WO2022001109A1 - 一种链箅机预热段防窜风系统及其风流控制方法 - Google Patents

一种链箅机预热段防窜风系统及其风流控制方法 Download PDF

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WO2022001109A1
WO2022001109A1 PCT/CN2021/075587 CN2021075587W WO2022001109A1 WO 2022001109 A1 WO2022001109 A1 WO 2022001109A1 CN 2021075587 W CN2021075587 W CN 2021075587W WO 2022001109 A1 WO2022001109 A1 WO 2022001109A1
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preheating
stage
section
tph
air
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PCT/CN2021/075587
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English (en)
French (fr)
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胡兵
曾辉
刘臣
魏进超
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中冶长天国际工程有限责任公司
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Priority to BR112022004907A priority Critical patent/BR112022004907A2/pt
Publication of WO2022001109A1 publication Critical patent/WO2022001109A1/zh

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B19/00—Combinations of furnaces of kinds not covered by a single preceding main group
    • F27B19/04—Combinations of furnaces of kinds not covered by a single preceding main group arranged for associated working
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/90—Injecting reactants
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B1/00—Preliminary treatment of ores or scrap
    • C22B1/14—Agglomerating; Briquetting; Binding; Granulating
    • C22B1/16—Sintering; Agglomerating
    • C22B1/20—Sintering; Agglomerating in sintering machines with movable grates
    • 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
    • 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
    • F27D15/00—Handling or treating discharged material; Supports or receiving chambers therefor
    • F27D15/02—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
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • 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
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
    • 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
    • F27D19/00—Arrangements of controlling devices
    • 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
    • F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
    • F27D7/02—Supplying steam, vapour, gases, or liquids
    • 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
    • F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
    • F27D7/02—Supplying steam, vapour, gases, or liquids
    • F27D2007/026—Dampers
    • 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
    • F27D19/00—Arrangements of controlling devices
    • F27D2019/0028—Regulation

Definitions

  • the invention relates to an anti-channeling wind system of a chain grate machine, in particular to an anti-channeling wind system of a preheating section of a chain grate machine and a wind flow control method thereof, belonging to the technical field of flue gas treatment of a chain grate machine.
  • NOx is the main reason for the formation of photochemical smog, acid rain, and haze weather, which aggravates the destruction of the ozone layer and promotes the greenhouse effect, which is harmful to the ecological environment.
  • 2019 Eco-Environment Department issued the "Opinions on Promoting the implementation of ultra-low emissions of the steel industry," clearly requires pellet sintering flue gas at a reference oxygen content of 18%, NOx emissions hour average concentration of not more than 50mg / m 3 . If the oxygen content is higher than 18%, the NOx concentration shall be evaluated according to the value converted to the reference oxygen content.
  • the NOx emission concentration is generally 100-300 mg/m 3
  • the oxygen content in the exhaust gas is 17%-19%.
  • the production of NOx in the pellet production process mainly comes from fuel type and thermal type. Although it can be reduced by reducing the output of pellets, that is, reducing the amount of gas or pulverized coal injected, and by reducing the strength requirements of the pellets, that is, reducing the rotary kiln
  • the production of chain grate-rotary kiln pellets can be reduced by adopting lower NOx raw materials and fuels and other measures, but it is difficult to meet the environmental protection requirements of ultra-low emissions.
  • the preferred NOx removal technology mainly relies on selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) technology, which remove NOx at the end and in the process, respectively.
  • SCR selective catalytic reduction
  • SNCR selective non-catalytic reduction
  • the temperature range of 800°C to 1100°C is suitable.
  • SNCR denitrification technology is applied in the production process of chain grate machine-rotary kiln pellets.
  • reducing agent ammonia or urea
  • SNCR technology in series with SCR technology is an effective means to achieve ultra-low emission of pellet flue gas.
  • the present invention proposes an anti-channeling wind system in the preheating section of the chain grate machine.
  • the denitration treatment can meet the ultra-low emission requirements of pellet NOx, and the investment and operating costs are greatly reduced.
  • the bellows of the TPH section close to the PH section is selectively incorporated into the PH section, which prolongs the high temperature preheating time of the pellets and improves the strength of the preheating ball.
  • a wind blowing prevention system in the preheating section of a chain grate machine, and the system includes a chain grate machine and a rotary kiln.
  • the chain grate machine is sequentially provided with a blast drying section, a suction drying section, a preheating section and a preheating section.
  • the second preheating section is communicated with the flue gas outlet of the rotary kiln through the first pipe.
  • a blow-by air device is arranged between the preheating first stage and the preheating second stage.
  • the anti-wind blowing device includes an air balance plate, a moving platform, a roller and a slot.
  • the air balance plate is arranged inside the chain grate machine.
  • the moving platforms are arranged on both sides of the outer lower ends of the first stage of preheating and the second stage of preheating.
  • the rollers are arranged at the bottom of the moving platform.
  • the slots are provided on both sides of the outer upper ends of the first stage of preheating and the second stage of preheating.
  • the mobile platform is also provided with a fixed seat.
  • a column is arranged on the fixed seat. The top end of the column is connected with the top end of the airflow balance plate after passing through the slot.
  • a moving motor is also provided outside the moving platform. The moving motor drives the moving platform to move on the rollers.
  • the movement of the mobile platform drives the movement of the fixed seat and the upright column, thereby driving the movement of the airflow balance plate in the chain grate machine.
  • the airflow balance plate is composed of an outer plate and an inner plate.
  • the outer plate is an inner hollow plate body.
  • the inner plate is sleeved in the inner cavity of the outer plate.
  • the inner plate is also connected with the lift motor.
  • the lift motor controls the inner plate to move in the vertical direction of the inner cavity of the outer plate.
  • the system also includes an ammonia agent denitration device.
  • the ammonia agent denitrification device is arranged in the second preheating section and/or the first pipeline.
  • the ammonia agent denitration device includes a first sprayer, a second sprayer and an ammonia agent storage tank.
  • the first sprinkler is arranged in the second preheating section.
  • the second sprinkler is disposed within the first conduit.
  • the ammonia agent storage tank is connected with the first sprayer through a second pipeline.
  • a third pipe branched from the second pipe is connected to the second sprinkler.
  • the system also includes an SCR denitration device and a dust removal device.
  • the air outlet of the second preheating section is connected to the air inlet of the air extraction and drying section through a fourth pipeline.
  • the air outlet of the air extraction and drying section is connected to the chimney through a fifth pipe.
  • the SCR denitration device is arranged on the fourth pipeline.
  • the dust removal device is arranged on the fifth pipe.
  • the system also includes an annular cooler.
  • the annular cooling machine is sequentially provided with a first stage of annular cooling, a second stage of annular cooling and a third stage of annular cooling.
  • the air outlet of the annular cooling section is connected to the air inlet of the rotary kiln through the sixth pipeline.
  • the air outlet of the second ring cooling stage is connected to the air inlet of the preheating stage through the seventh pipeline.
  • the air outlet of the third ring cooling section is connected to the air inlet of the blast drying section through the eighth pipeline.
  • the air outlet of the preheating section is connected to the fifth duct through the ninth duct.
  • the air outlet of the blast drying section is connected to the chimney through the tenth pipe.
  • the system further includes a first pressure detector, a second pressure detector, a first temperature detector, a second temperature detector, a first flow detector, a second flow detector and a flue gas analyzer.
  • the first pressure detector, the first temperature detector and the flue gas analyzer are arranged in the preheating section.
  • the second pressure detector and the second temperature detector are arranged in the second preheating section.
  • the first flow detector is arranged on the seventh pipeline.
  • the second flow detector is arranged on the first pipeline.
  • the green balls enter the chain grate machine, pass through the blast drying section, the exhaust drying section, the preheating section and the preheating section, and then are transported to the rotary kiln for oxidation roasting.
  • the oxidized pellets after oxidative roasting are transported to a ring cooler for cooling.
  • the hot air discharged from the first stage of ring cooling is transported to the rotary kiln through the sixth pipeline, and then transported to the second stage of preheating through the first pipeline.
  • the hot air discharged from the second stage of ring cooling is transported to the first stage of preheating through the seventh pipeline.
  • the adjustment of the horizontal position of the anti-channel wind device disposed between the first stage of preheating and the second stage of preheating includes:
  • the mobile platform is driven by the mobile motor to move on the rollers; the movement of the mobile platform drives the movement of the fixed seat and the column, thereby driving the movement of the airflow balance plate in the chain grate machine;
  • the inner plate of the airflow balance plate is controlled to move in the vertical direction of the inner cavity of the outer plate of the airflow balance plate by the lifting and lowering motor.
  • the method further includes: a first pressure detector is arranged in the preheating section to detect in real time the air pressure in the preheating section as p1, Pa.
  • a first temperature detector is also provided to detect in real time that the gas in the preheating section is stable as c1, K.
  • a second pressure detector is arranged in the second preheating stage to detect the air pressure in the second preheating stage as p2, Pa in real time.
  • a second temperature detector is also provided to detect the gas stability in the second stage of preheating as c2, K in real time.
  • a first flow detector is also provided on the seventh pipeline to detect in real time the gas flow delivered to the first stage of preheating as q1, Nm 3 /h.
  • a second flow detector is arranged on the first pipeline to detect the gas flow delivered to the second preheating section in real time as q2, Nm 3 /h. Then the mass of gas delivered to the preheating section is m1, g:
  • the mass of gas delivered to the second preheating stage is m2, g:
  • ⁇ is the average density of the gas, g/m 3 .
  • t is the gas delivery time, h.
  • v1 is the volume of the preheating stage, m 3 .
  • v2 is the volume of the second preheating stage, m 3 .
  • R is the gas constant, J/(mol ⁇ K).
  • M is the average molar mass of the gas, g/mol.
  • the length of the preheating stage is set as a1, the width as b1, and the height as h1, and the unit is m.
  • the k1 is the volume correction ratio of the preheating stage.
  • k2 is the volume correction ratio of the second stage of preheating.
  • the horizontal displacement of the airflow balance plate is adjusted to be ⁇ a, it is a step-by-step adjustment, and the number of adjustments is set to N, then:
  • N
  • the number of movements of the airflow balance plate is the calculated value N of the formula X.
  • a flue gas analyzer Y is also provided in the first stage of preheating to detect in real time that the NOx content in the first stage of preheating is less than or equal to 40 mg/m 3 .
  • the chain grate machine is divided into a blast drying section, an exhaust air drying section, a preheating section and a preheating section. Ring cooling three sections. Among them, the air in the first stage of ring cooling directly enters the rotary kiln to roast the pellets. After the second stage of preheating, the preheated balls are heated and then blown into the draft drying section to dry the green pellets. The air in the second stage of annular cooling enters the preheating stage to heat the preheating balls and then discharges to the outside; the air in the third stage of annular cooling enters the blast drying section to blast and dry the green balls, so as to realize the chain grate.
  • SNCR selective non-catalytic reduction technology
  • SCR selective catalytic reduction technology
  • SNCR+SCR double denitration mechanism a production system with ultra-low NOx emission from pellet flue gas (201821480691.X), through the effective combination of SNCR+SCR double denitration mechanism, can achieve ultra-low NOx emission in the production process of chain grate-rotary kiln pellets.
  • the precise control of denitration and the emission of NOx up to the standard are implemented.
  • a movable anti-channel wind device is added between the PH section and the TPH section of the machine, and the position change of the anti-channel wind device is used to mainly control the air pressure P1 of the TPH section to be greater than or equal to the air pressure P2 of the PH section, that is, P1 ⁇ P2, to prevent high NOx in the PH section
  • the exhaust gas flows to the TPH section, which increases the NOx content in the flue gas of the TPH section.
  • the air flow balance plate of the chain grate machine is opened before the air flow system is not balanced, and it is closed in time after stabilization, which has a positive impact on the chain grate machine system: only SNCR+SCR denitrification treatment is required for the exhaust gas in the PH section (about 1/3) to meet the pelletizing requirements. NOx ultra-low emission requirements, investment and operating costs are greatly reduced; multiple bellows (usually 1-5, which can be reasonably adjusted according to actual working conditions) close to the PH section in the TPH section are selectively incorporated into the PH section, indirectly It prolongs the high temperature preheating time of pellets and improves the strength of the preheating balls.
  • the air pressure in the preheating stage is detected as p1, Pa in real time by setting the first pressure detector in the preheating stage.
  • a second pressure detector is arranged in the second preheating stage to detect the air pressure in the second preheating stage as p2, Pa in real time.
  • the system does not adjust (the position of the airflow balance plate remains unchanged); if the detected p1 ⁇ p2, the position of the airflow balance plate is controlled and adjusted to make p1 ⁇ p2. In order to prevent the high NOx exhaust gas in the PH section from blowing to the TPH section.
  • the anti-wind blowing device includes an air balance plate, a moving platform, a roller and a slot.
  • the air balance plate is arranged inside the chain grate machine.
  • the moving platforms are arranged on both sides of the outer lower ends of the first stage of preheating and the second stage of preheating.
  • the rollers are arranged at the bottom of the moving platform.
  • the slots are provided on both sides of the outer upper ends of the first stage of preheating and the second stage of preheating.
  • the mobile platform is also provided with a fixed seat. A column is arranged on the fixed seat.
  • the top end of the upright column is connected to the top end of the airflow balance plate after passing through the slot (the top end of the upright column is transversely bent and then connected to the top end of the air flow balance plate through the slot).
  • a moving motor is also provided outside the moving platform. The moving motor drives the moving platform to move on the rollers. The movement of the mobile platform drives the movement of the fixed seat and the column, which in turn drives the movement of the airflow balance plate in the chain grate machine (moving from the PH section to the TPH section).
  • the airflow balance plate is composed of an outer plate and an inner plate.
  • the outer plate is an inner hollow plate body.
  • the inner plate is sleeved in the inner cavity of the outer plate.
  • the inner plate is also connected with the lift motor.
  • the lift motor controls the inner plate to move in the vertical direction of the inner cavity of the outer plate. According to the actual needs, adjust the movement of the inner plate, and then change the overall height of the airflow balance plate to meet the needs of different heights and prevent the occurrence of wind channeling.
  • the thickness of the inner plate is 1-20 cm, preferably 2-15 cm, more preferably 3-10 cm.
  • the thickness of the outer plate (that is, the overall thickness of the airflow balance plate) is 3-25 cm, preferably 5-20 cm, more preferably 8-15 cm.
  • the thickness of the inner cavity of the outer plate is greater than the thickness of the inner plate (for example, the thickness of the inner cavity of the outer plate is 0.5cm, 1cm, 1.5cm, 2cm, etc., which can be selected according to the actual working conditions).
  • the gas temperature in the first stage of preheating is detected as c1, K in real time by arranging a first temperature detector in the first stage of preheating.
  • a second temperature detector is arranged in the second preheating stage to detect the gas temperature in the second preheating stage as c2, K in real time.
  • the seventh pipeline is also provided with a first flow detector to detect in real time the gas flow delivered to the first stage of preheating as q1, Nm 3 /h.
  • a second flow detector is arranged on the first pipeline to detect the gas flow delivered to the second preheating section in real time as q2, Nm 3 /h. Then it can be calculated that the mass of gas delivered to the preheating section is m1, g:
  • the mass of gas delivered to the second preheating stage is m2, g:
  • ⁇ is the average density of the gas, g/m 3 .
  • t is the gas delivery time, h.
  • v1 is the volume of the preheating stage, m 3 .
  • v2 is the volume of the second preheating stage, m 3 .
  • R is the gas constant, J/(mol ⁇ K).
  • M is the average molar mass of the gas, g/mol.
  • the length of the preheating stage is set as a1, the width as b1, and the height as h1, and the unit is m.
  • the k1 is the volume correction ratio of the preheating stage.
  • k2 is the volume correction ratio of the second stage of preheating.
  • the correction values k1 and k2 are introduced, so that the calculation can obtain The volume is closest to the actual volume.
  • the values of k1 and k2 are fixed constants.
  • the airflow balance plate When p1 ⁇ p2, it is necessary to move the airflow balance plate (the initial position of the airflow balance plate is the junction of the preheating stage 1 and the preheating stage 2) so that p1 ⁇ p2, and set the horizontal movement of the airflow balance board in the direction of the preheating stage 1
  • the amount is ⁇ a, m. but:
  • N
  • the number of movements of the airflow balance plate is the calculated value N of the formula X.
  • the determination of the N value needs to be based on the degree of urgency of adjustment (the less p1 is than p2, the less the number of adjustments should be, because it is necessary to reduce as soon as possible. Pressure difference).
  • a new pressure detection needs to be performed after each adjustment of the step size. If the target is not reached (p1 ⁇ p2), it will continue. If the target is reached, stop the adjustment.
  • a flue gas analyzer is also arranged in the preheating stage to detect in real time that the NOx content in the preheating stage is less than or equal to 40 mg/m 3 .
  • the final emission concentration of NOx can be lower than 50mg/m 3 .
  • the present invention has the following beneficial technical effects:
  • the system of the present invention mainly controls the air pressure in the TPH section to be greater than or equal to the air pressure in the PH section by adding a movable anti-channeling wind device between the PH section and the TPH section of the chain grate machine, and using the position change of the anti-channeling wind device to prevent
  • the high NOx exhaust gas in the PH section is crossed to the TPH section, which increases the NOx content in the flue gas in the TPH section. Effectively reduce the direct emission of pollutants.
  • the chain grate air flow system of the present invention only needs to perform SNCR+SCR denitration treatment on the exhaust gas (about 1/3) of the PH section to meet the ultra-low emission requirements of pellet NOx, and the investment and operation costs are greatly reduced; Part of the bellows near the PH section of the TPH section is selectively incorporated into the PH section, which indirectly prolongs the high temperature preheating time of the pellets and improves the strength of the preheating ball.
  • the system of the present invention is simple in structure, easy to operate, low in cost and investment, has remarkable effect of wind control and emission reduction, and has strong application prospects and greater economic benefits.
  • the air flow control method of the present invention is simple and accurate, and the control process is short. Through real-time data monitoring, a response can be made in a very short time. At the same time, a dynamic fine-tuning can be realized by the way of air flow balance plate edge movement and calculation. , which not only makes the adjustment of the airflow balance plate more scientific and reasonable, but also can effectively avoid the problem that the production quality index is affected by the production fluctuation caused by the excessive adjustment step.
  • FIG. 1 is a schematic structural diagram of the anti-channel wind system in the preheating section of the chain grate machine according to the present invention.
  • FIG. 2 is a schematic structural diagram of the detection mechanism of the anti-channeling wind system in the preheating section of the chain grate machine according to the present invention.
  • FIG. 3 is a schematic view of the structure of the anti-channel wind device of the present invention.
  • FIG. 4 is a schematic structural diagram of the airflow balance plate of the present invention.
  • FIG. 5 is a top view of the structure of the anti-channel wind device of the present invention.
  • FIG. 6 is a flow chart of the air flow control and adjustment method of the present invention.
  • a wind blowing prevention system in the preheating section of a chain grate machine, and the system includes a chain grate machine 1 and a rotary kiln 2 .
  • the chain grate machine 1 is sequentially provided with a blast drying section UDD, a suction drying section DDD, a preheating section TPH and a preheating second section PH.
  • the second preheating stage PH is communicated with the flue gas outlet of the rotary kiln 2 through the first pipeline L1.
  • An anti-channel wind device 3 is arranged between the first stage of preheating TPH and the second stage of preheating PH.
  • the anti-wind blowing device 3 includes an airflow balance plate 301 , a moving platform 302 , a roller 303 and a slot 304 .
  • the airflow balance plate 301 is arranged inside the chain grate machine 1 .
  • the moving platform 302 is arranged on both sides of the outer lower ends of the preheating first stage TPH and the preheating second stage PH.
  • the rollers 303 are arranged at the bottom of the moving platform 302 .
  • the slots 304 are provided on both sides of the outer upper ends of the preheating first stage TPH and the preheating second stage PH.
  • the mobile platform 302 is also provided with a fixed seat 30201 .
  • a column 30202 is arranged on the fixing seat 30201 .
  • the top of the column 30202 is connected to the top of the airflow balance plate 301 after passing through the slot 304 .
  • a moving motor 30203 is also provided outside the moving platform 302 .
  • the moving motor 30203 drives the moving platform 302 to move on the rollers 303 .
  • the movement of the mobile platform 302 drives the movement of the fixed seat 30201 and the upright column 30202 and further drives the movement of the airflow balance plate 301 in the chain grate machine 1 .
  • the airflow balance plate 301 is composed of an outer plate 30101 and an inner plate 30102.
  • the outer plate 30101 is a hollow plate body.
  • the inner plate 30102 is sleeved in the inner cavity of the outer plate 30101 .
  • the inner plate 30102 is also connected to the lift motor 30103 .
  • the lift motor 30103 controls the inner plate 30102 to move in the vertical direction of the inner cavity of the outer plate 30101 .
  • the system also includes an ammonia agent denitration device 4 .
  • the ammonia agent denitrification device 4 is arranged in the second-stage preheating PH and/or the first pipeline L1.
  • the ammonia agent denitration device 4 includes a first sprayer 401 , a second sprayer 402 and an ammonia agent storage tank 403 .
  • the first sprinkler 401 is arranged in the second stage of preheating PH.
  • the second sprinkler 402 is arranged in the first pipe L1.
  • the ammonia agent storage tank 403 is connected with the first sprayer 401 through the second pipeline L2.
  • a third pipe L3 is branched from the second pipe L2 and is connected to the second sprinkler 402 .
  • the system also includes an SCR denitration device 5 and a dust removal device 6 .
  • the air outlet of the second preheating section PH is connected to the air inlet of the extraction and drying section DDD through the fourth pipeline L4.
  • the air outlet of the air extraction and drying section DDD is communicated to the chimney through the fifth duct L5.
  • the SCR denitration device 5 is arranged on the fourth pipeline L4.
  • the dust removal device 6 is arranged on the fifth pipe L5.
  • the system also includes an annular cooler 7 .
  • the annular cooling machine 7 is sequentially provided with a first stage C1 of annular cooling, a second stage C2 of annular cooling, and a third stage C3 of annular cooling.
  • the air outlet of the ring cooling section C1 is connected to the air inlet of the rotary kiln 2 through the sixth pipeline L6.
  • the air outlet of the second ring cooling stage C2 is connected to the air inlet of the preheating stage TPH through the seventh pipeline L7.
  • the air outlet of the third ring cooling section C3 is connected to the air inlet of the blast drying section UDD through the eighth pipeline L8.
  • the air outlet of the preheating stage TPH is communicated to the fifth duct L5 through the ninth duct L9.
  • the air outlet of the blast drying section UDD is communicated to the chimney through the tenth pipe L10.
  • the system further includes a first pressure detector P1, a second pressure detector P2, a first temperature detector T1, a second temperature detector T2, a first flow detector Q1, a second flow detector Q2 and Flue gas analyzer Y.
  • the first pressure detector P1, the first temperature detector T1 and the flue gas analyzer Y are set in the preheating section TPH.
  • the second pressure detector P2 and the second temperature detector T2 are arranged in the second stage of preheating PH.
  • the first flow detector Q1 is arranged on the seventh pipeline L7.
  • the second flow detector Q2 is arranged on the first pipeline L1.
  • the green balls enter the chain grate machine 1, pass through the blast drying section UDD, the exhaust drying section DDD, the preheating section TPH and the preheating section PH, and then are transported to the rotary kiln 2 for oxidation roasting.
  • the oxidized pellets after oxidative roasting are sent to the ring cooler 7 for cooling.
  • the hot air discharged from the first stage C1 of the ring cooling is transported to the rotary kiln 2 through the sixth pipeline L6, and then transported to the second stage PH of the preheating through the first pipeline L1.
  • the hot air discharged from the second stage C2 of ring cooling is transported to the first stage TPH of preheating through the seventh pipeline L7.
  • the adjustment is set at the horizontal position of the anti-channel wind device 3 between the preheating stage TPH and the preheating stage PH, including:
  • the mobile platform 302 is driven by the mobile motor 30203 to move on the rollers 303; the movement of the mobile platform 302 drives the movement of the fixed seat 30201 and the upright column 30202 and then drives the movement of the airflow balance plate 301 in the chain grate machine 1;
  • the inner plate 30102 of the airflow balance plate 301 is controlled to move in the vertical direction of the inner cavity of the outer plate 30101 of the airflow balance plate 301 by the lift motor 30103 .
  • the method further includes: a first pressure detector P1 is arranged in the first stage of preheating TPH to detect in real time the air pressure in the first stage of preheating TPH as p1, Pa.
  • a first temperature detector T1 is also provided for real-time detection of the gas temperature in the first stage of preheating TPH as c1, K.
  • a second pressure detector P2 is arranged in the preheating second stage PH to detect the air pressure in the preheating second stage PH in real time as p2, Pa.
  • a second temperature detector T2 is also provided to detect the gas temperature in the second stage PH of preheating in real time as c2, K.
  • a first flow detector Q1 is also provided on the seventh pipeline L7 to detect in real time the gas flow delivered to the first stage of preheating TPH as q1, Nm 3 /h.
  • a second flow detector Q2 is arranged on the first pipeline L1 to detect the gas flow delivered to the second preheating stage PH in real time as q2, Nm 3 /h. Then the mass of gas delivered to the preheating section of TPH is m1, g:
  • the mass of gas delivered to the preheating second stage TPH is m2, g:
  • ⁇ is the average density of the gas, g/m 3 .
  • t is the gas delivery time, h.
  • v1 is the volume of preheated one-stage TPH, m 3 .
  • v2 is the volume of the preheating second stage PH, m 3 .
  • R is the gas constant, J/(mol ⁇ K).
  • M is the average molar mass of the gas, g/mol.
  • the length of a preheating stage of TPH is set to be a1, the width to be b1, and the height to be h1, and the units are all m.
  • V2 k2*a2*b2*h2...Formula VI.
  • the k1 is the volume correction ratio of the preheating stage TPH.
  • k2 is the volume correction ratio of the preheating second stage PH.
  • the horizontal movement amount of the airflow balance plate 301 in the direction of the preheating stage TPH is set as ⁇ a, m. but:
  • the horizontal displacement of the airflow balance plate 301 is adjusted to be ⁇ a, it is a step-by-step adjustment, and the adjustment times are set to N, then:
  • N (p2-p1)/(0.05*p1)....Formula X.
  • the number of movements of the airflow balance plate 301 is the calculated value N of the formula X.
  • a flue gas analyzer Y is also provided in the first stage of preheating TPH to detect in real time that the NOx content in the first stage of preheating TPH is less than or equal to 40 mg/m 3 .
  • an anti-channel wind system in the preheating section of a chain grate machine includes a chain grate machine 1 and a rotary kiln 2 .
  • the chain grate machine 1 is sequentially provided with a blast drying section UDD, a suction drying section DDD, a preheating section TPH and a preheating second section PH.
  • the second preheating stage PH is communicated with the flue gas outlet of the rotary kiln 2 through the first pipeline L1.
  • An anti-channel wind device 3 is arranged between the first stage of preheating TPH and the second stage of preheating PH.
  • the anti-wind blowing device 3 includes an airflow balance plate 301 , a moving platform 302 , a roller 303 and a slot 304 .
  • the airflow balance plate 301 is arranged inside the chain grate machine 1 .
  • the moving platform 302 is arranged on both sides of the outer lower ends of the preheating first stage TPH and the preheating second stage PH.
  • the rollers 303 are arranged at the bottom of the moving platform 302 .
  • the slots 304 are provided on both sides of the outer upper ends of the preheating first stage TPH and the preheating second stage PH.
  • the mobile platform 302 is also provided with a fixed seat 30201 .
  • a column 30202 is arranged on the fixing seat 30201 .
  • the top of the column 30202 is connected to the top of the airflow balance plate 301 after passing through the slot 304 .
  • a moving motor 30203 is also provided outside the moving platform 302 .
  • the moving motor 30203 drives the moving platform 302 to move on the rollers 303 .
  • the movement of the mobile platform 302 drives the movement of the fixed seat 30201 and the upright column 30202 and further drives the movement of the airflow balance plate 301 in the chain grate machine 1 .
  • Example 2 is repeated.
  • the airflow balance plate 301 is composed of an outer plate 30101 and an inner plate 30102 .
  • the outer plate 30101 is a hollow plate body.
  • the inner plate 30102 is sleeved in the inner cavity of the outer plate 30101 .
  • the inner plate 30102 is also connected to the lift motor 30103 .
  • the lift motor 30103 controls the inner plate 30102 to move in the vertical direction of the inner cavity of the outer plate 30101 .
  • Example 3 is repeated, and on the basis of Example 3, the system also includes an ammonia agent denitration device 4 .
  • the ammonia agent denitration device 4 is arranged in the preheating second stage PH and/or the first pipeline L1.
  • Example 4 is repeated.
  • the ammonia agent denitrification device 4 includes a first sprayer 401 , a second sprayer 402 and an ammonia agent storage tank 403 .
  • the first sprinkler 401 is arranged in the second stage of preheating PH.
  • the second sprinkler 402 is arranged in the first pipe L1.
  • the ammonia agent storage tank 403 is connected with the first sprayer 401 through the second pipeline L2.
  • a third pipe L3 is branched from the second pipe L2 and is connected to the second sprinkler 402 .
  • Example 5 is repeated. On the basis of Example 5, the system further includes an SCR denitration device 5 and a dust removal device 6 .
  • the air outlet of the second preheating section PH is connected to the air inlet of the extraction and drying section DDD through the fourth pipeline L4.
  • the air outlet of the air extraction and drying section DDD is communicated to the chimney through the fifth duct L5.
  • the SCR denitration device 5 is arranged on the fourth pipeline L4.
  • the dust removal device 6 is arranged on the fifth pipe L5.
  • Example 6 is repeated.
  • the system further includes an annular cooler 7 .
  • the annular cooling machine 7 is sequentially provided with a first stage C1 of annular cooling, a second stage C2 of annular cooling, and a third stage C3 of annular cooling.
  • the air outlet of the ring cooling section C1 is connected to the air inlet of the rotary kiln 2 through the sixth pipeline L6.
  • the air outlet of the second ring cooling stage C2 is connected to the air inlet of the preheating stage TPH through the seventh pipeline L7.
  • the air outlet of the third ring cooling section C3 is connected to the air inlet of the blast drying section UDD through the eighth pipeline L8.
  • the air outlet of the preheating stage TPH is communicated to the fifth duct L5 through the ninth duct L9.
  • the air outlet of the blast drying section UDD is communicated to the chimney through the tenth pipe L10.
  • Example 7 is repeated.
  • the system further includes a first pressure detector P1, a second pressure detector P2, a first temperature detector T1, a second temperature detector T2, and a first flow detector Q1, the second flow detector Q2 and the flue gas analyzer Y.
  • the first pressure detector P1, the first temperature detector T1 and the flue gas analyzer Y are set in the preheating section TPH.
  • the second pressure detector P2 and the second temperature detector T2 are arranged in the second stage of preheating PH.
  • the first flow detector Q1 is arranged on the seventh pipeline L7.
  • the second flow detector Q2 is arranged on the first pipeline L1.
  • the volume correction ratio k1 of the preheating stage of TPH is 1.
  • the volume correction ratio k2 of the preheating second stage PH is 1 (that is, the preheating first stage TPH of the chain grate machine and the preheating second stage PH are both rectangular).
  • the gas flow rate q1 delivered to the preheating section TPH was 100Nm 3 /h. It is detected that the gas flow rate q2 delivered to the preheating second stage PH is 150Nm 3 /h. It is detected that the gas temperature in the preheating section of TPH is 858.15K. It is detected that the gas temperature in the PH of the second stage of preheating is 1250.15K.
  • N (p2-p1)/(0.05*p1)....Formula X.
  • p1 and p2 are detected. If p1 ⁇ p2, the adjustment of the airflow balance plate 301 is completed; Plate 301 is adjusted until p1 ⁇ p2.

Abstract

本发明公开了一种链箅机预热段防窜风系统及其风流控制方法，该系统包括链箅机和回转窑。所述链箅机依次设有鼓风干燥段、抽风干燥段、预热一段和预热二段。所述预热二段通过第一管道与回转窑的烟气出口相连通。所述预热一段和预热二段之间设置有防窜风装置。本发明通过在链箅机PH段和TPH段之间增设可移动式防窜风装置，利用防窜风装置位置变化来控制TPH段的气压大于等于PH段的气压，防止PH段高NOx废气向TPH段窜风导致TPH段烟气中NOx含量升高的问题。通过风流控制的方法的精确调控，实现超低NOx排放。

Description

一种链箅机预热段防窜风系统及其风流控制方法 技术领域
本发明涉及链箅机防窜风系统，具体涉及一种链箅机预热段防窜风系统及其风流控制方法，属于链箅机烟气处理技术领域。
背景技术
NOx是形成光化学烟雾、酸雨、灰霾天气，加剧臭氧层破坏和促进温室效应的主要原因，对生态环境危害巨大。2019年生态环境部发布了《关于推进实施钢铁行业超低排放的意见》，明确要求球团焙烧烟气在基准含氧量18％的条件下，NOx小时均值排放浓度不高于50mg/m 3。如果氧含量高于18％，则NOx浓度按折算到基准氧含量后的值进行考核。因此，要满足钢铁烧结、球团工业大气污染物排放要求，同时降低焙烧烟气中NOx的浓度和氧气浓度是有效的技术措施。从大多数的球团厂生产情况来看，NOx一般排放浓度在100～300mg/m 3，废气中的氧气含量17％-19％。
球团生产过程NOx的产生主要源于燃料型和热力型两种形式，虽然可以通过降低球团矿产量，即减少煤气或煤粉喷入量，通过降低球团矿强度要求，即降低回转窑温度，通过采用较低NOx的原料和燃料等措施来减少链箅机-回转窑球团生产过程NOx的生成量，但是难以满足超低排放的环保要求。
在现有技术中，由于没有系统的研究和可靠的链箅机-回转窑球团生产过程低NOx生成和控制技术，造成球团厂生产过程NOx排放不达标成为常态，是企业面临的最大挑战之一。为此，企业只能通过降低球团矿产量，从而减少煤气或煤粉喷入量、降低球团矿强度要求，从而降低回转窑温度和采用较低NOx的原料和燃料等方式来降低NOx的生成。这些方式不仅在产量和质量上影响了球团矿生产，对原燃料的质量要求也很高，造成成本的增加，而且不能从根本上解决球团低NOx生产的难题。
目前，较为优选的NOx的脱除技术主要依靠选择性催化还原技术(SCR)和选择性非催化还原技术(SNCR)，分别在末端和过程中对NOx进行脱除。对SNCR脱硝技术来说，一般认为温度范围为800℃～1100℃较为适宜。链箅机-回转窑球团生产过程应用SNCR脱硝技术，通常是在预热二段(温度范围850℃～1100℃)处向烟气中喷洒还原剂(氨水或尿素)进行烟气脱硝。SNCR技术串联SCR技术更是实现球团烟气超低排放的有效手段。面对强烈的环保气压，一种球团烟气超低NOx排放的生产系统被提出(201821480691.X)，通过SNCR+SCR双重脱硝机制的有效结合，可实现链箅机-回转窑球团生产过程NOx的超低排。但是往往由于链箅机生产系统中PH段与TPH段因温度、气压差别而导致的串风问题，即PH段高NOx废气向TPH段串风，使得TPH段烟气中NOx含量升高。进而难以实现脱硝精准控制和NOx的达标排放。
发明内容
针对现有技术的不足，本发明提出了一种链箅机预热段防窜风系统，通过在链箅机PH段和TPH段之间增设可移动式气流平衡板，利用气流平衡板位置变化来控制TPH段的气 压大于等于PH段的气压，进而防止PH段高NOx废气向TPH段窜风，使得TPH段烟气中NOx含量升高的问题。链箅机防窜风系统的气流未平衡前打开气流平衡板，待气流稳定后及时关闭，对链箅机系统产生积极影响：即只需对PH段废气(约1/3)进行SNCR+SCR脱硝处理即可满足球团NOx超低排放要求，投资和运行成本大大减少。同时通过控制气流平衡板向TPH端的移动，间接性的将TPH段靠近PH段的风箱选择性的并入PH段，延长了球团高温预热时间，起到改善预热球强度的作用。
为实现上述目的，本发明所采用的技术方案具体如下：
根据本发明的第一种实施方案，提供一种链箅机预热段防窜风系统，该系统包括链箅机和回转窑。根据物料的走向，所述链箅机依次设有鼓风干燥段、抽风干燥段、预热一段和预热二段。所述预热二段通过第一管道与回转窑的烟气出口相连通。所述预热一段和预热二段之间设置有防窜风装置。
作为优选，所述防窜风装置包括气流平衡板、移动平台、辊轮以及开槽。所述气流平衡板设置在链箅机的内部。所述移动平台设置在预热一段和预热二段外部下端的两侧。所述辊轮设置在移动平台底部。所述开槽开设在预热一段和预热二段外部上端的两侧。所述移动平台上还设置有固定座。所述固定座上设置有立柱。所述立柱的顶端穿过开槽后与气流平衡板的顶端相连接。所述移动平台的外部还设置有移动电机。移动电机驱动移动平台在辊轮上进行移动。移动平台的移动带动固定座、立柱的移动进而带动气流平衡板在链箅机内的移动。
作为优选，所述气流平衡板由外板和内板组成。所述外板为一个内部中空的板体。所述内板套接在外板的内腔中。所述内板还与升降电机相连。升降电机控制内板在外板内腔的竖直方向上进行移动。
作为优选，该系统还包括有氨剂脱硝装置。所述氨剂脱硝装置设置在预热二段和/或第一管道内。
作为优选，所述氨剂脱硝装置包括有第一喷洒器、第二喷洒器和氨剂储存罐。所述第一喷洒器设置在预热二段内。所述第二喷洒器设置在第一管道内。所述氨剂储存罐通过第二管道与第一喷洒器相连接。所述第二管道上分出第三管道与第二喷洒器相连接。
作为优选，该系统还包括有SCR脱硝装置和除尘装置。所述预热二段的出风口通过第四管道连通至抽风干燥段的进风口。所述抽风干燥段的出风口通过第五管道连通至烟囱。所述SCR脱硝装置设置在第四管道上。所述除尘装置设置在第五管道上。
作为优选，该系统还包括有环冷机。所述环冷机依次设有环冷一段、环冷二段以及环冷三段。所述环冷一段的出风口通过第六管道连通至回转窑的进风口。所述环冷二段的出风口通过第七管道连通至预热一段的进风口。所述环冷三段的出风口通过第八管道连通至鼓风干燥段的进风口。所述预热一段的出风口通过第九管道连通至第五管道。所述鼓风干燥段的出风口通过第十管道连通至烟囱。
作为优选，该系统还包括有第一压力检测计、第二压力检测计、第一温度检测计、第二温度检测计、第一流量检测计、第二流量检测计以及烟气分析仪。所述第一压力检测计、第一温度检测计和烟气分析仪设置在预热一段内。所述第二压力检测计和第二温度检测计设置在预热二段内。所述第一流量检测计设置在第七管道上。所述第二流量检测计设置在第一管道上。
根据本发明的第二种实施方案，提供一种链箅机预热段风流控制方法或使用第一种实施方案所述链箅机预热段防窜风系统进行风流控制的方法，该方法包括如下步骤：
1)根据物料的走向，生球进入链箅机，依次经过鼓风干燥段、抽风干燥段、预热一段和预热二段后输送至回转窑内进行氧化焙烧。氧化焙烧完成后的氧化球团矿输送至环冷机进行冷却。
2)根据热风的流向，环冷一段排出的热风经由第六管道输送至回转窑内，然后再经第一管道输送至预热二段内。环冷二段排出的热风经由第七管道输送至预热一段内。
3)调节设置在预热一段和预热二段之间的防窜风装置的水平位置，使得预热一段内的压力大于或等于预热二段内的压力。
4)预热一段内的热风最后经由第九管道排出。预热二段内的热风最后经由第四管道排出。
可选地，该方法中，所述调节设置在预热一段和预热二段之间的防窜风装置的水平位置，包括：
通过移动电机驱动移动平台在辊轮上进行移动；移动平台的移动带动固定座、立柱的移动进而带动气流平衡板在链箅机内的移动；
通过升降电机控制所述气流平衡板的内板在所述气流平衡板的外板内腔的竖直方向上进行移动。
作为优选，该方法还包括：在预热一段内设置有第一压力检测计实时检测预热一段内的气压为p1，Pa。还设置有第一温度检测计实时检测预热一段内的气体稳定为c1，K。
作为优选，在预热二段内设置有第二压力检测计实时检测预热二段内的气压为p2，Pa。还设置有第二温度检测计实时检测预热二段内的气体稳定为c2，K。
作为优选，在第七管道上还设置有第一流量检测计实时检测输送至预热一段内的气体流量为q1，Nm 3/h。在第一管道上设置有第二流量检测计实时检测输送至预热二段内的气体流量为q2，Nm 3/h。则输送至预热一段内的气体质量为m1，g：
m1＝ρ*q1*t...式I。
输送至预热二段内的气体质量为m2，g：
m2＝ρ*q2*t...式II。
在式I和式II中，ρ为气体平均密度，g/m 3。t为气体输送时间，h。
根据理想气体状态方程，得：
p1*v1＝ρ*q1*t*R*c1/M...式III。
p2*v2＝ρ*q2*t*R*c2/M...式IV。
在式III和式IV中，v1为预热一段的容积，m 3。v2为预热二段的容积，m 3。R为气体常量，J/(mol·K)。M为气体平均摩尔质量，g/mol。
作为优选，设定预热一段的长度为a1，宽度为b1，高度为h1，单位均为m。设定预热二段的长度为a2，宽度为b2，高度为h2，单位均为m。则：
v1＝k1*a1*b1*h1...式V。
v2＝k2*a2*b2*h2...式VI。
在式V和式VI中，所述k1为预热一段的容积修正比值。k2为预热二段的容积修正比值。
将式V代入式III，得：
p1＝ρ*q1*t*R*c1/(M*k1*a1*b1*h1)...式VII。
将式VI代入式IV，得：
p2＝ρ*q2*t*R*c2/(M*k2*a2*b2*h2)...式VII。
设定气流平衡板向预热一段方向的水平移动量为△a，m。则：
Z＝p1/p2＝[q1*c1*k2*(a2-△a)*b2*h2]/[q2*c2*k1*(a1+△a)*b1*h1]...式VIII。
当Z＝1时，则气流平衡板的最小应移动量△a min为：
Figure PCTCN2021075587-appb-000001
通过调节气流平衡板的水平移动量△a大于等于式IX的计算值△a min，m，进而使得Z≥1，即p1≥p2。
作为优选，调节所述气流平衡板水平位移为△a时为分步调节，调整次数设为N，则：
N＝丨(p2-p1)/(0.05*p1)丨...式X。
当所述气流平衡板的所需水平位移为△a时，则气流平衡板的移动次数是式X的计算值N。
作为优选，在预热一段内还设置有烟气分析仪Y实时检测预热一段内的NOx的含量小于等于40mg/m 3。
在现有技术上，由于没有系统的研究和可靠的链箅机-回转窑球团生产过程低NOx生成和控制技术，造成球团厂生产过程NOx排放不达标成为常态，是企业面临的最大挑战之一。为此，企业只能通过降低球团矿产量，从而减少煤气或煤粉喷入量、降低球团矿强度要求，从而降低回转窑温度和采用较低NOx的原料和燃料等方式来降低NOx的生成。这些方式不仅在产量和质量上影响了球团矿生产，对原燃料的质量要求也很高，造成成本的增加，而且不能从根本上解决球团低NOx生产的难题。除此之外，通过在主抽风机之后增设脱硝装置，如采用选择性催化还原技术(SCR)和非选择性催化还原技术(SNCR)，虽然可以达到低NOx排放的要求，但由于其投资成本高、设备要求高、能耗大、脱硝成本高及存在二次污染，在球团企业没有得到推广应用，目前国内外球团厂NOx控制方式主要还是通过过程控制实现。
现有的链箅机-回转窑球团生产工艺中，链箅机分成鼓风干燥段、抽风干燥段、预热一段和预热二段，环冷机分成环冷一段、环冷二段和环冷三段。其中，环冷一段的风直接进入回转窑中焙烧球团矿，经预热二段加热预热球后鼓入到抽风干燥段对生球进行抽风干燥，再经抽风干燥段向外排放(排放之前经过烟气净化处理)；环冷二段的风进入预热一段加热预热球后向外排放；环冷三段的风进入鼓风干燥段对生球进行鼓风干燥，从而实现链箅机-回转窑-环冷机风流系统的闭路循环。同时采用选择性非催化还原技术(SNCR)串联选择性催化还原技术(SCR)，分别在过程中(预热二段内)和末端(预热二段排气口之后)对NOx进行脱除。如，一种球团烟气超低NOx排放的生产系统(201821480691.X)，通过SNCR+SCR双重脱硝机制的有效结合，可实现链箅机-回转窑球团生产过程NOx的超低排。但是往往由于链箅机生产系统中PH段与TPH段因温度、气压差别而导致的窜风问题，即PH段高NOx废气向TPH段串风，使得TPH段烟气中NOx含量升高。进而难以实现脱硝精准控制和NOx的达标排放。
在本发明中，为解决球团烟气超低NOx排放的生产系统中PH段与TPH段因温度、气压差别而导致的串风问题，实施脱硝精准控制和NOx达标排放，本发明在链箅机PH段和TPH段之间增设可移动式防窜风装置，利用防窜风装置位置变化来主要控制TPH段的气压P1大于等于PH段的气压P2，即P1≥P2，防止PH段高NOx废气向TPH段串风，使得TPH段烟气中NOx含量升高。链箅机风流系统未平衡前打开气流平衡板，稳定后及时关闭，对链箅机系统产生积极影响：只需对PH段废气(约1/3)进行SNCR+SCR脱硝处理即可满足球团NOx超低排放要求，投资和运行成本大大减少；将TPH段靠近PH段的多个风箱(一般为1-5个，可根据实际工况进行合理调节设置)选择性的并入PH段，间接延长了球团高温预热时间，起到改善预热球强度的作用。
在本发明中，通过在预热一段内设置有第一压力检测计实时检测预热一段内的气压为p1，Pa。在预热二段内设置有第二压力检测计实时检测预热二段内的气压为p2，Pa。通过将检测得到的p1和p2值进行对比。若检测到的p1≥p2，则系统不进行调整(气流平衡板位置维持不变)；若检测到的p1＜p2，则控制并调节气流平衡板的位置移动，使得p1≥p2即可。以防止PH段高NOx废气向TPH段窜风。
在本发明中，所述防窜风装置包括气流平衡板、移动平台、辊轮以及开槽。所述气流平衡板设置在链箅机的内部。所述移动平台设置在预热一段和预热二段外部下端的两侧。所述辊轮设置在移动平台底部。所述开槽开设在预热一段和预热二段外部上端的两侧。所述移动平台上还设置有固定座。所述固定座上设置有立柱。所述立柱的顶端穿过开槽后与气流平衡板的顶端相连接(立柱的顶端横向弯曲后穿过开槽与气流平衡板的顶端连接)。所述移动平台的外部还设置有移动电机。移动电机驱动移动平台在辊轮上进行移动。移动平台的移动带动固定座、立柱的移动进而带动气流平衡板在链箅机内(由PH段向TPH段移动)的移动。
进一步地，所述气流平衡板由外板和内板组成。所述外板为一个内部中空的板体。所述内板套接在外板的内腔中。所述内板还与升降电机相连。升降电机控制内板在外板内腔的竖直方向上进行移动。根据实际需要，调节内板的移动，进而改变气流平衡板的整体高度以满足不同高度的工况需求，防止窜风现象的发生。
在本发明中，所述内板的厚度为1-20cm，优选为2-15cm，更优选为3-10cm。所述外板的厚度(即为所述气流平衡板的整体厚度)为3-25cm，优选为5-20cm，更优选为8-15cm。其中外板的内腔的厚度大于内板的厚度(例如外板内腔的厚度比内板的厚度大0.5cm、1cm、1.5cm、2cm等，可根据实际工况需求进行选择)。
在本发明中，通过在预热一段内设置有第一温度检测计实时检测预热一段内的气体温度为c1，K。在预热二段内设置有第二温度检测计实时检测预热二段内的气体温度为c2，K。在第七管道上还设置有第一流量检测计实时检测输送至预热一段内的气体流量为q1，Nm 3/h。在第一管道上设置有第二流量检测计实时检测输送至预热二段内的气体流量为q2，Nm 3/h。则可以计算得出输送至预热一段内的气体质量为m1，g：
m1＝ρ*q1*t...式I。
进一步地，输送至预热二段内的气体质量为m2，g：
m2＝ρ*q2*t...式II。
在式I和式II中，ρ为气体平均密度，g/m 3。t为气体输送时间，h。
根据理想气体状态方程(pV＝nRT＝mRT/M)，可以得：
p1*v1＝ρ*q1*t*R*c1/M...式III。
p2*v2＝ρ*q2*t*R*c2/M...式IV。
在式III和式IV中，v1为预热一段的容积，m 3。v2为预热二段的容积，m 3。R为气体常量，J/(mol·K)。M为气体平均摩尔质量，g/mol。
作为优选，设定预热一段的长度为a1，宽度为b1，高度为h1，单位均为m。设定预热二段的长度为a2，宽度为b2，高度为h2，单位均为m。则：
v1＝k1*a1*b1*h1...式V。
v2＝k2*a2*b2*h2...式VI。
在式V和式VI中，所述k1为预热一段的容积修正比值。k2为预热二段的容积修正比值。
在本发明中，当预热一段或预热二段的内腔构形为规则的矩形体时：k1＝k2＝1。而当预热一段或预热二段的内腔构形为非规则的矩形体时，为了修正体积计算公式(长×宽×高)的误差值，因此引入修正值k1和k2，使得计算获得的体积最接近实际体积。一般地，针对同一台链箅机而言，k1和k2的值为一个固定的常数。
进一步地，将式V代入式III，得：
p1＝ρ*q1*t*R*c1/(M*k1*a1*b1*h1)...式VII。
进一步地，将式VI代入式IV，得：
p2＝ρ*q2*t*R*c2/(M*k2*a2*b2*h2)...式VII。
当p1＜p2时，此时需要移动气流平衡板(气流平衡板初始位置为预热一段和预热二段的交界处)使得p1≥p2，设定气流平衡板向预热一段方向的水平移动量为△a，m。则：
Z＝p1/p2＝[q1*c1*k2*(a2-△a)*b2*h2]/[q2*c2*k1*(a1+△a)*b1*h1]...式VIII。
当Z＝1时(即p1＝p2)，则气流平衡板的最小应移动量△a min为：
Figure PCTCN2021075587-appb-000002
通过调节气流平衡板的水平移动量△a大于等于式IX的计算值△a min，m，进而使得Z≥1，即p1≥p2。
在本发明中，调节所述气流平衡板水平位移为△a时为分步调节，调整次数设为N，则：
N＝丨(p2-p1)/(0.05*p1)丨...式X。
当所述气流平衡板的所需水平位移为△a时，则气流平衡板的移动次数是式X的计算值N。
需要说明的是，这里计算出来的△a不能简单粗暴的一下调整到位，而是需要缓慢调整，并在调整过程中不断检测实时参数的变化情况，并及时修正，避免因调整步幅过大导致生产波动猛烈而影响产质量指标。这里就需要设定调整步长：L＝△a/N(以△a取值为△a min为例)，分N次进行调整，N＝(p2-p1)/(0.05*p1)，N取整。进一步地，上述N的确定为较佳计算方式，但不是仅限于此方法，原则上N值的确定需要根据调整紧迫程度(p1比p2少得越多，调整次数应该越少，因为要尽快减少压力差)。但是每调整一次步长后需进行一次新的压力检测，如果没有达到目标(p1≥p2)才继续下去。如果达到目标，则 停止调节。
进一步地，在预热一段内还设置有烟气分析仪实时检测预热一段内的NOx的含量小于等于40mg/m 3。或者，根据国家超低排放标准，NOx最终排放的浓度低于50mg/m 3即可。
与现有技术相比较，本发明具有如下有益技术效果：
1、本发明所述系统通过在链箅机PH段和TPH段之间增设可移动式防窜风装置，利用防窜风装置位置变化来主要控制TPH段的气压大于等于PH段的气压，防止PH段高NOx废气向TPH段串风，使得TPH段烟气中NOx含量升高。有效降低污染物的直接排放。
2、本发明所述的链箅机风流系统只需对PH段废气(约1/3)进行SNCR+SCR脱硝处理即可满足球团NOx超低排放要求，投资和运行成本大大减少；同时可将TPH段靠近PH段的部分风箱选择性的并入PH段，间接延长了球团高温预热时间，起到改善预热球强度的作用。
3、本发明所述系统结构简单，易操作，成本投入低，控风减排效果显著，具有较强的应用前景和较大的经济效益。
4、本发明所述的风流控制方法简单精确，控制流程短，通过实时数据监测，在极短的时间内即可做出反应，同时通过气流平衡板边移动变计算的方式实现一个动态的微调，不仅使得气流平衡板的调节更加科学合理，而且还能够有效避免因调整步幅过大导致生产波动猛烈而影响产质量指标的问题发生。
附图说明
图1为本发明链箅机预热段防窜风系统的结构示意图。
图2为本发明链箅机预热段防窜风系统具有检测机制的结构示意图。
图3为本发明防窜风装置的结构示意图。
图4为本发明气流平衡板的结构示意图。
图5为本发明防窜风装置俯视结构图。
图6为本发明风流控制调节方法流程图。
附图标记：1：链箅机；2：回转窑；3：防窜风装置；4：氨剂脱硝装置；5：SCR脱硝装置；6：除尘装置；7：环冷机；UDD：鼓风干燥段；DDD：抽风干燥段；TPH：预热一段；PH：预热二段；301：气流平衡板；30101：外板；30102：内板；30103：升降电机；302：移动平台；30201：固定座；30202：立柱；30203：移动电机；303：辊轮；304：开槽；401：第一喷洒器；402：第二喷洒器；403：氨剂储存罐；C1：环冷一段；C2：环冷二段；C3：环冷三段；L1：第一管道；L2：第二管道；L3：第三管道；L4：第四管道；L5：第五管道；L6：第六管道；L7：第七管道；L8：第八管道；L9：第九管道；L10：第十管道；P1：第一压力检测计；P2：第二压力检测计；T1：第一温度检测计；T2：第二温度检测计；Q1：第一流量检测计；Q2：第二流量检测计；Y：烟气分析仪。
具体实施方式
下面对本发明的技术方案进行举例说明，本发明请求保护的范围包括但不限于以下实施例。
根据本发明的第一种实施方案，提供一种链箅机预热段防窜风系统，该系统包括链箅机1和回转窑2。根据物料的走向，所述链箅机1依次设有鼓风干燥段UDD、抽风干燥段 DDD、预热一段TPH和预热二段PH。所述预热二段PH通过第一管道L1与回转窑2的烟气出口相连通。所述预热一段TPH和预热二段PH之间设置有防窜风装置3。
作为优选，所述防窜风装置3包括气流平衡板301、移动平台302、辊轮303以及开槽304。所述气流平衡板301设置在链箅机1的内部。所述移动平台302设置在预热一段TPH和预热二段PH外部下端的两侧。所述辊轮303设置在移动平台302底部。所述开槽304开设在预热一段TPH和预热二段PH外部上端的两侧。所述移动平台302上还设置有固定座30201。所述固定座30201上设置有立柱30202。所述立柱30202的顶端穿过开槽304后与气流平衡板301的顶端相连接。所述移动平台302的外部还设置有移动电机30203。移动电机30203驱动移动平台302在辊轮303上进行移动。移动平台302的移动带动固定座30201、立柱30202的移动进而带动气流平衡板301在链箅机1内的移动。
作为优选，所述气流平衡板301由外板30101和内板30102组成。所述外板30101为一个内部中空的板体。所述内板30102套接在外板30101的内腔中。所述内板30102还与升降电机30103相连。升降电机30103控制内板30102在外板30101内腔的竖直方向上进行移动。
作为优选，该系统还包括有氨剂脱硝装置4。所述氨剂脱硝装置4设置在预热二段PH和/或第一管道L1内。
作为优选，所述氨剂脱硝装置4包括有第一喷洒器401、第二喷洒器402和氨剂储存罐403。所述第一喷洒器401设置在预热二段PH内。所述第二喷洒器402设置在第一管道L1内。所述氨剂储存罐403通过第二管道L2与第一喷洒器401相连接。所述第二管道L2上分出第三管道L3与第二喷洒器402相连接。
作为优选，该系统还包括有SCR脱硝装置5和除尘装置6。所述预热二段PH的出风口通过第四管道L4连通至抽风干燥段DDD的进风口。所述抽风干燥段DDD的出风口通过第五管道L5连通至烟囱。所述SCR脱硝装置5设置在第四管道L4上。所述除尘装置6设置在第五管道L5上。
作为优选，该系统还包括有环冷机7。所述环冷机7依次设有环冷一段C1、环冷二段C2以及环冷三段C3。所述环冷一段C1的出风口通过第六管道L6连通至回转窑2的进风口。所述环冷二段C2的出风口通过第七管道L7连通至预热一段TPH的进风口。所述环冷三段C3的出风口通过第八管道L8连通至鼓风干燥段UDD的进风口。所述预热一段TPH的出风口通过第九管道L9连通至第五管道L5。所述鼓风干燥段UDD的出风口通过第十管道L10连通至烟囱。
作为优选，该系统还包括有第一压力检测计P1、第二压力检测计P2、第一温度检测计T1、第二温度检测计T2、第一流量检测计Q1、第二流量检测计Q2以及烟气分析仪Y。所述第一压力检测计P1、第一温度检测计T1和烟气分析仪Y设置在预热一段TPH内。所述第二压力检测计P2和第二温度检测计T2设置在预热二段PH内。所述第一流量检测计Q1设置在第七管道L7上。所述第二流量检测计Q2设置在第一管道L1上。
根据本发明的第二种实施方案，提供一种链箅机预热段风流控制方法或使用第一种实施方案所述链箅机预热段防窜风系统进行风流控制的方法，该方法包括如下步骤：
1)根据物料的走向，生球进入链箅机1，依次经过鼓风干燥段UDD、抽风干燥段DDD、预热一段TPH和预热二段PH后输送至回转窑2内进行氧化焙烧。氧化焙烧完成后的氧化 球团矿输送至环冷机7进行冷却。
2)根据热风的流向，环冷一段C1排出的热风经由第六管道L6输送至回转窑2内，然后再经第一管道L1输送至预热二段PH内。环冷二段C2排出的热风经由第七管道L7输送至预热一段TPH内。
3)调节设置在预热一段TPH和预热二段PH之间的防窜风装置3的水平位置，使得预热一段TPH内的压力大于或等于预热二段PH内的压力。
4)预热一段TPH内的热风最后经由第九管道L9排出。预热二段PH内的热风最后经由第四管道L4排出。
优选地，该方法中，在步骤3)中，所述调节设置在预热一段TPH和预热二段PH之间的防窜风装置3的水平位置，包括：
通过移动电机30203驱动移动平台302在辊轮303上进行移动；移动平台302的移动带动固定座30201、立柱30202的移动进而带动气流平衡板301在链箅机1内的移动；
通过升降电机30103控制所述气流平衡板301的内板30102在所述气流平衡板301的外板30101内腔的竖直方向上进行移动。
作为优选，该方法还包括：在预热一段TPH内设置有第一压力检测计P1实时检测预热一段TPH内的气压为p1，Pa。还设置有第一温度检测计T1实时检测预热一段TPH内的气体温度为c1，K。
作为优选，在预热二段PH内设置有第二压力检测计P2实时检测预热二段PH内的气压为p2，Pa。还设置有第二温度检测计T2实时检测预热二段PH内的气体温度为c2，K。
作为优选，在第七管道L7上还设置有第一流量检测计Q1实时检测输送至预热一段TPH内的气体流量为q1，Nm 3/h。在第一管道L1上设置有第二流量检测计Q2实时检测输送至预热二段PH内的气体流量为q2，Nm 3/h。则输送至预热一段TPH内的气体质量为m1，g：
m1＝ρ*q1*t...式I。
输送至预热二段TPH内的气体质量为m2，g：
m2＝ρ*q2*t...式II。
在式I和式II中，ρ为气体平均密度，g/m 3。t为气体输送时间，h。
根据理想气体状态方程，得：
p1*v1＝ρ*q1*t*R*c1/M...式III。
P2*v2＝ρ*q2*t*R*c2/M...式IV。
在式III和式IV中，v1为预热一段TPH的容积，m 3。v2为预热二段PH的容积，m 3。R为气体常量，J/(mol·K)。M为气体平均摩尔质量，g/mol。
作为优选，设定预热一段TPH的长度为a1，宽度为b1，高度为h1，单位均为m。设定预热二段PH的长度为a2，宽度为b2，高度为h2，单位均为m。则：
v1＝k1*a1*b1*h1...式V。
V2＝k2*a2*b2*h2...式VI。
在式V和式VI中，所述k1为预热一段TPH的容积修正比值。k2为预热二段PH的容积修正比值。
将式V代入式III，得：
p1＝ρ*q1*t*R*c1/(M*k1*a1*b1*h1)...式VII。
将式VI代入式IV，得：
P2＝ρ*q2*t*R*c2/(M*k2*a2*b2*h2)...式VII。
设定气流平衡板301向预热一段TPH方向的水平移动量为△a，m。则：
Z＝p1/p2＝[q1*c1*k2*(a2-△a)*b2*h2]/[q2*c2*k1*(a1+△a)*b1*h1]...式VIII。
当Z＝1时，则气流平衡板301的最小应移动量△a min为：
Figure PCTCN2021075587-appb-000003
通过调节气流平衡板301的水平移动量△a大于等于式IX的计算值△a min，m，进而使得Z≥1，即p1≥p2。
作为优选，调节所述气流平衡板301水平位移为△a时为分步调节，调整次数设为N，则：
N＝(p2-p1)/(0.05*p1)...式X。
当所述气流平衡板301的所需水平位移为△a时，则气流平衡板301的移动次数是式X的计算值N。
作为优选，在预热一段TPH内还设置有烟气分析仪Y实时检测预热一段TPH内的NOx的含量小于等于40mg/m 3。
实施例1
如图1所示，一种链箅机预热段防窜风系统，该系统包括链箅机1和回转窑2。根据物料的走向，所述链箅机1依次设有鼓风干燥段UDD、抽风干燥段DDD、预热一段TPH和预热二段PH。所述预热二段PH通过第一管道L1与回转窑2的烟气出口相连通。所述预热一段TPH和预热二段PH之间设置有防窜风装置3。
实施例2
重复实施例1，在实施例1的基础上所述防窜风装置3包括气流平衡板301、移动平台302、辊轮303以及开槽304。所述气流平衡板301设置在链箅机1的内部。所述移动平台302设置在预热一段TPH和预热二段PH外部下端的两侧。所述辊轮303设置在移动平台302底部。所述开槽304开设在预热一段TPH和预热二段PH外部上端的两侧。所述移动平台302上还设置有固定座30201。所述固定座30201上设置有立柱30202。所述立柱30202的顶端穿过开槽304后与气流平衡板301的顶端相连接。所述移动平台302的外部还设置有移动电机30203。移动电机30203驱动移动平台302在辊轮303上进行移动。移动平台302的移动带动固定座30201、立柱30202的移动进而带动气流平衡板301在链箅机1内的移动。
实施例3
重复实施例2，在实施例2的基础上所述气流平衡板301由外板30101和内板30102组成。所述外板30101为一个内部中空的板体。所述内板30102套接在外板30101的内腔中。所述内板30102还与升降电机30103相连。升降电机30103控制内板30102在外板30101内腔的竖直方向上进行移动。
实施例4
重复实施例3，在实施例3的基础上该系统还包括有氨剂脱硝装置4。所述氨剂脱硝 装置4设置在预热二段PH和/或第一管道L1内。
实施例5
重复实施例4，在实施例4的基础上所述氨剂脱硝装置4包括有第一喷洒器401、第二喷洒器402和氨剂储存罐403。所述第一喷洒器401设置在预热二段PH内。所述第二喷洒器402设置在第一管道L1内。所述氨剂储存罐403通过第二管道L2与第一喷洒器401相连接。所述第二管道L2上分出第三管道L3与第二喷洒器402相连接。
实施例6
重复实施例5，在实施例5的基础上该系统还包括有SCR脱硝装置5和除尘装置6。所述预热二段PH的出风口通过第四管道L4连通至抽风干燥段DDD的进风口。所述抽风干燥段DDD的出风口通过第五管道L5连通至烟囱。所述SCR脱硝装置5设置在第四管道L4上。所述除尘装置6设置在第五管道L5上。
实施例7
重复实施例6，在实施例6的基础上该系统还包括有环冷机7。所述环冷机7依次设有环冷一段C1、环冷二段C2以及环冷三段C3。所述环冷一段C1的出风口通过第六管道L6连通至回转窑2的进风口。所述环冷二段C2的出风口通过第七管道L7连通至预热一段TPH的进风口。所述环冷三段C3的出风口通过第八管道L8连通至鼓风干燥段UDD的进风口。所述预热一段TPH的出风口通过第九管道L9连通至第五管道L5。所述鼓风干燥段UDD的出风口通过第十管道L10连通至烟囱。
实施例8
重复实施例7，在实施例7的基础上该系统还包括有第一压力检测计P1、第二压力检测计P2、第一温度检测计T1、第二温度检测计T2、第一流量检测计Q1、第二流量检测计Q2以及烟气分析仪Y。所述第一压力检测计P1、第一温度检测计T1和烟气分析仪Y设置在预热一段TPH内。所述第二压力检测计P2和第二温度检测计T2设置在预热二段PH内。所述第一流量检测计Q1设置在第七管道L7上。所述第二流量检测计Q2设置在第一管道L1上。
方法实施例
设定链箅机预热一段TPH的长度为a1为12m，宽度为b1为4.5m，高度为h1为3m。设定预热二段PH的长度为a2为15m，宽度为b2为4.5m，高度为h2为3m。预热一段TPH的容积修正比值k1为1。预热二段PH的容积修正比值k2为1(即链箅机预热一段TPH和预热二段PH均为矩形)。当气流平衡板301处于初始位置时(即预热一段TPH和预热二段PH的交界处)：
预热一段TPH的容积为：v1＝1×12×4.5×3＝162m 3。
预热二段PH的容积为：v2＝1×15×4.5×3＝202.5m 3。
检测到输送至预热一段TPH内的气体流量为q1为100Nm 3/h。检测到输送至预热二段PH内的气体流量为q2为150Nm 3/h。检测到预热一段TPH内的气体温度为c1为858.15K。检测到预热二段PH内的气体温度为c2为1250.15K。
在系统运行过程中，若检测到预热一段TPH内的气压p1为-900Pa；检测到预热二段PH内的气压P2为-400Pa。则根据式VIII和式IX进行如下计算：
Z＝p1/p2＝[q1*c1*k2*(a2-△a)*b2*h2]/[q2*c2*k1*(a1+△a)*b1*h1]...式VIII。
当Z＝1时，则气流平衡板301的最小应移动量△a min为：
Figure PCTCN2021075587-appb-000004
即：
△a min＝(12×4.5×3×1250.15×150-15×4.5×3×858.15×100)/(150×1250.15×4.5×3+100×858.15×4.5×3)＝9.47
根据式X计算所述气流平衡板301水平位移为△a＝△a min时所需调整次数N：
N＝(p2-p1)/(0.05*p1)...式X。
即：
N＝(-400+900)/(0.05×-900)＝11.11。
分步调节气流平衡板301时，单次调节步长为STEP：STEP＝△ amin/N＝9.47/11.11＝0.85，根据STEP的计算值对气流平衡板301进行调节(从PH段向TPH端调节)，单次调节步长为0.85m，完成调节后检测p1和p2，若p1≥p2，则完成气流平衡板301的调节；若p1＜p2，则继续按步长STEP为0.85m对气流平衡板301进行调节，直至p1≥p2。

Claims (11)

  1. 一种链箅机预热段防窜风系统，其特征在于：该系统包括链箅机(1)和回转窑(2)；根据物料的走向，所述链箅机(1)依次设有鼓风干燥段(UDD)、抽风干燥段(DDD)、预热一段(TPH)和预热二段(PH)；所述预热二段(PH)通过第一管道(L1)与回转窑(2)的烟气出口相连通；所述预热一段(TPH)和预热二段(PH)之间设置有防窜风装置(3)。
  2. 根据权利要求1所述的系统，其特征在于：所述防窜风装置(3)包括气流平衡板(301)、移动平台(302)、辊轮(303)以及开槽(304)；所述气流平衡板(301)设置在链箅机(1)的内部；所述移动平台(302)设置在预热一段(TPH)和预热二段(PH)外部下端的两侧；所述辊轮(303)设置在移动平台(302)底部；所述开槽(304)开设在预热一段(TPH)和预热二段(PH)外部上端的两侧；所述移动平台(302)上还设置有固定座(30201)；所述固定座(30201)上设置有立柱(30202)；所述立柱(30202)的顶端穿过开槽(304)后与气流平衡板(301)的顶端相连接；所述移动平台(302)的外部还设置有移动电机(30203)；移动电机(30203)驱动移动平台(302)在辊轮(303)上进行移动；移动平台(302)的移动带动固定座(30201)、立柱(30202)的移动进而带动气流平衡板(301)在链箅机(1)内的移动；
    所述气流平衡板(301)由外板(30101)和内板(30102)组成；所述外板(30101)为一个内部中空的板体；所述内板(30102)套接在外板(30101)的内腔中；所述内板(30102)还与升降电机(30103)相连；升降电机(30103)控制内板(30102)在外板(30101)内腔的竖直方向上进行移动。
  3. 根据权利要求1或2所述的系统，其特征在于：该系统还包括有氨剂脱硝装置(4)；所述氨剂脱硝装置(4)设置在预热二段(PH)和/或第一管道(L1)内；
    所述氨剂脱硝装置(4)包括有第一喷洒器(401)、第二喷洒器(402)和氨剂储存罐(403)；所述第一喷洒器(401)设置在预热二段(PH)内；所述第二喷洒器(402)设置在第一管道(L1)内；所述氨剂储存罐(403)通过第二管道(L2)与第一喷洒器(401)相连接；所述第二管道(L2)上分出第三管道(L3)与第二喷洒器(402)相连接。
  4. 根据权利要求1-3中任一项所述的系统，其特征在于：该系统还包括有SCR脱硝装置(5)和除尘装置(6)；所述预热二段(PH)的出风口通过第四管道(L4)连通至抽风干燥段(DDD)的进风口；所述抽风干燥段(DDD)的出风口通过第五管道(L5)连通至烟囱；所述SCR脱硝装置(5)设置在第四管道(L4)上；所述除尘装置(6)设置在第五管道(L5)上。
  5. 根据权利要求1-4中任一项所述的系统，其特征在于：该系统还包括有环冷机(7)；所述环冷机(7)依次设有环冷一段(C1)、环冷二段(C2)以及环冷三段(C3)；所述环冷一段(C1)的出风口通过第六管道(L6)连通至回转窑(2)的进风口；所述环冷二段(C2)的出风口通过第七管道(L7)连通至预热一段(TPH)的进风口；所述环冷三段(C3)的出风口通过第八管道(L8)连通至鼓风干燥段(UDD)的进风口；所述预热一段(TPH)的出风口通过第九管道(L9)连通至第五管道(L5)；所述鼓风干燥段(UDD)的出风口通过第十管道(L10)连通至烟囱。
  6. 根据权利要求5所述的系统，其特征在于：该系统还包括有第一压力检测计(P1)、 第二压力检测计(P2)、第一温度检测计(T1)、第二温度检测计(T2)、第一流量检测计(Q1)、第二流量检测计(Q2)以及烟气分析仪(Y)；所述第一压力检测计(P1)、第一温度检测计(T1)和烟气分析仪(Y)设置在预热一段(TPH)内；所述第二压力检测计(P2)和第二温度检测计(T2)设置在预热二段(PH)内；所述第一流量检测计(Q1)设置在第七管道(L7)上；所述第二流量检测计(Q2)设置在第一管道(L1)上。
  7. 一种链箅机预热段风流控制方法或使用如权利要求1-6中任一项所述链箅机预热段防窜风系统进行风流控制的方法，其特征在于：所述方法包括如下步骤：
    1)根据物料的走向，生球进入链箅机(1)，依次经过鼓风干燥段(UDD)、抽风干燥段(DDD)、预热一段(TPH)和预热二段(PH)后输送至回转窑(2)内进行氧化焙烧；氧化焙烧完成后的氧化球团矿输送至环冷机(7)进行冷却；
    2)根据热风的流向，环冷一段(C1)排出的热风经由第六管道(L6)输送至回转窑(2)内，然后再经第一管道(L1)输送至预热二段(PH)内；环冷二段(C2)排出的热风经由第七管道(L7)输送至预热一段(TPH)内；
    3)调节设置在预热一段(TPH)和预热二段(PH)之间的防窜风装置(3)的水平位置，使得预热一段(TPH)内的压力大于或等于预热二段(PH)内的压力；
    4)预热一段(TPH)内的热风最后经由第九管道(L9)排出；预热二段(PH)内的热风最后经由第四管道(L4)排出。
  8. 根据权利要求7所述的方法，其特征在于，所述调节设置在预热一段(TPH)和预热二段(PH)之间的防窜风装置(3)的水平位置，包括：
    通过移动电机(30203)驱动移动平台(302)在辊轮(303)上进行移动；移动平台(302)的移动带动固定座(30201)、立柱(30202)的移动进而带动气流平衡板(301)在链箅机(1)内的移动；
    通过升降电机(30103)控制所述气流平衡板(301)的内板(30102)在所述气流平衡板(301)的外板(30101)内腔的竖直方向上进行移动。
  9. 根据权利要求8所述的方法，其特征在于：该方法还包括：在预热一段(TPH)内设置有第一压力检测计(P1)实时检测预热一段(TPH)内的气压为p1，Pa；还设置有第一温度检测计(T1)实时检测预热一段(TPH)内的气体温度为c1，K；
    在预热二段(PH)内设置有第二压力检测计(P2)实时检测预热二段(PH)内的气压为p2，Pa；还设置有第二温度检测计(T2)实时检测预热二段(PH)内的气体温度为c2，K；
    在第七管道(L7)上还设置有第一流量检测计(Q1)实时检测输送至预热一段(TPH)内的气体流量为q1，Nm 3/h；在第一管道(L1)上设置有第二流量检测计(Q2)实时检测输送至预热二段(PH)内的气体流量为q2，Nm 3/h；则输送至预热一段(TPH)内的气体质量为m1，g：输送至预热二段(PH)内的气体质量为m2，g：
    根据理想气体状态方程，得：
    p1*v1＝ρ*q1*t*R*c1/M；
    p2*v2＝ρ*q2*t*R*c2/M；
    其中，ρ为气体平均密度，g/m 3；t为气体输送时间，h；v1为预热一段(TPH)的容积，m 3；v2为预热二段(PH)的容积，m 3；R为气体常量，J/(mol·K)；M为气体平均摩 尔质量，g/mol。
  10. 根据权利要求9所述的方法，其特征在于：设定预热一段(TPH)的长度为a1，宽度为b1，高度为h1，单位均为m；设定预热二段(PH)的长度为a2，宽度为b2，高度为h2，单位均为m；则：
    v1＝k1*a1*b1*h1；
    v2＝k2*a2*b2*h2；
    其中，所述k1为预热一段(TPH)的容积修正比值；k2为预热二段(PH)的容积修正比值；
    将预热一段(TPH)的容积v1代入理想气体状态方程，所述预热一段(TPH)内的气压由以下公式获得：
    p1＝ρ*q1*t*R*c1/(M*k1*a1*b1*h1)；
    将预热二段(PH)的容积v2代入理想气体状态方程，所述预热二段(PH)内的气压由以下公式获得：
    p2＝ρ*q2*t*R*c2/(M*k2*a2*b2*h2)；
    设定气流平衡板(301)向预热一段(TPH)方向的水平移动量为△a，m；则所述预热一段(TPH)内的气压与预热二段(PH)内的气压之比Z由以下公式获得：
    Z＝p1/p2＝[q1*c1*k2*(a2-△a)*b2*h2]/[q2*c2*k1*(a1+△a)*b1*h1]；
    当Z＝1时，则气流平衡板(301)的最小应移动量△a min为：
    Figure PCTCN2021075587-appb-100001
    通过调节气流平衡板(301)的水平移动量△a大于等于最小应移动量△a min的计算值，m，进而使得Z≥1，即p1≥p2。
  11. 根据权利要求10所述的方法，其特征在于：调节所述气流平衡板(301)水平位移为△a时为分步调节，调整次数设为N，则：
    N＝丨(p2-p1)/(0.05*p1)丨；
    当所述气流平衡板(301)的所需水平位移为△a时，则气流平衡板(301)的移动次数是调整次数N的计算值；
    在预热一段(TPH)内还设置有烟气分析仪(Y)实时检测预热一段(TPH)内的NOx的含量是否小于等于40mg/m 3。
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