Smoke recycling type tunnel kiln

Abstract

The utility model discloses a flue gas recycling type tunnel kiln. The flue gas recycling type tunnel kiln comprises a replacement chamber, a preheating chamber, a firing chamber and a cooling chamber which are sequentially arranged, the replacement chamber is provided with a heat exchange water pipe; the preheating chamber is provided with a waste heat gas inlet and a waste heat gas outlet; the firing chamber is provided with a nitrogen transmission port and a smoke exhaust port; the smoke outlet is communicated with the residual hot air inlet through a smoke exhaust pipe; the cooling chamber is provided with a first nitrogen inlet and a cooling water pipe; the water inlet of the heat exchange water pipe is communicated with the water outlet of the cooling water pipe, and the water outlet is communicated with the water inlet of the cooling water pipe. Heat generated after firing and cooling water heat exchange in the firing chamber is recycled, energy waste is avoided, meanwhile, nitrogen needed by the firing chamber is introduced from the tail of the hearth and can be preheated, the problem that in the prior art, the environment temperature of the firing chamber is affected due to the fact that nitrogen is directly introduced into the firing chamber is solved, and the service life of the firing chamber is prolonged. In addition, oil-containing flue gas can be discharged easily, and the firing effect is effectively guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of tunnel kiln technology, and in particular to a flue gas reuse tunnel kiln. Background Technology

[0002] As one of the world's largest countries in terms of installed new energy capacity, my country is vigorously developing the new energy industry and has also issued a series of development and promotion policies to address carbon emissions and environmental pollution. Graphite, as an important anode material for new energy, is currently facing the development trend of major processing enterprises due to the need for optimization of its processing technology and cost reduction. Considering that graphite materials are mainly artificial graphite, and the raw materials for artificial graphite are various petroleum coke or coal-based materials, hydrocarbon gases are inevitably produced during the processing. At the same time, these volatile substances are also a type of impurity that needs to be removed. Therefore, graphite anode material manufacturers usually use tunnel kilns for low-temperature calcination to reduce the volatile substances in the material during processing.

[0003] Existing tunnel kilns typically utilize inert gases as protective gases during heating and calcination to prevent oxidation and surface defects in materials. However, continuous gas exchange easily leads to waste of inert gases, reducing the practicality of the equipment. The applicant previously disclosed a tunnel kiln with a gas recovery and reuse device, comprising: a tunnel kiln body with an internal recycling structure and an external energy-saving structure; however, some shortcomings were discovered during commissioning, such as difficulty in reusing cooling water after heat exchange, and the lack of heat exchange utilization within the tunnel kiln itself; unstable airflow due to nitrogen introduction, and poor preheating effect from the treated flue gas; furthermore, the lack of a replacement gas structure. Therefore, equipment modification based on the existing tunnel kiln is necessary. Summary of the Invention

[0004] The purpose of this utility model is to provide a flue gas reuse tunnel kiln with a simple structure and strong practicality. By recovering and utilizing the heat generated after firing in the firing chamber and heat exchange with cooling water, energy waste is avoided. At the same time, the nitrogen required for the firing chamber is introduced from the tail of the furnace, which can preheat the nitrogen. This solves the problem of nitrogen being directly introduced into the firing chamber and affecting the ambient temperature of the firing chamber in the prior art, and also facilitates the discharge of oily flue gas, effectively ensuring the firing effect.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A flue gas reuse tunnel kiln includes a displacement chamber, a preheating chamber, a firing chamber, and a cooling chamber arranged sequentially. The displacement chamber is equipped with a hot water exchange pipe. The preheating chamber is equipped with a waste heat gas inlet and a waste heat gas outlet. The firing chamber is equipped with a nitrogen transmission port and a flue gas outlet. The flue gas outlet is connected to the waste heat gas inlet through a flue gas pipe. The cooling chamber is equipped with a first nitrogen inlet and a cooling water pipe. The inlet of the hot water exchange pipe is connected to the outlet of the cooling water pipe, and the outlet is connected to the inlet of the cooling water pipe.

[0007] In this invention, the material to be fired passes sequentially through a displacement chamber, a preheating chamber, a firing chamber, and a cooling chamber. The displacement chamber is used to displace the furnace atmosphere to remove air carried in the furnace and the material, preventing oxidation and surface defects. The preheating chamber is used to preheat the material, gradually increasing its temperature to avoid deformation or cracking caused by direct high-temperature firing. The firing chamber is used to fire the product. High-temperature flue gas (containing oil and powder) generated during firing enters the preheating chamber through the exhaust pipe, utilizing the residual heat of the high-temperature flue gas to preheat the material. The cooling chamber is used to cool the product, allowing it to cool down slowly to prevent thermal stress cracking. During the cooling process, cooling water exchanges heat with the product. The cooled water (i.e., hot water) after heat exchange is passed into the hot water exchange pipe, using its heat to preheat the material in the displacement chamber, and then exchange heat again. The water after preheating the material (i.e., cold water) is passed back into the cooling water pipe, achieving water recycling and saving resources.

[0008] In this invention, nitrogen gas is introduced into the cooling chamber through a first nitrogen inlet, and then into the firing chamber. While cooling the fired product, the cooling chamber exchanges heat with the nitrogen gas, preheating the nitrogen before it enters the firing chamber. This prevents the nitrogen from directly entering the firing chamber and affecting the ambient temperature, effectively ensuring the firing effect. Since the high-temperature flue gas is mainly located in the firing chamber, this invention introduces nitrogen gas from the tail end of the furnace, i.e., the cooling chamber. This allows the nitrogen gas flow formed in the furnace to move from the product outlet direction to the product inlet direction, facilitating the discharge of high-temperature flue gas.

[0009] Preferably, isolation gates are provided between the displacement chamber and the preheating chamber, the preheating chamber and the firing chamber, and the firing chamber and the cooling chamber. These isolation gates are commercially available products used to isolate airflow and temperature zones to maintain a stable atmosphere in each area. They are conventionally selected according to needs; in practical applications, they can be lifting gates, flap gates, or other conventional gates. The specific installation and usage methods are conventional techniques and do not affect the understanding of this utility model by those skilled in the art.

[0010] Preferably, the nitrogen transmission port is located on the inner wall at the junction of the cooling chamber and the firing chamber. As is common knowledge, the inner wall refers to the inner wall of a flue gas reuse tunnel kiln. When an isolation gate is provided between the firing chamber and the cooling chamber, the nitrogen in the cooling chamber enters the firing chamber through the nitrogen transmission port to facilitate the installation of the isolation gate without affecting its normal opening and closing.

[0011] Furthermore, the replacement chamber is equipped with a second nitrogen inlet and an air outlet. Some raw materials, such as graphite anode materials, have low requirements for the oxygen content of the entire furnace. After the raw materials enter the replacement chamber, the inlet gate and outlet gate are conventionally sealed. Nitrogen gas is introduced into the replacement chamber while air is exhausted, so that the oxygen mass fraction in the furnace meets the production process requirements for preparing the product.

[0012] Furthermore, the number of exhaust vents is one or more. More preferably, the number of exhaust vents is multiple. The high-temperature flue gas generated during the firing process enters the preheating chamber through the exhaust vents to preheat the material to be fired. As is common sense, the waste gas discharged from the waste heat gas outlet is conventionally treated, such as through air purification, at which point the temperature is relatively low and the oil and powder content is small.

[0013] Preferably, the exhaust pipe is equipped with an inorganic fiber filter cloth. More preferably, the exhaust pipe includes a vertical pipe and a horizontal pipe; the exhaust port, vertical pipe, horizontal pipe, and waste heat gas inlet are sequentially connected and conventionally detachable; the horizontal pipe is equipped with an inorganic fiber filter cloth, while the vertical pipe is not. The inorganic fiber filter cloth can adsorb and filter tar, dust, and other substances in the high-temperature flue gas, preventing them from adhering to the exhaust pipe wall and clogging the pipe. In practical applications, the inorganic fiber filter cloth is replaced periodically. The inorganic fiber filter cloth is located inside the horizontal pipe to prevent the high-temperature flue gas discharged from the firing chamber from immediately contacting the inorganic fiber filter cloth, thus avoiding shortening its service life. Furthermore, adsorption and filtration at a slightly lower temperature will improve the filtration effect. In practical applications, a vertical pipe can also be connected at the waste heat gas inlet, i.e., the exhaust port, vertical pipe, horizontal pipe, waste heat gas inlet, and vertical pipe are sequentially connected. As is common sense, when there are multiple exhaust outlets, the exhaust pipe includes multiple vertical pipes and one horizontal pipe.

[0014] Preferably, a water tank is connected in series between the outlet of the hot water exchange pipe and the inlet of the cooling water pipe. The water tank is used to supply cooling water to the cooling water pipe; as is common knowledge, the water tank can be replenished with water to regulate the temperature of the cooling water flowing out of the hot water exchange pipe.

[0015] Furthermore, the firing chamber is equipped with a heating mechanism. The heating mechanism is conventional equipment, and conventional heating pipes can be selected, located on the inner wall of the tunnel kiln.

[0016] Furthermore, the flue gas reuse tunnel kiln is also equipped with an inlet gate and an outlet gate. The inlet gate and outlet gate are commercially available products used to seal this utility model. They are conventionally selected according to needs. In actual application, they can be lifting gates, flap gates, or other conventional gates. The specific installation method and usage method are conventional technologies and do not affect the understanding of this utility model by those skilled in the art.

[0017] As is common knowledge, the flue gas reuse tunnel kiln also includes the conventional structure of a conventional tunnel kiln, such as electrical mechanisms, sealing mechanisms, feeding mechanisms, and unloading mechanisms, which does not affect the understanding of the technological progress of this utility model by those skilled in the art.

[0018] Due to the application of the above technical solutions, the flue gas reuse tunnel kiln of this utility model has the following advantages: This utility model recovers and utilizes the heat generated in the firing chamber and cooling chamber by discharging the high-temperature flue gas generated in the firing chamber into the preheating chamber and then circulating the cooling water after cooling the product into the displacement chamber, thus avoiding energy waste, saving resources, and being highly practical; Furthermore, this utility model improves the structure of the existing tunnel kiln for introducing nitrogen gas, introducing it from the product outlet of the tunnel kiln and blowing it towards the product inlet, avoiding the firing flue gas from dispersing into the cooling chamber, and also forming a nitrogen-flue gas passage, which is conducive to the discharge of oily flue gas. At the same time, the cooling chamber can preheat the nitrogen gas, avoiding the direct introduction of nitrogen gas into the firing chamber and affecting the ambient temperature, effectively ensuring the firing effect; In addition, the firing flue gas is adsorbed and filtered and then used for preheating in the preheating chamber, which reduces the impact of the firing flue gas on the preheating materials while making better use of waste heat. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the flue gas reuse tunnel kiln in Example 1.

[0020] Figure 2 This is a schematic diagram of the firing chamber.

[0021] Figure 3 This is a schematic diagram of the structure of a horizontal pipe.

[0022] Figure 4 This is a schematic diagram of the flue gas reuse tunnel kiln in Example 2.

[0023] Figure 5 This is a schematic diagram of the firing chamber.

[0024] Figure 6 This is a schematic diagram of the cooling chamber.

[0025] The components include: replacement chamber 1, preheating chamber 2, firing chamber 3, cooling chamber 4, exhaust pipe 5, inorganic fiber filter cloth 6, water tank 7, inlet gate 8, outlet gate 9, isolation gate 10, heating mechanism 11, hot water exchange pipe 101, second nitrogen inlet 102, air outlet 103, waste heat gas inlet 201, waste heat gas outlet 202, exhaust port 301, nitrogen transmission port 302, first nitrogen inlet 401, cooling water pipe 402, vertical pipe 501, and horizontal pipe 502. Detailed Implementation

[0026] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings and preferred embodiments. All components in this utility model are existing products, and the specific connection methods and control methods are conventional technologies.

[0027] Taking graphite sintering as an example, in this invention, the graphite anode material to be fired sequentially passes through a displacement chamber, a preheating chamber, a firing chamber, and a cooling chamber. The displacement chamber is used to displace the furnace atmosphere to remove air carried in the furnace and by the graphite anode material, preventing oxidation and surface defects. The preheating chamber is used to preheat the graphite anode material, gradually increasing its temperature to avoid deformation or cracking caused by direct high-temperature firing. The firing chamber is used to fire the graphite anode material. High-temperature flue gas (containing oil and powder) generated during firing enters the preheating chamber through an exhaust pipe, utilizing the residual heat of the flue gas to preheat the material. Nitrogen gas enters the cooling chamber through a first nitrogen inlet and then enters the firing chamber. While cooling the fired product, the cooling chamber exchanges heat with the nitrogen gas, preheating the nitrogen gas before it enters the firing chamber. This prevents nitrogen gas from directly entering the firing chamber and affecting the ambient temperature, effectively ensuring the firing effect.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as "length," "width," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," and "outer" indicate orientations or positions based on the accompanying drawings and are for ease of description only, and should not be construed as limiting the scope of the invention. In this invention, the location of the inlet gate is the product inlet, and the location of the outlet gate is the product entrance. Example 1

[0029] like Figures 1 to 3 As shown:

[0030] A flue gas reuse tunnel kiln includes a replacement chamber 1, a preheating chamber 2, a firing chamber 3, and a cooling chamber 4 arranged sequentially.

[0031] The replacement chamber is equipped with a hot water pipe 101, a second nitrogen inlet 102, and an air outlet 103.

[0032] The preheating chamber is equipped with a waste heat gas inlet 201 and a waste heat gas outlet 202. In actual applications, the exhaust gas discharged from the waste heat gas outlet is conventionally treated, such as air purification treatment. At this time, the temperature is relatively low and the oil and powder content is small.

[0033] In this embodiment, the firing chamber is provided with three exhaust ports 302, which are respectively connected to the waste heat gas inlet through exhaust pipes 5. The exhaust pipes include vertical pipes 501 and horizontal pipes 502. Each of the three exhaust ports is connected to a vertical pipe, and the waste heat gas inlet is connected to a vertical pipe. The vertical pipes connected to the exhaust ports and the vertical pipes connected to the waste heat gas inlet are connected through horizontal pipes.

[0034] In this embodiment, an inorganic fiber filter cloth 6 is installed inside the horizontal tube. The inorganic fiber filter cloth has a cage structure, specifically a hollow cylindrical structure. A layer of inorganic fiber filter cloth is installed inside at 0.5m intervals. Conventional hooks are provided at both ends of the horizontal tube, and the two ends of the inorganic fiber filter cloth are hung on the hooks.

[0035] The cooling chamber is equipped with a first nitrogen inlet 401 and a cooling water pipe 402. The first nitrogen inlet is located on the rear side wall of the cooling chamber, i.e., the tunnel kiln outlet side wall. The cooling water pipe and the heat exchange water pipe are located on the inner side wall of the tunnel kiln, respectively. The inlet of the heat exchange water pipe is connected to the outlet of the cooling water pipe, and a water tank 7 is connected in series between the outlet of the heat exchange water pipe and the inlet of the cooling water pipe.

[0036] The flue gas reuse tunnel kiln is also equipped with an inlet gate 8, an outlet gate 9, and an isolation gate 10 between the replacement chamber and the preheating chamber.

[0037] In this utility model, the entrance gate 8, the exit gate 9, and the isolation gate 10 are commercially available products and can be conventionally selected according to needs. In actual application, they can be lifting gates, flap gates, or other conventional gates. The specific installation method and usage method are conventional technologies and do not affect the understanding of this utility model by those skilled in the art.

[0038] As is common knowledge, this utility model also includes the conventional structure of a conventional tunnel kiln, such as electrical mechanism, sealing mechanism, feeding mechanism, unloading mechanism, etc.; the firing chamber is equipped with a heating mechanism 11, which is a conventional device and can be selected from conventional heating tubes; conventional pumps or fans are conventionally installed on the gas pipeline and water pipeline to achieve circulation, which does not affect the understanding of the technical progress of this utility model by those skilled in the art. Example 2

[0039] Based on Embodiment 1, the difference in this embodiment is that isolation gates are respectively provided between the preheating chamber and the firing chamber, and between the firing chamber and the cooling chamber. The firing chamber is provided with a nitrogen transmission port 302, which is located on the inner wall at the junction of the cooling chamber and the firing chamber. The inner wall refers to the inner wall of the flue gas reuse tunnel kiln. The rest is the same, such as... Figures 4 to 6 As shown.

[0040] Application Examples

[0041] Using the flue gas reuse tunnel kiln of Example 1, taking the firing of graphite as an example, the usage method is as follows:

[0042] (1) Close the isolation gate between the displacement chamber and the preheating chamber, close the outlet gate, introduce nitrogen into the first nitrogen inlet, turn on the heating mechanism, and heat up the firing chamber;

[0043] (2) Open the inlet gate and send the crucible containing the raw materials into the replacement chamber through the existing trolley. Close the inlet gate and introduce nitrogen into the second nitrogen inlet for atmosphere replacement.

[0044] (3) After the atmosphere replacement is completed, the isolation gate between the replacement chamber and the preheating chamber is opened, and the raw materials enter the preheating chamber and are preheated by the hot gas transported from the firing chamber;

[0045] (4) The preheated raw materials are sent into the firing chamber. The tail nitrogen flow fills the firing chamber and the cooling chamber. Combined with the exhaust fan, the high temperature flue gas is filtered through the exhaust pipe from the exhaust port and then enters the preheating chamber.

[0046] (5) The fired products enter the cooling chamber, where they are cooled and heat exchanged by the nitrogen flow and cooling water. Hot nitrogen is introduced into the firing chamber, and the cooling water after cooling the fired products is introduced into the displacement chamber.

[0047] In step (3) above, after the raw material in the displacement chamber is sent into the preheating chamber, a batch of material can be added and removed, and this process can be repeated to achieve graphite firing.

[0048] Using the flue gas reuse tunnel kiln of Example 2, taking graphite firing as an example, the usage method is as follows:

[0049] (1) Close the isolation gates between the displacement chamber and the preheating chamber, the preheating chamber and the firing chamber, and the firing chamber and the cooling chamber, close the outlet gate, introduce nitrogen into the first nitrogen inlet, turn on the heating mechanism, and raise the temperature of the firing chamber;

[0050] (2) Open the inlet gate and send the crucible containing the raw materials into the replacement chamber through the existing trolley. Close the inlet gate and introduce nitrogen into the second nitrogen inlet for atmosphere replacement.

[0051] (3) After the atmosphere replacement is completed, the isolation gate between the replacement chamber and the preheating chamber is opened, and the raw materials enter the preheating chamber and are preheated by the hot gas transported from the firing chamber;

[0052] (4) After preheating, open the isolation gate between the preheating chamber and the firing chamber, send the raw material into the firing chamber, and the tail nitrogen flow into the firing chamber from the nitrogen transmission port. Combined with the exhaust fan, the high temperature flue gas is filtered through the exhaust pipe from the exhaust port and then enters the preheating chamber, resulting in better gas flow.

[0053] (5) The fired products enter the cooling chamber, where they are cooled and heat exchanged by the nitrogen flow and cooling water. Hot nitrogen is introduced into the firing chamber, and the cooling water after cooling the fired products is introduced into the displacement chamber.

[0054] In step (3) above, after the raw material in the displacement chamber is preheated, a batch of material can be added and removed, and this process can be repeated to achieve graphite firing.

[0055] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the principle of the present utility model, and these should also be considered to fall within the protection scope of the present utility model.

Claims

1. A tunnel kiln of the type with recycling of the fumes, characterized in that: The tunnel kiln comprises a replacement chamber, a preheating chamber, a firing chamber and a cooling chamber arranged in sequence, the replacement chamber is provided with a heat exchange water pipe, the preheating chamber is provided with a waste heat gas inlet and a waste heat gas outlet, the firing chamber is provided with a nitrogen gas transmission port and a smoke exhaust port, the smoke exhaust port is communicated with the waste heat gas inlet through a smoke exhaust pipe, and the cooling chamber is provided with a first nitrogen gas inlet and a cooling water pipe.

2. The tunnel kiln of claim 1, wherein: Isolation gates are arranged between the replacement chamber and the preheating chamber, the preheating chamber and the firing chamber and the firing chamber and the cooling chamber.

3. The tunnel kiln of claim 1, wherein: The nitrogen gas transmission port is located on the inner wall of the joint of the cooling chamber and the firing chamber.

4. The tunnel kiln of claim 1, wherein: The replacement chamber is provided with a second nitrogen gas inlet and an air outlet.

5. The tunnel kiln of claim 1, wherein: The number of the smoke exhaust ports is one or more.

6. The flue gas recycling tunnel kiln according to claim 1, characterized in that: Inorganic fiber filter cloth is arranged in the smoke exhaust pipe.

7. The flue gas recycling tunnel kiln according to claim 6, characterized in that: The smoke exhaust pipe comprises a vertical pipe and a horizontal pipe, the smoke exhaust port, the vertical pipe, the horizontal pipe and the waste heat gas inlet are communicated in sequence, and inorganic fiber filter cloth is arranged in the horizontal pipe.

8. The flue gas recycling tunnel kiln according to claim 1, characterized in that: A water tank is connected in series between the water outlet of the heat exchange water pipe and the water inlet of the cooling water pipe.

9. The flue gas recycling tunnel kiln according to claim 1, characterized in that: The firing chamber is provided with a heating mechanism.

10. The flue gas recycling tunnel kiln according to claim 1, characterized in that: The smoke gas recycling type tunnel kiln is also provided with an inlet gate and an outlet gate.

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