A carbon dioxide in-situ enrichment system and process

Abstract

The present invention relates to the technical field of carbon dioxide capture, and in particular to a carbon dioxide in-situ enrichment system and process. The system includes a decomposition furnace, a coal powder feeding device, a separation device, and a cooling recovery device, wherein: a gas injection port is provided at the lower end of the decomposition furnace, and a coal powder injection port and a raw material injection port are provided on the side wall of the decomposition furnace; the outlet of the coal powder feeding device is connected to the coal powder injection port through a pipeline; the separation device is used for gas-solid separation; the cooling recovery device is used for cooling carbon dioxide flue gas; the decomposition furnace, the separation device, and the cooling recovery device are connected in sequence through pipelines, and the outlet of the cooling recovery device is connected to the gas injection port and the coal powder feeding device through pipelines respectively. The system uses high-concentration carbon dioxide gas discharged from the cooling recovery device as coal powder conveying gas and combustion-supporting gas, which can reduce the amount of air entering the system, increase the carbon dioxide enrichment concentration in the system, and realize in-situ enrichment of carbon dioxide gas.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and in particular to a carbon dioxide in-situ enrichment system and process. Background Art

[0002] The cement industry is one of the main carbon dioxide emission industries in my country, and the carbon dioxide produced by cement production accounts for 7% of the total global carbon dioxide emissions. The traditional cement industry carbon capture mainly adopts chemical absorption process and external combustion high temperature calcination rotary kiln decarbonization process. Among them: the chemical absorption process uses amine solution to absorb and desorb to obtain high concentration carbon dioxide. The advantage of this process is that the equipment has been maturely applied in the chemical industry, and the disadvantage is that the power consumption is large and the system consumption is high; the principle of the external combustion high temperature calcination rotary kiln carbon capture process is to separate a certain amount of raw materials originally sent to the preheater discharge pipe according to the requirements of the amount of captured carbon dioxide and send it to the external combustion high temperature calcination rotary kiln for decomposition. The advantage of this process is that the principle is simple, the investment cost and operation cost are relatively low, and its disadvantage is that the high temperature resistance of the kiln shell material is very high.

[0003] In view of the defects of the traditional carbon capture process, the pure oxygen combustion process has begun to be used in this field to capture cement carbon. The principle of the pure oxygen combustion process is to use high-purity oxygen as fuel to replace traditional air. In the process of carbon capture using the pure oxygen combustion process, the coal powder needs to be sent into the decomposition furnace under the action of the air flow. The air entering the decomposition furnace will affect the concentration of oxygen and carbon dioxide in the furnace, which may lead to incomplete combustion and incomplete decomposition, and will also affect the subsequent capture and purification of carbon dioxide. Summary of the invention

[0004] The first purpose of the present invention is to provide a carbon dioxide in-situ enrichment system to solve the technical problem in the prior art that the air entering the decomposition furnace along with the coal powder will affect the concentration of oxygen and carbon dioxide in the furnace, which may lead to incomplete combustion and incomplete decomposition.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A carbon dioxide in-situ enrichment system comprises a decomposition furnace, a pulverized coal feeding device, a separation device and a cooling recovery device, wherein: a fuel gas injection port is provided at the lower end of the decomposition furnace, a pulverized coal injection port and a raw meal injection port are provided on the side wall of the decomposition furnace; the pulverized coal feeding device is used to store pulverized coal, and its outlet is connected to the pulverized coal injection port through a pipeline; the separation device is used to perform gas-solid separation on flue gas rich in carbon dioxide; the cooling recovery device is used to cool the carbon dioxide flue gas;

[0007] The decomposition furnace, the separation device and the cooling recovery device are connected in sequence through pipelines, and the outlet of the cooling recovery device is respectively connected to the fuel gas injection port and the pulverized coal feeding device through pipelines.

[0008] Furthermore, the cooling recovery device includes a waste heat boiler, a bag dust collector, a spray cooling system and a main exhaust fan which are sequentially connected through pipelines, and the inlet of the waste heat boiler is connected to the outlet of the separation device through a pipeline.

[0009] Furthermore, an ash hopper is provided at the bottom of the waste heat boiler, and at least two material level meters are provided on the ash hopper;

[0010] An ash discharge pipe is arranged at the bottom of the ash hopper, a star-shaped discharger is arranged on the ash discharge pipe, and the star-shaped discharger is interlockedly controlled with the material level meter.

[0011] Furthermore, it also includes a blowing device, which includes one or more acetylene explosion-burning blowers installed on the side wall of the waste heat boiler;

[0012] When there are multiple acetylene explosion injectors, the multiple acetylene explosion injectors are distributed at intervals along the circumferential direction and / or axial direction of the waste heat boiler.

[0013] Furthermore, it also includes a cleaning pipeline, the inlet of which is connected to the outlet of the cooling recovery device or the outlet of the carbon dioxide liquefaction and purification system, and the outlet of which is connected to the decomposition furnace and the separation device.

[0014] Furthermore, the separation device includes a primary separator, a secondary separator and an air-locking dust collector. The discharge port at the bottom of the primary separator and the discharge port at the bottom of the secondary separator are connected to the inlet of the air-locking dust collector through pipelines, and the outlet of the air-locking dust collector is connected to the cement kiln decomposition furnace through a pipeline.

[0015] Furthermore, it also includes an air-fuel device, which includes an air-fuel shell in a volute structure, an air-fuel chamber formed inside the air-fuel shell, the outlet of the air-fuel chamber is connected to the gas injection port, and a pure oxygen inlet and a circulating gas inlet are provided on the air-fuel chamber, the pure oxygen inlet is used to input oxygen, and the circulating gas inlet is connected to the outlet of the cooling recovery device through a pipeline.

[0016] Furthermore, the air-fuel device further comprises a main burner and a circulating air distributor, wherein:

[0017] The main burner is arranged on the end surface where the circulating gas inlet is located, and the outlet end of the main burner extends into the air combustion chamber;

[0018] The circulating air distributor is mounted on the main burner, and the inlet of the circulating air distributor is connected to the outlet of the cooling recovery device through a pipeline. The circulating air distributor is provided with a plurality of outlets distributed at intervals along the circumferential direction. The number of the circulating air inlets is multiple and corresponds one-to-one with the outlets of the circulating air distributor.

[0019] A second object of the present invention is to provide a process for in-situ enrichment of carbon dioxide, the process comprising the following steps:

[0020] The circulating gas from the cooling recovery device is divided into multiple branches, one of which is mixed with the oxygen from the pure oxygen preparation system and then enters the decomposition furnace through the fuel gas injection port, and another branch enters the pulverized coal conveying device as the conveying gas for the pulverized coal;

[0021] The cold raw materials and hot raw materials are fed into the decomposition furnace in a certain proportion, and the cold and hot raw materials are mixed with the high-temperature airflow generated by the combustion in the decomposition furnace for decomposition.

[0022] Furthermore, the method further comprises the following steps:

[0023] The dusty airflow discharged from the top of the decomposition furnace enters the primary separator, and 30-50% of the raw meal in the dusty airflow is discharged from the discharge port at the bottom of the primary separator and enters the air lock dust collector, and the remaining 50-70% of the raw meal continues to enter the secondary separator with the high-temperature gas;

[0024] 92-95% of the raw meal is discharged from the discharge port at the bottom of the secondary separator and enters the air lock dust collector, and the high-temperature gas discharged from the secondary separator enters the cooling recovery device;

[0025] The cooling recovery device recovers and cools the high-temperature gas and finally outputs carbon dioxide gas with a dry basis concentration of >80%.

[0026] Beneficial effects of the present invention:

[0027] The carbon dioxide in-situ enrichment system provided by the present invention comprises a decomposition furnace, a pulverized coal feeding device, a separation device and a cooling recovery device, wherein: a gas injection port is provided at the lower end of the decomposition furnace, and a pulverized coal injection port and a raw meal injection port are provided on the side wall of the decomposition furnace; the pulverized coal feeding device is used to store pulverized coal, and its outlet is connected to the pulverized coal injection port through a pipeline; the separation device is used to perform gas-solid separation on flue gas rich in carbon dioxide; the cooling recovery device is used to cool the carbon dioxide flue gas; the decomposition furnace, the separation device and the cooling recovery device are connected in sequence through pipelines, and the outlet of the cooling recovery device is respectively connected to the gas injection port and the pulverized coal feeding device through pipelines.

[0028] The carbon dioxide in-situ enrichment system provided in the present application uses high-concentration carbon dioxide gas discharged from the cooling recovery device as the coal powder conveying gas and the combustion-supporting gas entering the decomposition furnace, which can reduce the amount of air entering the system, increase the carbon dioxide enrichment concentration in the system, achieve in-situ enrichment of carbon dioxide gas, and provide good conditions for subsequent capture and purification of carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of a process flow of a carbon dioxide in-situ enrichment system provided in Example 1 of the present invention;

[0031] Figure 2 A schematic diagram of the structure of the wind-locking dust collector provided in the first embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the installation structure of the dust hopper, the level meter and the star-shaped discharger provided in the first embodiment of the present invention;

[0033] Figure 4 A schematic diagram of the installation structure of the waste heat boiler and the injection device provided in the first embodiment of the present invention;

[0034] Figure 5 A schematic diagram of the connection route of the dust cleaning pipeline provided in the first embodiment of the present invention;

[0035] Figure 6 A schematic diagram of a process flow of a carbon dioxide in-situ enrichment system provided in Example 2 of the present invention;

[0036] Figure 7 A schematic diagram of the structure of an air-fuel device provided in Embodiment 2 of the present invention;

[0037] Figure 8 for Figure 7 A schematic cross-sectional view at BB;

[0038] Fig. 9 for Figure 7 A schematic cross-sectional view at AA;

[0039] Fig.10 A schematic diagram of an axial cross section of a main burner provided in Embodiment 2 of the present invention;

[0040] Fig.11 for Figure 7 Schematic cross-sectional view at CC.

[0041] icon:

[0042] 100-calciner; 110-gas injection port;

[0043] 200-coal powder feeding device; 210-coal powder bin; 220-coal powder weighing scale; 230-coal powder batcher;

[0044] 300-separation device; 310-primary separator; 320-secondary separator; 330-wind-locking dust collector;

[0045] 400-Cooling recovery device; 410-Waste heat boiler; 420-Bag dust collector; 430-Spray cooling system; 440-Main exhaust fan; 450-Dust hopper; 460-Level meter; 470-Star discharger;

[0046] 500-injection device; 510-acetylene deflagration injector;

[0047] 600-ash cleaning pipeline; 610-compressed gas storage tank;

[0048] 700-air-combustion device; 710-air-combustion shell; 711-air-combustion chamber; 720-pure oxygen air distributor; 730-main burner; 731-fuel spray gun; 732-coal powder channel; 733-oxygen channel; 734-circulating gas channel; 740-circulating gas air distributor; 750-slag discharge channel; 760-first nozzle; 770-second nozzle;

[0049] 800-electric dispensing valve;

[0050] 900-Cement kiln calciner. DETAILED DESCRIPTION

[0051] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] It should be noted that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0053] It should be noted that in the description of the present invention, the terms "connection" and "installation" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or connected through an intermediate medium; it can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] Embodiment 1

[0055] In the process of carbon capture using pure oxygen combustion technology in the prior art, coal powder needs to be sent into the decomposition furnace under the action of the air flow force. The air entering the decomposition furnace will affect the concentration of oxygen and carbon dioxide in the furnace, which may cause problems such as incomplete combustion and incomplete decomposition, and will also affect the subsequent capture and purification of carbon dioxide.

[0056] Based on this, Example 1 of the present application provides a carbon dioxide in-situ enrichment system, referring to Figure 1 The system comprises a decomposition furnace 100, a pulverized coal feeding device 200, a separation device 300 and a cooling recovery device 400, wherein: a gas injection port 110 is provided at the lower end of the decomposition furnace 100, and a pulverized coal injection port and a raw meal injection port are provided on the side wall of the decomposition furnace 100; the pulverized coal feeding device 200 is used to store pulverized coal, and its outlet is connected to the pulverized coal injection port through a pipeline; the separation device 300 is used to separate the flue gas rich in carbon dioxide from the solid; the cooling recovery device 400 is used to cool the carbon dioxide flue gas;

[0057] The decomposition furnace 100, the separation device 300 and the cooling recovery device 400 are connected in sequence through pipelines, and the outlet of the cooling recovery device 400 is connected to the gas injection port 110 and the pulverized coal feeding device 200 through pipelines.

[0058] The carbonate raw material used in the device provided by the present invention is mainly sourced from cold raw materials entering the cement kiln and hot raw materials from the cement burning system, and the pulverized coal of the cement kiln system is used as the main fuel.

[0059] During the operation of the above system, since the outlet of the cooling recovery device 400 is connected to the gas injection port 110 and the pulverized coal feeding device 200 through pipelines, part of the high-concentration carbon dioxide gas discharged from the cooling recovery device 400 can enter the decomposition furnace 100 and the pulverized coal feeding device 200 for circulation. Part of the high-concentration carbon dioxide gas discharged from the cooling recovery device 400 is mixed with oxygen from the pure oxygen preparation system and enters the circulating fan gas distribution, and the mixed gas enters the decomposition furnace 100 from the gas injection port 110. Part of the high-concentration carbon dioxide gas discharged from the cooling recovery device 400 enters the pulverized coal feeding device 200 and is used as a conveying gas for the pulverized coal to feed the pulverized coal into the decomposition furnace 100.

[0060] As described above, the carbon dioxide in-situ enrichment system provided in the present application uses the high-concentration carbon dioxide gas discharged from the cooling recovery device 400 as the coal powder conveying gas and the combustion-supporting gas entering the decomposition furnace 100, which can reduce the amount of air entering the system, increase the carbon dioxide enrichment concentration in the system, and achieve in-situ enrichment of carbon dioxide gas, providing good conditions for the subsequent capture and purification of carbon dioxide.

[0061] Continue to refer to Figure 1 The pulverized coal feeding device 200 includes a pulverized coal bin 210, a pulverized coal weighing scale 220 and a pulverized coal batcher 230, wherein the pulverized coal bin 210 is used to store pulverized coal; the inlet of the pulverized coal weighing scale 220 is connected to the outlet at the bottom of the pulverized coal bin 210, and the outlet of the pulverized coal weighing scale 220 is connected to the inlet of the pulverized coal batcher 230; the pulverized coal batcher 230 has multiple outlets, and accordingly, the decomposition furnace 100 is provided with multiple pulverized coal injection ports, and the pulverized coal batcher 230 can input pulverized coal into the multiple pulverized coal injection ports.

[0062] Reference Figure 1 and Figure 2 The separation device 300 includes a primary separator 310, a secondary separator 320 and an air-locking dust collector 330. The discharge port at the bottom of the primary separator 310 and the discharge port at the bottom of the secondary separator 320 are connected to the inlet of the air-locking dust collector 330 through a pipeline, and the outlet of the air-locking dust collector 330 is connected to the cement kiln decomposition furnace 900 through a pipeline.

[0063] like Figure 2 As shown, the upper end of the air-locking dust collector 330 is provided with two inlets, and the primary separator 310 and the secondary separator 320 are respectively connected to the two inlets of the air-locking dust collector 330 through pipelines; the lower end of the air-locking dust collector 330 is provided with an outlet, which is connected to the cement kiln decomposition furnace 900 through a pipeline. By adding the air-locking dust collector 330 to the pipeline between the separator and the cement kiln decomposition furnace 900, the air flow interference between the present system and the cement kiln decomposition furnace system can be reduced, the amount of air entering the system can be reduced, and the carbon dioxide enrichment concentration in the system can be further increased.

[0064] Furthermore, the system also includes an electric dosing valve 800, the inlet of the electric dosing valve 800 is used to input hot raw materials, and the electric dosing valve 800 has two outlets, one outlet of the electric dosing valve 800 is connected to the raw material injection port of the decomposition furnace 100 through a pipeline, and the other outlet of the electric dosing valve 800 is connected to the cement kiln decomposition furnace 900 through a pipeline.

[0065] Continue to refer to Figure 1 The cooling recovery device 400 includes a waste heat boiler 410, a bag dust collector 420, a spray cooling system 430 and a main exhaust fan 440 which are sequentially connected through pipelines. The inlet of the waste heat boiler 410 is connected to the outlet of the separation device 300 through a pipeline.

[0066] During the operation of the above system, the dusty high-temperature gas separated by the separation device 300 enters the waste heat boiler 410 for heat recovery and cooling, then enters the bag dust collector 420 for dust removal, then enters the spray cooling system 430 for complete cooling, and finally is discharged under the action of the main exhaust fan 440. Part of the gas discharged from the main exhaust fan 440 enters the carbon dioxide purification and liquefaction system, and the other part is used as circulating gas and is divided into two branches, one of which enters the coal powder feeding device 200 as the conveying gas of the coal powder, and the other circulating gas branch is mixed with oxygen and enters the decomposition furnace 100 as a combustion-supporting gas.

[0067] Reference Figure 3 A dust hopper 450 is provided at the bottom of the waste heat boiler 410 and / or the bottom of the bag dust collector 420, and at least two material level meters 460 are provided on the dust hopper 450;

[0068] An ash discharge pipe is provided at the bottom of the ash hopper 450 , and a star-shaped discharger 470 is provided on the ash discharge pipe. The star-shaped discharger 470 is interlocked with the material level meter 460 for control.

[0069] In this embodiment, an ash hopper 450 is provided at the bottom of the waste heat boiler 410 and the bag dust collector 420, respectively. A level meter 460 is provided at a height of about 1.5 meters on both sides of the ash hopper 450, respectively. The provision of two level meters 460 can prevent one of the level meters 460 from malfunctioning and causing a false alarm, thereby causing the ash hopper to be blocked, thereby affecting the stable operation of the system. When both level meters 460 have level signals, the star-shaped discharger 470 below the ash hopper is started in a chain, and the ash unloading time is adjusted through the program, and stops after 60 seconds to 180 seconds, until the next time both level meters 460 have level signals, the chain unloading is started again. The star-shaped discharger 470 is interlocked with the level meter 460 to reduce air leakage from the waste heat boiler 410 and the bag dust collector 420, thereby reducing the amount of air entering the system and further increasing the carbon dioxide enrichment concentration.

[0070] Reference Figure 4 The carbon dioxide in-situ enrichment system further includes a blowing device 500, and the blowing device 500 includes one or more acetylene explosion-burning blowers 510 installed on the side wall of the waste heat boiler 410;

[0071] When there are multiple acetylene explosion injectors 510 , the multiple acetylene explosion injectors 510 are spaced apart and distributed along the circumferential direction and / or axial direction of the waste heat boiler 410 .

[0072] In this embodiment, there are multiple acetylene deflagration injectors 510, and the multiple acetylene deflagration injectors 510 are arranged in an array along the circumference and axial direction of the waste heat boiler 410 on the side wall of the waste heat boiler 410, so that multiple injection points are formed on the side wall of the waste heat boiler 410. The injection points are evenly arranged in the heat exchange units of each layer of the waste heat boiler 410. The central control can set parameters such as acetylene filling amount, release time, injection interval, injection order, etc. according to needs, so as to effectively clean the waste heat boiler 410.

[0073] Exemplarily, the blowing action of the acetylene deflagration injector 510 can be interlocked with the temperature rise at the outlet of the waste heat boiler 410. For every 10°C increase in the outlet temperature of the waste heat boiler 410, the acetylene deflagration injector 510 performs the blowing action according to the set blowing sequence.

[0074] Compared with the conventional mechanical vibration cleaning method, this embodiment uses the deflagration spraying method for cleaning, which not only has a better cleaning effect, but also does not damage the waste heat boiler 410. In addition, this embodiment uses acetylene as the deflagration gas, and the product of acetylene explosion is mainly carbon dioxide, which can reduce the impact on the carbon dioxide concentration in the system.

[0075] Reference Figure 5 The carbon dioxide in-situ enrichment system also includes a cleaning pipeline 600, the inlet of the cleaning pipeline 600 is connected to the outlet of the cooling recovery device or the outlet of the carbon dioxide liquefaction purification system, and the outlet of the cleaning pipeline 600 is connected to the decomposition furnace 100 and the separation device 300.

[0076] In this embodiment, the dust cleaning pipeline 600 includes a main pipeline and multiple branch pipelines. The inlet of the main pipeline is connected to the outlet of the carbon dioxide liquefaction and purification system to obtain a higher concentration of carbon dioxide; a compressed gas storage tank 610 for storing gas is provided on the main pipeline to prevent insufficient gas blowing force. The primary separator 310 and its discharge pipe are respectively connected to the main pipeline through a branch pipeline, the secondary separator 320 and its discharge pipe are respectively connected to the main pipeline through a branch pipeline, and the decomposition furnace 100, the air-locking dust collector 330 and the bag dust collector 420 are respectively connected to the main pipeline through a branch pipeline. Through the above structure, high-concentration carbon dioxide gas from the carbon dioxide purification and liquefaction system can be used to purge high-temperature equipment such as the decomposition furnace 100, the primary separator 310 and its discharge pipe, the secondary separator 320 and its discharge pipe, etc., to reduce the risk of material accumulation and blockage, and at the same time increase the carbon dioxide concentration in the system.

[0077] In summary, the carbon dioxide in-situ enrichment system provided by the present application uses carbon dioxide gas as the conveying gas for coal powder, the combustion-supporting gas, and the purge gas for high-temperature equipment accumulation, which can reduce the amount of air entering the system and increase the carbon dioxide gas enrichment concentration in the system. In addition, the waste heat boiler 410 is purged by acetylene deflagration injection. Since the product of acetylene deflagration is mainly carbon dioxide gas, the carbon dioxide gas enrichment concentration in the system can be further increased.

[0078] Embodiment 2

[0079] The difference between the carbon dioxide in-situ enrichment system provided in the second embodiment of the present application and the first embodiment is that the carbon dioxide in-situ enrichment system provided in the present embodiment further includes an air-fuel device 700 arranged at the bottom of the decomposition furnace 100 .

[0080] Specifically, refer to Figure 6 and Figure 7 The air-fuel device 700 includes an air-fuel shell 710 with a volute structure, an air-fuel chamber 711 is formed inside the air-fuel shell 710, the outlet of the air-fuel chamber 711 is connected to the gas injection port 110, and a pure oxygen inlet and a circulating gas inlet are provided on the air-fuel chamber 711. The pure oxygen inlet is used to input oxygen, and the circulating gas inlet is connected to the outlet of the cooling recovery device 400 through a pipeline.

[0081] The air-combustion case 710 with a volute structure is adopted. During operation, the combustion and heating airflow in the air-combustion chamber 711 is swirled by the system draft, which prolongs the pulverized coal combustion time and is beneficial to the uniformity of the airflow composition and temperature in the air-combustion chamber 711.

[0082] Reference Figure 7 The air-fuel device 700 further includes a main burner 730 and a circulating air blower 740, wherein:

[0083] The main burner 730 is arranged on the end surface where the circulating gas inlet is located, and the outlet end of the main burner 730 extends into the air combustion chamber 711;

[0084] The circulating air blower 740 is mounted on the main burner 730. The inlet of the circulating air blower 740 is connected to the outlet of the cooling recovery device 400 through a pipeline. The circulating air blower 740 is provided with a plurality of outlets spaced apart along the circumferential direction. The number of the circulating air inlets is multiple and corresponds one-to-one with the outlets of the circulating air blower 740.

[0085] In the above structure, the circulating gas distributor 740 can evenly distribute the circulating gas, so that the circulating gas enters the air combustion chamber 711 in a dispersed manner. The main burner 730 is located at the center of the end face where the circulating gas inlet is located, and the circulating gas distributor 740 is arranged in a ring shape on the periphery of the main burner 730. The circulating gas with a lower temperature in the circulating gas distributor 740 can absorb the local high temperature formed by the combustion of the pulverized coal, thereby protecting the refractory material of the inner wall of the air combustion chamber 711.

[0086] Further, refer to Figure 8 A second nozzle 770 is disposed at each outlet of the circulating air distributor 740. In this embodiment, the circulating air distributor 740 is provided with 6-8 second nozzles 770 arranged in the annular direction, and the second nozzles 770 are inserted into the air-combustion chamber 711 to a depth of 700-300 mm.

[0087] Continue to refer to Figure 7 The air-fuel device 700 also includes a pure oxygen air distributor 720, which is arranged at the bottom of the air-fuel chamber 711. The inlet of the pure oxygen air distributor 720 is used to input oxygen. The pure oxygen air distributor 720 has a plurality of outlets distributed at intervals along the circumference and connected to the air-fuel chamber 711.

[0088] Since the pure oxygen air distributor 720 has a plurality of outlets spaced apart along the circumference, the pure oxygen air distributor 720 can evenly distribute oxygen, so that oxygen can disperse into the air-combustion chamber 711; the oxygen in the air-combustion chamber 711 can disperse into the decomposition furnace 100, so that oxygen can fully contact with raw materials and coal powder, thereby improving the combustion efficiency and the decomposition effect of raw materials. In addition, the pure oxygen air distributor 720 is arranged at the bottom of the air-combustion chamber 711, and the oxygen sprayed from the pure oxygen air distributor 720 forms a bubbling air cushion layer at the bottom of the air-combustion chamber 711. The bubbling air cushion layer can prevent high-temperature powder from being deposited at the bottom of the air-combustion chamber 711, thereby ensuring the normal operation of the air-combustion device 700. In addition, during production, there may be a small amount of sintered granular material at the bottom of the air-combustion chamber 711, and the high-speed airflow sprayed by the pure oxygen air distributor 720 can penetrate the sintered granular material from bottom to top, ensuring that the production process can be carried out stably.

[0089] Reference Figure 7and Fig. 9 In this embodiment, the pure oxygen air distributor 720 is annular, and an annular cavity is formed inside. An inlet is provided on the side wall of the annular cavity, and 30 outlets are evenly distributed along the circumference on the upper end surface of the annular cavity. A first nozzle 760 is provided at the outlet of each pure oxygen air distributor 720. The first nozzle 760 has multiple (specifically 8-10 in this embodiment) spray holes arranged along the circumference, and the spray hole axis has an elevation angle of 15° relative to the horizontal, and the wind speed of the spray hole is 50-60m / s.

[0090] With the above structure, pure oxygen gas enters the pure oxygen air distributor 720 from one side of the pure oxygen air distributor 720, and then is ejected from the plurality of first nozzles 760 and enters the air combustion chamber 711. Since the first nozzles 760 are evenly distributed in an annular shape, and each first nozzle 760 is provided with a plurality of spray holes, the oxygen entering the air combustion chamber 711 forms a relatively uniform spraying gas cushion layer, which not only improves the dispersion of oxygen, but also prevents the deposition of high-temperature powder.

[0091] Continue to refer to Figure 7 The air-combustion device 700 further includes a slag discharge channel 750, which is located at the bottom of the air-combustion chamber 711 and communicates with the air-combustion chamber 711;

[0092] The pure oxygen air distributor 720 is mounted on the slag discharge channel 750 .

[0093] In this embodiment, an electric regulating valve is provided on the slag discharge channel 750, and the residue in the air-combustion chamber 711 can be discharged by controlling the opening and closing degree of the electric flow regulating valve.

[0094] Reference Fig.10 The main burner 730 includes a fuel spray gun 731, a first pulverized coal channel 732, a first oxygen channel 733 and a circulating gas channel 734 which are sequentially mounted from the inside to the outside. The inlet of the circulating gas channel 734 is connected to the outlet of the cooling recovery device 400 through a pipeline.

[0095] Among them, the fuel spray gun 731 is used for ignition and supplementary combustion; the first pulverized coal channel 732 can heat the circulating gas in the circulating gas channel 734 to 900-1700°C, and the wind speed in the first pulverized coal channel 732 is preferably 20-24m / s; the first oxygen channel 733 inputs a small amount of pure oxygen gas through the pipeline and the electric valve on the pipeline to reduce the ignition temperature of the pulverized coal and increase the combustion temperature. The wind speed in the first oxygen channel 733 is preferably 10-15m / s; the circulating gas channel 734 inputs a small amount of circulating gas through the pipeline and the electric valve on the pipeline to absorb the heat in the main burner 730 area, protect the main burner 730 and control the combustion temperature. The wind speed in the circulating gas channel 734 is preferably 10-20m / s.

[0096] Reference Figure 7and Fig.11 The air-fuel shell 710 includes a main pipe extending in a spiral shape and an air intake end plate arranged at the end of the main pipe. A pure oxygen inlet is provided at the bottom of the main pipe, and a circulating gas inlet is provided on the air intake end plate.

[0097] Specifically, the air-fuel shell 710 adopts a three-stage volute structure, and the initial volute variable distance is 0.2D. The main burner 730 and the circulating gas air distributor 740 are both installed on the air inlet end plate of the air-fuel shell 710. The bottom of the air-fuel shell 710 is provided with a plurality of pure oxygen inlets distributed in an annular pattern, and the pure oxygen inlets correspond to and are connected with the outlets of the pure oxygen air distributor 720 one by one. An outlet is provided at the center of the top of the air-fuel shell 710, and the outlet is connected with the gas injection port 110 at the bottom of the decomposition furnace 100.

[0098] Embodiment 3

[0099] Embodiment 3 of the present application provides a carbon dioxide in-situ enrichment process applied to the above-mentioned carbon dioxide in-situ enrichment system, referring to Figure 1 , the process comprises the following steps:

[0100] The circulating gas from the cooling recovery device 400 is divided into multiple branches, one of which is mixed with oxygen from the pure oxygen preparation system and then enters the decomposition furnace 100 through the fuel gas injection port 110, and another branch enters the pulverized coal feeding device 200 as a conveying gas for the pulverized coal;

[0101] The cold raw material and the hot raw material are fed into the decomposition furnace 100 in a certain proportion, and the cold and hot raw materials are mixed with the high-temperature airflow generated by combustion in the decomposition furnace 100 to be decomposed;

[0102] The dusty airflow discharged from the top of the decomposition furnace 100 enters the primary separator 310, and 30-50% of the raw material in the dusty airflow is discharged from the discharge port at the bottom of the primary separator 310 and enters the air lock dust collector 330, and the remaining 50-70% of the raw material continues to enter the secondary separator 320 along with the high-temperature gas;

[0103] 92-95% of the raw meal is discharged from the discharge port at the bottom of the secondary separator 320 and enters the air lock dust collector 330, and the high-temperature gas discharged from the secondary separator 320 enters the cooling recovery device 400;

[0104] The cooling recovery device 400 recovers waste heat and cools the high-temperature gas, and finally outputs carbon dioxide gas with a dry basis concentration of >80%.

[0105] The process provided by the present application is described in detail below with a specific embodiment. The carbonate raw material for decomposition comes from the cement kiln system, and comes from the cold raw material of the cement kiln raw material inlet chute and the hot raw material of the preheater cyclone discharge pipe. The whole process includes the following steps:

[0106] S1: The oxygen from the pure oxygen preparation system is divided into two paths. One path has a concentration of >99% oxygen, which is controlled by gas flow and electric regulating valve, and is mixed with 30-50% volume flow of high-concentration carbon dioxide gas from the outlet of the main exhaust fan 440, and enters the circulating fan to form a mixed gas with an oxygen concentration of 30-50% mainly composed of carbon dioxide / O2, which enters the bottom of the decomposition furnace 100 and the middle and lower part of the decomposition furnace 100 respectively as a combustion-supporting gas for pulverized coal combustion; the remaining 50% of pure oxygen gas in the other path is controlled by a gas flow meter and an electric regulating valve, of which 5% of the volume flow of pure oxygen gas is controlled by a gas flow meter and an electric regulating valve to be used as a combustion-supporting gas at the lower end of the decomposition furnace 100, and about 25% of the volume flow of oxygen with a concentration of >99% is introduced into the annularly arranged nozzles at the lower layer of the decomposition furnace 100, and the remaining about 20% of the volume flow of oxygen with a concentration of >99% is introduced into the annularly arranged nozzles at the upper layer of the decomposition furnace 100 to supplement the oxygen in the decomposition furnace 100;

[0107] Part of the high-concentration carbon dioxide gas from the outlet of the main exhaust fan 440 enters the pulverized coal feeding device 200 and is used as a conveying gas for the pulverized coal to be fed into the decomposition furnace 100;

[0108] The cold raw meal entering the kiln chute passes through the pneumatic gate valve and the electric gate valve, and the opening of the electric gate valve is adjusted to adjust and control the amount of cold and raw meal entering the raw meal bin. After being buffered in the raw meal bin, the cold raw meal is measured by the raw meal scale and enters the middle and lower part of the decomposition furnace 100; the hot raw meal of the preheater cyclone discharge pipe passes through the three-way valve, and the amount of hot raw meal entering the middle and lower part of the decomposition furnace 100 is controlled by adjusting the electric distribution valve plate of the three-way valve and the electric gate valve of the lower material pipe; the hot raw meal enters the decomposition furnace 100, and is mixed and decomposed with the high-temperature airflow generated by the combustion of pulverized coal with the combustion-assisted mixed gas mainly composed of CO2 / O2 from the bottom of the decomposition furnace 100; the ratio of cold and hot raw meal entering the decomposition furnace 100 is adjusted between 0 and 100% according to the temperature control needs of the decomposition furnace 100, and the temperature in the middle of the decomposition furnace 100 is controlled between 900 and 1100°C by adjusting the amount of pulverized coal entering the decomposition furnace 100 and the amount of cold and hot raw meal fed.

[0109] S2: The decomposed raw meal rises to the top of the decomposition furnace 100 along with the air flow, and the high-temperature dust-containing air flow of 850-950°C enters the primary separator 310. 30-50% of the raw meal is separated and passes through the material pipe and the air lock valve and enters the air lock dust collector 330. The remaining 50-70% of the raw meal continues to enter the secondary separator 320 along with the high-temperature gas.

[0110] S3: The secondary separator 320 separates 92-95% of the raw meal and then passes through the material pipe and the air lock valve into the air lock dust collector 330, and then enters the cement kiln decomposition furnace to participate in cement calcination.

[0111] S4: After secondary cyclone separation, the high-temperature gas at 850-900°C and containing dust of 100-200g / m3 enters the waste heat boiler 410 for heat recovery and cooling to 150-180°C. The dust-containing gas is further settled and separated by the waste heat boiler 410 and enters the bag dust collector 420 for dust removal. The dust concentration of the gas at the outlet of the bag dust collector 420 is reduced to <10mg / m3, and then enters the spray cooling system 430 to further cool down to 35-50°C, and reduce the water content in the gas to less than 6%. Finally, the carbon dioxide gas with a dry basis concentration of >80% passes through the main exhaust fan 440 and enters the next carbon dioxide purification and liquefaction system process.

[0112] In summary, the present application separates part of the raw materials and fuel from the cement kiln production line for use in the carbon dioxide in-situ enrichment system, and the high-temperature raw materials that are heated and decomposed are returned to the cement kiln production line for clinker calcination. The waste heat of the high-temperature exhaust gas is recycled and utilized and participates in the carbonate decomposition work in the cement clinker burning process; and, a process for in-situ enrichment of carbon dioxide gas is adopted, and the high-concentration carbon dioxide gas output by the cooling recovery device 400 is used as a combustion-supporting gas, a coal powder conveying gas, and a cleaning gas, and finally a carbon dioxide gas dry basis concentration of >85% is obtained.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon dioxide in-situ enrichment system, characterized in that: The invention comprises a decomposition furnace (100), a pulverized coal feeding device (200), a separation device (300) and a cooling recovery device (400), wherein: a fuel gas injection port (110) is provided at the lower end of the decomposition furnace (100), and a pulverized coal injection port and a raw material injection port are provided on the side wall of the decomposition furnace (100); the pulverized coal feeding device (200) is used to store pulverized coal, and its outlet is connected to the pulverized coal injection port through a pipeline; the separation device (300) is used to perform gas-solid separation on flue gas rich in carbon dioxide; and the cooling recovery device (400) is used to cool the carbon dioxide flue gas; The decomposition furnace (100), the separation device (300) and the cooling recovery device (400) are connected in sequence via pipelines, and the outlet of the cooling recovery device (400) is respectively connected to the fuel gas injection port (110) and the pulverized coal feeding device (200) via pipelines.

2. The carbon dioxide in-situ enrichment system according to claim 1, characterized in that: The cooling recovery device (400) comprises a waste heat boiler (410), a bag dust collector (420), a spray cooling system (430) and a main exhaust fan (440) which are connected in sequence through pipelines, and the inlet of the waste heat boiler (410) is connected to the outlet of the separation device (300) through a pipeline.

3. The carbon dioxide in-situ enrichment system according to claim 2, characterized in that: A dust hopper (450) is provided at the bottom of the waste heat boiler (410) and / or at the bottom of the bag dust collector (420), and at least two material level meters (460) are provided on the dust hopper (450); An ash discharge pipe is provided at the bottom of the ash hopper (450), and a star-shaped discharger (470) is provided on the ash discharge pipe. The star-shaped discharger (470) is interlocked with the material level meter (460) for control.

4. The carbon dioxide in-situ enrichment system according to claim 2, characterized in that: It also includes a blowing device (500), wherein the blowing device (500) includes one or more acetylene deflagration blowers (510) installed on the side wall of the waste heat boiler (410); When there are multiple acetylene deflagration injectors (510), the multiple acetylene deflagration injectors (510) are distributed at intervals along the circumferential direction and / or axial direction of the waste heat boiler (410).

5. The carbon dioxide in-situ enrichment system according to claim 1, characterized in that: It also includes a cleaning pipeline (600), the inlet of which is connected to the outlet of the cooling recovery device or the outlet of the carbon dioxide liquefaction purification system, and the outlet of the cleaning pipeline (600) is connected to the decomposition furnace (100) and the separation device (300).

6. The carbon dioxide in-situ enrichment system according to claim 1, characterized in that: The separation device (300) comprises a primary separator (310), a secondary separator (320) and an air-locking dust collector (330); a discharge port at the bottom of the primary separator (310) and a discharge port at the bottom of the secondary separator (320) are connected to an inlet of the air-locking dust collector (330) via a pipeline; and an outlet of the air-locking dust collector (330) is connected to a cement kiln decomposition furnace (900) via a pipeline.

7. The carbon dioxide in-situ enrichment system according to any one of claims 1 to 6, characterized in that: The invention also comprises an air-fuel device (700), wherein the air-fuel device (700) comprises an air-fuel casing (710) in a volute structure, wherein an air-fuel chamber (711) is formed inside the air-fuel casing (710), wherein an outlet of the air-fuel chamber (711) is connected to the fuel gas injection port (110), and a pure oxygen inlet and a circulating gas inlet are provided on the air-fuel chamber (711), wherein the pure oxygen inlet is used to input oxygen, and the circulating gas inlet is connected to the outlet of the cooling recovery device (400) via a pipeline.

8. The carbon dioxide in-situ enrichment system according to claim 7, characterized in that: The air-fuel device (700) further comprises a main burner (730) and a circulating air distributor (740), wherein: The main burner (730) is arranged on the end surface where the circulating gas inlet is located, and the outlet end of the main burner (730) extends into the air-combustion chamber (711); The circulating air distributor (740) is mounted on the main burner (730), and the inlet of the circulating air distributor (740) is connected to the outlet of the cooling recovery device (400) through a pipeline. The circulating air distributor (740) is provided with a plurality of outlets spaced apart along the circumferential direction, and the number of the circulating air inlets is multiple and corresponds one-to-one with the outlets of the circulating air distributor (740).

9. A process for in-situ enrichment of carbon dioxide, characterized in that: The following steps are involved: The circulating gas from the cooling recovery device (400) is divided into a plurality of branches, one of which is mixed with oxygen from the pure oxygen preparation system and then enters the decomposition furnace (100) through the fuel gas injection port (110), and another branch enters the pulverized coal feeding device (200) as a conveying gas for the pulverized coal; Cold raw materials and hot raw materials are fed into a decomposition furnace (100) in a certain ratio, and the cold raw materials and hot raw materials are mixed with the high-temperature airflow generated by combustion in the decomposition furnace (100) to be decomposed.

10. The in-situ carbon dioxide enrichment process according to claim 9, characterized in that: The following steps are also included: The dust-containing airflow discharged from the top of the decomposition furnace (100) enters the primary separator (310), 30-50% of the raw material in the dust-containing airflow is discharged from the discharge port at the bottom of the primary separator (310) and enters the air lock dust collector (330), and the remaining 50-70% of the raw material continues to enter the secondary separator (320) along with the high-temperature gas; 92-95% of the raw material is discharged from the discharge port at the bottom of the secondary separator (320) and enters the air lock dust collector (330), and the high-temperature gas discharged from the secondary separator (320) enters the cooling recovery device (400); The cooling recovery device (400) recovers waste heat and cools the high-temperature gas, and finally outputs carbon dioxide gas with a dry basis concentration greater than 80%.

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