Chemical looping combustion carbon capture system

Abstract

The utility model belongs to the chemical chain carbon capture technology field, concretely is a kind of chemical chain combustion carbon capture system. In a kind of chemical chain combustion carbon capture system, the "L" type fuel reactor has been adopted, and the length ratio of horizontal section hearth (203) and vertical section hearth (204) in the reactor is designed as 3-20 according to unit capacity;The width-depth ratio of horizontal section hearth (203) is 3-10;The height of horizontal section hearth (203) is 2-4 meters;The gas flow velocity of dense phase zone in the lower part of "L" type fuel reactor (2) is 2-5 meters per second, and the upper part lifting section gas flow velocity is 7-10 meters per second.The utility model prolongs the effective residence time of fuel in hot fuel reactor by adopting special fuel reactor structure and high-concentration CO2 flue gas recirculation, reduces the amount of water vapor, reduces the bed pressure operation, realizes the efficient and low-cost operation of chemical chain combustion carbon capture system.

Description

[0001] Technical Field This invention belongs to the field of chemical chaining carbon capture technology, specifically a chemical chaining combustion carbon capture system.

[0002] Background Technology CO2 emissions from fossil fuel combustion have accelerated global warming, drawing worldwide attention. When considering the use of abundant coal resources, countries are placing particular emphasis on research into carbon reduction technologies and urgently need to develop strategies to reduce global CO2 emissions. Therefore, ultra-low emission control of pollutants from solid fuel combustion and carbon capture are crucial for achieving my country's "dual-carbon" strategic goals. Chemical looping combustion technology, as a new generation of carbon capture technology, separates nitrogen and carbon dioxide at the source of the combustion reaction, allowing for the collection of high-purity carbon dioxide at the fuel reactor outlet. This significantly reduces carbon capture costs and represents a highly promising new carbon capture technology. Traditional chemical looping fuels react slowly in fuel reactors, requiring a long time for carbon conversion. Furthermore, fuel reactors use steam as the gasification medium, resulting in high energy consumption, high water consumption, and low economic efficiency.

[0003] The residence time of fuel in the fuel reactor is a crucial parameter. Insufficient residence time triggers a series of adverse effects, severely restricting the efficiency, economy, and stability of the entire CLC system. The most direct and significant impact is the incomplete conversion of fuel. The fuel reactor in a CLC is a gas-solid heterogeneous reaction process; the fuel (usually gaseous hydrocarbons or gasified syngas) needs to make sufficient contact with solid oxygen carrier particles and undergo a reduction reaction. Insufficient residence time directly leads to low fuel conversion rate, impaired combustion efficiency, and decreased CO2 capture purity, resulting in the failure of core functions. Indirectly, it causes incomplete oxygen carrier reduction, system thermal imbalance, carbon deposition and sintering, and increased material loss, leading to operational stability problems. Ultimately, in engineering terms, this manifests as increased reactor design constraints, greater operational difficulty, and escalating operating costs.

[0004] Currently, most fuel reactors using patented chemical looping combustion technologies employ conventional bubbling bed structures. They extend the fuel residence time by increasing the cross-sectional area of ​​the lower part of the reactor to reduce the airflow velocity and by increasing the reactor height. However, the effective residence time remains relatively short, leading to incomplete fuel pyrolysis, gasification, and combustion reactions, insufficient oxygen carrier reduction, and excessively high combustible gas content in the flue gas exiting the reactor. The reactor structure fails to meet ideal requirements. Furthermore, existing chemical looping technologies often operate at high bed pressures (nearly 100 kPa), resulting in high blower energy consumption and uneconomical operation. Therefore, further technological improvements are needed to reduce operating costs and increase efficiency. Utility Model Content

[0005] The purpose of this invention is to provide a chemical looping combustion carbon capture system to address the problems existing in the prior art. In this system, by employing a specialized fuel reactor structure and high-concentration CO2 flue gas recirculation, the effective residence time of fuel in the fuel reactor is extended, water vapor consumption is reduced, bed pressure is lowered, and efficient and low-cost operation of the chemical looping combustion carbon capture system is achieved. The fuel reactor of this application adopts a specialized "L"-shaped structure. The fuel is fully mixed with the oxygen carrier in the "L"-shaped fuel reactor and tumbles towards the discharge overflow end, extending the residence time of the fuel in the fuel reactor, solving the problem of insufficient reaction between fuel and oxygen carrier, and improving carbon conversion rate. The specialized "L"-shaped structure and high-concentration CO2 flue gas recirculation allow the material holding capacity and material throughput of the fuel reactor to be met by the size of the lower bed cross-section, reducing bed pressure operation, fan power consumption, and system energy consumption. The high-concentration CO2 flue gas recirculated from the fuel reactor replaces the water vapor of the fluidizing medium in the fuel reactor and return feeder of existing patented technologies, solving the problems of high water vapor consumption and high failure rate, and achieving high-concentration enrichment of CO2 in the flue gas. This paper provides a method for using the chemical looping combustion carbon capture system, enabling efficient and low-cost operation of the system and significantly reducing carbon capture costs.

[0006] To achieve the purpose of this utility model, the specific technical solution adopted is as follows: A chemical looping combustion carbon capture system employs an "L"-shaped fuel reactor (FR). The "L"-shaped fuel reactor is an elongated, flat, L-shaped fluidized bed structure, including a bottom fuel reactor air chamber, a fuel reactor air distribution plate mounted on the air chamber, a horizontal furnace section mounted on the air distribution plate, and a vertical furnace section connected to and perpendicular to the horizontal furnace section. This reactor features a longer horizontal furnace section, increasing the residence time of the oxygen carrier and fuel in the FR, and prolonging the reaction time between the oxygen carrier and fuel, thereby improving the fuel carbon conversion rate.

[0007] Furthermore, in the aforementioned chemical looping combustion carbon capture system, the ratio of the horizontal to vertical furnace lengths in the "L"-shaped fuel reactor is designed to be 3-20 based on the unit capacity. The "L"-shaped fuel reactor features a longer horizontal furnace section, increasing the residence time of the oxygen carrier and fuel in the fuel flow rate (FR), extending the reaction time between the oxygen carrier and fuel, and improving the fuel carbon conversion rate. The height of the horizontal furnace section can be designed according to the chemical looping unit capacity, ideally between 2-4 meters (specifically 2, 3, or 4 meters, etc.; the height should not be too high to prevent significant gas-solid stratification).

[0008] Furthermore, in the aforementioned chemical looping combustion carbon capture system, the airflow velocity in the horizontal section of the "L"-shaped fuel reactor is 2-5 m / s (if the velocity is too low, it will lead to insufficient and intense mixing), ensuring sufficient contact between the fuel and the syngas produced from the fuel and the oxygen carrier for complete reaction. The airflow velocity of FR2 can be controlled by adjusting the recirculation rate of the CO2 flue gas.

[0009] Furthermore, in the aforementioned chemical looping combustion carbon capture system, the airflow velocity in the dense phase zone at the bottom of the "L"-shaped fuel reactor is 2-5 m / s, and the airflow velocity in the upper lifting section is 7-10 m / s. The width-to-depth ratio of the horizontal furnace section is 3-10; in actual engineering FR reactors, the width-to-depth ratio of the horizontal furnace section 203 can be flexibly selected according to the unit capacity.

[0010] Furthermore, the fuel reactor's air chamber consists of N (or more) independent partitioned air chambers, each with individually adjustable and controllable airflow. This avoids uneven airflow distribution due to bed pressure differences, which can lead to poor fluidization. N > 1 (e.g., 3, 4, 5, or 6, etc.). The fuel reactor's air distribution plate has a 2-5° slope; the lowest point of the air distribution plate is located at the temporary or emergency discharge port, facilitating smooth flow of solid materials on the air distribution plate.

[0011] As a preferred embodiment, the chemical looping combustion carbon capture system of this utility model specifically includes an air reactor (AR), an "L"-shaped fuel reactor (FR), an AR cyclone separator, an FR cyclone separator, an AR return feeder, an AR return leg, an FR return feeder, an FR return leg, return feeders from FR2 to AR1, an FR-side heat exchanger, an FR-side preheater, an FR-side dust collector, an AR-side heat exchanger, an AR-side preheater, an AR-side dust collector, an induced draft fan, a chimney, a recirculation fan, an FR-side flue gas recirculation system, and a Roots blower. in, The air reactor is a device for oxygen carrier oxidation reaction, including a supplementary original oxygen carrier and an oxygen carrier supplied from FR2, with air as the oxidation medium, and oxidation in AR1; The upper outlet of the air reactor is divided into two paths. One path is connected to the "L"-shaped fuel reactor through the AR cyclone separator and the AR return leg on the AR return device to receive the oxygen carrier sent from the "L"-shaped fuel reactor; the other path is connected to the AR side heat exchanger. The “L” type fuel reactor is connected to the lower part of the air reactor through the return feeders from FR2 to AR1; The upper part of the "L"-shaped fuel reactor is connected in sequence to the FR cyclone separator and the FR return leg of the FR return feeder before returning to the lower part of the "L"-shaped fuel reactor to form a cycle; The FR cyclone separator is connected in sequence to the FR side heat exchanger, the FR side preheater, and the FR side dust collector before being connected to the compression combustion system. The FR-side dust collector is reconnected to the FR-side preheater via a recirculation fan to form a cycle. The AR-side heat exchanger is connected in sequence to the AR-side preheater, AR-side dust collector, induced draft fan and chimney; The FR-side preheater is connected to the FR-side flue gas recirculation system and then connected to the FR return feeder, the return feeders from FR2 to AR1, and the AR return feeder via Roots blowers; the FR-side preheater is connected to the "L"-type fuel reactor.

[0012] Preferably, in the chemical looping combustion carbon capture system, the air reactor is a fluidized bed structure, including a bottom air chamber, an air distribution plate installed on the air chamber, and a reactor furnace set on the air distribution plate.

[0013] Preferably, in the chemical loop combustion carbon capture system, a water replenishment device is installed at the FR side preheater, and the water vapor content in the recirculated flue gas is adjusted by spraying water as needed.

[0014] A method for capturing carbon from chemically looping combustion using the aforementioned chemically looping combustion carbon capture system includes the following steps: The oxygen carrier is directly added to the lower part of the air reactor, where it is oxidized and activated. Then, it undergoes an oxidation reaction with the oxygen carrier from the "L"-shaped fuel reactor in the air reactor, with air as the oxidation medium. The oxidized oxygen carrier in the air reactor is separated by an AR cyclone separator and sent to the "L"-shaped fuel reactor by an AR return feeder. The oxygen carrier simultaneously provides the "L"-shaped fuel reactor with the heat required for the fuel reaction. The flue gas generated in the air reactor is discharged through a chimney after being subjected to tail heat exchange and dust removal. Solid fuel is added from the FR return leg of the FR return feeder, and the fuel enters the "L"-shaped fuel reactor along with the FR return material; FR2 is the fuel reactor, where the fuel is preheated by the high-temperature return material in the FR return leg; the fuel reacts with the oxygen carrier in the "L"-shaped fuel reactor to generate CO2, water vapor, etc.; the generated flue gas passes through a heat exchanger and a dust collector, part of which is used as recirculated flue gas, and the other part is sent to the compression and purification system after denitrification and desulfurization to achieve high concentration enrichment of CO2.

[0015] Furthermore, the return feed from the air reactor and the return feed from the "L"-shaped fuel reactor are added to the lower part of the "L"-shaped fuel reactor from different locations, and the fuel enters FR2 along with the FR return feed. The fuel is preheated by the high-temperature return feed in the return feed leg, shortening the preheating time of the fuel in FR2, which is conducive to the full reaction of the fuel in FR2 and improves the carbon conversion rate of the fuel. The return feed temperature in the FR return feeder is in the range of 800~900℃, and the fuel is not easily pyrolyzed in the return feed leg. The reasonable design of the lower height of the FR2 reactor ensures that the solid fuel can overcome the back pressure in the furnace and be fed smoothly.

[0016] Preferably, the supplementary oxygen carrier is directly added to the lower part of the AR1 reactor for oxidation and activation in the AR1 reactor.

[0017] Preferably, the oxygen carrier reduced in the "L"-shaped fuel reactor is fed into the lower part of the air reactor (at a certain height) by overflow in the "L"-shaped fuel reactor, and is oxidized and activated in the AR1 reactor.

[0018] Preferably, during the process of the oxygen carrier overflowing from FR1 into AR2, the bottom of the middle conveying channel is equipped with a wind cap to loosen the material and ensure smooth flow of the material in the channel.

[0019] Preferably, the fuel reacts with the oxygen carrier in the "L"-shaped fuel reactor, and the resulting flue gas, after passing through a heat exchanger and a dust collector, enters the "L"-shaped fuel reactor, AR return feeder, and FR return feeder respectively as a fluidizing medium; the other part is also divided into two paths. One path of the recirculated flue gas, after denitrification and desulfurization, is preheated by a circulating fan (pressure head of about 25 kPa) and sent to the air chamber of the fuel reactor, effectively solving the problem of needing heat tracing when using water vapor as a fluidizing medium; the other path of the recirculated flue gas, before being preheated by the preheater, is sent by a high-pressure Roots blower (pressure head of about 60 kPa) to the AR return feeder, FR return feeder, and the return feeder from FR2 to AR1 respectively, effectively solving the problem of needing heat tracing when using water vapor as a fluidizing medium.

[0020] Preferably, the flue gas from the "L"-shaped fuel reactor (connected sequentially to the FR-side heat exchanger, preheater, and dust collector) is cooled by the FR-side heat exchanger and preheater, and then dusted by the dust collector. Part of the flue gas enters the compression and purification system for carbon capture, while the other part is sent to the preheater via a circulating fan (connected to the preheater and then to the "L"-shaped fuel reactor) to be preheated into recirculated flue gas. This recirculated flue gas is used as fluidization air for the "L"-shaped fuel reactor. Before preheating in the preheater, a portion of the recirculated flue gas is extracted by a (set) Roots blower (connected to the AR return feeder, FR return feeder, and return feeders from FR2 to AR1) to be used as fluidization air for the AR return feeder, FR return feeder, and return feeders from FR2 to AR1.

[0021] FR2 uses recirculated flue gas as the fluidizing medium, without using steam, and does not have a dedicated steam generator or feed device, effectively avoiding the problems of water vapor condensation in the wind chamber and material agglomeration in the area near the air distribution plate at the bottom of the reactor due to insufficient heating.

[0022] Preferably, the chemical looping combustion of solid fuel (coal or biomass) and natural gas in FR2 produces a large amount of water vapor. The recirculated flue gas is the flue gas from FR2, which contains fuel moisture and water generated by fuel reaction. The water vapor content is relatively high, and the specific range is related to the fuel composition, generally in the range of 15-40%, which can meet the water vapor requirements of FR2 fuel reaction.

[0023] Preferably, a water replenishment device is installed on the recirculated flue gas side at the preheater. If the water vapor content in the flue gas from FR2 is insufficient to meet the water vapor requirements of the FR2 reaction, water can be sprayed into the recirculated flue gas during preheating in the preheater. The sprayed water is vaporized into water vapor in the recirculated flue gas to replenish the water vapor required for the FR2 reaction.

[0024] Preferably, considering the working environment of the recirculation fan and to reduce wear, the recirculated flue gas is taken from the flue gas after the dust collector. The flue gas temperature before entering the preheater is in the range of 100~180℃, and the temperature of the recirculated flue gas after being heated by the preheater is in the range of 300~700℃. The specific temperature range can be designed as needed.

[0025] This application adopts the above-mentioned fuel reactor structure in the chemical loop combustion system to extend the residence time of fuel in the fuel reactor, allowing the fuel to fully react with the oxygen carrier and improve the carbon conversion rate; and uses the high-concentration CO2 flue gas from the fuel reactor as recirculated flue gas to replace water vapor as the fluidizing medium of the fuel reactor and return feeder, reducing the amount of water vapor used and the failure rate, lowering operating costs and improving system efficiency.

[0026] Compared with the prior art, the main advantages of this utility model are as follows: (1) The high-concentration CO2 flue gas from FR2 is recycled to achieve high-concentration enrichment of CO2 through chemical loop combustion, thereby achieving the goal of "low-carbon" development of clean energy in the thermal power generation industry and achieving high efficiency, energy saving and carbon reduction.

[0027] (2) High-concentration CO2 flue gas from FR2 is recirculated to replace the water vapor in the fluidizing medium of FR2 and AR return feeder and FR return feeder, which effectively avoids the problem of water vapor condensation in the wind chamber and material agglomeration in the area near the air distribution plate at the bottom of the reactor due to insufficient heating.

[0028] (3) The flue gas from FR2 is recirculated. The recirculated flue gas contains a certain amount of water vapor. Only a small amount of water vapor needs to be added or no additional water vapor is needed to meet the requirements of chemical chain combustion, reduce water vapor consumption, solve the problems of high water vapor consumption and high failure rate, reduce operating costs, and improve unit efficiency.

[0029] (4) FR2 has an “L”-shaped flat and long structure with a longer horizontal section of fluidized bed, which increases the residence time of oxygen carrier and fuel in FR, prolongs the reaction time of oxygen carrier and fuel contact, and improves the carbon conversion rate of fuel.

[0030] (5) Solid fuels (coal, biomass, etc.) are added from the return leg of the FR return feeder. The fuel is preheated by the high temperature return feed in the return leg, which shortens the preheating time of the fuel in FR2, which is conducive to the full reaction of the fuel in FR2 and improves the carbon conversion rate of the fuel.

[0031] (6) The AR return feeder, FR return feeder, and FR2 to AR1 return feeders use recirculated flue gas as the fluidizing medium. The circulating flue gas is extracted before preheating in the preheater by a high-pressure Roots blower (pressure head about 60 kPa), which effectively solves the problem of needing heat tracing when using steam as the fluidizing medium.

[0032] (7) FR2 uses recirculated flue gas as the fluidizing medium, not steam. It does not have a dedicated steam generator or injection device. Instead, a water supply device is installed on the recirculated flue gas side of the preheater for adjusting and reserving water vapor content in the recirculated flue gas. This saves steam and reduces operating costs. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a chemical looping combustion carbon capture system according to the present invention; Figure 2 This is a schematic diagram of an "L"-shaped fuel reactor. Among them, 1-Air reactor (AR), 2-"L" type fuel reactor (FR), 3-AR cyclone separator, 4-FR cyclone separator, 5-AR return feeder, 51-AR return leg, 6-FR return feeder, 61-FR return leg, 7-FR to AR return feeder, 8-FR side heat exchanger, 9-preheater, 10-FR side dust collector, 11-AR side heat exchanger, 12-AR side preheater, 13-AR side dust collector, 14-induced draft fan, 15-chimney, 16-recirculation fan, 17-FR side flue gas recirculation system, 18-water makeup device, 19-Roots blower, 101-air chamber, 102-air distribution plate, 103-reactor furnace, 201-fuel reactor air chamber, 202-fuel reactor air distribution plate, 203-horizontal section furnace, 204-vertical section furnace. Detailed Implementation

[0034] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0035] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] In this utility model, some conventional operating equipment, devices and components have been omitted or only briefly described.

[0038] Unless otherwise specified in the examples, the conditions shall be performed in accordance with the standard conditions or the conditions recommended by the manufacturer.

[0039] Example 1: A chemical looping combustion carbon capture system employs an "L"-shaped fuel reactor (FR) 2. The "L"-shaped fuel reactor 2 is an "L"-shaped, elongated fluidized bed structure, including a bottom fuel reactor air chamber 201, a fuel reactor air distribution plate 202 mounted on the air chamber 201, a horizontal furnace section 203 mounted on the air distribution plate 202, and a vertical furnace section 204 connected to and perpendicular to the horizontal furnace section 203. The reactor features a longer horizontal furnace section 203, increasing the residence time of the oxygen carrier and fuel in the FR, and prolonging the reaction time between the oxygen carrier and fuel, thereby improving the fuel carbon conversion rate.

[0040] Furthermore, in the "L"-shaped fuel reactor, the length ratio of the horizontal section furnace 203 to the vertical section furnace 204 is designed to be 10 based on the unit capacity. The "L"-shaped fuel reactor features a longer horizontal section furnace, increasing the residence time of the oxygen carrier and fuel in the FR (reacting flow rate), extending the reaction time of contact between the oxygen carrier and fuel, and improving the fuel carbon conversion rate. The height of the horizontal section furnace 203 can be designed according to the capacity of the chemical looping unit, preferably 2-4 meters (the height should not be too high to prevent obvious gas-solid stratification).

[0041] Furthermore, the gas flow velocity in the horizontal section of the "L"-shaped fuel reactor 2 is 2-5 m / s (if the velocity is too low, it will lead to insufficient and intense mixing), ensuring sufficient contact between the fuel and the syngas produced from the fuel and the oxygen carrier for complete reaction. The gas flow velocity of FR2 can be controlled by adjusting the recirculation ratio of the CO2 flue gas.

[0042] Furthermore, the airflow velocity in the dense phase zone at the bottom of the "L"-shaped fuel reactor 2 is 2-5 m / s, and the airflow velocity in the upper lifting section is 7-10 m / s. The width-to-depth ratio of the horizontal furnace section 203 is 6. In actual engineering FR reactors, the width-to-depth ratio of the horizontal furnace section 203 can be flexibly selected according to the unit capacity.

[0043] Furthermore, the fuel reactor air chamber 201 consists of five independently partitioned air chambers, each with individually adjustable and controllable airflow. This avoids uneven airflow distribution due to bed pressure differences, which could lead to poor fluidization. The fuel reactor air distributor 202 has a 3° inclined slope; its lowest point is located at the temporary or emergency discharge port, facilitating smooth flow of solid materials on the air distributor.

[0044] Example 2: Based on Example 1, a chemical looping combustion carbon capture system is shown in the schematic diagram below. Figure 1 and Figure 2 As shown. The specific system includes an air reactor (AR) 1, an "L"-shaped fuel reactor (FR) 2, an AR cyclone separator 3, an FR cyclone separator 4, an AR return feeder 5, an AR return leg 51, an FR return feeder 6, an FR return leg 61, a return feeder from FR2 to AR1 7, an FR-side heat exchanger 8, an FR-side preheater 9, an FR-side dust collector 10, an AR-side heat exchanger 11, an AR-side preheater 12, an AR-side dust collector 13, an induced draft fan 14, a chimney 15, a recirculation fan 16, an FR-side flue gas recirculation system 17, and a Roots blower 19. in, Air reactor 1 is a device for oxygen carrier oxidation reaction, including a supplemented original oxygen carrier and an oxygen carrier supplied from FR2. The oxidation medium is air, and oxidation occurs in AR1. The upper outlet of the air reactor 1 has two paths. One path is connected to the "L"-shaped fuel reactor 2 through the AR cyclone separator 3 and the AR return leg 51 on the AR return device 5 to receive the oxygen carrier sent from the "L"-shaped fuel reactor 2. The other path is connected to the AR side heat exchanger 11. The “L”-shaped fuel reactor 2 is connected to the lower part of the air reactor 1 via the return feeder 7 from FR2 to AR1; The upper part of the “L”-shaped fuel reactor 2 is connected in sequence to the FR return leg 61 of the FR cyclone separator 4 and the FR return feeder 6, and then returns to the lower part of the “L”-shaped fuel reactor 2 to form a cycle. The FR cyclone separator 4 is connected in sequence to the FR side heat exchanger 8, the FR side preheater 9, and the FR side dust collector 10, and then to the compression combustion system. The FR-side dust collector 10 is reconnected to the FR-side preheater 9 via the recirculation fan 16 to form a cycle; AR side heat exchanger 11 is connected in sequence to AR side preheater 12, AR side dust collector 13, induced draft fan 14 and chimney 15; The FR side preheater 9 is connected to the FR side flue gas recirculation system 17 and then connected to the FR return feeder 6, the FR2 to AR1 return feeder 7 and the AR return feeder 5 respectively through the Roots blower 19; the FR side preheater 9 is connected to the "L" type fuel reactor 2.

[0045] In the aforementioned chemical looping combustion carbon capture system, the air reactor 1 is a fluidized bed structure, including a bottom air chamber 101, an air distribution plate 102 installed on the air chamber 101, and a reactor furnace 103 disposed on the air distribution plate 102.

[0046] The fluidizing medium in AR1 is air preheated by the AR-side preheater 12. The oxygen carrier is oxidized in AR1 and then separated by the AR cyclone separator 3. It is then sent to FR2 by the AR return feeder 5, providing heat to FR2. The high-temperature flue gas in AR1 passes through the AR cyclone separator 3, then exchanges heat with the AR-side steam-water heat exchanger 11 and the AR-side preheater 12. After being dusted by the AR-side dust collector 13, it is discharged through the chimney 15 by the induced draft fan 14.

[0047] FR2 is a fuel reactor in which fuel reacts with oxygen carrier to produce CO2, water vapor, etc. After the flue gas is removed by the FR side heat exchanger 8, FR side preheater 9 and FR side dust collector 10, part of it is used as recirculated flue gas and part of it is sent to the compression and purification system to achieve high concentration enrichment of CO2.

[0048] In the aforementioned chemical looping combustion carbon capture system, a water replenishment device 18 is installed at the FR side preheater 9, and the water vapor content in the recirculated flue gas is adjusted by spraying water as needed.

[0049] Example 3: Based on Examples 1 and 2, a method for capturing carbon from chemically looping combustion using the aforementioned chemically looping combustion carbon capture system includes the following steps: The oxygen carrier is directly added to the lower part of the air reactor 1, where it is oxidized and activated. Then, it undergoes an oxygen carrier oxidation reaction with the oxygen carrier from the "L"-shaped fuel reactor 2 in the air reactor 1, where the oxidation medium is air. The oxygen carrier oxidized in the air reactor 1 is separated by the AR cyclone separator 3 and sent to the "L"-shaped fuel reactor 2 by the AR return feeder 5. The oxygen carrier simultaneously provides the "L"-shaped fuel reactor 2 with the heat required for the fuel reaction. The flue gas generated in the air reactor 1 is discharged through the chimney 15 after tail heat exchange and dust removal. Solid fuel is added from the FR return leg 61 of the FR return feeder 6, and the fuel enters the "L"-shaped fuel reactor 2 together with the FR return material; FR2 is the fuel reactor, where the fuel is preheated by the high-temperature return material in the FR return leg 61; the fuel reacts with the oxygen carrier in the "L"-shaped fuel reactor 2 to generate CO2, water vapor, etc.; the generated flue gas passes through a heat exchanger and a dust collector, part of which is used as recirculated flue gas, and the other part is sent to the compression and purification system after denitrification and desulfurization to achieve high concentration enrichment of CO2.

[0050] Furthermore, the return material from air reactor 1 and the return material from the "L"-shaped fuel reactor 2 are added to the lower part of the "L"-shaped fuel reactor 2 from different positions, and the fuel enters FR2 together with the FR return material. The fuel is preheated by the high-temperature return material in return material leg 61, which shortens the preheating time of the fuel in FR2, facilitates the full reaction of the fuel in FR2, and improves the carbon conversion rate of the fuel. The return material temperature in FR return material 6 is in the range of 800~900℃, and the fuel is not easily pyrolyzed in return material leg 7. The reasonable design of the lower height of the FR2 reactor ensures that the solid fuel can overcome the back pressure in the furnace and be fed smoothly.

[0051] The new oxygen carrier is added directly to the bottom of the AR1 reactor for oxidation and activation.

[0052] The reduced oxygen carrier in the "L"-shaped fuel reactor 2 is fed into the lower part of the air reactor 1 by overflow in the "L"-shaped fuel reactor 2 (at a certain height), and is oxidized and activated in the AR1 reactor.

[0053] During the process of the oxygen carrier overflowing from FR1 into AR2, the bottom of the conveying channel is equipped with a wind cap to loosen the material and ensure smooth flow of the material in the channel.

[0054] Fuel reacts with oxygen carrier in L-shaped fuel reactor 2, and the resulting flue gas, after passing through heat exchanger and dust collector, enters L-shaped fuel reactor 2, AR return feeder 5, and FR return feeder 6 as fluidizing medium. Another part is also divided into two paths. One path of recirculated flue gas, after denitrification and desulfurization, is preheated by circulating fan 16 (pressure head approximately 25 kPa) and preheated by preheater 9 before being sent to fuel reactor air chamber 201, effectively solving the problem of needing heat tracing when using water vapor as fluidizing medium. The other path of recirculated flue gas, before being preheated by preheater 9, is sent by high-pressure Roots blower 19 (pressure head approximately 60 kPa) to AR return feeder 5, FR return feeder 6, and FR2 to AR1 return feeder 7, effectively solving the problem of needing heat tracing when using water vapor as fluidizing medium.

[0055] The flue gas from the “L”-type fuel reactor 2 is cooled by the FR side heat exchanger 8 and preheater 9, and then dusted by the dust collector 10. Part of it enters the compression and purification system to achieve carbon capture, while the other part is sent to the preheater 9 through the circulating fan 16 to become recirculated flue gas. This recirculated flue gas is used as the fluidization air for the “L”-type fuel reactor 2. Before preheating in the preheater 9, a portion of the recirculated flue gas is extracted by the Roots blower 19 to be used as the fluidization air for the AR return feeder 5, FR return feeder 6, and the return feeder 7 from FR2 to AR1.

[0056] FR2 uses recirculated flue gas as the fluidizing medium, without using steam, and does not have a dedicated steam generator or feed device, effectively avoiding the problems of water vapor condensation in the wind chamber and material agglomeration in the area near the air distribution plate at the bottom of the reactor due to insufficient heating.

[0057] Solid fuels (coal or biomass) and natural gas undergo chemical looping combustion in FR2, producing a large amount of water vapor. The recirculated flue gas is the flue gas from FR2, which contains fuel moisture and water generated by the fuel reaction. The water vapor content is relatively high, with the specific range depending on the fuel composition, generally in the range of 15-40%, which can meet the water vapor requirements of the FR2 fuel reaction.

[0058] Preferably, a water replenishment device 18 is provided on the recirculated flue gas side at the preheater 9. If the water vapor content in the flue gas coming out of FR2 is insufficient to meet the water vapor requirements of the FR2 reaction, water can be sprayed into the recirculated flue gas during preheating in the preheater 9. The sprayed water is vaporized into water vapor in the recirculated flue gas to replenish the water vapor required for the FR2 reaction.

[0059] Preferably, considering the working environment of the recirculation fan 16 and to reduce wear, the recirculated flue gas is taken from the flue gas after the dust collector. The flue gas temperature before entering the preheater 9 is in the range of 100~180℃, and the temperature of the recirculated flue gas after being heated by the preheater 9 is in the range of 300~700℃. The specific temperature range can be designed as needed.

[0060] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0061] The background section is provided to generally present the context of this utility model. The work of the currently named inventors, the work to the extent described in this background section, and aspects described in this section that did not constitute prior art at the time of filing are neither expressly nor impliedly acknowledged as prior art to this utility model.

Claims

1. A chemical looping combustion carbon capture system, characterized in that, The system employs an "L"-shaped fuel reactor (2); the "L"-shaped fuel reactor (2) is an "L"-shaped flat elongated fluidized bed structure, including a fuel reactor air chamber (201) at the bottom, a fuel reactor air distribution plate (202) set on the fuel reactor air chamber (201), a horizontal section furnace (203) set on the fuel reactor air distribution plate (202), and a vertical section furnace (204) connected to and perpendicular to the horizontal section furnace (203).

2. The chemical looping combustion carbon capture system according to claim 1, characterized in that, The length ratio of the horizontal section furnace (203) to the vertical section furnace (204) is designed to be 3-20 according to the unit capacity; the width-to-depth ratio of the horizontal section furnace (203) is 3-10; and the height of the horizontal section furnace (203) is 2-4 meters.

3. The chemical looping combustion carbon capture system according to claim 1, characterized in that, The fuel reactor air chamber (201) consists of N independent partitioned air chambers, and the air volume of each small air chamber can be adjusted and controlled individually, where N>1.

4. The chemical looping combustion carbon capture system according to claim 1, characterized in that, The fuel reactor air distribution plate (202) is provided with a slope of 2-5°; the lowest point of the fuel reactor air distribution plate (202) is set at the temporary or emergency discharge port.

5. A chemical looping combustion carbon capture system, characterized in that, The system includes an air reactor (1), an "L"-shaped fuel reactor (2), an AR cyclone separator (3), an FR cyclone separator (4), an AR return feeder (5), an AR return leg (51), an FR return feeder (6), an FR return leg (61), a return feeder from FR2 to AR1 (7), an FR side heat exchanger (8), an FR side preheater (9), an FR side dust collector (10), an AR side heat exchanger (11), an AR side preheater (12), an AR side dust collector (13), an induced draft fan (14), a chimney (15), a recirculation fan (16), an FR side flue gas recirculation system (17), and a Roots blower (19). in, The air reactor (1) is a device for the oxidation reaction of oxygen carrier, including the supplemented original oxygen carrier and the oxygen carrier sent from the "L" type fuel reactor (2), with air as the oxidation medium, and oxidation in the air reactor (1); The upper outlet of the air reactor (1) has two paths. One path is connected to the "L" type fuel reactor (2) through the AR cyclone separator (3) and the AR return leg (51) on the AR return device (5) to receive the oxygen carrier sent from the "L" type fuel reactor (2); the other path is connected to the AR side heat exchanger (11). The "L"-shaped fuel reactor (2) is connected to the lower part of the air reactor (1) via the return feeder (7) from FR2 to AR1; The upper part of the "L"-shaped fuel reactor (2) is connected in sequence to the FR return leg (61) of the FR cyclone separator (4) and the FR return feeder (6) and then returns to the lower part of the "L"-shaped fuel reactor (2) to form a cycle; The FR cyclone separator (4) is connected in sequence to the FR side heat exchanger (8), the FR side preheater (9), and the FR side dust collector (10), and then to the compression combustion system. The FR side dust collector (10) is reconnected to the FR side preheater (9) via the recirculation fan (16) to form a cycle; The AR-side heat exchanger (11) is connected in sequence to the AR-side preheater (12), the AR-side dust collector (13), the induced draft fan (14), and the chimney (15); The FR side preheater (9) is connected to the FR side flue gas recirculation system (17) and then connected to the FR return feeder (6), the FR2 to AR1 return feeder (7) and the AR return feeder (5) respectively via the Roots blower (19); the FR side preheater (9) is connected to the "L" type fuel reactor (2).

6. The chemical looping combustion carbon capture system according to claim 5, characterized in that, The air reactor (1) is a fluidized bed structure, including a bottom air chamber (101), an air distribution plate (102) installed on the air chamber (101), and a reactor furnace (103) set on the air distribution plate (102); the "L"-shaped fuel reactor (2) is connected to the reactor furnace (103) at the bottom of the air reactor (1) through the return feeder (7) from FR2 to AR1.

7. The chemical looping combustion carbon capture system according to claim 5, characterized in that, A water supply device (18) is installed at the FR side preheater (9) to adjust the water vapor content in the recirculated flue gas by spraying water as needed.

8. The chemical looping combustion carbon capture system according to claim 5, characterized in that, The return material from the air reactor (1) and the return material from the "L"-shaped fuel reactor (2) are added to the lower part of the "L"-shaped fuel reactor (2) from two different locations.

9. The chemical looping combustion carbon capture system according to claim 8, characterized in that: The reduced oxygen carrier in the "L"-shaped fuel reactor (2) is fed into the lower part of the air reactor (1) by overflow in the "L"-shaped fuel reactor (2); the bottom of the conveying channel in the middle of the overflow feeding into the air reactor (1) is loosened by a wind cap.

10. The chemical looping combustion carbon capture system according to claim 8, characterized in that: After being cooled by the FR side heat exchanger (8) and preheater (9) and connected to the dust collector (10) in sequence, part of the fuel reactor (2) enters the compression purification system to achieve carbon capture, and the other part enters the "L" type fuel reactor (2) after being connected to the preheater (9) through the circulating fan (16). Before being preheated by the preheater (9), the fuel reactor (2) is connected to the AR return feeder (5), FR return feeder (6), and FR2 to AR1 return feeder (7) through the Roots blower (19).

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