Boiler gas supply system and method

Abstract

The present application relates to the technical field of combustion and discloses a boiler gas supply system and method, the boiler gas supply system comprising a furnace body, a gas burner, a first combustion-supporting gas unit and a fuel gas unit connected with the furnace body and the gas burner, the first combustion-supporting gas unit being used for supplying mixed gas of oxygen and carbon dioxide, and the fuel gas unit being used for supplying fuel gas, wherein when the first combustion-supporting gas unit and the fuel gas unit supply gas to the gas burner at the same time, the fuel gas and the mixed gas can be combusted in the gas burner, and the heat medium generated by the combustion enters the furnace body to heat the furnace body; when the fuel gas unit supplies gas to the furnace body only, the gas burner can serve as a channel to supply the mixed gas flowing therethrough into the furnace body, and the fuel gas and the mixed gas can be combusted in the furnace body. The boiler gas supply system of the present application can realize the supply of multiple gas media and line switching, so as to meet the requirements of furnace body preheating and oxygen-enriched combustion of multiple fuels.

Description

Technical Field

[0001] This invention belongs to the field of combustion technology, specifically relating to a boiler gas supply system and method. Background Technology

[0002] Currently, research on pressurized oxygen-enriched combustion, both domestically and internationally, largely focuses on small-scale or pilot-scale analysis of combustion characteristics and pollutant emissions, lacking systematic experimental studies on heat transfer processes and heat transfer coefficients under actual combustion conditions. Existing experimental setups are mostly based on simplified models such as "hot bed cold tube" or "heat tube cold bed," failing to simulate the complex material flow and heat transfer coupling processes within a real furnace. Furthermore, traditional boiler systems generally suffer from a single combustion mode and an inability to flexibly switch combustion methods, making it difficult to adapt to varying process requirements. Although some related technologies have attempted to use a mixture of oxygen and carbon dioxide as a combustion medium, shortcomings remain in areas such as multi-source gas supply coordination and dynamic combustion switching. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a boiler gas supply system that can simulate actual furnace combustion and realize the supply and switching of multiple gas media to meet the needs of preheating and oxygen-enriched combustion of various fuels.

[0004] This invention also proposes a boiler gas supply method that can achieve the supply of multiple gas media and smooth line switching to meet the needs of preheating and oxygen-enriched combustion of fuel gas or solid fuel.

[0005] The boiler gas supply system of this invention includes a boiler body, a gas burner, a first combustion-supporting unit, and a fuel gas unit. The gas burner is connected to the boiler body, the first combustion-supporting unit is connected to the boiler body and the gas burner, and is used to supply a mixture of oxygen and carbon dioxide to at least one of the boiler body and the gas burner. The fuel gas unit is connected to the boiler body and the gas burner, and is used to supply fuel gas to at least one of the boiler body and the gas burner.

[0006] When the first combustion-supporting unit and the fuel gas unit simultaneously supply gas to the gas burner, the fuel gas and the mixed gas can burn in the gas burner, and the heat medium generated by the combustion enters the furnace body to heat the furnace body. When the fuel gas unit only supplies gas to the furnace body, the gas burner can act as a channel to supply the mixed gas flowing through it into the furnace body, and the fuel gas and the mixed gas can burn in the furnace body.

[0007] The boiler gas supply system in this embodiment is adapted to pressurized oxygen-enriched combustion conditions. By switching between two modes of "combustion preheating in the burner + stable combustion in the furnace", it uses a mixture of oxygen and carbon dioxide as the combustion medium to meet the combustion needs of multiple fuels such as gas and solids. This significantly reduces the energy consumption of air separation and carbon capture in atmospheric pressure oxygen-enriched combustion, ensures stable combustion, and provides key support for the promotion of CCUS technology and related heat exchange experiments.

[0008] In some embodiments, the boiler gas supply system further includes a second gas-supporting unit connected to the gas burner for supplying air to the gas burner.

[0009] In some embodiments, the boiler gas supply system further includes a protective gas unit for supplying protective gas to the gas burner.

[0010] In some embodiments, the gas medium supplied by the first combustion-supporting unit, the second combustion-supporting unit, the fuel gas unit, and the protective gas unit has the same pressure, and the pressure range is 0-1.6 MPa.

[0011] In some embodiments, the furnace body includes a furnace chamber and a first air inlet, a second air inlet, and a third air inlet communicating with the furnace chamber; The first air inlet is connected to the outlet of the gas burner; The fuel gas unit is divided into two parallel paths, one of which is connected to the second air inlet, and the other is connected to the inlet of the gas burner. The first combustion-supporting unit is divided into two parallel paths, one of which is connected to the third air inlet, and the other is connected to the inlet of the gas burner.

[0012] In some embodiments, the first air inlet and the second air inlet are located in the bottom region of the furnace body.

[0013] In some embodiments, the third air inlet is located in the central region of the furnace body.

[0014] In some embodiments, the furnace body further includes a flue, on which a pressure regulating valve is provided for regulating the back pressure of the furnace body.

[0015] In some embodiments, the fuel gas includes at least one of dimethyl ether, natural gas, methane, and propane.

[0016] In some embodiments, the protective gas is at least one of nitrogen, argon, and helium.

[0017] The boiler gas supply system in this embodiment integrates multiple gas units, dual combustion modes, and a precise gas distribution structure. Combined with unified pressure control and safety protection design, it is suitable for pressurized oxygen-enriched combustion of gaseous and solid fuels, significantly reducing system energy consumption and carbon capture costs, ensuring stable and safe combustion, and providing reliable support for the promotion of CCUS technology and related experiments.

[0018] The boiler gas supply method of this invention is implemented using the boiler gas supply system described in any of the above embodiments, and includes a preheating gas supply stage and a combustion gas supply stage. Preheating gas supply stage: The first combustion-supporting unit and the fuel gas unit respectively supply the mixed gas and the fuel gas to the gas burner, so that the fuel gas and the mixed gas are burned in the gas burner and the furnace body is preheated until the furnace body reaches the preheating temperature, and then the fuel gas unit stops supplying the fuel gas to the gas burner; Combustion gas supply stage: The fuel gas unit supplies the fuel gas to the furnace body, and the first combustion-supporting unit supplies the mixed gas to the furnace body via the gas burner, so that the fuel gas and the mixed gas can be stably combusted in the furnace body; The volume percentage of oxygen in the mixed gas is 15%-30%.

[0019] In some embodiments, during the preheating gas supply phase, the first gas supply unit is replaced with the second gas supply unit to allow the fuel gas and the air to burn in the gas burner and preheat the furnace body until the furnace body reaches the preheating temperature; and during the combustion gas supply phase, the air supply of the second gas supply unit is gradually stopped, and the mixed gas is supplied to the central region of the furnace through the first gas supply unit.

[0020] The boiler gas supply method of this invention employs a two-step "preheating-stable combustion" approach. During the preheating stage, air is used to aid combustion, reducing costs and accelerating temperature rise. During the combustion stage, a mixture of oxygen and carbon dioxide is switched to adapt to pressurized, oxygen-enriched combustion of multiple fuels. This smooth switching of combustion gases ensures stable combustion, meets the requirements for accurate experimental data collection, and reduces energy consumption and carbon capture costs. Attached Figure Description

[0021] Figure 1 This is an overall schematic diagram of the boiler gas supply system according to an embodiment of the present invention.

[0022] Figure label: 1. Furnace body; 11. Furnace chamber; 12. First air inlet; 13. Second air inlet; 14. Third air inlet; 15. Flue; 16. Pressure regulating valve; 17. Air distribution plate; 18. Fluidizing nozzle; 19. Gas chamber; 110. Guide tube; 2. Gas burner; 3. First combustion-supporting unit; 4. Fuel gas unit; 5. Second combustion-supporting unit; 6. Protective gas unit. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. 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.

[0024] like Figure 1 As shown, the boiler gas supply system of this embodiment of the invention is characterized by comprising a boiler body 1, a gas burner 2, a first combustion-supporting unit 3, and a fuel gas unit 4. The gas burner 2 is connected to the boiler body 1, the first combustion-supporting unit 3 is connected to the boiler body 1 and the gas burner 2, and is used to supply a mixture of oxygen and carbon dioxide to at least one of the boiler body 1 and the gas burner 2. The fuel gas unit 4 is connected to the boiler body 1 and the gas burner 2, and is used to supply fuel gas to at least one of the boiler body 1 and the gas burner 2. When the first combustion-supporting unit 3 and the fuel gas unit 4 simultaneously supply gas to the gas burner 2, the fuel gas and the mixed gas can be burned in the gas burner 2, and the heat medium generated by the combustion enters the furnace body 1 to heat the furnace body 1. When the fuel gas unit 4 only supplies gas to the furnace body 1, the gas burner 2 can serve as a channel to supply the mixed gas flowing through it into the furnace body 1, and the fuel gas and the mixed gas can be burned in the furnace body 1.

[0025] The boiler gas supply system of this invention, through the rational configuration of the connection relationship between the furnace body 1, gas burner 2, first combustion-supporting unit 3, and fuel gas unit 4, realizes two different combustion gas supply modes to adapt to different operating conditions of the furnace body 1. The mixed gas, as the combustion-supporting gas, combined with a pressurized operating environment (system pressure adjustable from 0-1.6 MPa), effectively reduces the energy consumption of the air separation oxygen production and compression purification units in traditional atmospheric pressure oxy-fuel combustion systems, improving the economic efficiency of oxy-fuel combustion technology and providing strong support for the promotion and application of carbon capture, utilization, and storage (CCUS) technology. Simultaneously, the flexible switching between the two combustion modes ensures the combustion efficiency and stability of the furnace body 1 at different stages such as preheating and stable combustion, meeting the operating conditions requirements of a 100 kW-level pressurized oxy-fuel combustion heat exchange experiment.

[0026] In practical implementation, the furnace body 1 adopts a pressurized oxygen-enriched combustion furnace main structure, capable of withstanding working pressures of 0-1.6 MPa, providing a stable high-pressure environment for fuel combustion. Its internal furnace chamber 11 can accommodate the combustion needs of different fuels such as gaseous fuels, fluidized bed coal, or pulverized coal. The gas burner 2 is made of high-temperature resistant and corrosion-resistant metal. One end is sealed to the furnace body 1 to ensure no gas leakage during combustion, while the other end is connected to the first combustion-supporting unit 3 and the fuel gas unit 4, providing both combustion and gas flow guidance functions. The mixed gas in the first combustion-supporting unit 3 is a mixture of oxygen and carbon dioxide. The mixed gas is connected to the furnace body 1 and the gas burner 2 via branch pipelines, ensuring a stable gas supply to any target location. The fuel gas unit 4 includes a fuel gas storage tank and branch pipelines. The fuel gas stored in the storage tank can be one or more mixed gases selected from dimethyl ether, natural gas, methane, and propane. The fuel gas is connected to the furnace body 1 and the gas burner 2 via branch pipelines, enabling fuel supply to different locations.

[0027] In some specific embodiments, the first combustion-supporting unit 3 includes an oxygen storage device, a carbon dioxide storage device, a mixing tank, and a delivery pipeline. After the oxygen and carbon dioxide are output from the storage devices, they are uniformly mixed in the mixing tank at a volume ratio of 15%-30% oxygen to form a mixed gas.

[0028] When the furnace body 1 needs to be preheated, the first combustion mode is adopted: the first combustion-supporting unit 3 supplies mixed gas to the gas burner 2 through the corresponding branch pipeline, and the fuel gas unit 4 simultaneously supplies fuel gas to the gas burner 2 through the corresponding branch pipeline. The fuel gas and the mixed gas are fully mixed in the gas burner 2 and then ignited and burned. The high-temperature heat medium generated by combustion enters the furnace body 1 through the connection channel between the gas burner 2 and the furnace body 1, preheating the furnace chamber 11 and related internal structures (such as bed material) of the furnace body 1 until the furnace body 1 reaches the preheating temperature (e.g., 400-800℃).

[0029] After furnace body 1 has completed preheating, it switches to the second combustion mode: fuel gas unit 4 shuts off fuel supply to gas burner 2, supplying fuel gas only to the interior of furnace body 1 through a branch pipe connected to furnace body 1; at this time, gas burner 2 no longer performs combustion function, but only serves as a gas passage. The first combustion-supporting unit 3 supplies mixed gas to gas burner 2 through a branch pipe connected to gas burner 2. The mixed gas flows through gas burner 2 and enters the interior of furnace body 1, where it mixes thoroughly with the fuel gas and ignites, maintaining a stable combustion state inside furnace body 1. This provides stable combustion conditions for subsequent experimental processes in furnace body 1, such as heat transfer coefficient measurement and flue gas composition analysis. Throughout the gas supply process, the gas delivery pressure of each unit is adjusted to ensure a stable gas supply and meet the pressure requirements for pressurized oxygen-enriched combustion.

[0030] In some embodiments, the boiler gas supply system further includes a second gas-supporting unit 5, which is connected to the gas burner 2 and is used to supply air to the gas burner 2.

[0031] The boiler gas supply system of this invention adds a second combustion-supporting unit 5, which can use air as the combustion-supporting gas during the preheating stage of the furnace body 1. Air is widely available and its acquisition cost is much lower than that of a mixture of oxygen and carbon dioxide, which can significantly reduce the operating cost of the preheating stage. At the same time, air-supported combustion can quickly form a high-temperature combustion environment, ensuring the preheating speed and effect of the furnace body 1. Furthermore, the switching operation with the first combustion-supporting unit 3 is convenient, adapting to the different combustion-supporting requirements of the preheating and stable combustion stages, further improving the economy and adaptability of the boiler gas supply system, and meeting the design goals of low energy consumption and flexible operation of the pressurized oxygen-enriched combustion experimental device.

[0032] In practice, the second combustion-supporting unit 5 consists of an air storage device, a compression mechanism, and a dedicated delivery pipeline. The air storage device uses a well-sealed gas tank to store atmospheric pressure air. The compression mechanism employs a high-pressure compressor, which can compress the air pressure to a range compatible with other gaseous media in the system, ensuring stable gas delivery. The delivery pipeline uses high-temperature resistant and corrosion-resistant metal pipes, one end of which is fixedly connected to the output end of the second combustion-supporting unit 5, and the other end is sealed to the air inlet of the gas burner 2. This air inlet can be independently connected to the connection interfaces of the first combustion-supporting unit 3 and the fuel gas unit 4, or connected via tees and valves. During the preheating and gas supply stage of the furnace body 1, the second combustion-supporting unit 5 can be activated first. The air is pressurized by the compression mechanism and then delivered to the gas burner 2 through the delivery pipeline. Simultaneously, the fuel gas unit 4 supplies fuel gas to the gas burner 2. The fuel gas and air are fully mixed in the gas burner 2 and then ignited, rapidly generating a high-temperature heat medium of 800-1000℃, efficiently completing the preheating operation of the furnace body 1. Once the furnace body 1 reaches the preset preheating temperature of 400-800℃, it enters the combustion and gas supply stage. At this time, the second combustion-supporting unit 5 can be gradually shut off to stop the air supply, while the first combustion-supporting unit 3 is started to supply mixed gas to the gas burner 2, so as to achieve a smooth switching of combustion-supporting gas and ensure the stable operation of subsequent oxygen-enriched combustion in the furnace body 1.

[0033] In some embodiments, the boiler gas supply system further includes a protective gas unit 6, which supplies protective gas to the gas burner 2. The protective gas is at least one of nitrogen, argon, and helium.

[0034] The boiler gas supply system of this invention provides protection against potential safety risks during the start-up, operation, and shutdown of the gas burner 2 or the furnace body 1. The protective gas effectively purges residual fuel gas or gas mixtures from the gas burner 2 or the furnace body 1, preventing spontaneous combustion of residual gas and potential safety accidents. In case of unexpected flameout or other emergencies, the protective gas can be quickly introduced to interrupt combustion conditions, achieving emergency fire suppression and ensuring the safety of equipment and personnel. Simultaneously, the configuration of the protective gas unit 6 makes the boiler gas supply system more adaptable to the high-pressure, high-temperature conditions of pressurized oxygen-enriched combustion, further improving the reliability and safety of system operation and meeting the safe operation requirements of a 100-kilowatt-level pressurized oxygen-enriched combustion heat exchange experiment.

[0035] In practice, the protective gas unit 6 consists of a protective gas storage device, delivery pipelines, and control valves. The protective gas storage device is a high-pressure gas tank, and the protective gas stored inside is one or more mixed gases selected from nitrogen, argon, and helium. These gases are chemically stable, do not participate in combustion, and can isolate oxygen. During system startup, shutdown, or operation, the protective gas unit 6 is activated as needed to purge the gas burner 2, furnace body 1, and related pipelines to remove residual fuel gases and combustion products, thus avoiding safety hazards.

[0036] In some embodiments, the gas medium supplied by the first combustion-supporting unit 3, the second combustion-supporting unit 5, the fuel gas unit 4, and the protective gas unit 6 has the same pressure and the pressure range is 0-1.6 MPa.

[0037] In the boiler gas supply system of this invention, the four gas units have a consistent gas supply pressure and are limited to a pressure range of 0-1.6 MPa. This effectively avoids problems such as airflow turbulence and uneven gas mixing caused by pressure differences between units, ensuring the stability and continuity of the combustion process. This pressure range not only meets the core requirements of pressurized oxygen-enriched combustion systems to reduce energy consumption and improve economy, but also satisfies the flexibility requirements of pressure regulation for 100-kilowatt-level experimental devices. At the same time, the unified pressure standard simplifies the system pressure control logic, reduces the risk of pressure adaptation during equipment operation, and further improves the operational safety and reliability of the system under high-pressure conditions.

[0038] In practice, each gas unit is equipped with an independent pressure regulation module, including a booster device, a pressure reducing valve, and a pressure monitoring instrument, to ensure that the pressure of the gas output from each unit is accurately matched and stable within the set range. After the mixed gas in the first combustion-supporting unit 3 is mixed in the mixing tank, the pressure can be increased to the target value through the booster device. If the initial pressure meets the requirements, the pressure is stabilized through the pressure reducing valve. The air in the second combustion-supporting unit 5 is compressed by the compressor and then regulated to the set pressure by the pressure reducing valve. The fuel gas unit 4 and the protective gas unit 6 respectively regulate the pressure of the fuel gas and protective gas to be consistent with those of the other units through their respective pressure regulation devices.

[0039] The pressure monitoring instrument uses a high-precision pressure sensor to monitor the gas pressure at the outlet of each unit and in the delivery pipeline in real time, with a measurement accuracy of ±0.01MPa. When a pressure deviation occurs, the control system automatically triggers the booster device or pressure reducing valve to adjust, ensuring that the pressure difference among the four components does not exceed 0.05MPa. This pressure range covers the full operating conditions of pressurized oxy-fuel combustion experiments. The low-pressure range (0-0.5MPa) is suitable for low-load scenarios such as system preheating and commissioning, while the medium-high pressure range (0.5-1.6MPa) can meet the stable operation requirements of pressurized oxy-fuel combustion of gaseous fuels, coal-fired fluidized beds, and pulverized coal. In particular, the target pressure condition of around 1.5MPa can accurately match the pressure requirements of the experimental device for measuring combustion efficiency and heat transfer coefficient. At the same time, the unified pressure standard ensures stable flow rates of each gas during transportation and mixing, avoiding safety hazards such as pipeline vibration and gas leakage caused by sudden pressure changes, and ensuring long-term stable operation of the system.

[0040] In some embodiments, the furnace body 1 includes a furnace chamber 11, and a first air inlet 12, a second air inlet 13 and a third air inlet 14 communicating with the furnace chamber 11; The first air inlet 12 is connected to the outlet of the gas burner 2; The fuel gas unit 4 is divided into two parallel paths, one of which is connected to the second air inlet 13, and the other is connected to the inlet of the gas burner 2. The first combustion-supporting unit 3 is divided into two parallel paths, one of which is connected to the third air inlet 14, and the other is connected to the inlet of the gas burner 2.

[0041] In some embodiments, the first air inlet 12 and the second air inlet 13 are located in the bottom region of the furnace body 1.

[0042] In some embodiments, the third air inlet 14 is located in the central region of the furnace body 1.

[0043] The boiler gas supply system of this invention achieves precise gas distribution and uniform gas distribution by clearly defining the multi-inlet layout of the furnace body 1 and the branch connection method of the gas units, combined with the specific regional distribution of the inlets, and supplementary structures such as the air distribution plate 17 and the gas chamber 19. The first and second air inlets in the bottom region ensure sufficient contact between the fuel gas and the combustion-supporting gas in the lower part of the furnace 11, while the third air inlet 14 in the middle region supplements the combustion-supporting gas, optimizing the gas concentration distribution in the furnace 11 and avoiding incomplete combustion or excessively high temperatures in some areas. The design of the air distribution plate 17 and the fluidizing nozzle 18 further improves the uniformity of gas diffusion, adapts to the fluidization requirements of combustion modes such as coal-fired fluidized beds, and the multi-branch design allows the system to flexibly switch combustion conditions, ensuring the stability of different combustion stages. This provides a uniform and stable combustion environment for experiments such as heat transfer coefficient measurement and temperature and pressure distribution monitoring, improving the accuracy of experimental data.

[0044] In practical implementation, the furnace chamber 11 of the furnace body 1 provides the core space for pressurized oxygen-enriched combustion. Its internal dimensions are adapted to experimental requirements with a thermal power of 50-200KW and can withstand working pressures of 0-1.6MPa. The first air inlet 12 and the second air inlet 13 are both located in the bottom area of ​​the furnace body 1, and the third air inlet 14 is located in the middle area of ​​the furnace body 1. All three air inlets are sealed and connected to the inside of the furnace chamber 11 to ensure that there is no leakage during the gas delivery process.

[0045] In some specific embodiments, the furnace body 1 further includes an air distribution plate 17, a gas chamber 19, and a guide tube 110. The air distribution plate 17 is located at the lower part of the furnace chamber 11 and is provided with a plurality of fluidizing nozzles 18. The gas chamber 19 is located below the air distribution plate 17 and communicates with the plurality of fluidizing nozzles 18. The first air inlet 12 communicates with the gas chamber 19 so that the gas medium or heat medium passing through the gas burner 2 can be sprayed out from the fluidizing nozzles 18. The guide tube 110 penetrates the gas chamber 19, and the upper end of the guide tube 110 is positioned above the air distribution plate 17. The lower end of the guide tube 110 forms a second air inlet 13.

[0046] The main pipeline of the fuel gas unit 4 extends to the vicinity of the furnace body 1 and then splits into two parallel branches. One branch is directly and sealed to the second air inlet 13 (lower end of the guide tube 110), and the other branch is sealed to the inlet of the gas burner 2. Both branches can be equipped with independent control valves to adjust the fuel gas flow rate and on / off status separately. The main pipeline of the first combustion-supporting unit 3 is also divided into two parallel branches. One branch is sealed to the third air inlet 14, and the other branch is sealed to the inlet of the gas burner 2. Both branches can also be equipped with independent control valves to achieve mixed gas diversion control and flow rate regulation.

[0047] During the preheating stage, the first combustion-supporting unit 3 and the fuel gas unit 4 supply the heat medium generated by combustion to the gas burner 2. The heat medium enters the gas chamber 19 through the first air inlet 12 and is evenly sprayed into the furnace 11 through multiple fluidizing nozzles 18 on the air distribution plate 17. This uniformly preheats the furnace 11 and the bed material on the air distribution plate 17 (in the case of fluidized bed combustion) to avoid excessive local temperature differences. During the stable combustion stage, the fuel gas unit 4 delivers fuel gas into the furnace 11 through a branch connected to the second air inlet 13 and through a guide tube 110. The fuel gas is sprayed out from the upper end of the guide tube 110 and diffuses in the lower part of the furnace 11. The first combustion-supporting unit 3 delivers mixed gas to the middle of the furnace 11 through a branch connected to the third air inlet 14. At the same time, it replenishes mixed gas to the lower part of the furnace 11 through a branch connected to the gas burner 2, via the gas chamber 19 and the fluidizing nozzles 18. The gases in the upper and lower parts cooperate with each other to achieve full mixing and stable combustion of fuel gas and mixed gas. For coal-fired fluidized bed combustion, the mixed gas ejected by the fluidizing nozzle 18 can provide sufficient fluidization power for the bed material, maintain the fluidization state of the bed material, and ensure the stable operation of the combustion and heat exchange process.

[0048] In some embodiments, the furnace body 1 further includes a flue 15, on which a pressure regulating valve 16 is provided, which is used to regulate the back pressure of the furnace body 1.

[0049] In this embodiment of the invention, the boiler gas supply system adds a flue 15 with a pressure regulating valve 16 to the furnace body 1, achieving precise and controllable back pressure of the furnace body 1. This allows for linkage with the pressure regulation of each gas unit, ensuring that the pressure within the furnace 11 remains stable within the target range of 0-1.6 MPa. Stable back pressure avoids problems such as airflow turbulence and uneven mixing of fuel and combustion gases caused by pressure fluctuations during combustion, ensuring combustion efficiency and stability. It also adapts to the pressure requirements of different combustion modes, including gaseous fuels, fluidized bed coal combustion, and pulverized coal. Furthermore, adjusting the back pressure optimizes the flue gas flow velocity. Combined with the arrangement of heat exchange experimental devices within the furnace 11, such as heat exchangers and heat exchange probes, this provides a stable flow field environment for experiments such as heat transfer coefficient measurement and flue gas composition analysis, further improving the accuracy of experimental data. Simultaneously, it reduces the impact of sudden pressure changes on the furnace body 1 and pipelines, extending equipment lifespan and aligning with the design goals of high efficiency, stability, and safety for pressurized oxygen-enriched combustion experimental devices.

[0050] In practical implementation, flue 15 is made of high-temperature and corrosion-resistant alloy material. One end is sealed and connected to the top or upper part of the furnace 11, and the other end is connected to the flue gas treatment system (such as a cyclone separator) to ensure that the flue gas generated by combustion can be discharged smoothly without leakage. The inner diameter of flue 15 is designed according to the thermal power (50-200KW) and flue gas emission volume of the experimental system to ensure that the flue gas flow resistance is moderate and does not affect the sensitivity of back pressure regulation. The pressure regulating valve 16 is an electric regulating ball valve with high-precision regulation function, and the regulation accuracy can reach ±0.01MPa. Its installation position can be selected near the connection between flue 15 and furnace 11, so as to directly respond to the pressure change in furnace 11 and quickly adjust the valve opening; or it can be set at any point in flue 15.

[0051] In some specific embodiments, pressure measuring points can be set on the flue 15 or the furnace body 1. The pressure regulating valve 16 establishes a linkage control logic with the pressure measuring points. The pressure measuring points collect pressure data in the furnace 11 or the entire system in real time and transmit it to the control system. When the pressure is higher than the target value, the control system drives the pressure regulating valve 16 to increase the opening, accelerate the flue gas discharge speed, and reduce the back pressure. When the pressure in the furnace 11 is lower than the target value, the regulating valve decreases the opening, slows down the flue gas discharge, and increases the back pressure, ensuring that the pressure in the furnace 11 is always stable within the preset range. During the preheating stage, the back pressure is adjusted to a lower level (e.g., 0.1-0.3 MPa) by the pressure regulating valve 16, and in conjunction with the gas supply of the second combustion-supporting unit 5 or the first combustion-supporting unit 3, the low-temperature flue gas generated during preheating is quickly discharged, ensuring preheating efficiency. During the stable combustion stage, the back pressure is adjusted to the target value (e.g., 1.5 MPa for gaseous fuel combustion) according to different combustion modes. By precisely controlling the flue gas discharge speed, the airflow in the furnace 11 is kept stable, ensuring that the fuel gas and the mixed gas are fully mixed and burned. In addition, the pressure regulating valve 16 also has a manual emergency adjustment function. In the event of a failure in the automatic control system, the back pressure of the furnace body 1 can be maintained by manual operation, thereby improving the reliability of the system operation.

[0052] The following describes a boiler gas supply method according to an embodiment of the present invention, implemented using any of the boiler gas supply systems described above, including: Preheating gas supply stage: The first combustion-supporting gas unit 3 and the fuel gas unit 4 supply mixed gas and fuel gas to the gas burner 2 respectively, so that the fuel gas and mixed gas can burn in the gas burner 2 and preheat the furnace body 1 until the furnace body 1 reaches the preheating temperature, and then the fuel gas unit 4 stops supplying fuel gas to the gas burner 2. Combustion gas supply stage: Fuel gas unit 4 supplies fuel gas to furnace body 1, and first combustion-supporting unit 3 supplies mixed gas to furnace body 1 through gas burner 2 so that fuel gas and mixed gas can be stably combusted in furnace body 1; The volume percentage of oxygen in the gas mixture is 15%-30%.

[0053] In some embodiments, during the preheating gas supply stage, the first combustion-supporting unit 3 is replaced by a second combustion-supporting unit 5 to allow the fuel gas and air to burn in the gas burner 2 and preheat the furnace body 1 until the furnace body 1 reaches the preheating temperature; and during the combustion gas supply stage, the air supply of the second combustion-supporting unit 5 is gradually stopped; and the mixed gas is supplied to the central region of the furnace 11 through the first combustion-supporting unit 3. During the preheating gas supply stage, the air supply can be appropriately increased as needed to reduce the temperature of the heat medium generated after combustion and extend the life of the gas burner.

[0054] The boiler gas supply method of this invention adopts a two-step design of "preheating-stable combustion" to adapt to the full operating conditions of the furnace 1 from start-up to stable operation. The mixed gas with an oxygen volume ratio of 15%-30% can accurately match the efficiency and low carbon requirements of pressurized oxygen-enriched combustion, reducing carbon capture costs. At the same time, in the preheating gas supply stage, the air supplied by the second combustion-supporting unit 5 is used as the combustion-supporting gas, making full use of the advantages of wide availability and low cost of air, which significantly reduces the energy consumption of the preheating stage. Moreover, air-supported combustion can quickly increase the temperature of the furnace 1 and ensure preheating efficiency. The smooth switching of the combustion-supporting gas in the combustion gas supply stage not only avoids combustion interruption or operating condition fluctuations, but also seamlessly connects to the pressurized oxygen-enriched combustion mode, ensuring stable combustion and sufficient heat in the furnace 1. This provides a reliable operating condition basis for experiments such as heat transfer coefficient measurement and flue gas composition analysis, which is in line with the design goals of the 100-kilowatt-level pressurized oxygen-enriched combustion heat exchange experimental device.

[0055] In practice, first confirm the status of each unit of the boiler gas supply system, and ensure that the first combustion-supporting unit 3, the second combustion-supporting unit 5, the fuel gas unit 4, the protective gas unit 6, and the pressure regulating valve 16 are operating normally. The system pressure is preset to the target value in the range of 0-1.6MPa (e.g., 1.5MPa). The volume ratio of oxygen in the mixed gas is adjusted to 15%-30% according to the combustion mode requirements (e.g., it can be set to 21% when gaseous fuel is burned, and to 25% when coal-fired fluidized bed is burned).

[0056] Preheating and gas supply stage: The second combustion-supporting unit 5 is started, and compressed air is supplied to the gas burner 2 through its delivery pipeline. At the same time, the fuel gas unit 4 is started, and fuel gas (dimethyl ether or natural gas) is supplied to the gas burner 2 through the branch connected to the gas burner 2. The fuel gas and air are fully mixed in the gas burner 2 and then ignited. The initial combustion produces a high-temperature heat medium of 800-1000℃, which quickly preheats the furnace body 1 and the internal air distribution plate 17, gas chamber 19, bed material, etc. The temperature of the furnace body 1 is continuously monitored. When the temperature rises to 400-800℃ (above the ignition point of the fuel gas), the preheating is completed, and the temperature of the furnace body 1 is kept stable in this range.

[0057] Combustion gas supply stage: First, the first combustion-supporting gas unit 3 is turned on, and a uniformly mixed gas of oxygen and carbon dioxide, prepared according to a preset ratio, is fed into the gas burner 2 via a branch connected to the gas burner 2. Simultaneously, the fuel gas supply from the fuel gas unit 4 to the gas burner 2 is turned off, and the supply of fuel gas is switched to the branch connecting the fuel gas unit 4 to the second air inlet 13 of the furnace body 1. At this time, the gas burner 2 acts as a conduit, guiding the mixed gas into the gas chamber 19 of the furnace body 1, and then uniformly spraying it into the furnace 11 through the fluidizing nozzles 18 on the air distribution plate 17, where it mixes and burns with the fuel gas. During this process, the air supply valve of the second combustion-supporting gas unit 5 is gradually closed, stopping the air supply and ensuring that the combustion-supporting gas is switched from air to a mixed gas, avoiding sudden changes in oxygen concentration in the furnace 11 that could lead to unstable combustion. During combustion, the back pressure of the furnace body 1 is adjusted in real time via the pressure regulating valve 16, in conjunction with the pressure control of each gas unit, to maintain the pressure in the furnace 11 at the target value. Simultaneously, the temperature distribution in the furnace 11 is monitored, and the supply flow rates of the fuel gas and the mixed gas are adjusted to ensure continuous and stable combustion. To provide a uniform and stable thermal environment for the heat transfer probes in the dense phase, splash, and dilute phase regions during the heat transfer parameter experiment of furnace body 1, ensuring the accuracy of the experimental data. Throughout the process, the oxygen volume ratio of the mixed gas remains constant. If adjustment is required, the input ratio of oxygen and carbon dioxide can be adjusted in real time through the mixing tank of the first combustion-supporting unit 3.

[0058] Furthermore, the boiler gas supply method of this invention can also be adapted to the pressurized oxygen-enriched combustion requirements of solid fuels (coal particles, coal powder). Once the combustion of the gaseous fuel and the mixed gas is stable and the pressure in the furnace 11 reaches the target value, a separate coal supply system (such as a separately set feeder, raw material bin, pressurization bin, etc.) is activated: For coal-fired fluidized bed operation, coal particles of appropriate size are fed into the furnace 11 through the feeder, while the gaseous fuel supply is gradually reduced and the mixed gas supply of the first combustion-supporting unit 3 is adjusted. One path of the mixed gas fed into the furnace through the air distribution plate 17 and the fluidizing nozzle 18 must meet the fluidization requirements of the bed material and coal particles, while the other path of the mixed gas fed into the furnace through the third air inlet 14 supplements the combustion support until the coal particles completely replace the gaseous fuel, maintaining a stable fluidized combustion state in the furnace 11; For pulverized coal combustion operation, pulverized coal is continuously fed into the furnace 11 through the coal supply system, while the gaseous fuel supply is reduced simultaneously and the total mixed gas supply is adjusted to ensure that the pulverized coal and the mixed gas are in full contact and completely combusted, avoiding excessive local temperature or excessive nitrogen oxides.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0064] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A boiler gas supply system, characterized in that, include: Furnace body (1); A gas burner (2) is connected to the furnace body (1); The first gas-supporting unit (3) is connected to the furnace body (1) and the gas burner (2) and is used to supply a mixture of oxygen and carbon dioxide to at least one of the furnace body (1) and the gas burner (2); Fuel gas unit (4), which is connected to the furnace body (1) and the gas burner (2) for supplying fuel gas to at least one of the furnace body (1) and the gas burner (2); When the first combustion-supporting unit (3) and the fuel gas unit (4) simultaneously supply gas to the gas burner (2), the fuel gas and the mixed gas can burn in the gas burner (2), and the heat medium generated by combustion enters the furnace body (1) to heat the furnace body (1). When the fuel gas unit (4) only supplies gas to the furnace body (1), the gas burner (2) can serve as a channel to supply the mixed gas flowing through it into the furnace body (1), and the fuel gas and the mixed gas can burn in the furnace body (1).

2. The boiler gas supply system according to claim 1, characterized in that, It also includes a second gas-supporting unit (5), which is connected to the gas burner (2) and is used to supply air to the gas burner (2).

3. The boiler gas supply system according to claim 2, characterized in that, It also includes a protective gas unit (6) for supplying protective gas to the gas burner (2).

4. The boiler gas supply system according to claim 3, characterized in that, The first gas-supporting unit (3), the second gas-supporting unit (5), the fuel gas unit (4) and the protective gas unit (6) supply the same pressure of the gas medium, and the pressure range is 0-1.6MPa.

5. The boiler gas supply system according to claim 1, characterized in that, The furnace body (1) includes a furnace chamber (11), and a first air inlet (12), a second air inlet (13) and a third air inlet (14) connected to the furnace chamber (11). The first air inlet (12) is connected to the outlet of the gas burner (2); The fuel gas unit (4) is divided into two parallel paths, one of which is connected to the second air inlet (13), and the other is connected to the inlet of the gas burner (2); The first gas-supporting unit (3) is divided into two parallel paths, one of which is connected to the third air inlet (14), and the other is connected to the inlet of the gas burner (2).

6. The boiler gas supply system according to claim 5, characterized in that, The first air inlet (12) and the second air inlet (13) are located in the bottom region of the furnace body (1); and / or, The third air inlet (14) is located in the middle region of the furnace body (1).

7. The boiler gas supply system according to claim 1, characterized in that, The furnace body (1) also includes a flue (15), on which a pressure regulating valve (16) is provided, which is used to regulate the back pressure of the furnace body (1).

8. The boiler gas supply system according to claim 3, characterized in that, The fuel gas includes at least one of dimethyl ether, natural gas, methane, and propane; and / or, The protective gas is at least one of nitrogen, argon, and helium.

9. A boiler gas supply method, characterized in that, Implemented using the boiler gas supply system according to any one of claims 1-8, comprising: Preheating gas supply stage: The first combustion-supporting gas unit (3) and the fuel gas unit (4) respectively supply the mixed gas and the fuel gas to the gas burner (2) so that the fuel gas and the mixed gas burn in the gas burner (2) and preheat the furnace body (1) until the furnace body (1) reaches the preheating temperature, and then the fuel gas unit (4) stops supplying the fuel gas to the gas burner (2); Combustion gas supply stage: The fuel gas unit (4) supplies the fuel gas to the furnace body (1), and the first combustion-supporting unit (3) supplies the mixed gas to the furnace body (1) via the gas burner (2) so that the fuel gas and the mixed gas can be stably combusted in the furnace body (1); The volume percentage of oxygen in the mixed gas is 15%-30%.

10. The boiler gas supply method according to claim 9, characterized in that, During the preheating gas supply stage, the first gas-supporting unit (3) is replaced by the second gas-supporting unit (5) so that the fuel gas and the air are burned in the gas burner (2) and the furnace body (1) is preheated until the furnace body (1) reaches the preheating temperature. During the combustion gas supply phase, the air supply of the second combustion-supporting unit (5) is gradually stopped, and the mixed gas is supplied to the central region of the furnace (11) through the first combustion-supporting unit (3).

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