A flue gas split flue structure and a chemical looping combustion system

Abstract

A flue gas shunting flue structure and a chemical chain combustion system. The flue gas shunting flue structure comprises a first main flue, a first shunting flue, a supplementary combustion chamber, a first heat exchange device, a second main flue, a third shunting flue, a fourth shunting flue, a gas storage device and an oxygen supply device, the inlet of the first shunting flue is communicated with the first main flue, the outlet of the first shunting flue, the outlet of the third shunting flue, the inlet of the first heat exchange device and the outlet of the oxygen supply device are communicated with the supplementary combustion chamber, the outlet of the first heat exchange device is communicated with the inlet of the third shunting flue and the inlet of the fourth shunting flue, and the outlet of the third shunting flue is communicated with the inlet of the gas storage device; a second shunting flue, a second heat exchange device and a third main flue, the inlet of the second shunting flue is communicated with the first main flue, and the outlet of the second shunting flue, the second heat exchange device and the inlet of the third main flue are communicated. This scheme can reduce the oxygen supply amount of the oxygen supply device.

Description

Technical Field

[0001] This invention relates to the field of energy generation and environmental protection technology, and more specifically, to a flue gas diversion flue structure and a chemical looping combustion system. Background Technology

[0002] Chemical Looping Combustion (CLC) is a novel combustion technology that utilizes transition metal oxide particles in a fluidized bed reactor to circulate between two fluidized bed reactors, dividing the traditional direct combustion process into two steps. This technology avoids direct fuel contact with air and achieves CO2 separation and capture without additional energy consumption, making it one of the most promising CO2 capture technologies currently recognized.

[0003] CLC technology shares structural similarities with traditional fluidized bed boilers, both consisting of a boiler body and a tail flue. The tail flue is equipped with various heat exchangers and desulfurization / denitrification devices to recover heat from the flue gas and purify pollutants. However, the key difference between CLC technology and traditional fluidized bed boilers lies in the fact that the high-temperature flue gas discharged from the CLC equipment contains a certain volume concentration of unreacted combustible gases (including H2, CO, and CH4). To ensure the high purity of CO2 in the tail flue gas and meet the requirements for subsequent capture and utilization, an additional combustion chamber is often required in the tail flue to completely convert these unreacted combustible gases. Furthermore, the combustion gas must be high-purity oxygen, not air, to avoid introducing N2 to dilute the high-purity CO2 in the flue gas. This requirement significantly increases energy consumption and operating costs. Summary of the Invention

[0004] This invention provides a flue gas diversion type flue structure, including: a first main flue; a first diversion flue, a combustion chamber, a first heat exchange device, a second main flue, a third diversion flue, a fourth diversion flue, a gas storage device, and a pure oxygen supply device. The inlet of the first diversion flue is connected to the first main flue, and the outlets of the first diversion flue, the third diversion flue, the first heat exchange device, and the pure oxygen supply device are all connected to the combustion chamber. The outlet of the first heat exchange device is connected to the inlets of the third and fourth diversion flues, and the outlet of the third diversion flue is connected to the inlet of the gas storage device. The pure oxygen supply device is configured to controllably supply oxygen to the combustion chamber, and the gas storage device is configured to store purified flue gas. The second diversion flue, a second heat exchange device, and a third main flue are also included. The inlet of the second diversion flue is connected to the first main flue, and the outlets of the second diversion flue, the second heat exchange device, and the third main flue are sequentially connected.

[0005] In some exemplary embodiments, the flue gas diversion flue structure further includes: a first flue gas state detection device disposed in the first diversion flue, the first flue gas state detection device being configured to detect first state information of the flue gas; and a control device electrically connected to the first flue gas state detection device and the pure oxygen supply device, the control device being configured to determine, based on the first state information, data information of oxygen supplied by the pure oxygen supply device to the combustion chamber, and to control the pure oxygen supply device to supply oxygen to the combustion chamber according to the data information.

[0006] In some exemplary embodiments, the first state information includes the flue gas flow rate, the type of combustible gas in the flue gas, and the volume concentration of the combustible gas in the flue gas. The type of combustible gas includes H2, CO, and CH4. The data information includes the flow rate. The control device is configured to determine the flow rate of oxygen supplied by the pure oxygen supply device to the combustion chamber based on the first state information using the formula (x / 2+y / 2+2z)×q L / min, and to control the pure oxygen supply device to supply oxygen to the combustion chamber at the flow rate, where x is the H2 volume concentration, y is the CO volume concentration, z is the CH4 volume concentration, and q is the flue gas flow rate.

[0007] In some exemplary embodiments, the fourth diversion flue is provided with a second fan, and the flue gas diversion flue structure further includes: a temperature detection device disposed in the combustion chamber, the temperature detection device being configured to detect the actual temperature data of the combustion chamber; and a control device electrically connected to the second fan and the temperature detection device, the control device being configured to adjust the operating parameters of the second fan according to preset temperature data and the actual temperature data, so that the actual temperature data of the combustion chamber is adjusted to meet the preset temperature data.

[0008] In some exemplary embodiments, the operating parameters include at least one of voltage and current, and the preset temperature data ranges from 800°C to 900°C.

[0009] In some exemplary embodiments, the second main flue has a first fan and a first purification device, the first fan being located downstream of the first purification device, and the third main flue has a second purification device, a third fan, and a fourth fan arranged sequentially, the third fan and the fourth fan being located downstream of the second purification device.

[0010] In some exemplary embodiments, both the first purification device and the second purification device include a bag filter dust collector.

[0011] In some exemplary embodiments, the flue gas diversion flue structure further includes: a second flue state detection device, disposed in the second diversion flue, configured to detect second state information of the flue gas; and The third flue gas status detection device is located in the first main flue gas and is configured to detect the third status information of the flue gas.

[0012] In some exemplary embodiments, the first heat exchange device is a first heat exchange chamber, and the second heat exchange device is a second heat exchange chamber. Both the first heat exchange chamber and the second heat exchange chamber are equipped with a high-temperature economizer, a low-temperature economizer, and an air preheater. The gas storage device includes a compressor, a desulfurization bed, a drying bed, an adsorption bed, a refrigeration liquefaction unit, a distillation column, and a storage tank connected in sequence. The flue gas diversion flue structure also includes a desulfurization and denitrification device, which is located in the first heat exchange chamber.

[0013] This invention also provides a chemical looping combustion system, including a chemical looping combustion device and a flue gas diversion structure as described in any of the above embodiments. The chemical looping combustion device includes a fuel reactor, which has a recirculated flue gas inlet and a flue gas outlet. The inlet of the first main flue is connected to the flue gas outlet, and the outlet of the third main flue is connected to the recirculated flue gas inlet.

[0014] The technical solution provided in this invention involves a chemical loop combustion device where high-temperature flue gas discharged from the exhaust port enters the first main flue and is then diverted. A portion of the diverted flue gas flows through a first diversion flue to the combustion chamber. Based on the combustible gas content in the flue gas flowing from the first diversion flue to the combustion chamber, a pure oxygen supply device is controlled to supplement the combustion chamber with a corresponding amount of oxygen, ensuring that the combustible gas and oxygen in the combustion chamber react completely to produce water and carbon dioxide. The resulting flue gas is then cooled by a first heat exchanger before flowing into the second main flue. It is then diverted again through the second main flue. A portion of the diverted flue gas flows through a third diversion flue to the gas storage device, and the flue gas entering the gas storage device is purified flue gas, i.e., high-purity carbon dioxide. Another portion of the diverted flue gas flows back to the combustion chamber through a fourth diversion flue to cool the combustion chamber. To prevent localized overheating caused by the violent exothermic reaction between combustible gases and oxygen, another portion of the flue gas diverted from the first main flue passes through the second diversion flue, the second heat exchanger, and the third main flue. It then enters the fuel reactor through the recirculated flue gas inlet as fluidizing air, causing the fuel and oxygen carrier within the reactor to fluidize. The fuel undergoes pyrolysis within the reactor, producing combustible gases and coke. During this process, the combustible gases in the fluidizing air and those generated from fuel pyrolysis react with the oxidized oxygen carrier in the reactor, consuming the combustible gases and producing water, carbon dioxide, and reduced oxygen carrier. This second portion of the flue gas diverted from the first main flue is then reintroduced into the fuel reactor, where the oxidized oxygen carrier further removes the combustible gases, eliminating the need for a pure oxygen supply system. This design effectively reduces the amount of oxygen supplied by a pure oxygen supply system while ensuring stable storage of high-purity carbon dioxide, resulting in lower operating costs for the diversion flue structure.

[0015] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description and the drawings. Attached Figure Description

[0016] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0017] Figure 1 This application provides schematic block diagrams of flue gas diversion flue structures in some embodiments. Figure 2 This is a schematic diagram of the flue gas diversion flue structure provided in some embodiments of this application.

[0018] The correspondence between the reference numerals and the component names is as follows: 10. Flue gas diversion type flue structure, 100 First main flue, 110 Third flue condition detection device, 210 First diversion flue, 211 First flue condition detection device, 220 Afterburner chamber, 221 Temperature detection device, 230 First heat exchanger, 240 Second main flue, 241 First fan, 242 First purification device, 250 Third diversion flue, 260 Fourth diversion flue, 261 Second fan, 270 Gas storage device, 280 Pure oxygen supply device, 290 Desulfurization and denitrification device, 310 Second diversion flue, 311 Second flue condition detection device, 320 Second heat exchanger, 330 Third main flue, 331 Fourth fan, 332 Third fan, 333 Second purification device, 400 Ash removal silo. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0020] The chemical looping combustion system provided in this embodiment of the invention includes a chemical looping combustion device and a flue gas diversion structure 10. For example... Figure 1 and Figure 2As shown, the flue gas diversion type flue structure 10 includes: a first main flue 100; a first diversion flue 210, a combustion chamber 220, a first heat exchange device 230, a second main flue 240, a third diversion flue 250, a fourth diversion flue 260, a gas storage device 270, and a pure oxygen supply device 280. The inlet of the first diversion flue 210 is connected to the first main flue 100, and the outlets of the first diversion flue 210, the third diversion flue 250, the inlet of the first heat exchange device 230, and the outlet of the pure oxygen supply device 280 are all connected to the combustion chamber 220. The outlet of the first heat exchange device 230... The third diversion flue 250 and the fourth diversion flue 260 are connected to each other. The outlet of the third diversion flue 250 is connected to the inlet of the gas storage device 270. The pure oxygen supply device 280 is configured to supply oxygen to the combustion chamber 220 in a controlled manner. The gas storage device 270 is configured to store purified flue gas. The second diversion flue 310, the second heat exchange device 320, and the third main flue 330 are connected sequentially. The chemical looping combustion device includes a fuel reactor and an air reactor. The fuel reactor has a recirculated flue gas inlet and an exhaust outlet. The inlet of the first main flue 100 is connected to the exhaust outlet, and the outlet of the third main flue 330 is connected to the recirculated flue gas inlet. The flue gas discharged from the exhaust outlet contains a certain concentration of unreacted combustible gas.

[0021] The high-temperature flue gas discharged from the exhaust port of the chemical loop combustion device enters the first main flue 100 and is then diverted. A portion of the diverted flue gas flows through the first diversion flue 210 into the combustion chamber 220. Based on the content of combustible gas in the flue gas flowing from the first diversion flue 210 into the combustion chamber 220, the pure oxygen supply device 280 is controlled to supplement the combustion chamber 220 with a corresponding amount of oxygen, ensuring that the combustible gas and oxygen in the combustion chamber 220 react completely to produce water and carbon dioxide, thus forming... The flue gas is cooled by the first heat exchanger 230 and then flows to the second main flue 240. It is then diverted through the second main flue 240. A portion of the diverted flue gas flows through the third diversion flue 250 to the gas storage device 270. The flue gas entering the gas storage device 270 is purified flue gas (purification includes at least one of the following processes: dust removal, water vapor removal, and desulfurization), i.e., high-purity carbon dioxide. Another portion of the diverted flue gas from the second main flue 240 flows through the fourth diversion flue 250. Flue gas 260 flows back to the combustion chamber 220 to cool the combustion chamber 220 and prevent local overheating caused by the violent reaction of combustible gas and oxygen. Another portion of the flue gas flowing out of the first main flue gas 100 passes through the second diversion flue gas 310, the second heat exchange device 320 and the third main flue gas 330 in sequence, and then enters the fuel reactor from the recirculated flue gas inlet of the fuel reactor as fluidizing air. This fluidizes the fuel and oxygen carrier in the fuel reactor. The fuel undergoes pyrolysis in the fuel reactor to generate combustible gas and coke. During this process, the combustible gas in the fluidizing air and the combustible gas generated by fuel pyrolysis react with the oxidized oxygen carrier in the fuel reactor to consume the combustible gas and generate water, carbon dioxide and reduced oxygen carrier. That is, another portion of the flue gas flowing out of the first main flue gas 100 is reintroduced into the fuel reactor. The oxidized oxygen carrier in the fuel reactor removes the combustible gas in this other portion of the flue gas a second time, without the need for oxygen supplied by the pure oxygen supply device 280. This solution effectively reduces the amount of oxygen supplied by the pure oxygen supply device 280 while ensuring stable storage of high-purity carbon dioxide, resulting in lower operating costs for the flue gas diversion flue structure 10.

[0022] The air reactor has a reaction chamber, an air inlet, an oxygen carrier inlet, an air outlet, and an oxygen carrier outlet. Air enters the reaction chamber through the air inlet, causing the oxygen carrier within the chamber to fluidize. The air then exits the reaction chamber through the air outlet. The oxygen carrier includes both oxidized and reduced oxygen carriers. The reduced oxygen carrier (at a relatively high temperature) enters the air reactor from the fuel reactor through the oxygen carrier inlet. In the reaction chamber, the reduced oxygen carrier reacts with oxygen in the air to generate oxidized oxygen carrier and release a large amount of heat. The generated oxidized oxygen carrier then returns to the fuel reactor through the oxygen carrier outlet of the air reactor.

[0023] In some examples, such as Figure 1 and Figure 2 As shown, the pure oxygen supply device 280 is a pure oxygen generator. The pure oxygen generator is used to produce pure oxygen. This scheme requires less pure oxygen, so the energy consumption of the pure oxygen generator is lower.

[0024] In some examples, such as Figure 1 and Figure 2 As shown, the second main flue 240 has a first fan 241 and a first purification device 242, with the first fan 241 located downstream of the first purification device 242. The third main flue 330 has a second purification device 333, a third fan 332, and a fourth fan 331 arranged sequentially, with the third fan 332 and the fourth fan 331 located downstream of the second purification device 333. The first fan 241 is used to regulate the pressure from the first main flue 100 to the first branch flue 210, the third fan 332 is used to regulate the pressure from the first main flue 100 to the second branch flue 310, and the fourth fan 331 is used to regulate the pressure of the flue gas supplied to the fuel reactor. Both the first purification device 242 and the second purification device 333 include bag filters for removing dust from the flue gas. The dust outlet of the bag filter is connected to the dust removal silo 400. The dust filtered by the bag filter is fed into the dust removal silo 400 from the dust outlet and stored centrally in the dust removal silo 400.

[0025] In some examples, such as Figure 1 and Figure 2 As shown, the first heat exchange device 230 is the first heat exchange chamber. The flue gas diversion type flue structure 10 also includes a desulfurization and denitrification device 290, which is located in the first heat exchange chamber. The desulfurization and denitrification device 290 is used to remove sulfur dioxide (SO2) and nitrogen oxides (NOx) from the flue gas. X This achieves the purification of flue gas.

[0026] In some examples, the gas storage device 270 includes a compressor, a desulfurization bed, a drying bed, an adsorption bed, a refrigeration liquefaction unit, a distillation column, and a storage tank connected in sequence. High-purity CO2 gas entering the third diversion flue 250 is compressed through multiple stages to a pressure of 2-3 MPa by the compressor. It then passes through the desulfurization bed, drying bed, and adsorption bed to remove impurities such as grease and moisture. After passing through the refrigeration liquefaction unit to become liquid CO2, it enters the distillation column for further distillation and is finally transported to the storage tank for storage.

[0027] In some examples, such as Figure 1 and Figure 2As shown, the flue gas diversion type flue structure 10 also includes: a first flue gas state detection device 211, which is located in the first diversion flue 210 and is configured to detect the first state information of the flue gas; and a control device, which is electrically connected to both the first flue gas state detection device 211 and the pure oxygen supply device 280. The control device is configured to determine the data information of the oxygen supplied by the pure oxygen supply device 280 to the combustion chamber 220 according to the first state information, and control the pure oxygen supply device 280 to supply oxygen to the combustion chamber 220 according to the data information, so as to realize that the combustible gas in the combustion chamber 220 reacts with the oxygen exactly or almost completely to produce water and carbon dioxide.

[0028] In some embodiments, the first state information includes the flow rate of flue gas, the type of combustible gas in the flue gas, and the volume concentration of combustible gas in the flue gas. The fuel is coal or biomass, etc., and the type of combustible gas includes H2, CO, and CH4. The data information includes the flow rate. The control device is configured to determine the flow rate of oxygen supplied by the pure oxygen supply device 280 to the combustion chamber 220 according to the first state information using the formula (x / 2+y / 2+2z)×q L / min, and control the pure oxygen supply device 280 to supply oxygen to the combustion chamber 220 at the flow rate. x is the volume concentration of H2, y is the volume concentration of CO, z is the volume concentration of CH4, and q is the flue gas flow rate.

[0029] In some examples, such as Figure 1 and Figure 2 As shown, the fourth diversion flue 260 is equipped with a second fan 261. The flue gas diversion flue structure 10 also includes a temperature detection device 221, which is located in the combustion chamber 220. The temperature detection device 221 is configured to detect the actual temperature data of the combustion chamber 220. The control device is also electrically connected to the second fan 261 and the temperature detection device 221. The control device is configured to adjust the operating parameters of the second fan 261 according to the preset temperature data and the actual temperature data, so that the actual temperature data of the combustion chamber 220 is adjusted to meet the preset temperature data.

[0030] That is, if the preset temperature data is greater than the actual temperature data, the operating parameters of the second fan 261 are reduced, causing the speed of the second fan 261 to decrease. At this time, the amount of low-temperature flue gas flowing from the fourth diversion flue 260 to the combustion chamber 220 decreases, and the actual temperature of the combustion chamber 220 increases. If the preset temperature data is less than the actual temperature data, the operating parameters of the second fan 261 are increased, causing the speed of the second fan 261 to increase. At this time, the amount of low-temperature flue gas flowing from the fourth diversion flue 260 to the combustion chamber 220 increases, and the actual temperature of the combustion chamber 220 decreases.

[0031] In some embodiments, the operating parameters include at least one of voltage and current, and the preset temperature data ranges from 800°C to 900°C, so that the combustible gas and oxygen react in the optimal combustion range of 800°C to 900°C (the reaction releases heat).

[0032] In some examples, such as Figure 1 and Figure 2 As shown, the flue gas diversion type flue structure 10 further includes: a second flue gas status detection device 311, which is located in the second diversion flue 310 and is configured to detect the second status information of the flue gas; and a third flue gas status detection device 110, which is located in the first main flue 100 and is configured to detect the third status information of the flue gas. The flue gas diversion type flue structure 10 also includes: a display device. The control device is electrically connected to the display device, the second flue gas status detection device 311, and the third flue gas status detection device 110. The display device displays the first status information, the second status information, and the third status information for the operator to observe and verify. Theoretically, the first status information + the second status information = the third status information.

[0033] In some examples, such as Figure 1 and Figure 2 As shown, the second heat exchange device 320 is the second heat exchange chamber. Both the first and second heat exchange chambers are equipped with a high-temperature economizer, a low-temperature economizer, and an air preheater. The high-temperature economizer, the low-temperature economizer, and the air preheater are used to recover and utilize the heat from the flue gas.

[0034] 1. When the chemical loop combustion equipment is in a hot start-up, combustion state switching, or poor reaction performance state: the power of the first fan 241 is adjusted to the first set power (at this time, the load of the first fan 241 is 0-50%), and the power of the third fan 332 is adjusted to the second set power (at this time, the load of the third fan 332 is 60%-100%). The second set power is greater than the first set power, so that most of the flue gas in the first main flue 100 is supplied to the fuel reactor from the second diversion flue 310. At the same time, the heat exchange capacity of the second heat exchange device 320 is adjusted to the first set heat exchange capacity (at this time, the heat exchange load of the second heat exchange device 320 is 0-50%), so that the second heat exchange device 320 is in a low load operation state. At this time, the flue gas returns to the fuel reactor at a higher temperature, maintaining the fuel reactor in a self-heating operation state.

[0035] Hot start-up: The initial state of both the fuel reactor and the air reactor is at room temperature. There is no material circulation between the fuel reactor and the air reactor. During the hot start-up process, the fuel reactor is heated by biomass combustion, natural gas combustion, or coal combustion, gradually increasing the temperature from room temperature to above 950°C. At the same time, a stable material circulation is established between the fuel reactor and the air reactor. At this time, the fluidizing air in both the fuel reactor and the air reactor is air. Therefore, the combustion mode at this time is conventional air combustion, that is, oxygen in the air reacts with fuel to release heat. Combustion State Switching: Chemical looping combustion differs fundamentally from conventional air combustion. Air combustion involves direct contact between oxygen in the air and fuel, releasing heat. Chemical looping combustion, on the other hand, involves oxygen in the air oxidizing the oxygen carrier, transferring oxygen atoms from the oxygen carrier into its lattice, becoming lattice oxygen. The oxygen carrier then reacts with the fuel, and the lattice oxygen combines with carbon and hydrogen elements in the fuel to produce CO2 and H2O. Switching the combustion state involves switching from air combustion to chemical looping combustion. A simplified process is as follows: All fuel is added to the fuel reactor, while no fuel is added to the air reactor. The fluidizing air in the air reactor is air, while the fluidizing air in the fuel reactor is carbon dioxide and water vapor. At this point, the fuel in the fuel reactor undergoes pyrolysis and gasification, producing combustible gases such as CH4, CO, and H2. These combustible gases react with the oxygen carrier in the fuel reactor, removing lattice oxygen from it. The oxygen carrier, now devoid of lattice oxygen, enters the air reactor, where oxygen from the air oxidizes it, replenishing the lattice oxygen. The oxidized oxygen carrier then returns to the fuel reactor. Poor reaction performance can be mainly divided into two aspects: first, low carbon capture efficiency, incomplete fuel conversion in the fuel reactor, and unconverted coke flowing into the air reactor for combustion, resulting in reduced carbon capture efficiency; second, incomplete conversion of combustible gases in the fuel reactor, with a large amount of unburned combustible gases in the flue gas at the fuel reactor outlet.

[0036] II. When the chemical loop combustion equipment is in stable operation: Increase the power of the first fan 241 to the third set power and decrease the power of the third fan 332 to the fourth set power. The third set power is greater than the fourth set power, so that most of the flue gas in the first main flue duct 100 is diverted to the first diversion flue duct 210. The control device determines the flow rate of oxygen supplied by the pure oxygen supply device 280 to the combustion chamber 220 according to the formula (x / 2+y / 2+2z)×q L / min, and controls the pure oxygen supply device 280 to supply oxygen to the combustion chamber 220 at this flow rate, keeping the combustion chamber 220 in the optimal combustion range of 800℃~900℃. This can better ensure the purity of CO2 stored in the gas storage device 270. In addition, the heat exchange capacity of the second heat exchange chamber and the power of the fourth fan 331 are adjusted to maintain the stability of the actual temperature and actual flow rate of the fluidizing air returning to the fuel reactor. That is: if the actual temperature of the fluidizing air returning to the fuel reactor is less than the set temperature, the heat exchange capacity of the second heat exchange chamber is reduced; if the actual temperature of the fluidizing air returning to the fuel reactor is greater than the set temperature, the heat exchange capacity of the second heat exchange chamber is increased; if the actual flow rate of the fluidizing air returning to the fuel reactor is less than the set flow rate, the power of the fourth blower 331 is increased; if the actual flow rate of the fluidizing air returning to the fuel reactor is greater than the set flow rate, the heat exchange capacity of the second heat exchange chamber is reduced (the fuel reactor is equipped with a second temperature detection device and a flow detection device. The second temperature detection device detects the actual temperature of the fluidizing air returning to the fuel reactor, and the flow detection device detects the actual flow rate of the fluidizing air returning to the fuel reactor).

[0037] 3. When the chemical loop combustion equipment is switched to the shutdown state: gradually reduce the power of the first blower 241, increase the heat exchange capacity of the second heat exchange chamber to the second set heat exchange capacity (the second set heat exchange capacity is greater than the first set heat exchange capacity), so that the temperature of the flue gas entering the fuel reactor from the third main flue 330 gradually decreases, the fuel reactor gradually cools down, and finally the furnace is shut down.

[0038] In summary, the technical solution provided by this invention involves the following: High-temperature flue gas discharged from the exhaust port of the chemical loop combustion device is diverted after entering the first main flue. A portion of the diverted flue gas flows through the first diversion flue to the combustion chamber. Based on the combustible gas content in the flue gas flowing from the first diversion flue to the combustion chamber, the pure oxygen supply device is controlled to supplement the combustion chamber with a corresponding amount of oxygen, ensuring that the combustible gas and oxygen in the combustion chamber react completely to produce water and carbon dioxide. The resulting flue gas is then cooled by the first heat exchange device and flows to the second main flue. It is then diverted again through the second main flue. A portion of the diverted flue gas flows through the third diversion flue to the gas storage device. The flue gas entering the gas storage device is purified flue gas, i.e., high-purity carbon dioxide. Another portion of the diverted flue gas flows back to the combustion chamber through the fourth diversion flue for further purification of the combustion chamber. Cooling is achieved to prevent the combustible gas from reacting violently with oxygen and releasing heat, which could lead to localized overheating. Another portion of the flue gas diverted from the first main flue passes through the second diversion flue, the second heat exchanger, and the third main flue before entering the fuel reactor through the recirculated flue gas inlet. This serves as fluidizing air, causing the fuel and oxygen carrier within the reactor to fluidize. The fuel undergoes pyrolysis within the reactor, producing combustible gases and coke. During this process, the combustible gases in the fluidizing air and those generated from fuel pyrolysis react with the oxidized oxygen carrier in the reactor, consuming the combustible gases and generating water, carbon dioxide, and reduced oxygen carrier. This second portion of the flue gas diverted from the first main flue is then reintroduced into the fuel reactor, where the oxidized oxygen carrier further removes the combustible gases, eliminating the need for a pure oxygen supply system. This design effectively reduces the amount of oxygen supplied by a pure oxygen supply system while ensuring stable storage of high-purity carbon dioxide, resulting in lower operating costs for the diversion flue structure.

[0039] In the description of this invention, it should be noted that the terms "upper", "lower", "one side", "the other side", "one end", "the other end", "side", "opposite", "four corners", "periphery", "'mouth' structure", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the "invention" and simplifying the description, and do not indicate or imply that the structure referred to has a specific orientation, or is constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0040] In the description of the embodiments of the present invention, unless otherwise expressly specified and limited, the terms "connection," "direct connection," "indirect connection," "fixed connection," "installation," and "assembly" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. The terms "installation," "connection," and "fixed connection" can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0041] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be defined by the appended claims.

Claims

1. A flue gas diversion type flue structure, applied to a chemical looping combustion system, characterized in that, include: First main flue; The system comprises a first diversion flue, a combustion chamber, a first heat exchanger, a second main flue, a third diversion flue, a fourth diversion flue, a gas storage device, and a pure oxygen supply device. The inlet of the first diversion flue is connected to the first main flue. The outlets of the first diversion flue, the fourth diversion flue, the inlet of the first heat exchanger, and the pure oxygen supply device are all connected to the combustion chamber. The outlet of the first heat exchanger is connected to the inlets of the third and fourth diversion flues. The outlet of the third diversion flue is connected to the inlet of the gas storage device. The pure oxygen supply device is configured to supply oxygen to the combustion chamber in a controlled manner. The gas storage device is configured to store purified flue gas. The system comprises a second diversion flue, a second heat exchange device, and a third main flue. The inlet of the second diversion flue is connected to the first main flue, and the outlet of the second diversion flue, the second heat exchange device, and the inlet of the third main flue are connected in sequence.

2. The flue gas diversion type flue structure according to claim 1, characterized in that, Also includes: A first flue gas condition detection device is installed in the first diversion flue gas, and the first flue gas condition detection device is configured to detect the first state information of the flue gas. and The control device is electrically connected to the first flue gas state detection device and the pure oxygen supply device. The control device is configured to determine the data information of the oxygen supplied by the pure oxygen supply device to the combustion chamber based on the first state information, and control the pure oxygen supply device to supply oxygen to the combustion chamber according to the data information.

3. The flue gas diversion type flue structure according to claim 2, characterized in that, The first state information includes the flue gas flow rate, the type of combustible gas in the flue gas, and the volume concentration of combustible gas in the flue gas. The type of combustible gas includes H2, CO, and CH4. The data information includes the flow rate. The control device is configured to determine the flow rate of oxygen supplied by the pure oxygen supply device to the combustion chamber based on the first state information using the formula (x / 2+y / 2+2z)×q L / min, and to control the pure oxygen supply device to supply oxygen to the combustion chamber at the flow rate. Here, x is the volume concentration of H2, y is the volume concentration of CO, z is the volume concentration of CH4, and q is the flue gas flow rate.

4. The flue gas diversion type flue structure according to claim 1, characterized in that, The fourth diversion flue is equipped with a second fan, and the flue gas diversion flue structure further includes: A temperature detection device is installed in the afterburner chamber, and the temperature detection device is configured to detect the actual temperature data of the afterburner chamber; and The control device is electrically connected to the second fan and the temperature detection device. The control device is configured to adjust the operating parameters of the second fan according to the preset temperature data and the actual temperature data, so that the actual temperature data of the combustion chamber is adjusted to meet the preset temperature data.

5. The flue gas diversion type flue structure according to claim 4, characterized in that, The operating parameters include at least one of voltage and current, and the preset temperature data ranges from 800℃ to 900℃.

6. The flue gas diversion type flue structure according to claim 1, characterized in that, The second main flue has a first fan and a first purification device, with the first fan located downstream of the first purification device. The third main flue has a second purification device, a third fan, and a fourth fan arranged in sequence, with the third fan and the fourth fan located downstream of the second purification device.

7. The flue gas diversion type flue structure according to claim 6, characterized in that, Both the first purification device and the second purification device include a bag filter dust collector.

8. The flue gas diversion flue structure according to any one of claims 1 to 7, characterized in that, Also includes: The second flue gas status detection device is located in the second diversion flue and is configured to detect the second status information of the flue gas. and The third flue gas status detection device is located in the first main flue gas and is configured to detect the third status information of the flue gas.

9. The flue gas diversion flue structure according to any one of claims 1 to 7, characterized in that, The first heat exchange device is a first heat exchange chamber, and the second heat exchange device is a second heat exchange chamber. Both the first and second heat exchange chambers are equipped with a high-temperature economizer, a low-temperature economizer, and an air preheater. The gas storage device includes a compressor, a desulfurization bed, a drying bed, an adsorption bed, a refrigerated liquefaction unit, a distillation column, and a storage tank connected in sequence. The flue gas diversion flue structure also includes: The desulfurization and denitrification device is located in the first heat exchange chamber.

10. A chemical looping combustion system, characterized in that, The invention includes a chemical looping combustion device and a flue gas diversion structure as described in any one of claims 1 to 9. The chemical looping combustion device includes a fuel reactor having a recirculated flue gas inlet and a flue gas outlet. The inlet of the first main flue gas duct is connected to the flue gas outlet, and the outlet of the third main flue gas duct is connected to the recirculated flue gas inlet.

Images