Nitrogen heating device utilizing flue gas waste heat

Abstract

The utility model relates to the technical field of tin bath nitrogen heating, and particularly discloses a nitrogen heating device utilizing flue gas waste heat, which comprises an air separation tower, a nitrogen heating device and a nitrogen heating device, the heat exchanger is connected with the air separation tower through a first pipeline, and a first stop valve is arranged on the first pipeline; the tin bath gas distribution chamber is connected with the heat exchanger through a second pipeline, and a second stop valve is arranged on the second pipeline; the kiln is connected with the heat exchanger through a three-way pipeline, the flue gas enters the heat exchanger from the kiln through the three-way pipeline after being treated, and an automatic regulating valve is arranged on the three-way pipeline. According to the utility model, redundant flue gas waste heat is used for heating nitrogen, energy is not needed in the nitrogen heating process, the nitrogen heating temperature can be controlled only by controlling the flue gas inlet amount, the flue gas inlet amount is automatically adjusted by obtaining the nitrogen temperature through the automatic adjusting valve arranged at the flue gas inlet, and the purpose of stable temperature is achieved; the structure is simple and complex operation is not needed.

Description

Technical Field

[0001] The utility model relates to the technical field of tin bath nitrogen heating, in particular to a nitrogen heating device utilizing flue gas waste heat. Background Art

[0002] In the precise and critical industry of cover glass manufacturing, extremely stringent requirements are placed on the use of gases, particularly high-purity nitrogen and relatively high-purity oxygen. They play an indispensable role in the entire production process, especially in the operation of the tin bath, where high-purity nitrogen is crucial.

[0003] The tin bath, a core piece of equipment in cover glass manufacturing, is filled with liquid tin. To prevent direct contact between the liquid tin and oxygen in the air, which could lead to oxidation and potentially affect product quality, a large amount of high-purity nitrogen is continuously introduced into the bath as a protective gas. This nitrogen acts as an invisible barrier, ensuring the purity of the liquid tin within.

[0004] However, to maintain a certain operating temperature, the tin bath requires continuous heating with electricity. The nitrogen produced from the air separation tower typically maintains a temperature between 10 and 25°C, making it a low-temperature gas for the high-temperature tin bath. When large quantities of low-temperature nitrogen are injected into the tin bath, the electric heating system must increase its power to maintain a stable temperature. This undoubtedly increases energy consumption and production costs. Furthermore, the kiln, a crucial piece of equipment for melting raw materials into molten glass, generates large quantities of high-temperature flue gases during the natural gas combustion process. This flue gas contains a significant amount of heat, but currently, it is not being effectively utilized, resulting in a significant waste of resources.

[0005] For example, a Chinese patent application numbered 201921303194.7, published on August 12, 2019, discloses a device for activating molecular sieves using waste heat steam and / or electrically heated contaminated nitrogen. The device comprises an air separation tower (1), a heating device, a purification device, and a venting device (5) connected in sequence. The air separation tower (1) is capable of treating industrial waste gas and providing contaminated nitrogen to the heating device; an electric heater, a central pipe (7), and a steam heater (4) are connected in parallel in the heating device, and the steam heater (4) is connected to waste heat steam through a waste heat steam pipe (6); and the purification device contains molecular sieves.

[0006] The inventors of the present application have discovered that this device for activating molecular sieves using waste heat steam and / or electrically heated contaminated nitrogen does not have an automatic regulating valve to adjust the intake volume of flue gas, cannot achieve temperature stability, and is not combined with a tin bath to achieve the purpose of reducing the electric heating power of the tin bath.

[0007] In order to solve the above problems, it is urgent to develop a nitrogen heating device that can automatically adjust the flue gas intake and reduce the electric heating power of the tin bath by utilizing the waste heat of the flue gas for heating. Utility Model Content

[0008] The main purpose of the utility model is to provide a nitrogen heating device that utilizes the waste heat of flue gas, which utilizes the excess waste heat of flue gas to heat the nitrogen. No energy is required in the nitrogen heating process, and the nitrogen heating temperature can be controlled by simply controlling the flue gas intake volume. By arranging an automatic regulating valve at the flue gas inlet, the flue gas intake volume can be automatically adjusted by obtaining the nitrogen temperature, thereby achieving the purpose of temperature stability. The utility model has a simple structure and does not require complicated operation.

[0009] According to one aspect of the present invention, a nitrogen heating device utilizing waste heat from flue gas is provided, comprising:

[0010] An air separation tower, wherein a first pipeline for conveying nitrogen is provided on the air separation tower;

[0011] A heat exchanger is connected to the air separation tower via a first pipeline, and a first stop valve is provided on the first pipeline;

[0012] The tin bath gas distribution chamber is connected to the heat exchanger via a second pipeline, and a second stop valve is provided on the second pipeline;

[0013] The kiln is connected to the heat exchanger through a three-way pipe. After being treated, the flue gas enters the heat exchanger from the kiln through the three-way pipe. An automatic regulating valve is provided on the three-way pipe.

[0014] According to an embodiment of the present invention, the first pipeline and the second pipeline are connected via a bypass pipeline, and a bypass valve is provided on the bypass pipeline.

[0015] According to an embodiment of the present invention, a pressure gauge is provided on the second pipeline, and the pressure gauge is used to measure the pressure of nitrogen.

[0016] According to an embodiment of the present invention, a first temperature detection component is further provided on the three-way pipe, and the first temperature detection component is used to measure the temperature of the flue gas before entering the heat exchanger.

[0017] According to an embodiment of the present invention, a second temperature detection component is further provided on the second pipeline, and the second temperature detection component is used to measure the temperature of the nitrogen after leaving the heat exchanger.

[0018] According to one embodiment of the present invention, the nitrogen heating device also includes a desulfurization and denitrification system, which is connected to the kiln through a three-way pipe. The desulfurization and denitrification system is connected to the heat exchanger through a third pipe, and a third stop valve is provided on the third pipe.

[0019] According to one embodiment of the present invention, the heat exchanger is a tubular heat exchanger.

[0020] According to one embodiment of the present invention, there are multiple heat exchangers.

[0021] According to one embodiment of the present invention, the first temperature detection component and the second temperature detection component are thermometers and / or thermocouples and / or temperature sensors.

[0022] According to one embodiment of the present invention, the nitrogen heating device further includes an alarm component, which is disposed on the first pipeline and / or the second pipeline and / or the third pipeline and / or the bypass pipeline and / or the three-way pipeline.

[0023] According to an embodiment of the present invention, a nitrogen heating device utilizing flue gas waste heat is used to heat nitrogen. No energy is required in the nitrogen heating process. The nitrogen heating temperature can be controlled by simply controlling the flue gas intake volume. An automatic regulating valve is provided at the flue gas inlet, so that the flue gas intake volume can be automatically adjusted by obtaining the nitrogen temperature, thereby achieving temperature stability. The device has a simple structure and does not require complicated operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some implementation cases of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A schematic diagram showing a nitrogen heating device utilizing flue gas waste heat according to an exemplary embodiment of the present invention

[0026] The reference numerals in the figures are described as follows:

[0027] 1. Air separation tower; 2. Heat exchanger; 3. Tin bath gas distribution chamber; 4. Kiln; 5. First pipeline; 6. Second pipeline; 7. Bypass pipeline; 8. Three-way pipeline; 9. First stop valve; 10. Second stop valve; 11. Bypass valve; 12. Pressure gauge; 13. First temperature detection component; 14. Second temperature detection component; 15. Desulfurization and denitrification system; 16. Third pipeline; 17. Third stop valve; 18. Automatic regulating valve. DETAILED DESCRIPTION

[0028] The detailed description of the following embodiments is used to illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention. The present invention can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0029] The present invention provides these embodiments to make this disclosure thorough and complete, and to fully convey the scope of the present invention to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangements of parts and steps, material components, numerical expressions, and numerical values described in these embodiments should be interpreted as merely exemplary and not as limiting.

[0030] It should be noted that, in the description of this utility model, unless otherwise specified, "plurality" means greater than or equal to two; terms such as "upper," "lower," "left," "right," "inner," and "outer" indicating directions or positional relationships are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on this utility model. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intervening device between the specific device and the first or second device.

[0032] All terms used in this utility model have the same meaning as those understood by those of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0033] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, these technologies, methods, and equipment should be considered part of the specification.

[0034] like Figure 1 As shown, the present invention proposes a nitrogen heating device utilizing waste heat of flue gas, which comprises:

[0035] Air separation tower 1, air enters the air separation tower 1 and is separated according to the boiling point to obtain nitrogen. The air separation tower 1 is provided with a first pipeline 5 for transporting nitrogen;

[0036] Heat exchanger 2, heat exchanger 2 is connected to air separation tower 1 through first pipeline 5, nitrogen is transported from air separation tower 1 to heat exchanger 2 through first pipeline 5, and first stop valve 9 for regulating nitrogen inlet amount from air separation tower 1 to heat exchanger 2 is provided on first pipeline 5;

[0037] The tin bath gas distribution chamber 3 is connected to the heat exchanger 2 via a second pipe 6. Nitrogen heated by the flue gas waste heat as described below is transported to the tin bath gas distribution chamber 3 via the second pipe 6. The second pipe 6 is provided with a second stop valve 10 for regulating the nitrogen output from the heat exchanger 2 to the tin bath gas distribution chamber 3.

[0038] The kiln 4 is connected to the heat exchanger 2 through a three-way pipe 8. After being treated, the flue gas enters the heat exchanger 2 from the kiln 4 through the three-way pipe 8 to heat the nitrogen. The three-way pipe 8 is provided with an automatic regulating valve 18 for adjusting the flue gas intake amount from the kiln 4 to the heat exchanger 2.

[0039] Air separation tower 1, also known as air separation distillation tower, is a device that separates the components by heating the mixed gas to separate them according to the difference in boiling points.

[0040] The arrows in the figure indicate the direction of gas flow.

[0041] In the nitrogen heating device utilizing flue gas waste heat according to an embodiment of the present invention, the heating device primarily comprises an air separation tower 1, a heat exchanger 2, a tin bath gas distribution chamber 3, and a kiln 4. The air separation tower 1 provides fractionated nitrogen, the kiln 4 provides high-temperature flue gas, the heat exchanger 2 uses the high-temperature flue gas as a heat source to heat the nitrogen, and the tin bath gas distribution chamber 3 stores nitrogen, a protective gas. Molten tin is highly susceptible to oxidation in high-temperature environments, so the tin bath must be filled with nitrogen to prevent oxidation.

[0042] In some specific embodiments, the automatic regulating valve 18 adjusts the flue gas flow rate by varying the valve opening based on the real-time nitrogen temperature. The flue gas intake is automatically adjusted based on the real-time nitrogen temperature, achieving precise temperature control. Specifically, when the nitrogen temperature falls below a preset setpoint, the valve automatically increases the flue gas intake. This is because increasing the flue gas intake improves heating efficiency, allowing the nitrogen temperature to quickly return to the desired temperature range. Conversely, when the nitrogen temperature rises above the setpoint, the automatic regulating valve rapidly reduces the flue gas intake. This prevents the nitrogen temperature from overheating, which could cause equipment damage or safety hazards. By reducing the flue gas intake, the valve effectively lowers the nitrogen temperature, ensuring it remains within a safe temperature range. The immediate response of the automatic regulating valve 18 ensures rapid system response and stability. Based on a PID control algorithm, the automatic regulating valve 18 precisely regulates both nitrogen and flue gas flows. Its high degree of automation reduces errors due to manual intervention, significantly improving control accuracy and stability.

[0043] In some specific embodiments, in order to prevent the heat exchanger 2 from being unable to supply nitrogen due to a malfunction, the first pipeline 5 and the second pipeline 6 are connected by a bypass pipeline 7, and a bypass valve 11 is provided on the bypass pipe. The first pipeline 5 and the second pipeline 6 are respectively connected to the main pipelines of the heat exchanger 2, and the bypass pipeline 7 is connected on the side of the main pipeline, which can realize the branching of the flow rate, so that when the nitrogen flows in the pipeline, it can flow to different devices or containers through the bypass pipeline 7. The bypass pipeline 7 can also merge two or more pipelines into one pipeline to achieve the merging and mixing of the flow rates. This is very necessary for controlling the flow rate to ensure that the quantity and flow rate of the nitrogen in the connected equipment or container meet the requirements.

[0044] The bypass pipe 7 is typically smaller than the main pipe, allowing for more flexible placement between main pipes to accommodate varying space and installation requirements. By adjusting the size, angle, length, and direction of the bypass pipe 7, the flow rate and pressure in the main pipe can be controlled, achieving precise flow control and regulation.

[0045] Bypass valve 11 can adjust the flow and pressure of nitrogen by adjusting the degree of valve opening. Bypass valve 11 plays an important role when the flow or pressure in the pipeline system needs to be adjusted. It can also prevent the backflow of nitrogen in the pipeline by closing the valve. When replacing or repairing equipment, bypass pipeline 7 can serve as a backup pipeline to isolate equipment that needs repair to ensure the normal operation of the system. Preferably, bypass valve 11 can be a self-operated pressure differential control valve, which can also save energy and maintenance costs.

[0046] On the basis of the above embodiment, a pressure gauge 12 is provided on the second pipeline 6, and the pressure gauge 12 is used to measure the pressure of the nitrogen. The pressure gauge 12 can display the pressure of the nitrogen in the second pipeline 6, that is, before entering the tin bath gas distribution chamber 3, in real time, which is very important for understanding the nitrogen supply status. By observing the pressure gauge 12, changes in the nitrogen pressure can be discovered in time, so that corresponding measures can be taken to ensure the stability of the nitrogen supply. The pressure gauge 12 can also serve as an early warning. When the nitrogen pressure reaches or exceeds a specific value, the pressure gauge 12 will issue an alarm or signal to remind the operator to take corresponding measures to prevent the equipment from being over-pressurized, thereby avoiding possible accidents. In some embodiments, the pressure gauge 12 can be connected to the alarm component and then electrically connected to the control system to achieve control of the nitrogen pressure.

[0047] Furthermore, checking the nitrogen pressure before entering the tin bath gas distribution chamber 3 ensures a safe operating environment. If the nitrogen pressure is abnormal, the operator can react promptly and avoid working in a hazardous environment. By monitoring the nitrogen pressure, equipment damage due to overpressure or underpressure can be avoided, thereby extending the service life of the equipment.

[0048] In some specific embodiments, the second pipe 6 also has a thermal insulation function to ensure that the temperature of the nitrogen entering the tin bath gas distribution chamber 3 does not drop significantly. Pipeline insulation can significantly reduce heat loss during nitrogen transportation, lowering energy consumption. Pipeline insulation measures can effectively prevent energy loss, reducing energy waste and emissions. Pipeline insulation helps maintain a stable gas temperature in the pipeline, reducing transmission energy losses caused by temperature drops, thereby improving transportation efficiency.

[0049] In some specific embodiments, to achieve thermal insulation for the second pipe 6, an insulation layer is provided on the outer circumference of the pipe wall. This insulation layer needs to have a low thermal conductivity to reduce the impact of heat conduction on the nitrogen temperature. Suitable pipe insulation materials include aluminum silicate wool, polyurethane, silicate fiber, aerogel, and cold storage materials. In addition, spray insulation or electric heating insulation can also be used. In actual production, the appropriate insulation method can be adopted based on economic costs, technical requirements, and equipment requirements.

[0050] In some specific embodiments, the three-way pipe 8 is further provided with a first temperature detection assembly 13 for measuring the temperature of the flue gas before it enters the heat exchanger 2. By measuring the temperature of the nitrogen gas before it enters the heat exchanger 2, the stability of the internal environment of the equipment can be ensured, thereby ensuring production accuracy. Monitoring the nitrogen temperature helps prevent safety issues caused by abnormal temperatures such as overheating or overcooling of the equipment. By adjusting the temperature promptly, dangerous accidents such as equipment damage and fire can be avoided.

[0051] Based on the above embodiment, the second pipeline 6 is further provided with a second temperature detection assembly 14, which is used to measure the temperature of the nitrogen gas after it leaves the heat exchanger 2. The temperature data of the nitrogen gas after leaving the heat exchanger 2 provides an important reference for optimizing device performance. If the temperature is too high or too low, it may indicate an operational problem or the need for adjustment. By measuring the gas temperature, it is possible to ensure that the nitrogen gas reaches the desired heating effect when it leaves the heat exchanger 2, thereby ensuring the heat exchange effect.

[0052] In some specific embodiments, the nitrogen heating device further includes a desulfurization and denitrification system 15, which is connected to the kiln 4 via a three-way pipe 8. The desulfurization and denitrification system 15 is further connected to the heat exchanger 2 via a third pipe 16, and a third shut-off valve 17 is provided on the third pipe 16. The desulfurization and denitrification system 15 is used to desulfurize and denitrify the flue gas in the kiln 4. The desulfurization and denitrification system 15 is also connected to the heat exchanger 2 via the third pipe 16. After the flue gas enters the heat exchanger 2 and completes heat exchange, it enters the desulfurization and denitrification system 15 through the third pipe 16, where it is purified and treated, thereby reducing environmental pollution. The third shut-off valve 17 is used to regulate the nitrogen output from the heat exchanger 2 to the desulfurization and denitrification system 15.

[0053] Based on the above embodiment, to ensure that heat exchanger 2 can withstand high-temperature flue gas and prevent clogging, heat exchanger 2 is a tubular heat exchanger 2. Tubular heat exchanger 2 achieves temperature regulation through heat exchange between the fluid flowing within the tube and the fluid flowing outside the tube, and generally has a high heat exchange efficiency. Compared with other types of heat exchangers 2, tubular heat exchanger 2 can provide a larger heat exchange area per unit volume, saving space. In this application, tubular heat exchanger 2 can be manufactured using corrosion-resistant and high-temperature resistant materials such as stainless steel, titanium, and copper alloy. It is suitable for processing high-temperature flue gas, can withstand high temperatures and pressures, and is suitable for extreme working conditions.

[0054] In some specific embodiments, there are multiple heat exchangers 2. Multiple heat exchangers 2 can be used in series or in parallel to improve the overall heat exchange efficiency. Multiple heat exchangers 2 provide more configuration options and can adjust the heat exchange process according to different heat loads and process requirements. When multiple heat exchangers 2 are provided in the device, if one of the heat exchangers 2 fails, the other heat exchangers 2 can continue to operate, thereby improving the reliability and continuity of the device. In a parallel configuration, multiple heat exchangers 2 can share the flow rate of nitrogen, thereby reducing the pressure of a single heat exchanger 2.

[0055] Based on the above embodiments, the first temperature detection component 13 and the second temperature detection component 14 are thermometers and / or thermocouples and / or temperature sensors. Thermometers are fast and accurate, with high reading accuracy. Due to their low heat capacity and small size, thermocouples respond quickly to temperature changes, can respond within hundreds of milliseconds, and have a wide temperature measurement range. For example, J-type thermocouples can measure from -40 to 760°C, K-type thermocouples can measure from -40 to 1200°C, and N-type thermocouples can measure from -196 to 370°C, which are suitable for most practical temperature ranges, including industrial environments. Temperature sensors can convert the temperature and relative humidity in the environment into corresponding standard analog signals, with an accuracy of even 0.03°C. Temperature sensors also have a variety of contact and non-contact measurement methods that can adapt to different measurement objects and scenarios. In actual production, the appropriate type can be selected according to the specific application scenario and needs to achieve accurate, fast, and stable temperature measurement and control.

[0056] In some specific embodiments, the nitrogen heating device further includes an alarm assembly, which is disposed on the first pipeline 5, / or the second pipeline 6, / or the bypass pipeline 7, and / or the tee pipeline 8. When the alarm assembly is disposed on the first pipeline 5, it can monitor the nitrogen flow between the air separation tower 1 and the heat exchanger 2; when the alarm assembly is disposed on the second pipeline 6, it can monitor the nitrogen flow between the heat exchanger 2 and the tin bath gas distribution chamber 3; when the alarm assembly is disposed on the bypass pipeline 7, it can ensure device stability by monitoring the flow within the main pipeline; and when the alarm assembly is disposed on the tee pipeline 8, it can monitor the flue gas flow within the main pipeline. If the monitoring results are abnormal, the alarm assembly is controlled to sound an alarm, reminding the operator to adjust the gas flow, thereby ensuring operational and production safety.

[0057] Based on the above embodiment, the flue gas outlet of kiln 4 is equipped with one or more of a high-temperature gravity dust collector, an electrostatic dust collector, and a bag filter. The dust collector effectively removes particulate matter from the flue gas, reducing environmental pollution. The flue gas from kiln 4 enters heat exchanger 2, and the dust collector also reduces wear on the heat exchanger 2 caused by particulate matter in the flue gas, extending the service life of the device.

[0058] The utility model utilizes excess flue gas waste heat to heat nitrogen. No energy is required in the nitrogen heating process. The nitrogen heating temperature can be controlled by simply controlling the flue gas intake volume. By arranging an automatic regulating valve 18 at the flue gas inlet, the flue gas intake volume is automatically adjusted by obtaining the nitrogen temperature, thereby achieving the purpose of temperature stability. The utility model has a simple structure and does not require complicated operation.

[0059] A specific application of this application is:

[0060] Nitrogen is separated from the air separation tower 1 and enters the heat exchanger 2 through the first stop valve 9. After heat exchange, it is discharged through the second stop valve 10. After heating, the second pipeline 6 is insulated and directly enters the tin bath gas distribution chamber 3. Before entering the tin bath gas distribution chamber 3, a pressure gauge 12 is installed to check the nitrogen pressure. A bypass pipeline 7 and a bypass valve 11 are also required between the heat exchanger 2 to prevent the heat exchanger 2 from malfunctioning and causing nitrogen gas to stop supplying.

[0061] The flue gas from the kiln 4 is connected to the three-way pipe 8 after being treated by the flue gas. An automatic regulating valve 18 and a third stop valve 17 are set to control the flue gas flow by temperature to maintain a stable temperature, thereby achieving the purpose of nitrogen heating.

[0062] The utility model has at least the following advantages:

[0063] (1) Using excess flue gas heat to heat nitrogen is an environmentally friendly and economical energy utilization solution. In many industrial processes, the flue gas produced by combustion often carries a large amount of heat energy. If this heat energy is not utilized, it will not only cause energy waste, but also may cause thermal pollution to the environment. By designing a reasonable heat exchange system, we can effectively transfer the heat energy in these flue gases to nitrogen, so that the nitrogen that originally required additional energy to heat can use this low-cost heat energy, thereby realizing energy recycling.

[0064] (2) During the nitrogen heating process, no additional energy is required. The nitrogen heating temperature can be precisely controlled by controlling the flue gas intake. This heating method not only reduces production costs but also improves the controllability and stability of the heating process. By adjusting the flue gas intake, the nitrogen heating temperature can be controlled according to actual needs to meet the requirements of different processes.

[0065] (3) The device has a simple structural design and does not require complex operating procedures, which reduces maintenance costs and operational difficulty. This makes the device easier to install and use, while also improving its reliability and stability.

[0066] (4) To further improve the automation and temperature stability of the system, an automatic regulating valve for the flue gas inlet is also installed. This valve can automatically adjust the flue gas intake according to the real-time temperature of the nitrogen, thereby achieving precise temperature control. When the nitrogen temperature is lower than the set value, the valve will automatically increase the flue gas intake to improve heating efficiency; when the nitrogen temperature is higher than the set value, the valve will reduce the flue gas intake to prevent the temperature from being too high. In this way, we can ensure that the nitrogen temperature is always maintained within the set range, providing a stable heat source for the process.

[0067] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples. Based on the principles of the embodiments of the present invention, the technical features of the above embodiments or different embodiments may be combined, and there are many other variations of the different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention shall be included in the scope of protection of the embodiments of the present invention.

Claims

1. A nitrogen heating device utilizing waste heat from flue gas, characterized in that: include: An air separation tower (1), wherein the air separation tower (1) is provided with a first pipeline (5) for conveying nitrogen; A heat exchanger (2), the heat exchanger (2) being connected to the air separation tower (1) via the first pipeline (5), and the first pipeline (5) being provided with a first stop valve (9); a tin bath gas distribution chamber (3), the tin bath gas distribution chamber (3) being connected to the heat exchanger (2) via a second pipe (6), the second pipe (6) being provided with a second stop valve (10); The kiln (4) is connected to the heat exchanger (2) through a three-way pipe (8); the flue gas, after being treated, enters the heat exchanger (2) from the kiln (4) through the three-way pipe (8); and an automatic regulating valve is provided on the three-way pipe (8).

2. The nitrogen heating device using flue gas waste heat according to claim 1, characterized in that: The first pipeline (5) and the second pipeline (6) are connected via a bypass pipeline (7), and a bypass valve (11) is provided on the bypass pipeline (7).

3. The nitrogen heating device using flue gas waste heat according to claim 1, characterized in that: A pressure gauge (12) is provided on the second pipeline (6), and the pressure gauge (12) is used to measure the pressure of nitrogen.

4. The nitrogen heating device using flue gas waste heat according to claim 1, characterized in that: The three-way pipe (8) is also provided with a first temperature detection component (13), and the first temperature detection component (13) is used to measure the temperature of the flue gas before entering the heat exchanger (2).

5. The nitrogen heating device using flue gas waste heat according to claim 4, characterized in that: A second temperature detection component (14) is also provided on the second pipeline (6), and the second temperature detection component (14) is used to measure the temperature of the nitrogen after leaving the heat exchanger (2).

6. The nitrogen heating device using flue gas waste heat according to claim 1, characterized in that: The nitrogen heating device further comprises a desulfurization and denitrification system (15), the desulfurization and denitrification system (15) being connected to the kiln (4) via a three-way pipe (8), the desulfurization and denitrification system (15) being connected to the heat exchanger (2) via a third pipe (16), and a third stop valve (17) being provided on the third pipe (16).

7. The nitrogen heating device using flue gas waste heat according to claim 1, characterized in that: The heat exchanger (2) is a tubular heat exchanger (2).

8. The nitrogen heating device using flue gas waste heat according to claim 1, characterized in that: There are multiple heat exchangers (2).

9. The nitrogen heating device using flue gas waste heat according to claim 5, characterized in that: The first temperature detection component (13) and the second temperature detection component (14) are thermometers and / or thermocouples and / or temperature sensors.

10. The nitrogen heating device using flue gas waste heat according to claim 1, characterized in that: The nitrogen heating device further comprises an alarm component, wherein the alarm component is arranged on the first pipeline (5) and / or the second pipeline (6) and / or the third pipeline (16) and / or the bypass pipeline (7) and / or the three-way pipeline (8).

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