System for coupling oxygen-enriched combustion with combustible gas denitration of cement kiln and control method thereof

Abstract

The invention belongs to a cement kiln oxygen-enriched combustion coupling combustible gas denitration system in the technical field of energy conservation and carbon reduction of industrial kilns. The invention further relates to a control method of the cement kiln oxygen-enriched combustion coupling combustible gas denitration system. A gas outlet of the gasification furnace (1) is communicated with an inlet of the cyclone separator (4), and an oxygen supply pipeline (5) is arranged on the conveying pipeline (2); a cyclone separator (4) is arranged below the preheater (6), and a discharge port of the preheater (6) is communicated with a feed port of the cyclone separator (4); or a calcium-based waste feeding component (7) is arranged above the cyclone separator (4), and the calcium-based waste feeding component (7) is communicated with the cyclone separator (4). According to the system and method for coupling oxygen-enriched combustion with combustible gas denitration of the cement kiln, fly ash carried by the combustible gas can be separated, and chloride ions in the combustible gas can be adsorbed and separated; meanwhile, oxygen-enriched combustion in the rotary kiln is achieved, the combustion efficiency of the rotary kiln is improved, and the calcining capacity in the rotary kiln is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy conservation and carbon reduction of industrial kilns, and more specifically, relates to a system for coupling oxygen-enriched combustion with combustible gas denitrification in a cement kiln. The present invention also relates to a control method for the system for coupling oxygen-enriched combustion with combustible gas denitrification in a cement kiln. Background Art

[0002] The use of energetic solid wastes such as RDF, tires, and biomass as alternative fuels has become the most concerned carbon emission reduction technology in the cement industry. At present, the cement industry mostly adopts the method of directly injecting alternative fuels into the decomposition furnace when using alternative fuels. On the one hand, due to the fluctuation of the quality of alternative fuels, it is easy to cause unstable thermal working conditions of cement kilns; on the other hand, because alternative fuels often contain harmful elements such as chlorine, it is easy to cause a large amount of crusting in the decomposition furnace, which limits the use of alternative fuels. Although cement companies currently often use bypass ventilation to alleviate the problems in the use of the above-mentioned alternative fuels, bypass ventilation is prone to heat waste, and at the same time, it does not fundamentally solve the problem of using a large proportion of alternative fuels in cement kiln systems.

[0003] In the prior art, there is a technology named "equipment for coal-fired kiln raw material fuel replacement, chlorine removal, denitrification and coordinated solid waste disposal" and the publication (announcement) number is "CN117229795A". This technology belongs to the field of clean, low-carbon energy efficient utilization technology for preparing renewable energy from solid waste, and specifically relates to a multifunctional equipment for coal-fired kiln raw material fuel replacement, chlorine removal, denitrification and coordinated solid waste disposal, including a continuous rotary arch-breaking boiling gasification furnace device, a secondary combustion and gas-solid separation device, a circulating cooling device and a control system. During the shutdown of the cement kiln, the solid waste substitute fuel is in an aerobic full combustion working state, and the residue produced after combustion can be used as a cement production admixture or a raw material for cement clinker production. When the solid waste substitute fuel is burned in anoxic or oxygen-poor reduction, a high-temperature combustible gas with reducing properties is generated. The high-temperature combustible gas enters the cement kiln decomposition furnace and the pre-decomposition system, reducing the generation of nitrogen oxides in the cement kiln decomposition furnace and the pre-decomposition system. At the same time, the reducing atmosphere can be burned in the cement kiln system to generate heat, which can reduce the amount of coal used. The prior art does not involve the technical problems and technical solutions of this application. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to provide a cement kiln with a simple structure, which can reliably separate the fly ash carried by the combustible gas entering the cyclone separator from the gasifier, and also realize the adsorption separation of chloride ions in the combustible gas generated by the gasifier; at the same time, high-purity oxygen is prepared and mixed with the low-temperature exhaust gas at the kiln head to form oxygen-enriched air with high oxygen concentration, so as to make full use of the waste heat at the kiln head, and a part of the oxygen-enriched air is sent to the gasifier as a gasifying agent to replace the fuel to produce combustible gas, and the other part of the oxygen-enriched air is mixed with the low-temperature exhaust gas or air at the kiln head to form low-concentration oxygen-enriched air, so as to realize the oxygen-enriched combustion of the alternative fuel or pulverized coal at the kiln head, improve the combustion efficiency of the rotary kiln, and improve the calcination capacity in the kiln. The oxygen-enriched combustion coupled combustible gas denitrification system.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is:

[0006] The present invention relates to a system for oxygen-enriched combustion coupled with combustible gas denitrification in a cement kiln, wherein an air inlet of a gasifier is connected to a kiln head of a rotary kiln through a conveying pipeline, an air outlet of the gasifier is connected to an inlet of a cyclone separator, and an oxygen supply pipeline is arranged on the conveying pipeline; a cyclone separator is arranged below a preheater, and a material outlet of the preheater is connected to a material inlet of the cyclone separator; or, a calcium-based waste delivery component is arranged above the cyclone separator, and the calcium-based waste delivery component is connected to the cyclone separator.

[0007] The preheater discharge port is connected to the cyclone separator feed port, and the preheater is connected to the decomposition furnace; or, the calcium-based waste delivery component is connected to the cyclone separator, and the cyclone separator is connected to the decomposition furnace.

[0008] When the preheater discharge port is connected to the cyclone separator feed port, the cyclone separator is configured to be a structure capable of separating fly ash carried by the combustible gas entering the cyclone separator from the gasifier, and the cement raw meal partially decomposed by the preheater is configured to be a structure capable of entering the cyclone separator, and adsorbing and separating chloride ions in the combustible gas entering the cyclone separator from the gasifier.

[0009] When the calcium-based waste delivery component is connected to the cyclone separator, the cyclone separator is configured to have a structure capable of separating fly ash carried by the combustible gas entering the cyclone separator from the gasifier, and the calcium-based waste delivered by the calcium-based waste delivery component into the cyclone separator is configured to have a structure capable of adsorbing and separating chloride ions in the combustible gas entering the cyclone separator from the gasifier.

[0010] When the preheater discharge port is connected to the cyclone separator feed port, the preheater discharge port is connected to the cyclone separator feed port through a pipeline, and a valve is arranged on the pipeline.

[0011] When the calcium-based waste delivery component is connected to the cyclone separator, the calcium-based waste in the calcium-based waste delivery component is red mud or white mud or carbide slag or cement raw material.

[0012] When the preheater discharge port is connected to the cyclone separator feed port, the CaO content in the cement raw material transported from the preheater to the cyclone separator is not less than 63%.

[0013] The conveying pipeline is connected to the burner of the rotary kiln through the burner connecting pipeline. The mixed gas in the conveying pipeline close to the gasifier is mixed gas a, and the mixed gas in the burner connecting pipeline close to the burner is mixed gas b. The oxygen concentration of mixed gas a is 40-45%; the oxygen concentration of mixed gas b is 30-40%.

[0014] When the gasifier air inlet is connected to the rotary kiln head through a delivery pipeline, the oxygen injection pressure of the oxygen supply pipeline is 20kpa-40kpa; the pressure of the kiln head exhaust gas is 10kpa-20kpa; the purity of oxygen is 65%-99.999%.

[0015] The present invention also relates to a control method for a system of cement kiln oxygen-enriched combustion coupled with combustible gas denitration, characterized in that the control steps of the control method for the system of cement kiln oxygen-enriched combustion coupled with combustible gas denitration are as follows:

[0016] S1. The mixed gas in the delivery pipeline near the gasifier is mixed gas a, which is delivered to the gasifier, and the mixed gas in the burner connecting pipeline 9 near the burner is mixed gas b, which is delivered to the burner. The oxygen concentration of the mixed gas a is 40-45%; the oxygen concentration of the mixed gas b is 30-40%;

[0017] S2. When the preheater discharge port is connected to the cyclone separator feed port, the cyclone separator separates the fly ash carried by the combustible gas entering the cyclone separator from the gasifier, and the cement raw meal partially decomposed by the preheater enters the cyclone separator, and the chloride ions in the combustible gas generated by the gasifier are adsorbed and separated, and the fly ash is discharged from the cyclone separator; or, when the calcium-based waste delivery component is connected to the cyclone separator, the cyclone separator separates the fly ash carried by the gasifier, and the calcium-based waste delivered to the cyclone separator by the calcium-based waste delivery component adsorbs and separates the chloride ions in the combustible gas entering the cyclone separator from the gasifier, and the fly ash is discharged from the cyclone separator;

[0018] S3. The combustible gas is sent to the cone reduction zone of the decomposition furnace, and the reducing gas in the combustible gas is used to achieve denitration in the decomposition furnace;

[0019] S4. The mixed gas b transported into the burner through the burner connecting pipeline replaces the primary air and coal supply air after entering the burner to achieve oxygen-enriched combustion.

[0020] The technical solution of the present invention is adopted, and the working principle and beneficial effects are as follows:

[0021] The system of cement kiln oxygen-enriched combustion coupled with combustible gas denitration described in the present invention is structurally arranged such that the gasifier air inlet is connected to the rotary kiln head through a delivery pipeline, the rotary kiln head delivers waste gas into the gasifier through a delivery pipeline, and an oxygen supply pipeline is arranged on the delivery pipeline; in this way, high-purity oxygen is produced by using an oxygen-enriched oxygen-making component, the high-purity oxygen enters the delivery pipeline through the oxygen supply pipeline, and is mixed with the low-temperature waste gas supplied from the rotary kiln head in the delivery pipeline to form high-oxygen-concentration oxygen-enriched air, and the gas mixing process fully utilizes the waste heat of the waste gas from the kiln head to improve the mixing efficiency. After the high-oxygen-concentration oxygen-enriched air is formed, a part of it is sent to the gasifier as a gasifying agent to replace fuel to produce combustible gas, which is intended to increase the calorific value of the product synthesis gas, thereby effectively solving the problem of low calorific value of the synthesis gas in the gasifier, and then it is sent to the decomposition furnace for combustion and heat supply after being dechlorinated by a dechlorinating agent. Another part of the oxygen-enriched air is mixed with the low-temperature exhaust gas or air at the kiln head to form low-concentration oxygen-enriched air, which is sent into the primary air and coal supply air of the rotary kiln head of the rotary kiln to supply the burner, so as to realize oxygen-enriched combustion in the rotary kiln, improve the combustion efficiency in the rotary kiln, and improve the calcination capacity in the kiln. The gasification furnace outlet is connected to the cyclone separator inlet. As an embodiment 1, a cyclone separator is arranged below the preheater, and the preheater discharge port is connected to the cyclone separator feed port; the cyclone separator separates the fly ash carried by the combustible gas entering the cyclone separator from the gasification furnace, and the cement raw material partially decomposed by the preheater enters the cyclone separator, and the chloride ions in the combustible gas are adsorbed and separated. The combustible gas after filtration is sent to the decomposition furnace for combustion assistance, and the fly ash is discharged from the bottom of the cyclone separator. As an embodiment 2, a calcium-based waste delivery component is arranged above the cyclone separator, and the calcium-based waste delivery component is connected to the cyclone separator. The cyclone separator separates the fly ash carried by the combustible gas entering from the gasifier, and the calcium-based waste put into the cyclone separator by the calcium-based waste delivery component absorbs and separates the chloride ions in the combustible gas. The combustible gas filtered in this way is sent to the decomposition furnace for combustion support, and the fly ash is discharged from the bottom of the cyclone separator. The system of cement kiln oxygen-enriched combustion coupled with combustible gas denitrification described in the present invention can not only reliably separate the fly ash carried by the combustible gas entering the cyclone separator from the gasifier, but also realize the adsorption and separation of chloride ions in the combustible gas entering the cyclone separator from the gasifier; at the same time, high-purity oxygen is prepared and mixed with the low-temperature exhaust gas at the kiln head to form high-oxygen-concentration oxygen-enriched air, a part of which is sent to the gasifier as a gasifying agent to replace fuel to produce combustible gas, and the other part of the oxygen-enriched air is mixed with the low-temperature exhaust gas or air at the kiln head to form low-concentration oxygen-enriched air, realizing oxygen-enriched combustion of alternative fuels or coal powder at the kiln head, improving the combustion efficiency of the rotary kiln, and improving the calcination capacity in the kiln. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following is a brief description of the contents and symbols in the drawings of this specification:

[0023] Figure 1 It is a schematic diagram of the structure of the gas mixing components of the system for cement kiln oxygen-enriched combustion coupled with combustible gas denitration according to the present invention;

[0024] Figure 2 This is a schematic structural diagram of a first embodiment of a dechlorination component of a system for cement kiln oxygen-enriched combustion coupled with combustible gas denitration according to the present invention;

[0025] Figure 3 It is a schematic structural diagram of the second embodiment of the dechlorination component of the system for cement kiln oxygen-enriched combustion coupled with combustible gas denitration according to the present invention;

[0026] Figure 4 It is a structural schematic diagram of the system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to the present invention;

[0027] The markings in the attached drawings are: 1. gasification furnace; 2. conveying pipeline; 3. rotary kiln head; 4. cyclone separator; 5. oxygen supply pipeline; 6. preheater; 7. calcium-based waste delivery component; 8. decomposition furnace; 9. burner connecting pipeline; 10. burner; 11. mixed gas a; 12. mixed gas b; 13. oxygen-enriched oxygen production component; 14. gas analyzer; 15. rotary kiln; 16. kiln tail smoke chamber; 17. valve; 18. dechlorination agent; 19. high-purity oxygen. DETAILED DESCRIPTION

[0028] The following is a further detailed description of the specific implementation of the present invention, such as the shape, structure, mutual position and connection relationship between the various components involved, the function and working principle of each part, etc., through the description of the embodiments with reference to the accompanying drawings:

[0029] As attached Figure 1 -Attached Figure 4As shown, the present invention is a system for oxygen-enriched combustion coupled with combustible gas denitrification in a cement kiln, wherein an air inlet of a gasifier 1 is connected to a rotary kiln head 3 through a conveying pipeline 2, an air outlet of the gasifier 1 is connected to an inlet of a cyclone separator 4, and an oxygen supply pipeline 5 is arranged on the conveying pipeline 2; a cyclone separator 4 is arranged below a preheater 6, and a material outlet of the preheater 6 is connected to a material inlet of the cyclone separator 4; or, a calcium-based waste delivery component 7 is arranged above the cyclone separator 4, and the calcium-based waste delivery component 7 is connected to the cyclone separator 4. In the above structure, when the structure is set, the air inlet of the gasifier 1 is connected to the rotary kiln head 3 through the delivery pipeline 2, and the rotary kiln head 3 delivers waste gas into the gasifier 1 through the delivery pipeline 2, and the delivery pipeline 2 is provided with an oxygen supply pipeline 5; in this way, high-purity oxygen is produced by using the oxygen-enriched oxygen-making component 13, and the high-purity oxygen enters the delivery pipeline 2 through the oxygen supply pipeline 5, and is mixed with the low-temperature waste gas supplied by the rotary kiln head 3 in the delivery pipeline 2 to form high-oxygen-concentration oxygen-enriched air. The gas mixing process fully utilizes the waste heat of the rotary kiln head waste gas to improve the mixing efficiency. After the high-oxygen-concentration oxygen-enriched air is formed, a part of it is sent to the gasifier 1 as a gasifying agent to replace the fuel to produce combustible gas. This is to increase the calorific value of the product synthesis gas, thereby effectively solving the problem of low calorific value of the synthesis gas in the gasifier, and then it is sent to the decomposition furnace for combustion and heat supply after being dechlorinated by the dechlorinating agent. Another part of the oxygen-enriched air is mixed with the low-temperature waste gas or air at the kiln head to form low-concentration oxygen-enriched air, which is sent to the primary air and coal supply air of the rotary kiln head 3 of the rotary kiln 15, and supplied to the burner 10, so as to realize the oxygen-enriched combustion of the rotary kiln head 3 to replace the fuel or coal powder, improve the combustion efficiency in the rotary kiln 15, and improve the calcination capacity in the kiln. The gas outlet of the gasifier 1 is connected to the inlet of the cyclone separator 4. As an embodiment 1, a cyclone separator 4 is arranged below the preheater 6, and the discharge port of the preheater 6 is connected to the feed port of the cyclone separator 4; the cyclone separator 4 separates the fly ash carried in the combustible gas entering the cyclone separator from the gasifier 1, and at the same time, the cement raw material partially decomposed by the preheater 6 enters the cyclone separator 4, and the chloride ions in the combustible gas sent from the gasifier 1 to the cyclone separator 4 are adsorbed and separated. The combustible gas after filtering is sent to the decomposition furnace 8 for combustion support, and the fly ash is discharged from the bottom of the cyclone separator 4. As a second embodiment, a calcium-based waste delivery component 7 is provided above the cyclone separator 4, and the calcium-based waste delivery component 7 is connected to the cyclone separator 4. The cyclone separator 4 separates the fly ash carried in the combustible gas entering the cyclone separator 4 from the gasifier 1, and at the same time, the calcium-based waste delivered by the calcium-based waste delivery component 7 into the cyclone separator 4 adsorbs and separates the chloride ions in the combustible gas generated by the gasifier 1, and the combustible gas filtered is sent to the decomposition furnace 8 for combustion support, and the fly ash is discharged from the bottom of the cyclone separator 4. In the technology of the present invention, the dechlorination agent is mainly added to the calcium-based waste at the outlet of the gasifier, and red mud, white mud, carbide slag, or cement raw meal from the preheater 6 are selected. Not all wastes can achieve the function, and the selection of waste materials is very important.The system for oxygen-enriched combustion coupled with combustible gas denitrification in a cement kiln described in the present invention has a simple structure and can reliably separate fly ash carried in the combustible gas entering the cyclone separator from the gasifier, and can also realize adsorption separation of chloride ions in the combustible gas entering the cyclone separator from the gasifier; at the same time, high-purity oxygen is prepared and mixed with the low-temperature exhaust gas at the kiln head to form oxygen-enriched air with high oxygen concentration, and the waste heat at the kiln head of the rotary kiln is fully utilized. A part of the oxygen-enriched air is sent to the gasifier as a gasifying agent to replace fuel to produce combustible gas, and the other part of the oxygen-enriched air is mixed with the low-temperature exhaust gas or air at the kiln head to form low-concentration oxygen-enriched air, which enters the burner of the rotary kiln to realize oxygen-enriched combustion of alternative fuels or pulverized coal at the kiln head, thereby improving the combustion efficiency of the rotary kiln and improving the calcination capacity in the kiln.

[0030] The discharge port of the preheater 6 is connected to the feed port of the cyclone separator 4, and the preheater 6 is connected to the decomposition furnace 8. In the above structure, as an improvement of the first embodiment, the preheater 6 is connected to the decomposition furnace 8, and the filtered combustible gas is sent to the decomposition furnace 8 for combustion support. Alternatively, the calcium-based waste delivery component 7 is connected to the cyclone separator 4, and the cyclone separator 4 is connected to the decomposition furnace 8. When the calcium-based waste delivery component 7 is connected to the cyclone separator 4, the cyclone separator 4 is connected to the decomposition furnace 8. In the above structure, as an improvement of the second embodiment, the cyclone separator 4 is connected to the decomposition furnace 8, and the combustible gas separated and filtered by the cyclone separator 4 is sent to the decomposition furnace 8 for combustion support.

[0031] When the discharge port of the preheater 6 is connected to the feed port of the cyclone separator 4, the cyclone separator 4 is configured to be capable of separating the fly ash carried by the combustible gas entering the cyclone separator 4 from the gasifier 1, and the cement raw meal partially decomposed by the preheater 6 is configured to be capable of entering the cyclone separator 4, and the chloride ions in the combustible gas entering the cyclone separator 4 from the gasifier 1 are adsorbed and separated. The above structure, as an improvement of the first embodiment, forms a dechlorination component, which enables the cement raw meal partially decomposed by the preheater 6 to be introduced into the cyclone separator 4 to dechlorinate the combustible gas.

[0032] When the calcium-based waste delivery component 7 is connected to the cyclone separator 4, the cyclone separator 4 is configured to be capable of separating fly ash carried by the combustible gas entering the cyclone separator 4 from the gasifier 1, and the calcium-based waste delivered by the calcium-based waste delivery component 7 to the cyclone separator 4 is configured to be capable of adsorbing and separating chloride ions in the combustible gas entering the cyclone separator 4 from the gasifier 1. The above structure, as an improvement of the second embodiment, forms a dechlorination component, and the calcium-based waste delivery component 7 delivers calcium-based waste to the cyclone separator for dechlorination.

[0033] When the discharge port of the preheater 6 is connected to the feed port of the cyclone separator 4, the discharge port of the preheater 6 is connected to the feed port of the cyclone separator 4 through a pipeline, and a valve 17 is provided on the pipeline. When the discharge port of the preheater 6 is connected to the feed port of the cyclone separator 4, the CaO content in the cement raw material delivered by the preheater 6 to the cyclone separator 4 is not less than 63%. In the above structure, the valve 17 can control the unloading speed of the preheater 6. The unloading speed needs to be controlled for different types of production lines. For example, for a 5000t / d clinker production line, the unloading speed of the cement raw material is controlled to be less than 1 ton / hour, and for the cement raw material supplied by the preheater 6, the CaO content of the decomposed cement raw material supplied is controlled to be not less than 63%.

[0034] When the calcium-based waste delivery component 7 is connected to the cyclone separator 4, the calcium-based waste in the calcium-based waste delivery component 7 is red mud or white mud or carbide slag or cement raw material. The above structure dechlorinates the combustible gas by supplying calcium-based waste 7 into the cyclone separator 4. The feeding speed of calcium-based waste needs to be controlled for different types of production lines. For example, for a 5000t / d clinker production line, the feeding speed of calcium-based waste is less than 1 ton / hour; the particle size of the calcium-based waste is less than 100μm. The speed and particle size of production lines of different types can be adjusted.

[0035] The delivery pipeline 2 is connected to the burner 10 of the rotary kiln 15 through the burner connecting pipeline 9. The mixed gas in the delivery pipeline 5 close to the gasifier 1 is the mixed gas a11, and the mixed gas in the burner connecting pipeline 9 close to the burner 10 is the mixed gas b12. The oxygen concentration of the mixed gas a11 is 40-45%; the oxygen concentration of the mixed gas b12 is 30-40%. This is to increase the calorific value of the product synthesis gas and effectively solve the problem of low calorific value of the synthesis gas in the gasifier.

[0036] The mixed gas a is further mixed with the kiln exhaust gas to form a mixed gas b, which is then introduced into the burner to replace the primary air and coal supply air to achieve oxygen-enriched combustion. The realization of oxygen-enriched combustion helps to improve the temperature field in the kiln, thereby improving the quality and output of clinker and reducing coal consumption. In the above structure, the mixed gas a is used to supply the gasifier, and the mixed gas b is used to supply the burner of the rotary kiln 15.

[0037] When the gasification furnace 1 air inlet is connected to the rotary kiln head 3 through the delivery pipeline 2, the oxygen injection pressure of the oxygen supply pipeline 5 is 20kpa-40kpa; the pressure of the kiln head exhaust gas is 10kpa-20kpa; the purity of oxygen is 65%-99.999%. The above structure controls the oxygen injection pressure, the pressure of the kiln head exhaust gas, and the purity of oxygen, thereby improving the quality of oxygen-enriched oxygen.

[0038] The present invention also relates to a control method for a system of cement kiln oxygen-enriched combustion coupled with combustible gas denitration, characterized in that the control steps of the control method for the system of cement kiln oxygen-enriched combustion coupled with combustible gas denitration are as follows:

[0039] S1. The mixed gas in the conveying pipeline 5 near the gasifier 1 is the mixed gas a11, which is conveyed into the gasifier 1, and the mixed gas in the burner connecting pipeline 9 near the burner 10 is the mixed gas b12, which is conveyed into the burner 10, and the oxygen concentration of the mixed gas a11 is 40-45%; the oxygen concentration of the mixed gas b12 is 30-40%; S2. When the discharge port of the preheater 6 is connected to the feed port of the cyclone separator 4, the cyclone separator 4 separates the fly ash carried by the combustible gas entering the cyclone separator 4 from the gasifier 1, and the cement raw meal partially decomposed by the preheater 6 enters the cyclone separator 4, and the chloride ions in the combustible gas generated by the gasifier 1 are adsorbed and separated, and the fly ash is discharged from the cyclone separator 4; or, the calcium-based waste delivery component 7 is connected to the cyclone The separator 4 is used for separating the fly ash carrying gas in the gasifier 1 by the cyclone separator 4, and the calcium-based waste introduced into the cyclone separator 4 by the calcium-based waste introducing component 7 absorbs and separates the chloride ions in the combustible gas entering the cyclone separator 4 from the gasifier 1, and the fly ash is discharged from the cyclone separator 4; S3. The dechlorinated combustible gas is sent to the conical reduction zone of the decomposition furnace 8, and the reducing gas in the combustible gas is used to realize denitrification in the decomposition furnace 8. The denitrification treatment can reduce the emission of nitrogen oxides (NOx), reduce air pollution and the formation of acid rain, help improve air quality, and reliably protect the environment; S4. The mixed gas b12 transported into the burner 10 by the burner connecting pipeline 9 replaces the primary air and the coal supply air after entering the burner 10 to realize oxygen-enriched combustion.

[0040] In the system of oxygen-enriched combustion coupled with combustible gas denitration in the cement kiln of the present invention, the high-purity oxygen produced by the oxygen-enriched oxygen-producing component 13, the mixed gas a11, and the mixed gas b12 supplying the gasifier 1 and the burner 10 are respectively provided with shut-off valves, and the oxygen content entering the gasifier 1 and the rotary kiln 15 is controlled by the valves. The kiln head exhaust gas is the gas discharged from the kiln head chimney after the grate cooler cools the clinker, and is used to mix with the high-purity oxygen produced by the oxygen-enriched oxygen-producing component. The gas mixing component is used to mix the high-purity oxygen produced by the oxygen-enriched oxygen-producing component with the kiln head exhaust gas. A device for monitoring the oxygen content is installed inside, and the oxygen concentration in the mixed gas is controlled by a valve. The outlet section of the gasifier 1 is provided with a gas analyzer 14 to detect chloride ions of the combustible gas at the outlet of the gasifier 1 to detect whether it meets the standard. If it meets the standard, dechlorination is not required. If it does not meet the standard, the chloride ion content in the gasifier 1 is controlled by adding a dechlorinating agent into the gasifier 1, and the chloride ion content of the combustible gas entering the decomposition furnace after passing through the cyclone separator is controlled, and the chloride ion index in the decomposition furnace is indirectly controlled. In embodiment 2, the composition of the dechlorinating agent includes red mud, white mud, carbide slag or cement raw material, and the problem of crusting in the furnace is alleviated by actual proportioning. The outlet of the gasifier is connected to the reduction zone of the decomposition furnace, and the reducing components such as CO and methane in the product are utilized to enhance the reduction effect in the decomposition furnace. The gasifier can be in the form of a fixed bed, a bubbling bed, a fluidized bed, etc.

[0041] The system of oxygen-enriched combustion coupled with combustible gas denitrification in the cement kiln described in the present invention uses a vacuum pressure swing adsorption method or a cryogenic air separation method as the method of oxygen-enriched oxygen production components. The device is in front of the primary air at the kiln head 3 of the rotary kiln and the gasifier 1, and two oxygen-enriched atmospheres of different concentrations are produced through two stages of oxygen mixing processes and sent to the gasifier 1 and the rotary kiln 15 respectively. Oxygen-enriched air is used as a gasifying agent in the gasifier 1 to increase the calorific value of the product synthesis gas and solve the problem of low calorific value of the synthesis gas in the gasifier 1. In the rotary kiln 15, the kiln head primary air and coal supply air are replaced to realize oxygen-enriched combustion in the kiln, improve the temperature field in the kiln, improve the quality and output of clinker, and reduce coal consumption. The decomposition furnace is located at the upper part of the rotary kiln tail smoke chamber, and the gasification furnace 1 is connected to the decomposition furnace. The synthesis gas generated in the gasification furnace enters the decomposition furnace and is burned at high temperature to provide heat for the decomposition furnace; the tail smoke chamber is the tail of the rotary kiln, connecting the rotary kiln 15 and the decomposition furnace. The material of the decomposition furnace enters the rotary kiln through the tail smoke chamber, and the gas of the rotary kiln enters the decomposition furnace through the smoke chamber; the gasification furnace is a pretreatment device for alternative fuels, which can convert alternative fuels (such as RDF, biomass, etc.) into high calorific value synthesis gas and send it to the decomposition furnace. In this way, the problem of excessive harmful elements in alternative fuels is solved, the heat replacement rate of alternative fuels is further increased, and coal consumption is reduced.

[0042] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A cement kiln oxygen-enriched combustion coupled combustible gas denitrification system, characterized in that: The gasification furnace (1) has an air inlet connected to a rotary kiln head (3) through a conveying pipeline (2), and the gasification furnace (1) has an air outlet connected to an inlet of a cyclone separator (4). An oxygen supply pipeline (5) is arranged on the conveying pipeline (2); a cyclone separator (4) is arranged below the preheater (6), and a discharge port of the preheater (6) is connected to a feed port of the cyclone separator (4); or a calcium-based waste delivery component (7) is arranged above the cyclone separator (4), and the calcium-based waste delivery component (7) is connected to the cyclone separator (4).

2. The system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to claim 1 is characterized in that: The discharge port of the preheater (6) is connected to the feed port of the cyclone separator (4), and the preheater (6) is connected to the decomposition furnace (8); or, the calcium-based waste delivery component (7) is connected to the cyclone separator (4), and the cyclone separator (4) is connected to the decomposition furnace (8).

3. The system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to claim 1 or 2, characterized in that: When the discharge port of the preheater (6) is connected to the feed port of the cyclone separator (4), the cyclone separator (4) is configured to be a structure capable of separating fly ash carried by the combustible gas entering the cyclone separator (4) from the gasifier (1), and the cement raw meal partially decomposed by the preheater (6) is configured to be a structure capable of entering the cyclone separator (4) and adsorbing and separating chloride ions in the combustible gas entering the cyclone separator (4) from the gasifier (1).

4. The system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to claim 1 or 2, characterized in that: When the calcium-based waste delivery component (7) is connected to the cyclone separator (4), the cyclone separator (4) is configured to have a structure capable of separating fly ash carried by the combustible gas entering the cyclone separator (4) from the gasifier (1), and the calcium-based waste delivered to the cyclone separator (4) by the calcium-based waste delivery component (7) is configured to have a structure capable of adsorbing and separating chloride ions in the combustible gas entering the cyclone separator (4) from the gasifier (1).

5. The system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to claim 1 or 2, characterized in that: When the discharge port of the preheater (6) is connected to the feed port of the cyclone separator (4), the discharge port of the preheater (6) is connected to the feed port of the cyclone separator (4) through a pipeline, and a valve (17) is arranged on the pipeline.

6. The system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to claim 1 or 2, characterized in that: When the calcium-based waste delivery component (7) is connected to the cyclone separator (4), the calcium-based waste in the calcium-based waste delivery component (7) is red mud or white mud or carbide slag or cement raw material.

7. The system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to claim 1 or 2, characterized in that: When the discharge port of the preheater (6) is connected to the feed port of the cyclone separator (4), the CaO content in the cement raw material transported from the preheater (6) to the cyclone separator (4) is not less than 63%.

8. The system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to claim 1 or 2, characterized in that: The delivery pipeline (2) is simultaneously connected to the burner (10) at the kiln head of the rotary kiln (15) through the burner connecting pipeline (9); the mixed gas in the delivery pipeline (5) close to the gasifier (1) is mixed gas a (11); the mixed gas in the burner connecting pipeline (9) close to the burner (10) is mixed gas b (12); the oxygen concentration of the mixed gas a (11) is 40-45%; the oxygen concentration of the mixed gas b (12) is 30-40%.

9. The system for cement kiln oxygen-enriched combustion coupled with combustible gas denitrification according to claim 1 or 2, characterized in that: When the gasification furnace (1) air inlet is connected to the rotary kiln head (3) through the delivery pipeline (2), the oxygen injection pressure of the oxygen supply pipeline (5) is 20kpa-40kpa; the pressure of the kiln head exhaust gas is 10kpa-20kpa; the purity of oxygen is 65%-99.999%.

10. A control method for a cement kiln oxygen-enriched combustion coupled with combustible gas denitrification system, characterized in that: The control steps of the control method of the cement kiln oxygen-enriched combustion coupled combustible gas denitrification system are as follows: S1. The mixed gas in the delivery pipeline (5) near the gasifier (1) is mixed gas a (11), which is delivered to the gasifier (1), and the mixed gas in the burner connecting pipeline (9) near the burner (10) is mixed gas b (12), which is delivered to the burner (10), the oxygen concentration of the mixed gas a (11) is 40-45%; the oxygen concentration of the mixed gas b (12) is 30-40%; S2. When the discharge port of the preheater (6) is connected to the feed port of the cyclone separator (4), the cyclone separator (4) separates the fly ash carried by the combustible gas entering the cyclone separator (4) from the gasifier (1), and the cement raw meal partially decomposed by the preheater (6) enters the cyclone separator (4), and the chloride ions in the combustible gas generated by the gasifier (1) are adsorbed and separated, and the fly ash is discharged from the cyclone separator (4); or, when the calcium-based waste delivery component (7) is connected to the cyclone separator (4), the cyclone separator (4) separates the fly ash carried by the gas in the gasifier (1), and the calcium-based waste delivered to the cyclone separator (4) by the calcium-based waste delivery component (7) adsorbs and separates the chloride ions in the combustible gas entering the cyclone separator (4) from the gasifier (1), and the fly ash is discharged from the cyclone separator (4); S3. The combustible gas is sent to the cone reduction zone of the decomposition furnace (8), and the reducing gas in the combustible gas is used to achieve denitration in the decomposition furnace (8); S4. The mixed gas b (12) transported by the burner connecting pipeline (9) into the burner (10) replaces the primary air and the coal supply air after entering the burner (10), thereby achieving oxygen-enriched combustion.

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