Heat exchange equipment and heat exchange system thereof

Abstract

The invention discloses heat exchange equipment and a heat exchange system thereof, belongs to the field of flue gas waste heat recovery, and solves the problem that in the prior art, a variable-diameter flue is prone to damage when double heat exchangers treat waste heat of dusty flue gas, and according to the technical scheme for solving the problem, the heat exchange equipment comprises a first heat exchanger and a second heat exchanger; flue gas sequentially flows through the first heat exchanger and the second heat exchanger, the first heat exchanger and the second heat exchanger are connected through a variable-diameter flue, a large opening of the variable-diameter flue is connected with an outlet of the first heat exchanger, a small opening of the variable-diameter flue is connected with an inlet of the second heat exchanger, and a plurality of flow guide plates arranged at intervals are arranged in the variable-diameter flue. The guide plate is arranged on the side wall of the variable-diameter flue, so that the guide plate separates part of smoke dust from impacting the path of the side wall of the variable-diameter flue, and the guide plate is inclined to the flowing direction of the smoke to change the flowing direction of the smoke. The flue gas heat exchanger is mainly used for reducing dust in flue gas and prolonging the service life of heat exchange equipment.

Description

Technical Field

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

[0002] Plate heat exchanger is a kind of high-efficiency heat exchange equipment. Its structure is mainly composed of plates, sealing gaskets, clamping bolts, pressure plates, and pipes. The plates are stamped from metal sheets with various surface corrugations, which not only enhances strength but also improves heat transfer; sealing gaskets prevent fluid leakage; clamping bolts and pressure plates ensure that the plates are tightly connected; pipes are used for fluid in and out. When working, based on the principle of inter-wall heat exchange, cold and hot fluids flow on both sides of adjacent plates, and heat is transferred through the plates. Due to its corrugated structure, the fluid presents a complex flow state, which greatly improves the heat exchange efficiency. As the flue gas flows in the heat exchanger, it will be affected by the friction of the pipe wall, the resistance of internal components, etc., resulting in a gradual decrease in pressure, a weakening of the power to push the flue gas flow, and a decrease in flow rate. The flue gas exchanges heat in the heat exchanger and its temperature decreases. According to the ideal gas state equation (PV = nRT), when the pressure does not change much, the temperature decrease will reduce the gas volume, while the mass flow rate remains unchanged. According to (v = Q / A) (v is the flow velocity, Q is the volume flow rate, and A is the cross-sectional area of ​​the pipe), when the volume flow rate decreases, the flow velocity will decrease, so the flow velocity at the smoke outlet will decrease.

[0003] When using dual heat exchangers for heat exchange, a variable diameter flue is usually used to connect the two heat exchangers to ensure that the downstream heat exchanger maintains a certain speed and a certain heat exchange efficiency. In the waste heat recovery of dusty flue gas, the dust in the flue gas will hit the inner wall of the variable diameter flue when passing through the variable diameter flue, forming a local vortex of dust, which seriously wears the inner wall of the variable diameter flue. After long-term use, it will cause damage to the flue and peeling of the side walls of the flue. These peeled materials will form larger particles together with the dust and enter the downstream heat exchanger, causing dust accumulation in the downstream heat exchanger and other conditions that affect 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 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 difficulty. Summary of the invention

[0004] In order to overcome the deficiency in the prior art that the variable diameter flue of the double heat exchanger is easily damaged when recovering waste heat from dusty flue gas, the present application provides a heat exchange device and a heat exchange system thereof, which reduces the direct impact of dust in the flue gas on the flue and thus prolongs the life of the heat exchange device.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solution: a heat exchange device, comprising 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 mouth of the variable diameter flue is connected to the outlet of the first heat exchanger, and the small mouth is connected to the inlet of the second heat exchanger, and a plurality of guide plates arranged at intervals are provided in the variable diameter flue so that the guide plates block the path of part of the smoke and dust hitting the side wall of the variable diameter flue, and the guide plates are inclined to the flow direction of the smoke to change the flow direction of the smoke.

[0006] After adopting the above technical scheme, the present application has the following advantages: since the variable diameter flue has a large mouth and a small mouth, there is at least one side wall inclined to the direction of smoke flow, and this side wall will be directly hit by dust in the smoke, and a plurality of guide plates arranged at intervals are arranged on the path where the smoke hits the variable diameter flue, which greatly reduces the number of times the variable diameter flue is hit by smoke, and part of the smoke will enter between two adjacent guide plates for collision. Due to the different inertial kinetic energy of dust and gas, the speed of smoke particles will be greatly reduced after colliding with the guide plate, and their kinetic energy is insufficient to support them to continue to flow with the smoke. Under the action of gravity, they will be separated from the smoke. The smoke and dust will settle to the bottom of the variable diameter flue, thereby separating part of the smoke from the flue gas and achieving the dust removal effect. In addition, since a plurality of guide plates are arranged at intervals in the variable diameter flue, the variable diameter flue can be divided into a plurality of channels for circulating smoke, so that the smoke guiding effect is better, and the smoke in the variable diameter flue can be guided by the guide plates and enter the downstream equipment stably without much eddy current phenomenon, thereby reducing the damage to the downstream equipment. If the guide plates are not designed, the smoke and dust will all hit the side walls of the variable diameter flue, and the inner wall of the variable diameter flue will be damaged due to long-term use. In severe cases, the side wall will fall off, and the dust removal effect cannot be achieved. Compared with the method of reinforcing the inner wall of the variable diameter flue by coating or high-strength materials in the prior art, this solution does not need to use special coatings or high-strength materials. Only a small amount of guide plates are added to extend the life of the equipment and achieve partial dust removal.

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

[0008] With the above technical solution, the guide plate is tilted downward, which makes it easier for smoke particles to settle faster under the action of gravity while changing the direction of smoke flow. Since the direction of gravity is consistent with the tilt direction of the guide plate, after the smoke particles collide with the guide plate, in addition to losing kinetic energy due to their own inertia and collision, they will also settle to the bottom of the variable diameter flue faster under the additional action of gravity, thereby further improving the dust removal efficiency, separating more smoke from the smoke, and reducing the amount of smoke entering the downstream heat exchanger.

[0009] Furthermore, the variable diameter flue is provided with an airflow distribution plate located downstream of the guide plate, and the airflow distribution plate is provided with a plurality of cavities bulging outward, the cavities include a first cavity and a second cavity, and the volume of the first cavity near the downstream is smaller than the volume of the second cavity near the upstream.

[0010] With the above-mentioned technical solution, the airflow distribution plate makes the flue gas flow more smoothly, reduces the eddy current and the violent fluctuation of the airflow, thereby reducing the possibility of the dust that has settled to the bottom of the flue being lifted up again by the airflow, that is, suppressing the secondary dust phenomenon, which helps to keep the flue clean and improve the overall dust removal effect. When the flue gas passes through the cavity of the airflow distribution plate, the flow direction and speed are constantly changing, which increases the probability of collision between dust particles in the flue gas. According to the theory of condensation, the collision between particles will cause them to condense into larger particles, and large dust particles are more easily separated from the flue gas due to gravity, further improving the dust removal efficiency.

[0011] Furthermore, the cavity extends up and down to the edge of the airflow distribution plate, so that the dust particles in the smoke are settled along the outer surface of the cavity to the bottom of the variable diameter flue.

[0012] With the above-mentioned technical solution, the cavity extends up and down to the edge of the airflow distribution plate, which greatly increases the path for dust particles to contact and settle on the cavity surface. During the flow of flue gas, dust particles have more opportunities to collide or contact with the cavity surface. Once in contact, due to gravity and the adhesion between the particles and the cavity surface, it is easier to settle down 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 flue gas is provided upstream of the first heat exchanger.

[0014] With the above-mentioned technical solution, flue gas usually contains a certain amount of dust and other particles. The faster the flow speed, the stronger the scouring and wear effect on the inner wall of equipment such as heat exchangers. After the pre-dust collector removes a certain amount of dust, it reduces the flow speed of the flue gas, which can reduce the impact of the remaining dust and other particles in the flue gas on the first heat exchanger, and reduce the subsequent flue gas speed entering the variable flue, protecting the side walls of the variable flue from high-speed impact, which can extend the service life of the variable flue. The pre-dust collector reduces the flue gas speed, which can make the flow of flue gas in the first heat exchanger more stable and orderly, allowing the cold and hot fluids to exchange heat more fully and stably based on the principle of inter-wall heat exchange, improve the heat exchange efficiency of the first heat exchanger, and prevent the heat exchanger from wear and corrosion caused by high-speed scouring of flue gas, which can 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] By adopting the above technical solution, different opening center angle ranges allow the dust removal component to be adjusted according to actual flue gas flow, dust content, flow rate and other working conditions. For flue gas with high dust content and large flow, a larger opening center angle can be selected to improve the processing capacity; for working conditions with extremely high dust removal efficiency requirements, a suitable smaller opening center angle can be selected to enhance the centrifugal separation effect, thereby enhancing the adaptability of the equipment to different working conditions.

[0021] Furthermore, an ash hopper with an air lock is provided at the lower side of the pre-dust collector and / or the variable-diameter flue.

[0022] With the above technical solution, when dust needs to be cleaned, it can be discharged through the outlet of the ash hopper. The design with air lock ensures that the airflow state in the system will not be affected when dust is discharged, and there is no need to completely interrupt the operation of the system, which facilitates the maintenance personnel to perform cleaning operations and reduces the maintenance workload and difficulty.

[0023] A heat exchange system includes the above-mentioned heat exchange equipment, wherein 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 above 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 condensation on the flue gas side caused by the low temperature medium when exchanging heat with the high temperature flue gas, and the heated medium flowing out of the second heat exchanger is used to increase the temperature of the medium in the first heat exchanger that exchanges heat with the flue gas. 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 condensation on the flue gas side. Condensation can cause corrosion, blockage and other problems. Reducing condensation can protect equipment and extend the service life of equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present application is further described below in conjunction with the accompanying drawings: Figure 1 A schematic diagram of a heat exchange device and a heat exchange system thereof for the present application; Figure 2 The schematic diagram of the variable diameter flue is shown in FIG. Figure 3 for Figure 2 A top view of the middle air flow distribution plate; Figure 4 is a top view of the pre-dust collector; Figure 5 It is an enlarged view of the dust removal component; Figure 6 This is a diagram of the composition of the dust collection cylinder; Figure 7 is a schematic diagram of another embodiment of a heat exchange system; Description of the drawings: 1. First heat exchanger; 2. Second heat exchanger; 3. Variable diameter flue; 31. Guide plate; 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. Vortex part; 53. Air outlet; 6. Dust removal cylinder; 61. First arc cylinder; 62. Second arc 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. Deoxidizer; 8. Water-to-water heat exchanger; 81. Zone to be heated; 82. Circulation zone; 83. Circulating water pump; 9. Flue. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0027] The terms "first", "second", etc. (if any) in the specification 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 before a certain technical feature, it does not necessarily indicate that it has "first". It should be understood that in this application, "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. It should be understood that in this application, "multiple" refers to two or more. "And / or" is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, X and / or Y can represent: X exists alone, X and Y exist at the same time, and Y exists alone. The character " / " generally indicates that the related objects before and after are in an "or" relationship. "Contains X, Y and Z", "Contains X, Y, Z" means that X, Y, and Z are all included, "Contains X, Y or Z" means that one of X, Y, and Z is included, and "Contains X, Y and / or Z" means that any one, any two, or three of X, Y, and Z are included.

[0028] The following specific embodiments are used to describe the technical solution of the present application in detail. The following specific embodiments can be combined or replaced with each other according to actual conditions, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0029] like Figures 1 to 7 As shown, the present application provides a heat exchange device, including a first heat exchanger 1 and a second heat exchanger 2, the 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 variable diameter flue 3, the large mouth of the variable diameter flue 3 is connected to the outlet of the first heat exchanger 1, and the small mouth is connected to the inlet of the second heat exchanger 2, and a plurality of guide plates 31 arranged at intervals are provided in the variable diameter flue 3 so that the guide plates 31 block the path of part of the smoke and dust hitting the side wall of the variable diameter flue 3, and the guide plates 31 are inclined to the flow direction of the smoke to change the flow direction of the smoke.

[0030] After adopting the above technical scheme, the present application has the following advantages: since the variable diameter flue 3 has a large mouth and a small mouth, there is at least one side wall inclined to the flow direction of the smoke, and this side wall will be directly hit by the dust in the smoke, and a plurality of guide plates 31 arranged at intervals are arranged on the path where the smoke hits the variable diameter flue 3, which greatly reduces the number of times the variable diameter flue 3 is hit by the smoke, and part of the smoke will enter between two adjacent guide plates 31 for collision. Due to the different inertial kinetic energy of dust and gas, the speed of the smoke particles will be greatly reduced after colliding with the guide plates 31, and their kinetic energy is insufficient to support them to continue to flow with the smoke. Under the action of gravity, they will be separated from the smoke. It settles to the bottom of the variable diameter flue 3, thereby realizing the separation of part of the smoke and flue gas, achieving the effect of dust removal, and because a plurality of guide plates 31 arranged at intervals are arranged in the variable diameter flue 3, the variable diameter flue 3 can be divided into a plurality of channels for circulating smoke, so that the guiding effect of the smoke is better, so that the smoke in the variable diameter flue 3 can be guided by the guide plates 31 and enter the downstream equipment stably without more eddy currents, reducing the damage to the downstream equipment. If the guide plates 31 are not designed, the smoke will all hit the side wall of the variable diameter flue 3, and the inner wall of the variable diameter flue 3 will be damaged after long-term use, and the side wall will fall off in severe cases, and the dust removal effect cannot be achieved. And compared with the method of reinforcing the inner wall of the variable diameter flue 3 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 a small amount of guide plates 31 are added to extend the life of the equipment and achieve partial dust removal.

[0031] Preferably, 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, and the connecting lines formed by the ends of all the guide plates 31 form an angle of 30°-75° with the horizontal, preferably 40°-60°.

[0032] It can be understood that this solution is a flue gas improvement measure between two heat exchangers, and can also be used as a flue gas improvement solution between every two heat exchangers in a heat exchanger system with multiple heat exchangers. The guide plate 31 can be fixedly connected to the variable diameter flue 3 by welding or the like, or connected to the variable diameter flue 3 by a detachable connection method such as bolt connection.

[0033] Furthermore, the guide plates 31 are arranged at intervals up and down and are inclined downward to the flow direction of the smoke.

[0034] With the above technical solution, the guide plate 31 is tilted downward, so that while changing the direction of smoke flow, it is more conducive to the accelerated sedimentation of smoke particles under the action of gravity. Since the direction of gravity is consistent with the tilt direction of the guide plate 31, after the smoke particles collide with the guide plate 31, in addition to losing kinetic energy due to their own inertia and collision, they will also settle to the bottom of the variable diameter flue 3 faster under the additional action of gravity, thereby further improving the dust removal efficiency, separating more smoke from the smoke, and reducing the amount of smoke entering the downstream heat exchanger.

[0035] Furthermore, the variable diameter flue 3 is provided with an airflow distribution plate 32 located downstream of the guide plate 31, and the airflow distribution plate 32 is provided with a plurality of cavities 33 bulging outwards, and the cavities 33 include a first cavity 331 and a second cavity 332, such as Figure 3 As shown, the volume of the first cavity 331 close to the downstream is smaller than the volume of the second cavity 332 close to the upstream.

[0036] With the above-mentioned technical solution, the airflow distribution plate 32 makes the flue gas flow more smoothly, reduces the eddy current and the violent fluctuation of the airflow, thereby reducing the possibility that the dust that has settled to the bottom of the variable diameter flue 3 will be lifted up again by the airflow, that is, the secondary dust phenomenon is suppressed, which helps to keep the variable diameter flue 3 clean and improve the overall dust removal effect. When the flue gas passes through the cavity 33 of the airflow distribution plate 32, the flow direction and speed are constantly changing, which increases the probability of collision between dust particles in the flue gas. According to the condensation theory, the collision between particles will cause them to condense into larger particles, and large particles of dust are more easily separated from the flue gas due to gravity, further improving the dust removal efficiency.

[0037] 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 a double-sided convex bulge with a hollow cavity shape, and the heights of adjacent convex bulges decrease along the air flow direction, such as Figure 3 As shown, the height of the second cavity at the upstream is h1, the height of the first cavity at the downstream is h2, the ratio is 1.1-1.5, preferably 1.3; the length of the cavity 33 decreases in sequence along the airflow direction, such as Figure 3 As shown, the length of the upstream second cavity 332 is L1, the length of the downstream first cavity 331 is L2, the ratio is 1.1-1.5, preferably 1.3; the spacing between adjacent cavities 33 is the average length of the left and right cavities 33 along the direction of smoke flow, as shown in FIG. Figure 3 L3 in.

[0038] Furthermore, the cavity 33 extends up and down to the edge of the airflow distribution plate 32 so that the dust particles in the smoke settle along the outer surface of the cavity 33 to the bottom of the variable-diameter flue 3 .

[0039] With the above technical solution, the cavity 33 extends up and down to the edge of the airflow distribution plate 32, which greatly increases the path for dust particles to contact and settle on the surface of the cavity 33. During the flow of flue gas, dust particles have more opportunities to collide or contact with the surface of the cavity 33. Once in contact, due to gravity and the adhesion between the particles and the surface of the cavity 33, it is easier to settle down along the outer surface of the cavity 33 to the bottom of the variable-diameter flue 3, thereby improving the dust removal efficiency and effectively reducing the amount of dust entering the downstream heat exchanger.

[0040] Furthermore, a pre-dust collector 4 for reducing the flow velocity of flue gas is provided upstream of the first heat exchanger 1 .

[0041] With the above-mentioned technical solution, the flue gas usually contains a certain amount of dust and other particles. The faster the flow speed, the stronger the scouring and abrasion effect on the inner wall of the heat exchanger and other equipment. After the pre-dust collector 4 removes a certain amount of dust, it reduces the flue gas flow speed, which can reduce the impact of the remaining dust and other particles in the flue gas on the first heat exchanger 1, and reduce the subsequent flue gas speed entering the variable flue 3, protecting the side wall of the variable flue 3 from high-speed impact, and can extend the service life of the variable flue 3. The pre-dust collector 4 reduces the flue gas speed, which can make the flow of flue gas in the first heat exchanger 1 more stable and orderly, allowing the cold and hot fluids to exchange heat more fully and stably based on the principle of inter-wall heat exchange, improve the heat exchange efficiency of the first heat exchanger 1, and prevent the heat exchanger from wear and corrosion caused by high-speed scouring of flue gas, which can extend the service life of the heat exchanger.

[0042] Furthermore, the pre-dust collector 4 is composed of a plurality of dust removal components 5 staggeredly distributed along the flue gas, and the dust removal component 5 includes an air inlet 51, a vortex portion 52 and an air outlet 53, and the air inlet 51 and the air outlet 53 are arranged at the same place.

[0043] By adopting the above-mentioned 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 51 and the air outlet 53 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 53. 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 part of the smoke dust is settled after lacking kinetic energy. On the other hand, when the dust-containing flue gas enters the vortex part 52, 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.

[0044] Specifically, a gap of about 30 mm to 50 mm is left between the top of all dust removal components 5 and the top wall of the flue 9. The bottom of all dust removal components 5 is flush with the upper horizontal line of the ash hopper 41. An airtight baffle is provided below each dust removal component 5 to prevent flue gas short circuit. The airtight baffle extends into the ash hopper 41. An ash falling channel is left between the end of the baffle and the wall of the ash hopper 41. The upper part of the airtight baffle overlaps the dust removal component 5 by 200 mm to prevent flue gas short circuit. All dust removal components 5 are made of wear-resistant metal, such as 16Mn plate.

[0045] Furthermore, the dust removal component 5 is composed of two dust removal cylinders 6 mirror images, and the dust removal cylinder 6 includes a radius of The first arc tube 61 and the radius are The first arc tube 61 and the second arc tube 62 both have openings, one end of the first arc tube 61 faces the direction of smoke inflow, and the other end is connected to one end of the second arc tube 62, and the other end of the second arc tube 62 faces away from the direction of smoke inflow, wherein There is a gap between one end of the first arc tube 61 facing the smoke and one end of the second arc tube 62 facing away from the smoke, so that the smoke can enter the first arc tube 61 and the second arc tube 62.

[0046] Using the above technical solution, the radius of the first arc tube 61 is Greater than the radius of the second arc tube 62 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 61 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 toward 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 6. The mirror image composition of the two dust removal tubes 6 further enhances this dust removal effect.

[0047] Specifically, Figure 4As shown, the dust removal components 5 are evenly arranged in the cross section perpendicular to the flue gas flow direction. The first row is arranged with dust removal components 5 composed of two dust removal tubes 6. The number of dust removal components 5 in the second row is one less than that in the previous row. A dust removal tube 6 is arranged between 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 dust-containing flue gas flow rate passing through the gap is between 10 and 20 m / s, preferably 13 to 18 m / s. The center line of the gap formed by the outer edge of the front dust removal component 5 and the outer edge of the adjacent dust removal component 5 is aligned with the center line of the next row of vortex components along the flue gas flow direction. The dust removal components 5 in two adjacent rows are arranged in a regular staggered manner.

[0048] Preferably, .

[0049] Furthermore, the central angle of the opening of the first arc-shaped tube 61 is 60° to 180°, and the central angle of the opening of the second arc-shaped tube 62 is 180° to 270°.

[0050] By adopting the above technical solution, different opening central angle ranges enable the dust removal component 5 to be adjusted according to actual working conditions such as flue gas flow rate, dust content, flow rate, etc. For flue gas with high dust content and large flow rate, a larger opening central angle can be selected to improve the processing capacity; for working conditions with extremely high dust removal efficiency requirements, a suitable smaller opening central angle can be selected to enhance the centrifugal separation effect, thereby enhancing the adaptability of the equipment to different working conditions.

[0051] Preferably, the opening center angle of the first arc-shaped tube 61 is 135°, and the opening center angle of the second arc-shaped tube 62 is 270°.

[0052] Furthermore, an ash hopper 41 with an air lock is provided at the lower side of the pre-dust collector 4 and / or the variable-diameter flue 3 .

[0053] With the above technical solution, when dust needs to be cleaned, it can be discharged through the outlet of the ash hopper 41. The design with air lock does not affect the airflow state in the system when discharging dust, and there is no need to completely interrupt the operation of the system, which facilitates the maintenance personnel to perform cleaning operations and reduces the maintenance workload and difficulty.

[0054] A heat exchange system includes the above-mentioned heat exchange equipment, wherein 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.

[0055] By adopting the above technical solution, the second heat exchanger 2 preliminarily heats the water in the water tank 7, and the heated water 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 condensation on the flue gas side caused by the medium with a lower temperature when exchanging heat with the flue gas with a higher temperature, and the heated medium flowing out of the second heat exchanger 2 is used to increase the temperature of the medium in the first heat exchanger 1 that exchanges heat with the flue gas. 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 condensation phenomenon on the flue gas side. Condensation can cause problems such as corrosion and blockage. Reducing condensation can protect equipment and extend the service life of equipment.

[0056] 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 outlet of the first heat exchanger 1 is connected to the deaerator. A plate wear-resistant plate is provided in front of the plate heat exchanger in each stage of the heat exchanger, and each stage of the heat exchanger is provided with a refrigerant inlet header 72 and a refrigerant outlet header 73, and is provided with a corresponding inlet valve 74 and an outlet valve 75.

[0057] Preferably, multiple heat exchange plates are arranged along the flue gas flow direction in the heat exchanger, or several heat exchange modules composed of multiple heat exchange plates are arranged. The heat exchange plates are made of metal sheets through laser welding and expansion molding. The double surfaces of the heat exchange plates are wavy. "Dirty" media flows between the plates, and "clean" media flows inside the plates. The center spacing between two adjacent heat exchange plates is 20mm~50mm. The arrangement direction of the heat exchange plates is consistent with the flow direction of the hot flue gas. The heat exchange plates are made of ND steel, stainless steel, nickel-based alloy, etc., with a thickness of 0.5mm~3.0mm, preferably 1.0mm~2.5mm. If necessary, the metal surface is sprayed / brushed with an organic resin coating or inorganic coating with good thermal conductivity, heat resistance, wear resistance, and metal adhesion. The recommended coating thickness is 60~300 , preferably 100~250 .

[0058] 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.

[0059] like 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 a certain degree of dust removal, and then enters the second heat exchanger 2 for the second heat exchange, and finally enters the electrostatic precipitator 76 for dust removal before being discharged.

[0060] The liquid to be heated enters the second heat exchanger 2 from the water tank 7 through the water pump 71 for preliminary heating, then enters the first heat exchanger 1 for reheating, and finally enters the deoxidizer 77.

[0061] It can be understood that in another embodiment, Figure 7 As shown, the liquid to be heated enters the heating zone 81 of the water-to-water heat exchanger 8 from the water tank 7 through the water pump 71, wherein the water outlet of the heating zone 81 is connected to the deaerator 77, and the liquid in the circulation zone 82 is connected to the second heat exchanger 2 through the circulation water pump 83 for preliminary heating, and then enters the first heat exchanger 1 for reheating, and finally connected to the water inlet of the circulation zone 82.

[0062] In addition to the above-mentioned preferred embodiments, the present application also has other implementation modes. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection requested by the present application.

Claims

1. A heat exchange device, characterized in that: The invention comprises a first heat exchanger and a second heat exchanger, through which flue gas flows in sequence. The first heat exchanger and the second heat exchanger are connected via a variable diameter flue, wherein a large opening of the variable diameter flue is connected to an outlet of the first heat exchanger, and a small opening is connected to an inlet of the second heat exchanger. A plurality of guide plates arranged at intervals are arranged in the variable diameter flue so that the guide plates block the path of part of the smoke and dust hitting the variable diameter flue, and the guide plates are inclined to the flow direction of the smoke so as to change the flow direction of the smoke.

2. A heat exchange device according to claim 1, characterized in that: The guide plates are arranged at intervals up and down and are inclined downward in the direction of smoke flow.

3. A heat exchange device according to claim 1, characterized in that: The variable diameter flue is provided with an air flow distribution plate located downstream of the guide plate, and the air flow distribution plate is provided with a plurality of cavities bulging outwards, the cavities include a first cavity and a second cavity, and the volume of the first cavity near the downstream is smaller than the volume of the second cavity near the upstream.

4. A heat exchange device according to claim 3, characterized in that: The cavity extends up and down to the edge of the airflow distribution plate, so that the dust particles in the smoke are settled along the outer surface of the cavity to the bottom of the variable diameter flue.

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

6. A heat exchange device according to claim 5, characterized in that: 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.

7. A heat exchange device according to claim 6, characterized in that: The dust removal component is composed of two mirror images of dust removal cylinders, 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.

8. A heat exchange device according to claim 7, characterized in that: 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°.

9. The heat exchange device according to claim 5, characterized in that: An ash hopper with an air lock is provided at the lower side of the pre-dust collector and / or the variable-diameter flue.

10. A heat exchange system, characterized in that: A heat exchange device comprising any one of claims 1 to 9, wherein 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.

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