Wood chip-fired medium temperature indirect heat exchanger hot blast stove

Abstract

The utility model relates to a boiler technical field, concretely is a kind of wood chip medium temperature indirect heat exchange hot blast furnace, including heat exchange equipment, and the one end of heat exchange equipment is connected with combustion equipment through connecting flue, and combustion equipment includes shell, and the inside of shell is provided with combustion chamber, and heat exchange equipment includes heat exchange bin, and the inside of heat exchange bin is installed with several heat exchange pipes, and the flue gas generated by combustion equipment enters heat exchange equipment through connecting flue, and carries out heat exchange with heat exchange pipe.This wood chip medium temperature indirect heat exchange hot blast furnace, the front arch, rear arch of the setting in combustion equipment and the folding smoke wall form optimized combustion space, and the front arch can reflect heat to fuel layer, accelerate wood chip ignition and combustion speed, and the rear arch prolongs the residence time of flue gas in combustion chamber, cooperates with the support and ventilation design of grate, ensures that wood chip is fully combusted, reduces unburnt residue, significantly improves fuel utilization.

Description

Technical Field

[0001] This utility model relates to the field of boiler technology, and more specifically, to a wood chip-fired medium-temperature indirect heat exchange hot air furnace. Background Technology

[0002] In current industrial production and material drying, hot air furnaces are widely used as key heating equipment. Among many related technologies, Chinese patent CN212930904U discloses a hot air furnace for wood chip drying, which to some extent achieves the heating function for wood chip drying. However, it has obvious shortcomings. For example, in terms of combustion equipment, its structural design fails to fully consider efficient fuel combustion and reasonable flue gas flow. The furnace may lack structures such as the front arch, rear arch, and flue gas deflector wall as described in this invention, resulting in incomplete fuel combustion, a large amount of energy not being effectively released, and low thermal efficiency. At the same time, the flow path of flue gas in the furnace is unreasonable, which can easily lead to localized excessively high or low temperatures, affecting the overall heat exchange effect.

[0003] For example, Chinese patent CN219433504U discloses a heat exchange hot air furnace that facilitates ash removal, focusing on improvements in ash removal. However, it has deficiencies in the overall layout of the heat exchange equipment and its coordination with the combustion equipment. Its heat exchange tubes may not be arranged as efficiently as in this invention, failing to fully utilize the heat in the flue gas and resulting in low hot air output efficiency, making it difficult to meet the demands of large-scale, high-efficiency production. Utility Model Content

[0004] The purpose of this invention is to provide a wood chip-fired medium-temperature indirect heat exchange hot air furnace to solve the problems mentioned in the background art that fail to fully consider the efficient combustion of fuel and the reasonable flow of flue gas.

[0005] To achieve the above objectives, this utility model provides a wood chip medium-temperature indirect heat exchange hot air furnace, including a heat exchange device. One end of the heat exchange device is connected to a combustion device via a connecting flue. The combustion device includes a shell, and a combustion chamber is provided inside the shell. The heat exchange device includes a heat exchange chamber, and a plurality of heat exchange tubes are installed inside the heat exchange chamber. The flue gas generated by the combustion device enters the heat exchange device through the connecting flue and exchanges heat with the heat exchange tubes.

[0006] This setup connects the combustion equipment and the heat exchange equipment via a connecting flue. The combustion chamber of the combustion equipment generates high-temperature flue gas, which enters the heat exchange tubes of the heat exchange equipment through the connecting flue and undergoes indirect heat exchange with the air outside the heat exchange tubes.

[0007] Preferably, a grate is installed at the bottom of the combustion chamber, a front arch is installed at the upper front of the combustion chamber, a rear arch is installed at the upper rear of the combustion chamber, and a feed hopper is installed at one end of the heat exchanger.

[0008] This feature includes a grate that supports the wood chips and provides the necessary ventilation space for combustion; a front arch that reflects heat to the fuel layer, accelerating the ignition of the wood chips; a rear arch that extends the residence time of flue gas in the combustion chamber, promoting complete combustion of the fuel; and a feed hopper that allows for continuous or intermittent feeding of wood chips, ensuring combustion stability.

[0009] Preferably, a smoke deflector is installed on the upper interior of the outer casing.

[0010] This feature, the smoke deflector wall, is located inside the upper part of the casing. It alters the flow path of the flue gas within the combustion chamber, prolongs the residence time of the flue gas, and guides the flue gas to gather towards the connecting flue.

[0011] Preferably, the outer shell has a slag discharge port on its side wall near the smoke deflector wall, and a slag removal machine is connected to the outside of the slag discharge port.

[0012] This feature allows the residue generated during combustion to accumulate at the ash discharge port under the guidance of the smoke deflector wall, and the ash removal machine promptly discharges the residue from the combustion chamber through the ash discharge port.

[0013] Preferably, the heat exchanger has two heat exchange chambers inside. The upper end of the heat exchange tube is connected to a flue gas inlet, which is connected to a flue. The lower end of the heat exchange tube is connected to a flue gas outlet. Flue gas enters the heat exchange tube from the flue gas inlet for heat exchange and is discharged from the flue gas inlet.

[0014] This design incorporates two heat exchange chambers to increase the heat exchange area. Flue gas enters the heat exchange tube from the upper flue gas inlet, exchanges heat with the air outside the tube during its flow inside the tube, and finally exits from the lower flue gas outlet.

[0015] Preferably, the heat exchange chamber is provided with a cold air inlet at one end and a hot air outlet at the other end. External cold air enters from the cold air inlet, passes through the outside of the heat exchange tube, exchanges heat with the high-temperature flue gas inside the heat exchange tube, and is discharged from the hot air outlet.

[0016] In this configuration, cold air enters the heat exchange chamber through the cold air inlet, absorbs heat from the high-temperature flue gas inside the heat exchange tubes as it flows outside the tubes, and is then discharged from the hot air outlet after being heated.

[0017] Preferably, both the upper and lower ends of the heat exchange tube are provided with flue gas buffer cavities, and the outer sides of the upper and lower cavities are respectively provided with upper slag removal ports and lower slag removal ports.

[0018] This feature includes cavities at the top and bottom of the heat exchange tubes to buffer the flow velocity of the flue gas and reduce turbulence resistance; the upper and lower slag removal ports can be used to periodically clean the accumulated soot and residue inside the heat exchange tubes.

[0019] This foundation provides stable support for the combustion equipment and disperses vibration and weight loads during equipment operation.

[0020] Preferably, the combustion device is mounted on a foundation at its bottom.

[0021] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0022] In this wood chip indirect heat exchange hot air furnace, the front arch, rear arch, and smoke deflector wall in the combustion equipment form an optimized combustion space. The front arch can reflect heat to the fuel layer, accelerating the ignition and combustion speed of the wood chips, while the rear arch extends the residence time of flue gas in the combustion chamber. Combined with the support and ventilation design of the grate, it ensures that the wood chips are fully burned, reduces unburned residue, and significantly improves fuel utilization.

[0023] The system employs an indirect heat exchange mode, where high-temperature flue gas flows inside the heat exchange tubes while cold air passes outside, preventing direct contact between the two. This avoids impurities such as dust and tar in the flue gas from mixing with the hot air, thus solving the problem of contaminating materials in direct heat exchange equipment. The hot air outlet temperature is stably controlled at ≤200℃, meeting the cleanliness and temperature accuracy requirements of medium-temperature drying processes, and is particularly suitable for drying materials sensitive to impurities, such as grains and medicinal herbs.

[0024] The heat exchanger is equipped with two heat exchange chambers and multiple sets of heat exchange tubes, increasing the heat exchange area. Flue gas enters the heat exchange tubes from the upper flue gas inlet, while cold air enters the heat exchange chamber from the cold air inlet. Through counter-current or cross-current heat exchange, the heat exchange efficiency between the high-temperature flue gas and the cold air is enhanced. At the same time, the flue gas buffer cavities at the upper and lower ends of the heat exchange tubes reduce flue gas flow resistance, making heat exchange more uniform and further improving heat utilization.

[0025] The upper and lower slag removal ports at the top and bottom of the heat exchange tubes allow for regular cleaning of accumulated soot inside the tubes, preventing ash buildup from affecting heat exchange efficiency. The slag remover connected to the side of the combustion equipment promptly removes combustion residue from the grate, reducing the impact of slag accumulation on the grate and combustion. This design solves the problems of difficult ash removal and efficiency reduction caused by slag accumulation in existing equipment, lowers maintenance costs, and extends the continuous operating time and overall service life of the equipment. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0027] Figure 2 This is a top view of the structure of this utility model;

[0028] Figure 3 This is a schematic diagram of the external structure of the heat exchanger in this utility model;

[0029] Figure 4 This is a schematic diagram of the internal structure of the heat exchanger in this utility model;

[0030] Figure 5 This is a schematic diagram of the combustion device in this utility model;

[0031] The meanings of the labels in the diagram are as follows:

[0032] 1. Heat exchange equipment; 11. Heat exchange chamber; 12. Heat exchange tube; 13. Cold air inlet; 14. Hot air outlet; 15. Flue gas inlet; 16. Flue gas outlet; 17. Upper slag removal port; 18. Lower slag removal port; 2. Connecting flue; 3. Foundation; 4. Combustion equipment; 41. Shell; 42. Combustion chamber; 43. Grate; 44. Flush wall; 45. Feed hopper; 46. Rear arch; 47. Front arch; 5. Slag remover. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] This utility model provides a wood chip-fired medium-temperature indirect heat exchange hot air furnace, such as... Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, the device includes a heat exchanger 1. One end of the heat exchanger 1 is connected to a combustion device 4 via a connecting flue 2. The combustion device 4 includes a housing 41, and a combustion chamber 42 is provided inside the housing 41. The heat exchanger 1 includes a heat exchange chamber 11, and a plurality of heat exchange tubes 12 are installed inside the heat exchange chamber 11. The flue gas generated by the combustion device 4 enters the heat exchanger 1 through the connecting flue 2 and exchanges heat with the heat exchange tubes 12.

[0035] The heat exchanger 1 and the combustion device 4 are connected by a flue 2. Inside the combustion chamber 42 of the outer shell 41 of the combustion device 4, wood chips burn to produce high-temperature flue gas. This flue gas enters the heat exchange tube 12 of the heat exchanger 1 through the flue 2, where it indirectly exchanges heat with the outside air through the tube wall. This achieves independent separation between the combustion system and the heat exchange system, preventing dust, tar, and other impurities in the flue gas from contaminating the hot air and ensuring the cleanliness of the hot air. The heat exchange tube 12, as the core heat exchange component, provides an efficient path for heat transfer, laying the foundation for medium-temperature hot air output.

[0036] In this embodiment, as Figure 5As shown, a grate 43 is installed at the bottom of the combustion chamber 42, a front arch 47 is installed at the front of the upper part of the combustion chamber 42, a rear arch 46 is installed at the rear of the upper part of the combustion chamber 42, and a feed hopper 45 is installed at one end of the heat exchange device 1.

[0037] The grate 43 at the bottom of the combustion chamber 42 supports the wood chips and provides ventilation gaps to ensure oxygen supply for combustion. The front arch 47 at the top reflects heat to the fuel layer, accelerating the ignition of the wood chips. The rear arch 46 at the top extends the residence time of flue gas in the combustion chamber 42, promoting complete combustion of fuel. The feed hopper 45 supplies wood chips to the combustion chamber 42 in a measured amount to maintain continuous combustion. The ventilation design of the grate 43, combined with the heat reflection and flue gas guidance of the front arch 47 and rear arch 46, significantly improves the combustion efficiency of wood chips and reduces unburned materials. The feed hopper 45 ensures a stable fuel supply, avoids combustion interruption, and ensures stable temperature within the combustion chamber 42.

[0038] Specifically, such as Figure 5 As shown, a smoke deflector wall 44 is installed on the upper part of the interior of the outer casing 41.

[0039] The flue wall 44 inside the outer casing 41 alters the flow trajectory of the flue gas within the combustion chamber 42, forcing the flue gas to detour, extending its residence time in the high-temperature zone, and guiding the flue gas to gather towards the connecting flue 2. By extending the flue gas residence time, it promotes the secondary combustion of unburned components in the flue gas, improving fuel utilization; at the same time, it optimizes the flue gas flow direction, reduces short-circuit losses, and ensures that more heat enters the heat exchanger 1 through the connecting flue 2.

[0040] Furthermore, such as Figure 5 As shown, a slag discharge port is provided on the side wall of the outer shell 41 near the smoke deflector wall 44, and a slag removal machine 5 is connected to the outside of the slag discharge port.

[0041] The slag produced during combustion is guided by the flue wall 44 and collects at the slag discharge port on the side wall of the outer shell 41. The slag remover 5 promptly discharges the slag outside the combustion chamber 42 through the slag discharge port. This prevents slag from accumulating on the grate 43 or at the bottom of the combustion chamber 42, thus preventing blockage of ventilation gaps or affecting fuel combustion conditions, reducing manual slag removal costs, and ensuring the long-term stable operation of the combustion equipment 4.

[0042] Furthermore, such as Figure 3 , Figure 4 As shown, the heat exchanger 1 has two heat exchange chambers inside. The upper end of the heat exchange tube 12 is connected to the flue gas inlet 15, which is connected to the flue duct 2. The lower end of the heat exchange tube 12 is connected to the flue gas outlet 16. The flue gas enters the heat exchange tube 12 from the flue gas inlet 15 for heat exchange and is discharged from the flue gas inlet 15.

[0043] The two heat exchange chambers within heat exchanger 1 expand the heat exchange area. The flue gas inlet 15 at the upper end of the heat exchange tube 12 connects to the connecting flue duct 2 to receive high-temperature flue gas. The flue gas releases heat during its flow within the heat exchange tube 12 and is finally discharged from the flue gas outlet 16 at the lower end. The multiple heat exchange chambers and the densely arranged heat exchange tubes 12 increase the heat exchange contact area. The directional flow of flue gas from the inlet to the outlet ensures uniform heat exchange and improves heat utilization. The clearly defined flue gas inlet and outlet paths reduce flow resistance and ensure stable heat exchange efficiency.

[0044] Furthermore, such as Figure 3 , Figure 4 As shown, one end of the heat exchange chamber 11 is provided with a cold air inlet 13 and the other end is provided with a hot air outlet 14. External cold air enters from the cold air inlet 13, passes through the outside of the heat exchange tube 12, exchanges heat with the high-temperature flue gas inside the heat exchange tube 12, and is discharged from the hot air outlet 14.

[0045] External cold air enters through the cold air inlet 13 of the heat exchange chamber 11. As it flows outside the heat exchange tubes 12, it absorbs heat from the high-temperature flue gas inside the tubes 12 through the tube walls. The heated air is then discharged from the hot air outlet 14. The cold air and the high-temperature flue gas form a highly efficient counter-current or cross-current heat exchange within the heat exchange chamber 11, ensuring that the cold air fully absorbs heat and stably outputs medium-temperature hot air with a temperature ≤200℃, meeting the heat source temperature requirements of the drying process.

[0046] Furthermore, such as Figure 3 , Figure 4 As shown, both the upper and lower ends of the heat exchange tube 12 are provided with flue gas buffer cavities, and the outer sides of the upper and lower cavities are respectively provided with upper slag removal port 17 and lower slag removal port 18.

[0047] The flue gas buffer cavities at both ends of the heat exchange tube 12 reduce the flue gas flow velocity and minimize turbulence. The upper slag removal port 17 and lower slag removal port 18 on the outer side of the upper and lower cavities can be opened periodically to remove accumulated soot and residue inside the heat exchange tube 12. The buffer cavities make the flue gas flow more stable and improve heat exchange uniformity. The slag removal port design facilitates timely cleaning of ash accumulation inside the heat exchange tube 12, preventing ash layers from hindering heat transfer, maintaining long-term efficient heat exchange, and reducing maintenance difficulty.

[0048] Furthermore, such as Figure 1 As shown, a foundation 3 is installed at the bottom of the combustion device 4.

[0049] The foundation 3 at the bottom of the combustion device 4 provides rigid support to distribute the weight of the device and the vibration load during operation, thus fixing the installation position of the combustion device 4. This enhances the overall stability of the combustion device 4, prevents the connection flue 2 from failing to seal or components from loosening due to vibration during operation, extends the service life of the device, and improves operational safety.

[0050] In operation, the wood chip medium-temperature indirect heat exchange hot air stove of this invention first feeds wood chip fuel into the combustion chamber 42 of the combustion device 4 through the feed hopper 45, and then falls onto the grate 43 to form a uniform fuel layer. Before ignition, the ventilation gaps of the grate 43 and the integrity of the front arch 47 and rear arch 46 are checked. After the igniter burns in the center of the grate 43, wood chips are manually added and the blower is turned on, utilizing the ventilation below the grate 43 to provide sufficient oxygen for the fuel. The front arch 47 reflects heat to the surface of the fuel layer, accelerating the ignition of the wood chips; the rear arch 46 guides the flame to extend backward, allowing the fuel layer to burn gradually from the front to the rear, forming a stable combustion zone.

[0051] The wood chips burn completely in the combustion chamber 42, and the resulting high-temperature flue gas flows upward under the action of the blower and induced draft fan. The flue gas deflector 44 inside the outer shell 41 changes the direction of the flue gas flow, forcing the flue gas to detour and prolonging its residence time in the combustion chamber 42, so that unburned flue gas components are further burned in the high-temperature zone, improving fuel utilization. At the same time, the flue gas deflector 44 guides the flue gas to gather towards the connecting flue 2, reducing heat loss. The ash produced by combustion moves towards the ash discharge port under the influence of the flue gas, and is finally discharged in time by the ash remover 5 to prevent the grate 43 from clogging.

[0052] High-temperature flue gas enters the flue gas inlet 15 of heat exchanger 1 through connecting flue 2, and then flows into the heat exchange tubes 12 of the two heat exchange chambers. Flue gas buffer cavities at the upper and lower ends of the heat exchange tubes 12 reduce the flue gas flow velocity, allowing the flue gas to flow smoothly within the tubes and fully contact the air outside. As the flue gas flows downwards within the heat exchange tubes 12, it transfers heat to the cold air outside the tubes through the tube walls, gradually reducing its own temperature, and finally exits from the flue gas outlet 16 at the lower end.

[0053] External cold air enters from the cold air inlet 13 of the heat exchange chamber 11, forming a circulating flow outside the heat exchange tube 12. It then undergoes efficient counter-current or cross-current heat exchange with the high-temperature flue gas inside the tube through the tube wall. After absorbing heat, the cold air's temperature rises, eventually forming medium-temperature hot air with a temperature ≤200℃, which is discharged from the hot air outlet 14, providing a clean heat source for the drying process.

[0054] During operation, a small amount of soot will accumulate inside the heat exchange tube 12. This can be cleaned periodically through the upper ash removal port 17 and lower ash removal port 18 on the outer side of the upper and lower cavities to prevent ash accumulation from affecting heat exchange efficiency. The foundation 3 at the bottom of the combustion equipment 4 provides rigid support to distribute the equipment load, reduce the impact of vibration on the connecting flue 2 and various components, and ensure the long-term stable operation of the entire system.

[0055] Finally, it should be noted that the electronic components in the combustion device 4 and other components in this embodiment are all general standard parts or parts known to those skilled in the art. Their structure and principle can be known to those skilled in the art through technical manuals or conventional experimental methods. In the idle part of this device, all the above-mentioned electrical components are connected by wires. The specific connection method should refer to the working order between each electrical component in the above working principle to complete the electrical connection. All of these are technologies known in the art.

[0056] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A wood-burning, medium-temperature, indirect heat exchange hot air furnace, comprising heat exchange equipment (1), characterized in that: One end of the heat exchange device (1) is connected to a combustion device (4) via a connecting flue (2). The combustion device (4) includes a shell (41) and a combustion chamber (42) is provided inside the shell (41). The heat exchange device (1) includes a heat exchange chamber (11) and a plurality of heat exchange tubes (12) are installed inside the heat exchange chamber (11). The flue gas generated by the combustion device (4) enters the heat exchange device (1) through the connecting flue (2) and exchanges heat with the heat exchange tubes (12).

2. The wood chip indirect heat exchange hot air furnace according to claim 1, characterized in that: A grate (43) is installed at the bottom of the combustion chamber (42), a front arch (47) is installed at the front of the upper part of the combustion chamber (42), a rear arch (46) is installed at the rear of the upper part of the combustion chamber (42), and a feed hopper (45) is installed at one end of the heat exchange device (1).

3. The wood chip indirect heat exchange hot air furnace according to claim 1, characterized in that: A smoke deflector (44) is installed on the upper interior of the outer casing (41).

4. The wood chip indirect heat exchange hot air furnace according to claim 3, characterized in that: The outer shell (41) has a slag discharge port on its side wall near the smoke deflector wall (44), and a slag remover (5) is connected to the outside of the slag discharge port.

5. The wood chip indirect heat exchange hot air furnace according to claim 1, characterized in that: The heat exchange device (1) has two heat exchange chambers inside. The upper end of the heat exchange tube (12) is connected to a flue gas inlet (15), which is connected to a connecting flue (2). The lower end of the heat exchange tube (12) is connected to a flue gas outlet (16). Flue gas enters the heat exchange tube (12) from the flue gas inlet (15) for heat exchange and is discharged from the flue gas inlet (15).

6. The wood chip indirect heat exchange hot air furnace according to claim 5, characterized in that: The heat exchange chamber (11) is provided with a cold air inlet (13) at one end and a hot air outlet (14) at the other end. External cold air enters from the cold air inlet (13), passes through the outside of the heat exchange tube (12), exchanges heat with the high temperature flue gas inside the heat exchange tube (12), and is discharged from the hot air outlet (14).

7. The wood chip indirect heat exchange hot air furnace according to claim 5, characterized in that: Both ends of the heat exchange tube (12) are provided with flue gas buffer cavities, and the outer sides of the upper and lower cavities are respectively provided with upper slag removal port (17) and lower slag removal port (18).

8. The wood chip indirect heat exchange hot air furnace according to claim 1, characterized in that: The bottom of the combustion device (4) is equipped with a foundation (3).

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