A belt-type induration machine with staged cooling and heat recovery

Abstract

The utility model discloses a kind of belt roasters of hierarchical cooling and heat energy recovery, improve the existing belt roaster baking section, soaking section and the technical problem such as air leakage between cooling section. The belt roaster includes sequentially arranged drying section, preheating section, baking section, soaking section, primary cooling section and secondary cooling section, further includes: protective partition, at least be set between the baking section with the soaking section, between the soaking section with the primary cooling section;Hot air duct, one end is connected to the top of the secondary cooling section, the other end is connected to the top of the soaking section, so that the hot air of the secondary cooling section can enter the soaking section. The utility model can realize hierarchical cooling and heat recycling, improve resource utilization efficiency, and also can improve the problem such as air leakage between baking section, soaking section and cooling section.

Description

Technical Field

[0001] This utility model belongs to the field of roasting machine technology, specifically relating to a belt roasting machine with staged cooling and heat recovery. Background Technology

[0002] The belt roaster completes the drying, preheating, roasting and cooling processes in one machine, which is arranged in a closed workshop. It has the advantages of short process, less heat dissipation, good heat recovery utilization, small footprint, high thermal efficiency and low overall energy consumption.

[0003] The belt calciner in the relevant technology usually includes a drying section, a preheating section, a calcining section, a homogenizing section and a cooling section arranged in sequence. Qualified green pellets enter from the head of the calciner and pass through the drying section, preheating section, calcining section, homogenizing section and cooling section in sequence. The pellet temperature is reduced to 120°C and discharged from the tail.

[0004] However, the heat energy in the various process sections of the belt calciner in the relevant technology is difficult to recover and utilize. In particular, the hot air formed after the air enters the cooling section and exchanges heat with the pellets is usually directly discharged, resulting in resource waste. At the same time, the calcination section, soaking section and cooling section are interconnected, which leads to air leakage problems and needs to be improved. Utility Model Content

[0005] In order to solve all or some of the above problems, the purpose of this utility model is to provide a belt roaster with staged cooling and heat recovery, which can realize staged cooling and heat recovery and utilization, improve resource utilization efficiency, and also improve the problem of air leakage between the roasting section, the soaking section and the cooling section.

[0006] This utility model provides a belt roaster with staged cooling and heat recovery, comprising a drying section, a preheating section, a roasting section, a homogenizing section, a primary cooling section, and a secondary cooling section arranged sequentially, and further comprising: A protective partition wall is provided at least between the calcination section and the homogenization section, and between the homogenization section and the primary cooling section; A hot air duct is connected at one end to the top of the secondary cooling section and at the other end to the top of the heat exchange section, so that hot air from the secondary cooling section can enter the heat exchange section.

[0007] Optionally, the drying section includes a forced-air drying section and an exhaust drying section, and protective partitions are also provided between the forced-air drying section and the exhaust drying section, and between the exhaust drying section and the preheating section.

[0008] Optionally, the primary cooling section includes a hot air cooling section and a warm air cooling section, and the protective partition is disposed between the heat equalization section and the hot air cooling section.

[0009] Optionally, the secondary cooling section includes a first air-cooled section and a second air-cooled section, and the protective partition wall is also provided between the first air-cooled section and the second air-cooled section.

[0010] Optionally, the belt roaster further includes: A ventilation drying oven hood is connected to the top of the ventilation drying section; The first roasting air box is connected to the bottom of the roasting section; A heat exchanger box is connected to the bottom of the heat exchanger section; The regenerating air duct is connected at one end to the first roasting air box and the homogenizing air box respectively, and at the other end to the exhaust drying furnace hood and the preheating section respectively. A regenerating air fan is connected to the regenerating air duct and is used to transport the hot air from the roasting section and the homogenizing section to the exhaust drying section and the preheating section.

[0011] Optionally, the belt roaster further includes: A hot air cooling box is connected to the bottom of the hot air cooling section; The cooling duct is connected at one end to the regenerative air duct and at the other end to the hot air cooling box. A cooling fan is connected to the cooling duct and is used to transport part of the hot air in the regenerative duct to the hot air cooling section.

[0012] Optionally, the belt roaster further includes: The combustion assembly is used to deliver the heat generated by combustion to the preheating section, the roasting section, and the hot air duct.

[0013] Optionally, the belt roaster further includes: A forced-air drying oven hood is connected to the top of the forced-air drying section; The discharge pipe is connected to the blower drying oven hood; An exhaust fan is connected to the exhaust pipe and is used to extract the exhaust gas from the blower drying section.

[0014] Optionally, the belt roaster further includes: The combustion-supporting pipe assembly has one end connected to the exhaust pipe and the other end connected to the combustion assembly; A combustion-supporting fan is connected to the combustion-supporting pipe assembly and is used to transport part of the exhaust gas in the discharge pipe to the combustion assembly for combustion support.

[0015] Optionally, the belt roaster further includes: A medium-temperature air duct assembly is connected at one end to the top of the first air-cooling section and at the other end to the top of the preheating section, so that hot air from the first air-cooling section can enter the preheating section through the medium-temperature air duct assembly. The high-temperature air duct assembly is connected at one end to the top of the hot air cooling section, the warm air cooling section and the first air cooling section, and at the other end to the top of the roasting section, so that the hot air from the hot air cooling section, the warm air cooling section and the first air cooling section can be mixed and enter the roasting section.

[0016] As can be seen from the above technical solution, the belt roaster with staged cooling and heat recovery provided by this utility model has the following advantages: This belt roaster can achieve staged cooling and heat recovery, improve resource utilization efficiency, and also improve the problem of air leakage between the roasting section, the soaking section and the cooling section.

[0017] Other features and advantages of this invention will be set forth in the following description. Attached Figure Description

[0018] The accompanying drawings are provided to further understand the technical solution of this utility model and constitute a part of the specification. They are used together with the embodiments of this utility model to explain the technical solution of this utility model, and do not constitute a limitation on the technical solution of this utility model.

[0019] Figure 1 This is a schematic diagram of the overall structure of the belt roaster in this embodiment of the present invention; Figure 2 This is a schematic diagram of the belt roasting machine in the embodiment of this utility model, mainly used to show the sequence of each process section; Figure 3 This is a schematic diagram of the belt roaster in this embodiment of the present invention, mainly used to show the location and connection relationship of the hot air ducts; Figure 4 This is a schematic diagram of the belt roaster in this embodiment of the present invention, mainly used to show the position and connection relationship of components such as the regenerating air duct; Figure 5 This is a schematic diagram of the belt roaster in this embodiment of the present invention, mainly used to show the position and connection relationship of components such as the first recovery pipe; Figure 6 This is a schematic diagram of the belt roasting machine in this embodiment of the present invention, mainly used to show the position and connection relationship of components such as the medium-temperature air duct assembly and the high-temperature air duct assembly.

[0020] Explanation of reference numerals in the attached figures: 1. Drying section; 101. Blow-air drying section; 102. Exhaust-air drying section; 2. Preheating section; 3. Calcination section; 4. Soaking section; 5. Primary cooling section; 501. Hot air cooling section; 502. Warm air cooling section; 6. Secondary cooling section; 601. First air-cooling section; 602. Second air-cooling section; 7. Protective partition wall; 8. Hot air duct; 9. Exhaust-air drying furnace hood; 10. First calcination air box; 11. Soaking air box; 12. Regenerating air duct; 13. Regenerating air fan; 14. Hot air cooling air box; 15. Cooling air duct; 16. Cooling fan; 17. First air-cooling air box; 18. 19. Second air-cooled air box; 20. Air inlet pipe; 21. Air inlet fan; 22. Second air-cooled furnace hood; 23. Blowering drying air box; 24. First recovery pipe; 25. Blowering fan; 26. Warm air cooling air box; 27. Second recovery pipe; 28. Warm air fan; 29. ​​Medium temperature air duct assembly; 30. High temperature air duct assembly; 31. Combustion assembly; 32. Exhaust pipe; 33. Exhaust fan; 34. Combustion-supporting pipe assembly; 35. Combustion-supporting fan; 36. Exhaust drying air box; 37. Preheating air box; 38. Second roasting air box; 39. Exhaust pipe; 40. Exhaust fan. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0022] like Figures 1-6 The illustration shows an embodiment of the present invention, which discloses a belt roaster with staged cooling and heat recovery. The belt roaster includes a drying section 1, a preheating section 2, a roasting section 3, a homogenizing section 4, a primary cooling section 5, and a secondary cooling section 6 arranged sequentially. The drying section 1 includes a forced-air drying section 101 and a forced-air drying section 102. The primary cooling section 5 includes a hot air cooling section 501 and a warm air cooling section 502. The secondary cooling section 6 includes a first air cooling section 601 and a second air cooling section 602. In other words, the belt roaster is sequentially configured as a forced-air drying section 101, a forced-air drying section 102, a preheating section 2, a roasting section 3, a homogenizing section 4, a hot air cooling section 501, a warm air cooling section 502, a first air cooling section 601, and a second air cooling section 602.

[0023] In one embodiment, such as Figure 1 , Figure 2As shown, protective partitions 7 are respectively installed between the blower drying section 101 and the exhaust drying section 102, between the exhaust drying section 102 and the preheating section 2, between the calcination section 3 and the homogenization section 4, between the homogenization section 4 and the hot air cooling section 501, and between the first air cooling section 601 and the second air cooling section 602 to prevent air leakage between the corresponding process sections, especially between the calcination section 3, the homogenization section 4, and the primary cooling section 5, effectively ensuring the temperature of the homogenization section 4.

[0024] In this embodiment, the belt calciner with staged cooling and heat recovery achieves staged cooling of the pellets through a hot air cooling section 501, a warm air cooling section 502, a first air cooling section 601, and a second air cooling section 602, effectively improving the problem of cracking during the rapid cooling of the pellets. Simultaneously, protective partitions 7 are added between the corresponding process sections to effectively improve the problem of air leakage between them.

[0025] In one embodiment, such as Figure 1 , Figure 3 As shown, the belt roaster also includes a hot air duct 8, one end of which is connected to the top of the second air cooling section 602 and the other end is connected to the top of the heat equalization section 4, so that the hot air from the second air cooling section 602 can enter the heat equalization section 4, which can both improve the heat equalization section 4 and achieve effective utilization of heat.

[0026] In one embodiment, such as Figure 1 , Figure 4 As shown, the belt calciner also includes an exhaust drying hood 9, a first calcining air box 10, a homogenizing air box 11, a regenerating air duct 12, and a regenerating fan 13. The exhaust drying hood 9 is connected to the top of the exhaust drying section 102, and the first calcining air box 10 is connected to the bottom of the calcining section 3. The homogenizing air box 11 is connected to the bottom of the homogenizing section 4. One end of the regenerating air duct 12 is connected to the first calcining air box 10 and the homogenizing air box 11 respectively, and the other end is connected to the exhaust drying hood 9 and the preheating section 2 respectively. The regenerating fan 13 is connected to the regenerating air duct 12, and the regenerating fan 13 is used to transport the hot air from the calcining section 3 and the homogenizing section 4 to the exhaust drying section 102 and the preheating section 2 for pellet drying and preheating, thereby realizing the rational recovery and utilization of heat.

[0027] In one embodiment, such as Figure 1 , Figure 4 As shown, the belt roaster also includes a hot air cooling box 14, a cooling duct 15, and a cooling fan 16. The hot air cooling box 14 is connected to the bottom of the hot air cooling section 501. One end of the cooling duct 15 is connected to the reheat air duct 12, and the other end is connected to the hot air cooling box 14. The cooling fan 16 is connected to the cooling duct 15, and the cooling fan 16 is used to transport part of the hot air in the reheat air duct 12 to the hot air cooling section 501 for pellet cooling.

[0028] In one embodiment, such as Figure 1 , Figure 5 As shown, the bottom of the first air-cooled section 601 is connected to a first air-cooled box 17, and the bottom of the second air-cooled section 602 is connected to a second air-cooled box 18. The bottoms of the first air-cooled box 17 and the second air-cooled box 18 are respectively connected to air inlet pipes 19, and each air inlet pipe 19 is connected to an air inlet fan 20, which is used to blow cold air into the first air-cooled section 601 and the second air-cooled section 602.

[0029] In one embodiment, such as Figure 1 , Figure 5 As shown, the top of the second air-cooled section 602 is connected to the second air-cooled furnace hood 21, and the bottom of the blower drying section 101 is connected to the blower drying box 22. The second air-cooled furnace hood 21 and the blower drying box 22 are connected through the first recovery pipe 23. The first recovery pipe 23 is connected to the blower drying fan 24, and the blower drying fan 24 is used to blow the hot air from the second air-cooled section 602 into the blower drying section 101 for pellet drying.

[0030] In one embodiment, such as Figure 1 , Figure 5 As shown, a warm air cooling box 25 is connected to the bottom of the warm air cooling section 502. The warm air cooling box 25 is connected to the first recovery pipe 23 through a second recovery pipe 26. A warm air fan 27 is connected to the second recovery pipe 26. The warm air fan 27 is used to blow part of the hot air in the first recovery pipe 23 into the warm air cooling section 502 for pellet cooling.

[0031] In one embodiment, such as Figure 1 , Figure 6 As shown, the belt roaster also includes a medium-temperature air duct assembly 28. One end of the medium-temperature air duct assembly 28 is connected to the top of the first air cooling section 601, and the other end is connected to the top of the preheating section 2, so that the hot air from the first air cooling section 601 can enter the preheating section 2 through the medium-temperature air duct assembly 28 for pellet preheating.

[0032] In one embodiment, such as Figure 1 , Figure 6 As shown, the belt roaster also includes a high-temperature air duct assembly 29. One end of the high-temperature air duct assembly 29 is connected to the top of the hot air cooling section 501, the warm air cooling section 502 and the first air cooling section 601, and the other end is connected to the top of the roasting section 3, so that the hot air from the hot air cooling section 501, the warm air cooling section 502 and the first air cooling section 601 can be mixed and enter the roasting section 3, thereby increasing the furnace temperature of the roasting section 3.

[0033] In one embodiment, such as Figure 1 , Figure 6As shown, the belt roaster also includes a combustion assembly 30, which is used to transport the heat generated by combustion to the preheating section 2, the roasting section 3 and the hot air duct 8 to achieve supplemental heating of the preheating section 2, the roasting section 3 and the hot air duct 8.

[0034] In this embodiment, the exhaust pipe of the combustion assembly 30 is connected to the medium-temperature air duct group 28, the high-temperature air duct group 29 and the hot air duct 8 respectively, so that the heat generated by the combustion of the combustion assembly 30 can be quickly transported to the medium-temperature air duct group 28, the high-temperature air duct group 29 and the hot air duct 8.

[0035] Since the high-temperature air duct assembly 29 is connected to the roasting section 3, it can effectively increase the furnace temperature and reduce fuel consumption, while also allowing the use of low-calorific-value fuels. The medium-temperature air duct assembly 28 is connected to the preheating section 2. Since there is no protective partition wall 7 between the preheating section 2 and the roasting section 3, the temperature field inside the furnace no longer changes gradually, but naturally forms a temperature gradient.

[0036] The function of the heat equalization section 4 is to ensure that the temperature of the upper and lower material layers is uniform and to reduce the ferrous oxide content. The low-temperature air duct group is connected to the heat equalization section 4, and the temperature is raised to above 1100℃ through a small amount of external supplementary heating. The oxygen content of the mixed hot air is still above 18%, thus meeting the process requirements.

[0037] In one embodiment, such as Figure 1 , Figure 6 As shown, the belt roaster also includes a forced-air drying furnace hood 31, an exhaust pipe 32, and an exhaust fan 33. The forced-air drying furnace hood 31 is connected to the top of the forced-air drying section 101, the exhaust pipe 32 is connected to the forced-air drying furnace hood 31, and the exhaust fan 33 is connected to the exhaust pipe 32. The exhaust fan 33 is used to extract the exhaust gas from the forced-air drying section 101.

[0038] In one embodiment, such as Figure 1 , Figure 6 As shown, the belt roaster also includes a combustion-supporting pipe assembly 34 and a combustion-supporting fan 35. One end of the combustion-supporting pipe assembly 34 is connected to the discharge pipe 32, and the other end is connected to the combustion assembly 30. The combustion-supporting fan 35 is connected to the combustion-supporting pipe assembly 34, and the combustion-supporting fan 35 is used to transport part of the exhaust gas in the discharge pipe 32 to the combustion assembly 30 for combustion support, thereby realizing the recycling of exhaust gas.

[0039] In this embodiment, a portion of the exhaust gas from the blower drying section 101 is used as primary combustion air to control the combustion flame. The primary combustion air volume accounts for 10% of the total air consumption for combustion. Meanwhile, the combustion air blower 35 is a heat-resistant blower that can withstand hot air at 150°C.

[0040] In one embodiment, such as Figure 1 , Figure 6As shown, the belt roaster also includes an exhaust drying air box 36, a preheating air box 37, a second roasting air box 38, an exhaust pipe 39, and an exhaust fan 40. The exhaust drying air box 36 is connected to the bottom of the exhaust drying section 102, the preheating air box 37 is connected to the bottom of the preheating section 2, and the second roasting air box 38 is connected to the bottom of the roasting section 3. One end of the exhaust pipe 39 is connected to the exhaust drying air box 36, the preheating air box 37, and the second roasting air box 38 respectively, and the other end is used to connect to external waste gas treatment equipment. The exhaust fan 40 is connected to the exhaust pipe 39.

[0041] In this belt calciner, the pellets sequentially pass through a forced-air drying section 101, an exhaust drying section 102, a preheating section 2, a calcination section 3, a homogenization section 4, a hot air cooling section 501, a warm air cooling section 502, a first air cooling section 601, and a second air cooling section 602. During this process, a forced-air blower 24 delivers hot air from the second air cooling section 602 into the forced-air drying section 101 to dry the green pellet layer. Part of the dried flue gas is discharged to an external waste gas treatment device through an exhaust pipe 32, while the other part is used to aid combustion in the combustion assembly 30. Simultaneously, a warm air blower 27 delivers a portion of the hot air from the first recovery pipe 23 to the warm air cooling section 502 for pellet cooling.

[0042] Simultaneously, the regenerating air fan 13 sends a portion of the hot air from the roasting section 3 and the homogenizing section 4 into the exhaust drying section 102 to fully dry the green pellet layer, while another portion is sent into the preheating section 2 to fully preheat the green pellet layer, thus achieving rational utilization of heat. The cooling fan 16 transports a portion of the hot air from the regenerating air duct 12 to the hot air cooling section 501 for use in cooling the pellets.

[0043] In addition, the hot air from the first air-cooling section 601 enters the preheating section 2 through the medium-temperature air duct assembly 28, and fully preheats the green pellet bed. The hot air from the homogenization section 4, the hot air cooling section 501, the warm air cooling section 502, and the first air-cooling section 601 enters the calcination section 3 through the high-temperature air duct assembly 29 to increase the furnace temperature. The heat generated by the combustion in the combustion assembly 30 enters the medium-temperature air duct assembly 28, the low-temperature air duct assembly, and the hot air duct 8 to achieve supplemental heating.

[0044] As described above, this belt calciner can perform staged cooling of high-temperature pellets, gradually reducing the temperature from high to medium and then to air cooling, effectively preventing cracks from occurring during the rapid cooling process. Simultaneously, this belt calciner enables waste gas recycling, reducing emissions, improving the thermal efficiency of the belt calciner, lowering process energy consumption, and achieving energy conservation and emission reduction, making it worthy of application and promotion.

[0045] It should be noted that, unless otherwise stated, the technical or scientific terms used in this utility model shall have the ordinary meaning as understood by those skilled in the art to which this utility model pertains.

[0046] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly defined.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This utility model is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A belt roaster with staged cooling and heat recovery, characterized in that, The system includes, in sequence, a drying section (1), a preheating section (2), a calcining section (3), a homogenizing section (4), a primary cooling section (5), and a secondary cooling section (6), and also includes: A protective partition wall (7) is provided at least between the calcination section (3) and the homogenization section (4), and between the homogenization section (4) and the primary cooling section (5); A hot air duct (8) is connected at one end to the top of the secondary cooling section (6) and at the other end to the top of the heat exchange section (4) so ​​that the hot air from the secondary cooling section (6) can enter the heat exchange section (4).

2. The belt roaster with staged cooling and heat recovery according to claim 1, characterized in that, The drying section (1) includes a blower drying section (101) and an exhaust drying section (102), and protective partitions (7) are respectively provided between the blower drying section (101) and the exhaust drying section (102), and between the exhaust drying section (102) and the preheating section (2).

3. The belt roaster with staged cooling and heat recovery according to claim 2, characterized in that, The primary cooling section (5) includes a hot air cooling section (501) and a warm air cooling section (502), and the protective partition (7) is disposed between the heat equalization section (4) and the hot air cooling section (501).

4. The belt roaster with staged cooling and heat recovery according to claim 3, characterized in that, The secondary cooling section (6) includes a first air-cooled section (601) and a second air-cooled section (602), and the protective partition wall (7) is also provided between the first air-cooled section (601) and the second air-cooled section (602).

5. The belt roaster with staged cooling and heat recovery according to claim 3, characterized in that, The belt roaster also includes: A ventilation drying oven hood (9) is connected to the top of the ventilation drying section (102); The first roasting air box (10) is connected to the bottom of the roasting section (3); A heat exchanger box (11) is connected to the bottom of the heat exchanger section (4); The regenerating air duct (12) is connected at one end to the first roasting air box (10) and the homogenizing air box (11) respectively, and at the other end to the exhaust drying furnace hood (9) and the preheating section (2) respectively. A regenerating air blower (13) is connected to the regenerating air duct (12) and is used to transport the hot air from the roasting section (3) and the homogenizing section (4) to the exhaust drying section (102) and the preheating section (2).

6. The belt roaster with staged cooling and heat recovery according to claim 5, characterized in that, The belt roaster also includes: A hot air cooling box (14) is connected to the bottom of the hot air cooling section (501); The cooling air duct (15) is connected at one end to the heat return air duct (12) and at the other end to the hot air cooling box (14); A cooling fan (16) is connected to the cooling air duct (15) and is used to transport part of the hot air in the regenerative air duct (12) to the hot air cooling section (501).

7. The belt roaster with staged cooling and heat recovery according to claim 2, characterized in that, The belt roaster also includes: Combustion assembly (30) is used to deliver the heat generated by combustion to the preheating section (2), the roasting section (3) and the hot air duct (8).

8. The belt roaster with staged cooling and heat recovery according to claim 7, characterized in that, The belt roaster also includes: A forced-air drying oven hood (31) is connected to the top of the forced-air drying section (101); The discharge pipe (32) is connected to the blower drying oven hood (31); An exhaust fan (33) is connected to the exhaust pipe (32) and is used to exhaust the exhaust gas from the blower drying section (101).

9. The belt roaster with staged cooling and heat recovery according to claim 8, characterized in that, The belt roaster also includes: The combustion-supporting pipe assembly (34) is connected at one end to the discharge pipe (32) and at the other end to the combustion assembly (30); A combustion-supporting blower (35) is connected to the combustion-supporting pipe assembly (34) and is used to transport part of the exhaust gas in the discharge pipe (32) to the combustion assembly (30) for combustion support.

10. The belt roaster with staged cooling and heat recovery according to claim 4, characterized in that, The belt roaster also includes: The medium-temperature air duct assembly (28) is connected at one end to the top of the first air-cooling section (601) and at the other end to the top of the preheating section (2) so that the hot air from the first air-cooling section (601) can enter the preheating section (2) through the medium-temperature air duct assembly (28). The high-temperature air duct assembly (29) is connected at one end to the top of the hot air cooling section (501), the warm air cooling section (502) and the first air cooling section (601), and at the other end to the top of the roasting section (3), so that the hot air from the hot air cooling section (501), the warm air cooling section (502) and the first air cooling section (601) can be mixed and enter the roasting section (3).

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