A gypsum board drying waste heat recovery system, method and heat exchanger thereof

Abstract

The application discloses a gypsum board drying waste heat recovery system and method and a heat exchanger thereof. The heat exchanger comprises a fluid channel and a slow flow part. The fluid channel comprises two concentric spiral flow channels formed by two parallel bending plates. The two sides of the bending plates are provided with cover plates, and the center of the two spiral flow channels is provided with a partition plate. The partition plate is fixedly connected to the end of the two spiral flow channels, and the partition plate separates the spiral flow channels to form a cold flow channel and a hot flow channel. The cover plates are provided with cold flow inlets / outlets and hot flow inlets / outlets. The cold flow channel is provided with a slow flow part for reducing the fluid speed. The cold flow and the hot flow can advance along the spiral direction to form a rotational flow through the spiral flow channel, the flow time is increased to improve the heat exchange effect, and the flowability of the low-temperature floor heating water is further reduced through the slow flow part in the cold flow channel, so that the heat utilization efficiency is improved under the same flow rate of the hot flow, and the heat exchange effect is enhanced.

Description

Technical Field

[0001] This invention relates to the field of waste heat recovery and utilization equipment, specifically to a waste heat recovery system, method and heat exchanger for gypsum board drying. Background Technology

[0002] The drying equipment used in the wet forming and drying process of paper-faced gypsum board generates a large amount of heat at its exhaust port. If the waste heat generated during this drying process cannot be utilized, it will result in serious waste of resources.

[0003] In existing technologies, waste heat recovery and utilization are mainly achieved through indirect heat exchangers. These utilize the heat conduction of a medium, separating the cold and hot media through a solid partition, through which heat exchange occurs. Depending on their structure, indirect heat exchangers can be further classified into tube heat exchangers, plate heat exchangers, and heat pipe heat exchangers. Although there are many types of heat exchangers in existing technologies, they generally suffer from problems such as poor heat exchange efficiency and uneven heat conduction.

[0004] Therefore, there is a need to provide a waste heat recovery system, method and heat exchanger for gypsum board drying to solve the problem of low heat utilization rate in existing heat exchangers. Summary of the Invention

[0005] The purpose of this invention is to provide a waste heat recovery system, method and heat exchanger for gypsum board drying, so as to solve the problem of poor gas-to-liquid heat transfer efficiency in existing heat exchangers.

[0006] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0007] In a first aspect of the invention, a heat exchanger is provided, comprising: a fluid channel including two concentric spiral channels formed by rolling two parallel bent plates; cover plates are provided on both sides of the bent plates to close the spiral path of the spiral channels; a partition is provided in the center of the two spiral channels, the partition being fixed to the ends of the two spiral channels respectively, the partition separating the spiral channels to form a cold flow channel and a hot flow channel, wherein cold and hot fluids flow in the cold flow channel and the hot flow channel respectively in the same direction / opposite direction; a cold flow port and a hot flow port are provided on the cover plate for fluid inflow / outflow; the cold flow port is located in the cold flow channel, and the hot flow port is located in the hot flow channel; the cold flow port and the hot flow port are disposed close to the partition to allow fluid to flow in / out from both ends of the spiral channels; a flow-retarding section is provided in the cold flow channel for reducing the fluid velocity.

[0008] Furthermore, the flow-slowing section includes flow-slowing plates; wherein, the flow-slowing plates are disposed on the side wall of the bent plate, and a gap is left between the end of the flow-slowing plates and the other bent plate and the two cover plates for fluid to pass through; the flow-slowing plates are equidistantly arranged along the bending path of the bent plate.

[0009] Furthermore, the flow-retarding plate is inclined in the direction of fluid flow; the angle between the normal of the flow-retarding plate and the wall surface of the bend plate is between 30° and 60°; wherein, the flow-blocking surface of the bend plate gradually increases along the bending path of the bend plate.

[0010] Furthermore, the flow-retarding section includes a flow-retarding plate; wherein, the flow-retarding plate is disposed on the cover plate, and a gap for fluid to pass through is left between the end of the flow-retarding plate and the two bent plates and the other cover plate; the flow-retarding plate is inclined in the direction of fluid flow; the included angle between the flow-retarding plate and the cover plate is between 30° and 60°; the flow-retarding surface of the flow-retarding plate gradually increases along the bending path of the bent plates.

[0011] Furthermore, the sidewall of the hot flow channel protrudes into the cold flow channel to form an annular cavity; wherein the cross-section of the annular cavity is a 3 / 4 circle opening towards the cold flow channel.

[0012] Furthermore, the outer wall of the annular cavity is provided with flow-blocking plates, and the flow-slowing section includes flow-blocking plates; wherein, the flow-blocking plates are arranged circumferentially along the bending path of the annular cavity; and a gap is left between the flow-blocking plates, the bending plate, and the cover plate to allow fluid to pass through.

[0013] Furthermore, multiple flow-blocking plates are provided in the circumferential direction of the annular cavity, and the flow-blocking plates are inclined in the direction of fluid flow.

[0014] Furthermore, the two bent plates have different thicknesses to make the heat conduction capacity different on both sides of the spiral flow channel.

[0015] In a second aspect of the invention, a heat exchange and recovery system based on the utilization of waste heat from a gypsum board dryer is provided, wherein the heat exchanger provided by the invention comprises:

[0016] A heating device that uses a fluid as a heat storage medium to supply heat to the surroundings;

[0017] A temporary storage tank, which is connected to the heating device via a pipe, is used to temporarily store low-temperature fluids. The temporary storage tank is connected to the cold inlet to input the heat-absorbing medium into the heat exchanger.

[0018] The dryer has its heat exhaust port connected to the heat flow port via a pipe to input the heat-generating medium into the heat exchanger;

[0019] An insulated box, connected to the output end of the cold flow channel in a heat exchanger, is used to store high-temperature fluids.

[0020] In a third aspect of the present invention, a heat exchange recovery method based on the utilization of waste heat from a gypsum board dryer is provided, the steps of which are as follows:

[0021] S100, the dryer exhaust port discharges heat to the heat exchanger;

[0022] S200: The water pump leads the floor heating water to the heat exchanger, and the waste heat from the air discharged by the dryer is used to heat the floor heating water.

[0023] S300: The heated floor heating water is pumped to the floor heating pipes to form a circulation.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] This invention utilizes a spiral flow channel to allow cold and hot flows to advance along the spiral direction, forming a swirling flow and increasing the flow time to improve heat exchange efficiency. Furthermore, a slow-flow section is incorporated within the cold flow channel to further reduce the fluidity of the low-temperature underfloor heating water. This improves heat utilization efficiency and enhances heat exchange efficiency at the same flow rate as the hot flow. Consequently, the waste heat from the drying process in gypsum board manufacturing can be released through the exhaust port to heat the underfloor heating water, achieving waste heat recovery and recycling, reducing energy consumption, and minimizing pollution caused by the need for additional heating of underfloor heating water. Attached Figure Description

[0026] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0027] Figure 1 A three-dimensional structural diagram of a heat exchanger provided by the present invention;

[0028] Figure 2 for Figure 1 Top view;

[0029] Figure 3 A three-dimensional structural diagram of the heat exchanger in another embodiment of the present invention;

[0030] Figure 4 for Figure 3 Top view;

[0031] Figure 5 A cross-sectional view of a heat exchanger in another embodiment of the present invention;

[0032] Figure 6 for Figure 5 Enlarged view of section I;

[0033] Figure 7 A cross-sectional view of the annular cavity in another embodiment of the present invention;

[0034] Figure 8 for Figure 7 Side view of the middle choke plate;

[0035] Figure 9The present invention provides a flow chart of a heat exchange and recovery system based on the utilization of waste heat from a gypsum board dryer.

[0036] The labels in the diagram represent the following:

[0037] 1. Fluid channel; 1a. Bending plate; 11. Spiral flow channel; 111. Cold flow channel; 112. Hot flow channel; 12. Cover plate; 121. Cold flow port; 122. Hot flow port; 13. Baffle plate; 14. Annular cavity; 2. Slow flow section; 21. Slow flow plate; 22. Baffle plate. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] like Figure 1 As shown, the present invention provides a heat exchanger, comprising:

[0040] Fluid channel 1, which includes two concentric spiral channels 11 formed by rolling two parallel bent plates 1a;

[0041] Cover plates 12 are provided on both sides of the bent plate 1a to close the spiral path of the spiral flow channel 11;

[0042] A baffle 13 is provided in the center of the two spiral flow channels 11. The baffle 13 is fixed to the ends of the two spiral flow channels 11 respectively. The baffle 13 divides the spiral flow channels 11 into a cold flow channel 111 and a hot flow channel 112. The cold and hot fluids flow in the same direction / opposite direction in the cold flow channel 111 and the hot flow channel 112 respectively.

[0043] The cover plate 12 is provided with a cold flow port 121 and a hot flow port 122 for fluid inflow / outflow; the cold flow port 121 is located in the cold flow channel 111 and the hot flow port 122 is located in the hot flow channel 112; the cold flow port 121 and the hot flow port 122 are arranged close to the partition plate 13 so that the fluid flows in / out from both ends of the spiral flow channel 11; the cold flow channel 111 is provided with a slow flow section 2 for reducing the fluid velocity.

[0044] This invention aims to utilize the waste heat from the drying process of gypsum board manufacturing, released through the exhaust port, to heat the underfloor heating water by setting up the fluid channel 1. This achieves waste heat recovery and recycling, reduces energy consumption, and minimizes pollution caused by the need for additional heating of underfloor heating water. Specifically, in actual use, the heat exchanger can connect the exhaust port of the gypsum board dryer and the hot flow port 122 through a high-temperature resistant ventilation pipe to introduce high-temperature airflow into the hot flow channel 112. The heated hot flow channel 112 preheats the adjacent cold flow channel 111. Then, low-temperature underfloor heating water is introduced into the cold flow channel 111 from the cold flow port 121. Subsequently, the water flowing into the cold flow channel 111 can exchange heat with the hot airflow in the hot flow channel 112 through the intermediate bend plate 1a. Finally, when the underfloor heating water is heated to a certain temperature, it is discharged from the other end of the cold flow channel 111 into the underfloor heating pipe for reheating. Thus, the waste heat from the drying of gypsum board is fully utilized.

[0045] It should be noted that, in actual use, the heat exchanger provided by this invention does not restrict the direction of entry of the underfloor heating water and the hot air flow. That is, the underfloor heating water and the hot air flow can move in the same or opposite directions within their respective fluid channels 1, thereby adjusting the heat exchange rate according to the velocity difference between the cold and hot flows. On the other hand, the heat exchanger provided by this invention not only enables the cold and hot flows to advance along the spiral direction to form a swirling flow by setting the spiral flow channel 11, increasing the flow time to improve the heat exchange effect, but also, since the specific heat capacity of the liquid is greater than that of the gas, the temperature of the liquid is not easily changed. Therefore, a slow flow section 2 is set in the cold flow channel 111 to further reduce the fluidity of the low-temperature underfloor heating water, thereby improving its heat utilization efficiency and enhancing the heat exchange effect at the same flow rate of the hot flow.

[0046] To clearly illustrate the function of the flow buffer 2 in this invention, specific embodiments are provided below.

[0047] In one embodiment of the present invention, the flow-slowing section 2 includes a flow-slowing plate 21;

[0048] The flow-slowing plate 21 is located on the side wall of the bent plate 1a. A gap is left between the end of the flow-slowing plate 21 and the other bent plate 1a and the two cover plates 12 to allow fluid to pass through. The flow-slowing plate 21 is equidistantly arranged along the bending path of the bent plate 1a.

[0049] More specifically, the flow-retarding plate 21 is inclined toward the direction of fluid flow; the angle between the flow-retarding plate 21 and the normal to the wall of the bent plate 1a is between 30° and 60°.

[0050] The flow-blocking surface of the bent plate 1a gradually increases along the bending path of the bent plate 1a.

[0051] In this embodiment, by setting an inclined flow-delaying plate 21 on the bent plate 1a, the water flow in the spiral channel 11 can be diverted during the impact of the bent plate 1a, so that part of the water flow is deflected back to impact the original flow path of the water flow, thereby reducing the fluid velocity in the spiral channel 11. Moreover, the area of ​​the flow-delaying plate 21 gradually increases, so that the flow-delaying capacity of the flow-delaying plate 21 gradually increases, thereby gradually reducing the flow velocity of the water flow in the spiral channel 11. It should be noted that in this embodiment, the flow-delaying surface area can be adjusted by setting the flow-facing surface of the flow-delaying plate 21 as a concave curved surface or a wave shape, or by setting evenly distributed countersunk holes on the flow-facing surface, so as to achieve the purpose of slowing down the fluid by increasing the contact area between the water and the flow-delaying plate 21.

[0052] like Figure 3-4 As shown, in another embodiment of the present invention, the flow-retarding section 2 includes a flow-retarding plate 21;

[0053] The flow-retarding plate 21 is disposed on the cover plate 12. A gap is left between the end of the flow-retarding plate 21 and the two bent plates 1a and the other cover plate 12 to allow fluid to pass through. The flow-retarding plate 21 is inclined in the direction of fluid flow. The included angle between the flow-retarding plate 21 and the cover plate 12 is between 30° and 60°. The flow-retarding surface of the flow-retarding plate 21 gradually increases along the bending path of the bent plate 1a.

[0054] In this embodiment, by providing an inclined flow-slowing plate 21 on the cover plate 12, the water flow in the spiral channel 11 can be diverted to flow on both sides, thereby slowing down the flow.

[0055] like Figure 6-7 As shown, in another embodiment of the present invention, the sidewall of the hot flow channel 112 protrudes into the cold flow channel 111 to form an annular cavity 14;

[0056] The cross-section of the annular cavity 14 is a 3 / 4 circle that opens toward the cold flow channel 111.

[0057] In this embodiment, the annular cavity 14 allows the bent plate 1a to first heat the center of the cold flow using the heat flow within the annular cavity 14 during heat transfer. This not only increases the contact area between the cold and hot flows but also makes the heating effect of the cold flow more uniform, effectively avoiding the problem of uneven heating and insufficient heating of the cold flow when the bent plate 1a conducts heat on one side. It should be noted that the annular cavity 14 is preferably located in the middle of the side wall of the heat flow channel 112 to preferentially heat the center flow of the cold flow. In addition, to improve heating efficiency and further enhance the uniformity of heating of the cold flow, multiple annular cavities 14 can also be arranged above or below the side wall of the heat flow channel 112. The cross-sectional size of the annular cavity 14 can also be adjusted according to the actual water flow rate and water flow height in the heat flow channel 112 to obtain the optimal contact area between the cold and hot flows, thereby improving the heat utilization efficiency.

[0058] To address the problem of excessively high fluid velocity within the cold flow channel 111, resulting in poor heat exchange efficiency, such as... Figure 7-8 As shown, in another embodiment of the present invention based on the above embodiments, a flow-blocking plate 22 is provided on the outer wall of the annular cavity 14, and the flow-slowing part 2 includes the flow-blocking plate 22;

[0059] The flow-blocking plate 22 is arranged circumferentially along the bending path of the annular cavity 14; a gap is left between the flow-blocking plate 22, the bending plate 1a, and the cover plate 12 to allow fluid to pass through.

[0060] More specifically, multiple flow-blocking plates 22 are provided in the circumferential direction of the annular cavity 14, and the flow-blocking plates 22 are inclined in the direction of fluid flow.

[0061] In this embodiment, by setting multiple inclined baffles 22 on the annular cavity 14, the flow state of the cold flow in the cold flow channel 111 can be disturbed, thereby reducing the fluid velocity. It should be noted that in actual use, the baffles 22 provided in this embodiment are preferably made of materials with good thermal conductivity, such as copper or aluminum, so that the heat of the hot flow stored in the annular cavity 14 can be transferred to the middle of the cold flow to heat the cold flow. More specifically, the fixed end of the baffle 22 can be inserted into the annular cavity 14, so that the heat of the hot flow stored in the annular cavity 14 can be directly transferred to the cold flow for absorption through the baffle 22, instead of just heat conduction through the wall of the annular cavity 14. Thus, the heat utilization efficiency in the hot flow channel 112 is improved by the heat transfer effect of the baffle 22 and the annular cavity 14 on the cold flow.

[0062] In the above embodiments, when the thickness and material of the bent plates 1a on both sides of the spiral flow channel 11 are the same, their thermal conductivity is the same when they act as heat transfer elements between the cold flow and the hot flow. When the cold flow is slow and the hot flow is fast, the heat of the hot flow is easily transferred to both sides of the spiral flow channel 11, rather than being concentrated on one side to heat the cold flow.

[0063] To resolve the above issues, please continue reading Figure 1-2 As shown, in the preferred embodiment of the present invention based on the above embodiments, the two bent plates 1a have different thicknesses so that the thermal conductivity on both sides of the spiral flow channel 11 is different. In this embodiment, by setting the bent plates 1a to have different thicknesses, the two sides of the spiral flow channel 11 are composed of two bent plates 1a of different thicknesses, thereby enabling heat flow to transfer heat to one side. Similarly, the material of the bent plates 1a can also be changed to change the heat transfer capacity.

[0064] like Figure 9 As shown, the present invention provides a heat exchange and recovery system based on the utilization of waste heat from a gypsum board dryer, which utilizes the heat exchanger provided in any embodiment of the present invention. The system includes:

[0065] Heating device 3 uses fluid as a heat storage medium to supply heat to the surroundings;

[0066] Temporary storage tank 4 is connected to heating device 3 via a pipe. Temporary storage tank 4 is used to temporarily store low-temperature fluid. Temporary storage tank 4 is connected to cold flow port 121 to input heat-absorbing medium into heat exchanger.

[0067] The dryer 5 has its heat exhaust port connected to the heat flow port 122 via a pipe to input the heat-generating medium into the heat exchanger;

[0068] The heat exchanger box 6 is connected to the output end of the cold flow channel 111 in the heat exchanger and is used to store high-temperature fluid.

[0069] This invention also provides a heat exchange recovery method based on the utilization of waste heat from a gypsum board dryer, the steps of which are as follows:

[0070] S100, the dryer exhaust port discharges heat to the heat exchanger;

[0071] S200: The water pump leads the floor heating water to the heat exchanger, and the waste heat from the air discharged by the dryer is used to heat the floor heating water.

[0072] S300: The heated floor heating water is pumped to the floor heating pipes to form a circulation.

[0073] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A heat exchanger, characterized in that, include: The fluid channel (1) comprises two concentric spiral channels (11) formed by rolling two parallel bent plates (1a). The bent plate (1a) is provided with cover plates (12) on both sides to close the spiral path of the spiral channel (11); A partition (13) is provided in the center of the two spiral flow channels (11). The partition (13) is fixed to the ends of the two spiral flow channels (11) respectively. The partition (13) divides the spiral flow channels (11) into a cold flow channel (111) and a hot flow channel (112). The cold and hot fluids flow in the same direction / opposite direction in the cold flow channel (111) and the hot flow channel (112) respectively. The cover plate (12) is provided with a cold flow port (121) and a hot flow port (122) for fluid inflow / outflow. The cold flow port (121) is located inside the cold flow channel (111), and the hot flow port (122) is located inside the hot flow channel (112); The cold flow port (121) and hot flow port (122) are located close to the partition (13) so that fluid flows in / out from both ends of the spiral flow channel (11); The cold flow channel (111) is provided with a flow-slowing section (2) for reducing the fluid velocity.

2. A heat exchanger according to claim 1, characterized in that, The flow-retarding section (2) includes a flow-retarding plate (21); The flow-slowing plate (21) is located on the side wall of the bent plate (1a), and there is a gap between the end of the flow-slowing plate (21) and the other bent plate (1a) and the two cover plates (12) for fluid to pass through. The flow-retarding plate (21) is equidistantly arranged along the bending path of the bent plate (1a).

3. A heat exchanger according to claim 2, characterized in that, The flow-retardant plate (21) is inclined toward the direction of fluid flow; The included angle between the wall normals of the flow-slowing plate (21) and the bending plate (1a) is between 30° and 60°; The flow-blocking surface of the bent plate (1a) gradually increases along the bending path of the bent plate (1a).

4. A heat exchanger according to claim 1, characterized in that, The flow-retarding section (2) includes a flow-retarding plate (21); The flow-slowing plate (21) is disposed on the cover plate (12), and a gap is left between the end of the flow-slowing plate (21) and the two bent plates (1a) and the other cover plate (12) for fluid to pass through. The flow-retardant plate (21) is inclined toward the direction of fluid flow; The included angle between the flow-damping plate (21) and the cover plate (12) is between 30° and 60°; The flow-blocking surface of the flow-retarding plate (21) gradually increases along the bending path of the bending plate (1a).

5. A heat exchanger according to claim 1, characterized in that, The sidewall of the hot flow channel (112) protrudes into the interior of the cold flow channel (111) to form an annular cavity (14). The cross-section of the annular cavity (14) is a 3 / 4 annular ring that opens toward the cold flow channel (111).

6. A heat exchanger according to claim 5, characterized in that, The outer wall of the annular cavity (14) is provided with a flow-blocking plate (22), and the flow-slowing part (2) includes the flow-blocking plate (22). The flow-blocking plate (22) is arranged circumferentially along the bending path of the annular cavity (14); A gap is left between the flow-blocking plate (22), the bending plate (1a), and the cover plate (12) to allow fluid to pass through.

7. A heat exchanger according to claim 6, characterized in that, Multiple flow-blocking plates (22) are provided in the circumferential direction of the annular cavity (14), and the flow-blocking plates (22) are inclined in the direction of fluid flow.

8. A heat exchanger according to any one of claims 1-7, characterized in that, The two bent plates (1a) have different thicknesses so that the thermal conductivity on both sides of the spiral channel (11) is different.

9. A gypsum board drying waste heat recovery system using the heat exchanger of claim 8, characterized in that, include: Heating device (3), which uses fluid as a heat storage medium to supply heat to the surroundings; A temporary storage tank (4) is connected to the heating device (3) via a pipe. The temporary storage tank (4) is used to temporarily store low-temperature fluid. The temporary storage tank (4) is connected to the cold flow port (121) to input the heat-absorbing medium into the heat exchanger. The dryer (5) has its heat exhaust port connected to the heat flow port (122) via a pipe to input the heat-generating medium into the heat exchanger; The heat exchange box (6), which is connected to the output end of the cold flow channel (111) in the heat exchanger, is used to store high-temperature fluid.

10. A method for recovering waste heat from gypsum board drying, comprising the following steps: S100, the dryer exhaust port discharges heat to the heat exchanger; S200: The water pump leads the floor heating water to the heat exchanger, and the waste heat from the air discharged by the dryer is used to heat the floor heating water. S300: The heated floor heating water is pumped to the floor heating pipes to form a circulation.

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