Multi-mode methanol turbulent burner

Abstract

The invention relates to the technical field of combustion of gas turbines, and particularly discloses a multi-mode methanol turbulent burner which mainly comprises a main combustion stage sleeve, an on-duty stage sleeve, a main combustion stage swirler, an on-duty stage swirler, a main combustion stage methanol reformer, an on-duty stage methanol reformer, an on-duty stage nozzle and the like. The combustor has three working modes: methanol liquid mist, methanol steam and methanol reforming. In the ignition starting stage, the on-duty nozzle sprays liquid methanol to form methanol liquid mist, and reliable ignition and combustion are achieved; under the partial load working condition, the on-duty stage and the main combustion stage jet methanol steam absorbing exhaust waste heat, and the heat efficiency of the gas turbine is improved; under the full-load working condition, methanol is reformed into hydrogen-rich reformed gas in the combustor, the hydrogen-rich reformed gas enters the combustion chamber to be combusted, the heat efficiency is further improved, and emission of unconventional pollutants is reduced. The multi-mode methanol turbulent burner can meet the flexible combustion requirements under different working conditions, meanwhile, the heat efficiency of a gas turbine is improved, and pollutant emission is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of gas turbine combustion, and in particular to a multi-mode methanol swirl burner. Background Art

[0002] According to the International Energy Agency's forecast, the global energy structure will undergo major changes under the carbon neutrality scenario, and a high proportion of 70% renewable energy will be connected to the new power system. As the amount of renewable energy power generation increases, the challenges of power supply security and the demand for power balance will also increase. The volatility and randomness of wind and solar power generation make the power system insufficient to support loads under extreme conditions. Renewable energy represented by wind power and solar energy has the disadvantage of instability, which leads to the increasingly prominent problem of "abandoning wind and light". In the first quarter of 2024, my country's abandonment rates of light and wind were 4% and 3.9% respectively, an increase of 2% and 0.7% year-on-year, respectively, and the loss of output value was about 2 billion yuan. The large-scale consumption of renewable energy has become a bottleneck problem in the transformation of the energy structure.

[0003] The preparation of green fuels such as methanol provides an effective way to consume renewable energy on a large scale and achieve long-term energy storage. Through the electrolysis of water with renewable energy to produce hydrogen, coupled with carbon dioxide capture and conversion technology, green methanol can be catalytically synthesized. Green methanol has significant advantages in energy conversion and storage and transportation. Its transportation cost is only 2.3% to 8.4% of hydrogen. It has good storage and transportation safety and mature preparation technology. Therefore, it is considered to be a low-cost, long-term energy storage and good carrier for green electricity consumption.

[0004] However, methanol, as a liquid fuel with low boiling point, low flash point and high latent heat of vaporization, has the risks of flashback, flameout and local ablation when used in gas turbines. At present, most swirl burners on the market are mainly suitable for fuels such as methane (such as Chinese patent application CN108844063A), hydrogen (such as Chinese patent application CN117028989A), and ammonia (such as Chinese patent application CN118687148A). There is no swirl burner suitable for methanol gas turbine combustion. In summary, based on the actual needs of the project, the present invention designs a multi-mode methanol swirl burner, which can automatically switch between three modes of methanol liquid mist, methanol steam and methanol reforming according to the operating state of the burner, effectively utilizing the waste heat of the burner to improve the thermal efficiency of the gas turbine and reduce pollutant emissions. Summary of the invention

[0005] The invention discloses a multi-mode methanol swirl burner, which adopts a radial staged combustion organization mode and is composed of a central duty class and an outer main combustion class. The design combines diffusion combustion and lean premixed combustion to achieve efficient combustion and low pollution emissions under different working conditions. The duty class is mainly responsible for flame stabilization and adopts diffusion combustion; the main combustion class reduces NOx emissions and improves combustion efficiency through lean premixed combustion.

[0006] The main structure of the present invention includes: a main combustion stage sleeve, a duty class sleeve, a main combustion stage cyclone, a duty class cyclone, a main combustion stage methanol reformer, a duty class methanol reformer, a main combustion stage end cooling hole, a duty class end cooling hole, a main combustion stage fuel pipeline, a duty class fuel pipeline and a duty class nozzle. Air enters the main combustion stage and the duty class from the periphery of the main combustion stage cyclone and the bottom of the burner respectively to ensure the reasonable distribution of air supply.

[0007] The main combustion stage sleeve is made of materials that are resistant to methanol corrosion at high temperatures, preferably stainless steel or other corrosion-resistant alloys. Its bottom is connected to the top of the main combustion stage cyclone; the top flow channel is gradually reduced, and the angle between the contraction angle and the axis is 20°-40° to accelerate the airflow to prevent backfire; there is a main combustion stage end cooling hole with a diameter of 0.5mm-2.5mm and an angle between the inclination angle and the axis of 10°-30°, which is used to cool the end of the main combustion stage sleeve to prevent ablation.

[0008] The duty class sleeve is made of materials that are resistant to methanol corrosion at high temperatures, preferably stainless steel or other corrosion-resistant alloys. Its bottom is connected to the bottom of the main combustion stage cyclone, and its top flow channel is gradually reduced, with a contraction angle of 20°-40° with the axis, which is used to accelerate the airflow to assist methanol atomization; the diameter of the cooling hole at the end of the duty class is 0.5mm-2.5mm, and the angle of inclination with the axis is 10°-30°, which is used to cool the end of the duty class sleeve to prevent ablation.

[0009] The main combustion stage cyclone is preferably a radial cyclone, and an axial cyclone can also be selected, and its structure includes swirl blades, injection holes and a fuel cavity. The top of the main combustion stage cyclone is connected to the main combustion stage sleeve, and the bottom is connected to the duty class sleeve; the bottom of the main combustion stage cyclone is connected to 1-8 main combustion stage fuel pipelines, and there is an annular cavity, i.e., a fuel cavity, in the main combustion stage cyclone; the bottom of the fuel cavity is equipped with a main combustion stage methanol reformer, which can reform methanol into hydrogen-rich reforming gas under high temperature conditions; there are injection holes with a diameter of 0.5mm-5mm on the swirl channel, and the number is 6-24; after the fuel is ejected from the injection hole, it is fully mixed with the high-speed air in the swirl channel; the installation angle of the swirl blade is 30°-70°, the swirl number is 0.5-1, and 6-16 are evenly distributed along the circumference. By reasonably designing the swirl number, stable, efficient and low-pollution combustion of the burner under high load can be achieved.

[0010] The on-duty cyclone is preferably an axial cyclone, and a radial cyclone may also be selected, having 6-16 cyclone blades with a thickness of 0.5mm-5mm uniformly distributed along the circumference, a height of 10mm-50mm, and a swirl number of 0.5-1. The swirl number can be reasonably designed to enhance the atomization effect of liquid methanol and achieve reliable ignition of the burner and stable combustion under low load.

[0011] The duty class fuel pipeline is connected to the duty class nozzle; the duty class nozzle is provided with injection holes with a hole diameter of 0.5mm-5mm, and 6-16 holes are evenly distributed along the circumference; the angle between the fuel injection direction of the duty class nozzle and the axis is 45°-70°; a duty class methanol reformer is provided in the middle of the duty class fuel pipeline, which can reform methanol vapor into hydrogen-rich reforming gas under high temperature conditions.

[0012] Working principle of the present invention:

[0013] The multi-mode methanol swirl burner of the present invention can automatically switch between three combustion modes of methanol liquid mist, methanol vapor, and methanol reforming according to different operating conditions. In the present invention, liquid methanol absorbs exhaust waste heat and is gradually heated to a gaseous state when passing through the heat exchanger, and as the gas turbine operating conditions are further improved, methanol vapor is heated to the temperature required for autothermal reforming. The operating mode of the burner is determined by the operating conditions of the gas turbine and the temperature of the methanol at the burner inlet:

[0014] When the burner is in the ignition startup stage, methanol remains in liquid state due to the low exhaust waste heat. At this time, the burner is in methanol liquid mist mode, the duty class nozzle sprays methanol liquid mist into the combustion chamber, and the main combustion stage is not started. The duty class adopts the diffusion combustion mode to ensure the flame stability and smooth ignition.

[0015] When the burner enters partial load operation, the exhaust waste heat gradually increases, the liquid methanol is heated to gaseous state through the heat exchanger, and the burner enters mode II (methanol steam mode). In this mode, methanol steam is introduced into the main combustion stage and the duty stage, forming a methanol steam swirl flame in the combustion chamber, ensuring uniform and stable combustion, improving the thermal efficiency of the gas turbine, and reducing the emission of conventional pollutants such as NOx.

[0016] Under full load conditions, methanol vapor is further heated and reaches the temperature required for autothermal reforming, at which point the burner enters mode III (methanol reforming mode). In this mode, methanol vapor in the main combustion stage and duty stage is converted into hydrogen-rich reforming gas by the methanol reformer and sprayed into the combustion chamber to participate in combustion. Hydrogen-rich reforming gas can significantly reduce the emission of unconventional pollutants such as formaldehyde, while further improving the thermal efficiency of the gas turbine. The reforming mode can effectively utilize the waste heat of the gas turbine exhaust, and is particularly suitable for continuous operation of the burner under high load.

[0017] The burner of the present invention can automatically switch between three working modes according to the methanol temperature at the burner inlet. Methanol first enters the heat exchanger in liquid form to absorb exhaust waste heat; as the exhaust temperature rises, methanol gradually converts into gaseous form and enters mode II; under full load conditions, methanol is further heated and converted into hydrogen-rich reformed gas through the reformer, entering mode III. This switching process does not require manual operation and can be automatically completed according to the operating status of the gas turbine, ensuring that the burner operates efficiently and stably under different load conditions.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) Structural design of swirl burner coupled with methanol reforming

[0020] The present invention integrates a small methanol reformer into the main combustion stage and duty class channel of a swirl burner. When the methanol at the burner inlet reaches a certain temperature, the methanol undergoes a reforming reaction in the burner to generate hydrogen-rich reforming gas. This structure realizes efficient reforming of methanol under confined space conditions.

[0021] (2) Multi-mode combustion flexibility and high thermal efficiency

[0022] The present invention combines three combustion modes: methanol liquid mist, methanol steam and methanol reforming, and can flexibly switch the combustion mode according to different operating stages of the gas turbine (ignition start-up, partial load, full load). This design not only meets the needs of the burner under different load conditions, but also improves the thermal efficiency of the gas turbine by efficiently utilizing the exhaust waste heat during the combustion process, so that the gas turbine can maintain efficient operation under various operating conditions.

[0023] (3) Reduce pollutant emissions

[0024] The present invention adopts a radial staged combustion mode that combines diffusion combustion in the duty stage with lean premixed combustion in the main combustion stage, and achieves low pollutant emissions under different working conditions through flexible combustion mode conversion. The use of lean premixed combustion significantly reduces the emission of conventional pollutants such as NOx and CO, and the methanol reforming mode further utilizes the combustion characteristics of hydrogen-rich gas to reduce the emission of unconventional pollutants such as formaldehyde. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a multi-mode methanol swirl burner of the present invention;

[0026] Figure 2 It is a schematic diagram of the main combustion stage cyclone of the present invention;

[0027] Figure 3 A schematic diagram of the internal flow channel of a multi-mode methanol swirl burner of the present invention;

[0028] Figure 4 It is a schematic diagram of multi-mode combustion of the present invention;

[0029] Figure 5 A schematic diagram of a methanol gas turbine system of the present invention;

[0030] Figure 6 A schematic diagram of a methanol gas turbine system with a carbon capture device according to the present invention;

[0031] In the figure: 1. main combustion stage sleeve; 2. duty class sleeve, 3. duty class nozzle; 4. main combustion stage cyclone; 4-1. cyclone blades; 4-2. injection hole; 4-3. fuel cavity, 5. main combustion stage fuel pipeline; 6. main combustion stage methanol reformer; 7. duty class methanol reformer; 8. duty class cyclone; 9. duty class fuel pipeline; 10. duty class end cooling hole; 11. main combustion stage end cooling hole. DETAILED DESCRIPTION

[0032] Example 1

[0033] This embodiment describes the application of a multi-mode methanol swirl burner in a gas turbine. The burner is designed with three combustion modes, which can automatically switch to the appropriate mode according to the load state of the gas turbine and the temperature of the methanol at the burner inlet, so as to improve the thermal efficiency of the gas turbine and reduce the emission of conventional and unconventional pollutants. The liquid methanol fuel absorbs the exhaust waste heat through the heat exchanger to gradually achieve gasification and continue to heat until the temperature required for the reforming reaction is reached.

[0034] During the ignition and startup phase, the exhaust temperature of the gas turbine is low, and the exhaust waste heat is not enough to heat the methanol to a gaseous state. At this time, the burner is in the methanol liquid mist mode. In this mode, methanol is sprayed into the combustion chamber in the form of liquid atomization through the duty class nozzle. The duty class nozzle is designed with multiple injection holes with an aperture of 0.5mm-5mm, evenly distributed along the circumference, and the injection angle is 45°-70°, ensuring that the liquid methanol enters the combustion chamber evenly and diffuses and burns. Diffusion combustion contributes to the stability of the flame and avoids the flashback and flameout that may occur during the ignition and startup process. In this stage, only the duty class works, and the main combustion stage does not participate in the combustion.

[0035] As the load of the gas turbine increases, the exhaust temperature gradually rises, the liquid methanol is heated to a gaseous state, and the burner switches to the methanol steam mode. In this mode, methanol vapor enters the main combustion stage and the duty class at the same time, forming a methanol vapor swirl flame in the combustion chamber. The main combustion stage swirler is preferably a radial swirler, which is provided with swirl blades and a fuel cavity inside. Methanol vapor is ejected through the injection holes on the swirl channel and is fully mixed with the high-speed air in the swirl channel. The material of the main combustion stage sleeve is stainless steel or other corrosion-resistant alloys, the top flow channel is gradually reduced, and the angle between the contraction angle and the axis is 20°-40°. There is a main combustion stage end cooling hole with a diameter of 0.5mm-2.5mm, which is used to cool the end of the main combustion stage sleeve to prevent ablation. In this mode, the lean premixed combustion of the main combustion stage is combined with the diffusion combustion mode of the duty class to achieve higher combustion uniformity and stability, while reducing the emission of conventional pollutants such as NOx and improving the thermal efficiency of the gas turbine.

[0036] When the gas turbine reaches full load, the exhaust temperature rises further. After passing through the heat exchanger, the methanol vapor is further heated and reaches the temperature required for the autothermal reforming reaction, and the burner enters the methanol reforming mode. A combustion aid and a duty-class methanol reformer are respectively provided at the bottom of the main combustion stage cyclone fuel chamber and in the duty-class fuel pipeline, which can convert methanol vapor into hydrogen-rich reformed gas under high temperature conditions. The generated hydrogen-rich reformed gas enters the combustion chamber through the fuel pipeline for full combustion, thereby further improving the combustion efficiency and reducing the emission of conventional pollutants such as NOx and CO and unconventional pollutants such as formaldehyde. The methanol reforming mode makes full use of the exhaust waste heat and is suitable for long-term and efficient operation under high load conditions.

[0037] During the entire operation process, the burner's operating mode is automatically switched by the temperature change of the methanol at the inlet. When the methanol is heated from liquid to gas and further converted into hydrogen-rich reformed gas, the burner completes the conversion of the combustion mode through physical and chemical processes. This temperature-based adaptive switching mechanism enables the burner to achieve efficient and stable operation under various load conditions of the gas turbine.

[0038] Example 2

[0039] This embodiment describes the application of an improved multi-mode methanol swirl burner in a gas turbine. This embodiment adds a separation membrane device on the basis of a methanol reformer to separate CO from the methanol reformed gas. 2 and hydrogen-rich reformed gas, the separated CO 2 The hydrogen-rich gas is stored in a carbon storage tank under pressure and then enters the burner for combustion. This design can significantly reduce carbon emissions, further enhance the environmental performance of the system, and provide a solution for future low-carbon / zero-carbon power plants.

[0040] During the ignition and startup phase of the gas turbine, the exhaust temperature is low and insufficient to heat methanol to a gaseous state. At this point, the burner is in methanol liquid mist mode, and liquid methanol is atomized through the duty class nozzle and enters the combustion chamber for combustion. The diffusion combustion design of the duty class stabilizes the flame, thus ensuring the smooth startup of the gas turbine. The main combustion stage is not working at this stage, and carbon capture is not involved.

[0041] When the load of the gas turbine gradually increases, the exhaust temperature rises, the methanol is heated to a gaseous state, and the burner enters the methanol steam mode. In this mode, the main combustion stage methanol steam is ejected from the injection hole of the swirl channel and fully mixed with the high-speed air in the swirl channel to form a uniform lean premixed combustion; the duty-stage methanol steam is ejected from the duty-stage nozzle and mixed with the high-speed air in the combustion chamber to form a diffusion combustion. This stage does not involve carbon capture. By utilizing the waste heat of the gas turbine exhaust, the thermal efficiency of the gas turbine is improved, and the emission of conventional pollutants such as NOx is reduced.

[0042] When the gas turbine enters full load operation, the exhaust temperature rises further, the methanol vapor is heated to the temperature required for the autothermal reforming reaction through the heat exchanger, and the burner enters the methanol reforming mode. In this mode, the high-temperature methanol vapor is converted into methanol reforming gas under the action of the methanol reformer. After passing through the separation membrane, the methanol reforming gas is separated into CO 2 and hydrogen-rich gas. The separated CO 2 The gas is stored in a carbon storage tank under pressure to reduce carbon emissions; the hydrogen-rich gas enters the main combustion stage and duty stage of the burner and is mixed with air for combustion. This mode improves the thermal efficiency of the gas turbine and can achieve synergistic effects in reducing pollution and carbon emissions.

[0043] The carbon capture device is set up on the basis of the original device. By adding a carbon dioxide separation membrane device, carbon dioxide capture is achieved, and carbon emissions are significantly reduced. It provides a more environmentally friendly solution for the application of green methanol in gas turbines, and also provides a solution for the construction of future low-carbon / zero-carbon power plants.

[0044] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A multi-mode methanol swirl burner, characterized in that: A radial staged combustion organization mode is adopted, which is composed of a duty class in the center and a main combustion class on the outside; the duty class adopts diffusion combustion for flame stabilization, and the main combustion stage adopts lean premixed combustion for reducing NOx emissions; the burner comprises a main combustion stage sleeve, a duty class sleeve, a main combustion stage swirler, a duty class swirler, a main combustion stage methanol reformer, a duty class methanol reformer, a main combustion stage end cooling hole, a duty class end cooling hole, a main combustion stage fuel pipeline, a duty class fuel pipeline and a duty class nozzle; Air enters the main combustion stage and the duty class from the periphery of the main combustion stage swirler and the bottom of the burner respectively; the main combustion stage fuel is ejected through the injection holes evenly distributed on the fuel chamber, and the duty class fuel is ejected through the duty class nozzles; the burner supports multi-mode combustion modes, including methanol liquid mist mode, methanol steam mode and methanol reforming mode, to meet the flexible combustion requirements under different operating conditions, improve the thermal efficiency of the gas turbine and reduce pollutant emissions.

2. A multi-mode methanol swirl burner according to claim 1, characterized in that: The main combustion stage sleeve is made of a material that is resistant to methanol corrosion at high temperatures, and may be stainless steel or other corrosion-resistant alloy materials; the bottom of the main combustion stage sleeve is connected to the top of the main combustion stage cyclone; the flow channel at the top of the main combustion stage sleeve is gradually reduced, and the angle of reduction with the axis is 20°-40°, which is used to accelerate the airflow to prevent backfire; there is a cooling hole at the top of the main combustion stage sleeve, with a diameter of 0.5mm-2.5mm, and an inclination angle of 10°-30° with the axis, which is used to cool the end of the main combustion stage sleeve to prevent ablation.

3. The multi-mode methanol swirl burner according to claim 1, characterized in that: The duty class sleeve is made of a material that is resistant to methanol corrosion at high temperatures, and may be stainless steel or other corrosion-resistant alloy materials; the bottom of the duty class sleeve is connected to the bottom of the main combustion stage cyclone; the flow channel at the top of the duty class sleeve is gradually reduced, and the angle of reduction is 20°-40° with the axis, which is used to accelerate the airflow to assist methanol atomization; there is a cooling hole at the top of the duty class sleeve, with a diameter of 0.5mm-2.5mm and an inclination angle of 10°-30° with the axis, which is used to cool the end of the duty class sleeve to prevent ablation.

4. The multi-mode methanol swirl burner according to claim 1, characterized in that: The main combustion stage swirler can be a radial swirler or an axial swirler, and its structure includes swirl blades, injection holes and a fuel cavity; the top of the main combustion stage swirler is connected to the main combustion stage sleeve, and the bottom is connected to the duty stage sleeve; there is an annular fuel cavity in the main combustion stage swirler, and 1-8 main combustion stage fuel pipelines are connected to the bottom; a main combustion stage methanol reformer is arranged at the bottom of the fuel cavity, and methanol can be reformed into hydrogen-rich gas under high temperature conditions; there are injection holes with a diameter of 0.5mm-5mm on the swirl channel, and the number is 6-24; after the fuel is sprayed out from the injection hole, it is fully mixed with the high-speed air in the swirl channel; the installation angle of the swirl blade is 30°-70°, the swirl number is 0.5-1, and 6-16 are evenly distributed along the circumference. The swirl number can be reasonably designed to improve the premixing effect of fuel and air, and realize stable, efficient and low-pollution combustion of the burner under high load.

5. The multi-mode methanol swirl burner according to claim 1, characterized in that: The on-duty cyclone can be an axial cyclone or a radial cyclone, and has 6-16 cyclone blades with a thickness of 0.5mm-5mm and a height of 10mm-50mm evenly distributed along the circumference, and a swirl number of 0.5-1. The atomization effect of liquid methanol can be enhanced by reasonably designing the swirl number, thereby achieving reliable ignition of the burner and stable combustion under low load.

6. The multi-mode methanol swirl burner according to claim 1, characterized in that: The duty class fuel pipeline is connected to the duty class nozzle; the duty class nozzle is provided with injection holes with a hole diameter of 0.5mm-5mm, and 6-16 holes are evenly distributed along the circumference; the angle between the fuel injection direction of the duty class nozzle and the axis is 45°-70°; a duty class methanol reformer is provided in the middle of the duty class fuel pipeline, which can reform the methanol vapor into hydrogen-rich reforming gas when the methanol vapor reaches above 300°C.

7. The multi-mode methanol swirl burner according to claim 1, characterized in that: The multi-mode combustion method includes methanol liquid mist, methanol steam and methanol reforming modes, specifically: in the ignition startup stage, the duty class nozzle sprays liquid methanol to form methanol liquid mist at the burner outlet, which can achieve reliable ignition and combustion; under partial load conditions, the duty class and the main combustion stage jointly spray methanol steam to form a methanol steam swirl flame in the combustion chamber to improve the thermal efficiency of the gas turbine and reduce conventional pollutant emissions; Under full load conditions, methanol vapor is further heated to reach the temperature required for autothermal reforming. After passing through the duty-stage and main combustion-stage methanol reformers, it is converted into hydrogen-rich reformed gas and fully burned in the combustion chamber, which can further improve the thermal efficiency of the gas turbine and reduce the emission of unconventional pollutants.

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