A method for igniting a furnace nitrogen seal

Abstract

The application belongs to the technical field of combustion, and provides a heating furnace nitrogen sealing ignition method, which comprises the following steps: confirming the ignition section based on an ignition instruction, confirming the closed state of the coal gas section valve and the burner valve of the gas inlet section, if the valve state confirmation result comprises that the coal gas section valve and the burner valve are both closed, closing the nitrogen gas blowing of the ignition section, opening the coal gas section valve of the ignition section to a first opening degree, keeping the nitrogen gas blowing of other gas inlet sections except the ignition section, then opening the burner valve, igniting the burner port corresponding to the ignition section, and if the ignition is successful, closing the nitrogen gas blowing of other gas inlet sections. By combining the nitrogen gas blowing and the ignition process, the degree of automation of ignition can be effectively improved, the ignition quality can be effectively improved, the risk of deflagration can be reduced, and the labor cost can be reduced. The method has the characteristics of ingenious idea, high degree of automation, wide adaptation range, and good risk control effect.

Description

Technical Field

[0001] This invention relates to the field of combustion technology, and in particular to a nitrogen-sealed ignition method for a heating furnace. Background Technology

[0002] Heating furnaces use gaseous fuels, heavy oil, or pulverized coal as fuel to provide heat for heating materials such as metals. They are indispensable equipment in the metallurgical industry. Among them, gas-fired heating furnaces use gases such as carbon monoxide as fuel. The gaseous fuel is transported through pipelines, and valves are installed on the pipelines to isolate the gaseous fuel. However, due to the gaseous nature of the fuel, even with multiple valves in the pipelines, it is still difficult to avoid gaseous fuel residue and leakage from the valves. This causes combustible gases such as carbon monoxide to accumulate in the pipelines and furnace. If the accumulation concentration is too high, deflagration will occur during ignition, and in severe cases, it may even cause an explosion.

[0003] Currently, when igniting a gas-fired heating furnace, in order to prevent the leakage and accumulation of combustible gas leading to deflagration, existing technologies often use inert gases such as nitrogen to purge the pipes or furnace. For example, in the patent document CN215491049U, a nitrogen purging device for a combustion furnace is disclosed. By setting a nitrogen purging pipe on the furnace body, nitrogen is used to purge the gas pipeline to prevent gas leakage and residue. Existing technologies have at least the following disadvantages: the nitrogen purging process is simple, no control logic has been proposed to combine it with the ignition process, it cannot effectively improve the ignition quality, and it relies on manual control, resulting in high labor costs and serious waste of resources. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a nitrogen-sealed ignition method for a heating furnace, which solves the problem that the nitrogen purging process in the existing ignition process is simple, and no control logic has been proposed to be integrated with the ignition process, relying on manual control.

[0005] To achieve the above and other related objectives, the present invention provides a nitrogen-sealed ignition method for a gas-fired heating furnace. The gas-fired heating furnace has multiple inlet sections, each inlet section being equipped with a gas section valve, a burner valve, and a nitrogen inlet. The nitrogen inlet is used to purge the inlet section with nitrogen before ignition. The ignition method includes:

[0006] Based on the ignition command, the ignition section is identified from multiple intake sections, and the closing status of the gas section valve and the burner valve in the intake section is confirmed to obtain the valve status confirmation result.

[0007] If the valve status confirmation result includes that both the gas section valve and the burner valve are closed, the nitrogen purging of the ignition section is stopped, and the gas section valve of the ignition section is opened to a first opening degree, which is less than the full opening degree of the gas section valve. Except for the ignition section, the other air intake sections are kept purged with nitrogen.

[0008] Open the burner valve to ignite the burner port corresponding to the ignition section, and determine the ignition status;

[0009] If the ignition status includes successful ignition, the nitrogen purging of the other intake sections except the ignition section is shut off.

[0010] Optionally, in each of the gas inlet sections, purging is performed from a distance of less than 80 cm from the gas section valve through the nitrogen inlet located downstream of the gas section valve; and venting is performed from a distance of less than 50 cm from the burner valve through the nitrogen exhaust port located between the nitrogen inlet and the burner valve.

[0011] The nitrogen purging includes the following steps:

[0012] When starting the nitrogen purging, first open the nitrogen exhaust port, and then open the nitrogen inlet port;

[0013] When shutting down the nitrogen purging, first close the nitrogen inlet, then close the nitrogen outlet.

[0014] Optionally, a first pressure sensor is provided upstream of the gas section valve, and a second pressure sensor is provided between the nitrogen inlet and the nitrogen outlet.

[0015] The nitrogen purging also includes the following steps:

[0016] The first air pressure is detected using the first air pressure sensor, and the second air pressure is detected using the second air pressure sensor.

[0017] Based on a preset pressure difference threshold, the relationship between the first gas pressure and the second gas pressure is determined. If the sum of the first gas pressure and the pressure difference threshold is less than the second gas pressure, the inlet pressure of the nitrogen inlet is reduced.

[0018] If the first gas pressure is greater than the second gas pressure, then increase the inlet pressure of the nitrogen inlet.

[0019] Optionally, each of the air inlet sections is further provided with a first gas concentration sensor, which is located between the gas section valve and the burner valve;

[0020] Before opening the burner valve and igniting the burner port corresponding to the ignition section, the ignition method further includes:

[0021] The carbon monoxide concentration in the ignition section is detected by the first gas concentration sensor to obtain a first concentration index, and the first concentration index is judged according to a preset first concentration threshold.

[0022] If the first concentration index is less than the first concentration threshold, then the burner valve remains closed.

[0023] Optionally, the gas-fired heating furnace is further provided with an air valve communicating with the furnace chamber, and a second gas concentration sensor is provided in the furnace chamber;

[0024] Before igniting the burner orifice corresponding to the ignition section, the ignition method further includes:

[0025] The second gas concentration sensor is used to detect the carbon monoxide concentration in the furnace to obtain a second concentration index.

[0026] Based on the comparison result between the second concentration index and the preset second concentration threshold, it is determined whether to perform a dilution operation on the furnace, the dilution operation including increasing the opening of the air valve;

[0027] If the second concentration index is greater than or equal to the second concentration threshold, then the dilution operation is performed;

[0028] If the first concentration index is greater than or equal to the first concentration threshold, and the second concentration index is less than the second concentration threshold, then the burner valve is opened.

[0029] Optionally, the first concentration threshold is 24 ppm.

[0030] Optionally, each of the intake sections is further provided with a vent valve, and after the nitrogen purging of the intake sections other than the ignition section is closed, the ignition method further includes:

[0031] Increase the opening degree of the gas section valve on the ignition section, and close all the vent valves.

[0032] Optionally, before igniting the burner orifice corresponding to the ignition section, the ignition method further includes:

[0033] Gas is sampled through the vent valve of the ignition section to obtain ignition sample gas;

[0034] An ignition test is performed on the ignition sample gas, and the ignition safety is determined based on the ignition test results.

[0035] If the ignition test results include deflagration, the ignition safety is determined to be unsafe, and a warning signal is issued.

[0036] Based on the warning signal, ignition is stopped before the next ignition command is obtained.

[0037] Optionally, the first opening is 30% of the full opening.

[0038] Optionally, the ignition state can be determined by the following steps:

[0039] The gas temperature at the burner is detected by a temperature sensor, and a temperature judgment is made according to a preset temperature threshold to obtain a temperature judgment result. The temperature sensor is installed on the gas-fired heater and is located near the burner.

[0040] If the temperature determination result includes that the gas temperature is greater than or equal to the temperature threshold, then the ignition state is confirmed as successful ignition.

[0041] In summary, the present invention has the following beneficial effects:

[0042] Based on the ignition command, the ignition section is identified from multiple intake sections, and the closing status of the gas section valve and burner valve in the intake section is confirmed to obtain the valve status confirmation result. If the valve status confirmation result includes that both the gas section valve and burner valve are closed, the nitrogen purging of the ignition section is stopped, the gas section valve of the ignition section is opened to the first opening degree, and nitrogen purging is maintained in other intake sections except for the ignition section. Then the burner valve is opened to ignite the burner port corresponding to the ignition section, and the ignition status is judged. If the ignition status includes successful ignition, the nitrogen purging of other intake sections except for the ignition section is stopped. This solves the problems of the existing technology where the nitrogen purging process is simple, and no control logic is proposed to be combined with the ignition process, which cannot effectively improve the ignition quality and relies on manual control, resulting in high labor costs and serious waste of resources. By combining nitrogen purging with the ignition process, the automation level of ignition can be effectively improved, the ignition quality can be effectively improved, the risk of deflagration can be reduced, and the labor cost can be reduced. It has the characteristics of ingenious idea, high degree of automation, wide range of application and good risk control effect. Attached Figure Description

[0043] Figure 1 A flowchart illustrating a nitrogen-sealing ignition method for a heating furnace is shown in an exemplary embodiment of this application;

[0044] Figure 2 for Figure 1 A flowchart of an exemplary implementation of nitrogen purging in step S110 of the illustrated embodiment;

[0045] Figure 3 for Figure 1A flowchart of an exemplary implementation of step S130 in the illustrated embodiment. Detailed Implementation

[0046] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0047] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "front," "rear," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0048] First, it should be noted that gas-fired heating furnaces use combustible gases such as carbon monoxide as fuel. Therefore, the furnace chamber is connected to a pipeline for transporting fuel. The air intake section and ignition section described in this application can be understood as part or all of the aforementioned pipelines. The naming convention is not a limitation on their structural features, but rather for the purpose of facilitating the understanding of the solution.

[0049] In one embodiment, please refer to Figure 1 This application exemplarily illustrates a nitrogen sealing ignition method for a heating furnace, applied to a gas-fired heating furnace. The gas-fired heating furnace is provided with multiple air inlet sections, each of which is provided with a gas section valve, a burner valve, and a nitrogen inlet. The nitrogen inlet is used to purge the air inlet section with nitrogen before ignition. Nitrogen purging here refers to introducing nitrogen through the nitrogen inlet so that the air inlet section is filled with nitrogen, thereby sealing the leakage path of the gas.

[0050] The above ignition method includes the following steps:

[0051] Step S110: Based on the ignition command, determine the ignition section from multiple intake sections, and confirm the closing status of the gas section valve and burner valve of the intake section to obtain the valve status confirmation result.

[0052] In this embodiment, the gaseous fuel is, for example, carbon monoxide.

[0053] For step S110, it is necessary to determine the ignition segment based on the ignition command. The ignition command here includes, but is not limited to, human operation actions such as touching a button, issuing a voice recognition signal, switching a physical switch or typing a control command, or readable electronic signals or analog signals generated based on the above operation actions or control requirements of other control scenarios. For example, in some embodiments, the operator issues an ignition command by touching the ignition button to start executing the steps described in this method.

[0054] It is important to understand that ignition of a gas-fired heating furnace begins from a single point. Ignition requires igniting the ignition material stored in the furnace chamber; that is, the ignition material is ignited first, and then the flame generated by the burning ignition material ignites the combustible gas introduced into the furnace chamber. To prevent the flame from accidentally extinguishing, causing a large accumulation of gas in the furnace chamber, and potentially leading to a combustion explosion upon re-ignition, in this embodiment, an ignition section needs to be determined from the air intake section. This ignition section supplies gaseous fuel to the ignition material in the furnace chamber first. After ignition is completed, gaseous fuel is supplied to other air intake sections outside the ignition section according to actual needs. The determination of the ignition section... The method can be based on the specific information included in the ignition command, or it can be based on the ignition command and determined according to the preset selection rules. For example, in some embodiments, the type of ignition command corresponds one-to-one with the location of the air intake section. Based on the receipt of different ignition commands, the air intake section at the corresponding location is determined as the ignition section. In other embodiments, the position of the igniter in the furnace has been preset, and the air intake section closest to the burner and the igniter has been selected as the ignition section. Based on the received ignition command, the air intake section is directly determined as the ignition section according to the preset rules.

[0055] In this embodiment, in addition to confirming the ignition section, it is also necessary to confirm the closed status of the gas section valve and burner valve of each air intake section and obtain the valve status confirmation result. The purpose of this step is to ensure that the gas section valve and burner valve are in the closed state before ignition, that is, the gaseous fuel is not discharged into the air intake section and furnace in large quantities, so as to prevent the valve from being opened by mistake, which would lead to a large leakage of gaseous fuel and cause an explosion.

[0056] In this embodiment, a nitrogen purging scheme is also specifically provided for the ignition method in this application. Specifically, in each gas inlet section, purging is performed from a distance of less than 80 cm from the gas section valve through a nitrogen inlet located downstream of the gas section valve; and venting is performed from a distance of less than 50 cm from the burner valve through a nitrogen exhaust port located between the nitrogen inlet and the burner valve.

[0057] Nitrogen purging includes the following steps:

[0058] When starting nitrogen purging, first open the nitrogen exhaust port, then open the nitrogen inlet port;

[0059] When shutting off nitrogen purging, first close the nitrogen inlet, then close the nitrogen outlet.

[0060] The above scheme can further ensure the quality of nitrogen purging, allowing nitrogen to fully cover the intake section to form a nitrogen seal, which is beneficial to further ensure ignition quality.

[0061] In this embodiment, a nitrogen purging control scheme is also specifically provided. Specifically, a first pressure sensor is installed upstream of the gas section valve, and a second pressure sensor is installed between the nitrogen inlet and the nitrogen outlet. Nitrogen purging is performed as follows: Figure 2 As shown, it also includes the following steps:

[0062] Step S210: The first air pressure is detected using the first air pressure sensor, and the second air pressure is detected using the second air pressure sensor;

[0063] Step S220: Based on the preset pressure difference threshold, determine the relationship between the first pressure and the second pressure. If the sum of the first pressure and the pressure difference threshold is less than the second pressure, reduce the intake pressure of the nitrogen inlet.

[0064] Step S230: If the first gas pressure is greater than the second gas pressure, then increase the inlet pressure of the nitrogen inlet.

[0065] For steps S210-S230, the inlet pressure of the nitrogen inlet can be provided by a gas pressure generating device or equipment commonly used in the field, such as a gas pump, and is not limited here. It should be understood that the purpose of this solution is to control the gas pressure during nitrogen purging. Before nitrogen purging, the gas pressure in the inlet section is the pressure of the gaseous fuel supplied. This can be detected by setting a first gas pressure sensor at the position where the gaseous fuel is full in the inlet section. If the nitrogen purging pressure is too high, it will lead to resource waste. At the same time, the nitrogen full in the inlet section may overflow from the gas section valve or burner valve, causing gas mixing. In addition, if the nitrogen exhaust port exhaust volume is insufficient, the exhaust in the inlet section will not be timely, or even the gas pressure will be too high, causing the components in the inlet section to be pressurized, damaging the valve, section body and other structures, and shortening the service life. If the nitrogen purging pressure is too low, the nitrogen sealing effect will be weakened or even unable to form an effective nitrogen seal. Therefore, reasonable control of the nitrogen purging pressure is beneficial to improving the nitrogen sealing effect, and thus to improving the ignition quality.

[0066] In this embodiment, a first pressure sensor located upstream of the gas section valve and a second pressure sensor located between the nitrogen inlet and the nitrogen outlet are used to detect the first pressure of the gaseous fuel in the intake section before purging, and the second pressure of the nitrogen inlet during nitrogen purging. These pressure sensors are then combined with a preset pressure difference threshold, which is the maximum pressure difference between the first and second pressures preset based on actual needs or experience. If the second pressure is greater than the first pressure and the difference exceeds the pressure difference threshold, it is determined to be a nitrogen inlet. If the intake pressure is too high, the intake pressure should be reduced accordingly. If the second pressure is lower than the first pressure, it is determined that the nitrogen inlet pressure is too low, and nitrogen purging will be obstructed when purging begins. Correspondingly, the nitrogen inlet pressure should be increased. For example, in some embodiments, the preset pressure difference threshold is 1 atmosphere. When the measured second pressure is greater than the first pressure, and the second pressure exceeds the first pressure by 1.2 atmospheres, it is determined that the second pressure is too high. At this time, the intake pressure is reduced until the difference between the second pressure and the first pressure is no greater than 1 atmosphere.

[0067] The above steps can further improve the nitrogen purging effect in the nitrogen sealing ignition method for a heating furnace of this application, which is conducive to further improving the safety during ignition.

[0068] Step S120: If the valve status confirmation result includes both the gas section valve and the burner valve being closed, the nitrogen purging of the ignition section is stopped, and the gas section valve of the ignition section is opened to the first opening degree, which is less than the full opening degree of the gas section valve. Nitrogen purging is maintained in other air intake sections except the ignition section.

[0069] For step S120, if it is confirmed that the valves including the gas section valve and the burner valve are all closed, it means that the nitrogen purging in each air intake section has been carried out normally and there is no situation of valves being opened by mistake. At this time, the nitrogen purging of the ignition section is closed and the gas section valve of the ignition section is opened to the first opening degree. In this embodiment, the first opening degree is 30% of the full opening degree. The purpose is to control the carbon monoxide concentration during ignition, which is conducive to further avoiding deflagration. After the gas section valve is opened, the nitrogen purging of other air intake sections, except for the ignition section, continues to be maintained to prevent carbon monoxide from other air intake sections from leaking into the furnace through other air intake sections.

[0070] It is understandable that the process of removing and plugging blind flanges in the prior art is not a necessary technical feature for the implementation of this solution and therefore is not limited thereto. In actual operation, the removal and plugging of blind flanges can be carried out together with this solution as needed. For example, in some implementations, before opening the gas section valve, the blind flange is removed according to the process specifications and then the gas section valve is opened. This does not affect the implementation of this solution and should still be included within the scope of implementation of this solution.

[0071] Step S130: Open the burner valve, ignite the burner port corresponding to the ignition section, and determine the ignition status.

[0072] In step S130, after the burner valve is opened, the gaseous fuel in the ignition section enters the burner through the burner valve and then enters the furnace. Under normal circumstances, it will be ignited by the igniter near the burner. At this time, it is necessary to judge the ignition status.

[0073] In this embodiment, the ignition status is determined through the following steps:

[0074] The gas temperature at the burner is detected by a temperature sensor, and the temperature is judged according to a preset temperature threshold to obtain the temperature judgment result. The temperature sensor is set on the gas-fired heater and close to the burner.

[0075] If the temperature determination result includes a gas temperature greater than or equal to the temperature threshold, then the ignition status is confirmed as successful ignition.

[0076] Regarding the above steps, it is understandable that there is a significant temperature difference in the furnace before and after ignition. By placing a temperature sensor near the burner in the ignition section of the furnace, the temperature change at the burner can be effectively detected. When the gas temperature is higher than the preset temperature threshold, it indicates that combustion has started at the burner, and the ignition status can be confirmed as successful ignition. In other cases, such as when the gas temperature detected by the temperature sensor after ignition remains below the temperature threshold, it indicates that ignition has failed, and the ignition status can be confirmed as failed ignition.

[0077] In this embodiment, to ensure the normal operation of the ignition process, a scheme is also provided to judge the nitrogen purging effect based on the gas concentration and then control the ignition process. Specifically, each air inlet section is also equipped with a first gas concentration sensor, which is located between the gas section valve and the burner valve. The gas-fired heating furnace is also equipped with an air valve connected to the furnace chamber, and a second gas concentration sensor is installed in the furnace chamber.

[0078] Before opening the burner valve and igniting the corresponding burner port in the ignition section, such as Figure 3 As shown, the ignition method also includes the following steps:

[0079] Step S310: The carbon monoxide concentration in the ignition section is detected by the first gas concentration sensor to obtain the first concentration index.

[0080] Step S320: Determine the first concentration index based on the preset first concentration threshold;

[0081] Step S330: If the first concentration index is less than the first concentration threshold, then keep the burner valve closed;

[0082] Step S340: The carbon monoxide concentration in the furnace is detected by the second gas concentration sensor to obtain the second concentration index;

[0083] Step S350: Based on the comparison result between the second concentration index and the preset second concentration threshold, determine whether to perform a dilution operation on the furnace. The dilution operation includes increasing the opening of the air valve.

[0084] Step S360: If the second concentration index is greater than or equal to the second concentration threshold, then perform a dilution operation;

[0085] Step S370: If the first concentration index is greater than or equal to the first concentration threshold and the second concentration index is less than the second concentration threshold, then the burner valve is opened.

[0086] For steps S310-S330, the carbon monoxide concentration in the ignition section is detected. At this time, since nitrogen purging is turned off and the gas section valve is opened, the carbon monoxide concentration begins to rise. However, since the carbon monoxide concentration needs to reach a certain value, i.e., the first concentration threshold, for normal ignition, otherwise, problems such as failure to ignite or immediate extinguishing after ignition will occur, it is necessary to judge based on the preset first concentration threshold and the obtained first concentration index. If the first concentration index is less than the preset first concentration threshold, it means that the carbon monoxide concentration in the ignition section is not yet sufficient for normal ignition, and it is necessary to wait for carbon monoxide to continue to accumulate to increase the concentration. Therefore, ignition is delayed, and the burner valve is kept closed. It can be understood that if the detected first concentration index is greater than or equal to the first concentration threshold, it means that the carbon monoxide concentration in the ignition section is sufficient for normal ignition, and it has no impact on subsequent steps. Other steps can then be continued.

[0087] In some other embodiments, steps S310-S330 can also be implemented independently of subsequent steps S340-S370. As a concentration determination scheme for gaseous fuel, it helps to ensure that the carbon monoxide concentration meets the combustion standards during ignition, which helps to further improve the ignition quality.

[0088] For steps S340-S370, based on the detection of the combustible gas concentration in the ignition section (i.e., the first concentration index), the carbon monoxide concentration in the furnace is further detected to obtain the second concentration index. The second concentration index reflects the carbon monoxide concentration in the furnace. Since the burner valve is not yet open, the source of the second concentration index at this time is residual and leaked carbon monoxide. If its concentration exceeds a certain value, i.e., the second concentration threshold, then when the gaseous fuel in the ignition section enters the furnace, the carbon monoxide it contains will mix with the carbon monoxide in the furnace, resulting in a high concentration of mixed carbon monoxide and a risk of deflagration. Therefore, it is necessary to control... The carbon monoxide concentration in the furnace is also known as the second concentration index. It must be kept below the second concentration threshold. If the second concentration index is greater than or equal to the second concentration threshold, a dilution operation is performed. The dilution operation includes increasing the opening of the air valve to introduce air from outside the furnace, thereby reducing the original gas concentration in the furnace and thus reducing the carbon monoxide concentration. If the first concentration index is greater than or equal to the first concentration threshold and the second concentration index is less than the second concentration threshold, it means that the carbon monoxide concentration in the ignition section can meet the requirements for normal ignition, and the carbon monoxide that has accumulated in the furnace will not pose a danger to ignition. In this case, the burner valve can be opened to allow normal ignition.

[0089] In this embodiment, the first concentration threshold is set to 24 ppm (parts per million), which is beneficial to further improve the ignition quality. The second concentration threshold can be set differently depending on the structural differences, volume, and experience of the furnace, and is not limited here.

[0090] As mentioned above, S310-S370 further ensure the safety of ignition.

[0091] Step S140: If the ignition status includes successful ignition, shut off the nitrogen purging of other intake sections except the ignition section.

[0092] For step S140, after the burner in the ignition section is successfully ignited, normal combustion has begun in the furnace. At this time, nitrogen purging of other air intake sections except the ignition section is turned off. It is worth noting that the reason for deflagration in the combustion furnace is that combustible gas has already accumulated in the furnace during ignition, and the concentration of the accumulated combustible gas has exceeded the concentration threshold for safe combustion. Once the furnace has been ignited and normal combustion has begun, combustible gas entering through the air intake section will no longer cause deflagration. Therefore, after ignition, except for the ignition section where nitrogen purging has been turned off and coal gas has been introduced, other air intake sections do not need to be purged with nitrogen to reduce the energy waste caused by meaningless nitrogen purging.

[0093] In this embodiment, each intake section is also equipped with a vent valve. After closing the nitrogen purging of the intake sections other than the ignition section, the above ignition method further includes the following steps:

[0094] Increase the opening of the gas section valve in the ignition section and close all vent valves.

[0095] In the above steps, the venting valve can be understood as a valve installed on the air intake section. It can be used to assist in regulating the pressure in the air intake section and the combustion furnace, or to release the gas in the air intake section. After ignition, the combustion furnace enters the normal combustion state and can discharge flue gas through the exhaust port. Therefore, the venting valve can be completely closed. At the same time, according to the fuel supply demand during combustion, the opening of the gas section valve can be increased to ensure the fuel supply during combustion.

[0096] In this embodiment, a scheme for judging and warning of the safety of gaseous fuel in the ignition section before ignition is also provided. Specifically, before igniting the burner port corresponding to the ignition section, the ignition method further includes:

[0097] Gas samples are taken through the vent valve of the ignition section to obtain ignition sample gas;

[0098] Ignition tests are conducted on the ignition sampled gas, and the ignition safety is determined based on the ignition test results.

[0099] If the ignition test results include deflagration, the ignition safety is deemed unsafe, and a warning signal is issued.

[0100] Based on the warning signal, ignition is stopped before the next ignition command is received.

[0101] For the above steps, before ignition, in conjunction with the function of the vent valve, a gas sample is taken from the gaseous fuel in the ignition section to obtain the ignition sample gas, and an ignition test is performed on it. It should be understood that the ignition test here is a test used in the field of combustion to determine the ignition safety of combustible gases. Its principle is to collect combustible gas and ignite it. Based on the phenomenon during ignition, it is determined whether the concentration of combustibles in the combustible gas meets the safe ignition range. If deflagration occurs, it indicates that there is a defect in the concentration of combustible gas in the collected gaseous fuel, and there is a risk of deflagration. At this time, the ignition safety is determined to be unsafe, and a warning signal is issued. Based on the warning signal, the current ignition step is controlled to end until the on-site personnel have checked and proceeded to the next ignition. As described above, this judgment and warning scheme helps to further ensure the safety of ignition.

[0102] In summary, in the nitrogen-sealed ignition method for a heating furnace provided in this application, based on the ignition command, the ignition section is identified from multiple intake sections, and the closing status of the gas section valve and burner valve in the intake section is confirmed to obtain the valve status confirmation result. If the valve status confirmation result includes both the gas section valve and the burner valve being closed, nitrogen purging of the ignition section is stopped, the gas section valve of the ignition section is opened to the first opening degree, and nitrogen purging is maintained in other intake sections except for the ignition section. Then, the burner valve is opened to ignite the burner port corresponding to the ignition section, and the ignition status is judged. If the ignition status is... The process includes successful ignition and shutting off nitrogen purging in all intake sections except the ignition stage. This solves the problems of existing technologies where the nitrogen purging process is simplistic, lacks integrated control logic, and fails to effectively improve ignition quality. Furthermore, it relies on manual control, leading to high labor costs and significant resource waste. By integrating nitrogen purging with the ignition process, the system effectively enhances the automation of ignition, improves ignition quality, reduces the risk of deflagration, and lowers labor costs. It features ingenious design, high automation, wide applicability, and excellent risk control.

[0103] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for nitrogen-sealed ignition of a heating furnace, characterized in that, This invention is applied to a gas-fired heating furnace, which has multiple air inlet sections. Each air inlet section is equipped with a gas section valve, a burner valve, and a nitrogen inlet. The nitrogen inlet is used to purge the air inlet section with nitrogen before ignition. The ignition method includes: Based on the ignition command, the ignition section is determined from multiple intake sections, and the closing status of the gas section valve and the burner valve in the intake section is confirmed to obtain the valve status confirmation result. If the valve status confirmation result includes that both the gas section valve and the burner valve are closed, the nitrogen purging of the ignition section is stopped, and the gas section valve of the ignition section is opened to a first opening degree, which is less than the full opening degree of the gas section valve. Except for the ignition section, the other air intake sections are kept purged with nitrogen. Open the burner valve to ignite the burner port corresponding to the ignition section, and determine the ignition status; If the ignition status includes successful ignition, the nitrogen purging of the other intake sections except the ignition section is shut off.

2. The nitrogen-sealed ignition method for a heating furnace according to claim 1, characterized in that, In each of the gas inlet sections, purging is performed from a distance of less than 80 cm from the gas section valve through the nitrogen inlet located downstream of the gas section valve; and venting is performed from a distance of less than 50 cm from the burner valve through the nitrogen exhaust port located between the nitrogen inlet and the burner valve. The nitrogen purging includes the following steps: When starting the nitrogen purging, first open the nitrogen exhaust port, and then open the nitrogen inlet port; When shutting down the nitrogen purging, first close the nitrogen inlet, then close the nitrogen outlet.

3. The nitrogen-sealed ignition method for a heating furnace according to claim 2, characterized in that, A first pressure sensor is installed upstream of the gas section valve, and a second pressure sensor is installed between the nitrogen inlet and the nitrogen outlet. The nitrogen purging also includes the following steps: The first air pressure is detected using the first air pressure sensor, and the second air pressure is detected using the second air pressure sensor. Based on a preset pressure difference threshold, the relationship between the first gas pressure and the second gas pressure is determined. If the sum of the first gas pressure and the pressure difference threshold is less than the second gas pressure, the inlet pressure of the nitrogen inlet is reduced. If the first gas pressure is greater than the second gas pressure, then increase the inlet pressure of the nitrogen inlet.

4. The nitrogen-sealed ignition method for a heating furnace according to claim 1, characterized in that, Each of the air inlet sections is also provided with a first gas concentration sensor, which is located between the gas section valve and the burner valve. Before opening the burner valve and igniting the burner port corresponding to the ignition section, the ignition method further includes: The carbon monoxide concentration in the ignition section is detected by the first gas concentration sensor, and a first concentration index is obtained. The first concentration index is judged according to a preset first concentration threshold. If the first concentration index is less than the first concentration threshold, then the burner valve remains closed.

5. The nitrogen-sealed ignition method for a heating furnace according to claim 4, characterized in that, The gas-fired heating furnace is also equipped with an air valve that communicates with the furnace chamber, and a second gas concentration sensor is installed in the furnace chamber. Before igniting the burner orifice corresponding to the ignition section, the ignition method further includes: The second gas concentration sensor is used to detect the carbon monoxide concentration in the furnace to obtain a second concentration index. Based on the comparison result between the second concentration index and the preset second concentration threshold, it is determined whether to perform a dilution operation on the furnace, the dilution operation including increasing the opening of the air valve; If the second concentration index is greater than or equal to the second concentration threshold, then the dilution operation is performed; If the first concentration index is greater than or equal to the first concentration threshold, and the second concentration index is less than the second concentration threshold, then the burner valve is opened.

6. The nitrogen-sealed ignition method for a heating furnace according to claim 4, characterized in that: The first concentration threshold is 24 ppm.

7. The nitrogen-sealed ignition method for a heating furnace according to claim 1, characterized in that, Each of the intake sections is further provided with a vent valve. After the nitrogen purging of the intake sections other than the ignition section is closed, the ignition method further includes: Increase the opening degree of the gas section valve on the ignition section, and close all the vent valves.

8. The nitrogen-sealed ignition method for a heating furnace according to claim 7, characterized in that, Before igniting the burner orifice corresponding to the ignition section, the ignition method further includes: Gas is sampled through the vent valve of the ignition section to obtain ignition sample gas; An ignition test is performed on the ignition sample gas, and the ignition safety is determined based on the ignition test results. If the ignition test results include deflagration, the ignition safety is determined to be unsafe, and a warning signal is issued. Based on the warning signal, ignition is stopped before the next ignition command is obtained.

9. The nitrogen-sealed ignition method for a heating furnace according to claim 1, characterized in that: The first opening is 30% of the full opening.

10. A method for nitrogen sealing and ignition of a heating furnace according to claim 1, characterized in that, The ignition state is determined by the following steps: The gas temperature at the burner is detected by a temperature sensor, and a temperature judgment is made according to a preset temperature threshold to obtain a temperature judgment result. The temperature sensor is installed on the gas-fired heater and is located near the burner. If the temperature determination result includes that the gas temperature is greater than or equal to the temperature threshold, then the ignition state is confirmed as successful ignition.

Images