubes are arranged opposite to each other and cross each other. The heat exchange tubes are inclined relative to the horizontal plane.

[0007] As a further technical solution, the baffle vane located in the rectification cavity has a baffle portion, which is a plurality of such baffle portions located on the side of the baffle vane facing the airflow direction and arranged perpendicular to the horizontal plane, in order to increase the heat exchange area and disrupt the swirling flow on the outer side of the baffle vane.

[0008] As a further technical solution, the baffle fin has slots, and several slots are arranged in a row. The baffle part has an insertion part, which is located in the slot. The baffle fin has a slot on the side away from the heat exchange tube. A swinging plug is provided in the slot. The swinging plug is used to swing with the change of airflow velocity in the rectifier cavity when the airflow velocity changes, so as to vibrate and clean the surface of the baffle fin.

[0009] As a further technical solution, the rectifier includes a plurality of baffle columns arranged in a row, and two baffle plates are oscillatingly sleeved on the baffle columns. The two baffle plates are connected by an elastic element, which is used to provide a force for the two baffle plates to move closer to each other. The two baffle plates oscillate under the action of airflow, and the included angle after oscillation is between 90 degrees and 150 degrees.

[0010] As a further technical solution, the root of the baffle plate has a pressure relief hole, which is arranged along the length direction of the baffle plate, and the width of the pressure relief hole is smaller than the thickness of the baffle plate.

[0011] As a further technical solution, it also includes: The liquid storage tank is connected to the desulfurization tower through the liquid storage tank. The liquid storage tank is used to store the desulfurization solution. The liquid collection tank is a spiral groove. Several heat exchange tubes are arranged along the edge of the liquid collection tank. The baffles of the heat exchange tubes extend into the liquid collection tank. The lower section of the liquid collection tank has an extension that extends toward the center of the desulfurization tower.

[0012] As a further technical solution, the deflector has a guide groove, the guide groove is guided along the length direction of the deflector, each deflector has a plurality of guide grooves arranged along the width direction, the guide groove has a diversion groove, the diversion groove has a support groove, the support groove extends from the diversion groove to both sides perpendicular to the diversion groove, the bottom of the support groove has a liquid collection groove, the liquid collection groove is used to collect the condensate condensed at the diversion groove and the support groove and introduce it into the liquid collection groove.

[0013] As a further technical solution, the desulfurization tower is equipped with several layers of sprayers, each layer of sprayers having several liquid delivery pipes, each liquid delivery pipe having a liquid delivery plate, and there are two liquid delivery plates arranged at a 120-degree angle. Each liquid delivery plate has a liquid outlet on its surface, and the liquid outlets of the two liquid delivery plates are arranged opposite to each other. The liquid delivery plates are used to intercept gas, and the spray liquid sprayed through the liquid outlets achieves efficient desulfurization.

[0014] As a further technical solution, the width of the liquid delivery plate is greater than the diameter of the liquid delivery pipe.

[0015] The significant technical effects of the embodiments of the present invention are as follows: This invention provides a SO2 removal and low-temperature waste heat recovery system for coal-fired boiler flue gas. The system utilizes a rectifier tower with internal heat exchange tubes to achieve initial flue gas rectification and preliminary waste heat recovery, eliminating turbulence and flow deviation, and ensuring a uniform and stable flue gas output. The rectifier at the inlet regulates the flue gas entering the desulfurization tower, improving the uniformity of contact between the flue gas and desulfurization liquid inside the tower and enhancing SO2 removal efficiency. The heat exchange tubes in the condensation cooling tower perform deep waste heat recovery from the low-temperature flue gas after desulfurization. Combined with the upper condensation grid, this enhances the flue gas condensation and cooling effect, allowing residual water vapor and trace pollutants in the flue gas to fully condense and precipitate. Simultaneously, the inner wall condensation tank collects the condensate and returns it to the desulfurization tower, achieving a closed-loop circulation of liquid resources and reducing chemical waste and wastewater discharge. Two baffles arranged at a 120-degree angle can block and disperse the flue gas flow through the heat exchange tube, prolong the contact heat exchange time between the flue gas and the heat exchange tube, increase the effective heat exchange area, improve the efficiency of low-temperature waste heat recovery, and realize the functions of efficient desulfurization of flue gas and efficient recovery of low-temperature waste heat in coal-fired boilers, with good operational stability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1This is a schematic diagram of the SO2 removal and low-temperature waste heat recovery system for flue gas from a coal-fired boiler in one embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of a portion of the heat exchange tubes within the central rectifier cavity; Figure 3 for Figure 2 Schematic diagram of the heat exchange tube structure; Figure 4 for Figure 1 A schematic diagram of the baffle plates and baffle columns in the intermediate rectifier; Figure 5 for Figure 1 A schematic diagram of the heat exchange tubes installed at the cohesive flow channel; Figure 6 for Figure 1 A partial structural diagram of the cohesive flow channel; Figure 7 for Figure 1 Schematic diagram of the liquid delivery pipe and related structures at the central sprayer; In the diagram: Rectifier tower-1, Rectifier cavity-101, Outlet-102, Desulfurization tower-2, Inlet-201, Rectifier-8, Condensation cooling tower-3, Concentrating tank-301, Heat exchange tube-4, Baffle fin-5, Condensation grid-6, Air passage gap-401, Baffle part-501, Slot-502, Insert-503, Card slot-504, Swing insert-7, Baffle column-801, Baffle plate-802, Elastic element-803, Pressure relief hole-804, Liquid storage tank-9, Extension part-302, Guide channel-505, Drain channel-506, Support channel-507, Concentrating tank-508, Sprayer-202, Liquid delivery pipe-203, Liquid delivery plate-204, Liquid outlet-205. Detailed Implementation

[0018] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0020] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0023] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0024] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation", "connection", "linking", and "fixing" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components.

[0025] Please see Figures 1-7This invention illustrates an embodiment of a coal-fired boiler flue gas SO2 removal and low-temperature waste heat recovery system. The system includes a rectifier tower 1, a desulfurization tower 2, a condensation cooling tower 3, heat exchange tubes 4, baffles 5, a condensation grid 6, and a rectifier 8. The rectifier tower 1 has a rectifier chamber 101 inside, with an outlet 102 at its end for regulating and discharging the flue gas flow. The desulfurization tower 2 has an inlet 201 at its bottom, which is connected to the outlet 102 of the rectifier chamber 101, thus connecting the flue gas passages of the rectifier tower 1 and the desulfurization tower 2. The rectifier 8 is fixedly installed at the inlet 201 to perform secondary rectification and flow stabilization on the flue gas entering the desulfurization tower 2. The flue gas outlet of desulfurization tower 2 is connected to condensation cooling tower 3. A flow-gathering groove 301 is fixedly opened on the inner wall of condensation cooling tower 3. The flow-gathering groove 301 is connected to the inside of desulfurization tower 2 through a pipeline, so that the condensed and collected liquid can be returned to the inside of desulfurization tower 2 for recycling. Several heat exchange tubes 4 are set, all evenly distributed inside the rectifying cavity 101 and inside the condensation cooling tower 3. At the same time, several heat exchange tubes 4 are also arranged at the outlet 102 of the rectifying cavity 101. Each heat exchange tube 4 is fixedly equipped with two baffles 5 on its outer side. The two baffles 5 are arranged facing the flue gas flow direction, and the included angle between them is set to 120 degrees. The condensation grid 6 is fixedly installed inside the condensation cooling tower 3, and the installation position is in the area above the heat exchange tubes 4 inside the condensation cooling tower 3.

[0026] The rectifier tower 1, in conjunction with the internal heat exchange tubes 4, achieves preliminary rectification of flue gas and initial waste heat recovery, eliminating turbulence and deviation in flue gas flow, and ensuring uniform and stable output of flue gas. The rectifier 8 at the inlet 201 regulates the state of the flue gas entering the desulfurization tower 2, improving the uniformity of contact between the flue gas and desulfurization liquid inside the desulfurization tower 2, and enhancing SO2 removal efficiency. The heat exchange tubes 4 in the condensation cooling tower 3 can perform deep waste heat recovery on the low-temperature flue gas after desulfurization, and together with the condensation grid 6 above, enhance the condensation and cooling effect of the flue gas, allowing residual water vapor and trace pollutants in the flue gas to be fully condensed and precipitated. At the same time, the inner wall concentrator 301 can collect the condensate and return it to the desulfurization tower 2, realizing a closed-loop circulation of liquid resources, reducing chemical waste and wastewater discharge. Two baffles 5 arranged at a 120-degree angle can block and disperse the flue gas flow through the heat exchange tube 4, prolong the contact heat exchange time between the flue gas and the heat exchange tube 4, increase the effective heat exchange area, improve the low-temperature waste heat recovery efficiency, and realize the functions of efficient desulfurization of flue gas and efficient recovery of low-temperature waste heat in coal-fired boilers, with good operational stability.

[0027] As a specific embodiment, the rectifier chamber 101 of the rectifier tower 1 is configured as a rectangular cavity structure. The heat exchange tubes 4 are arranged in two groups. Each group of heat exchange tubes 4 contains multiple rows of individual heat exchange tubes 4. Adjacent rows of heat exchange tubes 4 within the same group are arranged at intervals, and an air gap 401 is formed between adjacent rows to allow flue gas to flow. The two groups of heat exchange tubes 4 are arranged in a relative position and are staggered to each other. At the same time, all heat exchange tubes 4 are installed at an angle relative to the horizontal plane.

[0028] The rectifier cavity 101 is designed as a rectangular cavity to avoid the stagnation of flue gas at the corners of a circular cavity, thus improving the overall uniformity of flue gas flow. Two sets of staggered and inclined heat exchange tubes 4, combined with air gaps 401, can create multi-layered, multi-angle turbulence and heat exchange for the flue gas. Compared to a parallel heat exchange structure, this eliminates dead zones in flue gas flow, allowing the flue gas to fully contact the tube walls of the heat exchange tubes 4 from all directions without any dead zones. The inclined arrangement of the heat exchange tubes 4 extends the flue gas flow path, increasing the flue gas heat exchange time. Simultaneously, the staggered arrangement gradually disperses the laminar flow of the flue gas, enhancing the turbulent heat exchange effect and improving the low-temperature waste heat recovery efficiency within the rectifier cavity 101. The regular air gaps 401 ensure smooth flue gas flow, avoiding airflow blockage and excessive resistance caused by densely arranged heat exchange tubes, thus balancing heat exchange efficiency and flue gas flow resistance.

[0029] As a specific embodiment, the baffle 5 arranged inside the rectifier cavity 101 is integrally provided with a plurality of baffle parts 501. All baffle parts 501 are arranged on the side of the baffle 5 facing the flow of flue gas, and the baffle parts 501 are fixedly arranged perpendicular to the horizontal plane.

[0030] By vertically setting several baffles 501 on the airflow side of the baffle 5, the flue gas flow passing through the baffle 5 is dispersed, and the swirling and eddy current phenomena formed on the outer side of the baffle 5 due to airflow scouring are destroyed, thus avoiding insufficient heat exchange caused by the rapid passage of swirling airflow over the heat exchange tube 4. At the same time, the baffles 501 directly increase the total contact heat exchange area between the heat exchange tube 4 and the flue gas, improving the waste heat exchange efficiency of the flue gas in the rectifier cavity 101. The vertically arranged baffles 501 have strong structural stability and can continuously turbulently move the flue gas, causing the flue gas flow to merge rapidly, reducing the local temperature difference of the flue gas, making the overall waste heat recovery of the flue gas more uniform and thorough. At the same time, it can weaken the impact of airflow turbulence on the equipment structure, reduce equipment operating noise and vibration, and improve the system operating stability.

[0031] In a specific embodiment, the surface of the baffle 5 has several regularly arranged slots 502, and the bottom of the baffle part 501 is integrally provided with an insertion part 503. The baffle part 501 is correspondingly inserted and fixed inside the slot 502 through the insertion part 503, realizing the detachable assembly of the baffle part 501 and the baffle 5. The main body sidewall of the baffle 5 away from the heat exchange tube 4 has a slot 504, and the swing plug 7 is fixedly installed inside the slot 504.

[0032] The insertion structure of slot 502 and insert 503 enables the detachable installation of the baffle 501, facilitating the individual disassembly, replacement, cleaning, and maintenance of worn or clogged baffles 501 without requiring the complete replacement of the baffle vanes 5. This reduces equipment operation and maintenance costs and difficulty, and improves equipment maintenance efficiency. Simultaneously, the swing insert 7 installed in slot 504 can autonomously shake and vibrate due to airflow impact force when the flue gas flow velocity fluctuates or changes inside the rectifier cavity 101. This mechanical vibration removes flue gas dust, condensed impurities, and desulfurization residues adsorbed on the surface of the baffle vanes 5 in real time, reducing the decrease in heat exchange efficiency and obstructed airflow caused by ash and scale buildup on the surfaces of the baffle vanes 5 and heat exchange tubes 4. This achieves autonomous cleaning during equipment operation, ensuring the system maintains a long-term state of efficient heat exchange and stable rectification.

[0033] In a specific embodiment, the rectifier 8 consists of several regularly arranged baffle columns 801. Each baffle column 801 has two baffle plates 802 mounted on its outer side via a hinged structure. An elastic element 803 is fixedly connected between the relatively inner sides of the two baffle plates 802, continuously providing an elastic pulling force to bring the two baffle plates 802 closer together. Under the impact of the flue gas flow, the two baffle plates 802 can swing autonomously around the baffle column 801. After the swing stabilizes, the included angle between the two baffle plates 802 is controlled within the range of 90 degrees to 150 degrees.

[0034] A rectifier 8, composed of multiple sets of baffle columns 801 and oscillating baffle plates 802, can perform multi-stage diversion, rectification, and flow stabilization of the flue gas entering the desulfurization tower 2, dispersing the concentrated flue gas flow, eliminating flue gas deviation and pulsed airflow phenomena, and making the flue gas distribution entering the desulfurization tower 2 more uniform. The elastic element 803 can adaptively adjust the oscillation angle of the baffle plates 802 according to the flue gas flow pressure. When the flue gas velocity and pressure are high, the included angle of the baffle plates 802 increases adaptively, reducing the flue gas flow area and avoiding a sudden increase in desulfurization system pressure caused by a sudden increase in airflow pressure. After the pressure difference on both sides decreases, the included angle of the baffle plates 802 increases, gradually increasing the flue gas flow area. When the flue gas velocity and pressure are low, the elastic element 803 pulls the baffle plates 802 to retract, ensuring the amount of flue gas in the flue gas desulfurization tower while ensuring the turbulence rectification effect, adapting to the flue gas conditions under different boiler loads. The swing angle range of 90 to 150 degrees is suitable for the conventional flue gas parameters of coal-fired boilers, ensuring efficient rectification and flow stabilization while providing a stable airflow basis for the efficient desulfurization reaction inside the desulfurization tower 2.

[0035] As a specific embodiment, a pressure relief hole 804 is provided at the root position of the baffle plate 802. The pressure relief hole 804 is arranged through the entire length of the baffle plate 802, and the diameter of the pressure relief hole 804 is smaller than the thickness of the baffle plate 802 itself.

[0036] An elongated pressure relief hole 804 is provided at the root of the baffle plate 802. This allows for localized airflow pressure relief when the baffle plate 802 is subjected to flue gas impact and oscillation, alleviating the problem of airflow pressure concentration at the root of the baffle plate 802. This prevents deformation, breakage, and wear at the hinge points caused by excessive stress at the root, thus improving the structural strength and operational durability of the rectifier 8. Simultaneously, the pressure relief hole 804, arranged along the length direction, can evenly distribute the high-pressure airflow on the surface of the baffle plate 802, weakening the localized scouring effect of the airflow on the baffle plate 802 and reducing the wear rate of the equipment. The structural design of the pressure relief hole 804 being narrower than the thickness of the baffle plate 802 ensures the overall structural rigidity of the baffle plate 802 while achieving pressure relief and drag reduction. It prevents a decrease in structural strength due to the opening, and also avoids the rectification effect failure caused by an excessively large opening.

[0037] As a specific embodiment, it also includes a liquid storage tank 9. The flow-gathering tank 301 arranged on the inner wall of the condensation cooling tower 3 is connected to the inside of the desulfurization tower 2 through the liquid storage tank 9. The liquid storage tank 9 is mainly used for centralized storage, buffering and preparation of desulfurization solution, and at the same time, it receives the condensate collected by the flow-gathering tank 301, realizing the unified storage and circulation of solution and condensate. In this embodiment, the flow-gathering tank 301 adopts a spiral groove structure, which has the structural advantages of continuous flow guidance and flow gathering compared with the conventional straight groove structure. Several heat exchange tubes 4 arranged inside the condensation cooling tower 3 are arranged in a regular manner along the edge of the flow-gathering tank 301 to ensure that the layout of the heat exchange structure and the flow-gathering liquid guiding structure are compatible. The lower end of the baffle 5 mounted on the outside of each heat exchange tube 4 extends into the inside of the flow-gathering tank 301, which can cooperate with the fluid in the tank. The lower section of the flow collection tank 301 is integrally formed with an extension 302. The extension 302 extends towards the central axis of the desulfurization tower 2 to change the direction of liquid reflux.

[0038] By adding a storage tank 9 to establish an independent chemical buffer and circulation transfer structure, the traditional desulfurization system's direct chemical return and unbuffered mode is changed. This balances the supply and demand of chemical solutions in the system, avoiding drastic fluctuations in the liquid level inside the desulfurization tower 2, and preventing local enrichment or deficiency of chemical solutions, thus ensuring the continuous and stable operation of the desulfurization reaction inside the tower. The spiral-structured flow-collecting tank 301, relying on the guiding characteristics of the spiral curved surface, continuously and comprehensively collects the flue gas condensate and trace chemical droplets condensed on the inner wall of the condensation cooling tower 3, improving the condensate collection efficiency, reducing residual liquid adhesion to the tower wall, and avoiding the problems of long-term residual liquid retention leading to scaling and corrosion of the tower body. The heat exchange tubes 4 are arranged along the edge of the flow-collecting tank 301, and the baffle fins 5 extend into the flow-collecting tank 301. The baffle fins 5 perform secondary turbulent heat exchange on the flue gas above the tank opening, improving the low-temperature waste heat recovery efficiency while guiding the falling droplets to prevent droplet splashing and airflow turbulence. The extension 302, which extends from the lower section of the flow-collecting tank 301 towards the center of the desulfurization tower 2, can solve the problem of inconvenient collection of liquid dripping from the edge of the baffle 5, improve the recovery rate of desulfurization liquid, and reduce the cost of chemical consumption.

[0039] As a specific embodiment, the surface of the baffle 5 is provided with a guide groove 505, the guiding direction of the guide groove 505 is consistent with the length direction of the baffle 5, and a number of guide grooves 505 are provided on the surface of a single baffle 5 evenly arranged along its width direction. A flow-guiding groove 506 is provided inside the guide groove 505, and a number of branch grooves 507 are provided on the groove body of the flow-guiding groove 506. The branch grooves 507 extend laterally from the flow-guiding groove 506 to both sides perpendicular to the flow-guiding groove 506, and a liquid-gathering groove 508 is provided at the bottom of the groove body of each branch groove 507.

[0040] By arranging multiple sets of guide channels 505, diversion channels 506, and support channels 507 on the surface of the baffle 5, the condensate and residual chemicals generated during heat exchange on the surface of the baffle 5 can be comprehensively collected, preventing liquid from accumulating and forming scale on the surface of the baffle 5 and heat exchange tube 4, ensuring the cleanliness of the heat exchange structure surface, and continuously maintaining high-efficiency heat exchange performance. The crisscrossing diversion channels 506 and support channels 507 form a mesh-like liquid guiding structure, improving the liquid collection coverage. The liquid collection tank 508 at the bottom can concentrate the dispersed collected liquid, allowing the liquid to flow quickly and stably into the collection tank 301, avoiding turbulent airflow and localized liquid accumulation problems caused by liquid stagnation and dripping, and reducing the frequency of equipment maintenance.

[0041] In a specific embodiment, several layers of sprayers 202 arranged vertically are fixedly installed inside the desulfurization tower 2. Each layer of sprayers 202 is equipped with several liquid delivery pipes 203. Two liquid delivery plates 204 are fixedly installed at the output end of the liquid delivery pipes 203, and the two liquid delivery plates 204 are symmetrically arranged at a 120-degree angle. Several liquid outlets 205 are evenly opened on the surface of the liquid delivery plates 204, and the liquid outlets 205 of the two liquid delivery plates 204 are arranged in a opposite manner.

[0042] The desulfurization tower 2 utilizes a multi-layer spray system 202 to achieve layered spray desulfurization within the tower, extending the contact reaction time between the flue gas and the desulfurization spray liquid. Two liquid delivery plates 204, positioned at a 120-degree angle, form a large fan-shaped spray area, expanding the spray coverage and eliminating spray gaps within the desulfurization tower 2, preventing flue gas short-circuiting and escape. The oppositely positioned liquid outlets 205 allow the spray liquids on both sides to collide and blend, forming a dense and uniform spray liquid mist layer, increasing the contact probability and contact area between the flue gas and the spray liquid. Simultaneously, the liquid delivery plates 204 physically intercept the rising flue gas, slowing its upward flow velocity and forcing it to remain within the spray reaction area, allowing SO2 to fully neutralize with the desulfurization liquid, improving SO2 removal efficiency, and reducing SO2 emission concentration. The multi-layer structure is adaptable to high-concentration, high-flow-rate flue gas desulfurization conditions, resulting in enhanced system adaptability.

[0043] As a specific embodiment, the width of the liquid delivery plate 204 in the sprayer 202 is greater than the diameter of the liquid delivery pipe 203.

[0044] By limiting the width of the liquid delivery plate 204 to be greater than the diameter of the liquid delivery pipe 203, the liquid delivery plate 204 forms an outward-expanding spray interception structure. Compared with the traditional pipe diameter-matched spray plate structure, this expands the flue gas interception range and spray coverage radius, eliminates spray dead zones around the liquid delivery pipe 203, and achieves all-round spray coverage of the internal cross-section of the desulfurization tower 2. The widened liquid delivery plate 204 can improve the flue gas interception effect, extend the residence time of flue gas in the desulfurization reaction zone, and enhance the desulfurization reaction effect. At the same time, the larger plate area can accommodate more liquid outlets 205, increasing the atomization flow rate and uniformity of the spray liquid, adapting to the desulfurization requirements of large-flow flue gas, improving the overall desulfurization load and desulfurization efficiency of the system, and ensuring the stability of flue gas desulfurization under different operating conditions.

[0045] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of protection of the claims of the present invention.

Claims

1. A system for SO2 removal and low-temperature waste heat recovery from flue gas of a coal-fired boiler, characterized in that, include: A rectifier tower (1) has a rectifier cavity (101) and an outlet (102). The desulfurization tower (2) has an air inlet (201) at the bottom, the air inlet (201) is connected to the outlet (102), and a rectifier (8) is provided at the air inlet (201). The flue gas outlet of the desulfurization tower (2) is connected to the flue gas inlet of the condensing cooling tower (3). The inner wall of the condensing cooling tower (3) has a flow-gathering groove (301), which is connected to the desulfurization tower (2) through a pipeline. Heat exchange tube (4), there are several heat exchange tubes (4), which are evenly distributed in the rectifier cavity (101) and the condensation cooling tower (3). The heat exchange tube (4) has baffles (5), there are two baffles (5), which are set at a 120-degree angle to the direction of airflow. A condensation grid (6) is disposed inside the condensation cooling tower (3) and located above the heat exchange tube (4).

2. The SO2 removal and low-temperature waste heat recovery system for coal-fired boiler flue gas according to claim 1, characterized in that, The rectifier cavity (101) is a rectangular cavity. The heat exchange tubes (4) in the rectifier cavity (101) are in two groups. Each group of heat exchange tubes (4) consists of several rows. The adjacent rows of heat exchange tubes (4) are spaced apart to form an air gap (401). The two groups of heat exchange tubes (4) are arranged opposite to each other and cross each other. The heat exchange tubes (4) are inclined relative to the horizontal plane.

3. The SO2 removal and low-temperature waste heat recovery system for coal-fired boiler flue gas according to claim 1, characterized in that, The baffle (5) located in the rectifier cavity (101) has a baffle portion (501). There are several baffle portions (501), which are located on the side of the baffle (5) facing the airflow direction and are arranged perpendicular to the horizontal plane. They are used to increase the heat exchange area and disrupt the swirling flow on the outside of the baffle (5).

4. The SO2 removal and low-temperature waste heat recovery system for coal-fired boiler flue gas according to claim 3, characterized in that, The baffle (5) has a slot (502), and the slot (502) is arranged in a plurality of them. The baffle (501) has an insertion part (503), which is located in the slot (502). The baffle (5) has a slot (504) on the side away from the heat exchange tube (4). A swing plug (7) is provided in the slot (504). The swing plug (7) is used to swing with the change of airflow velocity in the rectifier cavity (101) to vibrate and clean the surface of the baffle (5).

5. The SO2 removal and low-temperature waste heat recovery system for coal-fired boiler flue gas according to claim 1, characterized in that, The rectifier (8) includes a plurality of baffle columns (801) arranged in a row. Two baffle plates (802) are oscillating on the baffle columns (801). The two baffle plates (802) are connected by an elastic element (803). The elastic element (803) is used to provide a force for the two baffle plates (802) to move closer to each other. The two baffle plates (802) oscillate under the action of airflow, and the included angle after oscillation is 90 degrees to 150 degrees.

6. The SO2 removal and low-temperature waste heat recovery system for coal-fired boiler flue gas according to claim 5, characterized in that, The root of the baffle plate (802) has a pressure relief hole (804), which is arranged along the length of the baffle plate (802), and the width of the pressure relief hole (804) is smaller than the thickness of the baffle plate (802).

7. The SO2 removal and low-temperature waste heat recovery system for coal-fired boiler flue gas according to claim 1, characterized in that, Also includes: The liquid storage tank (9) is connected to the desulfurization tower (2) through the liquid storage tank (9). The liquid storage tank (9) is used for storing desulfurization liquid. The flow-gathering tank (301) is a spiral groove. Several heat exchange tubes (4) are arranged along the edge of the flow-gathering tank (301). The baffles (5) of the heat exchange tubes (4) extend into the flow-gathering tank (301). The lower section of the flow-gathering tank (301) has an extension (302). The extension (302) extends toward the center of the desulfurization tower (2).

8. The SO2 removal and low-temperature waste heat recovery system for coal-fired boiler flue gas according to claim 7, characterized in that, The deflector vane (5) has a guide groove (505), the guide groove (505) is guided along the length direction of the deflector vane (5), each deflector vane (5) has a plurality of guide grooves (505) arranged along the width direction, the guide groove (505) has a diversion groove (506), the diversion groove (506) has a support groove (507), the support groove (507) extends from the diversion groove (506) to both sides perpendicular to the diversion groove (506), the bottom of the support groove (507) has a liquid collection groove (508), the liquid collection groove (508) is used to collect the condensate condensed at the diversion groove (506) and the support groove (507) and introduce it into the liquid collection groove (301).

9. A system for SO2 removal and low-temperature waste heat recovery from flue gas of a coal-fired boiler according to claim 1, characterized in that, The desulfurization tower (2) is equipped with several layers of sprayers (202). Each layer of sprayers (202) has several liquid delivery pipes (203). Each liquid delivery pipe (203) has a liquid delivery plate (204). There are two liquid delivery plates (204) set at a 120-degree angle. Each liquid delivery plate (204) has a liquid outlet (205) on its surface. The liquid outlets (205) of the two liquid delivery plates (204) are set opposite to each other. The liquid delivery plates (204) are used to intercept gas. The spray liquid sprayed through the liquid outlets (205) achieves efficient desulfurization.

10. A SO2 removal and low-temperature waste heat recovery system for flue gas from a coal-fired boiler according to claim 9, characterized in that, The width of the liquid delivery plate (204) is greater than the diameter of the liquid delivery pipe (203).

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