阅读说明：本技术 局部钙循环与纯氧燃烧耦合的水泥生产碳捕集装置及工艺 (Cement production carbon capture device and process with local calcium circulation and pure oxygen combustion coupled ) 是由 张同生 汪伟 郭奕群 韦江雄 余其俊 于 2021-04-08 设计创作，主要内容包括：本发明公开了一种局部钙循环与纯氧燃烧耦合的水泥生产碳捕集装置及工艺,包括预热器-碳化炉-回转窑模块、纯氧燃烧分解炉模块以及辅助与纯化装置,预热器-碳化炉-回转窑模块包括生料进料装置、第一系列旋风预热器、碳化炉、第二系列旋风预热器、烟室、回转窑、三次风管、回转窑燃烧器以及冷却机；纯氧燃烧分解炉模块包括分解炉、分解炉燃烧器、第三系列旋风预热器以及增压风机；辅助与纯化装置包括第一SNCR装置、第二SNCR装置、分风装置、第一分料装置、第二分料装置、第一换热装置、第二换热装置、冷凝除水装置、CO-(2)收集与储存装置、除尘装置、SCR装置、烟气排出装置；通过模块化分离与耦合,降低CO-(2)捕集与利用难度,具有良好的经济性。(The invention discloses a cement production carbon capture device and process with local calcium circulation and pure oxygen combustion coupling, which comprises a preheater-carbonization furnace-rotary kiln module, a pure oxygen combustion decomposing furnace module and an auxiliary and purifying device, wherein the preheater-carbonization furnace-rotary kiln module comprises a raw material feeding device, a first series of cyclone preheaters, a carbonization furnace, a second series of cyclone preheaters, a smoke chamber, a rotary kiln, a tertiary air pipe, a rotary kiln combustor and a cooler; the pure oxygen combustion decomposing furnace module comprises a decomposing furnace, a decomposing furnace burner, a third series of cyclone preheaters and a booster fan; the auxiliary and purifying device comprises a first SNCR device, a second SNCR device, a wind distribution device, a first material distribution device, a second material distribution device, a first heat exchange device, a second heat exchange device, a condensation and dehydration device, and a CO (carbon monoxide) purifying device 2 The device comprises a collecting and storing device, a dust removing device, an SCR device and a flue gas discharging device; CO reduction through modular separation and coupling 2 Difficulty in trapping and utilization and good economical efficiency.)

1. Local calcium circulation and pure oxygen combustion coupled cement production carbon trapping device, its characterized in that, including pre-heater-carbide furnace-rotary kiln module, pure oxygen combustion decomposing furnace module and supplementary and purification device, pre-heater-carbide furnace-rotary kiln module includes raw material feed arrangement (21), a series of cyclone pre-heater (1), carbide furnace (4), the secondThe device comprises a second series of cyclone preheaters (2), a smoke chamber (7), a rotary kiln (8), a tertiary air pipe (25), a rotary kiln combustor (9) and a cooler (10); the pure oxygen combustion decomposing furnace module comprises a decomposing furnace (13), a decomposing furnace burner (14), a third series of cyclone preheaters (3) and a booster fan (20); the auxiliary and purifying device comprises a first SNCR device (5), a second SNCR device (6), an air distribution device (15), a first material distribution device (11), a second material distribution device (12), a first heat exchange device (16), a second heat exchange device (17), a condensation and water removal device (18), CO₂A collecting and storing device (19), a dust removing device (22), an SCR device (23) and a flue gas discharging device (24);

the tertiary air pipe (25) is connected with an outlet of the smoke chamber (7), an air inlet of the second series of cyclone preheaters (2) is connected with the smoke chamber (7), an air inlet of the carbonization furnace (4) is connected with the second series of cyclone preheaters (2), an air inlet of the first series of cyclone preheaters (2) is connected with an air outlet of the carbonization furnace (4), and an air outlet of the first series of cyclone preheaters (1) is sequentially connected with the second heat exchange device (17), the dust removal device (22) and the SCR device (23); the air outlet of the decomposing furnace (13) is connected with the air inlet of a third series of cyclone preheaters (3), the air outlet of the third series of cyclone preheaters (3) is connected with an air distribution device (15), one outlet of the air distribution device (15) is connected with a booster fan (20) and is connected with the air inlet of the decomposing furnace (13), and the other outlet of the air distribution device (15) is connected with a first heat exchange device (16), a condensation and water removal device (18) and a CO (carbon monoxide) water removal device (18)₂The collection and storage device (19) are connected in sequence;

the discharge hole of the penultimate cyclone separator of the first series of cyclone preheaters (1) is connected with the carbonization furnace (4), the discharge hole of the penultimate cyclone separator of the first series of cyclone preheaters (1) is connected with the air inlet pipe of the second series of cyclone preheaters (2), the discharge hole of the second series of cyclone preheaters (2) is connected with the decomposing furnace (13) through a second material distributing device (12), the decomposing furnace (13) is connected with the feeding hole of the third series of cyclone preheaters (3), the discharge hole of the third series of cyclone preheaters (3) is connected with the kiln tail of the carbonization furnace (4) and the rotary kiln (8) through a first material distributing device (11), the air inlet of the decomposing furnace (13) is connected with a second SNCR device (6), the air inlet of the second series of cyclone preheaters (2) is connected with a first SNCR device (5), the lower part of the smoke chamber (7) is connected with the kiln tail of the rotary kiln (8), the kiln head of the rotary kiln (8) is connected with a rotary kiln combustor (9) and a cooler (10).

2. The local calcium circulation and pure oxygen combustion coupled cement production carbon capture device of claim 1, characterized in that: the number of stages of cyclone separators of the first series of cyclone preheaters (1) is 4-7, the number of stages of cyclone separators of the second series of cyclone preheaters (2) is 1-2, and the number of stages of cyclone separators of the third series of cyclone preheaters (3) is 1-2.

3. The local calcium circulation and pure oxygen combustion coupled cement production carbon capture device of claim 1, characterized in that: the carbonization furnace (4) is provided with a multi-stage necking structure, and a feeding hole is formed above each stage of necking structure.

4. The local calcium circulation and pure oxygen combustion coupled cement production carbon capture device of claim 1, characterized in that: the decomposing furnace (13) is provided with a multi-stage necking structure, and a feeding hole is formed above each stage of necking structure.

5. The trapping process of the cement production carbon trapping device with the coupling of local calcium circulation and pure oxygen combustion is characterized by comprising the following steps of:

a raw material feeding device (21) is arranged at an air inlet of a first cyclone separator of the first series of cyclone preheaters (1), and raw materials and flue gas enter a carbonization furnace (4) in a second last-stage cyclone separator of the first series of cyclone preheaters (1);

the raw materials enter a first-stage cyclone separator at the last but one of a first series of cyclone preheaters (1) after passing through a carbonization furnace (4), then enter a second series of cyclone preheaters (2) together with the gas at the outlet of a smoke chamber (7), and are respectively sprayed with hot raw materials at different parts of a decomposing furnace (13) through a second material distributing device (12);

decomposing furnace burners (14) are arranged at different parts of the decomposing furnace (13) and are used for injecting fuel and oxygen; NOx in the flue gas is removed by adopting a second SNCR device (6), and then the flue gas enters a third series of cyclone preheaters (3) for gas-solid separationAfter separation, the flue gas enters a wind separation device (15) and is divided into two paths, one path of flue gas passes through a first heat exchange device (16) and a condensation water removal device (18) in sequence to obtain high-purity CO₂To the CO₂The other path of the gas is accelerated by a booster fan (20) and enters the decomposing furnace (13) again to participate in gas circulation;

raw materials are decomposed in the pure oxygen combustion decomposing furnace module to generate a large amount of CaO, the CaO enters the third series of cyclone preheaters (3) along with gas, after gas-solid separation, the materials are divided into two paths through the first material distribution device (11), one path of CaO enters the carbonization furnace (4) to realize local calcium circulation between the carbonization furnace (4) and the decomposing furnace (13), and the other path of CaO enters the kiln tail of the rotary kiln (8) to participate in clinker sintering.

Technical Field

The invention relates to the technical field of crossing cement production and calcium circulation carbon capture, in particular to a device and a process for capturing carbon in cement production by coupling local calcium circulation and pure oxygen combustion.

Background

Along with the rapid development of national economy, Chinese CO₂The emission is increased year by year, the emission reaches 94.3 hundred million tons in 2017, wherein the cement industry is CO in China₂One of the major sources of emissions (about 20.0 million tons per year, about 21%). Therefore, the pressure of carbon emission reduction in China is extremely high, and the reduction of carbon emission in the cement industry is particularly important and urgent.

Carbon emission reduction in the cement industry is mainly realized by purifying and trapping flue gas, and the current main trapping process comprises the following steps: chemical absorption, membrane separation, pure oxygen combustion, and calcium circulation. The chemical absorption method is that the flue gas of the cement kiln is pressurized, and then hot potassium solution, ammonia water or organic amine and other liquid are adopted to absorb CO₂Then the water is desulfurized and removed by a desulfurizing bed and a drying bed, and phosphorus, arsenic and Nitrogen Oxides (NO) are removed by a solid adsorbent_x) The impurities are equal, and the industrial grade or food grade CO is finally obtained₂. The membrane separation method is to utilize the selectivity of the membrane to the diameter of gas molecules, and part of the gas passes through the molecular membrane under certain pressure, so as to realize the enrichment and separation of CO 2. The pure oxygen combustion method is to improve the combustion efficiency of fuel, reduce NOx emission and greatly improve CO in flue gas by oxygen combustion supporting₂Concentration for carbon capture. The calcium circulation law is that CaO abundantly existing in the cement kiln system is utilized to absorb CO₂Formation of CaCO₃And then decomposing again in the decomposing furnace to release CO2 and capturing, namely through CaO-CaCO₃Circulation of-CaO for CO in cement kiln flue gas₂Self-enrichment of (1).

In summary, a large amount of chemical reagents and membrane materials are needed when the chemical absorption and membrane separation method is adopted for carbon capture, and the flue gas is required to be pressurized and decompressed, so that the carbon capture cost is greatly increased. In addition, the cement kiln has large flue gas flow and high dust and acid gas content, and the membrane separation method is difficult to continuously carry out CO with high flux₂The separation and purification greatly shorten the cycle life of the absorbent. In comparison, the pure oxygen combustion method and the calcium circulation method fully utilize the characteristics of fuel and the high calcium characteristic of the cement kiln system, and can improve CO in the flue gas of the cement kiln from the source₂The concentration of the carbon dioxide is greatly reduced, the difficulty in treating and capturing the tail end of the cement kiln smoke is greatly relieved, and the carbon capture potential is strong. Because the activity is sharply reduced and the circulation efficiency is low in the calcium circulation process, and the cost of the pure oxygen environment of the whole system of the cement kiln is extremely high, the popularization and the application of the pure oxygen combustion and calcium circulation process in the field of the capture of the flue gas carbon of the cement kiln are hindered.

Disclosure of Invention

In order to solve the technical problems mentioned in the background technology, the invention provides a device and a process for capturing carbon in cement production, wherein local calcium circulation and pure oxygen combustion are coupled.

The technical scheme adopted by the invention is as follows: a cement production carbon capture device with local calcium circulation and pure oxygen combustion coupling comprises a preheater-carbonization furnace-rotary kiln module, a pure oxygen combustion decomposing furnace module and an auxiliary and purification device, wherein the preheater-carbonization furnace-rotary kiln module comprises a raw material feeding device, a first series of cyclone preheaters, a carbonization furnace, a second series of cyclone preheaters, a smoke chamber, a rotary kiln, a tertiary air pipe, a rotary kiln combustor and a cooler; the pure oxygen combustion decomposing furnace module comprises a decomposing furnace, a decomposing furnace burner, a third series of cyclone preheaters and a booster fan; the auxiliary and purifying device comprises a first SNCR device, a second SNCR device, a wind distribution device, a first material distribution device, a second material distribution device, a first heat exchange device, a second heat exchange device, a condensation and dehydration device, and CO₂The device comprises a collecting and storing device, a dust removing device, an SCR device and a flue gas discharging device;

the third air pipe is connected with the outlet of the smoke chamber, the air inlet of the second series of cyclone preheaters is connected with the smoke chamber, the air inlet of the carbonization furnace is connected with the second series of cyclone preheaters, the air inlet of the first series of cyclone preheaters is connected with the air outlet of the carbonization furnace, and the air outlet of the first series of cyclone preheaters is sequentially connected with the second heat exchange device, the dust removal device and the SCR device; air outlet of decomposing furnace and air inlet of third series cyclone preheaterThe openings of the first and second series of cyclone preheaters are connected, the air outlet of the third series of cyclone preheaters is connected with an air distribution device, one outlet of the air distribution device is connected with a booster fan and is connected with the air inlet of the decomposing furnace, and the other outlet of the air distribution device is connected with a first heat exchange device, a condensation water removal device and a CO (carbon monoxide) heat exchanger₂The collection and storage devices are connected in sequence;

the discharge port of the penultimate cyclone separator of the first series of cyclone preheaters is connected with the carbonization furnace, the discharge port of the penultimate cyclone separator of the first series of cyclone preheaters is connected with the air inlet pipe of the second series of cyclone preheaters, the discharge port of the second series of cyclone preheaters is connected with the decomposing furnace through a second material distributing device, the decomposing furnace is connected with the feeding port of the third series of cyclone preheaters, the discharge port of the third series of cyclone preheaters is connected with the carbonization furnace and the kiln tail of the rotary kiln through a first material distributing device, the air inlet of the decomposing furnace is connected with a second SNCR device, the air inlet of the second series of cyclone preheaters is connected with a first SNCR device, the lower part of a smoke chamber is connected with the kiln tail of the rotary kiln, and the kiln head of the rotary kiln is connected with a burner and a cooler of the rotary kiln.

The method has the following beneficial effects: the pure oxygen combustion decomposing furnace module and the preheater-carbide furnace-rotary kiln module are designed in a separated mode, and are simultaneously coupled with the local calcium circulation of the decomposing furnace-carbide furnace, CaO generated by the decomposing furnace is partially fed into the carbide furnace to efficiently trap CO₂Then the carbon-fixing product CaCO3 is conveyed to a decomposing furnace to complete CO₂Releasing, realizing the high-efficiency capture and ultrahigh concentration self-enrichment of CO2 in the flue gas of the cement kiln, and reducing the subsequent CO₂Difficulty in trapping and utilization, good economical efficiency and convenient popularization. In addition, by the separated design of the pure oxygen combustion decomposing furnace module and the preheater-carbonization furnace-rotary kiln module, on one hand, volatile substances such as chlor-alkali sulfur and the like generated in the rotary kiln cannot enter the decomposing furnace; on the other hand, SO released by decomposition of sulfide in raw material in the first series of preheaters₂When the impurity gas can not enter the decomposing furnace, the pure oxygen combustion decomposing furnace module can obtain the CO with ultrahigh concentration and purity₂The difficulties of subsequent purification, utilization and the like are further reduced by the smoke.

Furthermore, the number of stages of cyclone separators of the first series of cyclone preheaters is 4-7, the number of stages of cyclone separators of the second series of cyclone preheaters is 1-2, and the number of stages of cyclone separators of the third series of cyclone preheaters is 1-2.

Further, the carbide furnace has multistage throat structure, and every grade of throat structure top all is provided with the feed inlet.

Furthermore, the decomposing furnace is provided with a multi-stage necking structure, and a feeding hole is formed above each stage of necking structure.

A trapping process of a cement production carbon trapping device with local calcium circulation and pure oxygen combustion coupled comprises the following steps:

a raw material feeding device is arranged at an air inlet of a first cyclone separator of the first series of cyclone preheaters, and raw materials and flue gas enter a carbonization furnace at a penultimate cyclone separator of the first series of cyclone preheaters;

the raw materials enter a first-stage cyclone separator at the last stage of the first series of cyclone preheaters after passing through the carbonization furnace, then enter a second series of cyclone preheaters together with the gas at the outlet of the smoke chamber, and are respectively sprayed with hot raw materials at different parts of the decomposing furnace through a second material distribution device;

setting burners of the decomposing furnace at different positions of the decomposing furnace, and injecting fuel and oxygen; removal of NO from flue gas using a second SNCR apparatus_xThen enters a third series of cyclone preheaters, after gas-solid separation, the flue gas enters an air separation device and is divided into two paths, and one path of flue gas sequentially passes through a first heat exchange device and a condensation dewatering device to obtain high-purity CO₂To the CO₂The other path of the gas is accelerated by a booster fan and enters the decomposing furnace again to participate in gas circulation;

raw materials are decomposed in the pure oxygen combustion decomposing furnace module to generate a large amount of CaO, the CaO enters a third series of cyclone preheaters along with gas, after gas-solid separation, the materials are divided into two paths through a first material distribution device, one path enters the carbonization furnace to realize local calcium circulation between the carbonization furnace and the decomposing furnace, and the other path enters the kiln tail of the rotary kiln to participate in clinker sintering.

Drawings

The invention is further illustrated with reference to the following figures and examples:

FIG. 1 is a block diagram of a cement production carbon capture device with local calcium circulation coupled with pure oxygen combustion.

Description of reference numerals: 1-a first series of cyclone preheaters, 2-a second series of cyclone preheaters, 3-a third series of cyclone preheaters, 4-a carbonization furnace, 5-a first SNCR device, 6-a second SNCR device, 7-a smoke chamber, 8-a rotary kiln, 9-a rotary kiln burner, 10-a cooler, 11-a first material dividing device, 12-a second material dividing device, 13-a decomposition furnace, 14-a decomposition furnace burner, 15-a wind dividing device, 16-a first heat exchange device, 17-a second heat exchange device, 18-a condensation water removal device, 19-CO₂The device comprises a collecting and storing device, a booster fan 20, a raw material feeding device 21, a dust removal device 22, an SCR device 23, a flue gas discharging device 24 and a tertiary air pipe 25.

Detailed Description

Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

The terms appearing below are explained first:

SNCR: selective non-catalytic reduction; SCR: and (4) selective catalytic reduction.

Referring to fig. 1, an embodiment of the present invention provides a cement production carbon capture device with a local calcium circulation coupled with pure oxygen combustion, and the cement production carbon capture device with a local calcium circulation coupled with pure oxygen combustion includes a first series of cyclone preheaters 1, a second series of cyclone preheaters 2, a third series of cyclone preheaters 3, a carbonization furnace 4, a first SNCR device 5, a second SNCR device 6, a smoke chamber 7, a rotary kiln 8, a rotary kiln combustor 9, a cooler 10, a first material distribution device 11, a second material distribution device 12, a decomposition furnace 13, a decomposition furnace combustor 14, a wind distribution device 15, a first heat exchange device 16, a second heat exchange device 17, a condensation and water removal device 18, a CO₂The device comprises a collecting and storing device 19, a booster fan 20, a raw material feeding device 21, a dust removal device 22, an SCR device 23, a flue gas exhaust device 24 and a tertiary air pipe 25. The number of the cyclone separators of the first series of cyclone preheaters 1 is 4, the number of the cyclone separators of the second series of cyclone preheaters 2 is 1, and the number of the cyclone separators of the third series of cyclone preheaters 3 is 1.

In the cement production carbon catching device with local calcium circulation and pure oxygen combustion coupled, the outlet of the tertiary air pipe 25 is connected with the outlet of the smoke chamber 7; the air inlet of the second series of cyclone preheaters 2 is connected with the smoke chamber 7; an air inlet of the carbonization furnace 4 is connected with an air outlet of the second series of cyclone preheaters 2; the air inlet of the first series of cyclone preheaters 1 is connected with the air outlet of the carbonization furnace 4; the air outlet of the first series of cyclone preheaters 1 is connected with the second heat exchange device 17, the dust removal device 22, the SCR device 23 and the flue gas discharge device 24 in sequence.

The air outlet of the decomposing furnace 13 is connected with the air inlet of the third series of cyclone preheaters 3; outlet of the third series cyclone preheater 3The air port is connected with an air distributing device 15; one outlet of the air distribution device 15 is connected with a booster fan 20 and is connected with an air inlet of the decomposing furnace 13; the other outlet of the air distribution device 15 is connected with a first heat exchange device 16, a condensation and dehydration device 18 and CO₂The collection and storage means 19 are in turn connected.

Raw materials are fed into an air inlet pipe of a first-stage cyclone separator of the first series of cyclone preheaters 1 through a raw material feeding device 21, and a discharge port of a penultimate second-stage cyclone separator of the first series of cyclone preheaters 1 is connected with a carbonization furnace 4; the discharge port of the first-to-last cyclone separator of the first series of cyclone preheaters 1 is connected with the air inlet pipe of the second series of cyclone preheaters 2; the discharge port of the second series of cyclone preheaters 2 is connected with a decomposing furnace 13 through a second material distributing device 12; the outlet of the decomposing furnace 13 is connected with the air inlet pipe of the third series of cyclone preheaters 3, and the discharge port of the third series of cyclone preheaters 3 is respectively connected with the carbonization furnace 4 and the kiln tail of the rotary kiln 8 through a first material distributing device 11; the air inlet of the decomposing furnace 13 is connected with the second SNCR device 6, and the air inlet of the second series cyclone preheater 2 is connected with the first SNCR device 5; the lower part of the smoke chamber 7 is connected with the kiln tail of the rotary kiln 8, and the kiln head of the rotary kiln is connected with a rotary kiln combustor 9 and a cooler 10.

The carbon capture process for cement production by coupling local calcium circulation and pure oxygen combustion comprises the following steps: cement raw materials enter an air inlet pipeline of a first-stage cyclone separator of the first series of cyclone preheaters 1, the heat exchange between the raw materials and flue gas fully occurs in the first series of cyclone preheaters 1, and the heat exchange is further carried out after the raw materials enter a carbonization furnace 4 from a third-stage cyclone separator of the first series of cyclone preheaters 1; after gas-solid separation of the flue gas by the fourth-stage cyclone separator of the first series of cyclone preheaters 1, hot raw materials enter the air inlet pipeline of the second series of cyclone preheaters 2, the air inlet temperature of the carbonization furnace 4 is further reduced through heat exchange, and a foundation is laid for improving the carbonization reaction rate and efficiency. In addition, the sulfides contained in the raw meal are decomposed by heat during the preheating process to release SO2 to be discharged with the flue gas, SO that the high-purity CO can be obtained in the subsequent decomposing furnace 13₂Reduction of SO₂And the content of impurity gases.

In this embodiment, the decomposing furnace 13 has four stages of throat structures, except the last stage of throat structure, a feed inlet is arranged above each stage of throat structure, and hot raw material passing through the second series of cyclone preheaters 2 is fed in through the second material distributing device 12 at multiple points to improve the decomposition rate and efficiency of calcium carbonate.

A second distribution device 12 is arranged in the line connecting the second series of cyclone preheaters 2 to the decomposing furnace 14 for adjusting the amount of hot raw meal entering different parts of the decomposing furnace 13.

Preferably, the decomposing furnace 13 is provided with decomposing furnace burners 14 at different positions for injecting fuel and oxygen so that the decomposing furnace 13 is in a locally pure oxygen combustion state.

The decomposing furnace burners 14 are all positioned above the necking structures of the stages (except the last stage) of the decomposing furnace 13 and are lower than the feed inlet for injecting fuel and oxygen.

Decomposition of hot raw meal in a pure oxygen combustion decomposing furnace module to produce a large amount of CO₂Small amount of thermal and fuel NO_xRemoving by adopting an SNCR (selective non catalytic reduction) denitration device, after gas-solid separation by a third series of cyclone preheaters 3, enabling the flue gas to enter an air distribution device 15 and be divided into two paths, and sequentially passing one path through a first heat exchange device 16 and a condensation water removal device 18 to obtain high-purity CO₂To the CO₂A collection and storage device 19; the other path of the gas enters the decomposing furnace 13 again through the booster fan 20 to participate in gas circulation.

The air distribution device 15 is arranged at the air outlet of the third series of cyclone preheaters 3 and is used for adjusting the air entering the pure oxygen combustion decomposing furnace module and the CO₂The amount of gas in the collection and storage device 19.

According to the embodiment, after gas-solid separation is carried out on hot raw materials containing a large amount of CaO by a third series of cyclone preheaters 3, the hot raw materials are divided into two paths by a first material distribution device 11, the first path is fed into an air inlet pipe of a carbonization furnace 4, the hot raw materials are quickly carbonized in a flue gas environment at the temperature of 600-850 ℃, and CO2 in the flue gas is captured by local calcium circulation between the carbonization furnace 4 and a decomposing furnace 13. The second path is fed into the kiln tail of the rotary kiln 8 and enters the rotary kiln 8 to participate in the burning of clinker.

The carbonization furnace 4 has a multi-stage necking structure, and gas-solid full contact is realized through multiple times of spouting, so that the carbonization rate and efficiency are improved.

The discharged flue gas of the carbonization furnace 4 enters the first-stage wind cyclone of the first series of preheaters 1And in the separator, hot raw materials after gas-solid separation are fed into an air inlet pipe of the second series preheater 2, and enter the decomposing furnace 13 after heat exchange with high-temperature flue gas discharged from the smoke chamber. The heat exchange can reduce the temperature of the flue gas entering the carbonization furnace, is favorable for accelerating the carbonization reaction rate in the carbonization furnace, and improves the CO capture by local calcium circulation₂The efficiency of (c).

Compared with the prior art, the invention has the following advantages and effects:

1) the pure oxygen combustion decomposing furnace module and the preheater-carbide furnace-rotary kiln module are designed in a separated mode, and are simultaneously coupled with the local calcium circulation of the decomposing furnace-carbide furnace, CaO generated by the decomposing furnace is partially fed into the carbide furnace to efficiently capture CO₂Then adding CaCO as a carbon-fixing product₃Transferring to a decomposing furnace to complete CO₂Releasing to realize CO in the flue gas of the cement kiln₂The high-efficiency capture and the ultrahigh concentration self-enrichment of the carbon dioxide reduce the subsequent CO₂Difficulty in trapping and utilization, good economical efficiency and convenient popularization.

2) The pure oxygen combustion decomposing furnace module and the preheater-carbonization furnace-rotary kiln module are designed in a separated mode, so that volatile substances such as chlor-alkali sulfur and the like generated in the rotary kiln cannot enter the decomposing furnace module; on the other hand, SO released by decomposition of sulfide in raw material in the first series of preheaters₂When the impurity gas can not enter the decomposing furnace module, the pure oxygen combustion decomposing furnace module can obtain the CO with ultrahigh concentration and purity₂The difficulties of subsequent purification, utilization and the like are further reduced by the smoke.

3) The decomposing furnace adopts a multi-stage necking structure design, exerts the spouting effect to make the materials fully contact with the combustion-supporting gas, improves the combustion efficiency and improves the CO₂The generation amount is controlled, the generation of NO and CO is controlled, and the temperature field in the decomposing furnace is uniformly distributed by utilizing the multi-stage combustion of hot raw materials, fuel and oxygen, so that the local overheating is avoided, and the operation safety of equipment is ensured.

4) Hot raw meal subjected to heat exchange in the first series of cyclone preheaters 1 is fed into an air inlet pipe of the second series of cyclone preheaters 2, and the temperature of the raw meal is further improved through gas-solid heat exchange, so that the temperature difference between the hot raw meal and the environment of the decomposing furnace is reduced, the heat efficiency is improved, and the method is also favorable for improving the heat efficiencyThe consumption of fuel and oxygen of the decomposing furnace is reduced; on the other hand, the flue gas entering the carbonization furnace 4 is cooled, raw materials are fed into the carbonization furnace 4 at multiple points, the heat released by carbonization is absorbed through heat exchange, the temperature of the flue gas is reduced, and therefore CaCO in the carbonization furnace 4 is reduced₃The resolubility of the catalyst improves the carbonization reaction rate and ensures CO in the carbonization furnace₂High efficiency of trapping.

5) SNCR denitration devices are arranged at the air outlets of the decomposing furnace 13 and the smoke chamber 7, so that NO in smoke is reduced_xThe content of impurity gas is equal, thereby ensuring CO in the flue gas₂The concentration of the active carbon is high;

6) the amount of CaO entering the local calcium circulation of the carbonization furnace 4 and the rotary kiln is regulated and controlled by utilizing a material distribution device at the outlet of the third series of cyclone preheaters 3, the high-activity CaO entering the calcium circulation system is dynamically updated, and the effect of CaO on CO is maintained₂The absorption activity of the calcium carbonate realizes the calcium circulation to CO₂The continuous and high-efficiency trapping effect is achieved.

In summary, the invention realizes CO in the cement kiln system by matching the material with the temperature field based on the gas-solid flow direction and the dynamic characteristics of the cement kiln system₂Trapping and self-enriching fully excavate the potential of the cement kiln flue gas carbon trapping technology coupling local pure oxygen combustion and local calcium circulation, and realize CO in the cement kiln flue gas₂The high concentration self-enrichment is beneficial to resource utilization of the cement kiln flue gas, and is convenient for promoting energy conservation and emission reduction of the cement industry.

While the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.