A heat exchange device and its heat exchange system

Abstract

The present application discloses a heat exchange device and its heat exchange system, belonging to the field of flue gas waste heat recovery, and solves the deficiency in the prior art that the variable-diameter flue is prone to damage when recovering the waste heat of dusty flue gas. The technical solution to solve this problem is mainly a heat exchange device, including a first heat exchanger and a second heat exchanger. The flue gas flows through the first heat exchanger and the second heat exchanger in sequence. The first heat exchanger and the second heat exchanger are connected by a variable-diameter flue. The large opening of the variable-diameter flue is connected to the outlet of the first heat exchanger, and the small opening is connected to the inlet of the second heat exchanger. A plurality of spaced baffle plates are arranged in the variable-diameter flue so that the baffle plates block part of the path of the dust hitting the side wall of the variable-diameter flue. The baffle plates are inclined to the flow direction of the flue gas to change the flow direction of the flue gas. The present application is mainly used to reduce the dust in the flue gas and extend the service life of the heat exchange device.

Description

Technical Field

[0001] The present application relates to the field of flue gas waste heat recovery, in particular to a heat exchange device and its heat exchange system. Background Art

[0002] A plate heat exchanger is a highly efficient heat exchange device. Its structure mainly consists of plate sheets, sealing gaskets, clamping bolts and pressure plates, and nozzles. The plate sheets are stamped from thin metal plates with various surface corrugations, which not only enhance the strength but also improve heat transfer; the sealing gaskets prevent fluid leakage; the clamping bolts and pressure plates ensure the tight connection of the plate sheets; the nozzles are used for the inlet and outlet of fluids. During operation, based on the principle of wall-type heat exchange, the hot and cold fluids flow on both sides of adjacent plate sheets, and heat is transferred through the plate sheets. Due to its corrugated structure, the fluid presents a complex flow state, greatly improving the heat exchange efficiency. Since the flue gas flowing in the heat exchanger is subjected to the resistance of the pipe wall friction, internal components, etc., the pressure gradually decreases, the driving force for pushing the flue gas to flow weakens, and the flow rate also decreases accordingly. When the flue gas exchanges heat in the heat exchanger, the temperature decreases. According to the ideal gas state equation (PV = nRT), when the pressure changes little, the decrease in temperature will cause the gas volume to decrease, while the mass flow rate remains unchanged. According to (v = Q / A) (where v is the flow rate, Q is the volume flow rate, and A is the pipe cross-sectional area), when the volume flow rate decreases, the flow rate will decrease. Therefore, the flow rate at the flue gas outlet will decrease.

[0003] When using a double heat exchanger for heat exchange, a variable-diameter flue is usually used to connect the two heat exchangers to ensure a certain speed in the downstream heat exchanger and a certain heat exchange efficiency. In the waste heat recovery of dusty flue gas, the dust in the flue gas will impact the inner wall of the variable-diameter flue when passing through it, forming local eddies of dust, severely wearing the inner wall of the variable-diameter flue. After long-term use, the flue will be damaged, and the phenomenon of flue side wall peeling will occur. These peeled substances will form larger particles together with the dust and enter the downstream heat exchanger, resulting in dust accumulation in the downstream heat exchanger and other situations affecting heat exchange. The existing technology is to reinforce the inner wall of the variable-diameter flue with a coating or high-strength material to extend the service life of the variable-diameter flue and the downstream heat exchanger, but this will increase the material cost of the equipment and increase the processing steps and processing difficulty. Summary of the Invention

[0004] In order to overcome the deficiency that the variable-diameter flue is easily damaged when the double heat exchanger is used for the waste heat recovery of dusty flue gas in the prior art, the present application provides a heat exchange device and its heat exchange system, which realizes reducing the direct impact of dust in the flue gas on the flue, thereby extending the service life of the heat exchange device.

[0005] To achieve the above object, the present application adopts the following technical solution: A heat exchange device includes a first heat exchanger and a second heat exchanger. Flue gas flows through the first heat exchanger and the second heat exchanger in sequence. The first heat exchanger and the second heat exchanger are connected by a reducing flue. The large opening of the reducing flue is connected to the outlet of the first heat exchanger, and the small opening is connected to the inlet of the second heat exchanger. A plurality of spaced guide plates are provided in the reducing flue to block the path of part of the soot hitting the side wall of the reducing flue, and the guide plates are inclined to the flow direction of the flue gas to change the flow direction of the flue gas.

[0006] After adopting the above technical solution, the present application has the following advantages: Since the reducing flue has a large opening and a small opening, at least one side wall is inclined to the flow direction of the flue gas, and this side wall will be directly hit by the dust in the flue gas. A plurality of spaced guide plates are arranged on the path of the soot hitting the reducing flue, greatly reducing the number of times the reducing flue is hit by the soot. And part of the soot will enter the space between two adjacent guide plates and collide. Due to the different inertial kinetic energies of the dust and the gas, after the soot particles collide with the guide plates, their speeds will be greatly reduced, and their kinetic energies are not enough to support them to continue flowing with the flue gas. Under the action of gravity, they will separate from the flue gas and settle to the bottom of the reducing flue, thus realizing the separation of part of the soot from the flue gas and achieving the effect of dust removal. And because a plurality of spaced guide plates are arranged in the reducing flue, the reducing flue can be divided into multiple channels for the flue gas to flow through, making the guiding effect of the flue gas better, so that the flue gas in the reducing flue can stably enter the downstream equipment along the guidance of the guide plates without many vortex phenomena, reducing the damage to the downstream equipment. If the guide plates are not designed, all the soot will hit the side wall of the reducing flue, causing damage to the inner wall of the reducing flue after long-term use, and seriously, the side wall will fall off and the dust removal effect cannot be achieved. And compared with the method of strengthening the inner wall of the reducing flue by coating or high-strength materials in the prior art, this solution does not need to use special coatings or high-strength materials, and only adding a small number of guide plates can extend the life of the equipment and achieve partial dust removal.

[0007] Further, the guide plates are arranged at intervals up and down and are inclined downward to the flow direction of the flue gas.

[0008] Adopting the foregoing technical solution, the guide plates are inclined downward, which is more conducive to the soot particles to accelerate sedimentation under the action of gravity while changing the flow direction of the flue gas. Since the direction of the gravity is consistent with the inclination direction of the guide plates, after the soot particles collide with the guide plates, in addition to losing kinetic energy due to their own inertia and collision, they will also sink to the bottom of the reducing flue faster under the additional action of gravity, thereby further improving the dust removal efficiency, separating more soot from the flue gas, and reducing the amount of soot entering the downstream heat exchanger.

[0009] Furthermore, an air flow distribution plate is provided in the variable-diameter flue downstream of the guide plate. The air flow distribution plate is provided with a plurality of outwardly bulging cavities, and the cavities include a first cavity and a second cavity. The volume of the first cavity closer to the downstream is smaller than the volume of the second cavity closer to the upstream.

[0010] With the foregoing technical solution, since the air flow distribution plate makes the flue gas flow more smoothly, reducing eddy currents and violent fluctuations of the air flow, the possibility of the dust that has already settled to the bottom of the flue being lifted by the air flow again is reduced, that is, the phenomenon of secondary dust emission is inhibited, which helps to keep the inside of the flue clean and improve the overall dust removal effect. When the flue gas passes through the cavities of the air flow distribution plate, the flow direction and speed are constantly changed, increasing the collision probability between the dust particles in the flue gas. According to the coagulation theory, the collision between particles will prompt them to coagulate into larger particles, and the large-particle dust is more likely to be separated from the flue gas due to the action of gravity, further improving the dust removal efficiency.

[0011] Furthermore, the cavities extend up and down to the edge of the air flow distribution plate, so that the dust particles in the flue gas settle along the outer surface of the cavities to the bottom of the variable-diameter flue.

[0012] With the foregoing technical solution, the cavities extend up and down to the edge of the air flow distribution plate, greatly increasing the path for the dust particles to contact and settle on the surface of the cavities. During the flow of the flue gas, the dust particles have more opportunities to collide or contact with the surface of the cavities. Once in contact, due to the action of gravity and the adhesion between the particles and the cavity surface, etc., it is easier to settle downward along the outer surface of the cavity to the bottom of the variable-diameter flue, thereby improving the dust removal efficiency and effectively reducing the amount of dust entering the downstream heat exchanger.

[0013] Furthermore, a pre-dust collector for reducing the flow velocity of the flue gas is provided upstream of the first heat exchanger.

[0014] With the foregoing technical solution, the flue gas usually contains a certain amount of particulate matters such as dust. The faster its flow velocity, the stronger the scouring and wear effect on the inner walls of equipment such as heat exchangers. After the pre-dust collector removes a certain amount of dust and reduces the flow velocity of the flue gas, the impact force of the remaining particulate matters such as dust in the flue gas on the first heat exchanger can be weakened, and the flow velocity of the flue gas entering the variable-diameter flue subsequently is reduced, protecting the side walls in the variable-diameter flue from high-speed impact, being able to extend the service life of the variable-diameter flue. Moreover, the pre-dust collector reduces the flow velocity of the flue gas, enabling the flue gas to flow more smoothly and orderly in the first heat exchanger, allowing the hot and cold fluids to perform more sufficient and stable heat exchange based on the principle of wall-type heat exchange, improving the heat exchange efficiency of the first heat exchanger, and also being able to prevent problems such as wear and corrosion of the heat exchanger caused by high-speed scouring of the flue gas, and being able to extend the service life of the heat exchanger.

[0015] Furthermore, the pre-dust collector is composed of a plurality of dust removal components staggeredly distributed along the flue gas, the dust removal components include an air inlet, a vortex portion and an air outlet, and the air inlet and the air outlet are arranged at the same place.

[0016] With the above technical solution, multiple vortex structures are staggered and distributed, so that the flue gas passes through multiple dust removal units in sequence, which is equivalent to multiple dust removal processes. Each time it passes, the dust can be further separated, which significantly improves the overall dust removal efficiency and ensures that the flue gas entering the downstream equipment is cleaner. The air inlet and the air outlet are set at the same place, so that the flue gas will collide with the subsequent flue gas when it flows out of the air outlet. On the one hand, the dust on each other is bonded into large particles and settled. On the other hand, the flow rate of the flue gas is reduced, so that some of the smoke dust is settled after lacking kinetic energy. On the other hand, when the dust-laden flue gas enters the vortex part, a strong vortex phenomenon will be generated, and the dust in the flue gas will be thrown to the periphery due to the action of centrifugal force and separated from the gas, so as to achieve efficient dust removal.

[0017] Furthermore, the dust removal component is composed of two dust removal cylinders in mirror image, and the dust removal cylinder includes a radius of The first arc cylinder and the radius are The first arc tube and the second arc tube both have openings, one end of the first arc tube faces the direction of smoke inflow, and the other end is connected to one end of the second arc tube, and the other end of the second arc tube faces away from the direction of smoke inflow, wherein There is a gap between one end of the first arc tube facing the smoke and one end of the second arc tube facing away from the smoke, so that the smoke can enter the first arc tube and the second arc tube.

[0018] Using the above technical solution, the radius of the first arc tube Greater than the radius of the second arc tube This size difference, combined with the opening design, allows the flue gas to form a special vortex shape in the tube after entering. When the dust-laden flue gas enters from the first arc tube toward one end of the flue gas and flows in the space formed by the two arc tubes, a strong centrifugal force will be generated due to the change in radius and the guidance of the space shape. Dust particles are more easily thrown to the tube wall under the action of centrifugal force and separated from the gas, thereby improving the dust removal efficiency of a single dust removal tube. The mirror image composition of the two dust removal tubes further enhances this dust removal effect.

[0019] Furthermore, the central angle of the opening of the first arc-shaped tube is 60° to 180°, and the central angle of the opening of the second arc-shaped tube is 180° to 270°.

[0020] With the foregoing technical solution, different ranges of the opening central angles enable the dust removal component to be adjusted according to actual working conditions such as flue gas flow rate, dust content, and flow velocity. For flue gas with a high dust content and large flow rate, a larger opening central angle can be selected to improve the treatment capacity; for working conditions with extremely high requirements for dust removal efficiency, a suitable smaller opening central angle can be selected to strengthen the centrifugal separation effect, enhancing the adaptability of the equipment to different working conditions.

[0021] Further, a hopper with a lock hopper is provided under the pre-dust collector and / or the variable-diameter flue.

[0022] With the foregoing technical solution, when it is necessary to clean the dust, it can be discharged through the outlet of the hopper. The design of the lock hopper enables that when discharging the dust, the air flow state in the system will not be affected, and it is not necessary to completely interrupt the operation of the system, facilitating the cleaning operation of the maintenance personnel and reducing the maintenance workload and difficulty.

[0023] A heat exchange system includes the foregoing heat exchange equipment. The water inlet of the second heat exchanger is connected to the water tank, the water outlet of the second heat exchanger is connected to the water inlet of the first heat exchanger, and the water after heat exchange in the first heat exchanger flows out from the water outlet of the first heat exchanger.

[0024] With the foregoing technical solution, the second heat exchanger first preliminarily heats the water in the water tank, and the heated water then flows into the first heat exchanger to perform secondary heat exchange with the flue gas in the first heat exchanger. Through this two-stage heat exchange method, the heat in the flue gas is fully utilized, the thermal efficiency of the entire system is improved, and the maximum utilization of energy is achieved. Since the flue gas temperature of the second heat exchanger is relatively low, and the temperature of the medium flowing into the second heat exchanger is also relatively low, the temperature difference between the two is small, which can prevent the phenomenon of flue gas side condensation when the relatively low-temperature medium exchanges heat with the relatively high-temperature flue gas, and the heated medium flowing out of the second heat exchanger is used to increase the temperature of the medium exchanging heat with the flue gas in the first heat exchanger. In this way, when exchanging heat with the flue gas in the first heat exchanger, the temperature difference between the two is also relatively small, which can avoid excessive reduction of the flue gas temperature in the first heat exchanger and keep its temperature above the dew point temperature, thereby effectively reducing the flue gas side condensation phenomenon. Condensation will cause problems such as corrosion and blockage, and reducing condensation can protect the equipment and extend the service life of the equipment. Brief Description of the Drawings

[0025] The following further illustrates the present application with reference to the drawings:

[0026] Figure 1 It is a schematic diagram of a heat exchange equipment and its heat exchange system of the present application;

[0027] Figure 2 It is a schematic diagram of the variable-diameter flue;

[0028] Figure 3is Figure 2 Top view of the air flow distribution plate in

[0029] Figure 4 Top view of the pre - dust collector;

[0030] Figure 5 Enlarged view of the dust removal component;

[0031] Figure 6 Structural diagram of the dust removal cylinder;

[0032] Figure 7 Schematic diagram of another embodiment of the heat exchange system;

[0033] Description of the drawings: 1. First heat exchanger; 2. Second heat exchanger; 3. Reducing flue; 31. Deflector; 32. Air flow distribution plate; 33. Cavity; 331. First cavity; 332. Second cavity; 4. Pre - dust collector; 41. Ash hopper; 5. Dust removal component; 51. Air inlet; 52. Eddy current part; 53. Air outlet; 6. Dust removal cylinder; 61. First arc - shaped cylinder; 62. Second arc - shaped cylinder; 7. Water tank; 71. Water pump; 72. Refrigerant inlet header; 73. Refrigerant outlet header; 74. Inlet valve; 75. Outlet valve; 76. Electrostatic precipitator; 77. De - oxygenator; 8. Water - water heat exchanger; 81. Area to be heated; 82. Circulation area; 83. Circulation water pump; 9. Flue. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the embodiments of this application clearer, the following will, with reference to the drawings in the embodiments of this application, clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only some, but not all, of the embodiments of this application.

[0035] The terms "first", "second", etc. (if any) in the description and claims of this application are used to distinguish similar objects, rather than to describe a specific order or sequence. Even if "second" is used to distinguish a certain technical feature, it does not necessarily imply the existence of "first". It should be understood that in this application, "including" and "having" and any of their variations are intended to cover non - exclusive inclusion. It should be understood that in this application, "a plurality of" means two or more. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, X and / or Y can represent: X exists alone, X and Y exist simultaneously, and Y exists alone. The character " / " generally represents an "or" relationship between the related objects before and after. "Including X, Y, and Z", "including X, Y, Z" means that all of X, Y, and Z are included, "including X, Y, or Z" means that one of X, Y, and Z is included, and "including X, Y, and / or Z" means that any one or any two or all three of X, Y, and Z are included.

[0036] The technical solution of the present application will be described in detail below with specific embodiments. These several specific embodiments can be combined or replaced according to the actual situation. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0037] As Figures 1 to 7 shown, the present application provides a heat exchange device, including a first heat exchanger 1 and a second heat exchanger 2. Flue gas flows through the first heat exchanger 1 and the second heat exchanger 2 in sequence. The first heat exchanger 1 and the second heat exchanger 2 are connected by a reducing flue 3. The large opening of the reducing flue 3 is connected to the outlet of the first heat exchanger 1, and the small opening is connected to the inlet of the second heat exchanger 2. A plurality of spaced baffle plates 31 are provided in the reducing flue 3 to block the path of part of the soot hitting the side wall of the reducing flue 3. The baffle plates 31 are inclined to the flow direction of the flue gas to change the flow direction of the flue gas.

[0038] After adopting the above technical solution, the present application has the following advantages: Since the reducing flue 3 has a large opening and a small opening, at least one side wall is inclined to the flow direction of the flue gas, and this side wall will be directly hit by the dust in the flue gas. A plurality of spaced baffle plates 31 are provided on the path where the soot hits the reducing flue 3, which greatly reduces the number of times the reducing flue 3 is hit by the soot. And part of the soot will enter the space between two adjacent baffle plates 31 for collision. Due to the different inertial kinetic energies of the dust and the gas, after the soot particles collide with the baffle plates 31, their speeds will be greatly reduced, and their kinetic energies are not enough to support them to continue flowing with the flue gas. Under the action of gravity, they will separate from the flue gas and settle to the bottom of the reducing flue 3, thus realizing the separation of part of the soot from the flue gas and achieving the effect of dust removal. And because a plurality of spaced baffle plates 31 are provided in the reducing flue 3, the reducing flue 3 can be divided into multiple channels for the flue gas to flow through, making the guiding effect of the flue gas better, so that the flue gas in the reducing flue 3 can stably enter the downstream equipment along the guidance of the baffle plates 31 without many vortex phenomena, reducing the damage to the downstream equipment. If the baffle plates 31 are not designed, all the soot will hit the side wall of the reducing flue 3, resulting in damage to the inner wall of the reducing flue 3 after long-term use, and in severe cases, the side wall will fall off, and the effect of dust removal cannot be achieved. And compared with the method of strengthening the inner wall of the reducing flue 3 by coating or high-strength materials in the prior art, this solution does not require the use of special coatings or high-strength materials, and only adding a small number of baffle plates 31 can extend the life of the equipment and achieve partial dust removal.

[0039] Preferably, as Figure 2As shown, the height direction of the first heat exchanger 1 is divided into seven equal parts, and the height direction of the second heat exchanger 2 is divided into the same seven equal parts. The guide plates 31 are distributed on the straight lines connecting the corresponding equal points on the left and right sides. The connecting line formed by the ends of all the guide plates 31 forms an angle of 30° - 75° with the horizontal, preferably 40° - 60°.

[0040] It can be understood that this solution is a flue gas improvement measure between two heat exchangers, and can also be used for the flue gas improvement solution between every two heat exchangers in a heat exchanger system with multiple heat exchangers. The guide plates 31 can be fixedly connected to the reduced-diameter flue 3 by means such as welding, or connected to the reduced-diameter flue 3 by detachable connection means such as bolt connection.

[0041] Furthermore, the guide plates 31 are arranged at intervals up and down and are inclined downward in the direction of flue gas flow.

[0042] Adopting the foregoing technical solution, the guide plates 31 are inclined downward, which makes it more conducive to the accelerated settlement of dust particles under the action of gravity while changing the direction of flue gas flow. Since the direction of the action of gravity is consistent with the inclination direction of the guide plates 31, after the dust particles collide with the guide plates 31, in addition to losing kinetic energy due to their own inertia and collision, they will also settle faster to the bottom of the reduced-diameter flue 3 under the additional action of gravity, thereby further improving the dust removal efficiency, separating more dust from the flue gas, and reducing the amount of dust entering the downstream heat exchanger.

[0043] Furthermore, an air flow distribution plate 32 is provided in the reduced-diameter flue 3 downstream of the guide plates 31. The air flow distribution plate 32 is provided with a plurality of outward-bulging cavities 33. The cavities 33 include a first cavity 331 and a second cavity 332, as Figure 3 shown, the volume of the first cavity 331 closer to the downstream is smaller than the volume of the second cavity 332 closer to the upstream.

[0044] Adopting the foregoing technical solution, since the air flow distribution plate 32 makes the flue gas flow more smoothly, reducing eddies and violent fluctuations of the air flow, the possibility of the dust that has already settled to the bottom of the reduced-diameter flue 3 being lifted up again by the air flow is reduced, that is, the phenomenon of secondary dust emission is inhibited, which helps to keep the inside of the reduced-diameter flue 3 clean and improve the overall dust removal effect. When the flue gas passes through the cavities 33 of the air flow distribution plate 32, the flow direction and speed are constantly changed, increasing the collision probability between the dust particles in the flue gas. According to the coagulation theory, the collision between particles will prompt them to coagulate into larger particles, and the large-particle dust is more likely to be separated from the flue gas due to the action of gravity, further improving the dust removal efficiency.

[0045] Specifically, the air flow distribution plate 32 is formed by mechanically pressing or laser welding two metal steel plates with a thickness of 1.5 - 2.5 mm to form double-sided convex drums, which are hollow and in a cavity shape. The height of adjacent convex drums decreases along the air flow direction, asFigure 3 As shown, the height of the second cavity in the upstream is h1, and the height of the first cavity in the downstream is h2, and the ratio is 1.1 - 1.5, preferably 1.3; the length of the cavity 33 decreases successively along the gas flow direction, such as Figure 3 As shown, the length of the second cavity 332 in the upstream is L1, and the length of the first cavity 331 in the downstream is L2, and the ratio is 1.1 - 1.5, preferably 1.3; the distance between adjacent cavities 33 is the average value of the lengths of the left and right cavities 33 along the flue gas flow direction, such as Figure 3 L3 in

[0046] Furthermore, the cavity 33 extends up and down to the edge of the gas flow distribution plate 32, so that the dust particles in the flue gas settle to the bottom of the reduced-diameter flue 3 along the outer surface of the cavity 33.

[0047] Adopting the foregoing technical solution, the cavity 33 extends up and down to the edge of the gas flow distribution plate 32, greatly increasing the path for dust particles to contact and settle on the surface of the cavity 33. During the flow of the flue gas, the dust particles have more opportunities to collide or contact with the surface of the cavity 33. Once in contact, due to the action of gravity and the adhesion force between the particles and the surface of the cavity 33, etc., it is easier to settle downward along the outer surface of the cavity 33 to the bottom of the reduced-diameter flue 3, thereby improving the dust removal efficiency and effectively reducing the amount of dust entering the downstream heat exchanger.

[0048] Furthermore, a pre-dust collector 4 for reducing the gas flow velocity is provided upstream of the first heat exchanger 1.

[0049] Adopting the foregoing technical solution, the flue gas usually contains a certain amount of particulate matters such as dust. The faster its flow velocity, the stronger the scouring and abrasion effect on the inner walls of equipment such as heat exchangers. After the pre-dust collector 4 removes a certain amount of dust and reduces the gas flow velocity, the impact force of the remaining dust and other particulate matters in the flue gas on the first heat exchanger 1 can be weakened, and the gas flow velocity of the flue gas entering the reduced-diameter flue 3 subsequently can be reduced, protecting the side wall in the reduced-diameter flue 3 from being impacted at high speed, being able to extend the service life of the reduced-diameter flue 3, and the pre-dust collector 4 reducing the gas flow velocity can make the flow of the flue gas in the first heat exchanger 1 more stable and orderly, enabling more sufficient and stable heat exchange between the cold and hot fluids based on the principle of wall heat transfer, improving the heat exchange efficiency of the first heat exchanger 1, and also being able to prevent problems such as wear and corrosion of the heat exchanger caused by high-speed scouring of the flue gas, and being able to extend the service life of the heat exchanger.

[0050] Furthermore, the pre-dust collector 4 is composed of a plurality of dust removal members 5 distributed alternately along the flue gas. The dust removal member 5 includes an air inlet 51, a vortex part 52, and an air outlet 53, and the air inlet 51 and the air outlet 53 are arranged at the same place.

[0051] Adopting the foregoing technical solution, multiple vortex structures are staggered and distributed, enabling the flue gas to pass through multiple dust removal units in sequence, which is equivalent to carrying out multiple dust removal processes. Each passage can further separate dust, significantly improving the overall dust removal efficiency and ensuring that the flue gas entering the downstream equipment is cleaner. The air inlet 51 and the air outlet 53 are arranged at the same location, causing the flue gas flowing out from the air outlet 53 to collide with the subsequent incoming flue gas. On the one hand, the mutual dust adheres to form large particles and settles; on the other hand, the flow rate of the flue gas is reduced, causing some dust particles to settle due to lack of kinetic energy. On the other hand, when the dusty flue gas enters the eddy current part 52, a strong eddy current phenomenon will occur, and the dust in the flue gas will be thrown to the periphery due to the action of centrifugal force and separated from the gas, achieving efficient dust removal.

[0052] Specifically, there is a gap of about 30 mm to 50 mm between the top ends of all dust removal components 5 and the top wall of the flue 9. The bottom ends of all dust removal components 5 are flush with the upper horizontal line of the ash hopper 41. A gas seal baffle for preventing flue gas short-circuit is provided below each row of dust removal components 5. The gas seal baffle extends into the ash hopper 41, and there is an ash falling channel between the end of the baffle and the wall of the ash hopper 41. The upper part of the gas seal baffle overlaps with the dust removal component 5 by 200 mm to prevent flue gas short-circuit. All the dust removal components 5 are made of wear-resistant metal, such as 16Mn plate.

[0053] Furthermore, the dust removal component 5 is composed of two dust removal cylinders 6 mirror-imaged. The dust removal cylinder 6 includes a first arc cylinder 61 with a radius of and a second arc cylinder 62 with a radius of . Both the first arc cylinder 61 and the second arc cylinder 62 have openings. One end of the first arc cylinder 61 faces the flue gas inflow direction, and the other end is connected to one end of the second arc cylinder 62. The other end of the second arc cylinder 62 faces away from the flue gas inflow direction, where . There is a gap between the end of the first arc cylinder 61 facing the flue gas and the end of the second arc cylinder 62 facing away from the flue gas, so that the flue gas can enter the first arc cylinder 61 and the second arc cylinder 62.

[0054] Adopting the foregoing technical solution, the radius of the first arc cylinder 61 is greater than the radius of the second arc cylinder 62. This size difference, combined with the opening design, causes a special eddy current form to be formed inside the cylinder after the flue gas enters. When the dusty flue gas enters from the end of the first arc cylinder 61 facing the flue gas and flows in the space formed by the two arc cylinders, due to the guidance of the radius change and the space shape, a strong centrifugal force will be generated. The dust particles are more likely to be thrown to the cylinder wall under the action of centrifugal force and separated from the gas, thereby improving the dust removal efficiency of a single dust removal cylinder 6. The mirror imaging of the two dust removal cylinders 6 further enhances this dust removal effect.

[0055] Specifically, such as Figure 4As shown, the dust removal components 5 are arranged uniformly in the cross-section perpendicular to the flue gas flow direction. The first row is arranged with the dust removal components 5 each composed of two dust removal cylinders 6. The number of dust removal components 5 in the second row is one less than that in the previous row, and one dust removal cylinder 6 is arranged between each of them and the front and rear side walls of the flue 9 respectively. The rest are arranged alternately in sequence. The distance between adjacent dust removal components 5 in each row is the same, so that the flow velocity of the dust-containing flue gas passing through this gap is between 10 and 20 m / s, preferably 13 to 18 m / s. The center line of the gap formed by the outer edges of the front dust removal components 5 and the outer edges of the adjacent dust removal components 5 is aligned with the center line of the next row of eddy current components along the flue gas flow direction. Adjacent two rows of dust removal components 5 are arranged in a regularly staggered manner.

[0056] Preferably, .

[0057] Furthermore, the central angle of the opening of the first arc-shaped cylinder 61 is 60° to 180°, and the central angle of the opening of the second arc-shaped cylinder 62 is 180° to 270°.

[0058] With the foregoing technical solution, different ranges of the opening central angle enable the dust removal component 5 to be adjusted according to actual working conditions such as the flue gas flow rate, dust content, and flow velocity. For flue gas with a high dust content and large flow rate, a larger opening central angle can be selected to improve the treatment capacity; for working conditions with extremely high requirements for dust removal efficiency, a suitable smaller opening central angle can be selected to strengthen the centrifugal separation effect, enhancing the adaptability of the equipment to different working conditions.

[0059] Preferably, the opening central angle of the first arc-shaped cylinder 61 is 135°, and the opening central angle of the second arc-shaped cylinder 62 is 270°.

[0060] Furthermore, a hopper 41 with a lock gas device is provided below the pre-dust collector 4 and / or the variable-diameter flue 3.

[0061] With the foregoing technical solution, when it is necessary to clean the dust, it can be discharged through the outlet of the hopper 41. The design of the lock gas device enables the dust to be discharged without affecting the air flow state in the system and without completely interrupting the system operation, facilitating the cleaning operation of the maintenance personnel and reducing the maintenance workload and difficulty.

[0062] A heat exchange system includes the above-mentioned heat exchange equipment. The water inlet of the second heat exchanger 2 is connected to the water tank 7, the water outlet of the second heat exchanger 2 is connected to the water inlet of the first heat exchanger 1, and the water after heat exchange in the first heat exchanger 1 flows out from the water outlet of the first heat exchanger 1.

[0063] Adopting the foregoing technical solution, the second heat exchanger 2 first preliminarily heats the water in the water tank 7, and the heated water then flows into the first heat exchanger 1 to perform secondary heat exchange with the flue gas in the first heat exchanger 1. Through this two-stage heat exchange method, the heat in the flue gas is fully utilized, the thermal efficiency of the entire system is improved, and the maximum utilization of energy is achieved. Since the flue gas temperature of the second heat exchanger 2 is relatively low, and the temperature of the medium flowing into the second heat exchanger 2 is also relatively low, the temperature difference between the two is small, which can prevent the phenomenon of flue gas side condensation when the relatively low-temperature medium exchanges heat with the relatively high-temperature flue gas, and the heated medium flowing out of the second heat exchanger 2 is used to increase the temperature of the medium exchanging heat with the flue gas in the first heat exchanger 1. In this way, when exchanging heat with the flue gas in the first heat exchanger 1, the temperature difference between the two is also relatively small, which can avoid excessive reduction of the flue gas temperature in the first heat exchanger 1 and keep its temperature above the dew point temperature, thereby effectively reducing the flue gas side condensation phenomenon. Condensation will cause problems such as corrosion and blockage. Reducing condensation can protect the equipment and extend the service life of the equipment.

[0064] Specifically, the outlet of the water tank 7 is connected to the inlet of the water pump 71, the outlet of the water pump 71 is connected to the water inlet of the second heat exchanger 2, and the water outlet of the first heat exchanger 1 is connected to the deaerator. A plate wear-resistant sticker is provided in front of the plate heat exchange fins in each stage of the heat exchanger. Each stage of the heat exchanger is provided with a refrigerant inlet header 72 and a refrigerant outlet header 73, and corresponding inlet valves 74 and outlet valves 75 are provided.

[0065] Preferably, a plurality of heat exchange plates are arranged along the flue gas flow direction in the heat exchanger, or several heat exchange modules composed of a plurality of heat exchange plates are arranged. The heat exchange plates are formed by laser welding and bulging of metal thin plates. The double surfaces of the heat exchange plates are wavy. The "dirty" medium flows between the plates, and the "clean" medium flows inside the plates. The center distance between two adjacent heat exchange plates is 20 mm to 50 mm. The arrangement direction of the heat exchange plates is the same as the flue gas flow direction. The heat exchange plate material is ND steel, stainless steel, nickel-based alloy, etc., with a thickness of 0.5 mm to 3.0 mm, preferably 1.0 mm to 2.5 mm. When necessary, an organic resin coating or inorganic coating with good thermal conductivity, heat resistance, wear resistance, and adhesion to the metal is sprayed / brushed on the metal surface. The recommended thickness of the coating is 60 to 300 preferably 100 to 250 .

[0066] It can be understood that several stages of heat exchangers can be arranged in sequence along the flue gas flow direction, and the heat exchange plates in adjacent heat exchangers are arranged in a staggered manner.

[0067] Such as Figure 1As shown, after the flue gas enters the flue 9, it first enters the pre-dust collector 4 for pre-dust removal, then enters the first heat exchanger 1 for the first heat exchange, and then enters the variable-diameter flue 3 to accelerate the flow rate of the flue gas to a certain extent and perform dust removal to a certain degree. Then it enters the second heat exchanger 2 for the second heat exchange, and finally enters the electrostatic precipitator 76 for dust removal and then is discharged.

[0068] The liquid to be heated is pumped from the water tank 7 by the water pump 71 into the second heat exchanger 2 for preliminary heating, then enters the first heat exchanger 1 for reheating, and finally is introduced into the deaerator 77.

[0069] It can be understood that in another embodiment, as Figure 7 shown, the liquid to be heated is pumped from the water tank 7 by the water pump 71 into the area 81 to be heated of the water-water heat exchanger 8. The outlet of the area 81 to be heated is connected to the deaerator 77. The liquid in the circulation area 82 is connected to the second heat exchanger 2 by the circulation water pump 83 for preliminary heating, then enters the first heat exchanger 1 for reheating, and finally is connected to the inlet of the circulation area 82.

[0070] In addition to the above preferred embodiments, there are other implementation manners for this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope claimed in this application.

Claims

1. A heat exchange device, characterized in that, It includes a first heat exchanger and a second heat exchanger. The flue gas flows through the first heat exchanger and the second heat exchanger in sequence. The first heat exchanger and the second heat exchanger are connected by a reduced-diameter flue. The large opening of the reduced-diameter flue is connected to the outlet of the first heat exchanger, and the small opening is connected to the inlet of the second heat exchanger. A plurality of guide plates are arranged at intervals up and down in the reduced-diameter flue. The first heat exchanger and the second heat exchanger are divided into multiple equal points with the same number in the height direction. The guide plates are distributed on the straight lines connecting the corresponding equal points on the left and right sides. The guide plates are inclined downward with respect to the flow direction of the flue gas, and the connection line formed by the ends of all the guide plates forms an angle of 30°-75° with the horizontal. An air distribution plate is arranged downstream of the guide plates in the reduced-diameter flue. The air distribution plate is vertically arranged along the flow direction of the flue gas. The side of the guide plate close to the air distribution plate is arranged at an interval from the air distribution plate.

2. The heat exchange device according to claim 1, characterized in that The air distribution plate is provided with a plurality of cavities bulging outwards. The cavities include a first cavity and a second cavity. The volume of the first cavity closer to the downstream is smaller than the volume of the second cavity closer to the upstream.

3. The heat exchange device according to claim 2, characterized in that, The cavities extend up and down to the edges of the air distribution plate, so that the dust particles in the flue gas settle to the bottom of the reduced-diameter flue along the outer surface of the cavities.

4. A heat exchange device according to claim 1, characterized in that, A pre-dust collector for reducing the flow velocity of the flue gas is arranged upstream of the first heat exchanger.

5. An exchange heat device according to claim 4, characterized in that, The pre-dust collector is composed of a plurality of dust removal members distributed alternately along the flue gas. The dust removal member includes an air inlet, a vortex part, and an air outlet. The air inlet and the air outlet are arranged at the same place.

6. A heat exchange device according to claim 5, characterized in that, The dust removal member is composed of two dust removal cylinders mirror-imaged. The dust removal cylinder includes a first arc-shaped cylinder with a radius of r1 and a second arc-shaped cylinder with a radius of r2. Both the first arc-shaped cylinder and the second arc-shaped cylinder have openings. One end of the first arc-shaped cylinder faces the direction of the flue gas inflow, and the other end is connected to one end of the second arc-shaped cylinder. The other end of the second arc-shaped cylinder faces away from the direction of the flue gas inflow, where r1>r2. There is a gap between the end of the first arc-shaped cylinder facing the flue gas and the end of the second arc-shaped cylinder facing away from the flue gas, so that the flue gas enters the first arc-shaped cylinder and the second arc-shaped cylinder.

7. An exchange heat equipment according to claim 6, characterized in that, The central angle of the opening of the first arc-shaped cylinder is 60° to 180°, and the central angle of the opening of the second arc-shaped cylinder is 180° to 270°.

8. A heat exchange device according to claim 4, wherein A hopper with a lock hopper is arranged under the pre-dust collector and / or the reduced-diameter flue.

9. A heat exchange system, characterized in that, It includes a heat exchange device according to any one of claims 1 to 8. The water inlet of the second heat exchanger is connected to a water tank. The water outlet of the second heat exchanger is connected to the water inlet of the first heat exchanger. The water after heat exchange in the first heat exchanger flows out from the water outlet of the first heat exchanger.

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