Oxygen-controlled low-nitrogen air-cooled gas hot blast stove

Abstract

The oxygen-control low-nitrogen air-cooled gas hot blast stove comprises a stove body and a combustor, the combustor is provided with a gas pipe and a combustion-supporting air pipe, the gas pipe is provided with an electric V-shaped ball valve and a turbine flowmeter, the combustion-supporting air pipe is provided with an electric V-shaped ball valve, an air flowmeter and a frequency conversion fan which are matched with a combustion-supporting air pipe, and the turbine flowmeter is provided with a turbine flowmeter. The furnace body is divided into an outer cylinder and an inner cylinder, a gas inlet pipe, a gas outlet pipe and a tail gas pipe are arranged on the furnace body, and the tail gas pipe is connected with the combustor. The electric V-shaped ball valves and the flow meters are arranged on the gas pipe and the combustion-supporting gas pipe on the combustor, so that the ratio of gas fuel to combustion-supporting air is strictly controlled according to the air amount needed by combustion, excessive air is reduced to the complete combustion limit, when gas is fully combusted, the gas and the supplied air generate a violent thermal chemical reaction, and the combustion effect is improved. O2 in the air is basically exhausted, so that low-oxygen and oxygen-controlled combustion in the whole process is realized.

Description

Technical Field

[0001] This invention relates to the field of low-NOx hot blast stove technology, and more particularly to an oxygen-controlled low-NOx air-cooled gas-fired hot blast stove. Background Technology

[0002] Currently, my country's lithium battery recycling and utilization has formed a relatively mature and fixed processing technology. Lithium battery recycling generally includes several main steps such as brine discharge, high-temperature pyrolysis, crushing and drying, and magnetic separation. Among these, the crushing and drying of waste lithium batteries is a crucial link in the comprehensive utilization of lithium batteries. The crushing and drying of lithium batteries must be carried out in a nitrogen-controlled oxygen environment to ensure that the batteries are crushed and dried while still charged in a safe, low-oxygen, and sealed space. Therefore, strict requirements for oxygen control are placed on the drying of materials related to lithium battery recycling.

[0003] Secondly, there are pharmaceutical intermediates such as tetracycline hydrochloride, including tetracycline hydrochloride and tetracycline base. These materials require drying using a low-temperature centrifugal atomization process with inert gas protection, following the principles of instantaneous desolvation, crystal form protection, and full-process oxygen control. Oxygen-controlled gas-fired heaters are the preferred heating equipment for drying these pharmaceutical intermediate raw materials.

[0004] In addition, many Chinese medicinal herbs and cash crops such as fruits and vegetables require oxygen-controlled drying processes, including dandelion, purslane, chrysanthemum, cordyceps, ginseng, and mushrooms. These materials may require controlled oxygen levels during drying to preserve their nutrients, color, and flavor; vitamins and pigments in fruits and vegetables may also be lost due to oxidation. Using oxygen-controlled hot air furnaces for heating and drying plays a positive role in ensuring the quality of these products.

[0005] Therefore, based on the market demand in the aforementioned fields, and after years of exploration, we have developed and launched an oxygen-controlled, low-nitrogen, air-cooled gas-fired hot air furnace. Summary of the Invention

[0006] The hot air furnace of this invention is a new type of hot air furnace product that integrates low oxygen control, market application, low nitrogen environmental protection, heat preservation and energy saving. Compared with other types of gas hot air furnaces on the market, this product has a unique low nitrogen oxygen control air-cooled product structure and has broad application prospects. Therefore, an oxygen control low nitrogen air-cooled gas hot air furnace is proposed.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: An oxygen-controlled, low-NOx air-cooled gas-fired hot air furnace includes a furnace body and a burner. The burner is equipped with a gas pipe and a combustion air duct. The gas pipe is equipped with an electric V-type ball valve and a turbine flow meter. The combustion air duct is equipped with an electric V-type ball valve, an air flow meter, and a variable frequency fan that are matched with the combustion air pipe. The furnace body is divided into an outer cylinder and an inner cylinder. The furnace body is equipped with an air inlet pipe, an air outlet pipe, and a tail gas pipe, and the tail gas pipe is connected to the burner.

[0008] Preferably, the electric V-type ball valve of the combustion-supporting air duct and the electric V-type ball valve of the gas pipeline are interlocked with a stepless controller, which can adjust the combustion-supporting air volume in a timely manner according to the change of gas flow, ensuring accurate oxygen control and combustion. The combustion-supporting air duct is connected to a variable frequency fan, and a diversion pipe is provided on the combustion-supporting air duct, and a control valve is provided on the diversion pipe, so that when the air volume is large and the demand is small, the excess air force can be discharged in time.

[0009] Preferably, the furnace body is equipped with a high-temperature resistant ceramic baffle, which is arranged at an angle to force the flue gas to flow upward, while the clean hot air is guided to circulate downward. The baffle angle is 30°~45° to avoid ash accumulation and ensure smooth airflow. At the same time, multiple sets of heat exchange flat steel plates of different lengths are arranged on the inner cylinder of the furnace body. The heat exchange flat steel plates facilitate the conduction of heat in the inner cylinder to a certain extent.

[0010] Preferably, the air inlet end of the air inlet pipe is connected to a centrifugal fan, and the air inlet pipe passes through the outer cylinder and extends into the interlayer between the outer cylinder and the inner cylinder. A spiral air duct is opened on the inner wall of the interlayer between the outer cylinder and the inner cylinder, and the spiral air duct extends to the air inlet end of the air outlet pipe. The air outlet pipe passes through one side of the bottom of the outer cylinder. By setting up a centrifugal fan, an air inlet pipe and an air outlet pipe, it is convenient to introduce room temperature cold air into the interlayer of the hot air furnace cylinder, forming a layer of air cooling protection for the inner cylinder combustion chamber. This can preheat the room temperature combustion air, and the preheated combustion air can then enter the burner and participate in combustion with the gas better.

[0011] Preferably, the exhaust pipe is divided into an outer exhaust pipe and an inner exhaust pipe. An induced draft fan and a circulating fan are respectively installed at both ends of the outer exhaust pipe. The air inlet end of the induced draft fan is connected to a connecting pipe that passes through the inner cylinder. At the same time, the exhaust gas usually floats upward. This is mainly because the exhaust gas temperature is high and the density is less than that of air. Therefore, it will move upward, making it easier to be drawn by the induced draft fan and transported to the location of use by the circulating fan.

[0012] Preferably, the air inlet of the circulating fan is connected to the external exhaust pipe and the air outlet pipe respectively through a three-way pipe, and the internal exhaust pipe of the air outlet of the circulating fan is Y-shaped, which facilitates the centralized collection of exhaust gas and preheated air and their mixing and dispersion delivery to the burner.

[0013] Preferably, the two ends of the Y-shaped internal exhaust pipe extend into the ventilation duct of the central spray gun of the burner and the area where the combustion gas and air enter the burner, respectively. Control valves are provided on both outlet ends of the Y-shaped internal exhaust pipe. The central spray gun in the burner is located in the middle of the pipe, and its surface is fitted with and fixedly connected with helical blades. The outer ring surface of the helical blades is sealed and fixed to the inner wall of the pipe. By setting the Y-shaped exhaust pipe, part of the mixed exhaust gas is mixed with the combustion air and combustion gas again and enters the burner for combustion. Another part of the exhaust gas enters the pipe where the spray gun is located, creating turbulence in the combustion area, increasing the air flow in the combustion area, facilitating combustion, and reducing oxygen residue.

[0014] Preferably, a collection pipe is provided on the side of the furnace body away from the burner, and the gas collection end of the collection pipe passes through the outer cylinder and extends into the inner cylinder. The inner wall of the gas collection end of the collection pipe is provided with multiple steel umbrella-shaped rings. By providing steel umbrella-shaped rings, it is convenient for the low-oxygen and low-nitrogen air after combustion to move along the proper track of the steel umbrella-shaped rings.

[0015] Preferably, the collection pipe is provided with a cooling pipe, and the cooling pipe is provided with cooling and temperature-regulating circulating flue gas. By providing the cooling pipe, the cooling and temperature-regulating circulating flue gas in the pipe can be cooled and mixed with low-oxygen and low-nitrogen air in the collection pipe, which is convenient for subsequent use.

[0016] The present invention has the following beneficial effects: 1. This invention provides an electric V-type ball valve and flow meter on the gas pipe and combustion air pipe of the burner. This allows for strict control of the gas fuel to combustion air ratio according to the amount of air required for combustion, reducing excess air to the limit of complete combustion. When the gas is fully combusted, it produces a vigorous thermochemical reaction with the supplied air, and the O2 content in the air is basically consumed, thereby achieving low-oxygen controlled combustion throughout the entire process.

[0017] 2. This invention preheats the combustion air by mixing a portion of the low-temperature flue gas from the furnace outlet with the combustion air from the burner before it enters the furnace. This method can greatly reduce the oxygen content in the high-temperature combustion zone of the furnace. In addition, another low-temperature flue gas from the furnace outlet is introduced into the furnace from the dead corner of the flame diffusion cone at the end of the combustion chamber, which strongly disturbs the combustion flue gas in the combustion chamber and forms turbulence. The temperature distribution in the combustion chamber is more uniform, avoiding local overheating. The low-temperature circulating flue gas mixed into the furnace can also reduce the temperature of the entire furnace, avoiding and reducing the generation of high-temperature NOx. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the front section structure of the hot blast stove proposed in this invention; Figure 2 This is a schematic diagram of the burner structure proposed in this invention; Figure 3 This is a schematic diagram of the side section structure of the furnace body.

[0019] In the diagram: 1. Furnace body; 2. Burner; 3. Gas pipe; 4. Combustion air duct; 5. Electric V-type ball valve; 6. Turbine flow meter; 7. Air flow meter; 8. Variable frequency fan; 9. Outer cylinder; 10. Inner cylinder; 11. Inlet pipe; 12. Outlet pipe; 13. External exhaust pipe; 14. Internal exhaust pipe; 15. Diverter pipe; 16. Baffle; 17. Centrifugal fan; 18. Exhaust fan; 19. Circulating fan; 20. Collection pipe; 21. Circular ring; 22. Cooling pipe. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Example 1 Reference Figure 1-2 A controlled oxygen, low nitrogen, air-cooled gas-fired hot air furnace includes a furnace body 1 and a burner 2. The burner 2 is equipped with a gas pipe 3 and a combustion air duct 4. The gas pipe 3 is equipped with an electric V-type ball valve 5 and a turbine flow meter 6. The combustion air duct 4 is equipped with an electric V-type ball valve 5, an air flow meter 7, and a variable frequency fan 8 that are matched with the combustion air duct 3. The electric V-type ball valve 5 of the combustion air duct 4 and the electric V-type ball valve 5 of the gas pipe 3 are interlocked by a stepless controller, which can adjust the combustion air volume in a timely manner according to the change of gas flow, ensuring accurate oxygen-controlled combustion. The combustion air duct 4 is connected to the variable frequency fan 8.

[0023] The combustion-supporting air duct 4 is equipped with a diversion pipe 15, and the diversion pipe 15 is equipped with a control valve to facilitate the timely discharge of excess air when the air volume is large and the demand is small.

[0024] Furthermore, the central spray gun in the burner 2 is located in the middle of the pipe, and its surface is fitted with and fixedly connected with a spiral blade. The outer ring surface of the spiral blade is sealed and fixed to the inner wall of the pipe. The spiral blade is a stainless steel high-pitch conveying blade with a polished surface and a spray gun sleeve installed in the center.

[0025] The furnace body 1 is divided into an outer cylinder 9 and an inner cylinder 10. A high-temperature resistant ceramic baffle 16 is installed inside the furnace body 1, and the baffle 16 is arranged at an angle to force the flue gas to flow upward, while the hot gas is guided to circulate downward. The angle of the baffle 16 is 30°~45° to avoid ash accumulation and ensure smooth airflow. The baffle 16 has a wave-shaped design to facilitate the deceleration of the direct hot gas. At the same time, multiple sets of heat exchange flat steel plates of different lengths are arranged on the inner cylinder 10 of the furnace body 1. The heat exchange flat steel plates facilitate the heat conduction in the inner cylinder 10 to a certain extent.

[0026] In this embodiment, by installing an electric V-type ball valve 5 and a flow meter on the gas pipe 3 and the combustion air pipe 3 on the burner 2, it is convenient to strictly control the ratio of gas fuel to combustion air according to the amount of air required for combustion, reduce excess air to the limit of complete combustion, and when the gas is fully combusted, it produces a fierce thermochemical reaction with the supplied air, and the O2 content in the air is basically consumed, thereby realizing low oxygen controlled combustion throughout the process.

[0027] Example 2 Reference Figure 1-3 The furnace body 1 is respectively provided with an air inlet pipe 11, an air outlet pipe 12 and a tail gas pipe. The air inlet end of the air inlet pipe 11 is connected to a centrifugal fan 17, and the air inlet pipe 11 passes through the outer cylinder 9 and extends into the interlayer between the outer cylinder 9 and the inner cylinder 10. The inner wall of the interlayer between the outer cylinder 9 and the inner cylinder 10 is provided with a spiral air duct, and the spiral air duct extends to the air inlet end of the air outlet pipe 12. The air outlet pipe 12 passes through one side of the bottom of the outer cylinder 9. By setting up the centrifugal fan 17, the air inlet pipe 11 and the air outlet pipe 12, it is convenient to introduce room temperature cold air into the interlayer of the hot air furnace body, forming a layer of air cooling protection for the combustion chamber of the inner cylinder 10, which can preheat the room temperature combustion air. The preheated combustion air then enters the burner 2, and can better participate in combustion with the gas.

[0028] The exhaust pipe is connected to the burner 2. The exhaust pipe is divided into an outer exhaust pipe 13 and an inner exhaust pipe 14. The outer exhaust pipe 13 is equipped with an induced draft fan 18 and a circulating fan 19 at both ends. The air inlet of the induced draft fan 18 is connected to a connecting pipe that passes through the inner cylinder 10. At the same time, the exhaust gas usually floats upward. The main reason is that the exhaust gas temperature is high and the density is less than that of air. Therefore, it will move upward, making it easier to be drawn by the induced draft fan 18 and transported to the location of use through the circulating fan 19.

[0029] Furthermore, the air inlet of the circulating fan 19 is connected to the outer exhaust pipe 13 and the exhaust pipe 12 respectively through a three-way pipe, and the inner exhaust pipe 14 of the exhaust end of the circulating fan 19 is arranged in a Y-shape, which facilitates the centralized collection of exhaust gas and preheated air and their mixing and dispersion delivery to the burner 2.

[0030] Furthermore, the two ends of the Y-shaped inner exhaust pipe 14 extend into the ventilation duct of the central spray gun of the burner 2 and the area where the combustion gas and air enter the burner 2, respectively. A funnel pipe is installed in the ventilation duct of the central spray gun of the burner 2 to facilitate the concentration of firepower to burn the air, form a combustion zone, and reduce the oxygen content in the combustion air. Control valves are installed on both outlet ends of the Y-shaped inner exhaust pipe 14. By setting the Y-shaped exhaust pipe, part of the mixed exhaust gas is mixed with the combustion air and combustion gas again and enters the burner 2 for combustion. Another part of the exhaust gas enters the pipe where the spray gun is located, creating turbulence in the combustion zone, increasing the air flow in the combustion zone, facilitating combustion, and reducing oxygen residue.

[0031] A collection pipe 20 is provided on the side of the furnace body 1 away from the burner 2, and the gas collection end of the collection pipe 20 passes through the outer cylinder 9 and extends into the inner cylinder 10. The inner wall of the gas collection end of the collection pipe 20 is provided with a plurality of steel umbrella-shaped rings 21. By providing steel umbrella-shaped rings 21, it is convenient for the low-oxygen and low-nitrogen air after combustion to move along the proper track of the steel umbrella-shaped rings 21.

[0032] Furthermore, a cooling pipe 22 is provided on the collection pipe 20, and the cooling pipe is filled with cooling and temperature-regulating circulating flue gas. By providing the cooling pipe 22, the cooling and temperature-regulating circulating flue gas in the pipe can be cooled and mixed with low-oxygen and low-nitrogen air in the collection pipe 20, which is convenient for subsequent use.

[0033] In this embodiment, by mixing a portion of the exhaust gas from furnace body 1 with the combustion air from burner 2 before entering the furnace, the combustion air can be preheated. This method can greatly reduce the oxygen content in the high-temperature combustion zone of the furnace. In addition, another exhaust gas is organized to enter the furnace from the dead corner of the flame diffusion cone at the end of the combustion chamber, which causes strong disturbance of the combustion flue gas in the combustion chamber to form turbulence. The temperature distribution in the combustion chamber is more uniform, avoiding local overheating. The low-temperature circulating flue gas mixed into the furnace can also reduce the temperature of the entire furnace, avoiding and reducing the generation of high-temperature NOx.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A controlled-oxygen, low-NOx air-cooled gas-fired hot air furnace, characterized in that: The furnace includes a furnace body (1) and a burner (2). The burner (2) is equipped with a gas pipe (3) and a combustion air pipe (4). The gas pipe (3) is equipped with an electric V-type ball valve (5) and a turbine flow meter (6). The combustion air pipe (4) is equipped with an electric V-type ball valve (5), an air flow meter (7) and a variable frequency fan (8) that are matched with the combustion air pipe (3). The furnace body (1) is divided into an outer cylinder (9) and an inner cylinder (10). The furnace body (1) is equipped with an air inlet pipe (11), an air outlet pipe (12) and a tail gas pipe, and the tail gas pipe is connected to the burner (2).

2. The oxygen-controlled, low-NOx air-cooled gas-fired hot blast stove according to claim 1, characterized in that: The electric V-type ball valve (5) of the combustion air duct (4) and the electric V-type ball valve (5) of the gas pipeline (3) are interlocked by a stepless controller, and the combustion air duct (4) is connected to the variable frequency fan (8). A diversion pipe (15) is provided on the combustion air duct (4), and a control valve is provided on the diversion pipe (15).

3. The oxygen-controlled, low-NOx air-cooled gas-fired hot blast stove according to claim 1, characterized in that: The furnace body (1) is equipped with a high-temperature resistant ceramic baffle (16), and the baffle (16) is arranged at an angle. At the same time, multiple sets of heat exchange flat steel sheets of different lengths are arranged on the inner cylinder (10) of the furnace body (1).

4. The oxygen-controlled, low-NOx air-cooled gas-fired hot blast stove according to claim 1, characterized in that: The air inlet pipe (11) is connected to a centrifugal fan (17) at its air inlet end. The air inlet pipe (11) passes through the outer cylinder (9) and extends into the interlayer between the outer cylinder (9) and the inner cylinder (10). A spiral air duct is provided on the inner wall of the interlayer between the outer cylinder (9) and the inner cylinder (10). The spiral air duct extends to the air inlet end of the air outlet pipe (12). The air outlet pipe (12) passes through one side of the bottom of the outer cylinder (9).

5. The oxygen-controlled, low-NOx air-cooled gas-fired hot air furnace according to claim 1, characterized in that: The exhaust pipe is divided into an outer exhaust pipe (13) and an inner exhaust pipe (14). The outer exhaust pipe (13) is equipped with an induced draft fan (18) and a circulating fan (19) at both ends, and the air inlet end of the induced draft fan (18) is connected to a connecting pipe that passes through the inner cylinder (10).

6. The oxygen-controlled, low-nitrogen, air-cooled gas-fired hot blast stove according to claim 5, characterized in that: The air inlet of the circulating fan (19) is connected to the outer exhaust pipe (13) and the air outlet pipe (12) respectively through a three-way pipe, and the inner exhaust pipe (14) of the air outlet of the circulating fan (19) is arranged in a Y-shape.

7. The oxygen-controlled, low-NOx air-cooled gas-fired hot blast stove according to claim 6, characterized in that: The two ends of the Y-shaped internal exhaust pipe (14) extend into the ventilation duct of the central spray gun of the burner (2) and the area where the gas and air enter the burner (2), respectively, and control valves are provided on both outlet ends of the Y-shaped internal exhaust pipe (14).

8. The oxygen-controlled, low-nitrogen, air-cooled gas-fired hot blast stove according to claim 7, characterized in that: The central spray gun in the burner (2) is located in the middle of the pipe, and its surface is fitted with and fixedly connected with a spiral blade, the surface of which is sealed and fixed to the inner wall of the pipe.

9. The oxygen-controlled, low-NOx air-cooled gas-fired hot blast stove according to claim 1, characterized in that: A collection pipe (20) is provided on the side of the furnace body (1) away from the burner (2), and the gas collection end of the collection pipe (20) passes through the outer cylinder (9) and extends into the inner cylinder (10). Multiple steel umbrella-shaped rings (21) are provided on the inner wall of the gas collection end of the collection pipe (20).

10. The oxygen-controlled, low-NOx air-cooled gas-fired hot blast stove according to claim 9, characterized in that: The collection pipe (20) is provided with a cooling pipe (22), and the cooling pipe is provided with cooling and temperature-regulating circulating flue gas.

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