A hot blast stove waste heat utilization system

Abstract

The utility model discloses a kind of hot blast stove waste heat utilization systems, belong to ceramic production equipment field, including drying chamber, hot blast stove, hot blast stove air inlet pipeline, hot blast stove air outlet pipeline, circulating fan, exhaust flue and exhaust heat exchanger, the import of hot blast stove is connected with hot blast stove air inlet pipeline, export is connected with the import of circulating fan, the export of circulating fan is connected with drying chamber by hot blast stove air outlet pipeline, exhaust heat exchanger is installed in exhaust flue middle part in series, and exhaust heat exchanger is connected on hot blast stove air inlet pipeline by auxiliary pipeline parallel connection. High-temperature flue gas waste heat is recovered by exhaust heat exchanger, for preheating the air entering hot blast stove, greatly reduce exhaust flue heat loss and gas consumption, improve the overall thermal efficiency of system, economic benefit is remarkable. Utilize the circulating fan of original system as power source, through bypass pipeline design, without adding new induced draft fan, equipment investment and operating power consumption are saved.

Description

Technical Field

[0001] This utility model belongs to the field of ceramic production equipment, and in particular relates to a waste heat utilization system for hot blast stoves suitable for ceramic production. Background Technology

[0002] The ceramics industry is a typical high-energy-consuming industry, with heat energy costs accounting for a significant proportion of production and operation. Especially in the production of sanitary ceramics, the drying process of the ceramic body requires a large amount of heat energy. Currently, hot air furnaces are commonly used to provide the heat source, and the heated air is sent into the drying chamber by a circulating fan to achieve uniform drying of the ceramic body. The industry widely uses indirect-wall hot air furnaces, whose working principle is as follows: Gas combustion in the furnace generates high-temperature flue gas, which indirectly exchanges heat with the low-temperature air drawn back from the drying chamber by the circulating fan in a heat exchanger, thus heating the air. The cooled flue gas is then directly discharged into the atmosphere through an exhaust duct.

[0003] However, traditional indirect-flow hot blast furnaces have several limitations in terms of structure and process. First, due to limitations in equipment size and installation space, heat exchangers often cannot be configured with sufficient heat exchange area, resulting in low heat exchange efficiency. Second, to prevent low-temperature corrosion of the heat exchanger by acidic condensates in the flue gas, the exhaust gas temperature usually needs to be maintained at a high level (typically 200℃ to 300℃ or even higher), resulting in a significant loss of high-quality heat energy. In addition, due to uneven distribution of flue gas and air flow and unreasonable arrangement of heat exchange tube bundles, flow dead zones and heat exchange blind zones are easily formed, further reducing the actual heat exchange efficiency and causing serious energy waste.

[0004] Currently, most ceramic factories' hot blast stove systems lack effective waste heat recovery devices, resulting in the direct emission of high-temperature flue gas. This not only wastes energy but also increases fuel costs and environmental burden. Therefore, there is an urgent need for a waste heat utilization system with a reasonable structure, simple modification, and high heat recovery efficiency. This system should be able to be retrofitted at low cost to existing hot blast stove systems, achieving efficient recovery and utilization of flue gas waste heat, improving overall thermal efficiency, and reducing production costs. Utility Model Content

[0005] To overcome the shortcomings of existing technologies, a waste heat utilization system for hot blast stoves is provided. This system can efficiently recover waste heat from the high-temperature flue gas emitted from the hot blast stove to preheat the air entering the stove, thereby significantly reducing flue gas heat loss and fuel consumption. Furthermore, the system has low modification costs, stable operation, and convenient maintenance. Details are as follows:

[0006] A waste heat utilization system for a hot blast stove includes a drying chamber, a hot blast stove, a hot blast stove inlet duct, a hot blast stove outlet duct, a circulating fan, a flue gas heat exchanger, and a flue gas duct. The inlet of the hot blast stove is connected to the hot blast stove inlet duct, and the outlet is connected to the inlet of the circulating fan. The outlet of the circulating fan is connected to the drying chamber through the hot blast stove outlet duct. The flue gas heat exchanger is installed in series in the middle of the flue gas duct, and the flue gas heat exchanger is connected in parallel to the hot blast stove inlet duct through an auxiliary pipe.

[0007] The above technical solution connects the flue gas heat exchanger in series with the flue gas duct and connects it in parallel with the main air intake duct via an auxiliary pipe. Utilizing the existing circulating fan power, the waste heat from the high-temperature flue gas that would otherwise be discharged is used to preheat the air entering the hot blast stove. This achieves cascaded energy utilization without adding an extra induced draft fan, significantly reduces flue gas heat loss, improves the overall thermal efficiency of the system, saves fuel consumption, and has significant economic benefits.

[0008] Furthermore, the flue gas heat exchanger includes a shell, a flue gas inlet / outlet hood, a circulating gas inlet / outlet hood, and a plurality of finned tubes. The flue gas inlet / outlet hood is disposed at opposite ends of the shell and connected to the flue gas duct. The plurality of finned tubes are equidistantly disposed inside the shell, and the ends of the finned tubes are connected to the flue gas inlet / outlet hood. The circulating gas inlet / outlet hood is disposed at the two ends of the shell adjacent to the flue gas inlet / outlet hood and connected to the auxiliary duct. A dust removal port cover is provided on the upper end face of the shell, and a drain port is provided at the bottom of the shell.

[0009] Furthermore, a first guide plate is provided on the inner side of the flue gas inlet / outlet hood to evenly distribute the flue gas to the entire finned tube area, and the first guide plate is fixedly connected to the inner wall of the flue gas inlet / outlet hood.

[0010] Furthermore, a second guide plate is provided on the inner side of the circulating air inlet / outlet hood to evenly distribute the circulating air into the finned tube, and the second guide plate is fixedly connected to the inner wall of the circulating air inlet / outlet hood.

[0011] Furthermore, both of the auxiliary pipes are equipped with a gate valve at the end near the flue gas heat exchanger.

[0012] Furthermore, the pipes and equipment casings of the system are all equipped with insulation layers.

[0013] Furthermore, the flue gas inlet / outlet hood and the recirculated gas inlet / outlet hood are detachably installed with the housing.

[0014] Furthermore, the auxiliary pipe is a newly installed parallel bypass pipe on the original hot blast stove air inlet pipe.

[0015] Furthermore, the base tube of the finned tube is made of stainless steel, and the fins are made of aluminum.

[0016] The beneficial effects of adopting the technical solution of this utility model are as follows:

[0017] (1) This utility model, through the high-efficiency finned tube heat exchanger connected in series with the flue gas duct and the bypass design connected in parallel with the circulating air inlet duct, successfully captures the waste heat in the high-temperature flue gas that was originally directly discharged into the atmosphere and uses it to preheat the circulating air entering the hot air furnace. This directly reduces the fuel consumption required for the hot air furnace to heat the air to the target temperature, greatly improves the overall thermal efficiency of the entire drying system, reuses the high-temperature flue gas discharged from the hot air furnace, and does not add new electrical equipment, resulting in significant economic benefits.

[0018] (2) The existing circulating fan in the original system is used as the power source, and part of the airflow is guided through the heat exchanger through the bypass pipe, without the need to add an additional induced draft fan. This design greatly simplifies the system structure and is particularly suitable for the technical transformation of existing hot blast furnace systems, saving additional equipment investment and long-term operating power consumption, and reducing the implementation threshold and total life cycle cost.

[0019] (3) The detachable inlet / outlet hood, ash removal port, and drain port make cleaning and maintenance simple and easy, effectively preventing heat exchange efficiency degradation due to ash accumulation and ensuring the durability of system performance. The selection of stainless steel base tubes and aluminum fins ensures both the durability against flue gas corrosion and maximizes heat exchange efficiency by utilizing the high thermal conductivity of aluminum, solving the problem of balancing efficiency and durability. The guide plates set on both sides of the flue gas and air ensure that the fluid (flue gas and air) can be evenly distributed in the heat exchange chamber, fully contacting all heat exchange surfaces, eliminating flow dead zones and short circuits, maximizing the utilization of the heat exchange area, and thus significantly improving the heat transfer efficiency of the entire heat exchanger. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an overall layout diagram of a waste heat utilization system for a hot blast stove according to this utility model;

[0022] Figure 2 This is a schematic diagram of the exhaust heat exchanger structure of a waste heat utilization system for a hot blast stove;

[0023] Figure 3 This is a top view of the flue gas heat exchanger of a waste heat utilization system for a hot blast stove according to a utility model.

[0024] Figure 4 yes Figure 3 A cross-sectional view of the intermediate exhaust gas heat exchanger (AA section).

[0025] Figure 5 yes Figure 3 BB cross-sectional view of the intermediate exhaust gas heat exchanger;

[0026] In the diagram, 1. Drying chamber; 2. Hot air furnace; 3. Hot air furnace inlet duct; 4. Hot air furnace outlet duct; 5. Circulating fan; 6. Exhaust heat exchanger; 7. Exhaust duct; 8. Auxiliary duct; 701. Shell; 702. Flue gas inlet / outlet hood; 703. Circulating gas inlet / outlet hood; 704. Finned tube; 705. Ash removal port cover; 706. Sewage outlet; 9. First guide plate; 10. Second guide plate; 11. Slide valve. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0028] This embodiment successfully captures the waste heat from the high-temperature flue gas that would otherwise be directly discharged into the atmosphere by using a high-efficiency finned tube heat exchanger connected in series with the exhaust duct and a bypass design connected in parallel with the air inlet duct. This waste heat is then used to preheat the circulating air entering the hot blast stove. This reduces the fuel consumption required for the hot blast stove to heat the air to the target temperature. The specific implementation method is as follows:

[0029] Reference Figures 1-5 As shown, a waste heat utilization system for a hot blast stove 2 includes a drying chamber 1, a hot blast stove 2, a hot blast stove inlet duct 3, a hot blast stove outlet duct 4, a circulating fan 5, a flue gas heat exchanger 6, and a flue gas duct 7. The inlet of the hot blast stove 2 is connected to the hot blast stove inlet duct 3, and the outlet is connected to the inlet of the circulating fan 5. The outlet of the circulating fan 5 is connected to the drying chamber 1 through the hot blast stove outlet duct 4. The flue gas heat exchanger 6 is installed in series in the middle of the flue gas duct 7, and the flue gas heat exchanger 6 is connected in parallel to the hot blast stove inlet duct 3 through an auxiliary pipe 8.

[0030] Here, the exhaust heat exchanger 6 is connected in series with the exhaust duct 7 of the hot blast stove, and connected in parallel with the air inlet duct 3 of the hot blast stove via an auxiliary duct 8, thus realizing the recovery of waste heat from the high-temperature flue gas. Without the need to add a new induced draft fan, the waste heat in the flue gas can be used to preheat the air entering the hot blast stove 2, thereby reducing fuel consumption, improving thermal efficiency, saving construction and operating costs, and reducing energy waste.

[0031] In a preferred embodiment, the flue gas heat exchanger 6 includes a shell 701, a flue gas inlet / outlet hood 702, a circulating gas inlet / outlet hood 703, and finned tubes 704. The flue gas inlet / outlet hood 702 is disposed at opposite ends of the shell 701 and connected to the flue gas duct 7. The finned tubes 704 are disposed inside the shell 701, and the two ends of the finned tubes 704 are connected to the flue gas inlet / outlet hood 702. The circulating gas inlet / outlet hood 703 is disposed on the shell 701 at the two ends adjacent to the flue gas inlet / outlet hood 702 and connected to the auxiliary duct 8. A dust removal port cover 705 is provided on the upper surface of the shell 701, and a drain port 706 is provided at the bottom of the shell 701.

[0032] Here, a highly efficient and reliable heat exchange unit is constructed through the modular design of the shell 701, interfaces, and internal finned tubes 704. The inclusion of a dust removal port and a drain port 706 solves the critical problem of ash accumulation in waste heat recovery, facilitating regular maintenance and cleaning, maintaining high-efficiency heat exchange performance over a long period, preventing system efficiency degradation or malfunctions due to ash blockage, and ensuring continuous and stable system operation.

[0033] In a preferred embodiment, a first guide plate 9 is provided on the inner side of the flue gas inlet / outlet hood 702 to distribute the flue gas evenly to the entire finned tube 704 area. The first guide plate 9 is fixedly connected to the inner wall of the flue gas inlet / outlet hood 702.

[0034] Here, the fluid distribution on the flue gas side is optimized by adding a first guide plate 9. It enables the high-temperature flue gas to flow evenly across the entire cross-section of the finned tube bundle 704, avoiding flow dead zones or short circuits in the flue gas within the heat exchanger, ensuring that all heat exchange areas are effectively utilized, preventing local overheating or uneven heat exchange, thereby improving the heat transfer efficiency of the heat exchanger.

[0035] In a preferred embodiment, a second guide plate 10 is provided on the inner side of the circulating air inlet / outlet hood 703 to distribute the circulating air evenly into the finned tube 704. The second guide plate 10 is fixedly connected to the inner wall of the circulating air inlet / outlet hood 703.

[0036] Here, the fluid distribution on the air side is optimized by adding a second guide plate 10. It allows the circulating air from the auxiliary pipe 8 to enter and flow evenly through the interior of each finned tube 704, ensuring sufficient contact and heat exchange between the air and the pipe wall. It also avoids the problem of uneven flow, further taps the heat exchange potential, and improves the efficiency of the entire waste heat recovery process.

[0037] In a preferred embodiment, both auxiliary pipes 8 are equipped with gate valves 11 at the ends near the flue gas heat exchanger 6.

[0038] Here, the installation of gate valve 11 improves the maintainability and operational flexibility of the system. When it is necessary to inspect or isolate the flue gas heat exchanger 6, closing gate valve 11 can cut off the airflow without stopping the entire hot blast stove 2 system, thus enabling online maintenance and ensuring the continuity and stability of the main production.

[0039] As a preferred embodiment, the system's pipes and equipment casings are all equipped with insulation layers.

[0040] Here, by adding insulation layers to pipes and equipment, heat loss during waste heat recovery and transmission is minimized. On the one hand, the recovered heat is used more concentratedly in the process, further improving energy efficiency; on the other hand, the surface temperature of the equipment is reduced, effectively preventing the risk of burns to operators and improving the safety of the working environment.

[0041] In a preferred embodiment, the flue gas inlet / outlet hood 702 and the recirculated gas inlet / outlet hood 703 are detachably installed from the housing 701.

[0042] Here, by making the inlet and outlet shrouds detachable, the core components of the heat exchanger (finned tube 704) are more easily accessible, which greatly facilitates maintenance work such as cleaning and inspection, ensuring the thoroughness and convenience of maintenance work, so as to guarantee the long-term efficient operation of the heat exchanger.

[0043] As a preferred embodiment, the auxiliary pipe 8 is a newly installed parallel bypass pipe on the original hot blast stove air inlet pipe 3.

[0044] Here, the specific implementation method of auxiliary pipe 8 is clarified, emphasizing the system's ease of modification and low-cost advantages. No changes to the main air duct structure are required; system integration can be achieved simply by adding a parallel bypass pipe. This simplifies the installation process, reduces the complexity and investment cost of the modification project, and is particularly suitable for energy-saving technological upgrades to existing hot blast stove 2 systems.

[0045] In a preferred embodiment, the base tube of the finned tube 704 is made of stainless steel, and the fins are made of aluminum.

[0046] Here, the material of the 704 finned tube was optimized and limited. Considering the corrosive nature of the flue gas and the requirement for highly efficient heat exchange, the optimal material combination was selected. The stainless steel base tube ensures structural strength and resistance to flue gas corrosion, extending the equipment's service life; the aluminum fins utilize their excellent thermal conductivity and expandable surface area, significantly increasing the effective heat exchange area while controlling costs, thus achieving the best overall performance in terms of high efficiency, durability, and economy.

[0047] During system operation, the circulating fan 5 simultaneously provides two airflows. A primary airflow enters the hot blast furnace 2 through the hot blast furnace inlet duct 3, is heated, and then flows into the drying chamber 1. The other branch airflow, drawn by the circulating fan 5, is diverted from the hot blast furnace inlet duct 3 and enters the exhaust heat exchanger 6 via the auxiliary duct 8. Simultaneously, the high-temperature flue gas (approximately 200°C or higher) generated by the hot blast furnace 2 flows into the finned tubes 704 of the exhaust heat exchanger 6 through the exhaust duct 7. Inside the heat exchanger, the high-temperature flue gas undergoes efficient heat exchange with the low-temperature branch air flowing outside the finned tubes. The flue gas is cooled and discharged from the exhaust duct 7, while the branch air is preheated and re-enters the hot blast furnace inlet duct 3. This preheated air then re-enters the hot blast furnace 2, thereby reducing the fuel consumption required for the hot blast furnace to heat the target temperature and achieving waste heat recovery.

[0048] When maintenance is required, simply close both gate valves 11 to disconnect the flue gas heat exchanger 6 from the system for online inspection. During regular maintenance, the cleaning port cover 705 can be opened to clean the outer wall of the finned tubes 704, or the flue gas inlet / outlet hood 702 can be removed for a more thorough cleaning, thus ensuring the long-term efficient operation of the heat exchanger.

[0049] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the substance and scope of the present invention. Various modifications made by those skilled in the art to the above embodiments after reading this specification are all within the scope of protection of the present invention.

Claims

1. A waste heat utilization system for a hot blast stove, characterized in that, The equipment includes a drying chamber (1), a hot air furnace (2), a hot air furnace inlet pipe (3), a hot air furnace outlet pipe (4), a circulating fan (5), a flue gas heat exchanger (6), and a flue gas pipe (7). The inlet of the hot air furnace (2) is connected to the hot air furnace inlet pipe (3), and the outlet is connected to the inlet of the circulating fan (5). The outlet of the circulating fan (5) is connected to the drying chamber (1) through the hot air furnace outlet pipe (4). The flue gas heat exchanger (6) is installed in series in the middle of the flue gas pipe (7), and the flue gas heat exchanger (6) is connected in parallel to the hot air furnace inlet pipe (3) through an auxiliary pipe (8).

2. The waste heat utilization system of a hot blast stove (2) according to claim 1, characterized in that, The flue gas heat exchanger (6) includes a shell (701), a flue gas inlet / outlet hood (702), a circulating gas inlet / outlet hood (703), and a plurality of finned tubes (704). The flue gas inlet / outlet hood (702) is located at opposite ends of the shell (701) and is connected to the flue gas pipe (7). The plurality of finned tubes (704) are equidistantly located inside the shell (701), and the two ends of the finned tubes (704) are connected to the flue gas inlet / outlet hood (702). The circulating gas inlet / outlet hood (703) is located at the two ends of the shell (701) adjacent to the flue gas inlet / outlet hood (702) and is connected to the auxiliary pipe (8). A dust removal port cover (705) is provided on the upper surface of the shell (701), and a drain port (706) is provided on the bottom of the shell (701).

3. The waste heat utilization system for a hot blast stove according to claim 2, characterized in that, The flue gas inlet / outlet hood (702) is provided with a first guide plate (9) on its inner side, which is used to evenly distribute the flue gas to the entire finned tube (704) area. The first guide plate (9) is fixedly connected to the inner wall of the flue gas inlet / outlet hood (702).

4. A waste heat utilization system for a hot blast stove according to claim 2, characterized in that, The inner side of the circulating air inlet / outlet hood (703) is provided with a second guide plate (10) for distributing circulating air evenly to the interior of the finned tube (704). The second guide plate (10) is fixedly connected to the inner wall of the circulating air inlet / outlet hood (703).

5. A waste heat utilization system for a hot blast stove according to claim 1, characterized in that, Both auxiliary pipes (8) are equipped with a gate valve (11) at the end near the flue gas heat exchanger (6).

6. A waste heat utilization system for a hot blast stove according to claim 1, characterized in that, The pipes and equipment casings of the system are all equipped with insulation layers.

7. A waste heat utilization system for a hot blast stove according to claim 1, characterized in that, The auxiliary pipe (8) is a new parallel bypass pipe installed on the original hot blast stove air inlet pipe (3).

8. A waste heat utilization system for a hot blast stove according to claim 2, characterized in that, The flue gas inlet / outlet hood (702) and the circulating gas inlet / outlet hood (703) are detachably installed with the housing (701).

9. A waste heat utilization system for a hot blast stove according to claim 2, characterized in that, The base tube of the finned tube (704) is made of stainless steel, and the fins are made of aluminum.

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