Natural gas boiler debugging operation method and natural gas boiler

Abstract

The invention belongs to the technical field of industrial boilers, and discloses a natural gas boiler debugging operation method and a natural gas boiler. The method comprises the steps that fuel gas and air are conveyed to a combustor, the combustor operates to a load point after being ignited, the primary fuel gas ratio is controlled to be within a first range, the secondary fuel gas ratio is controlled to be within a second range, and meanwhile the FGR smoke suction amount is controlled to be within a third range; the combustion state in the boiler is obtained, and the primary fuel gas proportion and the secondary fuel gas proportion are adjusted; the oxygen content of the discharged flue gas is obtained to adjust the total air inlet amount during operation of the boiler; the amount of nitric oxide (NOx) of discharged flue gas is obtained, and the FGR smoke suction amount is adjusted; and when the combustion state, the oxygen content of the discharged flue gas and the nitrogen oxide (NOx) amount of the discharged flue gas all meet the requirements, running to the next load point, and repeating the process for debugging. Therefore, in the operation process of the natural gas boiler, all parameters can be matched with one another, dynamic adjustment is achieved, and the performance of the natural gas boiler is comprehensively improved.

Description

Technical Field

[0001] This invention relates to the technical field of industrial boilers, and more particularly to a method for commissioning and operating a natural gas boiler and the natural gas boiler itself. Background Technology

[0002] As an important energy conversion device, the energy efficiency and pollutant emissions of natural gas boilers are directly related to energy utilization efficiency and environmental protection effectiveness. Achieving efficient and stable combustion in boilers is the core link to improving energy efficiency and reducing emissions. The boiler combustion process is affected by multiple parameters, including the stability of natural gas supply, the accuracy of air supply, the dynamic changes in flue gas oxygen content, and the structural characteristics of the flame stabilizer. Fluctuations in any parameter may lead to problems such as incomplete combustion, decreased thermal efficiency, or increased pollutant generation.

[0003] In existing technologies, boiler combustion commissioning typically employs a point-by-point commissioning method. Commissioning personnel must independently set parameters such as gas pressure and air volume for each load point, and verify the adjustment effect by monitoring indicators such as flue gas oxygen content and nitrogen oxide (NOx) emissions, ultimately determining the optimal parameter combination for that load point. This step-by-step commissioning method is theoretically systematic, covering the full load operating range of the boiler and providing data support for parameter control under different operating conditions; therefore, it is widely used in the industry.

[0004] However, because the parameter adjustments at each load point are independent of each other and there is a lack of consideration for the dynamic coupling relationship between parameters, the matching of parameters such as gas pressure, air volume and flue gas oxygen content in the commissioning results is insufficient. This directly causes combustion fluctuations in the boiler when switching between different loads, making it difficult to maintain a low nitrogen emission level and increasing energy consumption due to reduced combustion efficiency. Ultimately, this restricts the realization of the comprehensive benefits of boiler energy saving and pollution reduction. Summary of the Invention

[0005] The purpose of this invention is to provide a method for commissioning and operating a natural gas boiler, as well as a natural gas boiler, to solve the problem that the matching between various parameters in the operation of existing natural gas boilers is insufficient, making it difficult to effectively balance energy saving and pollution reduction.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for commissioning and operating a natural gas boiler, comprising: After supplying gas and air to the burner and igniting it, the system operates to the load point, controlling the primary gas ratio within the first range and the secondary gas ratio within the second range, while simultaneously controlling the FGR smoke extraction gas volume within the third range. The combustion state inside the boiler is obtained, and the primary fuel gas ratio and the secondary fuel gas ratio are adjusted according to the combustion state. Obtain the oxygen content of the emitted flue gas, and adjust the total air intake of the boiler during operation based on the oxygen content; The amount of nitrogen oxides (NOx) in the emitted flue gas is obtained, and the amount of flue gas drawn by the FGR is adjusted according to the amount of nitrogen oxides (NOx); When the combustion state, the oxygen content of the flue gas, and the nitrogen oxide (NOx) content of the flue gas all meet the requirements, the system will run to the next load point and repeat the above process for debugging.

[0007] Optionally, obtaining the combustion state inside the boiler and adjusting the primary fuel gas ratio and secondary fuel gas ratio according to the combustion state specifically includes: The stability of the flame in the combustion zone is obtained, and the primary fuel gas ratio is adjusted according to the stability of the flame in the combustion zone to ensure that the primary fuel gas ratio is greater than 85%.

[0008] Optionally, obtaining the combustion state inside the boiler and adjusting the primary fuel gas ratio and secondary fuel gas ratio according to the combustion state specifically includes: The boiler furnace temperature is obtained. When the furnace temperature is less than a first threshold, the secondary fuel gas ratio is increased. When the furnace temperature is greater than a second threshold, the secondary fuel gas ratio is decreased. When the furnace temperature is between the first threshold and the second threshold, the secondary fuel gas ratio is maintained. Wherein, the second threshold is greater than the first threshold.

[0009] Optionally, the adjustment of the total air intake volume specifically includes: Adjust the fan frequency or adjust the connectivity area of ​​the air inlet channel.

[0010] Optionally, the step of obtaining the amount of nitrogen oxides (NOx) in the emitted flue gas and adjusting the amount of flue gas drawn by the FGR according to the amount of nitrogen oxides (NOx) specifically includes: When the amount of nitrogen oxides (NOx) in the emitted flue gas is greater than a first preset concentration, the amount of flue gas drawn by the FGR is increased.

[0011] Optionally, after the boiler is ignited and reaches the first load point, the natural gas supply is controlled to a first supply threshold, and after each subsequent load point, the natural gas supply is increased by a second supply threshold.

[0012] Optionally, the amount of smoke drawn by the FGR is controlled to be greater than 5% and less than 15% of the total smoke volume.

[0013] Optionally, the total air supply volume is controlled to be at least 10 times the natural gas supply volume.

[0014] In a second aspect, the present invention provides a natural gas boiler that applies the commissioning and operation method for a natural gas boiler as described in any one of the first aspects, comprising: Furnace body; The burner is installed in the furnace body; A gas pipeline assembly is connected to the burner to deliver gas into the burner in a ratio of primary gas blending and secondary gas blending. The air inlet pipe is connected to the burner at one end and is equipped with an air supply device at the other end for supplying air and adjusting the total air volume. An exhaust pipe is provided at the exhaust port of the furnace body to discharge flue gas. The FGR pipe assembly has one end connected to the exhaust pipe and the other end connected to the air inlet pipe to circulate and guide part of the flue gas into the air inlet pipe. The detection module is used to detect the total air intake volume, primary gas ratio, secondary gas ratio, FGR smoke extraction volume, oxygen content of exhaust gas, and nitrogen oxide (NOx) content. The control module is communicatively connected to the detection module, the gas pipe assembly, the air supply device, and the FGR pipe assembly, respectively.

[0015] Optionally, the air supply device includes: The variable frequency fan is embedded in the air inlet duct; An air inlet baffle is movably connected to the air inlet of the air inlet pipe to adjust the connectivity area of ​​the air inlet.

[0016] The beneficial effects of this invention are: Firstly, using the above method, once the boiler reaches its first load point, the primary gas ratio is controlled within the first range, the secondary gas ratio within the second range, and the FGR (Fuel Gas Refrigerant) intake gas volume within the third range. Then, based on the combustion state, oxygen content, and nitrogen oxide (NOx) content, the above parameters and total intake air volume are dynamically adjusted until the combustion state, oxygen content, and NOx content of the exhaust gas all meet the requirements at that load point. This completes the commissioning of one load point. The above method is then repeated at the next load point until all load points are commissioned. Therefore, during the subsequent operation of the natural gas boiler, the various parameters can be matched and dynamically adjusted. This not only ensures that the combustion state inside the boiler remains stable but also ensures that the oxygen content and NOx content of the exhaust gas meet the requirements. As a result, the boiler can not only guarantee stable combustion and achieve energy saving during operation but also reduce pollutants in the exhaust gas, achieving pollution reduction. This balances both energy saving and pollution reduction, comprehensively improving the performance of the natural gas boiler.

[0017] Secondly, during operation, the natural gas boiler receives gas from the gas pipeline group at primary and secondary gas ratios. Simultaneously, the air supply assembly delivers air to the burner through the air inlet pipe. After the gas and air mix, they are ignited and fully combusted within the furnace. The flue gas generated during combustion is discharged through the exhaust pipe, and a portion of the discharged flue gas is recycled back to the air inlet pipe through the FGR pipeline group. The detection module monitors the total air intake, primary gas ratio, secondary gas ratio, FGR smoke extraction volume, oxygen content, and nitrogen oxide (NOx) content of the exhaust gas in real time, and feeds the detection results back to the control module. The control module adjusts the natural gas boiler using the aforementioned commissioning and operation methods, ensuring that each load point of the natural gas boiler meets the requirements for energy saving and pollution reduction, thereby effectively improving the overall performance of the natural gas boiler. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of a natural gas boiler commissioning and operation method according to an embodiment of the present invention; Figure 2 This is a system flowchart of a natural gas boiler commissioning and operation method according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the composition of a natural gas boiler according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a natural gas boiler according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a variable frequency fan for a natural gas boiler according to an embodiment of the present invention.

[0019] In the picture: 1. Furnace body; 2. Burner; 3. Air inlet pipe; 4. Exhaust pipe; 41. First economizer; 42. Second economizer; 5. FGR pipe assembly; 51. Movable baffle; 6. Chimney; 7. Variable frequency fan; 71. Electric baffle; 72. Exhaust pipe; 8. Air inlet baffle. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] like Figures 1 to 5 As shown, the present invention provides a method for commissioning and operating a natural gas boiler, and a natural gas boiler.

[0025] Reference Figure 1 The commissioning and operation method of this natural gas boiler includes: Step S1: After supplying gas and air to the burner and igniting it, the burner is operated to the load point. The primary gas ratio is controlled within the first range, and the secondary gas ratio is controlled within the second range. At the same time, the amount of gas drawn by the FGR is controlled within the third range.

[0026] A natural gas boiler is a heat energy conversion device that uses natural gas as fuel to heat boiler water and generate steam or hot water. It belongs to the category of gas-fired boilers, and the fuel gas used in this invention is all natural gas. The load point refers to the boiler's capacity to produce steam or hot water per unit time during operation, usually expressed as rated evaporation capacity (t / h) or thermal power (MW). During operation, natural gas boilers need to be adjusted according to external demand to sequentially reach the corresponding load point to ensure safe, stable, and efficient operation.

[0027] When a natural gas boiler (hereinafter referred to as the boiler) is in operation, natural gas is introduced into the burner through dual gas pipes. The gas ratio in each gas pipe is different. The gas ratio refers to the volume or mass ratio of each component after mixing two or more different types and properties of gas during combustion. It can optimize the gas composition and achieve efficient, high-temperature, and environmentally friendly combustion. The FGR (Flue Gas Recirculation) intake gas volume refers to the amount of flue gas emitted during boiler operation that is reintroduced into the burner, mixed with air, and re-combusted. It can effectively suppress the production of nitrogen oxides. When the boiler reaches its load point, the primary gas ratio, secondary gas ratio, and FGR intake gas volume all need to be within a certain range and dynamically adjusted in real time to ensure that the energy saving and pollution reduction of the natural gas boiler meet the requirements.

[0028] Step S2: Obtain the combustion status inside the boiler and adjust the primary gas ratio and secondary gas ratio according to the combustion status.

[0029] The combustion state inside the boiler includes furnace temperature, flame stability, and other aspects. The adjustment of the primary gas ratio and the secondary gas ratio can directly affect the combustion state inside the boiler. Once the actual combustion state inside the boiler is obtained, the primary gas ratio and the secondary gas ratio can be dynamically adjusted according to the needs of the corresponding load point so that the actual combustion state can meet the corresponding requirements.

[0030] Step S3: Obtain the oxygen content of the emitted flue gas and adjust the total air intake during boiler operation according to the oxygen content.

[0031] During operation, the boiler continuously emits flue gas. The oxygen content can be obtained by detecting the flue gas. The excess air coefficient during boiler operation must meet the requirements of the "Technical Conditions for Industrial Boilers". When the actual oxygen content does not meet the requirements, such as when the oxygen content deviates from the range of 5% to 6%, it is necessary to adjust the air intake, that is, the total air intake of the boiler, so as to adjust the amount of oxygen entering the boiler and thus regulate the oxygen content in the flue gas.

[0032] Step S4: Obtain the amount of nitrogen oxides (NOx) in the emitted flue gas and adjust the amount of flue gas drawn by the FGR according to the amount of nitrogen oxides (NOx).

[0033] The amount of nitrogen oxides (NOx) can be obtained by detecting the NOx content in flue gas. According to environmental protection requirements, the amount of nitrogen oxides (NOx) needs to be kept below a specified concentration. By using an air purifier (FGR) to draw in some flue gas and recirculate it, the amount of nitrogen oxides (NOx) in the flue gas emissions can be effectively reduced. Based on the actual detection results, the amount of flue gas drawn in by the FGR can be adjusted in real time, so that the amount of nitrogen oxides (NOx) in the emitted flue gas can always be kept within the corresponding requirements.

[0034] Step S5: When the combustion state, the oxygen content of the flue gas, and the amount of nitrogen oxides (NOx) in the flue gas all meet the requirements, run to the next load point and repeat the above process for debugging.

[0035] After the boiler reaches the first load point, the primary gas ratio, secondary gas ratio, total Jinfeng circuit, and FGR smoke extraction volume are dynamically adjusted according to the above process. When the combustion state, the oxygen content of the flue gas, and the amount of nitrogen oxides (NOx) in the flue gas meet the requirements, the adjusted parameters are recorded, and the boiler is run to the second load point for further adjustment until all load point parameters are recorded. In subsequent boiler operation, each load point only needs to be dynamically adjusted according to the above parameters.

[0036] Through steps S1 to S5 above, after the boiler reaches the first load point, the primary gas ratio is controlled within the first range, the secondary gas ratio within the second range, and the FGR flue gas volume within the third range. Then, the above parameters and total air intake are dynamically adjusted according to the combustion state, oxygen content, and nitrogen oxide (NOx) content until the combustion state, oxygen content, and NOx content of the flue gas all meet the requirements at that load point. This completes the commissioning of one load point. The above method is then repeated at the next load point until all load points are commissioned. Therefore, during the subsequent operation of the natural gas boiler, the various parameters can be matched with each other and dynamically adjusted. This not only ensures that the combustion state in the boiler remains stable, but also ensures that the oxygen content and NOx content of the flue gas meet the requirements. As a result, the boiler can not only ensure stable combustion and achieve energy saving during operation, but also reduce pollutants in the exhaust gas and achieve pollution reduction. This balances energy saving and pollution reduction, comprehensively improving the performance of the natural gas boiler.

[0037] Reference Figure 2 Optionally, step S2 above specifically includes: Obtain the stability of the flame in the combustion zone, adjust the primary fuel mixture ratio according to the stability of the flame in the combustion zone, and ensure that the primary fuel mixture ratio is greater than 85%.

[0038] The primary gas ratio can be controlled by an electric butterfly valve. The first range is between 85% and 95%, which ensures that the primary gas ratio is greater than 85%, ensuring sufficient fuel in the combustion zone, and that the flame remains stable, reducing the possibility of flameout or even flameout due to insufficient fuel.

[0039] Optionally, step S2 above specifically includes: The boiler furnace temperature is obtained. When the furnace temperature is less than a first threshold, the secondary gas ratio is increased. When the furnace temperature is greater than a second threshold, the secondary gas ratio is decreased. When the furnace temperature is between the first and second thresholds, the secondary gas ratio is maintained. The second threshold is greater than the first threshold.

[0040] The secondary fuel gas ratio can also be controlled by an electric butterfly valve, with a second range of 5%-15%. The combination of primary and secondary fuel gas ratios enables low-NOx combustion. When the furnace temperature is below the first threshold, the flame in the surface furnace is weak. Increasing the secondary fuel gas ratio increases fuel production and strengthens the flame, causing the furnace temperature to rise rapidly. Conversely, when the furnace temperature is above the second threshold, the surface furnace temperature is too high. In this case, the secondary fuel gas ratio can be appropriately reduced to weaken the flame and lower the furnace temperature. Ultimately, the furnace temperature is stabilized between the first and second thresholds, while preventing an increase in the concentration of nitrogen oxides in the flue gas. In this embodiment, the first threshold is 1500℃, and the second threshold is 1600℃.

[0041] Optionally, adjusting the total air intake volume specifically includes: Adjust the fan frequency or adjust the connectivity area of ​​the air inlet channel.

[0042] Specifically, air delivery is achieved using a variable frequency fan. By adjusting the fan frequency, the fan power can be changed, thereby regulating the total air intake. Baffles or other structures can also be installed at the air delivery duct to alter the connection area between the duct and the outside, thus changing the total air intake. In this embodiment, the fan frequency conversion can only be adjusted within the 50%-100% load range. When the load is less than 50%, the total air intake is further controlled by adjusting the connection area of ​​the air intake channel.

[0043] Optionally, step S4 above specifically includes: When the amount of nitrogen oxides (NOx) in the flue gas exceeds the first preset concentration, the amount of flue gas drawn in by the FGR is increased.

[0044] Specifically, the first preset concentration can be set to 30 mg / Nm³. 3 When the amount of nitrogen oxides (NOx) in the flue gas exceeds the first preset concentration, the amount of flue gas drawn in by the FGR is increased, so that more flue gas is circulated into the boiler, thereby reducing the amount of nitrogen oxides (NOx) in the flue gas.

[0045] Optionally, the amount of smoke drawn by the FGR is controlled to be greater than 5% and less than 15% of the total smoke volume.

[0046] Specifically, the third range is 5% to 15% of the total flue gas volume. Controlling the FGR to draw in more than 5% of the total flue gas volume ensures that some of the emitted flue gas can be circulated back into the furnace, thereby effectively diluting the oxygen concentration and reducing the generation of nitrogen oxides. If the FGR to draw in less than 15% of the total flue gas volume, it can be controlled at around 10%, thereby avoiding the situation where the flue gas circulation flow is too large, causing the furnace temperature to drop rapidly and interfering with combustion.

[0047] Optionally, after the boiler is ignited and reaches the first load point, the natural gas supply is controlled to a first supply threshold, and each time the next load point is reached, the natural gas supply is increased by a second supply threshold.

[0048] Specifically, once the first load point is reached, the natural gas supply can be maintained at the first supply threshold, such as 150m³. 3 / h, and when the next load point is reached, the natural gas supply increases by a second supply threshold, such as 150m³. 3 / h, reaching 300m 3 / h, and then each time the second supply threshold is increased until the maximum load point is reached.

[0049] Optionally, the total air supply volume is controlled to be at least 10 times the natural gas supply volume.

[0050] Specifically, as the natural gas supply gradually increases, the total air volume should increase proportionally. The total air volume can be more than 10 times the natural gas supply. In this embodiment, the total air volume is 11 times the natural gas supply, that is, when the natural gas supply is 150m³. 3 At / h, the total air supply volume is 1650m³. 3 / h.

[0051] Reference Figures 3 to 5 The natural gas boiler is commissioned and controlled using the natural gas boiler commissioning and operation method described above. It includes a boiler body 1, a burner 2, a gas pipeline assembly, an air inlet pipe 3, an exhaust pipe 4, an FGR pipeline assembly 5, and a detection module. The burner 2 is located in the boiler body 1; the gas pipeline assembly is connected to the burner 2 to deliver gas to the burner 2 in a primary and secondary gas ratio; one end of the air inlet pipe 3 is connected to the burner 2, and the other end is equipped with an air supply device for supplying air and adjusting the total air intake; the exhaust pipe 4 is located at the exhaust port of the boiler body 1 to discharge flue gas; one end of the FGR pipeline assembly 5 is connected to the exhaust pipe 4, and the other end is connected to the air inlet pipe 3 to circulate and guide a portion of the flue gas into the air inlet pipe 3; the detection module is used to detect the total air intake, primary gas ratio, secondary gas ratio, FGR smoke extraction volume, oxygen content of the discharged flue gas, and nitrogen oxide (NOx) content. The control module is communicatively connected to the detection module, the gas pipeline assembly, the air supply device, and the FGR pipeline assembly 5.

[0052] During operation, the natural gas boiler supplies gas to burner 2 via gas pipe assembly at primary and secondary gas ratios. Simultaneously, air supply assembly supplies air to burner 2 through air inlet pipe 3. After the gas and air mix, they are ignited and fully combusted within the furnace body 1. The flue gas generated during combustion is discharged through exhaust pipe 4, and a portion of the discharged flue gas is recycled back to air inlet pipe 3 via FGR pipe assembly 5. The detection module monitors the total air intake, primary gas ratio, secondary gas ratio, FGR smoke extraction volume, oxygen content of the exhaust gas, and nitrogen oxide (NOx) content in real time, and feeds the detection results back to the control module. The control module adjusts the natural gas boiler using the aforementioned commissioning and operation methods, ensuring that each load point of the natural gas boiler meets the requirements for energy saving and pollution reduction, thereby effectively improving the overall performance of the natural gas boiler.

[0053] To improve the quality of the recirculated flue gas, a first economizer 41 and a second economizer 42 are sequentially installed on the exhaust pipe 4. The connection port between the FGR pipe assembly 5 and the exhaust pipe 4 is located between the first economizer 41 and the second economizer 42, ensuring that the recirculated flue gas passes through at least the first economizer 41 before entering the intake pipe 3, while the discharged flue gas passes through the first economizer 41 and the second economizer 42 sequentially before being discharged outdoors through the chimney 6. An electrically driven movable baffle 51 can be installed on the FGR pipe assembly 5, allowing for flexible adjustment of the amount of flue gas drawn into the FGR pipe assembly 5 by changing its connection area.

[0054] Optionally, the air supply device includes a variable frequency fan 7 and an air inlet damper 8. The exhaust port of the variable frequency fan 7 is connected to the air inlet pipe 3; the air inlet damper 8 is movably connected to the air inlet of the air inlet pipe 3 to adjust the connection area of ​​the air inlet.

[0055] Specifically, an exhaust pipe 72 is provided at the exhaust port of the variable frequency fan 7, and an electric baffle 71 is provided at the opening of the exhaust pipe 72 to adjust the connection area of ​​the exhaust pipe 72. The exhaust port of the variable frequency fan 7 is connected to the inlet pipe 3. An inlet baffle 8 is embedded at the end of the inlet pipe 3 near the burner 2. The inlet baffle 8 can be equipped with an electric module for automatic control. The electric module is connected to the control module. By rotating the inlet baffle 8, the connection area between the inlet pipe 3 and the outside can be adjusted, thereby adjusting the total air volume according to the demand.

[0056] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for commissioning and operating a natural gas boiler, characterized in that, include: After supplying gas and air to the burner and igniting it, the system operates to the load point, controlling the primary gas ratio within the first range and the secondary gas ratio within the second range, while simultaneously controlling the FGR smoke extraction gas volume within the third range. The combustion state inside the boiler is obtained, and the primary fuel gas ratio and the secondary fuel gas ratio are adjusted according to the combustion state. Obtain the oxygen content of the emitted flue gas, and adjust the total air intake of the boiler during operation based on the oxygen content; The amount of nitrogen oxides (NOx) in the emitted flue gas is obtained, and the amount of flue gas drawn by the FGR is adjusted according to the amount of nitrogen oxides (NOx); When the combustion state, the oxygen content of the flue gas, and the nitrogen oxide (NOx) content of the flue gas all meet the requirements, the system will run to the next load point and repeat the above process for debugging.

2. The method for commissioning and operating a natural gas boiler according to claim 1, characterized in that, The process of obtaining the combustion state inside the boiler and adjusting the primary and secondary fuel gas ratios based on the combustion state specifically includes: The stability of the flame in the combustion zone is obtained, and the primary fuel gas ratio is adjusted according to the stability of the flame in the combustion zone to ensure that the primary fuel gas ratio is greater than 85%.

3. The method for commissioning and operating a natural gas boiler according to claim 1, characterized in that, The process of obtaining the combustion state inside the boiler and adjusting the primary and secondary fuel gas ratios based on the combustion state specifically includes: The boiler furnace temperature is obtained. When the furnace temperature is less than a first threshold, the secondary fuel gas ratio is increased. When the furnace temperature is greater than a second threshold, the secondary fuel gas ratio is decreased. When the furnace temperature is between the first threshold and the second threshold, the secondary fuel gas ratio is maintained. Wherein, the second threshold is greater than the first threshold.

4. The method for commissioning and operating a natural gas boiler according to claim 1, characterized in that, The adjustment of the total air intake volume specifically includes: Adjust the fan frequency or adjust the connectivity area of ​​the air inlet channel.

5. The method for commissioning and operating a natural gas boiler according to claim 1, characterized in that, The process of obtaining the amount of nitrogen oxides (NOx) in the emitted flue gas and adjusting the amount of flue gas drawn by the FGR based on the amount of nitrogen oxides (NOx) specifically includes: When the amount of nitrogen oxides (NOx) in the emitted flue gas is greater than a first preset concentration, the amount of flue gas drawn by the FGR is increased.

6. The method for commissioning and operating a natural gas boiler according to claim 1, characterized in that, Once the boiler is ignited and reaches the first load point, the natural gas supply is controlled to a first supply threshold. After reaching the next load point, the natural gas supply is increased by a second supply threshold.

7. The method for commissioning and operating a natural gas boiler according to any one of claims 1 to 6, characterized in that, The amount of smoke drawn by the FGR is controlled to be greater than 5% and less than 15% of the total smoke volume.

8. The method for commissioning and operating a natural gas boiler according to claim 6, characterized in that, The total air supply volume is controlled to be at least 10 times the natural gas supply volume.

9. A natural gas boiler, characterized in that, The commissioning and operation method for a natural gas boiler as described in any one of claims 1 to 8 includes the following: Furnace body (1); A burner (2) is disposed in the furnace body (1); A gas pipeline assembly is connected to the burner (2) to deliver gas to the burner (2) in a ratio of primary gas ratio and secondary gas ratio; The air inlet pipe (3) is connected to the burner (2) at one end and is equipped with an air supply device at the other end for supplying air and adjusting the total air volume. An exhaust pipe (4) is provided at the exhaust port of the furnace body (1) for discharging flue gas; The FGR pipe assembly (5) is connected at one end to the exhaust pipe (4) and at the other end to the air inlet pipe (3) to circulate and guide part of the flue gas into the air inlet pipe (3); The detection module is used to detect the total air intake volume, primary gas ratio, secondary gas ratio, FGR smoke extraction volume, oxygen content of exhaust gas, and nitrogen oxide (NOx) content. The control module is communicatively connected to the detection module, the gas pipe group, the air supply device and the FGR pipe group (5).

10. The natural gas boiler according to claim 9, characterized in that, The air supply device includes: A variable frequency fan (7) is embedded in the air inlet pipe (3); An air inlet baffle (8) is movably connected to the air inlet of the air inlet pipe (3) to adjust the connectivity area of ​​the air inlet.

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