WO2022236593A1 - 一种全氧燃烧生产水泥熟料的系统及方法 - Google Patents

一种全氧燃烧生产水泥熟料的系统及方法 Download PDF

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Publication number
WO2022236593A1
WO2022236593A1 PCT/CN2021/092821 CN2021092821W WO2022236593A1 WO 2022236593 A1 WO2022236593 A1 WO 2022236593A1 CN 2021092821 W CN2021092821 W CN 2021092821W WO 2022236593 A1 WO2022236593 A1 WO 2022236593A1
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Prior art keywords
cooling
flue gas
gas
rotary kiln
enters
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PCT/CN2021/092821
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English (en)
French (fr)
Inventor
何小龙
彭学平
陈昌华
代中元
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天津水泥工业设计研究院有限公司
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Priority to PCT/CN2021/092821 priority Critical patent/WO2022236593A1/zh
Priority to CN202180021197.5A priority patent/CN115867515A/zh
Publication of WO2022236593A1 publication Critical patent/WO2022236593A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B7/00—Hydraulic cements
    • C04B7/36—Manufacture of hydraulic cements in general
    • C04B7/43—Heat treatment, e.g. precalcining, burning, melting; Cooling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D13/00—Apparatus for preheating charges; Arrangements for preheating charges

Definitions

  • the invention belongs to the technical field of cement technology, and in particular relates to a system and method for producing cement clinker by oxy-fuel combustion.
  • Carbon dioxide in cement kiln exhaust gas mainly comes from the following two aspects:
  • the carbon dioxide generated in the flue gas of fuel combustion accounts for about 40%.
  • the carbon dioxide produced by the decomposition of carbonate in raw materials accounts for about 60%.
  • Oxygen combustion refers to the use of industrial oxygen instead of air to burn fuel, which can make the fuel burn more completely. Compared with air combustion, oxyfuel combustion has the following advantages:
  • Oxy-fuel combustion technology can save fuel, reduce NOx emissions, and meet the requirements of purifying the environment.
  • cement kilns mainly use oxy-fuel combustion technology in calciners and rotary kilns.
  • the original cooler is divided into the first cooling zone and the second cooling zone.
  • the first cooling zone is fed with the mixed gas of pure oxygen and carbon dioxide flue gas to exchange heat with the clinker, and part of the mixed gas after heat exchange enters the rotary kiln , and the other part enters the calciner for full-oxygen combustion of the fuel in the rotary kiln and calciner.
  • the second cooling zone is fed with conventional air to exchange heat with clinker, and the air after heat exchange is used for waste heat utilization or discharge.
  • O 2 concentration in the O 2 /CO 2 mixed gas fed into the rotary kiln is not easy to adjust, so it is impossible to control the flame temperature of the rotary kiln's full-oxygen combustion, because the O 2 /CO 2 mixed gas in the first-stage cooling zone It is difficult to flexibly adjust the O2 concentration in the actual production and operation process.
  • the reason is: O 2 /CO 2 mixed gas passes through the first cooling zone of the cooler and then enters the rotary kiln for fuel combustion. Since the equipment structure and grate bed area of the cooler are fixed during operation, the first cooling zone The cooling air volume corresponding to the area of the grate bed is relatively fixed.
  • the circulating flue gas volume is increased, the O 2 concentration in the O 2 /CO 2 mixture will be reduced, but the cooling air volume will increase, which will lead to an increase in the resistance of the grate bed; Reducing the circulating flue gas volume can increase the O 2 concentration in the O 2 /CO 2 mixture, but it will reduce the cooling air volume, which will lead to insufficient cooling of the clinker in the first cooling zone.
  • the temperature of the combustion flame in the rotary kiln is too high, and the lining is easily damaged. Especially when the thickness and direction of the flame are unstable during the combustion process, the high-temperature flame is easy to contact the lining of the rotary kiln, which will damage the lining of the rotary kiln.
  • the present invention provides a system and method for the production of cement clinker by oxy-fuel combustion, which solves the problem of introducing O 2 /CO 2 mixed gas into the rotary kiln existing in the oxy-fuel combustion technology of the existing cement kiln.
  • the concentration of O2 in the medium is not easy to adjust, so the flame temperature of the oxy-fuel combustion in the rotary kiln cannot be controlled, and the combustion flame temperature in the rotary kiln is too high, and the inner lining is easily damaged.
  • the present invention realizes through following technical scheme:
  • a system for producing cement clinker by oxy-fuel combustion includes a preheater, a calciner, a smoke chamber, a rotary kiln and a cooler, the rotary kiln communicates with the cooler, and the rotary kiln is provided with Combustor; characterized in that, the cooling machine includes a first cooling zone and a second cooling zone, and the first cooling zone includes a first cooling subregion and a second cooling subregion;
  • the inlet of the first cooling zone is fed with a mixture of high-concentration pure oxygen and carbon dioxide flue gas
  • the outlet of the first cooling zone is connected with the air inlet of the rotary kiln
  • the outlet of the first cooling zone discharges the first cooling gas.
  • Gas, the first cooling gas enters the air inlet of the rotary kiln as secondary air, and the first cooling gas is a mixture of high-concentration pure oxygen and carbon dioxide flue gas after heat exchange;
  • the inlet of the second cooling subregion is fed with carbon dioxide flue gas
  • the outlet of the second cooling subregion communicates with the air inlet of the rotary kiln through the first pipe
  • the outlet of the second cooling subregion discharges the second cooling gas to control the first
  • the secondary cooling gas enters the air inlet of the rotary kiln as the quaternary air
  • the second cooling gas is carbon dioxide flue gas after heat exchange
  • the inlet of the second cooling zone is fed with air, and the outlet of the second cooling zone is discharged with third cooling gas, the third cooling gas is air after heat exchange.
  • the air inlet of the rotary kiln is provided with an air distribution hood
  • the first cooling gas entering the rotary kiln is introduced into the central position inside the air distribution hood, so that the first cooling gas is distributed in the central area of the rotary kiln;
  • the second cooling gas entering the rotary kiln is introduced to the periphery of the air distribution hood, so that the second cooling gas is distributed in the peripheral area inside the rotary kiln.
  • the burner is arranged at the center of the rotary kiln.
  • the second cooling zone is located between the first cooling zone and the second cooling zone.
  • the cooler adopts a grate cooler, and a roller crusher is arranged in the middle of the grate cooler, and the cooler is divided into a first cooling zone and a second cooling zone.
  • a partition wall is set in the middle of the first cooling zone to divide the first cooling zone into a first cooling zone and a second cooling zone.
  • outlet of the second cooling subregion is also communicated with the air inlet of the preheater through a second pipe, and part of the second cooling gas discharged from the outlet of the second cooling subregion is used to preheat the raw material of the preheater. hot.
  • outlet of the first cooling zone is also communicated with the air inlet of the calciner through the tertiary air duct;
  • Part of the first cooling gas discharged from the outlet of the first cooling zone enters the calciner as tertiary air for fuel combustion.
  • the air outlet of the preheater is connected to the first fan through the third pipe, the flue gas at the air outlet of the first fan is divided into two paths, the first flue gas enters the exhaust gas treatment system through the fourth pipe, and the second flue gas enters the waste gas treatment system through the fourth pipe.
  • the second flue gas enters the fifth pipe with the second fan, and the flue gas at the outlet of the fifth pipe is mixed with high-concentration pure oxygen as circulating flue gas and enters the inlet of the first cooling zone.
  • the air outlet of the preheater is connected to the first fan through the third pipe, the flue gas at the air outlet of the first fan is divided into two paths, the first flue gas enters the exhaust gas treatment system through the fourth pipe, and the second flue gas enters the waste gas treatment system through the fourth pipe.
  • the flue gas from the second channel enters the fifth pipeline where the second blower is installed, and the flue gas from the outlet of the fifth pipeline enters the inlet of the second cooling zone as circulating flue gas.
  • the air outlet of the preheater is connected to the first fan through the third pipe, the flue gas at the air outlet of the first fan is divided into two paths, the first flue gas enters the exhaust gas treatment system through the fourth pipe, and the second flue gas enters the waste gas treatment system through the fourth pipe.
  • the second flue gas enters the fifth pipe with the second blower, the flue gas at the outlet of the fifth pipe is divided into two paths as circulating flue gas, and the first circulating flue gas enters the sixth pipe and mixes with high-concentration pure oxygen to form the mixed gas.
  • the flue gas enters the inlet of the first cooling zone, and the second circulating flue gas enters the inlet of the second cooling zone through the seventh pipe.
  • a heat exchanger is arranged on the third pipeline.
  • the fifth pipeline is provided with a dust collector near the air inlet of the second fan.
  • a valve is set on the first pipeline.
  • Adopt the method for above-mentioned system production cement clinker comprise the steps:
  • the raw meal is fed into the preheater, and the raw meal is separated from the flue gas by heat exchange in the preheater to obtain the preheated raw meal;
  • the preheated raw meal enters the calciner, and the combustion of the fuel in the calciner releases a large amount of heat for the decomposition of the raw meal to obtain hot raw meal;
  • the hot raw material enters the rotary kiln through the smoke chamber, and is calcined in the rotary kiln to form cement clinker.
  • the cement clinker enters the cooler from the outlet of the rotary kiln.
  • the mixed gas of high-concentration pure oxygen and carbon dioxide flue gas passed into the first cooling zone is used to cool the cement clinker for the first time to obtain the first cooling gas and the first cooled cement clinker;
  • the first cooling gas enters the air inlet of the rotary kiln as secondary air, and the first cooling gas is a mixture of high-concentration pure oxygen and carbon dioxide flue gas after heat exchange;
  • the first cooled cement clinker falls into the second cooling subregion, and the carbon dioxide flue gas passed into the second cooling subregion performs second cooling on the first cooled cement clinker to obtain the second cooled gas and the second cooled cement clinker;
  • the second cooling gas is carbon dioxide flue gas after heat exchange
  • the second cooling cement clinker enters the second cooling zone, and the air passed into the second cooling zone cools the second cooling cement clinker for the third time to obtain the finished cement clinker and the third cooling gas. hot air;
  • the kiln gas entering the calciner is mixed with the flue gas formed by fuel combustion and raw meal decomposition in the calciner to obtain a mixed flue gas product, which enters the preheater through the calciner and exchanges heat with the raw meal in the preheater Separation becomes low-temperature flue gas, and the low-temperature flue gas is discharged from the top air outlet of the preheater.
  • first cooling gas entering the rotary kiln is distributed in the central area of the rotary kiln
  • second cooling gas entering the rotary kiln is distributed in the peripheral area inside the rotary kiln.
  • the low-temperature flue gas discharged from the top air outlet of the preheater includes the following three processing routes:
  • the discharged low-temperature flue gas enters the first fan, and the flue gas at the air outlet of the first fan is divided into two paths.
  • the first flue gas enters the exhaust gas treatment system, and the second flue gas passes through the second fan as circulating flue gas and high Concentrated pure oxygen is mixed to become the inlet of the mixed gas entering the first cooling zone;
  • the exhausted low-temperature flue gas enters the first fan, and the flue gas at the air outlet of the first fan is divided into two paths.
  • the first flue gas enters the waste gas treatment system, and the second flue gas passes through the second fan and enters the second flue gas as circulating flue gas.
  • the discharged low-temperature flue gas enters the first fan, and the flue gas at the air outlet of the first fan is divided into two paths. Two paths, the first path of circulating flue gas is mixed with high-concentration pure oxygen to form the inlet of the first cooling zone, and the second path of circulating flue gas enters the inlet of the second cooling zone.
  • the first cooling gas also enters the calciner as tertiary air for fuel combustion.
  • the second cooling gas also enters the air inlet of the preheater, so as to preheat the raw material of the preheater.
  • the exhausted low-temperature flue gas before the exhausted low-temperature flue gas enters the first fan, it first enters the heat exchanger for heat exchange and utilization.
  • the second flue gas before the second flue gas enters the second fan, it first enters the dust collector for dust removal treatment.
  • the cooler includes a first cooling zone and a second cooling zone
  • the first cooling zone includes a first cooling subregion and a second cooling subregion
  • the inlet of the first cooling subregion leads to A mixture of high-concentration pure oxygen and carbon dioxide flue gas
  • the outlet of the first cooling zone is connected to the air inlet of the rotary kiln
  • the first cooling gas that is, high-concentration pure oxygen and carbon dioxide after heat exchange
  • the mixed gas of the flue gas enters the air inlet of the rotary kiln as the secondary air
  • the inlet of the second cooling zone is fed with carbon dioxide flue gas
  • the outlet of the second cooling zone is connected with the air inlet of the rotary kiln through the first pipe to control the second
  • the second cooling gas that is, the carbon dioxide flue gas after heat exchange
  • An air distribution hood is installed at the air inlet of the rotary kiln, and the first cooling gas entering the rotary kiln is introduced into the center of the inner side of the air distribution hood, so that the first cooling gas is distributed in the central area of the rotary kiln, and the second cooling gas entering the rotary kiln is introduced into the air distribution hood.
  • the periphery of the air hood makes the second cooling gas distributed in the peripheral area inside the rotary kiln, thereby forming a graded oxygen concentration distribution environment in the rotary kiln with low oxygen content in the periphery and high oxygen content in the central area, so as to realize the fuel flow in the central area of the rotary kiln.
  • the peripheral oxygen concentration of the rotary kiln is low, forming a low-oxygen concentration inert gas protective layer, which hinders the diffusion of the high-temperature flame in the rotary kiln to the periphery, prevents the high-temperature flame from contacting the wall of the rotary kiln, and prevents the lining of the rotary kiln from Burned by high-temperature flames, it improves the safety of equipment under full-oxygen combustion in cement kilns.
  • the burner is inserted into the central position of the rotary kiln, so as to ensure that the fuel is sprayed to the central area of the rotary kiln through the burner, and burns rapidly in the central area to form a high-temperature flame, further preventing the high-temperature flame from contacting the wall of the rotary kiln.
  • the outlet of the second cooling zone is also connected to the air inlet of the preheater through the second pipe, so that the high-temperature heat of the carbon dioxide flue gas after cooling the cement clinker is used for heat exchange of raw materials in the preheater, thereby reducing the cement production system. heat energy consumption.
  • Fig. 1 is the structural representation of the system of producing cement clinker by oxyfuel combustion of the present invention
  • Fig. 2 is a flow chart of a method for producing cement clinker by oxy-fuel combustion.
  • Fig. 3 is a partial schematic view of the rotary kiln of the present invention.
  • Fig. 4 is the side view of Fig. 3;
  • connection should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention based on specific situations.
  • FIG. 1 it is a schematic structural diagram of the system for producing cement clinker by oxy-fuel combustion in this embodiment.
  • the dotted line with arrows in the figure is the airflow direction, and the solid line with arrows is the direction of material flow.
  • the oxy-fuel combustion production of cement clinker The system includes smoke chamber 1, rotary kiln 2, cooler 3 and raw material preheating and pre-decomposition system.
  • the raw material preheating and pre-decomposition system is connected with the smoke chamber 1, the burner 201 is set on the rotary kiln 2, and the fuel F is passed into the burner 201, the tail of the rotary kiln 2 is connected with the smoke chamber 1, and the head of the rotary kiln 2 is connected with the cooling chamber.
  • Machine 3 is connected.
  • the raw meal preheating and pre-decomposition system includes a decomposition furnace 4 and a preheater 5.
  • the preheater 5 is preferably a cyclone preheater.
  • the preheater 5 shown in the figure is a cyclone preheater, and the cyclone preheater only uses 1
  • the column number of cyclone preheaters it should be noted that the number of columns of cyclone preheaters in the figure is only for illustration, and those skilled in the art can set it according to actual needs.
  • a burner is arranged on the calciner 4, and the fuel F is passed into the burner.
  • the raw material inlet is provided on the side wall of the calciner 4, and an air outlet pipe 401 is arranged on the top of the calciner 4. It should be noted that the air outlet pipe 401 can also be provided On the side of calciner 4.
  • the air inlet at the bottom of the above-mentioned preheater 5 is connected to the outlet pipe 401 of the calciner 4, the air outlet at the top of the preheater 5 discharges low-temperature flue gas, and the top inlet of the preheater 5 is used for feeding raw material R,
  • the discharge port at the bottom of the preheater 5 is connected to the smoke chamber 1.
  • the cyclone preheater shown in the figure includes a first cyclone separator 501, a second cyclone separator 502, a third cyclone separator 503,
  • a fourth cyclone separator 504 and the fifth cyclone separator 505 it should be noted that the number of cyclone separators in the figure is only for illustration, and those skilled in the art can set them as required.
  • the top of the first cyclone separator 501 is provided with an air outlet, and the air outlet discharges low-temperature flue gas.
  • the top side of the first cyclone separator 501 is connected with the first air inlet pipe 601.
  • the feed port is used for feeding raw material, and the bottom end of the first cyclone separator 501 communicates with the second air inlet pipe 602 .
  • the top of the second cyclone separator 502 communicates with the first air inlet pipe 601, the top side of the second cyclone separator 502 communicates with the second air inlet pipe 602, and the bottom of the second cyclone separator 502 communicates with the third air inlet pipe. 603 connected.
  • the top of the third cyclone separator 503 communicates with the second air inlet pipe 602, the top side of the third cyclone separator 503 communicates with the third air inlet pipe 603, and the bottom end of the third cyclone separator 503 communicates with the fourth air inlet pipe. 604 connected.
  • the top of the fourth cyclone separator 504 is communicated with the third air inlet pipe 603, the top side of the fourth cyclone separator 504 is communicated with the fourth air inlet pipe 604, and the bottom end of the fourth cyclone separator 504 is connected with the raw material of the calciner 4.
  • the material inlet is connected.
  • the top of the fifth cyclone separator 505 is communicated with the fourth air inlet pipe 604, and the top side of the fifth cyclone separator 505 is provided with an air inlet, and the air inlet is communicated with the air outlet pipe 401 of the calciner 4 through the communication pipe 7, and the fifth cyclone A discharge port is provided at the bottom of the separator 505 , and the discharge port communicates with the smoke chamber 1 .
  • the above-mentioned cooler 3 adopts a grate cooler, and a roller crusher 11 is arranged in the middle of the grate cooler, and the cooler 3 is divided into a first cooling zone 301 and a second cooling zone 302, and a partition is set in the middle of the first cooling zone 301.
  • the wall 12 divides the first cooling zone 301 into a first cooling zone 3011 and a second cooling zone 3012 , and the second cooling zone 3012 is arranged between the first cooling zone 3011 and the second cooling zone 302 .
  • the inlet of the first cooling zone 3011 is fed with a mixture of high-concentration pure oxygen A and carbon dioxide flue gas, the oxygen concentration in the mixture is 50-98%, and the inlet of the second cooling zone 3012 is fed with carbon dioxide
  • the oxygen concentration in B is lower than 10%
  • the inlet of the second cooling zone 302 is passed into air C
  • the output source of the air can be a blower fan, and pure oxygen can be produced by an oxygen system or can be purchased, and the preferred range of pure oxygen purity is 85 -98%.
  • the cooling machine 3 adopts the above-mentioned zone setting, which can block the air blowing between the first cooling zone 3011 and the second cooling zone 3012, thereby avoiding the reduction of the carbon dioxide concentration entering the first cooling zone 3011, thereby increasing the carbon dioxide of the cement production system. enrichment effect.
  • the outlet of the first cooling zone 3011 discharges the first cooling gas.
  • the first cooling gas is a mixture of high-concentration pure oxygen and carbon dioxide flue gas after heat exchange.
  • the first cooling gas is divided into two paths. The first cooling gas g1 of the first path directly enters the rotary kiln 2 as secondary air for fuel combustion, and the first cooling gas g2 of the second path enters the calciner 4 as tertiary air through the tertiary air pipe 8 for fuel combustion.
  • the outlet of the second cooling zone 3012 discharges the second cooling gas.
  • the second cooling gas is high-temperature carbon dioxide flue gas after heat exchange.
  • the second cooling gas is divided into two paths, and the second cooling gas g31 of the first path passes through as the fourth air.
  • the first pipeline 901 enters the air inlet of the rotary kiln, and a valve 10 is set on the first pipeline 901, and the gas volume of the second cooling gas entering the rotary kiln is adjusted through the valve 10 , thereby adjusting the O concentration in the mixed gas in the rotary kiln, Then control the flame temperature of the rotary kiln full oxygen combustion.
  • the second cooling gas g32 of the second path enters the air inlet of the preheater 5 through the second pipeline 902, that is, enters the air inlet of the fifth cyclone separator 505, so that the high-temperature heat of the carbon dioxide flue gas after cooling the cement clinker is used
  • the raw material heat exchange in the preheater thereby reducing the thermal energy consumption of the cement production system.
  • the outlet of the second cooling zone 302 discharges the third cooling gas g4, the third cooling gas g4 is air after heat exchange, the temperature of the third cooling gas g4 is 200-300°C, it is used for drying heat source of the raw material and fuel grinding system, In this way, the heat source generated by the cement production system can be further fully utilized, and the cement clinker finished product K can be obtained after the cement clinker is cooled in the second cooling zone 302 .
  • an air distribution hood 202 is provided at the air inlet of the rotary kiln 2, and the first cooling gas is introduced into the center position inside the air distribution hood 202, that is, the first cooling gas is along the front direction of the air distribution hood 202
  • the air inlet 2021 enters, so that the first cooling gas is distributed in the central area of the rotary kiln 2
  • the second cooling gas is introduced into the periphery of the air distribution hood 202, that is, the second cooling gas enters along the tangential air inlet 2022 of the air distribution hood 202, so that
  • the second cooling gas is distributed in the peripheral area inside the rotary kiln 2, thereby forming a graded oxygen concentration distribution environment in the rotary kiln 2 with low oxygen content in the periphery and high oxygen content in the central area, so as to realize full oxygen combustion of fuel in the central area of the rotary kiln 2 Under the circumstances, the peripheral oxygen concentration of the rotary kiln
  • the burner 201 is inserted into the central position of the rotary kiln 2, so as to ensure that the fuel is sprayed to the central area of the rotary kiln 2 through the burner, and burns rapidly in the central area to form a high-temperature flame, further avoiding the high-temperature flame from interfering with the rotary kiln 2. wall contact.
  • the air outlet of the preheater 5 is connected to the first fan 13 through a third pipe 903, that is, the outlet of the first cyclone separator 501 in the figure.
  • the tuyere is connected to the first fan 13 through the third pipe 903, and the flue gas at the outlet of the first fan 13 is divided into two paths, the first flue gas D enters the waste gas treatment system through the fourth pipe 904, and the second flue gas enters
  • the fifth pipeline 905 of the second blower fan 14 is set, and the flue gas (the carbon dioxide content in the flue gas is greater than 70% in the flue gas) at the outlet of the fifth pipeline 905 is divided into the following three schemes for processing:
  • the above-mentioned first fan 13 is a high-temperature fan
  • the second fan 14 is a circulation fan.
  • the heat exchanger 15 is set so that the temperature of the flue gas at the outlet of the heat exchanger 15 drops below 100°C.
  • the heat exchanger 15 can use a waste heat power generation boiler or an air heat exchanger.
  • the flue gas entering the second fan 14 may have a high dust content. If the dust content is high, on the one hand, the dust will easily settle in the fifth pipe 905 between the second fan 14 and the cooling machine 1 to form accumulations. , increase pipeline resistance, on the other hand, high dust content will increase the wear of the second fan 14 . Therefore, as a preferred embodiment, the fifth duct 905 is provided with a dust collector 16 near the air inlet of the second fan 14 to remove dust from the flue gas that is about to enter the second fan 14 in advance, so that the second fan 14 The dust concentration in the air is reduced to below 100mg/m 3 .
  • the fifth pipe 905 is provided with a valve 10, so as to facilitate the adjustment of the flue gas circulation, so as to realize the temperature control of the gas exiting from the second cooling zone 3012 at 600-1000°C;
  • a valve 10 is set on the sixth pipeline 906, so as to facilitate the adjustment of the concentration of oxygen in the mixture of pure oxygen and carbon dioxide;
  • a valve 10 is arranged on the second pipeline 902, so as to facilitate the adjustment of the entering amount of the second cooling gas in the preheater.
  • FIG. 2 it is a flow chart of the method for producing cement clinker by using the above system.
  • the dotted line with arrows is the direction of air flow
  • the solid line with arrows is the direction of material flow.
  • the method for preparing cement clinker by the above system includes the following steps :
  • I-1 feed the raw meal R into the preheater 5, and the raw meal R is separated from the flue gas by heat exchange in the preheater 5 to obtain the preheated raw meal;
  • the hot raw meal enters the rotary kiln 2 through the smoke chamber, and is calcined in the rotary kiln 2 to form cement clinker K1 (as shown in Figure 4).
  • the temperature of the cement clinker K1 is 1300-1450 ° C.
  • the kiln outlet enters the cooler 3, and the specific operation is as follows:
  • the mixed gas of high-concentration pure oxygen A and carbon dioxide flue gas B passed into the first cooling zone 3011 cools the cement clinker for the first time to obtain the first cooling gas and the first cooling cement clinker;
  • the temperature of the first cooling gas is 900-1300°C.
  • the first cooling gas is divided into two paths.
  • the first cooling gas g1 of the first path enters along the forward air inlet 2021 of the air distribution hood 202 as the secondary air, so that the first The cooling gas g1 of the first road is distributed in the central area of the rotary kiln 2, and is used for fuel combustion in the rotary kiln 2.
  • the kiln gas formed by the fuel combustion in the rotary kiln 2 and the decomposition of part of the raw material enters the calciner 4, and the first cooling gas of the second road g2 enters the calciner 4 as tertiary air for fuel combustion
  • the first cooled cement clinker falls into the second cooling subregion 3012, and the carbon dioxide flue gas that passes into the second cooling subregion 3012 performs second cooling on the first cooled cement clinker to obtain the second cooling gas and the second cooled cement clinker ;
  • the temperature of the second cooling gas is 600-1000°C.
  • the second cooling gas is divided into two paths.
  • the second cooling gas g31 of the first path enters along the tangential air inlet 2022 of the air distribution hood 202 as the fourth air, so that the first
  • the second cooling gas g31 of the first road is distributed in the peripheral area inside the rotary kiln 2, and the gas volume of the second cooling gas g31 of the first road entering the rotary kiln is adjusted through the valve 10; the second cooling gas g32 of the second road enters the preheating The air inlet of device 5;
  • the second cooling cement clinker enters the second cooling zone 302, and the air C passing into the second cooling zone 302 cools the second cooling cement clinker for the third time to obtain the finished product K of cement clinker and the third cooling gas g4, cement
  • the finished clinker K temperature is about 100°C;
  • the third cooling gas g4 is used for the drying heat source of the raw material and fuel grinding system
  • the kiln gas entering the calciner 4 is mixed with the flue gas formed by fuel combustion and raw material decomposition in the calciner 4 to obtain a mixed flue gas product, and the mixed flue gas product enters the preheater 5 through the air outlet pipe of the calciner 4, Perform heat exchange with the raw meal in the preheater 5 and separate it into low-temperature flue gas, which is discharged from the top air outlet of the preheater 5, and the CO concentration in the low-temperature flue gas is 70-95%;
  • the second flue gas enters the dust collector 16 for dust removal treatment, and after passing through the second fan 14, it is mixed with pure oxygen as the circulating flue gas to become the above-mentioned mixed gas and enters the entrance of the first cooling zone 3011;
  • the second flue gas enters the dust collector 16 for dust removal treatment, and enters the entrance of the second cooling zone 3012 as circulating flue gas after passing through the second fan 14;
  • the second flue gas enters the dust collector 16 for dust removal treatment. After passing through the second fan 14, it is divided into two paths as circulating flue gas.
  • the first path of circulating flue gas is mixed with high-concentration pure oxygen to form the above-mentioned mixed gas and enters the first The inlet of the cooling zone 3011, the second channel of circulating flue gas enters the inlet of the second cooling zone 3012 ( Figure 2 shows the flow of this solution).

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Abstract

一种全氧燃烧循环预热生产水泥熟料的系统及方法，系统包括预热器、分解炉、烟室、回转窑以及冷却机，冷却机包括第一冷却区和第二冷却区，第一冷却区包括第一冷却分区和第二冷却分区，第一冷却分区的进口通入高浓度纯氧和二氧化碳烟气的混合气，第一冷却分区出口与回转窑进风口连通，第一冷却分区出口排出第一冷却气体作为二次风进入回转窑的进风口，第二冷却分区进口通入二氧化碳烟气，第二冷却分区出口通过第一管道与回转窑进风口连通，控制第二冷却分区出口排出的第二冷却气体作为四次风进入回转窑的进风口，从而调整回转窑内混合气体中O 2浓度，进而控制回转窑全氧燃烧的火焰温度。

Description

一种全氧燃烧生产水泥熟料的系统及方法 技术领域
本发明属于水泥工艺技术领域，尤其涉及一种全氧燃烧生产水泥熟料的系统及方法。
背景技术
随着全球气候变暖，二氧化碳的排放受到广泛关注。水泥生产过程会产生大量的二氧化碳，据统计，生产1t水泥会排放0.6～0.7t二氧化碳。水泥窑废气中二氧化碳主要来源于以下两个方面：
1、燃料燃烧烟气中生成的二氧化碳，占比约40％。
2、原料中碳酸盐分解产生的二氧化碳，占比约60％。
国际能源署(IEA)和水泥可持续发展倡议组织(CSI)合作开发的《2050水泥技术路线图》指出：碳捕集与封存技术是目前水泥行业减少二氧化碳排放最可行的新技术，预计在2050年可减少二氧化碳排放量56％。其中全氧燃烧技术在碳捕集与封存技术中发展前景较好。
全氧燃烧是指用工业氧气代替空气来燃烧燃料，可以使燃料燃烧更加完全，全氧燃烧相比空气燃烧有如下诸多优点：
1)全氧燃烧过程与空气燃烧相比，空气中约79％的氮气不再参与燃烧，可以提高火焰温度；
2)烟气中氮气含量少，燃烧产物为三原子产物，三原子物质的传热效果高于双原子的物质，提高加热效率；
3)氮气不再参与排烟，可以大幅减少烟气量，减少排烟热损失；
4)全氧燃烧技术能够节约燃料，减少NOx的排放，达到净化环境的要求。
目前，全氧燃烧技术在浮法玻璃、玻纤窑上应用广泛，在水泥窑的应用处于研发阶段，水泥窑主要是在分解炉以及回转窑内采用全氧燃烧技术。
其中，在水泥窑内采用全氧燃烧的一种方案如下：
将原有的冷却机分为第一冷却区和第二冷却区，第一冷却区通入纯氧和二氧化碳烟气的混合气与熟料进行换热，换热后的混合气一部分进入回转窑，另一部分进入分解炉，供回转窑以及分解炉内燃料全氧燃烧，第二冷却区通入常规空气与熟料进行换热，换热后的空气进行余热利用或排放。
上述方案存在如下问题：
1、通入回转窑内O 2/CO 2混合气中O 2浓度不易调整，从而无法控制回转窑全氧燃烧的火焰温度，这是因为通入第一级冷却区O 2/CO 2混合气中O 2浓度难以在实际生产运行过程中灵活调整。原因是：O 2/CO 2混合气通过冷却机第一冷却区后再进入回转窑供燃料燃烧，由于冷却机设备结构和篦床面积在运行过程中是固定不变的，第一冷却区的篦床面积对应的冷却风量相对固定，因此，若增加循环烟气量可降低O 2/CO 2混合气中O 2浓度，但会造成冷却风量增加，冷却风量增加会导致篦床阻力增加；若降低循环烟气量可增加O 2/CO 2混合气中O 2浓度，但会造成冷却风量降低，冷却风量降低会导致熟料在第一冷却区冷却不充分。
2、回转窑内燃烧火焰温度过高，内衬容易受损，尤其当燃烧过程中火焰的粗细和方向不稳定时，高温火焰容易与回转窑内衬接触，使回转窑内衬受损。
发明内容
为了克服现有技术的缺陷，本发明提供一种全氧燃烧生产水泥熟料的系统及方法，解决现有的水泥窑的全氧燃烧技术存在的通入回转窑内O 2/CO 2混合气中O 2浓度不易调整，从而无法控制回转窑全氧燃烧的火焰温度，以及回转窑内燃烧火焰温度过高，内衬容易受损的问题。
本发明通过如下技术方案实现：
本发明提供的一种全氧燃烧生产水泥熟料的系统，包括预热器、分解炉、烟室、回转窑以及冷却机，所述回转窑与所述冷却机连通，所述回转窑上设置燃烧器；其特征在于，所述冷却机包括第一冷却区和第二冷却区，所述第一冷却区包括第一冷却分区和第二冷却分区；
所述第一冷却分区的进口通入高浓度纯氧和二氧化碳烟气的混合气，所述第一冷却分区的出口与所述回转窑的进风口连通，第一冷却分区的出口排出第一冷却气体，第一冷却气体作为二次风进入所述回转窑的进风口，第一冷却气体为换热后的高浓度纯氧和二氧化碳烟气的混合气；
所述第二冷却分区的进口通入二氧化碳烟气，所述第二冷却分区的出口通过第一管道与所述回转窑的进风口连通，第二冷却分区的出口排出第二冷却气体，控制第二冷却气体作为四次风进入所述回转窑的进风口，第二冷却气体为换热后的二氧化碳烟气；
所述第二冷却区的进口通入空气，所述第二冷却区的出口排出第三冷却气体，第三冷却气体为换热后的空气。
进一步的，所述回转窑的进风口设置布风罩；
进入回转窑的所述第一冷却气体引入布风罩内侧中心位置，使得第一冷却气体分布在回转窑的中心区域；
进入回转窑的所述第二冷却气体引入布风罩的外围，使得第二冷却气体分布在回转窑内部的外围区域。
进一步的，所述燃烧器设置在回转窑的中心位置。
进一步的，所述第二冷却分区设于第一冷却分区和第二冷却区之间。
进一步的，所述冷却机采用篦式冷却机，所述篦式冷却机的中间设置辊式破碎机，将冷却机分为第一冷却区和第二冷却区。
进一步的，所述第一冷却区的中间设置隔墙，将所述第一冷却区分为第一冷却分区和第二冷却分区。
进一步的，所述第二冷却分区的出口还通过第二管道与所述预热器的进风口连通，将第二冷却分区的出口排出的部分第二冷却气体对预热器的生料进行预热。
进一步的，所述第一冷却分区的出口还通过三次风管与所述分解炉的进风口连通；
将第一冷却分区的出口排出的部分第一冷却气体作为三次风进入分解炉内供燃料燃烧。
进一步的，所述预热器的出风口通过第三管道与第一风机连接，第一风机的出风口的烟气分为两路，第一路烟气通过第四管道进入废气处理系统，第二路烟气进入设置第二风机的第五管道，第五管道出口的烟气作为循环烟气与高浓度纯氧混合成为所述混合气进入第一冷却分区的进口。
进一步的，所述预热器的出风口通过第三管道与第一风机连接，第一风机的出风口的烟气分为两路，第一路烟气通过第四管道进入废气处理系统，第二路烟气进入设置第二风机的第五管道，第五管道出口的烟气作为循环烟气进入第二冷却分区的进口。
进一步的，所述预热器的出风口通过第三管道与第一风机连接，第一风机的出风口的烟气分为两路，第一路烟气通过第四管道进入废气处理系统，第二路烟气进入设置第二风机的第五管道，第五管道出口的烟气作为循环烟气分为两路，第一路循环烟气进入第六管道与高浓度纯氧混合成为所述混合气进入第一冷却分区的进口，第二路循环烟气通过第七管道进入第二冷却分区的进口。
进一步的，所述第三管道上设置热交换器。
进一步的，所述第五管道在靠近所述第二风机的进风口位置设置收尘器。
进一步的，所述第一管道上设置阀门。
采用上述的系统生产水泥熟料的方法，包括如下步骤：
将生料喂入预热器，生料在预热器内与烟气进行换热分离，得到预热后的生料；
预热后的生料进入分解炉，分解炉内燃料燃烧释放大量热量供生料分解，得到热生料；
热生料通过烟室进入回转窑，在回转窑内煅烧形成水泥熟料，水泥熟料由回转窑出口进入冷却机，具体操作如下：
通入第一冷却分区的高浓度纯氧和二氧化碳烟气的混合气对水泥熟料进行第一次冷却，得到第一冷却气体和第一冷却水泥熟料；
所述第一冷却气体作为二次风进入所述回转窑的进风口，第一冷却气体为换热后的高浓度纯氧和二氧化碳烟气的混合气；
第一冷却水泥熟料落入第二冷却分区，通入第二冷却分区的二氧化碳烟气对第一冷却水泥熟料进行第二次冷却，得到第二冷却气体和第二冷却水泥熟料；
控制所述第二冷却气体作为四次风进入所述回转窑的进风口，第二冷却气体为换热后的二氧化碳烟气；
第二冷却水泥熟料进入第二冷却区，通入第二冷却区的空气对第二冷却水泥熟料进行第三次冷却，得到水泥熟料成品以及第三冷却气体，第三冷却气体为换热后的空气；
进入分解炉的窑气与分解炉内燃料燃烧和生料分解形成的烟气混合得到混合烟气产物，混合烟气产物经分解炉进入预热器，与预热器内的生料进行换热分离成为低温烟气，低温烟气从预热器的顶端出风口排出。
进一步的，进入所述回转窑的所述第一冷却气体分布在所述回转窑的中心区域，进入所述回转窑的所述第二冷却气体分布在所述回转窑内部的外围区域。
进一步的，从预热器的顶端出风口排出的低温烟气包括如下三种处理路线：
排出的低温烟气进入第一风机，第一风机的出风口的烟气分为两路，第一路烟气进入废气处理系统，第二路烟气经过第二风机后作为循环烟气与高浓度纯氧混合成为所述混合气进入第一冷却分区的进口；
排出的低温烟气进入第一风机，第一风机的出风口的烟气分为两路，第一路烟气进入废气处理系统，第二路烟气经过第二风机后作为循环烟气进入第二冷却分区的进口；
排出的低温烟气进入第一风机，第一风机的出风口的烟气分为两路，第一路烟气进入废气处理系统，第二路烟气经过第二风机后作为循环烟气分为两路，第一路循环烟气与高浓度纯氧混合成为所述混合气进入第一冷却分区的进口，第二路循环烟气进入第二 冷却分区的进口。
进一步的，第一冷却气体还作为三次风进入分解炉内供燃料燃烧。
进一步的，所述第二冷却气体还进入预热器的进风口，实现对预热器的生料进行预热。
进一步的，排出的低温烟气进入第一风机前，先进入热交换器进行换热利用。
进一步的，所述第二路烟气在进入第二风机前，先进入收尘器进行除尘处理。
和最接近的现有技术比，本发明的技术方案具备如下有益效果：
本发明提供的全氧燃烧生产水泥熟料的系统，冷却机包括第一冷却区和第二冷却区，第一冷却区包括第一冷却分区和第二冷却分区，第一冷却分区的进口通入高浓度纯氧和二氧化碳烟气的混合气，第一冷却分区的出口与回转窑的进风口连通，第一冷却分区的出口排出的第一冷却气体(即换热后的高浓度纯氧和二氧化碳烟气的混合气)作为二次风进入回转窑的进风口，第二冷却分区的进口通入二氧化碳烟气，第二冷却分区的出口通过第一管道与回转窑的进风口连通，控制第二冷却分区的出口排出的第二冷却气体(即换热后的二氧化碳烟气)作为四次风进入所述回转窑的进风口，优选是通过在第一管道上设置阀门的方式控制第二冷却分区的出口排出的第二冷却气体(即换热后的二氧化碳烟气)进入所述回转窑的进风口，从而调整回转窑内混合气体中O 2浓度，进而控制回转窑全氧燃烧的火焰温度。
在回转窑的进风口设置布风罩，进入回转窑的第一冷却气体引入布风罩内侧中心位置，使得第一冷却气体分布在回转窑的中心区域，进入回转窑的第二冷却气体引入布风罩的外围，使得第二冷却气体分布在回转窑内部的外围区域，从而在回转窑内形成外围氧含量低、中心区氧含量高的分级氧浓度分布环境，从而实现燃料在回转窑中心区域全氧燃烧的情况下，回转窑的外围氧浓度低，形成低氧浓度惰性气体保护层，阻碍了回转窑内高温火焰向外围扩散，防止高温火焰与回转窑壁面接触，从而防止回转窑内衬被高温火焰烧损，提升水泥窑全氧燃烧下的设备安全性。并且作为优选的，将燃烧器插入到回转窑的中心位置，从而保证燃料通过燃烧器喷射到回转窑的中心区域，在中心区快速燃烧形成高温火焰，进一步避免高温火焰与回转窑壁面接触。
采用通入二氧化碳烟气的第二冷却分区阻断第一冷却分区和第二冷却区之间的空气窜风，从而避免进入第一冷却分区的二氧化碳浓度降低，进而提升水泥生产系统的碳富集效果。
第二冷却分区的出口还通过第二管道与预热器的进风口连通，从而将冷却水泥熟料 后的二氧化碳烟气的高温热量用于预热器内生料换热，从而降低水泥生产系统的热能耗。
全氧燃烧条件下，由于几乎没有氮气存在，回转窑中高温燃烧过程几乎不会有热力型NOx的形成。同时，烟气循环后，循环烟气中的NOx再次进入系统，延长了NOx的还原周期，增强了还原效果，降低了NOx排放。同时，循环烟气中SO 2进入窑内，与CaO反应生产硫酸盐，降低废气中的SO 2排放。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为本发明的全氧燃烧生产水泥熟料的系统的结构示意图；
图2为采用全氧燃烧生产水泥熟料的的方法流程图。
图3为本发明的回转窑局部示意图；
图4为图3的侧视图；
其中，1-烟室，2-回转窑，201-燃烧器，202-布风罩，2021-正向进风口，2022-切向进风口，3-冷却机，301-第一冷却区，3011-第一冷却分区，3012-第二冷却分区，302-第二冷却区，4-分解炉，401-出风管，5-预热器，501-第一旋风分离器，502-第二旋风分离器，503-第三旋风分离器，504-第四旋风分离器，505-第五旋风分离器，601-第一进风管，602-第二进风管，603-第三进风管，604-第四进风管，7-连通管道，8-三次风管，901-第一管道，902-第二管道，903-第三管道，904-第四管道，905-第五管道，906-第六管道，907-第七管道，10-阀门，11-辊式破碎机，12-隔墙,13-第一风机，14-第二风机,15-热交换器,16-收尘器。
具体实施方式
下面将结合本发明的实施例，对本发明的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
在本发明的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位 或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。此外，术语“第一”、“第二”等仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”等的特征可以明示或者隐含地包括一个或者更多个该特征。在本发明的描述中，除非另有说明，“多个”的含义是两个或两个以上。
在本发明的描述中，需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通。对于本领域的普通技术人员而言，可以通过具体情况理解上述术语在本发明中的具体含义。
下面将参考附图并结合实施例来详细说明本发明。
如图1所示，为本实施例的全氧燃烧生产水泥熟料的系统的结构示意图，图中带箭头虚线为气流方向，带箭头实线为料流方向，全氧燃烧生产水泥熟料的系统包括烟室1、回转窑2、冷却机3以及生料预热预分解系统。
生料预热预分解系统与烟室1连通，回转窑2上设置燃烧器201,燃烧器201内通入燃料F，回转窑2的尾部与烟室1连通，回转窑2的头部与冷却机3连通。生料预热预分解系统包括分解炉4和预热器5，预热器5优选为旋风预热器，图中示意的预热器5为旋风预热器，并且旋风预热器仅采用1列旋风预热器，需要说明的是图中旋风预热器的列数仅为示意，本领域技术人员可以根据实际需要设定。
分解炉4上设置燃烧器，燃烧器内通入燃料F,分解炉4的侧壁开设生料入口，分解炉4的顶部设置出风管401，需要说明的是，出风管401也可以设置在分解炉4的侧面。
上述预热器5的底端进风口连接分解炉4的出风管401，预热器5的顶端出风口排出低温烟气，预热器5的顶端进料口用于生料R进料，预热器5的底端出料口连通烟室1，具体的，图中示意旋风预热器包括依次连通的第一旋风分离器501、第二旋风分离器502、第三旋风分离器503、第四旋风分离器504和第五旋风分离器505，需要说明的是图中旋风分离器的个数仅为示意，本领域技术人员可以根据需要设定。
第一旋风分离器501的顶端开设出风口，出风口排出低温烟气，第一旋风分离器501的顶端侧面与第一进风管601连通，第一进风管501上开设进料口，进料口用于生料进料，第一旋风分离器501的底端与第二进风管602连通。
第二旋风分离器502的顶端与第一进风管601连通，第二旋风分离器502的顶端侧面和第二进风管602连通，第二旋风分离器502的底端与第三进风管603连通。
第三旋风分离器503的顶端与第二进风管602连通，第三旋风分离器503的顶端侧面和第三进风管603连通，第三旋风分离器503的底端与第四进风管604连通。
第四旋风分离器504的顶端与第三进风管603连通，第四旋风分离器504的顶端侧面和第四进风管604连通，第四旋风分离器504的底端与分解炉4的生料入口连通。
第五旋风分离器505的顶端与第四进风管604连通，第五旋风分离器505的顶端侧面开设进风口，进风口通过连通管道7与分解炉4的出风管401连通，第五旋风分离器505的底端开设出料口，出料口与烟室1连通。
上述冷却机3采用篦式冷却机，篦式冷却机的中间设置辊式破碎机11，将冷却机3分为第一冷却区301和第二冷却区302，第一冷却区301的中间设置隔墙12，将第一冷却区301分为第一冷却分区3011和第二冷却分区3012，第二冷却分区3012设在第一冷却分区3011和第二冷却区302之间。
第一冷却分区3011的进口通入高浓度纯氧A和二氧化碳烟气的混合气，混合气中氧气浓度为50-98％，第二冷却分区3012的进口通入二氧化碳烟气B，二氧化碳烟气B中氧气浓度低于10％，第二冷却区302的进口通入空气C，空气的输出源可以为风机，纯氧可以是制氧系统制取，也可以购买，纯氧纯度优选区间为85-98％。
将冷却机3采用上述分区设置，能够阻断第一冷却分区3011和第二冷却区3012之间的空气窜风，从而避免进入第一冷却分区3011的二氧化碳浓度降低，进而提升水泥生产系统的碳富集效果。
作为优选实施例，第一冷却分区3011的出口排出第一冷却气体，第一冷却气体为换热后的高浓度纯氧和二氧化碳烟气的混合气，第一冷却气体分为两路，第一路的第一冷却气体g1作为二次风直接进入回转窑2内供燃料燃烧，第二路的第一冷却气体g2作为三次风通过三次风管8进入分解炉4内供燃料燃烧。
第二冷却分区3012的出口排出第二冷却气体，第二冷却气体为换热后的高温二氧化碳烟气，第二冷却气体分为两路，第一路的第二冷却气体g31作为四次风通过第一管道901进入回转窑的进风口，并在第一管道901上设置阀门10，通过阀门10调整第二冷却气体进入回转窑内的气体量，从而调整回转窑内混合气体中O 2浓度，进而控制回转窑全氧燃烧的火焰温度。第二路的第二冷却气体g32通过第二管道902进入预热器5的进风口，即进入第五旋风分离器505的进风口，从而将冷却水泥熟料后的二氧化碳烟气 的高温热量用于预热器内生料换热，从而降低水泥生产系统的热能耗。
第二冷却区302的出口排出第三冷却气体g4，第三冷却气体g4为换热后的空气，第三冷却气体g4温度为200-300℃，用于原料、燃料粉磨系统烘干热源，从而进一步充分利用水泥生产系统产生的热源，并且水泥熟料经过第二冷却区302冷却后得到水泥熟料成品K。
如图3-4，作为优选实施例，在回转窑2的进风口设置布风罩202，第一冷却气体引入布风罩202内侧中心位置，即第一冷却气体沿布风罩202的正向进风口2021进入，使得第一冷却气体分布在回转窑2的中心区域，第二冷却气体引入布风罩202的外围，即第二冷却气体沿布风罩202的切向进风口2022进入，使得第二冷却气体分布在回转窑2内部的外围区域，从而在回转窑2内形成外围氧含量低、中心区氧含量高的分级氧浓度分布环境，从而实现燃料在回转窑2中心区域全氧燃烧的情况下，回转窑2的外围氧浓度低，形成低氧浓度惰性气体保护层，阻碍了回转窑2内高温火焰向外围扩散，防止高温火焰与回转窑2壁面接触，从而防止回转窑2内衬被高温火焰烧损，提升水泥窑全氧燃烧下的设备安全性。并且作为优选的，将燃烧器201插入到回转窑2的中心位置，从而保证燃料通过燃烧器喷射到回转窑2的中心区域，在中心区快速燃烧形成高温火焰，进一步避免高温火焰与回转窑2壁面接触。
作为优选实施例，为了实现对预热器出口的烟气进行充分利用，预热器5的出风口通过第三管道903与第一风机13连接，即图中的第一旋风分离器501的出风口通过第三管道903与第一风机13连接，第一风机13的出风口的烟气分为两路，第一路烟气D通过第四管道904进入废气处理系统，第二路烟气进入设置第二风机14的第五管道905，第五管道905出口的烟气(烟气中二氧化碳含量大于70)分如下三种方案处理：
方案1：第五管道905出口的烟气作为循环烟气与纯氧混合成为上述的混合气进入第一冷却分区3011的进口。
方案2：第五管道905出口的烟气作为循环烟气进入第二冷却分区3012的进口。
方案3：第五管道905出口的烟气作为循环烟气分为两路，第一路循环烟气进入第六管道906与纯氧混合成为所述混合气进入第一冷却分区3011的进口，第二路循环烟气通过第七管道907进入第二冷却分区3012的进口。
上述第一风机13采用高温风机，第二风机14采用循环风机。
由于从预热器出风口排出的烟气需要作为冷却介质进入冷却机3内，为避免烟气温度过高不利于冷却机3内熟料冷却，作为优选实施例，在上述第三管道903上设置热交 换器15，从而使得热交换器15出口的烟气温度降至100℃以下，优选的，热交换器15可以采用余热发电锅炉或者空气换热器。
进入第二风机14内的烟气可能存在粉尘含量高的情况，若粉尘含量较高的话，一方面，粉尘容易在第二风机14与冷却机1之间的第五管道905内沉降形成积料，增加管道阻力，另一方面，粉尘含量高会增加第二风机14的磨损。因此，作为优选实施例，第五管道905在靠近上述第二风机14的进风口位置设置收尘器16，提前对即将进入第二风机14内的烟气进行除尘处理，从而使得第二风机14中的粉尘浓度降低至100mg/m 3以下。
作为优选实施例，第五管道905上设置阀门10，从而便于调节烟气循环量，从而实现从第二冷却分区3012出口的气体温度控制在600-1000℃；
第六管道906上设置阀门10，从而便于调节纯氧和二氧化碳混合气中氧气的浓度；
第二管道902上设置阀门10，从而便于调节预热器内第二冷却气体的进入量。
如图2所示，为采用上述系统生产水泥熟料的方法流程图，图中带箭头虚线为气流方向，带箭头实线为料流方向，采用上述系统制备水泥熟料的方法，包括如下步骤：
I-1将生料R喂入预热器5，生料R在预热器5内与烟气进行换热分离，得到预热后的生料；
I-2预热后的生料进入分解炉4，分解炉4内燃料燃烧释放大量热量供生料分解，得到热生料；
I-3热生料通过烟室进入回转窑2，在回转窑2内煅烧形成水泥熟料K1(如图4所示)，水泥熟料K1温度为1300-1450℃，水泥熟料K1由回转窑出口进入冷却机3，具体操作如下：
通入第一冷却分区3011的高浓度纯氧A和二氧化碳烟气B的混合气对水泥熟料进行第一次冷却，得到第一冷却气体和第一冷却水泥熟料；
第一冷却气体的温度为900-1300℃，第一冷却气体分为两路，第一路的第一冷却气体g1作为二次风沿布风罩202的正向进风口2021进入，使得第一路冷却气体g1分布在回转窑2的中心区域，供回转窑2内供燃料燃烧，回转窑2内燃料燃烧和部分生料分解形成的窑气进分解炉4，第二路的第一冷却气体g2作为三次风进入分解炉4内供燃料燃烧
第一冷却水泥熟料落入第二冷却分区3012，通入第二冷却分区3012的二氧化碳烟气对第一冷却水泥熟料进行第二次冷却，得到第二冷却气体和第二冷却水泥熟料；
第二冷却气体的温度为600-1000℃，第二冷却气体分为两路，第一路的第二冷却气体g31作为四次风沿布风罩202的切向进风口2022进入，使得第一路的第二冷却气体g31分布在回转窑2内部的外围区域，通过阀门10调整第一路的第二冷却气体g31进入回转窑内的气体量；第二路的第二冷却气体g32进入预热器5的进风口；
第二冷却水泥熟料进入第二冷却区302，通入第二冷却区302的空气C对第二冷却水泥熟料进行第三次冷却，得到水泥熟料成品K以及第三冷却气体g4，水泥熟料成品K温度为100℃左右；
第三冷却气体g4用于原料、燃料粉磨系统烘干热源；
I-4进入分解炉4的窑气与分解炉4内燃料燃烧和生料分解形成的烟气混合得到混合烟气产物，混合烟气产物经分解炉4的出风管进入预热器5，与预热器5内的生料进行换热分离成为低温烟气，低温烟气从预热器5的顶端出风口排出，低温烟气中CO 2浓度为70-95％；
I-5排出的低温烟气(烟气中二氧化碳含量为70-95％)经过热交换器15换热后进入第一风机13，第一风机13的出风口的烟气分为两路，第一路烟气D进入废气处理系统，第二路烟气分为如下三种方案处理：
1、第二路烟气进入收尘器16进行除尘处理，经过第二风机14后作为循环烟气与纯氧混合成为上述混合气进入第一冷却分区3011的进口；
2、第二路烟气进入收尘器16进行除尘处理，经过第二风机14后作为循环烟气进入第二冷却分区3012的进口；
3、第二路烟气进入收尘器16进行除尘处理，经过第二风机14后作为循环烟气分为两路，第一路循环烟气与高浓度纯氧混合成为上述混合气进入第一冷却分区3011的进口，第二路循环烟气进入第二冷却分区3012的进口(图2示意的是本方案的流程)。
以上实施例仅用以说明本发明的技术方案而非对其限制，尽管参照上述实施例对本发明进行了详细的说明，所属领域的普通技术人员依然可以对本发明的具体实施方式进行修改或者等同替换，这些未脱离本发明精神和范围的任何修改或者等同替换，均在申请待批的本发明的权利要求保护范围之内。

Claims (21)

  1. 一种全氧燃烧生产水泥熟料的系统，包括预热器、分解炉、烟室、回转窑以及冷却机，所述回转窑与所述冷却机连通，所述回转窑上设置燃烧器；其特征在于，所述冷却机包括第一冷却区和第二冷却区，所述第一冷却区包括第一冷却分区和第二冷却分区；
    所述第一冷却分区的进口通入高浓度纯氧和二氧化碳烟气的混合气，所述第一冷却分区的出口与所述回转窑的进风口连通，第一冷却分区的出口排出第一冷却气体，第一冷却气体作为二次风进入所述回转窑的进风口，第一冷却气体为换热后的高浓度纯氧和二氧化碳烟气的混合气；
    所述第二冷却分区的进口通入二氧化碳烟气，所述第二冷却分区的出口通过第一管道与所述回转窑的进风口连通，第二冷却分区的出口排出第二冷却气体，控制第二冷却气体作为四次风进入所述回转窑的进风口，第二冷却气体为换热后的二氧化碳烟气；
    所述第二冷却区的进口通入空气，所述第二冷却区的出口排出第三冷却气体，第三冷却气体为换热后的空气。
  2. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述回转窑的进风口设置布风罩；
    进入回转窑的所述第一冷却气体引入布风罩内侧中心位置，使得第一冷却气体分布在回转窑的中心区域；
    进入回转窑的所述第二冷却气体引入布风罩的外围，使得第二冷却气体分布在回转窑内部的外围区域。
  3. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述燃烧器设置在回转窑的中心位置。
  4. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述第二冷却分区设于第一冷却分区和第二冷却区之间。
  5. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述冷却机采用篦式冷却机，所述篦式冷却机的中间设置辊式破碎机，将冷却机分为第一冷却区和第二冷却区。
  6. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述第一冷却区的中间设置隔墙，将所述第一冷却区分为第一冷却分区和第二冷 却分区。
  7. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述第二冷却分区的出口还通过第二管道与所述预热器的进风口连通，将第二冷却分区的出口排出的部分第二冷却气体对预热器的生料进行预热。
  8. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述第一冷却分区的出口还通过三次风管与所述分解炉的进风口连通；
    将第一冷却分区的出口排出的部分第一冷却气体作为三次风进入分解炉内供燃料燃烧。
  9. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述预热器的出风口通过第三管道与第一风机连接，第一风机的出风口的烟气分为两路，第一路烟气通过第四管道进入废气处理系统，第二路烟气进入设置第二风机的第五管道，第五管道出口的烟气作为循环烟气与高浓度纯氧混合成为所述混合气进入第一冷却分区的进口。
  10. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述预热器的出风口通过第三管道与第一风机连接，第一风机的出风口的烟气分为两路，第一路烟气通过第四管道进入废气处理系统，第二路烟气进入设置第二风机的第五管道，第五管道出口的烟气作为循环烟气进入第二冷却分区的进口。
  11. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述预热器的出风口通过第三管道与第一风机连接，第一风机的出风口的烟气分为两路，第一路烟气通过第四管道进入废气处理系统，第二路烟气进入设置第二风机的第五管道，第五管道出口的烟气作为循环烟气分为两路，第一路循环烟气进入第六管道与高浓度纯氧混合成为所述混合气进入第一冷却分区的进口，第二路循环烟气通过第七管道进入第二冷却分区的进口。
  12. 根据权利要求9-11任一项所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述第三管道上设置热交换器。
  13. 根据权利要求9-11任一项所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述第五管道在靠近所述第二风机的进风口位置设置收尘器。
  14. 根据权利要求1所述的一种全氧燃烧生产水泥熟料的系统，其特征在于，所述第一管道上设置阀门。
  15. 采用如权利要求1所述的系统生产水泥熟料的方法，其特征在于，包括如下步骤：
    将生料喂入预热器，生料在预热器内与烟气进行换热分离，得到预热后的生料；
    预热后的生料进入分解炉，分解炉内燃料燃烧释放大量热量供生料分解，得到热生料；
    热生料通过烟室进入回转窑，在回转窑内煅烧形成水泥熟料，水泥熟料由回转窑出口进入冷却机，具体操作如下：
    通入第一冷却分区的高浓度纯氧和二氧化碳烟气的混合气对水泥熟料进行第一次冷却，得到第一冷却气体和第一冷却水泥熟料；
    所述第一冷却气体作为二次风进入所述回转窑的进风口，第一冷却气体为换热后的高浓度纯氧和二氧化碳烟气的混合气；
    第一冷却水泥熟料落入第二冷却分区，通入第二冷却分区的二氧化碳烟气对第一冷却水泥熟料进行第二次冷却，得到第二冷却气体和第二冷却水泥熟料；
    控制所述第二冷却气体作为四次风进入所述回转窑的进风口，第二冷却气体为换热后的二氧化碳烟气；
    第二冷却水泥熟料进入第二冷却区，通入第二冷却区的空气对第二冷却水泥熟料进行第三次冷却，得到水泥熟料成品以及第三冷却气体，第三冷却气体为换热后的空气；
    进入分解炉的窑气与分解炉内燃料燃烧和生料分解形成的烟气混合得到混合烟气产物，混合烟气产物经分解炉进入预热器，与预热器内的生料进行换热分离成为低温烟气，低温烟气从预热器的顶端出风口排出。
  16. 根据权利要求15所述的生产水泥熟料的方法，其特征在于，进入所述回转窑的所述第一冷却气体分布在所述回转窑的中心区域，进入所述回转窑的所述第二冷却气体分布在所述回转窑内部的外围区域。
  17. 根据权利要求15所述的生产水泥熟料的方法，其特征在于，从预热器的顶端出风口排出的低温烟气包括如下三种处理路线：
    排出的低温烟气进入第一风机，第一风机的出风口的烟气分为两路，第一路烟气进入废气处理系统，第二路烟气经过第二风机后作为循环烟气与高浓度纯氧 混合成为所述混合气进入第一冷却分区的进口；
    排出的低温烟气进入第一风机，第一风机的出风口的烟气分为两路，第一路烟气进入废气处理系统，第二路烟气经过第二风机后作为循环烟气进入第二冷却分区的进口；
    排出的低温烟气进入第一风机，第一风机的出风口的烟气分为两路，第一路烟气进入废气处理系统，第二路烟气经过第二风机后作为循环烟气分为两路，第一路循环烟气与高浓度纯氧混合成为所述混合气进入第一冷却分区的进口，第二路循环烟气进入第二冷却分区的进口。
  18. 根据权利要求15所述的生产水泥熟料的方法，其特征在于，第一冷却气体还作为三次风进入分解炉内供燃料燃烧。
  19. 根据权利要求15所述的生产水泥熟料的方法，其特征在于，所述第二冷却气体还进入预热器的进风口，实现对预热器的生料进行预热。
  20. 根据权利要求17所述的生产水泥熟料的方法，其特征在于，排出的低温烟气进入第一风机前，先进入热交换器进行换热利用。
  21. 根据权利要求17所述的生产水泥熟料的方法，其特征在于，所述第二路烟气在进入第二风机前，先进入收尘器进行除尘处理。
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