An indirect heating furnace and a method of indirectly heating process air

Abstract

The application relates to an indirect heating furnace and a method for indirectly heating process air, the indirect heating furnace comprising a fireproof tube assembly, an air outlet shell, a smoke exhaust shell, a heat exchange air duct assembly and a heat exchange assembly, wherein the fireproof tube assembly comprises an inner channel and an outer channel; the air outlet shell is provided with a burner connecting port communicated with the inner channel on one side and a process air outlet communicated with the outer channel on the other side; the smoke exhaust shell is provided with a smoke exhaust port on one side; the heat exchange air duct assembly is connected with the fireproof tube assembly and the smoke exhaust shell respectively, and is communicated with the inner channel and the outer channel; the heat exchange air duct assembly is provided with a process air inlet close to the smoke exhaust shell; the heat exchange assembly is located in the heat exchange air duct assembly, and one end of the heat exchange assembly is communicated with the smoke exhaust port, and the other end is communicated with the inner channel. The application can improve the heat exchange efficiency and save energy.

Description

Technical Field

[0001] This application relates to the field of indirect heating technology, and in particular to an indirect heating furnace and a method for indirect heating process air. Background Technology

[0002] Traditional indirect heating methods include steam heating, electric heating, and independent combustion chambers with independent heat exchangers. Steam heating requires a steam generator, resulting in a complex system with limited thermal efficiency. It also has a low heat source temperature, requires a large heat exchange area, and involves high initial investment and a large footprint. Electric heating has high energy consumption and is expensive for large-scale industrial applications. As for independent combustion chambers with independent heat exchangers, they have low equipment integration, long heat transfer distances, high heat loss, high initial investment, and a large footprint. In short, these traditional methods have significant drawbacks and do not meet the demands of modern development in terms of integration, cost, and energy consumption.

[0003] To address the aforementioned issues, several indirect heating devices with improved integration have emerged, such as heat exchange furnaces with integrated combustion chambers. These furnaces combine the combustion chamber and heat exchange equipment into a single unit, reducing floor space and offering cost advantages compared to traditional methods. However, these improved devices still suffer from several problems, primarily insufficient heat exchange efficiency and high energy consumption.

[0004] For details, please refer to Figure 1 As shown, in existing heat exchangers with combustion chambers, the combustion chamber is typically located on one side. Figure 1 The left side is the center, and the other side is set up with a heat exchange device. Figure 1 (Right side of the middle) The high-temperature flue gas generated in the combustion chamber flows inside the combustion chamber and the heat exchange equipment, and finally flows out from the flue gas outlet of the heat exchange equipment. Figure 1 The small and medium arrows indicate the flue gas path; simultaneously, the process air requiring heating enters from the inlet on one side of the combustion chamber, flows along the channel towards the heat exchanger, is heated by the high-temperature flue gas at the heat exchanger, and then flows out from the outlet on one side of the heat exchanger. The last process air to flow out is the heated process air. Figure 1 The route indicated by the large arrow is the process air route. In the above process, the heat exchange method is co-current heat exchange. During the heat exchange process, the temperature of the process air continuously rises, while the temperature of the flue gas exchanging heat with the process air continuously decreases. The temperature difference between the two will become smaller and smaller, resulting in a decrease in heat exchange efficiency. In fact, if the temperature of the flue gas downstream becomes lower than the temperature of the process air, there will be a situation where the process air transfers heat to the flue gas in reverse. To avoid this situation, in order to ensure that the temperature of the flue gas is always higher than the temperature of the process air, it is necessary to increase the initial flue gas temperature, making the initial flue gas temperature much higher than the required process air temperature, which leads to an increase in the energy required.

[0005] In summary, existing indirect heating technologies suffer from low heat exchange efficiency and high energy consumption.

[0006] Therefore, how to overcome the shortcomings of existing technologies and solve the problems of low heat exchange efficiency and high energy consumption in the indirect heating process of existing technologies is a problem to be solved in this technical field. Summary of the Invention

[0007] To address the aforementioned deficiencies or improvement needs of existing technologies, and to solve the problems of low heat exchange efficiency and high energy consumption in indirect heating processes, this application provides an indirect heating furnace and a method for indirectly heating process air. The furnace employs a counter-flow heat exchange design, allowing the process air to enter from the side closest to the flue gas outlet and exit from the side closest to the flue gas inlet. This ensures that the process air exchanges heat with the lower-temperature flue gas first at a lower temperature, and then with the higher-temperature flue gas at a higher temperature, maintaining a consistent temperature difference between the flue gas and the process air, thus improving heat exchange efficiency. Furthermore, based on this design, the initial flue gas temperature does not need to be too high; it only needs to be slightly higher than the required process air temperature. Compared to existing technologies where the initial flue gas temperature is much higher than the required process air temperature, this design can save significant energy consumption.

[0008] The embodiments of this application adopt the following technical solutions:

[0009] In a first aspect, this application provides an indirect heating furnace, including a fire shield assembly, an air outlet shell, a flue shell, a heat exchange duct assembly, and a heat exchange assembly, wherein:

[0010] The fire shield assembly includes an inner channel and an outer channel;

[0011] The air outlet housing has a burner connection port on one side that communicates with the inner channel, and a process air outlet on the other side that communicates with the outer channel.

[0012] A smoke exhaust port is provided on one side of the smoke exhaust housing;

[0013] The heat exchange duct assembly is connected to the fire shield assembly and the smoke exhaust shell respectively. The heat exchange duct assembly is connected to both the inner channel and the outer channel. The heat exchange duct assembly is provided with a process air inlet near the smoke exhaust shell.

[0014] The heat exchange component is located inside the heat exchange duct assembly, and one end of the heat exchange component is connected to the smoke exhaust port, while the other end is connected to the inner channel.

[0015] By adopting the above technical solution, the process air inlet is located close to the exhaust casing, i.e., close to the exhaust port; the burner connection port and the process air outlet are both located in the exhaust casing, i.e., the process air outlet is close to the flue gas inlet. Under the above arrangement, the transmission direction of the process air is opposite to the transmission direction of the flue gas, forming a counter-current heat exchange. This allows the process air to exchange heat with the lower-temperature flue gas first when the temperature is lower, and then with the higher-temperature flue gas when the temperature is higher, thus always maintaining the temperature difference between the flue gas and the process air and improving the heat exchange efficiency. At the same time, based on this design, the initial flue gas temperature does not need to be too high, only slightly higher than the final required process air temperature. Compared with the existing technology where the initial flue gas temperature is much higher than the final required process air temperature, this can save a lot of energy.

[0016] In some embodiments, the fire shield assembly includes an inner cylinder and an outer cylinder, with an inner channel formed inside the inner cylinder and an outer channel formed between the inner cylinder and the outer cylinder; the first end of the inner cylinder is connected and fixed to the inner wall of the air outlet housing on the side where the burner connection port is provided, and the first end of the outer cylinder is connected and fixed to the outer wall of the air outlet housing on the side away from the burner connection port, and a first through hole communicating with the outer cylinder is provided on the outer wall of the air outlet housing on the side away from the burner connection port.

[0017] By adopting the above technical solution, the flue gas channel and the process air channel at the fire shield assembly can be separated, so that the flue gas is confined in the inner channel and the process air is confined in the outer channel, thus avoiding the mixing and interference between the two.

[0018] In some embodiments, a spiral guide vane is provided between the inner cylinder and the outer cylinder.

[0019] By adopting the above technical solution, the spiral guide vane can effectively reduce the flow resistance, allowing the process air to flow spirally along the outer wall of the inner cylinder with uniform flow velocity distribution, and ensuring sufficient contact between the process air and the outer wall of the inner cylinder, which can effectively improve the heat exchange efficiency.

[0020] In some embodiments, the heat exchange duct assembly includes a first duct housing and a second duct housing, wherein the first duct housing and the second duct housing are arranged vertically.

[0021] The second air duct housing is provided with an isolation plate, the isolation plate is provided with a second through hole and a plurality of first smoke passage holes, and the second air duct housing is provided with a third through hole;

[0022] One part of the heat exchange component is disposed in the first air duct shell, and the other part is disposed in the second air duct shell and communicates with the first smoke passage hole;

[0023] The second end of the inner cylinder is fixed to the isolation plate and communicates with the second through hole, and the second end of the outer cylinder is fixed to the second air duct shell and communicates with the third through hole.

[0024] By adopting the above technical solution, the flue gas channel and the process air channel at the heat exchange duct assembly can be separated, so that the flue gas and process air are located on both sides of the isolation plate, avoiding the mixing and crosstalk between the two.

[0025] In some embodiments, the heat exchange assembly includes a plurality of heat exchange tubes, with each pair of adjacent heat exchange tubes arranged in a staggered, parallel configuration.

[0026] By adopting the above technical solution, the heat exchange tubes are arranged in a staggered and parallel manner, and a triangular arrangement is achieved between adjacent heat exchange tubes, resulting in high heat transfer efficiency.

[0027] In some embodiments, the heat exchange tube is provided with a first baffle and a second baffle, the first baffle having a gap between it and the lower inner wall of the first air duct housing, and the second baffle having a gap between it and the upper inner wall of the first air duct housing.

[0028] By adopting the above technical solution, the process air can be designed with two 180° reversal baffles, which can effectively improve the uniformity of the wind speed distribution at the heat exchange tube and ensure sufficient contact between the process air and the heat exchange tube, thereby improving the heat exchange efficiency.

[0029] In some embodiments, the exhaust housing has a plurality of second smoke passage holes on the side opposite to the exhaust port, and the heat exchange assembly communicates with the second smoke passage holes.

[0030] By adopting the above technical solution, the flue gas inside the heat exchange component can reach the exhaust housing through the second flue gas passage and then be discharged from the exhaust port.

[0031] In some embodiments, the exhaust housing is provided with a first air passage and a second air passage, and the air outlet housing is provided with a third air passage. The first air passage is connected to the heat exchange duct assembly, and the second air passage is connected to the third air passage.

[0032] The smoke exhaust housing is provided with a baffle plate inside, which divides the smoke exhaust housing into a first part and a second part. The smoke exhaust port and the second smoke passage hole are provided on the first part, and the first air passage hole and the second air passage hole are provided on the second part.

[0033] An air regulating component is provided at the second air passage, which is used to adjust the opening degree of the second air passage.

[0034] By adopting the above technical solution, the exhaust housing is divided into two parts. The first part is used for exhaust, and the second part is used for process air diversion. This allows a portion of the process air to pass directly into the outlet housing through the second part of the exhaust housing, where it merges with another portion of the process air heated by the flue gas and flows out from the process air outlet. At the same time, the opening of the second air passage is designed for adjustment, making the flow rate of the process air passing through the second part of the exhaust housing controllable, thereby enabling temperature regulation of the final output process air. This method can effectively eliminate the heat transfer lag of indirect heating, achieve rapid temperature control, and provide high temperature control accuracy.

[0035] In some embodiments, the air conditioning assembly includes an air conditioning housing, a plurality of blades, and a drive motor;

[0036] The blades are rotatably connected to the air conditioning housing via a rotating shaft. A first connecting piece is provided on the rotating shaft, and multiple first connecting pieces are connected to each other via second connecting pieces.

[0037] The output end of the drive motor is fixedly connected to one of the rotating shafts.

[0038] By adopting the above technical solution, the drive motor can drive a rotating shaft to rotate, which in turn drives the first connecting piece connected to it to rotate. In turn, the second connecting piece drives all the first connecting pieces and all rotating shafts to rotate synchronously, thereby realizing the adjustment of the blade angle, that is, the adjustment of the opening at the second air passage.

[0039] Secondly, this application provides a method for indirectly heating process air, applied to the indirect heating furnace described in the first aspect, comprising:

[0040] The burner is placed at the burner connection port, so that the high-temperature flue gas generated by the burner passes through the inner channel of the fire shield assembly, the inner channel of the heat exchange air duct assembly, and the inner channel of the heat exchange assembly in sequence, and is then discharged from the flue gas outlet of the exhaust shell.

[0041] The process air enters through the process air inlet of the heat exchange duct assembly, passes sequentially through the outer surface of the heat exchange assembly, the internal channel of the heat exchange duct assembly, and the outer channel of the fire shield assembly, and is then discharged from the process air outlet of the outlet shell.

[0042] By adopting the above technical solution, the transmission direction of the process air is opposite to that of the flue gas, forming a counter-current heat exchange, which improves heat exchange efficiency and saves energy.

[0043] Compared with the prior art, the beneficial effects of this application include, but are not limited to, the following:

[0044] 1. Position the process air inlet close to the exhaust casing, i.e., close to the exhaust port; position both the burner connection port and the process air outlet on the exhaust casing, i.e., position the process air outlet close to the flue gas inlet. With this configuration, the process air flow direction is opposite to the flue gas flow direction, forming a counter-current heat exchange. This allows the process air to exchange heat with the lower-temperature flue gas first when its temperature is lower, and then with the higher-temperature flue gas when its temperature is higher, thus maintaining a consistent temperature difference between the flue gas and the process air and improving heat exchange efficiency. Furthermore, based on this design, the initial flue gas temperature does not need to be too high; it only needs to be slightly higher than the final required process air temperature. Compared to existing technologies where the initial flue gas temperature is much higher than the final required process air temperature, this design can save significant energy consumption.

[0045] 2. The design of the first and second baffles enables two 180° reversal flow patterns for the process air, effectively improving the uniformity of the air velocity distribution at the heat exchange tubes and ensuring sufficient contact between the process air and the heat exchange tubes, thereby enhancing heat exchange efficiency. The spiral guide vane design effectively reduces flow resistance, allowing the process air to flow spirally along the outer wall of the inner cylinder, resulting in uniform velocity distribution and sufficient contact between the process air and the outer wall of the inner cylinder, further improving heat exchange efficiency.

[0046] 3. The exhaust housing is divided into two parts. The first part is used for exhaust, and the second part is used for process air diversion. This allows a portion of the process air to pass directly into the outlet housing through the second part of the exhaust housing, where it merges with another portion of the process air heated by the flue gas and flows out from the process air outlet. At the same time, the opening of the second air passage is designed for adjustment, making the flow rate of the process air passing through the second part of the exhaust housing controllable, thereby enabling temperature regulation of the final output process air. This method can effectively eliminate the heat transfer lag of indirect heating, achieve rapid temperature control, and provide high temperature control accuracy. Attached Figure Description

[0047] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A schematic diagram of the operation of a heat exchanger with a combustion chamber in the related technology provided in this application;

[0049] Figure 2 An exploded view of an indirect heating furnace provided in this application;

[0050] Figure 3 This application provides an overall structural schematic diagram of an indirect heating furnace;

[0051] Figure 4 This is a schematic diagram of the fire shield assembly provided in this application;

[0052] Figure 5 This is a schematic diagram of the spiral guide vane provided in this application;

[0053] Figure 6 A first-view structural schematic diagram of the air outlet housing provided in this application;

[0054] Figure 7 A structural schematic diagram of the air outlet housing provided in this application from a second perspective;

[0055] Figure 8 A partial perspective view of the heat exchange duct assembly provided in this application;

[0056] Figure 9 A schematic diagram of the structure of the heat exchange component provided in this application;

[0057] Figure 10 This is a first-view structural schematic diagram of the smoke exhaust casing provided in this application;

[0058] Figure 11 A structural schematic diagram of the smoke exhaust housing provided in this application from a second perspective;

[0059] Figure 12 A schematic diagram of the air conditioning component structure provided in this application;

[0060] Figure 13 Provided for this application Figure 3 Sectional view of AA;

[0061] Figure 14 A flowchart of an indirect heating process wind provided in this application.

[0062] Explanation of reference numerals in the attached figures:

[0063] 1. Fire shield assembly; 101. Inner channel; 102. Outer channel; 103. Inner cylinder; 104. Outer cylinder; 105. Spiral guide vane;

[0064] 2. Air outlet housing; 201. Burner connection port; 202. Process air outlet; 203. First through hole; 204. Third air passage hole;

[0065] 3. Smoke exhaust housing; 301. Smoke exhaust port; 302. Second smoke passage hole; 303. First air passage hole; 304. Second air passage hole; 305. Baffle plate;

[0066] 4. Heat exchange duct assembly; 401. First duct shell; 402. Second duct shell; 403. Isolation plate; 404. Second through hole; 405. First smoke passage hole; 406. Third through hole; 407. Process air inlet;

[0067] 5. Heat exchange assembly; 501. Heat exchange tube; 502. First baffle; 503. Second baffle;

[0068] 6. Air regulating assembly; 601. Air regulating housing; 602. Blade; 603. Drive motor; 604. Rotating shaft; 605. First connecting piece; 606. Second connecting piece. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0070] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments. Additionally, all connections in this application can refer to direct connections or indirect connections.

[0071] Example 1

[0072] like Figure 2 and Figure 3 As shown, Embodiment 1 of this application provides an indirect heating furnace, including a fire shield assembly 1, an air outlet shell 2, a flue shell 3, a heat exchange duct assembly 4, and a heat exchange assembly 5. The air outlet shell 2 and the flue shell 3 are stacked, and the fire shield assembly 1 is connected to the air outlet shell 2. The heat exchange duct assembly 4 is generally L-shaped, with one end connected to the flue shell 3 and the other end connected to the fire shield assembly 1. The heat exchange assembly 5 is disposed within the heat exchange duct assembly 4 and located above the fire shield assembly 1. The components in this application are connected by bolts, facilitating disassembly and maintenance, thus solving the problem of… Figure 1 The heat exchanger furnace with combustion chamber shown adopts an integrated welded structure, which presents a technical challenge in terms of maintenance.

[0073] refer to Figure 4 As shown, the fire shield assembly 1 includes an inner cylinder 103 and an outer cylinder 104. An inner channel 101 is formed inside the inner cylinder 103, and an outer channel 102 is formed between the inner cylinder 103 and the outer cylinder 104. (Reference) Figure 3As shown, the air outlet housing 2 has a burner connection port 201 communicating with the inner channel 101 on one side, and a process air outlet 202 communicating with the outer channel 102 on the other side; the exhaust housing 3 has an exhaust port 301 on one side; the heat exchange duct assembly 4 is connected to the flame shield assembly 1 and the exhaust housing 3 respectively, and the heat exchange duct assembly 4 is connected to both the inner channel 101 and the outer channel 102. The heat exchange duct assembly 4 has a process air inlet 407 near the exhaust housing 3; Reference Figure 2 As shown, the heat exchange component 5 is located inside the heat exchange duct assembly 4, and one end of the heat exchange component 5 is connected to the exhaust port 301, while the other end is indirectly connected to the inner channel 101 through the heat exchange duct assembly 4. Through the above technical solution, the process air inlet 407 is positioned close to the exhaust housing 3, i.e., close to the exhaust port 301; the burner connection port 201 and the process air outlet 202 are both located in the exhaust housing 2, i.e., the process air outlet 202 is close to the flue gas inlet; under the above arrangement, the transmission direction of the process air is opposite to the transmission direction of the flue gas, forming a counter-current heat exchange. This allows the process air to exchange heat with the lower-temperature flue gas first when the temperature is lower, and then with the higher-temperature flue gas when the temperature is higher, always maintaining the temperature difference between the flue gas and the process air, thus improving heat exchange efficiency. Simultaneously, based on this design, the initial flue gas temperature does not need to be too high, only slightly higher than the final required process air temperature. Compared to the prior art where the initial flue gas temperature is much higher than the final required process air temperature, this can save considerable energy consumption. For example, to achieve a final process air temperature of 200 degrees Celsius, existing technologies require an initial flue gas temperature of 300 degrees Celsius or even higher to ensure that the flue gas temperature at the flue gas outlet is greater than the process air temperature. However, with the solution proposed in this application, the initial flue gas temperature only needs to be set to 220 degrees Celsius to meet the requirements.

[0074] In some embodiments, the first end of the inner cylinder 103 is connected and fixed to the inner wall of the air outlet housing 2 on the side where the burner connection port 201 is located, and the first end of the outer cylinder 104 is connected and fixed to the outer wall of the air outlet housing 2 on the side away from the burner connection port 201. By adopting the above technical solution, the flue gas passage and the process air passage at the fire shield assembly 1 can be separated, so that the flue gas is confined in the inner passage 101 and the process air is confined in the outer passage 102, avoiding the mixing and interference between the two.

[0075] refer to Figure 4 and Figure 5As shown, in some embodiments, a spiral guide vane 105 is provided between the inner cylinder 103 and the outer cylinder 104, with the guide direction of the spiral guide vane 105 facing the air outlet casing 2. Through this technical solution, the spiral guide vane 105 can effectively reduce the flow resistance and allow the process air to flow spirally along the outer wall of the inner cylinder 103, resulting in a uniform flow velocity distribution and sufficient contact between the process air and the outer wall of the inner cylinder 103, thus effectively improving heat exchange efficiency. This arrangement can solve problems such as... Figure 1 In the heat exchanger furnace with combustion chamber shown, the combustion chamber ( Figure 1 The left side has a large windbreak area, and the flue gas circulates inside the combustion chamber outside the cylinder before flowing out from the right side, which can easily create localized high temperature / overheating zones. This issue can also be addressed. Figure 1 The problem of uneven downstream flow field, low air volume in the low-speed zone, short residence time in the high-speed zone, and low heat exchange efficiency in the process air after passing through the outer shell of the combustion chamber.

[0076] refer to Figure 6 and Figure 7 As shown, in some embodiments, the outer wall of the air outlet housing 2 on the side away from the burner connection port 201 is provided with a first through hole 203 communicating with the outer cylinder 104, and the air outlet housing 2 is also provided with a third air passage hole 204 for communicating with the flue gas housing 3. The burner connection port 201, process air outlet 202, first through hole 203 and third air passage hole 204 on the air outlet housing 2 are located on different surfaces, and the internal space of the air outlet housing 2 is divided into a flue gas passage space and a process air passage space by the inner cylinder 103, and the two do not interfere with each other.

[0077] refer to Figure 8As shown, in some embodiments, the heat exchange duct assembly 4 includes a first duct housing 401 and a second duct housing 402. The first duct housing 401 and the second duct housing 402 are vertically integrated and form an L-shape. The opening side of the first duct housing 401 is connected to the exhaust housing 3, and the process air inlet 407 is located on the first duct housing 401 near the opening side. An isolation plate 403 is provided inside the second duct housing 402, dividing the second duct housing 402 into two parts: the part closer to the first duct housing 401 communicates with the first duct housing 401 and serves as the process air passage, while the part farther from the first duct housing 401 serves as the flue gas passage. The isolation plate 403 separates the process air passage and the flue gas passage to prevent crosstalk. Specifically, the lower half of the isolation plate 403 is provided with a second through hole 404, and the second end of the inner cylinder 103 is fixed to the isolation plate 403 and communicates with the second through hole 404; the upper half of the isolation plate 403 is provided with a plurality of first smoke passage holes 405, part of the heat exchange component 5 is disposed in the first air duct shell 401, and the other part is disposed in the second air duct shell 402 and communicates with the first smoke passage holes 405; the second air duct shell 402 is provided with a third through hole 406, and the second end of the outer cylinder 104 is fixed to the second air duct shell 402 and communicates with the third through hole 406. Through the above-mentioned through hole arrangement and component connection arrangement, the process air duct and the flue gas duct are separated to avoid mixing and interference between the two.

[0078] refer to Figure 9As shown, in some embodiments, the heat exchange assembly 5 includes a plurality of heat exchange tubes 501, with each pair of adjacent heat exchange tubes 501 arranged in a staggered manner to achieve a triangular arrangement between adjacent heat exchange tubes 501, resulting in high heat transfer efficiency. The through holes at both ends of the heat exchange tubes 501 are respectively connected to the first smoke passage 405 and the second smoke passage 302. Flue gas enters the interior of the heat exchange tube 501 through the first smoke passage 405 and flows out into the exhaust housing 3 through the second smoke passage 302. Preferably, the heat exchange tubes 501 are provided with a vertically arranged first baffle 502 and a second baffle 503. There is a gap between the first baffle 502 and the lower inner wall of the first air duct housing 401, and a gap between the second baffle 503 and the upper inner wall of the first air duct housing 401. The process air inlet 407, the first baffle 502, and the second baffle 503 are arranged sequentially in the horizontal direction. Through the above technical solution, after the process air enters from the process air inlet 407, it first moves downward along the space to the left of the first baffle 502, then enters the space between the first baffle 502 and the second baffle 503 through the gap below the first baffle 502 and moves upward, and finally moves downward along the space to the right of the second baffle 503. This achieves a double 180° reversal baffle design, which effectively improves the uniformity of the wind speed distribution of the process air at the heat exchange tube 501 and ensures sufficient contact between the process air and the heat exchange tube 501, thereby improving the heat exchange efficiency.

[0079] refer to Figure 10 and Figure 11 As shown, in some embodiments, the exhaust housing 3 has a plurality of second smoke passage holes 302 on the side opposite to the exhaust port 301. The heat exchange component 5 is connected to the second smoke passage holes 302. The flue gas inside the heat exchange component 5 can reach the exhaust housing 3 through the second smoke passage holes 302 and then be discharged from the exhaust port 301.

[0080] Existing heat exchangers with combustion chambers suffer from heat transfer lag, resulting in long response times and poor temperature control accuracy for process air temperature regulation. This application provides a solution to this problem. (Reference) Figure 11As shown, in some embodiments, the exhaust housing 3 may also be provided with a process air branch channel for adjusting the final temperature of the process air; specifically, the exhaust housing 3 is provided with a first air passage 303 and a second air passage 304. The first air passage 303 is connected to the heat exchange duct assembly 4, and the second air passage 304 is connected to the third air passage 204 of the outlet housing 2, thereby forming a process air branch channel from the heat exchange duct assembly 4 directly through the exhaust housing 3 to the outlet housing 2. The branch process air in this channel is not heated by the heat exchange assembly 5 and the fire shield assembly 1, so its temperature will be lower. By mixing this part of the process air with another part of the heated process air, the temperature of the final process air can be adjusted. In addition, a baffle 305 is provided inside the smoke exhaust housing 3, which divides the smoke exhaust housing 3 into a first part and a second part. The smoke exhaust port 301 and the second smoke passage hole 302 are provided on the first part, and the first air passage hole 303 and the second air passage hole 304 are provided on the second part. The above arrangement divides the smoke exhaust housing 3 into two parts: the first part is used for smoke exhaust, and the second part is used for process air diversion to prevent crosstalk between smoke and process air. Furthermore, in order to achieve precise temperature control, an air regulating component 6 is provided at the second air passage hole 304, which is used to adjust the opening degree of the second air passage hole 304. Through the above technical solution, a portion of the process air can directly reach the outlet housing 2 through the second part of the exhaust housing 3, and then merge with another portion of the process air heated by flue gas before flowing out from the process air outlet 202. At the same time, the opening of the second air passage 304 is designed to be adjustable, so that the flow rate of the process air passing through the second part of the exhaust housing 3 is controllable, thereby realizing the temperature regulation of the final output process air. This method can effectively eliminate the heat transfer lag of indirect heating, achieve rapid temperature control, and achieve high temperature control accuracy.

[0081] refer to Figure 12As shown, in some embodiments, the air conditioning assembly 6 includes an air conditioning housing 601, multiple blades 602, and a drive motor 603. The blades 602 are rotatably connected to the air conditioning housing 601 via a rotating shaft 604. A first connecting piece 605 is provided on the rotating shaft 604, and the first connecting piece 605 and the rotating shaft 604 can be fixedly connected. The multiple first connecting pieces 605 are connected to each other via second connecting pieces 606, and the first connecting pieces 605 and the second connecting pieces 606 are hinged by a pin. The output end of the drive motor 603 is fixedly connected to one of the rotating shafts 604. Through the above technical solution, the drive motor 603 can drive one of the rotating shafts 604 to rotate, thereby driving the first connecting piece 605 connected to it to rotate. Thus, through the second connecting piece 606, all the first connecting pieces 605 and all the rotating shafts 604 rotate synchronously, realizing the angle adjustment of the blades 602, that is, realizing the opening adjustment of the second air passage 304.

[0082] Based on the above structural setup, the flow of process air and flue gas within it will be further explained below.

[0083] refer to Figure 13 As shown, the flue gas along Figure 13 Following the direction of the dashed arrow, after the burner is connected to the burner connection port 201, the generated high-temperature flue gas flows to the right along the inner channel 101. Upon reaching the heat exchange duct assembly, the flue gas flows upward along the right side of the isolation plate 403, and after reaching the heat exchange tube 501, it flows to the left along the inside of the heat exchange tube 501, finally exiting from the exhaust port 301 of the exhaust shell 3. Simultaneously, the process air flows along... Figure 13 The solid arrow points in the direction of the process air. After entering through the process air inlet 407, the process air splits into two routes. The main route moves downwards and then moves to the right along the bottom of the first baffle 502, turning upwards. It then moves to the right along the second baffle 503, turning downwards, and moves downwards along the space to the left of the partition plate 403 to the outer surface of the inner cylinder 103. It then moves to the left along the spiral guide vane 105 and finally reaches the outlet housing 2. The branch route moves downwards and then enters the lower half of the exhaust housing 3 to the left. After being adjusted by the air regulating component 6, it moves downwards into the outlet housing 2, mixes with the main route, and is discharged from the process air outlet 202.

[0084] In the above process, the main process air path first exchanges heat with the flue gas through multiple heat exchange tubes 501, and then through the inner cylinder 103. The flue gas temperature is lower at the heat exchange tubes 501 and higher at the inner cylinder 103, making the process air heat exchange more convenient and efficient, and requiring less initial flue gas temperature. In addition, the two heat exchange zones are designed with 180-degree baffles and spiral guides, respectively, which can make the flow velocity distribution of the process air uniform and effectively improve the heat exchange efficiency. At the same time, by adjusting the flow rate of the low-temperature process air mixed with the main path through the process air branch, the temperature of the final process air can be regulated, which can effectively eliminate the heat transfer lag of indirect heating, achieve rapid temperature control, and achieve high temperature control accuracy.

[0085] In summary, the embodiments of this application have the following advantages: high heat exchange efficiency, reaching 85%~88%, and excellent energy-saving effect; low combustion system resistance, with combustion flue gas pressure loss ≤300Pa; the pressure head margin of the burner's integrated fan can overcome the exhaust resistance, eliminating the need for an additional exhaust fan; low process air pressure loss, meeting the requirements of most industries and operating conditions; with the temperature control valve closed, the process air pressure loss is ≤800Pa, and it will further decrease during the operation of the temperature control valve; and a multi-section detachable design, facilitating inspection and maintenance.

[0086] Example 2

[0087] Based on the indirect heating furnace provided in Example 1, this example provides a method for indirectly heating process air, such as... Figure 14 As shown, the method includes the following steps:

[0088] Step 101: The burner is positioned at the burner connection port 201, allowing the high-temperature flue gas generated by the burner to sequentially pass through the inner channel 101 of the fire shield assembly 1, the inner channel of the heat exchange duct assembly 4, and the inner channel of the heat exchange assembly 5, before being discharged from the exhaust port 301 of the exhaust housing 3. In this step, the inner channel of the heat exchange duct assembly 4 refers to... Figure 13 The right-side channel of the middle isolation plate 403 and the internal channel of the heat exchange component 5 refer to the internal channel of the heat exchange tube 501.

[0089] Step 102: The process air enters through the process air inlet 407 of the heat exchange duct assembly 4. The first part of the process air passes sequentially through the outer surface of the heat exchange component 5, the internal channel of the heat exchange duct assembly 4, and the outer channel 102 of the fire shield assembly 1 before entering the outlet housing 2. In this step, the outer surface of the heat exchange component 5 refers to the outer surface of the heat exchange tube 501, and the internal channel of the heat exchange duct assembly 4 refers to... Figure 13 The left-side passage of the central isolation panel 403; in addition, the wind route during this step is the main route.

[0090] Step 103: The second part of the process air enters the exhaust housing 3, and after its flow rate is adjusted by the air regulating component 6, it enters the exhaust housing 2, mixes with the first part of the process air in the exhaust housing 2, and is discharged from the process air outlet 202. The process air in this step follows a branch route.

[0091] By adopting the above technical solution, the transmission direction of the process air is opposite to that of the flue gas, forming a counter-current heat exchange, which improves heat exchange efficiency and saves energy. At the same time, by adjusting the flow rate of the branch process air, the heat transfer lag of indirect heating is eliminated, achieving rapid temperature control with high temperature control accuracy.

[0092] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An indirect heating furnace, characterized in that, It includes a fire shield assembly (1), an air outlet shell (2), a smoke exhaust shell (3), a heat exchange duct assembly (4), and a heat exchange assembly (5), wherein: The fire shield assembly (1) includes an inner channel (101) and an outer channel (102). The air outlet housing (2) has a burner connection port (201) on one side that communicates with the inner channel (101), and a process air outlet (202) on the other side that communicates with the outer channel (102). A smoke exhaust port (301) is provided on one side of the smoke exhaust housing (3); The heat exchange duct assembly (4) is connected to the fire shield assembly (1) and the smoke exhaust shell (3) respectively. The heat exchange duct assembly (4) is connected to both the inner channel (101) and the outer channel (102). The heat exchange duct assembly (4) is provided with a process air inlet (407) near the smoke exhaust shell (3). The heat exchange component (5) is located inside the heat exchange duct component (4), and one end of the heat exchange component (5) is connected to the smoke exhaust port (301), and the other end is connected to the inner channel (101); The fire shield assembly (1) includes an inner cylinder (103) and an outer cylinder (104). An inner channel (101) is formed inside the inner cylinder (103), and an outer channel (102) is formed between the inner cylinder (103) and the outer cylinder (104). The first end of the inner cylinder (103) is connected and fixed to the inner wall of the air outlet housing (2) on the side where the burner connection port (201) is provided. The first end of the outer cylinder (104) is connected and fixed to the outer wall of the air outlet housing (2) on the side away from the burner connection port (201). A first through hole (203) communicating with the outer cylinder (104) is provided on the outer wall of the air outlet housing (2) on the side away from the burner connection port (201). The heat exchange duct assembly (4) includes a first duct housing (401) and a second duct housing (402), which are arranged vertically. The second air duct housing (402) is provided with an isolation plate (403), the isolation plate (403) is provided with a second through hole (404) and a plurality of first smoke passage holes (405), and the second air duct housing (402) is provided with a third through hole (406). The heat exchange component (5) is partially disposed in the first air duct housing (401) and partially disposed in the second air duct housing (402) and communicates with the first smoke passage (405); The second end of the inner cylinder (103) is fixed to the isolation plate (403) and communicates with the second through hole (404), and the second end of the outer cylinder (104) is fixed to the second air duct shell (402) and communicates with the third through hole (406); The exhaust housing (3) has a plurality of second smoke passage holes (302) on the side opposite to the exhaust port (301), and the heat exchange component (5) is connected to the second smoke passage holes (302); The exhaust housing (3) is provided with a first air passage hole (303) and a second air passage hole (304), and the exhaust housing (2) is provided with a third air passage hole (204). The first air passage hole (303) is connected to the heat exchange duct assembly (4), and the second air passage hole (304) is connected to the third air passage hole (204). The smoke exhaust housing (3) is provided with a baffle (305) inside, which divides the smoke exhaust housing (3) into a first part and a second part. The smoke exhaust port (301) and the second smoke passage hole (302) are provided on the first part, and the first air passage hole (303) and the second air passage hole (304) are provided on the second part. An air regulating component (6) is provided at the second air passage (304), and the air regulating component (6) is used to adjust the opening degree of the second air passage (304).

2. The indirect heating furnace according to claim 1, characterized in that, A spiral guide vane (105) is provided between the inner cylinder (103) and the outer cylinder (104).

3. The indirect heating furnace according to claim 1, characterized in that, The heat exchange assembly (5) includes several heat exchange tubes (501), with each pair of adjacent heat exchange tubes (501) arranged in a staggered and parallel manner.

4. The indirect heating furnace according to claim 3, characterized in that, The heat exchange tube (501) is provided with a first baffle plate (502) and a second baffle plate (503). There is a gap between the first baffle plate (502) and the lower inner wall of the first air duct shell (401), and there is a gap between the second baffle plate (503) and the upper inner wall of the first air duct shell (401).

5. The indirect heating furnace according to claim 1, characterized in that, The air conditioning assembly (6) includes an air conditioning housing (601), multiple blades (602), and a drive motor (603). The blade (602) is rotatably connected to the air conditioning housing (601) via a rotating shaft (604). A first connecting piece (605) is provided on the rotating shaft (604), and multiple first connecting pieces (605) are connected to each other via second connecting pieces (606). The output end of the drive motor (603) is fixedly connected to one of the rotating shafts (604).

6. A method for indirectly heating process air, applied to the indirect heating furnace according to any one of claims 1-5, characterized in that, include: The burner is set at the burner connection port (201), so that the flue gas generated by the burner passes through the inner channel (101) of the fire shield assembly (1), the inner channel of the heat exchange air duct assembly (4) and the inner channel of the heat exchange assembly (5) in sequence, and is discharged from the flue gas outlet (301) of the flue gas shell (3). The process air enters from the process air inlet (407) of the heat exchange duct assembly (4), passes through the outer surface of the heat exchange assembly (5), the internal channel of the heat exchange duct assembly (4), and the outer channel (102) of the fire shield assembly (1) in sequence, and is discharged from the process air outlet (202) of the air outlet shell (2).

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