A gas turbine secondary air system and method utilizing carbon dioxide capture gas

Abstract

A kind of gas turbine secondary air system and method using carbon dioxide capture gas, as follows: air and flue gas from waste heat boiler are mixed and sent into compressor for compression, high-pressure gas enters combustion chamber and mixes with fuel, then burns to produce high-temperature and high-pressure gas, which then enters gas turbine to expand and do work, driving generator a to generate electricity, after gas turbine does work, flue gas enters waste heat boiler, which uses waste heat to generate steam for driving generator b to do work and generate electricity, part of flue gas after releasing heat is mixed with air from environment by recirculation fan and then re-enters compressor, another part is sent to carbon dioxide capture device for capture, captured carbon dioxide is sent to gas tank group for use as cooling gas, and captured flue gas is clean and discharged empty.The present application uses secondary air system supplied by independent carbon dioxide compressed gas, which ensures thermal protection of high-temperature components of gas turbine during startup and variable working condition, and can improve the safety of unit while efficiently enriching and utilizing carbon dioxide.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and more specifically to a gas turbine secondary air system and method that utilizes carbon dioxide capture gas. Background Technology

[0002] As the Brayton cycle demonstrates, improving gas turbine efficiency inevitably leads to an increase in the gas turbine inlet temperature. The hot-end components of a gas turbine bear unevenly distributed heat loads. While some progress has been made in high-temperature resistant materials, it is still far from sufficient to withstand the inlet temperatures of modern gas turbines. Developing advanced cooling technologies is a crucial measure for protecting hot-end components. Common thermal protection measures can be categorized by their location into internal protection (impact cooling, convection cooling, etc.) and external protection (film cooling, thermal barrier coatings, etc.), with film cooling being a critical thermal protection measure. Low-temperature air is blown out from the blade surface, and under the pressure of the main flow, the cold air covers the surface of the hot-end components, forming a film layer to prevent erosion by the high-temperature combustion gases. Therefore, gas turbines are equipped with a secondary air system.

[0003] Traditional secondary air systems draw cooling gas from different compressor stages, sending it through a series of components such as extraction channels, pipelines, and nozzles to the corresponding turbine stages for cooling. This process increases the complexity of the gas turbine's air path design. Furthermore, under varying operating conditions, compressor extraction is detrimental to stable operation, and insufficient cooling gas supply to hot-end components can lead to reduced lifespan or even burnout. Based on these reasons, the independent secondary air system proposed in this invention enables precise control of high-temperature component cooling under various operating modes, reduces the compressor load and the complexity of air path design, improves the safety of hot-end components, and broadens the operating conditions of the unit.

[0004] Furthermore, the consumption of fossil fuels is a major source of carbon dioxide, and the year-on-year increase in carbon dioxide concentration is a major cause of the greenhouse effect. Carbon capture, utilization, and storage (CCUS) technology is a means of mitigating global warming; however, how to utilize carbon dioxide is a challenge in CCUS technology. This invention captures carbon dioxide from the flue gas emitted in the combined cycle and uses it as a gas source for cooling the gas turbine. Summary of the Invention

[0005] Technical problems to be solved: In existing technologies, the cooling gas for secondary air systems in gas turbines is drawn from different stages of the compressor and delivered to the corresponding turbine stages through a series of flow elements. This process increases the complexity of the gas turbine's gas path design and introduces numerous risks under varying operating conditions. Furthermore, the gas turbine combustion chamber consumes fossil fuels and produces large amounts of carbon dioxide, and the efficient utilization of carbon dioxide is a challenge for CCUS (Carbon Dioxide Capture and Retrieval System) technology. This invention proposes a secondary air system and method for gas turbines that utilizes carbon dioxide capture gas. The system employs an independent secondary air supply from a gas storage tank (containing compressed carbon dioxide), ensuring thermal protection of high-end components of the gas turbine during startup and under varying operating conditions. This improves the safety of the unit while efficiently enriching and utilizing carbon dioxide.

[0006] Technical solution: A secondary air system for a gas turbine utilizing carbon dioxide capture gas, comprising air, fuel gas, compressor, combustion chamber, fuel gas turbine, waste heat boiler, steam turbine, recirculation fan, carbon dioxide capture device, gas tank group, and generators a and b.

[0007] The compressor, gas turbine, and generator a are mounted on the same shaft, and the steam turbine and generator b are mounted on the same shaft.

[0008] The air is connected to the compressor inlet pipe, and the compressor outlet is connected to the combustion chamber inlet pipe.

[0009] The gas is connected to the fuel inlet pipe of the combustion chamber, and the gas outlet of the combustion chamber is connected to the gas inlet pipe of the gas turbine.

[0010] The gas turbine (3) is connected to the generator a to drive the generator a to generate electricity. The gas turbine cooling gas inlet is connected to the gas tank group gas outlet pipeline, and the gas turbine flue gas outlet is connected to one of the gas inlets of the waste heat boiler.

[0011] The waste heat boiler has two flue gas outlets. One flue gas outlet is divided into two paths. One path is connected to the pipeline between the recirculation fan and the air compressor inlet. The other path is connected to the inlet pipeline of the carbon dioxide capture device. The steam turbine is connected to generator b to drive generator b to generate electricity. The steam turbine outlet is connected to another air inlet of the waste heat boiler.

[0012] The carbon dioxide capture device is used to capture carbon dioxide. The carbon dioxide outlet is connected to the inlet pipe of the gas tank group, and the captured flue gas is discharged into the air through the outlet.

[0013] Preferably, the gas turbine includes three turbine stages: a turbine first stage, a turbine second stage, and a turbine last stage. The gas tank group includes a gas storage tank and a cooling gas tank group, which are connected. The cooling gas tank group includes a high-pressure gas tank, a medium-pressure gas tank, and a low-pressure gas tank. The side outlet of the high-pressure gas tank is connected to the cold air inlet pipe of the turbine first stage, the side outlet of the medium-pressure gas tank is connected to the cold air inlet pipe of the turbine second stage, and the side outlet of the low-pressure gas tank is connected to the cold air inlet pipe of the turbine last stage.

[0014] Preferably, the gas tank assembly further includes a carbon dioxide gas compressor. Pressure gauges are provided for the high-pressure, medium-pressure, and low-pressure gas tanks to control the pressure in each tank in real time, ensuring that each tank is neither under-pressure nor over-pressured. One inlet of the carbon dioxide gas compressor is connected to the outlet of the storage tank, and the other outlet is connected to the inlet pipe of the high-pressure tank, or simultaneously to the inlet pipes of the high-pressure, medium-pressure, and low-pressure tanks. When the other outlet of the carbon dioxide gas compressor is connected to the inlet pipe of the high-pressure tank, pressure valves a and b are provided between the high-pressure, medium-pressure, and low-pressure tanks, and the high-pressure, medium-pressure, and low-pressure tanks are connected sequentially by pipes. When simultaneously connected to the inlet pipes of the high-pressure, medium-pressure, and low-pressure tanks, the high-pressure, medium-pressure, and low-pressure tanks do not contact each other. Pressure distribution strategy for the gas tank group: 1. The carbon dioxide gas compressor delivers high-pressure carbon dioxide to the high-pressure gas tank. At this time, the pressure valves between the tanks are fully open. When the low-pressure gas tank reaches the rated pressure, pressure valve b is closed. When the medium-pressure gas tank reaches the rated pressure, pressure valve a is closed. Finally, the required pressure for the high-pressure gas tank is achieved. When the unit is running and secondary air cooling is required, the pressure is dynamically balanced by adjusting the valve opening. 2. The carbon dioxide gas compressor outputs three pressure levels of gas to the high-pressure gas tank, medium-pressure gas tank, and low-pressure gas tank.

[0015] Preferably, the high-pressure gas tank, medium-pressure gas tank, and low-pressure gas tank are single tanks or tank groups of the same pressure, and the carbon dioxide gas compressor is a gas compressor whose main function is to pressurize the carbon dioxide in the storage tank to the required pressure.

[0016] Preferably, the carbon dioxide capture device is used to filter flue gas and capture carbon dioxide, including a flue gas absorption unit and a solution regeneration unit. The flue gas absorption unit includes a primary filtration unit, a secondary filtration unit, a tertiary filtration unit, a carbon dioxide capture chamber, and a tail gas chamber connected in sequence. The top of the carbon dioxide capture chamber is equipped with an absorbent liquid control unit, which is a spray device with an opening at the middle of the bottom. The solution regeneration unit is a regeneration tower with a heat exchange coil inside. The regeneration tower has a hot flue gas inlet on one side and a cold flue gas outlet on the other side. The top is equipped with an enriched liquid inlet, the bottom is equipped with a concentrated carbon dioxide absorbent liquid outlet, and the top is equipped with a carbon dioxide outlet. The hot flue gas inlet is the inlet of the heat exchange coil, and the cold flue gas outlet is the outlet of the heat exchange coil. The cold flue gas outlet is connected to the pipeline of the primary filtration unit. The enriched liquid inlet is connected to the pipeline at the bottom opening of the carbon dioxide capture chamber. The absorbent liquid outlet is connected to the inlet pipeline of the spray device at the top of the carbon dioxide capture chamber. The carbon dioxide outlet is connected to the inlet pipeline of the gas tank group. The absorbent liquid is a carbon dioxide absorption solution, and the enriched liquid is an absorbent liquid that has absorbed carbon dioxide.

[0017] Preferably, the primary filtration unit is a pretreatment unit used to remove larger particles; the secondary filtration unit is a filter media unit, which can be made of materials such as cellulose, polyester fiber, and glass fiber, and has high surface area and porosity, used to capture and adsorb fine particles and pollutants in flue gas; and the tertiary filtration unit is a pressure stabilizing unit used to control the flow rate and pressure of flue gas entering the carbon dioxide capture chamber.

[0018] Preferably, the regeneration tower includes a solution pump located upstream of the pipe connecting the absorbent outlet to the inlet of the spray device at the top of the carbon dioxide capture chamber.

[0019] Preferably, the flue gas absorption unit also includes a carbon dioxide concentration sensor, which is located on one side of the bottom of the carbon dioxide collection chamber. The carbon dioxide concentration sensor adjusts the amount of absorbent spray in real time according to the carbon dioxide concentration in the flue gas to ensure the carbon dioxide decarbonization efficiency. Generally speaking, carbon dioxide is used as a secondary air source. During operation, the concentration of carbon dioxide in the incoming flue gas increases, and the spraying volume increases.

[0020] Preferably, the regeneration tower includes heat exchanger a and heat exchanger b, which are shell-and-tube heat exchangers, with the hot flue gas flowing through the tubes.

[0021] Preferably, the high-pressure gas tank and the carbon dioxide gas compressor are wrapped with a water jacket to absorb the heat of compression and use the heat as a heat source for the heat exchanger.

[0022] Preferably, the high-pressure gas tank is connected to a generator, which can convert the potential energy of compressed air into electrical energy while ensuring sufficient cooling.

[0023] Based on the above-mentioned operation method of a gas turbine secondary air system utilizing carbon dioxide capture gas, the steps are as follows: air and flue gas from the waste heat boiler are mixed and sent to the compressor for compression. The high-pressure gas enters the combustion chamber and mixes with fuel to produce high-temperature and high-pressure gas. The high-temperature and high-pressure gas enters the gas turbine for expansion and does work, driving generator a to generate electricity. After the gas turbine does work, the flue gas enters the waste heat boiler. The waste heat boiler uses the residual heat in the flue gas after it has done work, i.e., the high-temperature exhaust gas (gas turbine tail gas), to generate steam to drive generator b to do work and generate electricity. The flue gas that has released its heat is divided into two paths. One part of the flue gas is mixed with the ambient air through the recirculation fan and then re-enters the compressor. The remaining flue gas is sent to the carbon dioxide capture device for carbon dioxide capture. After capture, the carbon dioxide is sent to the gas tank group as cooling gas. After capture, the flue gas is cleanly discharged into the atmosphere.

[0024] The operating principle of this invention is as follows: the primary air flow path is between the compressor and the combustion chamber, and the secondary air flow path is between the gas tank assembly and the gas turbine. The primary and secondary air are mixed in the gas turbine. The gas in the gas tank assembly is carbon dioxide, which provides corresponding pressure cold air to the demand side of each stage of the gas turbine. The cooled carbon dioxide enters the waste heat boiler with the high-temperature mainstream to release heat. The flue gas after releasing heat enters the carbon dioxide capture device, and the captured carbon dioxide enters the gas tank assembly.

[0025] The aforementioned carbon dioxide capture device includes a spray system at the top of the carbon dioxide capture chamber. The sprayed absorbent comes into contact with the incoming flue gas to enrich the carbon dioxide, transforming the concentrated absorbent into a dilute absorbent. After absorbing carbon dioxide, the absorbent's concentration decreases, requiring regeneration in a solution regeneration unit. The regeneration tower heats the absorbent to reduce carbon dioxide solubility, drawing heat from the high-temperature flue gas entering the absorption unit and the heat of compression of the carbon dioxide, achieving efficient utilization of internal energy and other quality parameters. After the absorbent releases carbon dioxide, it becomes a concentrated absorbent. A solution pump then pumps the concentrated absorbent into the flue gas absorption unit, while the carbon dioxide enters the gas tank assembly.

[0026] Beneficial effects: As described above, the present invention has the following effects:

[0027] 1. Traditional gas turbine secondary air systems draw air from different compressor stages and deliver it to the corresponding turbine stages for cooling through a series of components such as extraction tanks, pipelines, and nozzles. During unit startup, before the unit reaches rated operating conditions, the cold air (low pressure and small flow rate) provided by the compressor cannot meet the turbine's cooling requirements. Furthermore, the extraction of gas affects the safe operation of the compressor. The temperature at the combustion chamber outlet, i.e., the turbine inlet, rises rapidly and urgently needs cooling. Insufficient cold air supply to hot-end components leads to reduced lifespan or even burnout. In contrast, this invention forms an independent airflow path for the cooling gas, using three pressure-stage gas tanks connected to the corresponding turbine stages to be cooled. The compressed gas stored in the three pressure-stage gas tanks can provide a sufficient air source at any time, unaffected by unit startup, ensuring the safe operation of the unit, thereby improving the safety of hot-end components and expanding the unit's operating conditions.

[0028] 2. In traditional gas turbine secondary air systems, when the unit changes operating conditions, the parameters of the cooling air supplied by the compressor fluctuate, and the turbine inlet temperature does not change immediately. Therefore, there is a mismatch between demand and supply. However, in this invention, by controlling the opening of the storage valves of the three pressure-stage gas tanks, the cooling air demand of the turbine can be quickly matched, and precise control of the cooling of high-temperature components under various operating modes can be achieved.

[0029] 3. Carbon dioxide emissions are increasing year by year, and the greenhouse effect is constantly worsening. Countries are constantly developing advanced CCUS technology, but the utilization of carbon dioxide is a difficult problem. This invention not only captures carbon dioxide from the unit, but also uses the captured carbon dioxide as a gas source for the secondary air system. In addition, the increase in carbon dioxide concentration in the flue gas is conducive to the capture of carbon dioxide and improves the absorption efficiency of the absorbent.

[0030] 4. During peak electricity consumption periods, under the premise of ensuring turbine cooling, the gas in the high-pressure gas tank does work to drive the generator to generate electricity for the power plant's internal power consumption, thereby improving the economic efficiency of unit operation;

[0031] 5. In addition, the cooling gas drawn from the gas tank assembly in this invention is lower in temperature than the gas drawn directly from the compressor in the conventional method, and requires less cooling capacity under the same working fluid conditions. Furthermore, under the high pressure conditions inside the gas tank assembly, the interaction between molecules is enhanced, the carbon dioxide diffusion capacity is strong, and the thermal protection capability is better than that of the air drawn from the compressor in the conventional method. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a gas turbine secondary air system utilizing carbon dioxide capture gas according to the present invention;

[0033] Figure 2 This is a schematic diagram of the carbon dioxide capture device in the flue gas emitted by the gas-steam combined cycle of the present invention;

[0034] Figure 3This is a schematic diagram of the pressurization and storage of captured carbon dioxide in this invention. In the figure, (a) is a schematic diagram of the connection between the outlet of the carbon dioxide gas compressor and the inlet pipe on one side of the high-pressure gas tank, and (b) is a schematic diagram of the connection between the outlet of the carbon dioxide gas compressor and the inlet pipes on one side of the high-pressure gas tank, the medium-pressure gas tank and the low-pressure gas tank.

[0035] Figure 4 This is a schematic diagram of the carbon dioxide circulation in the secondary air system of the gas turbine of the present invention;

[0036] Figure 5 This is a schematic diagram of the flow of mainstream gas during the operation of the gas turbine secondary air system of the present invention;

[0037] Figure 6 This is a functional schematic diagram of the high-pressure gas tank assembly of the present invention;

[0038] The numbers in the diagram represent the following: 1. Compressor; 2. Combustion chamber; 3. Gas turbine; 4. Waste heat boiler; 5. Steam turbine; 6. Recirculation fan; 7. Carbon dioxide capture device; 7-1. Flue gas absorption unit; 7-1-1. Primary filtration unit; 7-1-2. Secondary filtration unit; 7-1-3. Tertiary filtration unit; 7-1-4. Carbon dioxide capture chamber; 7-1-5. Exhaust gas chamber; 7-1-6. Absorbent liquid control unit; 7-1-7. Carbon dioxide concentration sensor; 7-2. Solution regeneration unit; 7-2-1. Heat exchanger a; 7-2-2. Heat exchanger b; 7-2-3. Solution pump; 8. Gas tank group; 8-0. Carbon dioxide gas compressor; 8-1. Gas storage tank; 8-2. High-pressure gas tank; 8-3. Medium-pressure gas tank; 8-3-1. Pressure valve a; 8-4. Low-pressure gas tank; 8-4-1. Pressure valve b; G1. Generator a; G2. Generator b. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The specific embodiments are only one technical means to implement the present invention and should not be construed as limiting the technical solution of the present invention.

[0040] Currently widely used gas-steam combined cycle units (not limited to the following two examples):

[0041] 1.GE 9HA.01 Combined Cycle Power Plant:

[0042] Gas turbine: GE 9HA.01 gas turbine

[0043] Steam turbine: A common type of steam turbine (e.g., a triple-expansion steam turbine).

[0044] Flue gas temperature range from gas turbine exhaust: 550℃ to 600℃

[0045] The temperature range of the flue gas discharged from the waste heat boiler is approximately 150℃.

[0046] 2.Siemens SGT-800 Combined Cycle Power Plant:

[0047] Gas turbine: Siemens SGT-800 gas turbine

[0048] Steam turbine: A common type of steam turbine (e.g., a double-expansion steam turbine).

[0049] Flue gas temperature range from gas turbine exhaust: 500℃ to 550℃

[0050] The temperature range of the flue gas discharged from the waste heat boiler is approximately 120℃.

[0051] The temperature of the flue gas discharged from the other heat boilers meets the requirements of the heat exchangers 7-2-1 and 7-2-2 in the regeneration tower of the carbon dioxide capture device 7.

[0052] Example 1

[0053] A gas turbine secondary air system utilizing carbon dioxide capture gas, see [link to relevant documentation]. Figure 1 It includes air, gas, compressor 1, combustion chamber 2, gas turbine 3, waste heat boiler 4, steam turbine 5, recirculation fan 6, carbon dioxide capture device 7, gas tank group 8, and generator a G1 and generator b G2.

[0054] The compressor 1, gas turbine 3, and generator a G1 are mounted on the same shaft, and the steam turbine 5 and generator b G2 are mounted on the same shaft.

[0055] Air is connected to the air inlet pipe of compressor 1, and air outlet of compressor 1 is connected to the air inlet pipe of combustion chamber 2.

[0056] The gas is connected to the fuel inlet pipe of combustion chamber 2, and the gas outlet of combustion chamber 2 is connected to the gas inlet pipe of gas turbine 3.

[0057] The gas turbine 3 is connected to the generator a G1 to drive the generator a G1 to generate electricity. The cooling gas inlet of the gas turbine 3 is connected to the gas outlet pipeline of the gas tank group 8. The flue gas outlet of the gas turbine 3 is connected to one air inlet of the waste heat boiler 4.

[0058] Waste heat boiler 4 has two flue gas outlets. One outlet is connected to the air inlet of air compressor 1 via a recirculation fan 6, and the other outlet is connected to the air inlet of carbon dioxide capture device 7. Steam turbine 5 is connected to generator bG2 to drive generator bG2 to generate electricity. The outlet of steam turbine 5 is connected to another air inlet of waste heat boiler 4.

[0059] The carbon dioxide capture device 7 has its carbon dioxide outlet connected to the gas tank group 8's inlet pipe, and the captured flue gas is discharged into the air through the outlet.

[0060] Based on the above-mentioned method for using a gas turbine secondary air system to perform work using carbon dioxide capture gas, the steps are as follows: Air and flue gas from the waste heat boiler 4 are mixed and sent to the compressor for compression. The high-pressure gas enters the combustion chamber 2 and mixes with fuel to produce high-temperature and high-pressure gas. The high-temperature and high-pressure gas enters the gas turbine 3 to expand and perform work, driving generator a G1 to generate electricity. After the gas turbine 3 performs work, the flue gas enters the waste heat boiler 4. The waste heat boiler 4 uses the residual heat in the flue gas after it has performed work to generate steam, which is used to drive generator b G2 to perform work and generate electricity. The flue gas that has released its heat is divided into two paths. One part of the flue gas is mixed with the ambient air through the recirculation fan 6 and then re-enters the compressor 1. The remaining flue gas is sent to the carbon dioxide capture device 7 for carbon dioxide capture. After capture, the carbon dioxide is sent to the gas tank group 8 as cooling gas. After capture, the flue gas is cleanly discharged into the atmosphere.

[0061] Example 2

[0062] Similar to Embodiment 1, the difference is that the gas turbine 3 includes three turbine stages, namely the turbine first stage, the turbine second stage, and the turbine last stage. The gas tank group 8 includes a gas storage tank 8-1 and a cooling gas tank group. The gas storage tank 8-1 is connected to the cooling gas tank group. The cooling gas tank group includes a high-pressure gas tank 8-2, a medium-pressure gas tank 8-3, and a low-pressure gas tank 8-4. The side outlet of the high-pressure gas tank 8-2 is connected to the cold air inlet pipe of the turbine first stage. The side outlet of the medium-pressure gas tank 8-3 is connected to the cold air inlet pipe of the turbine second stage. The side outlet of the low-pressure gas tank 8-4 is connected to the cold air inlet pipe of the turbine last stage.

[0063] The gas tank assembly 8 also includes a carbon dioxide gas compressor 8-0. High-pressure gas tank 8-2, medium-pressure gas tank 8-3, and low-pressure gas tank 8-4 are equipped with pressure gauges to control the pressure in each gas tank in real time, ensuring that each gas tank is neither under-pressure nor over-pressured. The pressure in high-pressure gas tank 8-2, medium-pressure gas tank 8-3, and low-pressure gas tank 8-4 is set according to the pressure required for the corresponding turbine stage. (See [link to relevant documentation]). Figure 3(a) The inlet of the carbon dioxide gas compressor 8-0 is connected to the outlet of the gas storage tank 8-1 on one side, and the outlet on the other side is connected to the inlet of the high-pressure gas tank 8-2 on one side. Pressure valves a 8-3-1 and b 8-4-1 are installed between the high-pressure gas tank 8-2, the medium-pressure gas tank 8-3, and the low-pressure gas tank 8-4. The high-pressure gas tank 8-2, the medium-pressure gas tank 8-3, and the low-pressure gas tank 8-4 are connected in sequence by pipelines. The carbon dioxide gas compressor 8-0 delivers high-pressure carbon dioxide to the gas tank group. At this time, the pressure valves between the tanks are fully open. When the low-pressure gas tank 8-4 reaches the rated pressure, valve 8-4-1 is closed. When the medium-pressure gas tank 8-3 reaches the rated pressure, valve 8-3-1 is closed. Finally, the required pressure of the high-pressure gas tank is achieved. When the unit needs secondary air cooling during operation, the pressure is dynamically balanced by dynamically adjusting the valve opening.

[0064] The high-pressure gas tank 8-2, medium-pressure gas tank 8-3 and low-pressure gas tank 8-4 are single tanks or tank groups of the same pressure. The carbon dioxide gas compressor 8-0 is a gas compressor, whose main function is to pressurize the carbon dioxide in the gas storage tank 8-1 to the required pressure.

[0065] The carbon dioxide capture device 7 is used to filter the flue gas and capture carbon dioxide. See [link to documentation]. Figure 2 The system includes a flue gas absorption unit 7-1 and a solution regeneration unit 7-2. The flue gas absorption unit 7-1 comprises a primary filtration unit 7-1-1, a secondary filtration unit 7-1-2, a tertiary filtration unit 7-1-3, a carbon dioxide capture chamber 7-1-4, and an exhaust gas chamber 7-1-5 connected in sequence. The carbon dioxide capture chamber 7-1-4 has an absorbent liquid control unit 7-1-6 at its top, which is a spray device with an opening at the center of its bottom. The solution regeneration unit 7-2 is a regeneration tower containing heat exchange coils. The regeneration tower has a hot flue gas inlet (approximately 130°C) on one side and a cold flue gas outlet on the other. It also has a enriched liquid inlet at the top and a concentrated carbon dioxide absorbent liquid outlet at the bottom. The chamber is equipped with a carbon dioxide outlet at one end, a hot flue gas inlet (which is also the inlet of the heat exchange coil), and a cold flue gas outlet (which is also the outlet of the heat exchange coil). The cold flue gas outlet is connected to the primary filter unit 7-1-1 via a pipe. The enrichment liquid inlet is connected to the bottom opening of the carbon dioxide capture chamber 7-1-4 via a pipe. The absorbent liquid outlet is connected to the inlet of the top spray device of the carbon dioxide capture chamber via a pipe. The carbon dioxide outlet is connected to the inlet of the gas tank group 8 via a pipe. The absorbent liquid is a carbon dioxide absorption solution (such as an amine solution: ethanolamine (MEA), diethanolamine (DEA), etc.), and the enrichment liquid is the absorbent liquid that has absorbed carbon dioxide. The absorbent liquid control unit 7-1-6 is used to store the absorbent liquid and adjust the absorbent liquid spray volume according to the concentration feedback from the carbon dioxide sensor 7-1-7. The absorbent liquid is injected into the carbon dioxide capture chamber 7-1-4 through the top spray device, where it comes into contact with the low-temperature flue gas (20°C to 60°C) entering it, undergoes a chemical reaction to generate compounds, and is then absorbed.

[0066] The primary filtration unit 7-1-1 is a pretreatment unit used to remove larger particulate matter such as dust and particulate pollutants from the flue gas. It includes a pre-dust collector, a desulfurization device, and a denitrification device. The pre-dust collector removes large particles, the desulfurization device removes sulfur dioxide, and the denitrification device reduces nitrogen oxide emissions. The secondary filtration unit 7-1-2 is a filter media unit, serving as an intermediate filtration unit for the flue gas. It can employ electrostatic precipitators, bag filters, or other filtration devices. The filter media can be made of materials such as cellulose, polyester fiber, and glass fiber, possessing high surface area and porosity, used to capture and adsorb fine particulate matter and pollutants in the flue gas. The tertiary filtration unit 7-1-3 is a pressure stabilization unit used to control the flow rate and pressure of the flue gas entering the carbon dioxide capture chamber 7-1-4, typically including a gas regulating valve, pressure sensor, and control system.

[0067] The regeneration tower includes a solution pump 7-2-3, which is located upstream of the pipeline connecting the absorbent outlet and the inlet of the spray device at the top of the carbon dioxide capture chamber.

[0068] The flue gas absorption unit 7-1 also includes a carbon dioxide concentration sensor 7-1-7, which is located on one side of the bottom of the carbon dioxide collection chamber 7-1-4.

[0069] The regeneration tower includes heat exchanger a 7-2-1 and heat exchanger b 7-2-2, which are shell-and-tube heat exchangers, with hot flue gas flowing through the tubes.

[0070] Example 3

[0071] Similar to Example 2, the difference is that in this example, when the gas turbine starts, the compressor 1 draws in air from the environment and compresses it in stages. The high-pressure compressed air enters the combustion chamber 2 and mixes with the fuel. The combustion process produces high-temperature and high-pressure gas. The high-temperature and high-pressure gas enters the gas turbine 3, expands and does work, driving the generator a G1 to generate electricity. After the gas turbine finishes its work, the flue gas enters the waste heat boiler 4. The waste heat boiler 4 has three outlets. Part of the flue gas is mixed with the air in the environment by the recirculation fan 6 and then re-enters the compressor 1. Part of the flue gas is sent to the carbon dioxide capture device 7. The last outlet is the high-temperature and high-pressure steam generated by the waste heat boiler, which enters the steam turbine 5. The steam turbine drives the generator b G2 to do work and generate electricity.

[0072] See Figure 2The carbon dioxide capture device 7 involves the flue gas passing through the regeneration tower of the solution regeneration unit 7-2 for heat exchange. After cooling, the flue gas enters the absorption unit 7-1. A spray device is installed at the top of the absorption unit, where the top absorbent liquid is sprayed into contact with the flue gas to complete carbon dioxide capture. The spraying rate can be adjusted according to the flue gas volume to ensure sufficient carbon dioxide absorption. The enriched absorbent liquid, having absorbed carbon dioxide, is fed into the regeneration tower. The regeneration tower heats the absorbent liquid to reduce the solubility of carbon dioxide. The heat source comes from the high-temperature flue gas and the compression heat of the compression device, achieving efficient utilization of internal energy and other quality parameters. After carbon dioxide is released from the absorbent liquid, it becomes concentrated absorbent liquid, which is pumped back to the flue gas absorption unit 7-1 via a melt pump. The carbon dioxide then enters the gas storage tank 8-1.

[0073] See Figure 3 (a) The inlet of gas storage tank 8-1 is connected to carbon dioxide capture device 7, and the outlet of gas storage tank 8-1 is connected to carbon dioxide gas compressor 8-0 via a pipeline; the high-pressure gas in the high-pressure tank is pressurized by carbon dioxide gas compressor 8-0. The device shaft can be connected to a variable frequency motor or the turbine shaft. Its purpose is to convert mechanical energy into the potential energy of carbon dioxide. The upper end of high-pressure tank 8-2 is connected to medium-pressure tank 8-3 via a pipeline. Pressure valve a 8-3-1 is installed above the pipeline. The right end of high-pressure tank 8-2 is connected to the first stage of gas turbine via a pipeline to provide high-pressure cold air; the upper end of medium-pressure tank 8-3 is connected to low-pressure tank 8-4 via a pipeline. Pressure valve b with pressure control is installed above the pipeline. 8-4-1, the right end of the medium-pressure gas tank 8-3 is connected to the second stage of the gas turbine via a pipeline to provide medium-pressure cooling air; the lower end of the low-pressure gas tank 8-4 is connected to the medium-pressure gas tank 8-3 via a pipeline, and the right end of the low-pressure gas tank 8-4 is connected to the final stage of the gas turbine via a pipeline to provide cooling air. Pressure control valves are installed on all connected pipelines to control the flow rate into each gas tank in real time and to monitor the inlet and outlet pressures, ensuring that each gas tank is neither under-pressurized nor over-pressurized.

[0074] See Figure 4 A schematic diagram of the carbon dioxide circulation in the secondary air system of a gas turbine. The gas tank group 8 provides cooling air to the first, second, and final stages of the gas turbine 3 for thermal protection of high-temperature components. After the secondary air and primary air are mixed, the secondary air is discharged from the gas turbine 3 and enters the waste heat boiler 4 to release waste heat. The flue gas enters the carbon dioxide capture device 7, first passes through a heat exchanger to reduce the temperature, and then enters the flue gas absorption unit 7-1. The absorbent liquid decomposes the carbon dioxide in the solution regeneration unit 7-2. The decomposed carbon dioxide is then transported to the gas tank group 8 through pipelines.

[0075] The arrangement of the secondary air path is not limited by the space and structure of the compressor, which reduces drag loss, does not cross the main airflow, and avoids heat exchange loss caused by the thermodynamic cycle process.

[0076] The flow rate and pressure of secondary air can be matched in real time according to the needs of the gas turbine.

[0077] See Figure 5 The schematic diagram of the main gas turbine shows that after the ambient air and high-temperature flue gas are mixed, they enter the compressor 1 and are pressurized in stages. The high-pressure gas at the outlet of the compressor 1 reacts with the fuel in the combustion chamber 2 to generate high-temperature and high-pressure gas, which enters the gas turbine 3 to do work. The flue gas discharged from the gas turbine unit enters the waste heat boiler 4. Part of the flue gas re-enters the compressor 1 through the recirculation fan 6, and part of the flue gas is sent to the carbon dioxide capture device 7. The flue gas entering the capture device 7 first passes through the heat exchanger 7-2-1 of the regeneration device to reduce the temperature, and then enters the flue gas absorption unit 7-1 to capture the carbon dioxide in the flue gas before being discharged.

[0078] Example 4

[0079] Same as Example 2, except that, see [link to Example 2] Figure 3 (b) The outlet of the carbon dioxide gas compressor 8-0 is simultaneously connected to the inlet pipes on one side of the high-pressure gas tank 8-2, the medium-pressure gas tank 8-3, and the low-pressure gas tank 8-4. The high-pressure gas tank 8-2, the medium-pressure gas tank 8-3, and the low-pressure gas tank 8-4 do not contact each other. The carbon dioxide gas compressor 8-0 outputs three pressure levels of gas to the high-pressure gas tank 8-2, the medium-pressure gas tank 8-3, and the low-pressure gas tank 8-4.

[0080] The high-pressure gas tank 8-2 and the carbon dioxide gas compressor 8-0 are wrapped with water jackets to absorb the heat of compression and use this heat as a supplementary heat source for heat exchangers 7-2-1 and 7-2-2.

[0081] The high-pressure gas tank 8-2 is connected to a generator, which can convert the potential energy of compressed air into electrical energy while ensuring sufficient cooling.

[0082] Example 5

[0083] Similar to Example 2, the difference lies in that the carbon dioxide gas compressor 8-0 is a reciprocating, screw, or scroll compressor, etc. Taking a screw compressor as an example, the compressor screw and the shaft of the combined cycle steam turbine driving the generator (G2) can be connected together using a differential gear, utilizing the shaft work of the turbine inside the combined cycle unit. The gas compressor can be driven by an external power source or by the shaft work of the combined cycle unit. During peak electricity consumption periods, provided that turbine cooling is ensured, the gas in the high-pressure gas tank performs work to drive the generator to generate electricity, improving the economic efficiency of the unit's operation. Figure 6 The carbon dioxide gas compressor 8-0 shown is a gas compressor. The arrow corresponding to the carbon dioxide gas compressor 8-0 represents the use of the shaft power of the combined unit to compress air. The opposite direction above indicates that the cooling air required by the unit is sufficient to drive the generator to do work and generate electricity, so it is represented by two opposite arrows.

Claims

1. A secondary air system for a gas turbine utilizing carbon dioxide capture gas, characterized in that, It includes air, gas, compressor (1), combustion chamber (2), gas turbine (3), waste heat boiler (4), steam turbine (5), recirculation fan (6), carbon dioxide capture device (7), gas tank group (8), and generator a (G1) and generator b (G2). The compressor (1), gas turbine (3) and generator a (G1) are mounted on the same shaft, and the steam turbine (5) and generator b (G2) are mounted on the same shaft. Air is connected to the air inlet pipe of the compressor (1), and the air outlet of the compressor (1) is connected to the air inlet pipe of the combustion chamber (2). The gas is connected to the fuel inlet pipe of the combustion chamber (2), and the gas outlet of the combustion chamber (2) is connected to the gas inlet pipe of the gas turbine (3); The gas turbine (3) is connected to the generator a (G1) to drive the generator a (G1) to generate electricity. The cooling gas inlet of the gas turbine (3) is connected to the gas outlet pipeline of the gas tank group (8). The flue gas outlet of the gas turbine (3) is connected to one air inlet of the waste heat boiler (4). The waste heat boiler (4) has two flue gas outlets. One flue gas outlet is divided into two paths. One path is connected to the air inlet of the air compressor (1) through the recirculation fan (6). The other path is connected to the air inlet of the carbon dioxide capture device (7). The other flue gas outlet is connected to the air inlet of the steam turbine (5). The steam turbine (5) is connected to the generator b (G2) to drive the generator b (G2) to generate electricity. The steam turbine (5) outlet is connected to the other air inlet of the waste heat boiler (4). The carbon dioxide outlet of the carbon dioxide capture device (7) is connected to the inlet pipe of the gas tank group (8), and the flue gas is discharged after capture. The gas turbine (3) includes three turbine stages, namely the turbine first stage, the turbine second stage and the turbine last stage. The gas tank group (8) includes a gas storage tank (8-1) and a cooling gas tank group. The gas storage tank (8-1) is connected to the cooling gas tank group. The cooling gas tank group includes a high-pressure gas tank (8-2), a medium-pressure gas tank (8-3) and a low-pressure gas tank (8-4). The side outlet of the high-pressure gas tank (8-2) is connected to the cold air inlet pipe of the turbine first stage. The side outlet of the medium-pressure gas tank (8-3) is connected to the cold air inlet pipe of the turbine second stage. The side outlet of the low-pressure gas tank (8-4) is connected to the cold air inlet pipe of the turbine last stage. The gas tank assembly (8) also includes a carbon dioxide gas compressor (8-0). High-pressure gas tank (8-2), medium-pressure gas tank (8-3), and low-pressure gas tank (8-4) are equipped with gas tank pressure gauges. One inlet of the carbon dioxide gas compressor (8-0) is connected to the outlet of the gas storage tank (8-1), and the other outlet is connected to the inlet pipe on one side of the high-pressure gas tank (8-2), or simultaneously connected to the inlet pipes on one side of the high-pressure gas tank (8-2), medium-pressure gas tank (8-3), and low-pressure gas tank (8-4). When the other outlet of the carbon dioxide gas compressor (8-0) is connected to the high-pressure gas tank… When the air inlet pipe on one side of the gas tank (8-2) is connected, pressure valve a (8-3-1) and pressure valve b (8-4-1) are installed between the high-pressure gas tank (8-2), the medium-pressure gas tank (8-3), and the low-pressure gas tank (8-4). The high-pressure gas tank (8-2), the medium-pressure gas tank (8-3), and the low-pressure gas tank (8-4) are connected to each other in sequence. When the air inlet pipe on one side of the high-pressure gas tank (8-2), the medium-pressure gas tank (8-3), and the low-pressure gas tank (8-4) are connected at the same time, the high-pressure gas tank (8-2), the medium-pressure gas tank (8-3), and the low-pressure gas tank (8-4) do not come into contact with each other.

2. A gas turbine secondary air system utilizing carbon dioxide capture gas according to claim 1, characterized in that, The high-pressure gas tank (8-2), medium-pressure gas tank (8-3), and low-pressure gas tank (8-4) are single tanks or tank groups of the same pressure. The carbon dioxide gas compressor (8-0) is a gas compressor whose main function is to pressurize the carbon dioxide in the gas storage tank (8-1) to the required pressure.

3. A gas turbine secondary air system utilizing carbon dioxide capture gas according to claim 1, characterized in that, The carbon dioxide capture device (7) is used to filter flue gas and capture carbon dioxide. It includes a flue gas absorption unit (7-1) and a solution regeneration unit (7-2). The flue gas absorption unit (7-1) includes a primary filtration unit (7-1-1), a secondary filtration unit (7-1-2), a tertiary filtration unit (7-1-3), a carbon dioxide capture chamber (7-1-4), and a tail gas chamber (7-1-5) connected in sequence. The top of the carbon dioxide capture chamber (7-1-4) is equipped with an absorbent liquid control unit (7-1-6), which is a spray device with an opening in the middle of the bottom. The solution regeneration unit (7-2) is a regeneration tower. The regeneration tower is equipped with a heat exchange coil. A hot flue gas inlet is located on one side of the regeneration tower, and a cold flue gas outlet is located on the other side. An enrichment liquid inlet is located at the top, a concentrated carbon dioxide absorbent liquid outlet is located at the bottom, and a carbon dioxide outlet is located at the top. The hot flue gas inlet is the inlet of the heat exchange coil, and the cold flue gas outlet is the outlet of the heat exchange coil. The cold flue gas outlet is connected to the pipeline of the primary filtration unit (7-1-1). The enrichment liquid inlet is connected to the bottom opening pipeline of the carbon dioxide capture chamber (7-1-4). The absorbent liquid outlet is connected to the inlet pipeline of the spray device at the top of the carbon dioxide capture chamber. The carbon dioxide outlet is connected to the inlet pipeline of the gas tank group (8). The absorbent liquid is a carbon dioxide absorbent solution, and the enrichment liquid is an absorbent liquid that has absorbed carbon dioxide.

4. A gas turbine secondary air system utilizing carbon dioxide capture gas according to claim 3, characterized in that, The primary filtration unit (7-1-1) is a pretreatment unit used to remove larger particles. The secondary filtration unit (7-1-2) is a filter media unit. The filter media is made of cellulose, polyester fiber, or glass fiber materials and has high surface area and porosity. It is used to capture and adsorb fine particles and pollutants in flue gas. The tertiary filtration unit (7-1-3) is a pressure stabilizing unit used to control the flow and pressure conditions of flue gas entering the carbon dioxide capture chamber (7-1-4).

5. A gas turbine secondary air system utilizing carbon dioxide capture gas according to claim 3, characterized in that, The regeneration tower includes a solution pump (7-2-3), which is located upstream of the pipeline connecting the absorbent outlet and the inlet of the spray device at the top of the carbon dioxide capture chamber.

6. A gas turbine secondary air system utilizing carbon dioxide capture gas according to claim 3, characterized in that, The flue gas absorption unit (7-1) also includes a carbon dioxide concentration sensor (7-1-7), which is located on one side of the bottom of the carbon dioxide collection chamber (7-1-4). The absorbent control unit (7-1-6) is used to store the absorbent and adjust the amount of absorbent sprayed according to the concentration feedback from the carbon dioxide sensor (7-1-7).

7. A gas turbine secondary air system utilizing carbon dioxide capture gas according to claim 3, characterized in that, The regeneration tower includes heat exchanger a (7-2-1) and heat exchanger b (7-2-2), which are shell-and-tube heat exchangers, with hot flue gas flowing through the tubes.

8. A method for operating a gas turbine secondary air system utilizing carbon dioxide capture gas, based on claim 1, characterized in that, The steps are as follows: After the air and flue gas from the waste heat boiler (4) are mixed, they are sent to the compressor (1) for compression. The high-pressure gas enters the combustion chamber (2) and is mixed with the fuel to generate high-temperature and high-pressure gas. The high-temperature and high-pressure gas enters the gas turbine (3) to expand and do work, driving the generator a (G1) to generate electricity. After the gas turbine (3) does work, the flue gas enters the waste heat boiler (4). The waste heat boiler (4) uses the residual heat in the flue gas after doing work to generate steam to drive the generator b (G2) to do work and generate electricity. The flue gas that has released heat is divided into two paths. One part of the flue gas is mixed with the air in the environment through the recirculation fan (6) and then re-enters the compressor (1). The remaining flue gas is sent to the carbon dioxide capture device (7) for carbon dioxide capture. After capture, the carbon dioxide is sent to the gas tank group (8) as cooling gas. After capture, the flue gas is cleanly discharged.

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