Cement clinker production system and method for reducing carbon and nitrogen

Abstract

The invention relates to the technical field of cement production, and provides a cement clinker production system capable of reducing carbon and nitrogen, the cement clinker production system comprises a clinker sintering system, the clinker sintering system is provided with a feeding end, a discharging end and an exhaust end, after raw materials enter the clinker sintering system from the feeding end to sinter and form cement clinker, the cement clinker is discharged from the discharging end and discharged from the exhaust end along with circulating gas, and the raw materials are recycled. The exhaust end is connected with a closed dust collector, and the dust collector blocks dust in the circulating gas; the tail end of the discharging end is connected with a clinker warehouse for containing sintered cement clinker; the dust collector is connected with an SCR (Selective Catalytic Reduction) device through a pipeline and is used for treating nitrogen oxides in circulating gas; the tail end of the SCR device is sequentially connected with a first fan, a first heat exchanger and a circulating fan through pipelines; and the circulating fan is respectively connected with the dewatering device, the carbon dioxide trapping system and the chimney. The method has the effects of reducing dust influence and reducing carbon and nitrogen. In addition, the invention also provides a cement clinker production method.

Description

Technical Field

[0001] The present application relates to the technical field of cement manufacturing, and in particular to a cement clinker production system and method for achieving carbon reduction and nitrogen reduction. Background Art

[0002] At present, in the cement production process, raw materials are generally burned into clinker first, and then the clinker is processed to form the final cement product. During the sintering process of cement clinker, a large amount of carbon dioxide and nitrogen oxides will be produced, which will have an immeasurable impact on the environment.

[0003] In the cement industry, the main technologies for carbon emission reduction will include extreme energy efficiency improvement of existing process equipment, low-carbon cement technology based on raw material substitution, fuel substitution to address coal-fired emission issues in the calcination stage, or carbon capture, utilization and storage (CCUS) for end-of-pipe disposal.

[0004] Oxygen-enriched combustion carbon capture refers to the use of a high-concentration mixed gas of oxygen and carbon dioxide to replace air in the kiln to react with coal powder and other fuels. When the cement industry uses oxygen-enriched combustion carbon capture to continuously circulate and enrich the flue gas, the concentration of carbon dioxide in the flue gas continues to increase, thereby reducing the investment and operating costs of the carbon dioxide capture link. However, there will be serious air leakage problems, resulting in a low concentration of carbon dioxide entering the carbon dioxide capture system, which reduces the enrichment combustion effect.

[0005] Similarly, for the reduction of nitrogen oxide emissions, the common practice is to build SCR denitrification based on SNCR. However, due to the high dust concentration and viscosity of cement kiln dust, the high alkali metal content, and the worse operating environment of the catalyst than in the thermal power generation industry, if the design model of SCR in coal-fired power plants is followed completely, the SCR catalyst will inevitably become blocked, worn, poisoned and fail in a short period of time. The dust barrier treatment requires regular cleaning, and a large amount of air will enter, which will reduce the carbon dioxide concentration when used in the oxygen-rich combustion carbon capture system, thereby reducing the carbon dioxide capture efficiency of the system. Summary of the invention

[0006] In order to improve the above-mentioned problems, the present application provides a cement clinker production system and method for achieving carbon reduction and nitrogen reduction.

[0007] The present application provides a cement clinker production system and method for achieving carbon reduction and nitrogen reduction, which adopts the following technical solutions: A cement clinker production system for achieving carbon reduction and nitrogen reduction, comprising the following systems or devices connected by pipelines: The clinker burning system is provided with a feed end, a discharge end and an exhaust end. After the raw material enters the clinker burning system from the feed end and is sintered into cement clinker, it is discharged from the discharge end and generates carbon dioxide and nitrogen oxides. Part of the raw material is discharged from the exhaust end along with the circulating gas. The exhaust end is connected to a sealed dust collector, which blocks the dust in the circulating gas. The end of the discharge end is connected to a clinker storage for containing sintered cement clinker; The dust collector is connected to an SCR device through a pipeline for treating nitrogen oxides in the circulating gas; the end of the SCR device is connected to a first fan, a first heat exchanger and a circulating fan through pipelines in sequence; The circulating fan is connected to the dehydration device, the carbon dioxide capture system and the chimney respectively; the circulating fan delivers a part of the circulating gas which is dehydrated by the dehydration device and then delivered, and the other part of the circulating gas is passed through the carbon dioxide capture system to seal and utilize the carbon dioxide; The water removal device is respectively connected to the second heat exchanger, the air sealing device and the clinker burning system; The circulating gas after water removal contains carbon dioxide, and a part of it enters the second heat exchanger, and the other part enters the clinker burning system for recycling; The second heat exchanger is respectively connected to the air compressor device, the Roots blower and the pulverized coal conveying system; the conveyed circulating gas is connected to the pulverized coal conveying system; the pulverized coal conveying system conveys the calcined pulverized coal and the circulating gas to the clinker burning system through a pipeline; The air separation oxygen production device draws in air to produce oxygen, and transports the oxygen to the clinker burning system to provide oxygen supply for combustion; the air compressor is connected to the ash cleaning system.

[0008] By adopting the above technical scheme, the raw material is sintered into clinker through the clinker burning system, and the generated gas is recycled. The carbon dioxide and nitrogen oxides generated during sintering begin to circulate with the circulating gas. After the dust is filtered by the dust collector of the clinker burning system, the carbon dioxide and nitrogen oxides follow the circulating gas into the SCR device. The SCR device removes nitrogen from the nitrogen oxides, and the carbon dioxide continues to be circulated and transported with the circulating gas, ensuring that the carbon dioxide content in the circulating gas is sufficient to provide oxygen-rich combustion when the circulating gas is recycled, while reducing the external emission of carbon dioxide. The mixed gas of high concentration of oxygen and carbon dioxide replaces air to react with coal powder and other fuels in the clinker burning system, so that the carbon dioxide concentration in the flue gas continues to increase, thereby reducing the investment and operating costs of the carbon dioxide capture link, so as to achieve the production of cement clinker with reduced carbon and nitrogen.

[0009] Optionally, the clinker burning system includes a pressure reamer for conveying raw meal; The preheater assembly blows the circulating gas toward the dust collector, and the dust collector is connected to the preheater assembly pipeline; the pressure reamer is connected to the connecting pipeline between the preheater assembly and the dust collector, and the raw material falls into the preheater assembly, and the dust in the raw material enters the dust collector with the circulating gas for filtration; it includes a second preheater, a third preheater, a fourth preheater and a fifth preheater, which are connected in sequence; The decomposition furnace is connected to the fifth preheater to decompose the raw material; the decomposition furnace is connected to a smoke chamber; The rotary kiln has a kiln head and a kiln tail at both ends. The raw material is sintered in a rotary kiln. The kiln head is provided with a kiln head burner, and the kiln tail is provided with a kiln tail burner. The kiln tail is connected to the decomposition furnace through a smoke chamber. The kiln tail burner is set in the decomposition furnace, and the kiln tail is also connected to the air separation oxygen production device. The kiln head is connected to the kiln head cover and the grate cooler. The kiln head and the kiln tail are both connected to the air separation oxygen production device, and the coal powder conveying system is connected to the kiln head burner and the kiln tail burner respectively. The grate cooler is composed of a first cooling zone, a second cooling zone, and a third cooling zone which are connected in sequence; one end of the first cooling zone is connected to the kiln head, and the other end is connected to the water removal device; one end of the second cooling zone is connected to the water removal device, and the other end is connected to the fifth preheater; the third cooling zone is connected to the clinker storage, and the third cooling zone is connected to the outside world to provide air to enter.

[0010] By adopting the above technical scheme, after the raw meal enters from the pressure reamer, the circulating gas discharged from bottom to top is used to make the dust on the surface of the raw meal blow toward the dust collector along with the circulating gas, so that the dust is collected by the dust collector to avoid damage to the SCR device when removing nitrogen oxides. The raw meal is preheated by a two- to five-stage preheater, partially decomposed by a decomposition furnace, and then sintered into cement clinker by a rotary kiln. Oxygen-enriched combustion is carried out by a kiln head burner and a kiln tail burner to utilize the carbon dioxide in the circulating gas, thereby achieving the environmental protection effect of reducing carbon and nitrogen.

[0011] Optionally, the dust collector adopts a high-box shed structure, including a shell, a shed, a pulse cleaning device, a double-layer inspection door and an air lock valve; the shed is a closed structure, arranged on the upper part of the shell, and a plurality of double-layer inspection doors are arranged on the shed; a closed partition cavity is formed in the middle of the double-layer inspection door, and an air lock valve is arranged at the lower part of the shell.

[0012] By adopting the above technical solution, the circulating air is passed into the partition chamber between the double-layer inspection doors to maintain a slight positive pressure in the partition chamber. Under the action of the slight positive pressure, the outside air cannot enter the partition chamber, that is, it cannot enter the dust collector. The cleaning air of the pulse cleaning device is the circulating air from the air compressor device, which prevents air from entering the system. The closed structure prevents the dust collector from leaking air. The pulse cleaning device can also prevent dust blockage.

[0013] Optionally, the cleaning system includes: an air cannon and a pulse cleaning device; the air cannon is connected to the kiln tail or the fifth preheater by a pipeline; the pulse cleaning device is connected to the dust collector.

[0014] By adopting the above technical solution, the blocked part is flushed away by an air cannon, thereby achieving the purpose of dust cleaning. The pulse cleaning device in the dust collector can remove the dust attached to the dust collector by spraying compressed air to avoid clogging the dust collector.

[0015] Optionally, the air-sealing system comprises: a kiln head sealing device and a kiln tail sealing device; the kiln head sealing device is installed at the kiln head, and the kiln tail sealing device is installed at the kiln tail.

[0016] By adopting the above technical solution, the kiln head sealing device and the kiln tail sealing device are used to isolate the outside air from entering the clinker burning system.

[0017] Optionally, an ammonia water storage tank is also included, and the ammonia water storage tank is respectively connected to the SCR device, the fifth stage preheater and the decomposition furnace.

[0018] By adopting the above technical solution and utilizing the ammonia supply provided by the ammonia storage tank, a portion of the nitrogen oxides can be eliminated, making the removal of the nitrogen oxides more complete.

[0019] A cement clinker production method based on oxygen-enriched combustion to achieve carbon reduction and nitrogen reduction comprises the following steps: The raw material is fed into the system through a pressure reamer at the connection pipe from the second stage preheater to the dust collector, and undergoes heat exchange with the circulating gas rich in high concentration of carbon dioxide in the pipe, and enters the dust collector along with the circulating gas; The raw material is filtered and collected by the dust collector bag and then enters the connecting pipe between the third-stage preheater and the second-stage preheater, and then enters the second preheater after heat exchange with the circulating gas; The raw meal is heat exchanged with the circulating gas in the second to fourth stage preheaters in sequence and then enters the decomposition furnace; After being pre-decomposed in the decomposition furnace, the raw material enters the fifth-stage preheater, is collected by the fifth-stage preheater, and then enters the smoke chamber, and then enters the rotary kiln. After being burned into mature material in the rotary kiln, it enters the first cooling zone of the grate cooler; The clinker is cooled to the required temperature in the first cooling zone, the second cooling zone and the third cooling zone of the grate cooler in turn and then stored in the clinker warehouse; The ammonia in the ammonia storage tank is transported to the SCR device, the fifth-stage preheater and the decomposition furnace respectively; Ammonia water is mixed and homogenized with the circulating gas in the fifth-stage preheater and the decomposition furnace respectively to eliminate some nitrogen oxides; after the circulating gas leaves the dust collector, it is mixed and homogenized with ammonia water from the ammonia water device and enters the SCR device to remove some nitrogen oxides; after the circulating gas leaves the SCR device, it is transported to the first heat exchanger through the first fan, and the circulating gas passes through the circulating fan after heat exchange and temperature reduction in the first heat exchanger; The circulating gas is divided into three routes after passing through the circulating fan: the first circulating gas is purified by the carbon dioxide capture system, and the high-concentration carbon dioxide is obtained for storage or utilization; the second circulating gas is removed from the water by the dehydration device and then continues to be recycled; the third circulating gas enters the chimney for discharge when needed and is closed at other times.

[0020] By adopting the above technical solution, nitrogen oxides can be eliminated and carbon dioxide emissions can be reduced, achieving the environmental protection effect of reducing carbon and nitrogen.

[0021] Optionally, after the circulating gas passes through the water removal device, its direction is divided into four routes. The first route is cooled to room temperature through the second heat exchanger and then goes to the air compressor device, Roots blower and coal powder conveying system respectively; the second route goes to the air sealing system; the third route is mixed with high-concentration oxygen from the air separation oxygen production device and then goes to the first cooling zone of the grate cooler; the fourth route goes to the second cooling zone of the grate cooler.

[0022] By adopting the above technical solution, the moisture content of the circulating gas is reduced after the circulating gas passes through the dehydration device, and the circulating gas can be divided into multiple routes for transportation. The circulating gas with reduced moisture can ensure the stable transportation of coal powder.

[0023] Optionally, the circulating gas after passing through the Roots blower is divided into two paths: the first path is mixed with high-concentration oxygen from the air separation oxygen production device and transported to the kiln tail burner; the second path is mixed with high-concentration oxygen from the air separation oxygen production device as primary air and transported to the kiln head burner.

[0024] By adopting the above technical solution, the pressure of the circulating gas is increased by using a Roots blower, so that the mixing degree of the circulating gas and oxygen is improved and then sent to the kiln tail burner and the kiln head burner respectively.

[0025] Optionally, the circulating air entering the first cooling zone of the grate cooler exchanges heat with the clinker from the rotary kiln and then enters the kiln head hood. Part of the gas in the kiln head hood enters the rotary kiln as secondary air, and part enters the decomposition furnace as tertiary air; the circulating air entering the second cooling zone of the grate cooler exchanges heat with the clinker from the first cooling zone and then enters the decomposition furnace outlet for cooling and air replenishment; in the third cooling zone of the grate cooler, the air and the clinker from the second cooling zone are heat exchanged and then go to the raw material drying system and the coal mill drying system respectively.

[0026] By adopting the above technical solution, the hot air after heat exchange in the third cooling zone is transported to the raw material drying system and the coal mill drying system to recover heat and reduce energy loss, thereby achieving energy saving and environmental protection.

[0027] In summary, the present application includes at least one of the following beneficial technical effects: 1. The raw material is sintered into clinker through the clinker burning system, and the generated gas is recycled. The carbon dioxide and nitrogen oxides generated during sintering begin to circulate with the circulating gas. After the dust is filtered by the dust collector of the clinker burning system, the carbon dioxide and nitrogen oxides follow the circulating gas into the SCR device. The SCR device removes nitrogen from the nitrogen oxides, and the carbon dioxide continues to be transported to ensure that the carbon dioxide content in the circulating gas is sufficient to provide oxygen-rich combustion when the circulating gas is recycled, while reducing the external emission of carbon dioxide. The mixed gas of high concentration of oxygen and carbon dioxide replaces air and reacts with coal powder and other fuels in the clinker burning system, so that the concentration of carbon dioxide in the flue gas continues to increase, thereby reducing the investment and operating costs of the carbon dioxide capture link, so as to achieve the production of cement clinker with reduced carbon and nitrogen; 2. After the raw material enters from the pressure reamer, the circulating gas discharged from bottom to top is used to blow the dust on the surface of the raw material toward the dust collector along with the circulating gas, so that the dust is collected by the dust collector to avoid damage to the SCR device when removing nitrogen oxides. The raw material is preheated by the second to fifth stage preheater, partially decomposed by the decomposition furnace, and then sintered into cement clinker by the rotary kiln. The kiln head burner and the kiln tail burner are used for oxygen-enriched combustion to utilize the carbon dioxide in the circulating gas, so as to achieve the environmental protection effect of reducing carbon and nitrogen; 3. The circulating air is passed into the partition cavity between the double-layer inspection doors to maintain a slight positive pressure in the partition cavity. Under the action of the slight positive pressure, the outside air cannot enter the partition cavity, that is, it cannot enter the dust collector. The pulse cleaning device uses the circulating air from the air compressor device to prevent air from entering the system; the pipeline at the air lock valve is connected to the connecting pipeline between the third-stage preheater and the second-stage preheater, avoiding the problem of high-pressure difference inhaling air; the dust collector does not have the problem of air leakage through structural improvements, and the pulse cleaning device can also prevent dust blockage; 4. Use air cannon to flush the blocked parts to achieve the purpose of cleaning. The pulse cleaning device in the dust collector can remove the dust attached to the dust collector by spraying compressed air to avoid clogging the dust collector. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the process of cement clinker production system in one embodiment of the present application; Figure 2 is a process schematic diagram of a clinker burning system in some embodiments of the present application; Figure 3 is a schematic diagram of the cross-sectional structure of a dust collector in some embodiments of the present application; Figure 4 is a schematic diagram of the side view structure of the dust collector in some embodiments of the present application; The marks in the attached drawings are: 1. clinker burning system, 11. pressure reamer, 12. dust collector, 121. shell, 1211. dust inlet, 1212. air outlet, 1213. spiral fan blade, 122. shed, 123. pulse cleaning device, 124. double-layer inspection door, 125. air lock valve, 126. partition chamber, 127. filter bag, 128. guide cylinder, 1281. transfer ring, 1282. vibration rod, 129. lower ash hopper, 13. preheater assembly, 131. second preheater Heater, 132. Third preheater, 133. Fourth preheater, 134. Fifth preheater, 14. Ammonia storage tank, 15. Decomposition furnace, 16. Rotary kiln, 161. Kiln tail burner, 162. Kiln tail sealing device, 163. Kiln head burner, 164. Kiln head sealing device, 165. Kiln head hood, 17. Grate cooler, 171. First cooling zone, 172. Second cooling zone, 173. Third cooling zone, 18. Air cannon, 19. Smoke chamber, 2. SCR device, 3. Clinker storage. DETAILED DESCRIPTION

[0029] The following is an explanation of the implementation of the present application by specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the information disclosed in the present application. The present application can also be implemented or applied through other different specific implementations, and the details in the present application can also be modified or changed in various ways according to different viewpoints and application systems without departing from the spirit of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0030] The following is a detailed description of the embodiments of the present application with reference to the accompanying drawings so that those skilled in the art can easily implement the present application. The present application can be embodied in a variety of different forms and is not limited to the embodiments described herein.

[0031] In the representations of the present application, the representations with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics represented in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the represented specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples represented in the present application and the features of the different embodiments or examples, unless they contradict each other.

[0032] In addition, the terms "first" and "second" are only used to indicate the target, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the representation of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] Throughout the specification, when a device is said to be "connected" to another device, this includes not only the case of "direct connection" but also the case of "indirect connection" by placing other elements therebetween. In addition, when a device is said to "include" a certain component, unless otherwise stated, it does not exclude other components, but means that other components may be included.

[0034] The following is combined with Figure 1 -Attached Figure 4 , further details of this application are given.

[0035] The embodiments of the present application disclose a cement clinker production system and method for achieving carbon reduction and nitrogen reduction.

[0036] A cement clinker production system for reducing carbon and nitrogen, referring to Figure 1 As shown in the flow chart, the system includes a clinker burning system 1, an SCR device 2, an ammonia water storage tank, a first fan, a first heat exchanger, a circulating fan, a water removal device, an air compressor device, a dust cleaning system, a second heat exchanger, an air sealing system, a pulverized coal conveying system, an air separation oxygen production device, a carbon dioxide capture system and a clinker storage 3 connected by pipelines.

[0037] The utility model comprises a clinker burning system 1, which is provided with a feed end, a discharge end and an exhaust end. The raw material enters the clinker burning system 1 from the feed end, is sintered into cement clinker by a clinker sintering device, and then is discharged from the discharge end. There is circulating gas in the clinker burning system 1, and the generated carbon dioxide and nitrogen oxides are discharged from the exhaust end by utilizing the circulating gas. A dust collector 12 in a sealed state is provided at the exhaust end, and the dust collector 12 filters harmful dust in the circulating gas.

[0038] After the cement clinker at the discharge end is formed, the discharge end is connected to a clinker bin 3 through which the cement clinker is collected.

[0039] After the dust collector 12 filters the dust, there is no or less dust in the remaining circulating gas, so that the circulating gas can be transported to the SCR device 2 through the pipeline. The circulating gas containing carbon dioxide and nitrogen oxides enters the SCR device 2 without the influence of dust. The SCR device 2 can stabilize the nitrogen oxides in the circulating gas, thereby removing the nitrogen oxides in the circulating gas, so that the circulating gas will not contain nitrogen oxides during subsequent circulation, avoiding affecting the subsequent processing flow.

[0040] The end of the SCR device 2 is connected to the first fan, the first heat exchanger and the circulating fan in sequence through pipelines. The first fan conveys the circulating gas to the first heat exchanger to provide sufficient airflow pressure. The first heat exchanger performs heat exchange and cooling on the circulating gas, and then the circulating gas enters the circulating fan. The circulating fan provides the air pressure for subsequent gas transportation.

[0041] The circulating fan is respectively connected to the dehydration device, the carbon dioxide capture system and the chimney. The circulating fan transports a part of the circulating gas which is dehydrated by the dehydration device and then transported, and the other part of the circulating gas is passed through the carbon dioxide capture system to seal and utilize the carbon dioxide.

[0042] Another part can be discharged from the chimney. The chimney is usually closed. When necessary, the chimney is opened to discharge part of the circulating gas.

[0043] The circulating gas pipeline is also connected to an air separation oxygen production device, which draws in air to produce oxygen, and transports the oxygen to the clinker burning system 1 to provide oxygen supply for oxygen-enriched combustion.

[0044] The dehydration device is respectively connected to the second heat exchanger, the air sealing device and the clinker burning system 1, so that the circulating gas is divided into three paths after passing through the dehydration device. The first path is cooled to room temperature through the second heat exchanger and then goes to the air compressor device, the Roots blower and the pulverized coal conveying system respectively. The compressed circulating gas after passing through the air compressor device is used as the air source of the ash cleaning system. The circulating gas after passing through the Roots blower is mixed with the oxygen from the air separation oxygen generator and transported to the clinker burning system 1. Different combustion flame forms are obtained by adjusting the ratio of the circulating gas and the high-concentration oxygen. The pulverized coal conveying system uses the circulating gas to transport the pulverized coal to the clinker burning system 1, and uses the pulverized coal and oxygen for calcination energy supply.

[0045] The circulating gas after dehydration is degassed in the second route through the sealing system, and is mixed with high-concentration oxygen from the air separation oxygen generator in the third route and then directly transported to the clinker burning system 1, so that the circulating gas is repeatedly recycled.

[0046] Specifically, the raw material is sintered into clinker by the clinker burning system 1, and the generated gas is recycled. The carbon dioxide and nitrogen oxides generated during sintering begin to circulate with the circulating gas. After the dust is filtered by the dust collector 12 of the clinker burning system 1, the circulating gas enters the SCR device 2. The SCR device 2 removes nitrogen from the nitrogen oxides. Subsequently, the circulating gas containing carbon dioxide passes through the first fan and the circulating fan through pressurization, the first heat exchanger and the second heat exchanger through cooling, and enters the air compressor device and the pulverized coal conveying system. The air compressor device mixes the carbon dioxide with the oxygen produced by the air separation oxygen production device at high pressure and transports it. The pulverized coal conveying system transports the pulverized coal and the circulating gas to the clinker burning system 1 simultaneously. The high-concentration oxygen and carbon dioxide mixed gas replaces air and reacts with pulverized coal and other fuels in the clinker burning system 1 to continuously increase the carbon dioxide concentration in the flue gas, thereby ensuring that the carbon dioxide content is sufficient to provide oxygen-rich combustion when the carbon dioxide is recycled. At the same time, the external emission of carbon dioxide is reduced, and the effect of recycling is achieved, thereby reducing the investment and operating costs of the carbon dioxide capture link, so as to achieve the production of cement clinker with reduced carbon and nitrogen.

[0047] For further reference, Figure 2 As shown, the clinker burning system 1 includes a grate cooler 17, a rotary kiln 16, a kiln head burner 163, a kiln head hood 165, a smoke chamber 19, a decomposition furnace 15, a kiln tail burner 161, a preheater group 13, a dust collector 12, a pressure reamer 11 and an air cannon 18, wherein the grate cooler 17 includes a first cooling zone 171, a second cooling zone 172 and a third cooling zone 173, and the third cooling zone 173 is connected to the clinker zone.

[0048] The raw meal is transported through a pressure reamer 11 at the connecting pipeline from the second-stage preheater to the dust collector 12. The dust collector 12 is a high-temperature dust collector 12, which can filter dust in the raw meal. The filtered circulating gas enters the SCR device 2.

[0049] The preheater assembly 13 is divided into a second preheater 131, a third preheater 132, a fourth preheater 133 and a fifth preheater 134, and the second preheater 131, the third preheater 132, the fourth preheater 133 and the fifth preheater 134 are connected in sequence. The preheater group 13 can blow the circulating gas toward the high-temperature dust collector 12. When the pressure reamer 11 is connected to the connecting pipe between the preheater assembly 13 and the high-temperature dust collector 12, the raw material directly falls into the second preheater 131 assembly, and the dust in the raw material enters the dust collector 12 with the circulating gas for filtration. The raw material in the circulating gas is filtered and collected by the filter bag of the high-temperature dust collector 12 and then enters the connecting pipe between the third-stage preheater and the second-stage preheater.

[0050] In the preheater group 13, each preheater includes a cyclone to provide air flow supply for circulating gas.

[0051] The decomposition furnace 15 is connected to the fifth preheater 134, and the decomposition furnace 15 is connected to the smoke chamber 19. After the raw material is pre-decomposed in the decomposition furnace 15, it enters the fifth preheater, and then enters the smoke chamber 19 after being collected by the fifth preheater. The smoke chamber 19 is connected to the rotary kiln 16, so the decomposed raw material enters the rotary kiln 16 from the smoke chamber 19, and enters the first cooling zone 171 of the grate cooler 17 after being burned into mature material in the rotary kiln 16.

[0052] The two ends of the rotary kiln 16 are respectively a kiln head and a kiln tail. The raw material is rotated and sintered in the rotary kiln 16. A kiln head burner 163 is provided at the kiln head, and a kiln tail burner 161 is provided at the kiln tail. The kiln tail is connected to the decomposition furnace 15 through a smoke chamber 19. The kiln tail burner 161 is arranged in the decomposition furnace 15. The kiln tail is also connected to an air separation oxygen production device. The air separation oxygen production device converts air into oxygen and transports it to the kiln tail. The oxygen is combined with coal powder through the kiln tail burner 161 to carry out oxygen-enriched combustion.

[0053] The kiln head is connected to the kiln head cover 165 and the grate cooler 17; the kiln head and the kiln tail are both connected to the air separation oxygen production device, and the pulverized coal conveying system is respectively connected to the kiln head burner 163 and the kiln tail burner 161; The grate cooler 17 cools and transports the cement clinker and provides hot air for the rotary kiln 16 and the decomposition furnace 15. The grate cooler 17 is composed of a first cooling zone 171, a second cooling zone 172 and a third cooling zone 173 which are connected in sequence. One end of the first cooling zone 171 is connected to the kiln head, and the other end is connected to the dehydration device. One end of the second cooling zone 172 is connected to the dehydration device, and the other end is connected to the fifth preheater 134. The third cooling zone 173 is connected to the clinker storage 3, and the third cooling zone 173 is connected to the outside world to provide air to enter, and utilizes the air to exchange heat with the already formed cement clinker to reduce the temperature of the cement clinker.

[0054] Specifically, the raw meal is transported by the pressure reamer 11. During the transport process, the circulating gas dust collecting box is blown in the direction of the preheater group 13, so that the lighter raw meal and dust follow the circulating gas into the dust collector 12. The dust collector 12 is used to filter the lighter raw meal and dust, and the generated carbon dioxide and nitrogen oxides continue to enter the SCR device 2 with the circulating gas for denitrification. After the nitrogen oxides reach a certain amount, the excess raw meal enters the third preheater 132 from the dust collector 12 and is then transported to the decomposition furnace 15. After the raw material is pre-decomposed in the decomposition furnace 15, it enters the fifth-stage preheater, is collected in the fifth-stage preheater, and then enters the smoke chamber 19, and then enters the rotary kiln 16. After being burned into clinker in the rotary kiln 16, it enters the first cooling zone 171 of the grate cooler 17. The clinker is cooled to the required temperature in the first cooling zone 171, the second cooling zone 172, and the third cooling zone 173 of the grate cooler 17 in sequence, and then enters the clinker warehouse 3 for storage. The clinker burning system 1 cooperates with the circulating gas to separate the raw material from the dust, so that the dust is greatly reduced and enters the SCR device 2.

[0055] Further, refer to Figure 3 and Figure 4 As shown, the dust collector 12 adopts a high-box shed 122 structure, including a shell 121, a shed 122, a pulse cleaning device 123, a double-layer inspection door 124 and a wind lock valve 125; the shed 122 is a closed structure, which is arranged on the upper part of the shell 121. A plurality of double-layer inspection doors 124 are arranged on the shed 122, and materials can only enter and exit from the double-layer inspection doors 124 on the shed 122.

[0056] A closed partition chamber 126 is formed in the middle of the double-layer inspection door 124, and circulating air is passed into the partition chamber 126 between the double-layer inspection door 124 to maintain a slight positive pressure in the partition chamber 126, which may be around 5 Pa. Under the action of the slight positive pressure, outside air cannot enter the partition chamber 126, that is, it cannot enter the high-temperature dust collector 12. A double-layer air lock valve 125 is provided at the lower part of the shell 121, and the double-layer air lock valve 125 is connected to the connecting pipe between the third-stage preheater and the second-stage preheater. The cleaning air of the pulse cleaning device 123 is the circulating air from the air compressor device to prevent air from entering the system. The closed structure prevents the dust collector 12 from leaking air, and the pulse cleaning device 123 can also prevent dust blockage.

[0057] Among them, a plurality of filter bags 127 are arranged in the shell 121 , and the filter bags 127 absorb and filter the dust. A guide cylinder 128 is arranged between the filter bags 127 , and a plurality of transfer rings 1281 are arranged on the outer wall of the guide cylinder 128 , and the transfer rings 1281 are in contact with the filter bags 127 .

[0058] A vibration rod 1282 is provided in the guide tube 128. Both the guide tube 128 and the vibration rod 1282 are made of metal, so that when the two are in contact, a vibration effect will be generated. The vibration rod 1282 is in contact with the inner wall of the guide tube 128, and the transfer ring 1281 provides transmission of the vibration effect when the vibration rod 1282 vibrates.

[0059] A dust inlet 1211 is provided on one side of the shell 121, and an air outlet 1212 is provided on the other side. A connecting frame and a spiral fan blade 1213 are provided at the air outlet 1212; a pivot bearing is provided on the connecting frame (the connecting frame and the pivot bearing are not shown in the figure), and the spiral fan blade 1213 is pivotally connected to the pivot bearing; the dust inlet 1211 conveys circulating air into the shell 121, which is filtered through the filter bag 127. A plurality of lower ash hoppers 129 are provided at the bottom of the shell 121. The lower ash hoppers 129 are connected to the pipelines between the third preheater 132 and the second preheater 131, so that after the dust on the filter bag 127 is accumulated and cleaned by the pulse cleaning device 123, it can be returned to the third preheater 132 through the lower ash hopper 129 for recycling. When the accumulated dust needs to be returned to the third preheater 132, the double-layer air lock valve 125 needs to be opened.

[0060] A vibration pattern is provided on the surface of the vibration rod 1282, and one end of the vibration rod 1282 is connected to the axis of the spiral fan blade 1213, so that when the spiral fan blade 1213 rotates, it drives the vibration rod 1282 to rotate. The vibration rod 1282 contacts the inner wall of the guide cylinder 128 using the vibration pattern, thereby providing a vibration effect. The vibration effect can cooperate with the transfer ring 1281 to shake off part of the dust accumulated on the filter bag 127, and the pulse cleaning device 123 can remove a certain amount of accumulated dust without being turned on regularly, thereby extending the interval time of regular cleaning, and at the same time extending the service life of the filter bag 127 and reducing the required replacement frequency. The spiral fan blade 1213 does not need to be driven additionally, and the airflow from the spiral fan blade 1213 is used to rotate the spiral fan blade 1213. During the rotation, the vibration rod 1282 can be driven to rotate to achieve the vibration effect.

[0061] The reason why the spiral fan blade 1213 is located at the air outlet 1212 is that the air outlet 1212 is not affected by dust, while dust is easily accumulated if it is set at the dust inlet 1211, making it difficult for the spiral fan blade 1213 to rotate.

[0062] The inner wall of the guide cylinder 128 may also be provided with vibration patterns, and the two vibration patterns are in contact, so that the vibration effect is more obvious. The vibration patterns may be spiral, and the vibration patterns on the inner wall of the guide cylinder 128 and the vibration patterns on the outer wall of the vibration rod 1282 have opposite spiral directions to avoid mutual clamping, so that the vibration rod 1282 cannot rotate. In some embodiments, the dust cleaning system includes: an air cannon 1818 and a pulse dust cleaning device 123123. The air cannon 1818 is connected to the kiln tail or the fifth preheater 134134 by a pipeline. When a blockage occurs at the kiln tail or in the preheater group 13, the air cannon 1818 is used to flush the blocked part, thereby achieving the dust cleaning effect.

[0063] The pulse cleaning device 123 in the dust collector 12 can remove the dust attached to the dust collector 12 by blowing compressed air, avoiding clogging of the dust collector 12, which would reduce the filtering effect of the dust collector 12 and affect the filtering of dust and the emission of nitrogen oxides.

[0064] The dust cleaning system also includes a pipeline system connecting various dust cleaning points. For example, the air cannon 18 can directly impact the connected pipeline systems synchronously to disperse the blockage or dust in the pipeline and discharge it into the dust collector 12 with the circulating gas.

[0065] In some embodiments, the airtight sealing system includes: a kiln head sealing device 164, a kiln tail sealing device 162 and improved inspection doors, valves, holes, and covers throughout the system. The airtight sealing system also includes a pipeline system connecting each sealing point, and each connection point is provided with a separate sealing structure to ensure that the pipeline can provide a stable transmission of circulating gas.

[0066] The kiln head sealing device 164 is installed at the kiln head, and the kiln tail sealing device 162 is installed at the kiln tail. The kiln head sealing device 164 adopts a double-layer fish scale sealing structure, and the kiln tail sealing device 162 adopts a double-layer sealing structure of compression sealing and fish scale sealing. The function of the kiln head sealing device 164 and the kiln tail sealing device 162 is to isolate the outside air from entering the clinker burning system 1.

[0067] In some embodiments, an ammonia water storage tank is also included, and the ammonia water storage tank is respectively connected to the SCR device 2, the fifth-stage preheater and the decomposition furnace 15. The ammonia water is respectively mixed and homogenized with the circulating gas in the fifth-stage preheater and the decomposition furnace 15 to eliminate some of the nitrogen oxides. After the circulating gas leaves the high-temperature dust collector 12, it is mixed and homogenized with the ammonia water from the ammonia water storage tank 14 and enters the SCR device 2 to remove some of the nitrogen oxides. The ammonia water supply provided by the ammonia water storage tank can eliminate some of the nitrogen oxides, making the removal of nitrogen oxides more sufficient and complete.

[0068] The present application also provides a production method provided by a cement clinker production system for achieving carbon reduction and nitrogen reduction based on oxygen-enriched combustion in the above-mentioned embodiment, Figure 1 and Figure 2 As shown, the following steps are included: The raw material is introduced into the system through a pressure reamer 11 at the connecting pipe from the second-stage preheater to the high-temperature dust collector 12, and exchanges heat with the circulating gas rich in high-concentration carbon dioxide in the pipeline, and enters the high-temperature dust collector 12 with the circulating gas.

[0069] When the pressure reamer 11 is working, the interior is filled with raw material, and the raw material is pushed into the system by the spiral blades, that is, the air is isolated from entering the system in the form of a material seal.

[0070] The raw meal is filtered and collected by the filter bag of the high-temperature dust collector 12 and then enters the connecting pipe between the third-stage preheater and the second-stage preheater, and then enters the second preheater 131 after heat exchange with the circulating gas therein.

[0071] The raw meal sequentially exchanges heat with the circulating gas in the second to fourth stage preheaters and then enters the decomposition furnace 15. The raw meal is preheated in multiple stages by the preheater group 13 to reach a temperature that is convenient for decomposition.

[0072] The raw material is pre-decomposed in the decomposition furnace 15 and then enters the fifth-stage preheater. After being collected by the fifth-stage preheater, it enters the smoke chamber 19 and then enters the rotary kiln 16. After being burnt into mature material in the rotary kiln 16, it enters the first cooling zone 171 of the grate cooler 17. The clinker is cooled to the required temperature in the first cooling zone 171, the second cooling zone 172 and the third cooling zone 173 of the grate cooler 17 in sequence and then enters the clinker storage 3 for storage.

[0073] Among them, the first cooling zone 171 and the second cooling zone 172 are connected to the circulating gas that has been cooled and lowered by the first heat exchanger and the second heat exchanger. Therefore, the cooled circulating gas can cool the cement clinker in the first cooling zone 171 and the second cooling zone 172, and the third cooling zone 173 is connected to the outside world, so the outside air can cool the third cooling zone 173. After cooling in the three cooling zones, the temperature of the cement clinker reaches the collection standard.

[0074] Among them, the third cooling zone 173 can be connected to the exhaust pipe, and the exhaust pipe transports the hot air cooled by the third cooling zone 173 to the raw material drying system and the coal mill drying system to recover heat and reduce energy loss to achieve energy saving and environmental protection.

[0075] The ammonia water in the ammonia water storage tank is respectively transported to the SCR device 2, the fifth stage preheater and the decomposition furnace 15; Ammonia water is mixed and homogenized with the circulating gas in the fifth-stage preheater and the decomposition furnace 15 respectively to eliminate some nitrogen oxides therein. After the circulating gas leaves the high-temperature dust collector 12, it is mixed and homogenized with ammonia water from the ammonia water device and enters the SCR device 2 to remove some nitrogen oxides, so that the NOx content in the circulating gas leaving the SCR device 2 is less than 50 mg / m3. After leaving the SCR device 2, the circulating gas is transported to the first heat exchanger through the first fan. After heat exchange and cooling in the first heat exchanger, the circulating gas passes through the circulating fan.

[0076] After the circulating gas passes through the circulating fan, the dry basis concentration of carbon dioxide is greater than 80%, and its direction is divided into three routes: the first circulating gas is purified by the carbon dioxide capture system to obtain high-concentration carbon dioxide, which is then sealed or utilized; the second circulating gas is passed through the dehydration device to remove part of the moisture and then continues to be recycled; the third circulating gas enters the chimney for evacuation when needed and is closed at other times.

[0077] The temperature of the circulating gas after some of the moisture is removed by the dehydration device is 75-80℃, and its direction is divided into four routes. The first route is cooled to room temperature through the second heat exchanger and then goes to the air compressor device, Roots blower and coal powder conveying system respectively; the second route goes to the air sealing system; the third route is mixed with the high-concentration oxygen from the air separation oxygen production device and then goes to the first cooling zone 171 of the grate cooler 17; the fourth route goes to the second cooling zone 172 of the grate cooler 17.

[0078] The compressed circulating air after passing through the air compressor device is used as the air source of the cleaning system, including the ash cleaning by the air cannon 18 of the sintering system and the ash cleaning by the pulse cleaning device 123 of the high-temperature dust collector 12.

[0079] After passing through the Roots blower, the circulating gas is divided into two paths: the first path is mixed with the high-concentration oxygen from the air separation oxygen production device and transported to the kiln tail burner 161; the second path is mixed with the high-concentration oxygen from the air separation oxygen production device as primary air and transported to the kiln head burner 163. Different combustion flame forms can be obtained by adjusting the ratio of circulating gas and high-concentration oxygen.

[0080] The pulverized coal conveying system utilizes circulating gas to pneumatically convey the pulverized coal to the kiln tail burner 161 and the kiln head burner 163 respectively.

[0081] The circulating air entering the first cooling zone 171 of the grate cooler 17 exchanges heat with the clinker from the rotary kiln 16 and then enters the kiln head hood 165. The gas temperature in the kiln head hood 165 is 950-1250°C. Part of it enters the rotary kiln 16 as secondary air, and part of it goes to the decomposition furnace 15 as tertiary air; the circulating air entering the second cooling zone 172 of the grate cooler 17 exchanges heat with the clinker from the first cooling zone 171 and has a temperature of 400-500°C, and then enters the outlet of the decomposition furnace 15 for cooling and air replenishment; in the third cooling zone 173 of the grate cooler 17, the air and the clinker from the second cooling zone 172 are heat exchanged to become hot air at 200-250°C, and the hot air goes to the raw material drying system and the coal mill drying system respectively.

[0082] During oxygen-enriched combustion, since the raw meal is in a high carbon dioxide atmosphere, to achieve the same decomposition rate as under air combustion conditions, the decomposition temperature of the raw meal in the decomposition furnace 15 must be increased by 80-100°C. To avoid equipment crusting, the decomposition furnace 15 is provided with a kiln tail burner 161 with a pre-combustion chamber structure. The circulating gas carries the pulverized coal into the pre-combustion chamber first, and the excess coefficient of oxygen in the pre-combustion chamber is 0.6. The pulverized coal is first gasified and pyrolyzed into combustibles such as carbon monoxide, hydrogen and methane in the pre-combustion chamber, and then enters the decomposition furnace 15, and a part of the tertiary air, that is, the tertiary air split air is sprayed into the decomposition furnace 15 in an annular shape, which holds the combustibles for rapid combustion and avoids high-temperature crusting on the side wall of the decomposition furnace 15.

[0083] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A cement clinker production system for achieving carbon reduction and nitrogen reduction, characterized in that: The system or device comprises the following pipeline connections: a clinker burning system (1), which is provided with a feed end, a discharge end and an exhaust end. After the raw material enters the clinker burning system (1) from the feed end and is sintered to form cement clinker, it is discharged from the discharge end and generates carbon dioxide and nitrogen oxides. Part of the raw material is discharged from the exhaust end along with the circulating gas. The exhaust end is connected to a sealed dust collector (12), and the dust collector (12) blocks dust in the circulating gas. The end of the discharge end is connected to a clinker storage (3) for containing sintered cement clinker; The dust collector (12) is connected to an SCR device (2) via a pipeline for treating nitrogen oxides in the circulating gas; the end of the SCR device (2) is connected to a first fan, a first heat exchanger and a circulating fan via pipelines in sequence; The circulating fan is connected to the dehydration device, the carbon dioxide capture system and the chimney respectively; the circulating fan delivers a part of the circulating gas which is dehydrated by the dehydration device and then delivered, and the other part of the circulating gas is passed through the carbon dioxide capture system to seal and utilize the carbon dioxide; The water removal device is respectively connected to the second heat exchanger, the air sealing device and the clinker burning system (1); The circulating gas after water removal contains carbon dioxide, and a part of it enters the second heat exchanger, and the other part enters the clinker burning system (1) for recycling; The second heat exchanger is respectively connected to the air compressor device, the Roots blower and the pulverized coal conveying system; the conveyed circulating gas is connected to the pulverized coal conveying system; the pulverized coal conveying system conveys the calcined pulverized coal and the circulating gas to the clinker burning system (1) through a pipeline; The air separation oxygen production device draws in air to produce oxygen, and transports the oxygen to the clinker burning system (1) to provide oxygen supply for combustion; wherein the air compressor is connected to a dust cleaning system.

2. A cement clinker production system for achieving carbon reduction and nitrogen reduction according to claim 1, characterized in that: The clinker burning system (1) comprises a pressure reamer (11) for conveying raw materials; The preheater assembly (13) blows the circulating gas toward the dust collector (12); the pressure reamer (11) is connected to the connecting pipe between the preheater assembly (13) and the dust collector (12); the raw material falls into the preheater assembly (13); and the dust in the raw material enters the dust collector (12) with the circulating gas for filtration; the preheater assembly (13) comprises a second preheater (131), a third preheater (132), a fourth preheater (133) and a fifth preheater (134), which are connected in sequence; The decomposition furnace (15) is connected to the fifth preheater (134) to decompose the raw material; the decomposition furnace (15) is connected to a smoke chamber (19); A rotary kiln (16) having a kiln head and a kiln tail at two ends, respectively, wherein raw materials are sintered by rotation in the rotary kiln (16), wherein a kiln head burner (163) is provided at the kiln head, and a kiln tail burner (161) is provided at the kiln tail; the kiln tail is connected to a decomposition furnace (15) through a smoke chamber (19), the kiln tail burner (161) is arranged at the decomposition furnace (15), and the kiln tail is also connected to an air separation oxygen production device; the kiln head is connected to a kiln head cover (165) and a grate cooler (17); the kiln head and the kiln tail are both connected to the air separation oxygen production device, and a pulverized coal conveying system is respectively connected to the kiln head burner (163) and the kiln tail burner (161); The grate cooler (17) is composed of a first cooling zone (171), a second cooling zone (172), and a third cooling zone (173) which are connected in sequence; one end of the first cooling zone (171) is connected to the kiln head, and the other end is connected to the water removal device; one end of the second cooling zone (172) is connected to the water removal device, and the other end is connected to the fifth preheater (134); the third cooling zone (173) is connected to the clinker storage (3), and the third cooling zone (173) is in communication with the outside to provide air for entry.

3. A cement clinker production system for achieving carbon reduction and nitrogen reduction according to claim 2, characterized in that: The dust collector (12) adopts a high-box shed (122) structure, comprising a shell (121), a shed (122), a pulse dust cleaning device (123), a double-layer inspection door (124) and a wind lock valve (125); the shed (122) is a closed structure, arranged on the upper part of the shell (121), and a plurality of double-layer inspection doors (124) are arranged on the shed (122); a closed partition chamber (126) is formed in the middle of the double-layer inspection door (124), and a wind lock valve (125) is arranged at the lower part of the shell (121).

4. A cement clinker production system for achieving carbon reduction and nitrogen reduction according to claim 3, characterized in that: The dust cleaning system comprises: an air cannon (18) and a pulse dust cleaning device (123); the air cannon (18) is connected to the kiln tail or the fifth preheater (134) by means of a pipeline; and the pulse dust cleaning device (123) is connected to the dust collector (12).

5. A cement clinker production system for achieving carbon reduction and nitrogen reduction according to claim 2, characterized in that: The airtight sealing system comprises: a kiln head sealing device (164) and a kiln tail sealing device (162); the kiln head sealing device (164) is installed at the kiln head, and the kiln tail sealing device (162) is installed at the kiln tail.

6. A cement clinker production system for achieving carbon reduction and nitrogen reduction according to any one of claims 1 to 5, characterized in that: It also includes an ammonia water storage tank, which is respectively connected to the SCR device (2), the fifth stage preheater and the decomposition furnace (15).

7. A method for producing cement clinker, characterized in that: The cement clinker production system applied to claim 6 comprises the following steps: The raw material is introduced into the system through a pressure reamer (11) at the connection pipe between the second-stage preheater and the dust collector (12), and undergoes heat exchange with the circulating gas rich in high-concentration carbon dioxide in the pipe, and enters the dust collector (12) along with the circulating gas; The raw material is filtered and collected by the filter bag of the dust collector (12) and then enters the connecting pipe between the third-stage preheater and the second-stage preheater, and then enters the second preheater (131) after heat exchange with the circulating gas therein. The raw meal is heat exchanged with the circulating gas in the second to fourth stage preheaters in sequence and then enters the decomposition furnace (15); The raw material is pre-decomposed in the decomposition furnace (15) and then enters the fifth-stage preheater. After being collected by the fifth-stage preheater, it enters the smoke chamber (19), and then enters the rotary kiln (16). After being burnt into clinker in the rotary kiln (16), the raw material enters the first cooling zone (171) of the grate cooler (17); The clinker is sequentially cooled to a required temperature in the first cooling zone (171), the second cooling zone (172), and the third cooling zone (173) of the grate cooler (17) and then enters the clinker storage (3) for storage; The ammonia water in the ammonia water storage tank is respectively transported to the SCR device (2), the fifth stage preheater and the decomposition furnace (15); The ammonia water is mixed and homogenized with the circulating gas in the fifth stage preheater and the decomposition furnace (15) respectively, thereby eliminating some nitrogen oxides therein; after the circulating gas leaves the dust collector (12), it is mixed and homogenized with the ammonia water from the ammonia water device, and then enters the SCR device (2) to remove some nitrogen oxides; after the circulating gas leaves the SCR device (2), it is transported to the first heat exchanger through the first fan, and the circulating gas passes through the circulating fan after heat exchange and temperature reduction in the first heat exchanger; The circulating gas after passing through the circulating fan is divided into three routes: the first route of circulating gas is purified by the carbon dioxide capture system, and the high-concentration carbon dioxide is obtained and then sealed or utilized; The second circulating gas continues to be recycled after some moisture is removed by the dehydration device; the third circulating gas enters the chimney for discharge when needed and is closed at other times.

8. A cement clinker production method according to claim 7, characterized in that: After the circulating gas passes through the dehydration device, its direction is divided into four routes. The first route is cooled to room temperature through the second heat exchanger and then goes to the air compressor device, the Roots blower and the coal powder conveying system respectively; the second route goes to the gas sealing system; the third route is mixed with the high-concentration oxygen from the air separation oxygen production device and then goes to the first cooling zone (171) of the grate cooler (17); the fourth route goes to the second cooling zone (172) of the grate cooler (17).

9. A cement clinker production method according to claim 7, characterized in that: After passing through the Roots blower, the circulating gas is divided into two paths: the first path is mixed with the high-concentration oxygen from the air separation oxygen production device and transported to the kiln tail burner (161); the second path is mixed with the high-concentration oxygen from the air separation oxygen production device as primary air and transported to the kiln head burner (163).

10. A cement clinker production method according to claim 7, characterized in that: The circulating air entering the first cooling zone (171) of the grate cooler (17) exchanges heat with the clinker from the rotary kiln (16) and then enters the kiln head hood (165). Part of the gas in the kiln head hood (165) enters the rotary kiln (16) as secondary air, and part of the gas enters the decomposition furnace (15) as tertiary air; the circulating air entering the second cooling zone (172) of the grate cooler (17) exchanges heat with the clinker from the first cooling zone (171) and then enters the outlet of the decomposition furnace (15) for cooling and air replenishment; in the third cooling zone (173) of the grate cooler (17), the air exchanges heat with the clinker from the second cooling zone (172) and then goes to the raw material drying system and the coal mill drying system respectively.

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