Calcium-based thermochemical energy storage system and method coupled with flue gas direct carbon capture system

Abstract

The invention belongs to the field of thermochemical energy storage, and discloses a calcium-based thermochemical energy storage system and method coupled with a flue gas direct carbon capture system, and the calcium-based thermochemical energy storage system comprises a flue gas calcination reaction system, a CO2 collection system and the flue gas direct carbon capture system; a material inlet of the flue gas calcination reaction system is connected with a material outlet of the flue gas direct carbon capture system, a material outlet of the flue gas calcination reaction system is connected with a material inlet of the flue gas direct carbon capture system, and an inlet of the CO2 collection system is connected with exhaust gas of the flue gas calcination reaction system; the flue gas calcination reaction system is used for calcining calcium carbonate by using high-temperature flue gas so as to decompose calcium oxide and carbon dioxide to realize heat storage; the carbon dioxide collecting system is used for collecting and storing carbon dioxide; the flue gas direct carbon capture system is used for carrying out carbonation reaction on the desulfurized flue gas and calcium oxide to generate calcium carbonate and realize heat release; the storage and release process is independently carried out, the system design is simple, and the flexibility is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermochemical energy storage, and particularly relates to a calcium-based thermochemical energy storage system and method coupled with a flue gas direct carbon capture system. Background Technique

[0002] Thermochemical heat storage technology is currently the most functionally potential heat storage technology route. It uses the thermal efficiency of chemical reactions to store heat energy such as solar thermal energy, geothermal energy, industrial waste heat, and low-grade waste heat in the form of chemical energy in a gas stream, and releases heat through chemical reactions when needed. It has a large energy density, can achieve the effect of heat quality improvement, and the materials are convenient to store, easy to transport over long distances and for long periods, with small heat losses.

[0003] Currently, CaO / CaCO3 is a commonly used thermochemical energy storage system in the field of thermochemical heat storage. It belongs to a high-temperature cycle process. When applying the CaO / CaCO3 thermochemical energy storage system to the field of flue gas direct carbon capture, due to the high calcination reaction temperature of the material, the heat storage process needs to take into account the collection of calcination products and the indirect heat exchange process, while the heat release process requires the direct contact reaction of low-concentration flue gas with the material, making the equipment structure complex and it is difficult to balance the calcination reaction heat and carbonation reaction heat of the material. Summary of the Invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a calcium-based thermochemical energy storage system and method coupled with a flue gas direct carbon capture system to solve the technical problems that the equipment structure is complex and it is difficult to balance the calcination reaction heat and carbonation reaction heat of the material when applying the CaO / CaCO3 thermochemical energy storage system to the field of flue gas direct carbon capture in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: The present invention provides a calcium-based thermochemical energy storage system coupled with a flue gas direct carbon capture system, including a flue gas calcination reaction system, a carbon dioxide collection system, and a flue gas direct carbon capture system; The material inlet of the flue gas calcination reaction system is connected to the material outlet of the flue gas direct carbon capture system, the material outlet of the flue gas calcination reaction system is connected to the material inlet of the flue gas direct carbon capture system, and the inlet of the carbon dioxide collection system is connected to the exhaust gas of the flue gas calcination reaction system; The flue gas calcination reaction system is used to calcine calcium carbonate with high-temperature flue gas to decompose it into calcium oxide and carbon dioxide, realizing heat storage; The carbon dioxide collection system is used to collect and store the carbon dioxide discharged by the flue gas calcination reaction system; The flue gas direct carbon capture system is used to carry out a carbonation reaction between the desulfurized flue gas and the calcium oxide generated in the flue gas calcination reaction system to generate calcium carbonate and release heat.

[0006] Furthermore, the flue gas calcination reaction system includes a flue gas calcination reactor, a calcium oxide storage tank, and a calcium carbonate conveying pipeline; The top end of the side wall of the flue gas calcination reactor is provided with a high-temperature flue gas outlet, and the bottom end of the side wall of the flue gas calcination reactor is provided with a high-temperature flue gas inlet; the bottom material outlet of the flue gas calcination reactor is connected to the inlet of the calcium oxide storage tank, and the outlet of the calcium oxide storage tank is connected to the material inlet of the flue gas direct carbon capture system; the top material inlet of the flue gas calcination reactor is connected to the material outlet of the flue gas direct carbon capture system; A number of heat storage unit modules are arranged inside the flue gas calcination reactor, and the number of the heat storage unit modules is vertically and spacedly arranged inside the flue gas calcination reactor; wherein, a calcium carbonate particle channel is arranged inside the heat storage unit module, and the calcium carbonate particle channel is used as a circulation channel and a decomposition reaction chamber for calcium carbonate; the outside of the heat storage unit module is a high-temperature flue gas channel, and the high-temperature flue gas channel is used as a circulation channel for high-temperature flue gas; An exhaust pipe is further arranged inside the heat storage unit module, and the outlet of the exhaust pipe is connected to the inlet of the carbon dioxide collection system.

[0007] Furthermore, the heat storage unit module includes a unit main body, and the unit main body is a hollow cylindrical structure; the inner cavity of the unit main body serves as the calcium carbonate particle channel; A number of guide plates are arranged on both sides of the calcium carbonate particle channel in a staggered manner from top to bottom; Wherein, one end of the guide plate is connected to the inner wall of the unit main body, and the other end of the guide plate extends obliquely downward towards the longitudinal center line of the unit main body; the exhaust pipe is arranged on the inner wall of the unit main body and is located below the guide plate.

[0008] Furthermore, a cooling pipeline is further arranged inside the flue gas calcination reactor; the cooling pipeline is arranged below the heat storage unit module; wherein, the inlet of the cooling pipeline is used to be connected to a process water pipeline, and the outlet of the cooling pipeline is used to be connected to a steam pipeline.

[0009] Furthermore, the carbon dioxide collection system includes a CO2 storage tank, a CO2 vacuum pump, a CO2 cooling heat exchanger, and a feed water pump; The inlet of the CO2 vacuum pump is connected to the outlet of the exhaust pipe. The outlet of the CO2 vacuum pump is connected to the hot-side inlet of the CO2 cooling heat exchanger. The hot-side outlet of the CO2 cooling heat exchanger is connected to the inlet of the CO2 storage tank. The outlet of the feed water pump is connected to the cold-side inlet of the CO2 cooling heat exchanger. The cold-side outlet of the CO2 cooling heat exchanger is connected to the inlet of the cooling pipeline. The inlet of the feed water pump is connected to the process water pipeline.

[0010] Furthermore, the flue gas direct carbon capture system includes a calcium carbonate storage tank and a carbon capture reactor; The top inlet of the carbon capture reactor is connected to the outlet of the calcium oxide storage tank. The bottom outlet of the carbon capture reactor is connected to the inlet of the calcium carbonate storage tank. The outlet of the calcium carbonate storage tank is connected to the top material inlet of the flue gas calcination reactor.

[0011] Furthermore, the flue gas direct carbon capture system further includes a steam heater, a flue gas cooler, and a flue gas preheating reactor; The shell-side inlet of the steam heater is connected to the gas outlet of the carbon capture reactor. The shell-side outlet of the steam heater is connected to the tube-side inlet of the flue gas preheating reactor. The tube-side outlet of the flue gas preheating reactor is connected to the shell-side inlet of the flue gas cooler. The shell-side outlet of the flue gas cooler is used to be connected to the decarbonized clean flue gas pipeline; The tube-side inlet of the steam heater is connected to the outlet of the cooling pipeline. The tube-side outlet of the steam heater is used to be connected to the steam pipeline. The shell-side inlet of the flue gas preheating reactor is used to be connected to the desulfurized clean flue gas duct. The shell-side outlet of the flue gas waste heat reactor is connected to the gas inlet of the carbon capture reactor.

[0012] Furthermore, on both sides of the material bed layer inside the carbon capture reactor, grid plates arranged oppositely are respectively provided; wherein, a plurality of grids are inclinedly arranged in the grid plates.

[0013] Furthermore, both calcium carbonate and calcium oxide are transported by gas; the particle size of calcium carbonate is 3 - 15 mm.

[0014] The present invention also provides a calcium-based thermochemical energy storage method coupling a flue gas direct carbon capture system, using the calcium-based thermochemical energy storage system coupling the flue gas direct carbon capture system; The calcium-based thermochemical energy storage method coupling the flue gas direct carbon capture system includes: Energy storage process: The calcium carbonate generated during the energy release process serves as a thermochemical heat storage material and enters the flue gas calcination reaction system; in the flue gas calcination reaction system, the calcium carbonate tumbles and flows downward under the action of gravity; among them, during the process of the calcium carbonate tumbling and flowing downward, it exchanges heat with the high-temperature flue gas entering the flue gas calcination reaction system and decomposes to generate calcium oxide and carbon dioxide, realizing heat storage; Energy release process: The calcium oxide generated during the energy storage process serves as a thermochemical energy storage material and enters the flue gas direct carbon capture system; in the flue gas direct carbon capture system, the calcium oxide falls under the action of gravity; among them, during the process of the calcium oxide falling, it undergoes a carbonation reaction with the desulfurized flue gas entering the flue gas direct carbon capture system to generate calcium carbonate, realizing heat release.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The calcium-based thermochemical energy storage system coupled with the flue gas direct carbon capture system provided by the present invention performs the calcination decomposition of calcium carbonate in the flue gas calcination reaction system to complete the heat storage process, and performs the carbonation reaction of calcium oxide in the flue gas direct carbon capture system to complete the heat release process, realizing the separate and independent progress of the heat storage and release processes, which is convenient for the heat balance of the calcination reaction heat and the carbonation reaction heat; among them, the heat storage capacity and the carbon capture capacity are determined by the capacity of the material storage tank, and the system design is simple and highly flexible; the carbon capture technology is coupled during the energy storage process, which can achieve low-cost or even near-zero energy consumption carbon capture, and has significant cost advantages.

[0016] Furthermore, the materials are in a moving and mixing state in the calcination reactor and the carbon capture reactor, effectively preventing problems such as material caking and agglomeration, and improving the cycle life of the materials.

[0017] Furthermore, the high-temperature flue gas channels and the material channels in the calcination reactor are arranged at intervals for indirect heat exchange, solving the problem of heat exchange of dusty flue gas. At the same time, the design of the thin-layer material channel and the indirect heat exchange with the large flat plate effectively solve the problem of relatively poor thermal conductivity of solid-phase particles (calcium-based oxygen carriers); Furthermore, the system adopts a heat cascade utilization waste heat recovery method, with high heat utilization rate and high overall thermal efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a structural block diagram of the calcium-based thermochemical energy storage system coupled with the flue gas direct carbon capture system provided for the embodiment; Figure 2 It is the top view of the flue gas calcination reactor in the embodiment; Figure 3 It is the sectional view of the heat storage unit module in the embodiment; Figure 4 It is the structural schematic diagram of the carbon capture reactor in the embodiment; Figure 5 It is the attached Figure 4 Partial enlarged schematic diagram at position A in the figure.

[0020] Among them, 100, flue gas calcination reaction system; 200, CO2 collection system; 300, flue gas direct carbon capture system; 1, flue gas calcination reactor; 2, high-temperature flue gas outlet; 3, high-temperature flue gas inlet; 4, CO2 storage tank; 5, CO2 vacuum pump; 6, CO2 cooling heat exchanger; 7, feed water pump; 8, process water pipeline; 9, cooling pipeline; 10, calcium oxide storage tank; 11, calcium oxide conveying pipeline; 12, calcium carbonate conveying pipeline; 13, calcium carbonate storage tank; 14, steam heater; 15, flue gas cooler; 16, steam pipeline; 17, carbon capture reactor; 18, flue gas preheating reactor; 19, desulfurized clean flue gas duct; 20, cooling water pipe; 21, economizer pipeline; 22, decarbonized clean flue gas pipeline; 23, heat storage unit module; 101, calcium carbonate particle channel; 102, high-temperature flue gas channel; 103, exhaust pipe; 201, guide plate; 301, grille plate; 302, grille. Specific embodiments

[0021] In order to make the technical problems, technical solutions and beneficial effects solved by the present application clearer and more understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application; obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0022] The present invention provides a calcium-based thermochemical energy storage system coupled with a flue gas direct carbon capture system, including a flue gas calcination reaction system 100, a carbon dioxide collection system 200, and a flue gas direct carbon capture system 300; the material inlet of the flue gas calcination reaction system 100 is connected to the material outlet of the flue gas direct carbon capture system 300, the material outlet of the flue gas calcination reaction system 100 is connected to the material inlet of the flue gas direct carbon capture system 300, and the inlet of the carbon dioxide collection system 200 is connected to the exhaust gas of the flue gas calcination reaction system 100; the flue gas calcination reaction system 100 is used to calcine calcium carbonate with high-temperature flue gas to decompose it into calcium oxide and carbon dioxide, realizing heat storage; the carbon dioxide collection system 200 is used to collect and store the carbon dioxide discharged from the flue gas calcination reaction system 100; the flue gas direct carbon capture system 300 is used to carry out a carbonation reaction between the desulfurized flue gas and the calcium oxide generated in the flue gas calcination reaction system 100 to generate calcium carbonate, realizing heat release.

[0023] In the calcium-based thermochemical energy storage system coupled with the flue gas direct carbon capture system of the present invention, the calcination and decomposition of calcium carbonate are carried out in the flue gas calcination reaction system to complete the heat storage process, and the carbonation reaction of calcium oxide is carried out in the flue gas direct carbon capture system to complete the heat release process, realizing the separate and independent progress of the heat storage and release processes, which is convenient for the heat balance of the calcination reaction heat and the carbonation reaction heat; in the present invention, coupling the carbon capture technology during the energy storage process can achieve low-cost or even near-zero energy consumption carbon capture, with significant cost advantages, simple system design and high flexibility.

[0024] Embodiment As shown in the Figures 1-5 accompanying drawings, the present embodiment provides a calcium-based thermochemical energy storage system coupled with a flue gas direct carbon capture system, including a flue gas calcination reactor system 100, a CO2 collection system 200, and a flue gas direct carbon capture system 300.

[0025] In the present embodiment, the shown flue gas calcination reaction system 100 includes a flue gas calcination reactor 1, a calcium oxide storage tank 10, and a calcium carbonate conveying pipeline 12; a high-temperature flue gas outlet 2 is provided at the top end of the side wall of the flue gas calcination reactor 1, and a high-temperature flue gas inlet 3 is provided at the bottom end of the side wall of the flue gas calcination reactor 1; a top material inlet is provided at the top of the flue gas calcination reactor 1, and a bottom material outlet is provided at the bottom of the flue gas calcination reactor 1.

[0026] The bottom material outlet of the flue gas calcination reactor 1 is connected to the inlet of the calcium oxide storage tank 10, the outlet of the calcium oxide storage tank 10 is connected to the material inlet of the flue gas direct carbon capture system 300, and the top material inlet of the flue gas calcination reactor 1 is connected to the material outlet of the flue gas direct carbon capture system 300; specifically, the outlet of the calcium oxide storage tank 10 is connected to the inlet of the calcium oxide conveying pipeline 11 in the flue gas direct carbon capture system 300; the top material inlet of the flue gas calcination reactor 1 is connected to the outlet of the calcium carbonate conveying pipeline 12, and the inlet of the calcium carbonate conveying pipeline 12 is connected to the outlet of the calcium carbonate storage tank 13 in the flue gas direct carbon capture system 300.

[0027] It should be noted that the calcium oxide conveying pipeline 11 is used to convey calcium oxide in the calcium oxide storage tank 10 to the top inlet of the carbon capture reactor 17 in the flue gas direct carbon capture system 300 by means of gas transportation; the calcium carbonate conveying pipeline 12 is used to convey calcium carbonate in the calcium carbonate storage tank 13 to the top material inlet of the flue gas calcination reactor 1 by means of gas transportation; preferably, the particle size of calcium carbonate is 3-15 mm.

[0028] A number of heat storage unit modules 23 and cooling pipelines 9 are arranged inside the flue gas calcination reactor 1, and a number of the heat storage unit modules 23 are arranged vertically at intervals inside the flue gas calcination reactor 1; wherein, a calcium carbonate particle channel 101 is arranged inside the heat storage unit module 23, and the calcium carbonate particle channel 101 is used as a circulation channel and a decomposition reaction chamber for calcium carbonate; the outside of the heat storage unit module 23 is a high-temperature flue gas channel 102, and the high-temperature flue gas channel 102 is used as a circulation channel for high-temperature flue gas; specifically, a high-temperature flue gas channel 102 is formed between adjacent heat storage unit modules 23 and between the heat storage unit 23 and the inner wall of the flue gas calcination reactor 1.

[0029] The heat storage unit module 23 includes a unit main body, a number of guide plates 201 and an exhaust pipe 103; the unit main body is a hollow cylindrical structure, a material inlet is arranged at the top of the unit main body, a material outlet is arranged at the bottom of the unit main body, and the inner cavity of the unit main body serves as the calcium carbonate particle channel 101; that is, a material channel is arranged vertically inside the unit main body to serve as the calcium carbonate particle channel 101.

[0030] On both sides of the calcium carbonate particle channel 101, a number of material guiding plates 201 are staggeredly arranged from top to bottom; specifically, a number of material guiding plates 201 are inclined and arranged on the inner walls of both sides of the unit main body, and are staggeredly arranged on both sides of the calcium carbonate particle channel 101 from top to bottom in sequence; wherein, one end of the material guiding plate 201 is connected to the inner wall of the unit main body, and the other end of the material guiding plate 201 extends obliquely downward towards the longitudinal center line of the unit main body; preferably, the included angle between the material guiding plate 201 and the horizontal direction is 50°-75°.

[0031] The exhaust pipe 103 is arranged inside the heat storage unit module 23, and the outlet of the exhaust pipe 103 is connected to the inlet of the carbon dioxide collection system 200; wherein, the exhaust pipe 103 is used as a steam outlet channel; specifically, the exhaust pipe 103 is arranged on the inner wall of the unit main body and is located below the material guiding plate 201.

[0032] The cooling pipeline 9 is arranged below the heat storage unit module 23; wherein, the inlet of the cooling pipeline 9 is used to be connected to the process water pipeline 8, and the outlet of the cooling pipeline 9 is used to be connected to the steam pipeline 16.

[0033] In this embodiment, the CO2 collection system 200 includes a CO2 storage tank 4, a CO2 vacuum pump 5, a CO2 cooling heat exchanger 6 and a feed water pump 7; the inlet of the CO2 vacuum pump 5 is connected to the outlet of the exhaust pipe 103, the outlet of the CO2 vacuum pump 5 is connected to the hot side inlet of the CO2 cooling heat exchanger 6, and the hot side outlet of the CO2 cooling heat exchanger 6 is connected to the inlet of the CO2 storage tank 4; the cold side inlet of the CO2 cooling heat exchanger 6 is connected to the outlet of the feed water pump 7, the cold side outlet of the CO2 cooling heat exchanger 6 is connected to the inlet of the cooling pipeline 9, and the inlet of the feed water pump 7 is connected to the process water pipeline 8.

[0034] In this embodiment, the flue gas direct carbon capture system 300 includes a calcium oxide conveying pipeline 11, a calcium carbonate storage tank 13, an evaporation reactor 14, a flue gas cooling reactor 15, a carbon capture reactor 17 and a flue gas preheating reactor 18.

[0035] The top of the carbon capture reactor 17 is provided with a top inlet, the bottom of the carbon capture reactor 17 is provided with a bottom inlet, a gas inlet is provided on one side wall of the carbon capture reactor 17, and a gas outlet is provided on the other side wall of the carbon capture reactor 17; a material bed layer is arranged inside the carbon capture reactor 17, and oppositely arranged grid plates 301 are respectively arranged on both sides of the material bed layer inside the carbon capture reactor 17; wherein, a plurality of grids 302 are inclined in the grid plate 301; preferably, the included angle a between the grid 302 and the horizontal plane is 40°-70°, and the bed layer thickness of the material bed layer inside the carbon capture reactor 17 is 1.5-3 m.

[0036] The inlet of the calcium oxide conveying pipeline 11 is connected to the outlet of the calcium oxide storage tank 10, and the outlet of the calcium oxide conveying pipeline 11 is connected to the top inlet of the carbon capture reactor 17; the bottom outlet of the carbon capture reactor 17 is connected to the inlet of the calcium carbonate storage tank 13, and the outlet of the calcium carbonate storage tank 13 is connected to the top material inlet of the flue gas calcination reactor 1; specifically, the outlet of the calcium carbonate storage tank 13 is connected to the inlet of the calcium carbonate conveying pipeline 12, and the outlet of the calcium carbonate conveying pipeline 12 is connected to the top material inlet of the flue gas calcination reactor 1.

[0037] The shell side inlet of the steam heater 14 is connected to the gas outlet of the carbon capture reactor 17, the shell side outlet of the steam heater 14 is connected to the tube side inlet of the flue gas preheating reactor 18, the tube side outlet of the flue gas preheating reactor 18 is connected to the shell side inlet of the flue gas cooler 15, and the shell side outlet of the flue gas cooler 15 is connected to the decarbonized clean flue gas pipeline 22.

[0038] The tube side inlet of the steam heater 14 is connected to the outlet of the cooling pipeline 9, and the tube side outlet of the steam heater 14 is connected to the steam pipeline 16; the shell side inlet of the flue gas preheating reactor 18 is connected to the desulfurized clean flue gas duct 19, and the shell side outlet of the flue gas waste heat reactor 18 is connected to the gas inlet of the carbon capture reactor 17; the tube side inlet of the flue gas cooler 15 is connected to the cooling water pipe 20, and the tube side outlet of the flue gas cooler 15 is connected to the economizer pipeline 21.

[0039] Energy storage principle and operation method: When the calcium-based thermochemical energy storage system of the coupled flue gas direct carbon capture system of the present invention operates, it is as follows: (1) Energy storage process: The calcium carbonate generated during the energy release process enters the flue gas calcination reaction system 100 as a thermochemical energy storage material. In the flue gas calcination reaction system 100, the calcium carbonate tumbles and flows downward under the action of gravity. Among them, during the process of the calcium carbonate tumbling and flowing downward, it exchanges heat with the high-temperature flue gas entering the flue gas calcination reaction system 100 and decomposes into calcium oxide and carbon dioxide, realizing heat storage.

[0040] Specifically, the energy storage process includes: The calcium carbonate is added from the top material inlet of the flue gas calcination reactor 1, tumbles and flows downward between the staggered guide plates 201 under the action of gravity, passes through the calcination reaction zone and the cooling zone of the flue gas calcination reactor 1 in sequence, and then enters the calcium oxide storage tank 10. Among them, the calcination reaction zone of the flue gas calcination reactor 1 is the area where the energy storage unit module is located, and the cooling zone of the flue gas calcination reactor 1 is the area where the cooling pipeline 9 is located. The high-temperature flue gas enters from the high-temperature flue gas inlet of the flue gas calcination reactor 1, exchanges heat indirectly with the calcium carbonate in the energy storage unit module 23, and then is discharged from the high-temperature flue gas outlet. When the high-temperature flue gas exchanges heat with the calcium carbonate, the CO2 gas generated by the high-temperature decomposition of the calcium carbonate is pumped out by the CO2 vacuum pump 5 through the exhaust pipe 103, cooled by the CO2 cooling heat exchanger 6, and then enters the CO2 storage tank 4. The feed water pump 7 sends the process water in the process water pipeline 8 into the CO2 cooling heat exchanger 6 and the cooling pipeline 9 in sequence to evaporate and heat up, and then is heated by the steam heater 14 and sent into the steam pipeline 16.

[0041] (2) Energy release process: The calcium oxide generated during the energy storage process enters the flue gas direct carbon capture system 300 as a thermochemical energy storage material. In the flue gas direct carbon capture system 300, the calcium oxide falls under the action of gravity. Among them, during the process of the calcium oxide falling, it undergoes a carbonation reaction with the desulfurized flue gas entering the flue gas direct carbon capture system 300 to generate calcium carbonate, realizing heat release.

[0042] Specifically, the energy release process includes: The calcium oxide is transported from the calcium oxide storage tank 10 to the top inlet of the carbon capture reactor 17 through the calcium oxide transport pipeline 11 and falls in the carbon capture reactor 17 under the action of gravity. When the calcium oxide directly contacts the desulfurized flue gas and undergoes a decarbonization reaction to form calcium carbonate, it enters the calcium carbonate storage tank 13. Among them, the desulfurized flue gas is first heated by the flue gas preheater 18, and then enters the carbon capture reactor 17 for carbonation reaction to form decarbonized clean flue gas. After the thermochemical reaction releases heat, the decarbonized clean flue gas is heated up, and then the decarbonized clean flue gas passes through the steam heater 14, the flue gas preheater 18, and the flue gas cooler 15 in sequence for cooling and then is discharged.

[0043] In this embodiment, the temperature of the flue gas calcination reactor 1 is controlled at 750 - 900 °C; the bed temperature of the carbon capture reactor 17 is controlled at 600 - 750 °C; the temperature of the decarbonized clean flue gas at the outlet of the flue gas cooler 15 is lower than 55 °C; the flue gas after desulfurization is first heated by the flue gas preheater 18 and controlled at 300 - 450 °C.

[0044] In the calcium-based thermochemical energy storage system of the coupled flue gas direct carbon capture system described in this embodiment, a high-temperature flue gas inlet 3 is provided at the bottom of the side wall of the flue gas calcination reactor 1, a high-temperature flue gas outlet 2 is provided at the top of the side wall of the flue gas calcination reactor 1, the bottom material outlet of the flue gas calcination reactor 1 is connected to the inlet of the calcium oxide storage tank 10, and the outlet of the calcium oxide storage tank 10 is connected to the top inlet of the carbon capture reactor 17; a heat storage unit module 23 is arranged inside the flue gas calcination reactor 1. Inside the heat storage unit module 23 is a calcium carbonate particle channel 101, and outside is a high-temperature flue gas channel 102; a cooling pipeline 9 is arranged at the lower part of the heat storage unit module 23; the bottom outlet of the carbon capture reactor 17 is connected to the calcium carbonate storage tank 13, and the calcium carbonate storage tank 13 is connected to the top inlet of the flue gas calcination reactor 1; the desulfurized clean flue gas duct 19 is sequentially connected to the low-temperature side of the flue gas preheater 18, the flue gas inlet of the carbon capture reactor 17, the shell side of the steam heater 14, the high-temperature side of the flue gas preheater 18, the flue gas cooler 15, and the decarbonized clean flue gas pipeline 22; the exhaust pipe 103 of the heat storage unit module 23 is sequentially connected to the CO2 vacuum pump 5, the CO2 cooling heat exchanger 6, and the CO2 storage tank 4; the process water pipeline 8 is sequentially connected to the feed water pump 7, the CO2 cooling heat exchanger 6, the cooling pipeline 9, the steam heater 14, and the steam pipeline 16; the tube side inlet of the flue gas cooler 15 is connected to the cooling water pipe 20, and the tube side outlet is connected to the economizer pipeline 21; in this embodiment, CaO / CaCO3 is used as the thermochemical reaction material, and the heat storage and heat release processes are respectively realized by the independently arranged flue gas calcination reactor 1 and carbon capture reactor 17, that is, (1) the heat storage process of calcium carbonate calcination and the heat release process of calcium oxide carbonation reaction are respectively carried out in the flue gas calcination reactor 1 and the carbon capture reactor 17, so that the storage and release processes are carried out separately, and the heat storage capacity and carbon capture capacity are determined by the capacity of the material storage tank. The system design is simple and has high flexibility.

[0045] In the present invention, by coupling the carbon capture technology during the energy storage process, low-cost or even near-zero energy consumption carbon capture can be achieved, and the cost advantage is significant; among them, the materials can be in a moving and mixing state in both the flue gas calcination reactor and the carbon capture reactor, effectively preventing problems such as material caking and agglomeration, and improving the cycle life of the materials; secondly, the high-temperature flue gas channel and the calcium carbonate particle channel in the flue gas calcination reactor are arranged at intervals and indirectly exchange heat, solving the problem of heat exchange of dusty flue gas. At the same time, the thin-layer material channel design and the large flat plate indirect heat exchange effectively solve the problem of poor thermal conductivity of solid-phase particles; in addition, the system adopts a heat cascade utilization waste heat recovery method, with high heat utilization rate and high system comprehensive thermal efficiency.

[0046] The above embodiments are merely one of the implementation manners capable of implementing the technical solution of the present invention. The scope of protection required by the present invention is not limited solely by this embodiment, but also includes variations, substitutions, and other implementation manners that are readily conceivable to any person skilled in the art within the technical scope disclosed by the present invention.

Claims

1. A calcium-based thermochemical energy storage system coupled with a flue gas direct carbon capture system, characterized in that, It includes a flue gas calcination reaction system (100), a carbon dioxide collection system (200) and a flue gas direct carbon capture system (300); The material inlet of the flue gas calcination reaction system (100) is connected to the material outlet of the flue gas direct carbon capture system (300), the material outlet of the flue gas calcination reaction system (100) is connected to the material inlet of the flue gas direct carbon capture system (300), and the inlet of the carbon dioxide collection system (200) is connected to the exhaust gas of the flue gas calcination reaction system (100); The flue gas calcination reaction system (100) is used to calcine calcium carbonate with high-temperature flue gas to decompose it into calcium oxide and carbon dioxide, so as to realize heat storage; The carbon dioxide collection system (200) is used to collect and store the carbon dioxide discharged by the flue gas calcination reaction system (100); The flue gas direct carbon capture system (300) is used to carry out a carbonation reaction between the desulfurized flue gas and the calcium oxide generated in the flue gas calcination reaction system (100) to generate calcium carbonate, so as to realize heat release.

2. The calcium-based thermochemical energy storage system of a coupled flue gas direct carbon capture system according to claim 1, wherein, The flue gas calcination reaction system (100) includes a flue gas calcination reactor (1), a calcium oxide storage tank (10) and a calcium carbonate conveying pipeline (12); A high-temperature flue gas outlet (2) is arranged at the top end of the side wall of the flue gas calcination reactor (1), and a high-temperature flue gas inlet (3) is arranged at the bottom end of the side wall of the flue gas calcination reactor (1); the material outlet at the bottom end of the flue gas calcination reactor (1) is connected to the inlet of the calcium oxide storage tank (10), and the outlet of the calcium oxide storage tank (10) is connected to the material inlet of the flue gas direct carbon capture system (300); the material inlet at the top end of the flue gas calcination reactor (1) is connected to the material outlet of the flue gas direct carbon capture system (300); A number of heat storage unit modules (23) are arranged inside the flue gas calcination reactor (1), and the number of the heat storage unit modules (23) are vertically arranged at intervals inside the flue gas calcination reactor (1); wherein, a calcium carbonate particle channel (101) is arranged inside the heat storage unit module (23), and the calcium carbonate particle channel (101) is used as a circulation channel and a decomposition reaction chamber for calcium carbonate; the outside of the heat storage unit module (23) is a high-temperature flue gas channel (102), and the high-temperature flue gas channel (102) is used as a circulation channel for high-temperature flue gas; An exhaust pipe (103) is also arranged inside the heat storage unit module (23), and the outlet of the exhaust pipe (103) is connected to the inlet of the carbon dioxide collection system (200).

3. The calcium-based thermochemical energy storage system of a coupled flue gas direct carbon capture system according to claim 2, characterized in that, The heat storage unit module (23) includes a unit main body, and the unit main body is a hollow cylindrical structure; the inner cavity of the unit main body serves as the calcium carbonate particle channel (101); A number of guide plates (201) are arranged on both sides of the calcium carbonate particle channel (101) in a staggered manner from top to bottom; One end of the material guiding plate (201) is connected to the inner wall of the unit body, and the other end of the material guiding plate (201) extends obliquely downward towards the longitudinal center line of the unit body; the exhaust pipe (103) is arranged on the inner wall of the unit body and is placed below the material guiding plate (201).

4. The calcium-based thermochemical energy storage system of a coupled flue gas direct carbon capture system according to claim 2, wherein A cooling pipeline (9) is further arranged inside the flue gas calcination reactor (1); the cooling pipeline (9) is arranged below the heat storage unit module (23); wherein, the inlet of the cooling pipeline (9) is used to be connected to a process water pipeline (8), and the outlet of the cooling pipeline (9) is used to be connected to a steam pipeline (16).

5. The calcium-based thermochemical energy storage system of a coupled flue gas direct carbon capture system according to claim 4, characterized in that, The carbon dioxide collection system (200) includes a CO2 storage tank (4), a CO2 vacuum pump (5), a CO2 cooling heat exchanger (6) and a feed water pump (7); The inlet of the CO2 vacuum pump (5) is connected to the outlet of the exhaust pipe (103), the outlet of the CO2 vacuum pump (5) is connected to the hot side inlet of the CO2 cooling heat exchanger (6), and the hot side outlet of the CO2 cooling heat exchanger (6) is connected to the inlet of the CO2 storage tank (4); the outlet of the feed water pump (7) is connected to the cold side inlet of the CO2 cooling heat exchanger (6), the cold side outlet of the CO2 cooling heat exchanger (6) is connected to the inlet of the cooling pipeline (9), and the inlet of the feed water pump (7) is connected to the process water pipeline (8).

6. The calcium-based thermochemical energy storage system of a coupled flue gas direct carbon capture system according to claim 4, characterized in that, The flue gas direct carbon capture system (300) includes a calcium carbonate storage tank (13) and a carbon capture reactor (17); The top inlet of the carbon capture reactor (17) is connected to the outlet of the calcium oxide storage tank (10), the bottom outlet of the carbon capture reactor (17) is connected to the inlet of the calcium carbonate storage tank (13), and the outlet of the calcium carbonate storage tank (13) is connected to the top material inlet of the flue gas calcination reactor (1).

7. The calcium-based thermochemical energy storage system of a coupled flue gas direct carbon capture system according to claim 6, characterized in that, The flue gas direct carbon capture system (300) further includes a steam heater (14), a flue gas cooler (15) and a flue gas preheating reactor (18); The shell side inlet of the steam heater (14) is connected to the gas outlet of the carbon capture reactor (17), the shell side outlet of the steam heater (14) is connected to the tube side inlet of the flue gas preheating reactor (18), the tube side outlet of the flue gas preheating reactor (18) is connected to the shell side inlet of the flue gas cooler (15), and the shell side outlet of the flue gas cooler (15) is used to be connected to a decarbonized clean flue gas pipeline (22); The tube side inlet of the steam heater (14) is connected to the outlet of the cooling pipeline (9), and the tube side outlet of the steam heater (14) is used to be connected to the steam pipeline (16); the shell side inlet of the flue gas preheating reactor (18) is used to be connected to a desulfurized clean flue gas duct (19), and the shell side outlet of the flue gas waste heat reactor (18) is connected to the gas inlet of the carbon capture reactor (17).

8. The calcium-based thermochemical energy storage system of a coupled flue gas direct carbon capture system according to claim 6, wherein, On both sides of the material bed layer inside the carbon capture reactor (17), grid plates (301) arranged oppositely are respectively provided; wherein, a plurality of grids (302) are obliquely arranged in the grid plates (301).

9. The calcium-based thermochemical energy storage system of a coupled flue gas direct carbon capture system according to claim 1, characterized in that, Both calcium carbonate and calcium oxide are transported by gas; the particle size of calcium carbonate is 3 - 15 mm.

10. A calcium-based thermochemical energy storage method for a coupled flue gas direct carbon capture system, characterized in that, A calcium-based thermochemical energy storage system using the coupled flue gas direct carbon capture system according to any one of claims 1 - 9; The calcium-based thermochemical energy storage method of the coupled flue gas direct carbon capture system includes: Energy storage process: The calcium carbonate generated during the energy release process is used as a thermochemical heat storage material and enters the flue gas calcination reaction system (100); in the flue gas calcination reaction system (100), the calcium carbonate tumbles and flows down by gravity; wherein, during the process of the calcium carbonate tumbling and flowing down, it exchanges heat with the high-temperature flue gas entering the flue gas calcination reaction system (100) and decomposes to generate calcium oxide and carbon dioxide, realizing heat storage; Energy release process: The calcium oxide generated during the energy storage process is used as a thermochemical energy storage material and enters the flue gas direct carbon capture system (300); in the flue gas direct carbon capture system (300), the calcium oxide falls by gravity; wherein, during the process of the calcium oxide falling, it undergoes a carbonation reaction with the desulfurized flue gas entering the flue gas direct carbon capture system (300) to generate calcium carbonate, realizing heat release.

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