Chemical looping air reactor structure and control method for wide load operation
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
- Filing Date
- 2026-03-12
- Publication Date
- 2026-06-09
AI Technical Summary
Existing chemical looping combustion technology suffers from problems such as narrow adjustment range or complex systems and poor economy when operating under variable loads, making it difficult to achieve wide-load operation.
Design a chemical loop air reactor structure, including an air reactor, a gas-solid separator, and a return feeder. Utilize the particle size difference between the oxygen carrier and the circulating ash, and adjust the circulation volume of the circulating ash through the ash inlet and outlet to achieve wide-load operation.
Stable operation was achieved within the load range of 30-100%, with the oxygen carrier temperature remaining stable at ≥950℃, ensuring a reaction temperature of ≥900℃ for the fuel reactor. The system is simple, has low investment costs, and reliable control logic.
Smart Images
Figure CN122170404A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of chemical looping combustion technology, specifically to a chemical looping air reactor structure and control method for wide-load operation. Background Technology
[0002] Chemical looping combustion is a novel combustion technology that achieves efficient and clean fuel combustion and in-situ CO2 capture by circulating oxygen between an air reactor and a fuel reactor using an oxygen carrier. This technology can be applied not only to power generation but also to the chemical industry for the production of syngas or hydrogen. With the increasing proportion of renewable energy connected to the grid, the demand for grid peak shaving is becoming increasingly prominent. Power generation and chemical plants urgently need flexible load-changing operation capabilities; therefore, load-changing operation capability has become one of the essential key capabilities for the large-scale application of chemical looping combustion technology.
[0003] Based on the technical characteristics of chemical looping combustion, fuel reactors typically require temperatures above 900°C to ensure normal reaction operation. Since the reaction within the fuel reactor is strongly endothermic, the required heat primarily comes from the sensible heat carried by the high-temperature oxygen carrier flowing from the air reactor. This necessitates maintaining an even higher operating temperature in the air reactor, typically above 950°C. The oxidation reaction within the air reactor is exothermic; therefore, during rated load design, a certain amount of heating surface area must be provided to absorb excess heat, thereby maintaining the air reactor temperature at the target level. However, when the unit operates at reduced load, the heat input of the air reactor decreases accordingly. Since the heat exchange area of the heating surface is designed for rated load, the decrease in heat absorption is relatively small, leading to a drop in the air reactor temperature, which in turn causes a decrease in the temperature of the oxygen carrier flowing to the fuel reactor. When the oxygen carrier temperature is insufficient, the fuel reactor may be unable to maintain an operating temperature ≥900°C, resulting in deterioration or even interruption of the reaction.
[0004] To address the aforementioned variable load operation problem, existing technologies have proposed two main solutions. Patent application CN121025452A discloses a variable load system and control method for chemical looping combustion based on flue gas recirculation. This system supplements heat to the fuel reactor by adjusting the flow rate and temperature of the recirculated flue gas to maintain the reaction temperature of the fuel reactor, thereby achieving variable load operation. Patent application CN120907140A discloses a variable load chemical looping combustion system and its usage method. This system achieves variable load operation by installing 1-N load regulators in parallel between the air reactor and the fuel reactor to adjust the oxygen carrier circulation flow rate, thereby maintaining the reaction temperature of the fuel reactor.
[0005] However, the aforementioned existing technologies still have significant drawbacks: First, in flue gas recirculation schemes, the heat input of the recirculated flue gas accounts for a relatively small proportion of the heat load of the chemical looping device itself, resulting in limited heat regulation capabilities and difficulty in achieving wide-range load regulation. Second, while load regulator schemes can broaden the load regulation range, the parallel regulator setup significantly increases system complexity and equipment investment costs, and multi-loop coordinated control is challenging, hindering engineering applications. Therefore, existing chemical looping combustion variable load technologies generally suffer from narrow regulation ranges or complex systems and poor economic efficiency, necessitating the development of a wide-load operation technology scheme with a wide regulation range, simple system, and convenient control. Summary of the Invention
[0006] The purpose of this application is to provide a structure and control method for a chemical looping air reactor that operates under wide load conditions, thereby solving the problems of system complexity and high equipment investment costs in existing chemical looping combustion systems when operating under wide load conditions.
[0007] The technical solution adopted by this application to solve its technical problem is: In a first aspect, a chemical loop air reactor structure for wide-load operation is provided, comprising an air reactor, a gas-solid separator, and a return feeder. The air reactor has a fluidizing air chamber, an insulated furnace, and a water-cooled film furnace connected sequentially from bottom to top, and an air distribution plate is provided between the fluidizing air chamber and the insulated furnace. The insulated furnace is provided with an oxygen carrier inlet and an oxygen carrier outlet arranged below the oxygen carrier inlet, and the oxygen carrier outlet is provided with a temperature sensor for measuring the temperature of the oxygen carrier. The top of the water-cooled film furnace is connected to the inlet of the gas-solid separator, the solid phase outlet of the gas-solid separator is connected to the inlet of the return feeder, and the outlet of the return feeder is connected to the insulated furnace. The return feeder is provided with an ash inlet for adding circulating ash into its inner cavity and an ash outlet for discharging circulating ash. The insulated furnace is filled with oxygen carrier and circulating ash. The oxygen carrier is in a bubbling fluidized state in the insulated furnace. The circulating ash circulates between the air reactor, the gas-solid separator, and the return feeder. The circulation volume is changed by the ash inlet and the ash outlet to adjust the heat absorption of the water-cooled film furnace and achieve wide-load operation.
[0008] Furthermore, the particle size of the oxygen carrier is larger than that of the circulating ash, and the particle size distribution range of the oxygen carrier is smaller than that of the circulating ash.
[0009] Furthermore, the particle size characteristic D50 of the oxygen carrier is 200-500 μm, and the particle size characteristic D50 of the recycled ash is 20-100 μm.
[0010] Furthermore, the bottom and top of the water-cooled film fireplace are respectively provided with pressure taps, and the two pressure taps are connected to a differential pressure measuring device for detecting the gas-solid flow pressure drop inside the water-cooled film fireplace.
[0011] Furthermore, the flow velocity of the flue gas inside the insulated furnace is 1.5 to 5 m / s.
[0012] Furthermore, the gas-solid separator includes a cyclone separator.
[0013] Furthermore, the temperature of the reduced oxygen carrier entering from the oxygen carrier inlet is ≥900℃, and the temperature of the oxidized oxygen carrier flowing out from the oxygen carrier outlet is ≥950℃.
[0014] Secondly, a control method for a chemical loop air reactor structure operating under wide loads is provided, comprising: a reduced oxygen carrier entering an adiabatic furnace from an oxygen carrier inlet; circulating ash entering the adiabatic furnace from a return feeder; and fluidizing air entering the adiabatic furnace from a fluidizing air chamber via an air distribution plate; the oxygen carrier in the adiabatic furnace undergoes an oxidation reaction with the air, releasing heat to heat the oxygen carrier and circulating ash to a target temperature; the oxidized oxygen carrier flows out from the oxygen carrier outlet and enters a fuel reactor; the circulating ash is carried by flue gas into a water-cooled membrane furnace for heat exchange, and then returns to the adiabatic furnace via a gas-solid separator and a return feeder; the circulating ash volume is adjusted by adding and discharging ash through an ash inlet based on the temperature of the oxidized oxygen carrier detected by a temperature sensor.
[0015] Furthermore, it also includes: When the load is reduced, if the temperature sensor detects that the temperature of the oxidized oxygen carrier is lower than the first temperature threshold, part of the circulating ash is discharged from the return feeder through the ash discharge port until the temperature sensor detects that the temperature of the oxidized oxygen carrier is within the target temperature range. When the load is increased, if the temperature sensor detects that the temperature of the oxidized oxygen carrier is higher than the second temperature threshold, circulating ash is added to the return feeder through the ash inlet until the temperature sensor detects that the temperature of the oxidized oxygen carrier is within the target temperature range. Wherein, the first temperature threshold < the target temperature < the second temperature threshold.
[0016] Furthermore, the temperature of the reduced oxygen carrier is ≥900℃, with a target temperature of 950~1100℃.
[0017] The beneficial effects of this application are: The chemical loop air reactor structure and control method for wide-load operation provided in this application embodiment utilizes the circulating flow of ash between the air reactor, gas-solid separator, and return feeder. By changing the circulation volume of the ash through the ash inlet and outlet, the heat absorption ratio of the water-cooled film furnace can be adjusted within the load range of 30-100%, ensuring that the temperature of the oxygen carrier flowing from the air reactor to the fuel reactor is stabilized at ≥950℃. This, in turn, ensures that the fuel reactor maintains a reaction temperature of ≥900℃, achieving stable operation of the system under wide loads.
[0018] Compared with existing technologies, this application only requires the addition of ash inlet and ash outlet on the return feeder, without the need for complex equipment such as multiple parallel load regulators. The system modification is simple and the equipment investment cost is low. The temperature of the oxygen carrier is detected by a temperature sensor and the circulating ash amount is adjusted accordingly. The control logic is simple and reliable, which is conducive to engineering application and promotion. Attached Figure Description
[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is a schematic diagram of the structure of the chemical looping air reactor provided in the embodiments of this application.
[0021] Figure label: 1-Air reactor; 2-Gas-solid separator; 3-Return feeder; 4-Fluidized air chamber; 5-Insulated furnace; 6-Water-cooled membrane furnace; 7-Air distribution plate; 8-Oxygen carrier inlet; 9-Oxygen carrier outlet; 10-Temperature sensor; 11-Oxygen carrier; 12-Circulating ash; 13-Ash inlet; 14-Ash outlet; 15-Pressure tap; 16-Differential pressure measuring device. Detailed Implementation
[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.
[0023] In the description of this application, the terms "upper," "lower," "left," "right," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Unless otherwise specified, the above-mentioned orientational descriptions can be flexibly set in actual application, provided that the relative positional relationships shown in the accompanying drawings are satisfied.
[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and 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 this application according to the specific circumstances.
[0025] See Figure 1 This application provides a wide-load operation chemical loop air reactor structure, including an air reactor 1, a gas-solid separator 2, and a return feeder 3. The air reactor 1 has a fluidizing air chamber 4, an insulated furnace 5, and a water-cooled film furnace 6 connected sequentially from bottom to top, with an air distribution plate 7 between the fluidizing air chamber 4 and the insulated furnace 5. The insulated furnace 5 has an oxygen carrier inlet 8 and an oxygen carrier outlet 9 arranged below the oxygen carrier inlet 8. The oxygen carrier outlet 9 is equipped with a temperature sensor 10 for measuring the temperature of the oxygen carrier 11. The top of the water-cooled film furnace 6 is connected to the inlet of the gas-solid separator 2. The solid phase outlet of the gas-solid separator 2 is connected to the inlet of the return feeder 3, and the outlet of the return feeder 3 is connected to the insulated furnace 5. The return feeder 3 is provided with an ash inlet 13 for adding circulating ash 12 into its inner cavity and an ash outlet 14 for discharging circulating ash 12. The insulated furnace 5 is filled with oxygen carrier 11 and circulating ash 12. The oxygen carrier 11 is in a bubbling fluidized state in the insulated furnace 5. The circulating ash 12 circulates between the air reactor 1, the gas-solid separator 2 and the return feeder 3, and the circulation volume is changed by the ash inlet 13 and the ash outlet 14 to adjust the heat absorption of the water-cooled film furnace 6 and achieve wide-load operation.
[0026] Specifically, the air reactor 1 has a fluidizing air chamber 4, an insulated furnace 5, and a water-cooled film furnace 6 connected sequentially from bottom to top. The fluidizing air chamber 4 is located at the bottom of the air reactor 1 and is used to receive fluidizing air and provide a uniform airflow distribution for the insulated furnace 5. The insulated furnace 5 is located above the fluidizing air chamber 4 and is used to provide an oxidation reaction space for the oxidation reaction of the oxygen carrier 11, and to use the heat released by the oxidation reaction to heat the oxygen carrier 11 and the circulating ash 12 to the target temperature. The water-cooled film furnace 6 is located above the insulated furnace 5, and its heat exchange area is designed according to the rated load to absorb the heat of the circulating ash carried by the flue gas and maintain the thermal balance of the system. An air distribution plate 7 is provided between the fluidizing air chamber 4 and the insulated furnace 5. The air distribution plate 7 is used to evenly distribute the fluidizing air in the fluidizing air chamber 4 and send it into the insulated furnace 5, while supporting the oxygen carrier 11 and the circulating ash 12 in the insulated furnace 5 and preventing the oxygen carrier 11 and the circulating ash 12 from falling into the fluidizing air chamber 4. The oxygen carrier inlet 8 is located in the middle region of the adiabatic furnace 5 to receive the reduced oxygen carrier 11 returned from the fuel reactor (not shown in the figure). The oxygen carrier outlet 9 is located below the oxygen carrier inlet 8, specifically in the lower region of the adiabatic furnace 5, to discharge the oxidized high-temperature oxygen carrier 11 and send it to the fuel reactor. A temperature sensor 10 is installed at the oxygen carrier outlet 9 to measure the temperature of the oxidized oxygen carrier 11 flowing out of the outlet 9 in real time, providing key parameters for load regulation and control.
[0027] The top of the water-cooled film furnace 6 is connected to the inlet of the gas-solid separator 2, which separates the circulating ash 12 from the flue gas flow. The solid phase outlet at the bottom of the gas-solid separator 2 is connected to the inlet of the return feeder 3, and the separated circulating ash 12 enters the return feeder 3. The outlet of the return feeder 3 is connected to the insulated furnace 5, which is used to return the circulating ash 12 to the insulated furnace 5. The return feeder 3 is equipped with an ash inlet 13 and an ash outlet 14. The ash inlet 13 is used to add circulating ash 12 into the inner cavity of the return feeder 3, and the ash outlet 14 is used to discharge some of the circulating ash 12 from the inner cavity of the return feeder 3. Through the coordinated operation of the ash inlet 13 and the ash outlet 14, the circulation volume of circulating ash 12 in the system can be adjusted.
[0028] The chemical loop air reactor structure provided in this application embodiment has a wide-load operation. The oxygen carrier 11 and the circulating ash 12 coexist in the adiabatic furnace 5 but have different flow characteristics. The oxygen carrier 11 mainly participates in the oxidation reaction and flows downward to be discharged, while the circulating ash 12 mainly participates in heat regulation and flows upward to circulate. The two functions are separated and the flow direction is clear, avoiding the separation and recovery problems caused by material mixing. During operation, the oxygen carrier 11 is in a bubbling fluidized state in the adiabatic furnace 5 and undergoes an oxidation reaction in full contact with the fluidized air. The heat released by the oxidation reaction heats the oxygen carrier 11 and the circulating ash 12 to the target temperature. The circulating ash 12 circulates between the air reactor 1, the gas-solid separator 2, and the return feeder 3 to form an independent circulation loop. By changing the circulation volume of the circulating ash 12 through the ash inlet 13 and the ash outlet 14, the gas-solid concentration and heat absorption in the water-cooled film furnace 6 can be adjusted. This allows for adjustment of the heat absorption ratio of the water-cooled film furnace within the 30-100% load range, ensuring that the heat absorption matches the load. This stabilizes the temperature of the oxygen carrier flowing from the air reactor to the fuel reactor at ≥950℃, thereby ensuring that the fuel reactor maintains a reaction temperature of ≥900℃ and achieving stable operation of the system under wide loads.
[0029] When the system operates at reduced load, the circulation volume of circulating ash 12 is reduced, lowering the gas-solid concentration and heat absorption in the water-cooled film furnace 6, thus reducing heat loss and maintaining the high-temperature environment in the insulated furnace 5. When the system operates at increased load, the circulation volume of circulating ash 12 is increased, enhancing the heat absorption capacity of the water-cooled film furnace 6 and preventing the temperature of the insulated furnace 5 from becoming too high. This adjustment method is responsive and has a wide adjustment range. Compared with existing technologies, this application only requires adding an ash inlet 13 and an ash outlet 14 to the return feeder 3, without the need for complex equipment such as multiple parallel load regulators. The system modification is simple and the equipment investment cost is low. The temperature sensor 10 detects the temperature of the oxygen carrier 11 and provides feedback to adjust the circulating ash volume. The control logic is simple and reliable, which is conducive to engineering applications and promotion.
[0030] Oxygen carrier 11, as the oxygen-carrying medium for chemical looping combustion, needs to possess good fluidization performance and reactivity; its particle size selection must balance fluidization quality and reaction rate. Circulating ash 12, as the heat conditioning medium, primarily absorbs and transfers heat; its particle size selection must ensure it can be effectively carried by the flue gas into the water-cooled film fireplace 6. In some embodiments, see... Figure 1 The particle size of oxygen carrier 11 is larger than that of circulating ash 12, and the particle size distribution range of oxygen carrier 11 is smaller than that of circulating ash 12.
[0031] Correspondingly, by setting the particle size of the oxygen carrier 11 to be larger than that of the circulating ash 12, the difference in particle size can be used to achieve functional separation and directional flow between the oxygen carrier 11 and the circulating ash 12. Under the bubbling fluidized state of the adiabatic furnace 5, the larger-diameter oxygen carrier 11 has a higher terminal settling velocity and is less likely to be carried into the water-cooled film furnace 6 by the rising airflow, thus mainly remaining in the adiabatic furnace 5 to participate in the oxidation reaction; the smaller-diameter circulating ash 12 has a lower terminal settling velocity and is easily carried into the water-cooled film furnace 6 by the flue gas, thereby achieving the functions of heat absorption and circulation regulation. Meanwhile, the oxygen carrier 11 adopts a narrow sieve particle size distribution, while the circulating ash 12 adopts a wide sieve particle size distribution. By utilizing the smaller particle size distribution range of the oxygen carrier 11 than that of the circulating ash 12, the particle size of the oxygen carrier 11 is ensured to be relatively uniform, reducing the loss of oxygen carrier 11 caused by fine particles being carried into the circulating ash loop by the airflow, and lowering the replenishment cost of the oxygen carrier 11. On the other hand, the wider particle size distribution range of the circulating ash 12 is conducive to improving its adaptability and heat exchange efficiency under different load conditions, thereby improving the load regulation response speed and thermal efficiency of the system.
[0032] In some embodiments, the particle size characteristic D50 of the oxygen carrier 11 is 200–500 μm, and the particle size characteristic D50 of the circulating ash 12 is 20–100 μm. D50 represents the particle size value corresponding to a cumulative particle size distribution of 50%, indicating that particles with a size greater than and less than this value each account for 50%, also known as median particle size or median particle size.
[0033] Correspondingly, when the D50 of the oxygen carrier 11 is 200–500 μm, under the typical operating gas velocity (1.5–5 m / s) of the adiabatic furnace 5, the oxygen carrier 11 can maintain a good bubbling fluidization state, fully contact and react with the air, and at the same time, its terminal settling velocity is greater than the operating gas velocity, making it less likely to be carried by the airflow into the upper water-cooled film furnace 6. When the D50 of the circulating ash 12 is 20–100 μm, its terminal settling velocity is less than the operating gas velocity of the adiabatic furnace 5, and it can be effectively carried by the flue gas into the water-cooled film furnace 6, forming a rapid fluidization or pneumatic conveying state within the water-cooled film furnace 6, and fully contacting the wall of the water-cooled film furnace 6 for heat exchange, achieving efficient heat absorption.
[0034] In some embodiments, see Figure 1 The bottom and top of the water-cooled film fireplace chamber 6 are respectively provided with pressure taps 15. The two pressure taps 15 are connected to the differential pressure measuring device 16 to detect the gas-solid flow pressure drop inside the water-cooled film fireplace chamber 6.
[0035] Specifically, pressure tap 15 is a pressure measurement interface installed on the furnace wall, equipped with an anti-clogging device to prevent solid particles from clogging it. The bottom pressure tap 15 can be located in the transition area between the water-cooled film furnace 6 and the insulated furnace 5, while the top pressure tap 15 is located in the connection area between the water-cooled film furnace 6 and the inlet of the gas-solid separator 2. The differential pressure measuring device 16 can be a differential pressure transmitter or a U-tube differential pressure gauge, used to measure the pressure difference between the two pressure taps 15 in real time. Since the gas-solid flow pressure drop in the water-cooled film furnace 6 is closely related to the solid particle concentration, monitoring the pressure drop change can indirectly reflect the concentration and circulation volume of circulating ash 12 in the furnace, providing auxiliary judgment basis for load regulation and control.
[0036] Correspondingly, by setting up a differential pressure measuring device 16, the pressure difference inside the water-cooled film fireplace 6 can be measured, thereby reflecting the gas-solid flow state and the concentration of circulating ash 12 inside the water-cooled film fireplace 6. Operators or automatic control systems can predict temperature change trends based on pressure drop trends, achieving feedforward control and improving the response speed and control accuracy of load regulation. Pressure drop monitoring can serve as a redundant monitoring method for the temperature sensor 10. When the temperature sensor 10 malfunctions or has measurement deviations, the pressure drop signal can serve as a backup judgment basis, enhancing the reliability and safety of the system. Through the correspondence between pressure drop and the circulation volume of circulating ash 12, the operating parameters of the ash inlet 13 and the ash outlet 14 can be calibrated and optimized, achieving precise control of the circulation volume of circulating ash 12 and improving the fineness of load regulation.
[0037] In some embodiments, the flow velocity of the flue gas in the adiabatic furnace 5 is 1.5–5 m / s. Correspondingly, within this velocity range, the oxygen carrier 11 in the adiabatic furnace 5 is in a bubbling fluidized state, resulting in good gas-solid contact, a fast oxidation reaction rate, and high regeneration of the oxygen carrier 11. This velocity range matches the particle size of the oxygen carrier 11 and the circulating ash 12, ensuring that the oxygen carrier 11 is not significantly entrained by the airflow, reducing its loss. The circulating ash 12 can be effectively carried by the flue gas into the water-cooled film furnace 6 to achieve heat regulation, while avoiding the problem of excessively high flow velocities leading to excessively low circulating ash 12 concentration and reduced heat exchange efficiency.
[0038] In some embodiments, see Figure 1 The gas-solid separator 2 includes a cyclone separator. Specifically, the inlet of the cyclone separator is tangentially connected to the top outlet of the water-cooled film fireplace 6. The flue gas carrying the circulating ash 12 enters the cyclone separator tangentially. Under the action of centrifugal force, the solid particles are thrown against the wall of the separator and move downwards, and are discharged from the solid phase outlet at the bottom into the return feeder 3. The purified flue gas is discharged from the exhaust pipe at the top center and enters the subsequent heat recovery or emission system.
[0039] Correspondingly, the cyclone separator exhibits high separation efficiency for particles in the 20–100 μm diameter range, effectively recovering circulating ash and maintaining the system's circulating ash volume to ensure the realization of heat regulation functions. With no moving parts, the cyclone separator boasts excellent high-temperature resistance, enabling long-term stable operation in environments exceeding 950°C. It requires minimal maintenance, offers high reliability, and is suitable for the high-temperature conditions of chemical loop combustion systems. Furthermore, the cyclone separator features moderate pressure drop, reasonable system energy consumption, and a simple structure with low manufacturing costs, thus reducing equipment investment costs.
[0040] In some embodiments, see Figure 1 The temperature of the reduced oxygen carrier 11 entering from the oxygen carrier inlet 8 is ≥900℃, and the temperature of the oxidized oxygen carrier 11 flowing out from the oxygen carrier outlet 9 is ≥950℃.
[0041] Correspondingly, the reduced oxygen carrier 11 returns from the fuel reactor and enters the adiabatic furnace 5 through the oxygen carrier inlet 8. It carries the reaction heat from the fuel reactor and maintains a temperature above 900°C. This temperature ensures that the oxygen carrier 11 can rapidly undergo an oxidation reaction with the air after entering the adiabatic furnace 5, which is beneficial for improving the thermal efficiency of the air reactor 1. The oxidized oxygen carrier 11 flows out from the oxygen carrier outlet 9 at a temperature ≥950°C, preferably 950–1100°C. This temperature ensures that the oxygen carrier 11 carries sufficient sensible heat into the fuel reactor to meet the heat requirements of the strongly endothermic reaction within the fuel reactor, maintains the operating temperature of the fuel reactor at ≥900°C, and ensures the normal progress of the fuel reaction and the in-situ CO2 capture effect.
[0042] This application also provides a method for controlling a chemical looping air reactor structure operating under wide load conditions, comprising the following steps: S1, Feeding and Fluidization.
[0043] Specifically, reduced oxygen carrier 11 enters the adiabatic furnace 5 through oxygen carrier inlet 8. Reduced oxygen carrier 11 consists of reduced particles returned from the fuel reactor, with a temperature ≥900℃. Circulating ash 12 enters the adiabatic furnace 5 from the return feeder. Circulating ash 12 consists of inert solid particles, mainly composed of ash or inert carrier materials, and plays a role in heat regulation within the system. Fluidizing air enters the adiabatic furnace 5 from the fluidizing air chamber 4 via the air distribution plate 7. The fluidizing air is preheated air or oxygen-enriched air, and its flow rate is adjusted according to load requirements.
[0044] S2, oxidation reaction and heating.
[0045] The oxygen carrier 11 inside the insulated furnace 5 undergoes an oxidation reaction with the air, releasing a large amount of heat. Because the insulated furnace 5 employs an insulated design (lining with refractory material and external insulation), the heat released is primarily used to heat the oxygen carrier 11 and the circulating ash 12, raising their temperatures to the target temperature. In this embodiment, the target temperature is 950–1100°C, which satisfies the heat requirements of the fuel reactor while avoiding the risk of overheating in the air reactor 1, providing a sufficient safety margin.
[0046] S3, Material Separation and Circulation.
[0047] The oxidized oxygen carrier 11, due to its larger particle size and higher density, mainly flows downwards under bubbling fluidization conditions, exiting from the oxygen carrier outlet 9 and entering the fuel reactor to provide oxygen and heat for the fuel reaction. The circulating ash 12, due to its smaller particle size and lower density, is carried by the rising flue gas into the water-cooled membrane furnace 6. Inside the water-cooled membrane furnace 6, the circulating ash 12 undergoes convective heat exchange with the membrane water-cooled wall, and after its temperature decreases, it enters the gas-solid separator 2 with the flue gas. After separation by the gas-solid separator 2, the circulating ash 12 enters the return feeder 3 and then returns to the insulated furnace 5, forming a circulation loop.
[0048] S4. Temperature monitoring and regulation.
[0049] Temperature sensor 10 monitors the temperature of the oxidized oxygen carrier 11 flowing out of oxygen carrier outlet 9 in real time. The control system determines whether the current operating temperature is within the target temperature range based on the detection signal from temperature sensor 10. If the temperature deviates from the target range, the circulation volume of circulating ash 12 is adjusted through the coordination of ash inlet 13 and ash outlet 14. Specifically: when the measured temperature is too low, some circulating ash 12 is discharged through ash outlet 14 to reduce the circulation volume of circulating ash 12, thereby reducing the heat absorption of the water-cooled film fireplace 6 and thus increasing the temperature of the oxygen carrier 11; when the measured temperature is too high, circulating ash 12 is replenished through ash inlet 13 to increase the circulation volume of circulating ash 12, enhancing the heat absorption of the water-cooled film fireplace 6 and thus lowering the temperature of the oxygen carrier 11.
[0050] The control method provided in this application directly reflects the thermal state of the air reactor 1 and its heat supply capacity to the fuel reactor by real-time monitoring of the temperature of the oxygen carrier 11 after oxidation. The control objective is clear and the response is rapid. The heat absorption of the water-cooled film furnace 6 is changed by adjusting the circulation rate of the circulating ash 12. The adjustment method is simple and direct, with a wide adjustment range, achieving temperature control within a 30% to 100% load range without affecting the normal oxidation reaction and circulation of the oxygen carrier 11. The control logic is clear; only the circulation rate of the circulating ash 12 needs to be adjusted based on a single temperature parameter, eliminating the need for complex coordination control, making it easy to automate and operate.
[0051] In some embodiments, the control method provided in this application further includes the following steps: Reduced load operation control: When conventional load reduction operations such as reducing coal input, decreasing air volume, and reducing water supply are performed, the heat input of air reactor 1 decreases accordingly when the system is running at a reduced load. If the original circulating ash 12 circulation rate is maintained, the heat absorption of water-cooled film furnace 6 will be relatively excessive, leading to a drop in the temperature of insulated furnace 5.
[0052] At this time, if the temperature sensor 10 detects that the temperature of the oxidized oxygen carrier 11 is lower than the first temperature threshold, a portion of the circulating ash 12 is discharged from the return feeder 3 through the ash discharge port 14, reducing the circulation volume and inventory of circulating ash 12 in the system. The reduction in the circulation volume of circulating ash 12 leads to a decrease in the gas-solid concentration in the water-cooled film furnace 6, a decrease in heat absorption, a decrease in heat loss in the insulated furnace 5, and a temperature rebound. When the temperature sensor 10 detects that the temperature of the oxidized oxygen carrier 11 has rebounded to the target temperature range, the discharge of circulating ash 12 is stopped, maintaining the current circulation volume of circulating ash 12. The first temperature threshold is less than the target temperature. In this embodiment, the target temperature is 1000℃, and the first temperature threshold is 950℃.
[0053] Load ramp operation control: When conventional load-reducing operations such as increasing coal input, increasing air volume, and increasing water supply are performed, causing the system to operate at increased load, the heat input of air reactor 1 will increase accordingly. If the original circulating ash 12 circulation rate is maintained, the heat absorption of water-cooled film furnace 6 will be relatively insufficient, leading to an increase in the temperature of insulated furnace 5.
[0054] At this point, if the temperature sensor 10 detects that the temperature of the oxidized oxygen carrier 11 is higher than the second temperature threshold, circulating ash 12 is added to the return feeder 3 through the ash inlet 13, increasing the circulation volume and storage of circulating ash 12 in the system. The increase in the circulation volume of circulating ash 12 leads to an increase in the gas-solid concentration in the water-cooled film furnace 6, increasing heat absorption. Excess heat in the insulated furnace 5 is effectively absorbed, and the temperature decreases. When the temperature sensor 10 detects that the temperature of the oxidized oxygen carrier 11 has decreased to the target temperature range, the addition of circulating ash 12 is stopped, maintaining the current circulation volume of circulating ash 12. The second temperature threshold is greater than the target temperature. In this embodiment, the target temperature is 1000℃, and the second temperature threshold is 1100℃.
[0055] Based on the structure and control method of the chemical looping air reactor with wide-load operation provided in the embodiments of this application, a certain 100MW th The parameters of the chemical looping combustion system under different load conditions are shown in the table below:
[0056] As shown in the table above, by adopting the chemical looping air reactor structure and control method provided in the embodiments of this application, the temperature of the oxygen carrier 11 flowing from the air reactor 1 to the fuel reactor can be kept stable at ≥950℃ within the range of 30-100% variable load, thereby ensuring that the fuel reactor maintains a reaction temperature of ≥900℃, ensuring that the reaction of the fuel reactor proceeds effectively, and achieving stable operation of the system under wide load.
[0057] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.
Claims
1. A structure for a chemical looping air reactor operating under wide load conditions, characterized in that, The system includes an air reactor (1), a gas-solid separator (2), and a return feeder (3). The air reactor (1) has a fluidizing air chamber (4), an insulated furnace (5), and a water-cooled film furnace (6) connected sequentially from bottom to top. An air distribution plate (7) is provided between the fluidizing air chamber (4) and the insulated furnace (5). The insulated furnace (5) is provided with an oxygen carrier inlet (8) and an oxygen carrier outlet (9) arranged below the oxygen carrier inlet (8). The oxygen carrier outlet (9) is provided with a temperature sensor (10) for measuring the temperature of the oxygen carrier (11). The top of the water-cooled film fireplace (6) is connected to the inlet of the gas-solid separator (2), the solid phase outlet of the gas-solid separator (2) is connected to the inlet of the return feeder (3), the outlet of the return feeder (3) is connected to the insulated furnace (5), and the return feeder (3) is provided with an ash inlet (13) for adding circulating ash (12) into its inner cavity and an ash outlet (14) for discharging circulating ash (12); the insulated furnace (5) is filled with an oxygen carrier (11) and circulating ash (12), and the oxygen carrier (11) is in a bubbling fluidized state in the insulated furnace (5); the circulating ash (12) circulates between the air reactor (1), the gas-solid separator (2) and the return feeder (3), and the circulation volume is changed by the ash inlet (13) and the ash outlet (14) to adjust the heat absorption of the water-cooled film fireplace (6) and achieve wide load operation.
2. The structure of the chemical looping air reactor for wide-load operation according to claim 1, characterized in that, The particle size of the oxygen carrier (11) is larger than that of the circulating ash (12), and the particle size distribution range of the oxygen carrier (11) is smaller than that of the circulating ash (12).
3. The structure of the chemical looping air reactor for wide-load operation according to claim 2, characterized in that, The particle size characteristic D50 of the oxygen carrier (11) is 200-500 μm, and the particle size characteristic D50 of the recycled ash (12) is 20-100 μm.
4. The structure of the chemical looping air reactor for wide-load operation according to claim 1, characterized in that, The bottom and top of the water-cooled film fireplace chamber (6) are respectively provided with pressure taps (15), and the two pressure taps (15) are connected to the differential pressure measuring device (16) for detecting the gas-solid flow pressure drop inside the water-cooled film fireplace chamber (6).
5. The structure of the chemical looping air reactor for wide-load operation according to claim 1, characterized in that, The flow velocity of flue gas in the insulated furnace (5) is 1.5 to 5 m / s.
6. The structure of the chemical looping air reactor for wide-load operation according to claim 1, characterized in that, The gas-solid separator (2) includes a cyclone separator.
7. The structure of the chemical looping air reactor for wide-load operation according to claim 1, characterized in that, The temperature of the reduced oxygen carrier (11) entering from the oxygen carrier inlet (8) is ≥900°C, and the temperature of the oxidized oxygen carrier (11) flowing out from the oxygen carrier outlet (9) is ≥950°C.
8. A control method for a chemical looping air reactor structure operating under wide loads as described in any one of claims 1 to 7, characterized in that, include: The reduced oxygen carrier (11) enters the insulated furnace (5) from the oxygen carrier inlet (8), and the circulating ash (12) enters the insulated furnace (5) from the return feeder. The fluidizing air enters the insulated furnace (5) from the fluidizing air chamber (4) through the air distribution plate (7). The oxygen carrier (11) in the insulated furnace (5) reacts with the air to release heat, heating the oxygen carrier (11) and the circulating ash (12) to the target temperature. The oxidized oxygen carrier (11) flows out from the oxygen carrier outlet (9) and enters the fuel reactor. The circulating ash (12) is carried by the flue gas into the water-cooled film furnace (6) for heat exchange, and then returns to the insulated furnace (5) through the gas-solid separator (2) and the return feeder (3). The circulating amount of the circulating ash (12) is adjusted by the ash inlet (13) and the ash outlet (14) according to the temperature of the oxidized oxygen carrier (11) detected by the temperature sensor (10).
9. The control method according to claim 8, characterized in that, Also includes: When the load is reduced, if the temperature sensor (10) detects that the temperature of the oxidized oxygen carrier (11) is lower than the first temperature threshold, part of the circulating ash (12) is discharged from the return feeder (3) through the ash discharge port (14) until the temperature sensor (10) detects that the temperature of the oxidized oxygen carrier (11) is within the target temperature range. When the load is increased, if the temperature sensor (10) detects that the temperature of the oxidized oxygen carrier (11) is higher than the second temperature threshold, the circulating ash (12) is added to the return feeder (3) through the ash inlet (13) until the temperature sensor (10) detects that the temperature of the oxidized oxygen carrier (11) is within the target temperature range. Wherein, the first temperature threshold < the target temperature < the second temperature threshold.
10. The control method according to claim 8, characterized in that, The temperature of the reduced oxygen carrier (11) is ≥900℃, and the target temperature is 950~1100℃.