WO2024056068A1 - 一种喷射直火预热系统 - Google Patents

一种喷射直火预热系统 Download PDF

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Publication number
WO2024056068A1
WO2024056068A1 PCT/CN2023/119085 CN2023119085W WO2024056068A1 WO 2024056068 A1 WO2024056068 A1 WO 2024056068A1 CN 2023119085 W CN2023119085 W CN 2023119085W WO 2024056068 A1 WO2024056068 A1 WO 2024056068A1
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WO
WIPO (PCT)
Prior art keywords
direct
furnace
exhaust gas
fired
chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2023/119085
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English (en)
French (fr)
Inventor
张理扬
李俊
王骏飞
万照堂
王彦辉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Baoshan Iron and Steel Co Ltd
Original Assignee
Baoshan Iron and Steel Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Baoshan Iron and Steel Co Ltd filed Critical Baoshan Iron and Steel Co Ltd
Priority to EP23864797.8A priority Critical patent/EP4589031A4/en
Priority to US19/110,174 priority patent/US20260085374A1/en
Priority to KR1020257011680A priority patent/KR20250065891A/ko
Priority to JP2025515820A priority patent/JP2025534244A/ja
Publication of WO2024056068A1 publication Critical patent/WO2024056068A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/561—Continuous furnaces for strip or wire with a controlled atmosphere or vacuum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/005—Furnaces in which the charge is moving up or down
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/34—Methods of heating
    • C21D1/52—Methods of heating with flames
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/767—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material with forced gas circulation; Reheating thereof
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/562—Details
    • C21D9/565—Sealing arrangements
    • 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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path
    • 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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/28—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity for treating continuous lengths of work
    • 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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B9/3005—Details, accessories or equipment specially adapted for furnaces of these types arrangements for circulating gases
    • 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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B9/36—Arrangements of heating 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
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/10—Arrangements for using waste heat
    • 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
    • F27D17/10—Arrangements for using waste heat
    • F27D17/15—Arrangements for using waste heat using boilers
    • 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
    • F27D17/10—Arrangements for using waste heat
    • F27D17/17—Arrangements for using waste heat for preheating fluids, e.g. air or 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
    • F27D17/10—Arrangements for using waste heat
    • F27D17/18—Arrangements for using waste heat for preheating solid materials
    • 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
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D3/0024—Charging; Discharging; Manipulation of charge of metallic workpieces
    • 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
    • F27D7/04—Circulating atmospheres by mechanical means
    • 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
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0073—Seals
    • F27D99/0075—Gas curtain seals
    • 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
    • F27D3/00—Charging; Discharging; Manipulation of charge
    • F27D2003/0034—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities
    • F27D2003/0042—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities comprising roller trains
    • 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
    • F27D7/04—Circulating atmospheres by mechanical means
    • F27D2007/045—Fans
    • 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
    • F27D2019/0006—Monitoring the characteristics (composition, quantities, temperature, pressure) of at least one of the gases of the kiln atmosphere and using it as a controlling value
    • F27D2019/0018—Monitoring the temperature of the atmosphere of the kiln
    • F27D2019/0021—Monitoring the temperature of the exhaust gases

Definitions

  • the invention relates to the technical field of continuous heat treatment of strip steel, and in particular to a spray direct fire preheating system.
  • Continuous annealing has largely replaced bell annealing due to its advantages such as high production efficiency and good strip surface quality.
  • the main equipment used for continuous annealing is the continuous annealing furnace.
  • the vertical annealing furnace is the preferred annealing furnace type for large continuous annealing units or hot-dip galvanizing units.
  • vertical annealing furnaces include preheating section, heating section, soaking section, slow cooling section, rapid cooling section and other parts.
  • the heating section uses a direct fire heating section, the temperature of the exhaust gas from direct fire combustion can reach over 1000°C.
  • the direct-fired combustion exhaust gas is usually directed to the preheating section with an exhaust gas fan (the corresponding equipment is called a preheating furnace).
  • the preheating section the strip steel runs upward, and the direct-fired combustion exhaust gas is directed upwards.
  • the combustion exhaust gas runs downward.
  • the direct fire combustion exhaust gas contacts the strip steel and preheats the steel strip.
  • the waste gas after preheating the steel is discharged to the outside of the furnace through pipes, and then discharged after secondary utilization (usually using a waste heat boiler to recover heat).
  • the exhaust gas emission temperature of direct fire combustion after preheating the steel is still relatively high, usually exceeding 800°C, and sometimes exceeding 850°C. When it exceeds 850°C, it is usually necessary to mix in cold air to control the exhaust gas emission temperature to 850°C and below. Perform secondary offline utilization. The higher the exhaust gas temperature, the greater the heat energy loss. It can be seen that with this method, the primary online utilization rate of thermal energy is low, and the steam or hot water generated by the secondary offline utilization is often not fully consumed by the unit, so it will cause difficulties in energy balance in the region.
  • the direct-fired combustion exhaust gas directly contacts the strip steel and the contact time is long, in addition, the excess gas in the direct-fired combustion exhaust gas needs to be recombusted in the preheating section.
  • the secondary combustion flame is often an oxidizing flame, which inevitably limits
  • the preheating temperature of the strip should be increased. Otherwise, an excessively thick oxide layer will easily form on the surface of the strip, causing surface quality problems.
  • the preheating temperature of the strip can only be preheated to about 250°C, and the preheating effect is poor.
  • the corresponding direct fire heating has limited heating capacity and the heating temperature cannot be too high.
  • the strip can only be heated to 750°C and below. If the heating temperature is further increased, the strip is prone to cracking. Severe oxidation.
  • the purpose of this invention is to design a spray direct-fire preheating system that can quickly preheat the strip temperature to at least 350°C and above, and cooperate with the direct-fire heating furnace to quickly heat the strip temperature to above 750°C; at the same time, the strip temperature can be quickly preheated to at least 350°C or above.
  • the waste heat of the fire combustion exhaust gas is fully utilized, and the direct fire combustion exhaust gas can be prevented from directly contacting the strip steel for a long time in the preheating furnace, thereby avoiding the formation of an excessively thick oxide layer on the surface of the strip steel.
  • a preheating furnace which includes:
  • the upper side wall of the furnace body is provided with at least two connection holes, which are arranged symmetrically left and right, and are connected to the through holes in the upper part of the direct furnace shell through communication pipes; the top of the furnace body is provided with a roller chamber corresponding to the top of the direct furnace.
  • the furnace throat through which the strip steel passes; the strip steel inlet and the corresponding sealing device and the steering roller are provided at the bottom of the furnace body; the upper part of the furnace body is provided with an upper partition with holes to form an upper gas collecting chamber for direct-fired exhaust gas; the upper part of the direct-fired exhaust gas There is a direct-fired combustion exhaust gas secondary combustion chamber below the gas collecting chamber, and at least one open flame burner is installed in the direct-fired combustion exhaust gas secondary combustion chamber; a lower partition with holes is installed in the lower part of the furnace body to form a lower gas collection of direct-fired exhaust gases. room, and is connected to an exhaust fan through an exhaust pipe;
  • each heat exchange and jet air box unit includes,
  • the air box body has a number of heat exchange tubes vertically arranged inside it, and a number of nozzles are arranged on one side of the air box body relative to the belt passage; an exhaust gas secondary mixing chamber connected to the heat exchange tubes is arranged between the upper and lower air box bodies. ;
  • Circulation fan the port of its inlet pipe is arranged in the belt passage, and the port of its outlet pipe is located in the wind box;
  • a number of sealing devices for the steel strip to pass through are respectively provided at the upper and lower ports of the strip passage and at the strip holes of the upper and lower partitions.
  • a combustion exhaust gas thermometer is also provided in the direct-fired combustion exhaust gas secondary combustion chamber to measure the actual temperature of the combustion exhaust gas that will enter the heat exchange and injection wind box unit after the secondary combustion.
  • the thermometer detects that the exhaust temperature at the top of the heat exchange and jet air box unit is too high, the exhaust gas temperature can be reduced by adjusting the combustion air volume of the open flame burner (the open flame burner comes with a long open flame ignition burner, and the ignition burner The amount of air does not participate in the adjustment, thereby maintaining the stability of the ignition burner and ensuring that the remaining gas in the exhaust gas can be recombusted), thus ensuring the service life of the heat exchange and jet air box unit, especially its circulation fan.
  • the sealing device is a nitrogen sealing structure, using a nitrogen sealing chamber with a nitrogen injection pipe installed on it.
  • the exhaust gas discharge pipe is connected to the waste heat boiler and the chimney.
  • a control valve is provided on the exhaust gas discharge pipe for rapid adjustment of the exhaust gas furnace pressure to better maintain furnace pressure stability.
  • nitrogen and hydrogen protective gas is introduced into the wind box.
  • the preheating furnace of the present invention can be used to preheat strip steel by utilizing the heat of direct-fired combustion exhaust gas (the temperature of which can reach over 1000°C).
  • the strip runs upward, and the exhaust gas of direct-fire combustion runs downward.
  • the exhaust gas of direct-fire combustion contacts the strip and preheats the steel.
  • the temperature of the strip steel can be quickly preheated to above 350°C.
  • connection hole provided on the upper side wall of the furnace body is used to communicate with the through hole in the upper part of the direct-fired furnace shell, and is used to receive the exhaust gas of direct-fired combustion;
  • the sealing device at the strip entrance at the bottom of the furnace body is connected to a nitrogen injection pipe.
  • the upper partition plate with perforations provided in the upper part of the furnace body forms an upper gas collecting chamber for direct-fired exhaust gas with the upper part of the furnace body.
  • the upper gas-collecting chamber for direct-fired exhaust gas is connected with the through hole in the upper part of the direct-fired furnace shell and is used to accommodate the direct-fired exhaust gas. Fire combustion exhaust gas and allow the exhaust gas to exchange heat with the strip;
  • the direct-fired combustion exhaust gas secondary combustion chamber provided below the direct-fired exhaust gas upper collecting chamber is used for secondary combustion of excess gas in the direct-fired combustion exhaust gas from the direct-fired exhaust gas upper collecting chamber. It is provided with at least one open-fired combustion chamber. Fire burner, and a sealing device is installed close to the strip in the secondary combustion chamber of the direct-fired combustion exhaust gas. The sealing device is connected to a nitrogen injection pipe. By injecting nitrogen, the direct-fired combustion exhaust gas can be reduced as much as possible from entering the belt passage to avoid direct fire.
  • the combustion exhaust gas is in direct contact with the strip; the sealing device is a nitrogen sealing chamber, and the nitrogen in the sealing chamber has a certain pressure to minimize the direct fire combustion exhaust gas from entering the belt threading channel;
  • the lower partition plate with perforations set in the lower part of the furnace body and the lower part of the furnace body form a direct-fired exhaust gas lower gas collecting chamber, which is used to collect the direct-fired combustion exhaust gas flowing down from the upper part and use the exhaust gas to exchange heat with the strip. ;
  • the direct-fired combustion exhaust gas in the direct-fired exhaust gas lower gas collecting chamber is discharged from the direct-fired exhaust gas lower gas collecting chamber through the exhaust gas discharge pipe connected to the exhaust gas fan;
  • the heat exchange and jet air box unit set in the furnace body is set between the direct-fired combustion exhaust gas secondary combustion chamber and the direct-fired exhaust gas lower gas collecting chamber. It is set on both sides of the belt passage along the height direction of the furnace body, and is used to pass down the heat exchange tube.
  • the direct-fire combustion exhaust gas heats the gas outside the heat exchange tube (usually nitrogen and hydrogen protective gas), and the heated gas is sprayed through the nozzle onto the strip passing through the strip passage, and the strip is pre-heated. Hot, squirt to wear
  • the gas in the belt channel is extracted by the circulating fan and then sent into the air box body again, where it exchanges heat with the direct combustion exhaust gas;
  • the direct-fired combustion exhaust gas descending through the heat exchange tube in the wind box body enters the exhaust gas secondary mixing chamber provided in the furnace body. After mixing, it enters the heat exchange tube of the lower wind box body again, and the above heat exchange process is repeated.
  • the invention also provides an injection direct fire preheating system, which includes: a direct fire furnace and a preheating furnace; wherein,
  • the direct-fired stove includes:
  • the furnace shell has a top roller chamber and a furnace bottom roller chamber respectively at its upper and lower ends; the top roller chamber and the furnace bottom roller chamber are respectively equipped with steering rollers; several direct-fire heating zones are set up along the height direction in the furnace shell.
  • Several direct-fire burners are provided; at least two through holes are provided on the upper side wall of the furnace shell, and they are arranged symmetrically left and right;
  • the preheating furnace includes:
  • the upper side wall of the furnace body is provided with at least two connection holes, which are arranged symmetrically left and right, and are connected to the through holes in the upper part of the furnace shell of the direct furnace through communication pipes;
  • the top of the furnace body is provided with a roller chamber corresponding to the top of the furnace , a furnace throat for strip steel to pass through;
  • the bottom of the furnace body is equipped with a strip steel inlet and a corresponding sealing device and a steering roller;
  • an upper partition with holes is provided in the upper part of the furnace body to form an upper gas collecting chamber for direct-fired exhaust gas;
  • direct-fired A direct-fired combustion exhaust gas secondary combustion chamber is provided below the upper exhaust gas collection chamber, and at least one open flame burner is installed in the direct-fired combustion exhaust gas secondary combustion chamber;
  • a lower partition with holes is installed in the lower part of the furnace body to form a direct-fired exhaust gas lower combustion chamber.
  • the gas collecting chamber is connected to an exhaust gas fan through an exhaust gas discharge pipe;
  • each heat exchange and jet air box unit includes,
  • the air box body has a number of heat exchange tubes vertically arranged inside it, and a number of nozzles are arranged on one side of the air box body relative to the belt passage; an exhaust gas secondary mixing chamber connected to the heat exchange tubes is arranged between the upper and lower air box bodies. ;Put nitrogen and hydrogen protective gas into the wind box;
  • Circulation fan the port of its inlet pipe is arranged in the belt passage, and the port of its outlet pipe is located in the wind box;
  • a number of sealing devices for the steel strip to pass through are respectively provided at the upper and lower ports of the strip passage and at the strip holes of the upper and lower partitions.
  • a combustion exhaust gas thermometer is also provided in the direct-fired combustion exhaust gas secondary combustion chamber to measure the actual temperature of the combustion exhaust gas that will enter the heat exchange and injection wind box unit after the secondary combustion.
  • the thermometer detects that the exhaust temperature at the top of the heat exchange and jet air box unit is too high, the exhaust gas temperature can be reduced by adjusting the combustion air volume of the open flame burner (the open flame burner comes with a long open flame ignition burner, and the ignition burner The amount of air does not participate in the adjustment, so as to maintain the stability of the ignition burner and ensure that the remaining gas in the exhaust gas can be recombusted), so This ensures the service life of the heat exchange and jet air box unit, especially its circulation fan.
  • the sealing device is a nitrogen sealing structure, using a nitrogen sealing chamber with a nitrogen injection pipe installed on it.
  • the exhaust gas discharge pipe is connected to the waste heat boiler and the chimney.
  • a control valve is provided on the exhaust gas discharge pipe for rapid adjustment of the exhaust gas furnace pressure to better maintain furnace pressure stability.
  • the preheating is provided with a heat exchange and jet air box unit and a direct-fired combustion exhaust gas secondary combustion chamber.
  • the heat exchange and air-jet airbox unit uses heat exchange pipes (the heat exchanger is not arranged outside the furnace) to convert the direct-fired combustion exhaust gas into a secondary combustion chamber.
  • the combustion exhaust gas re-burned in the secondary combustion chamber heats the nitrogen and hydrogen protective gas recycled in the air box. Under the action of the circulating fan, the heated nitrogen and hydrogen protective gas is sprayed at high speed to the upper and lower surfaces of the strip to force convection heat exchange to achieve rapid and efficient preheating. steel.
  • An open flame burner is also provided in the direct-fired combustion exhaust gas secondary combustion chamber, which is used for the oxygen-rich secondary combustion of the gas that is not fully burned in the direct-fired combustion exhaust gas in the direct-fired combustion exhaust gas secondary combustion chamber, and the burning flame will not contact to strip steel.
  • An exhaust gas secondary mixing chamber connected to the heat exchange tube is provided between the upper and lower air box bodies.
  • the temperature of the exhaust gas is uniformized in the exhaust gas secondary mixing chamber before entering the downward air box body.
  • the sealing device is a nitrogen sealing structure with a nitrogen sealing chamber.
  • Each nitrogen sealing chamber is equipped with a nitrogen injection pipe port.
  • a sealing device is provided at the strip entrance of the preheating furnace, and a gas injection port is also provided inside to inject a small amount of sealed nitrogen or air. Its function is to prevent direct-fire combustion waste gas from overflowing outside the furnace.
  • the high-temperature combustion exhaust gas generated by the direct-fire combustion of the direct-fired furnace enters the preheating furnace through the connecting pipe.
  • the preheating furnace is equipped with multiple heat exchange and jet air box units arranged up and down in sequence.
  • the exchange pipe heats the nitrogen-hydrogen mixed gas in the wind box, and sprays high-temperature nitrogen-hydrogen mixed gas to both sides of the strip through high-speed nozzles facing both sides of the strip to rapidly heat it.
  • Strip steel, the sprayed high-temperature nitrogen-hydrogen mixed gas performs heat exchange with the low-temperature strip steel.
  • the mixed gas After the mixed gas reduces the temperature, it is pumped back from the circulating fans arranged near both sides of the strip steel to the heat exchanger in the furnace and its internal tube path.
  • the combustion exhaust gas undergoes heat exchange again to increase the temperature of the nitrogen-hydrogen mixed gas again, and then is regenerated from inside the jet air box unit. Spray to both sides of the strip, and so on.
  • the present invention adds a heat exchange and jet air box unit in the preheating furnace, and uses heated nitrogen and hydrogen protective gas to be sprayed onto the upper and lower surfaces of the strip at high speed to force convection heat exchange to achieve rapid and efficient preheating of the strip.
  • This method is different from the traditional method.
  • the heat loss of the furnace shell and protective gas channel is significantly reduced, the waste heat of direct combustion exhaust gas is more fully utilized, the heating efficiency is higher, and the heating rate is faster.
  • the direct-fired exhaust gas is used to heat the gas in the jet air box and the steel strip is preheated by the jet through the nozzle.
  • the preheating efficiency is further improved, and the heat of the direct-fired exhaust gas is more fully utilized.
  • the present invention designs heat exchange into the preheating furnace.
  • the direct-fired combustion exhaust gas mainly passes through the preheating furnace heat exchange and jet air box unit. During the passing process, the direct-fired combustion exhaust gas fully exchanges with the heat exchange pipes in the airbox. Heat, heating the nitrogen and hydrogen protective gas in the wind box, so the direct fire combustion exhaust gas in the preheating furnace is not always in direct contact with the strip (only in the high temperature section for a short period of time and the exhaust gas is a reducing atmosphere or a slightly oxidizing atmosphere) , thus avoiding overoxidation of the strip surface.
  • the present invention designs a direct-fired combustion exhaust gas secondary combustion chamber and an open flame burner in the preheating furnace.
  • the incompletely burned gas in the direct-fired combustion exhaust gas is recombusted in the semi-sealed direct-fired combustion exhaust gas on the top of the preheating furnace.
  • Oxygen-rich secondary combustion is carried out indoors, but the burning flame does not contact the strip steel, thus effectively avoiding overoxidation of the strip steel surface.
  • the strip preheating temperature is higher. Due to the high speed and high efficiency injection of high-temperature nitrogen and hydrogen protective gas for preheating, the preheating heat transfer coefficient is high.
  • the temperature of the strip after preheating can reach more than 350°C, which is higher than that of ordinary preheating furnaces.
  • the strip temperature is at least 100°C higher;
  • the temperature of the direct-fire combustion exhaust gas coming out of the preheating furnace of the present invention is usually much lower than 750°C (if a sufficient number of high-speed injection preheating units are arranged, it can even be directly discharged below 200°C), and there is no need to mix cold air into the furnace. Secondary use outside the home or no need for secondary use at all. It can be seen that the present invention not only realizes the full utilization of the waste heat of the direct-fired furnace exhaust gas, but also avoids excessive oxidation of the surface of the strip caused by the direct-fired furnace exhaust gas contacting the strip for a long time.
  • Figure 1 is a schematic structural diagram of an embodiment of the present invention
  • Figure 2 is a schematic structural diagram of the preheating furnace in the embodiment of the present invention.
  • the injection direct fire preheating system of the present invention includes: a direct fire furnace 1, a preheating Furnace 2; among them,
  • the direct-fired stove 1 includes:
  • the upper and lower ends of the furnace shell 11 are respectively provided with a furnace top roller chamber 101 and a furnace bottom roller chamber 102; the furnace top roller chamber 101 and the furnace bottom roller chamber 102 are respectively provided with steering rollers 12 and 12'; the furnace shell 11 is provided along the height direction.
  • Several direct fire heating areas 111 are provided with several direct fire burners; the upper side wall of the furnace shell 11 is provided with two through holes, and are arranged symmetrically left and right;
  • the preheating furnace 2 includes:
  • the upper side wall of the furnace body 21 is provided with two connection holes, which are symmetrically arranged left and right, and are respectively connected to the through holes in the upper part of the furnace shell 11 of the direct furnace 1 through communication pipes 22; the top of the furnace body 21 is provided with the direct furnace 1
  • the top roller chamber 101 corresponds to the furnace throat 211 for the strip to pass through; the bottom of the furnace body 21 is provided with a strip entrance and a corresponding sealing device 212 and a steering roller 23; the upper part of the furnace body 21 is provided with an upper partition with a through hole.
  • a direct-fired combustion exhaust gas secondary combustion chamber 202 is provided below the direct-fired exhaust gas upper gas collecting chamber 201, and the direct-fired combustion exhaust gas secondary combustion chamber 202 is equipped with at least one open flame burner 24 ;
  • the lower part of the furnace body 21 is provided with a lower partition plate 214 with holes to form a direct-fired exhaust gas lower gas collection chamber 203, and is connected to an exhaust gas fan 25 through an exhaust gas discharge pipe 215;
  • a number of heat exchange and jet air box units 26 are arranged along the height direction of the furnace body 21 on both sides below the direct-fired combustion exhaust gas secondary combustion chamber 202 in the furnace body 21, with a belt passage 204 formed in the middle for the strip steel to pass through;
  • Each heat exchange and jet air box unit 26 includes,
  • the wind box body 261 has a number of heat exchange tubes 262 vertically arranged in it.
  • the wind box body 261 is provided with a number of nozzles 263 on one side of the belt passage 204; the heat exchange tubes 262 are arranged between the upper and lower wind box bodies 261.
  • the connected waste gas secondary mixing chamber 205; nitrogen and hydrogen protective gas is introduced into the wind box body 261;
  • a circulating fan 264, the port of its inlet pipe is arranged in the belt threading channel 204, and the port of its outlet pipe is located in the wind box body 261;
  • a plurality of sealing devices 27, 27’, and 27′′ for the strip to pass through are respectively provided at the upper and lower ports of the strip passage 204 and at the strip holes of the upper and lower partitions 213 and 214.
  • a combustion exhaust gas thermometer 28 is also provided in the direct-fired combustion exhaust gas secondary combustion chamber 202.
  • the sealing devices 27, 27', and 27" are nitrogen-sealed structures, using nitrogen-sealed chambers with nitrogen injection pipes on them.
  • the exhaust gas discharge pipe 215 is provided with a control valve 216.
  • the strip 100 is turned upward by the steering roller in front of the direct furnace, and is first sealed by the preheating furnace entrance sealing device. It enters the preheating furnace 2 for preheating, then enters the top roller chamber of the direct-fired furnace 1, and then enters the direct-fired furnace 1 for direct heating after being turned by the steering roller. Then it enters the bottom roller chamber of the direct-fired furnace 1, and after being turned by the steering roller Keep running.
  • the direct-fired combustion exhaust gas heats the nitrogen and hydrogen protective gas through the heat exchange pipe and then the temperature of the exhaust gas drops (the nitrogen and hydrogen protective gas is blown to the upper and lower surfaces of the strip steel to preheat the strip steel under the action of the circulating fan).
  • the cooled nitrogen and hydrogen protective gas is
  • the working side (WS side) and driving side (DS side) of the preheating furnace are sucked by the circulating fan 264 into the wind box for heat exchange with the heat exchange pipe; the direct-fired combustion exhaust gas passes through the heat exchanger and the heat exchanger from top to bottom.
  • the jet air box unit under the suction of the variable frequency exhaust gas fan 25, passes through the exhaust gas discharge pipe 215 first through the waste heat boiler 200 for secondary utilization of the waste heat of the combustion exhaust gas outside the furnace, and then enters the chimney 300 for final discharge.
  • the high-temperature combustion exhaust gas exchanges heat with the strip 100 in the direct-fired exhaust gas upper gas collection chamber 201 (ie, ordinary high-temperature preheating).
  • the direct-fired combustion high-temperature combustion exhaust gas exchanges heat with the strip steel and cools down
  • the interior of the direct-fired combustion exhaust gas secondary combustion chamber 202 (close to the strip steel) is provided with sealing devices 27, 27"-nitrogen sealing chambers, connected with a nitrogen injection pipe to inject a certain pressure.
  • Nitrogen its purpose is to reduce as much as possible the direct-fired combustion exhaust gas (including incompletely burned gas) from entering the lower belt passage 204.
  • the direct-fired combustion exhaust gas no longer directly contacts the belt. Steel 100.
  • the direct-fired exhaust gas coming down from the exhaust gas secondary combustion chamber flow 202 continues to flow downward through the heat exchange tube 262.
  • heat exchange is performed to heat the nitrogen and hydrogen protective gas cyclically injected, and then enters the air jet box.
  • the exhaust gas secondary mixing chamber 205 between the exhaust gas secondary mixing chamber 205 homogenizes the temperature of the exhaust gas, and then enters the downward heat exchange and jet air box unit until it reaches the bottom direct-fired exhaust gas lower air collection chamber 203, and The strips are in contact for a small amount of heat exchange.
  • the entire structure of the preheating system does not directly contact the strip steel with the combustion exhaust gas. It is not until after the jet heat exchange that the exhaust gas in the direct-fired combustion exhaust gas collection chamber comes into contact with the belt again. The steel is in contact with a small amount of heat exchange. Since the strip is at room temperature at this time, the oxidation of the exhaust gas has a negligible impact on the surface of the strip.

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Abstract

一种喷射直火预热系统，包括：直火炉、预热炉；直火炉包括，炉壳，其内设直火加热区；预热炉包括：炉体，其上部通过连通管连接直火炉上部；其底部设带钢入口及密封装置和转向辊；炉体内上部设直火废气上集气室、直火燃烧废气二次燃烧室；炉体内下部设直火废气下集气室；若干换热与喷气风箱单元，沿炉体高度方向设于炉体内，中间形成穿带通道；换热与喷气风箱单元包括，风箱体，其内设热交换管，相对穿带通道一侧面设喷嘴；风箱体之间设废气二次混合室；循环风机，进口管道端口设于穿带通道内，出口管道端口位于风箱体内。本发明可快速预热带钢温度到350℃以上及快速加热到750℃以上；废气余热得到充分利用，可避免带钢表面生成过厚的氧化层。

Description

一种喷射直火预热系统 技术领域
本发明涉及带钢连续热处理技术领域，具体涉及一种喷射直火预热系统。
背景技术
连续退火因生产效率高，带钢表面质量好等优点已经大量取代了罩式退火。连续退火用的主要设备是连续退火炉。在连续退火炉中，立式退火炉是大型连退机组或者热镀锌机组的首选退火炉型式。通常立式退火炉包括预热段、加热段、均热段、缓冷段、快冷段等部分。当加热段使用直火加热段时，直火燃烧的废气温度可达1000℃以上。为了将直火燃烧废气的热量用到带钢上，通常把直火燃烧的废气用废气风机引流到预热段(对应设备叫预热炉)，在预热段，带钢向上运行，直火燃烧废气向下运行，运行过程中直火燃烧废气与带钢接触，预热带钢。预热带钢后的废气，经管道排到炉外，进行二次利用(通常使用余热锅炉回收热量)后排放。此技术存在如下不足：
1)预热带钢后的直火燃烧废气排放温度仍然比较高，通常会超过800℃，有时会超过850℃，超过850℃时通常需要掺入冷风将废气排放温度控制在850℃及以下才能进行二次离线利用。废气温度越高，意味着热能损失越多。可以看出，这种方法，热能一次在线利用率低，而且二次离线利用产生的蒸汽或热水在本机组往往不能全部消耗掉，因此将带来该区域能源平衡的困难。
2)由于直火燃烧废气直接接触带钢而且接触时间较长，另外在预热段需将直火燃烧废气中的过量燃气进行二次燃烧，二次燃烧火焰往往是氧化性火焰，这必然限制带钢预热温度的提高，否则，容易在带钢表面形成过厚的氧化层，引起表面质量问题，通常带钢的预热温度只能预热到250℃左右，预热效果较差。
3)在这种预热条件下，对应的直火加热，加热能力受限，加热温度也不能太高，通常只能将带钢加热到750℃及以下，进一步提高加热温度后带钢容易发生严重氧化。
发明内容
本发明的目的在于设计一种喷射直火预热系统，可以将带钢温度快速预热到至少350℃以上，并配合直火加热炉可将带钢温度快速加热到750℃以上；同时，直火燃烧废气余热得到充分利用，且可以避免直火燃烧废气在预热炉内长时间直接接触带钢，从而避免带钢表面生成过厚的氧化层。
为达到上述目的，本发明的技术方案是：
一种预热炉，所述预热炉包括：
炉体，其上部侧壁设至少两个连接孔，且左右对称设置，并分别通过连通管连接直火炉炉壳上部的通孔；炉体顶端设与所述直火炉炉顶辊室对应、供带钢穿过的炉喉；炉体底部设带钢入口及相应的密封装置和转向辊；炉体内上部设一带穿带孔的上隔板，形成直火废气上集气室；直火废气上集气室下方设直火燃烧废气二次燃烧室，直火燃烧废气二次燃烧室内设至少一只明火烧嘴；炉体内下部设一带穿带孔的下隔板，形成直火废气下集气室，并通过一废气排出管道连接一废气风机；
若干换热与喷气风箱单元，沿炉体高度方向设置于所述炉体内直火燃烧废气二次燃烧室下方的两侧，中间形成供带钢穿过的穿带通道，即预热通道；每个换热与喷气风箱单元包括，
风箱体，其内竖直设置若干热交换管，风箱体相对所述穿带通道的一侧面设置若干喷嘴；上下设置的风箱体之间设置与热交换管连通的废气二次混合室；
循环风机，其进口管道的端口设置于所述穿带通道内，其出口管道的端口位于风箱体内；
若干可供带钢穿过的密封装置，分别设置于所述穿带通道的上下端口处及上、下隔板的穿带孔处。
优选的，所述直火燃烧废气二次燃烧室内还设置燃烧废气测温计，用于测量二次燃烧之后即将进入换热与喷气风箱单元的燃烧废气的实际温度。当测温计检测到换热与喷气风箱单元顶部的废气温度过高时，可以通过调节明火烧嘴的助燃空气量来降低废气温度(明火烧嘴自带长明火点火烧嘴，而且点火烧嘴的空气量不参与调节，从而能够维持点火烧嘴的稳定，并确保废气中剩余燃气能够二次燃烧)，这样就保证了换热与喷气风箱单元特别是其循环风机的使用寿命。
优选的，所述密封装置为氮气密封结构，采用氮气密封室，其上设有氮气注入管道。
优选的，所述废气排出管道连接至余热锅炉及烟囱。
优选的，所述废气排出管道上设置控制阀，用于废气炉压的快速调节，更好地保持炉压稳定。
优选的，风箱体内通入氮氢保护气体。
本发明的预热炉可用于利用直火燃烧的废气(其温度可达1000℃以上)的热量给带钢预热。在预热炉内，带钢向上运行，直火燃烧的废气向下运行，运行过程中直火燃烧的废气与带钢接触，预热带钢。采用本发明的预热炉，可将带钢的温度快速预热到350℃以上。
本发明的预热炉中：
炉体上部侧壁设置的连接孔用于与直火炉炉壳上部的通孔连通，用于接收直火燃烧的废气；
炉体底部设置的带钢入口处的密封装置连通有氮气注入管道，通过注入一定压力的氮气，尽可能减少直火燃烧废气进入穿带通道内；
炉体内上部设置的带穿带孔的上隔板与炉体的上部形成直火废气上集气室，该直火废气上集气室与直火炉炉壳上部的通孔连通，用于容纳直火燃烧的废气，并允许该废气与带钢进行换热；
直火废气上集气室下方设置的直火燃烧废气二次燃烧室用于对来自直火废气上集气室的直火燃烧废气中的过量燃气进行二次燃烧，其设置有至少一只明火烧嘴，且直火燃烧废气二次燃烧室内靠近带钢的部位设置密封装置，该密封装置连通有氮气注入管道，通过注入氮气，尽可能减少直火燃烧废气进入穿带通道内，避免直火燃烧废气与带钢直接接触；该密封装置为氮气密封室，密封室内的氮气具有一定的压力，以尽可能减少直火燃烧废气进入穿带通道内；
炉体内下部设置的带穿带孔的下隔板与炉体的下部形成直火废气下集气室，用于收集从上部流下来的直火燃烧废气，并利用该废气对带钢进行换热；直火废气下集气室内的直火燃烧废气通过连接废气风机的废气排出管道被排出直火废气下集气室；
炉体内设置的换热与喷气风箱单元设置在直火燃烧废气二次燃烧室和直火废气下集气室之间，沿炉体高度方向设置于穿带通道两侧，利用通过热交换管下行的直火燃烧废气对热交换管外的气体(通常为氮氢保护气体)进行加热，并将加热后的气体通过所述喷嘴喷射到穿带通道内穿行的带钢上，对带钢进行预热，喷射到穿 带通道内的气体被循环风机抽出后再次送入风箱体内，与直火燃烧废气进行换热；
通过风箱体内的热交换管下行的直火燃烧废气进入炉体内设置的废气二次混合室，混合后再次进入下部的风箱体的热交换管内，重复上述热交换过程。
本发明还提供一种喷射直火预热系统，其包括：直火炉、预热炉；其中，
所述直火炉包括：
炉壳，其上下端分别设置炉顶辊室、炉底辊室；炉顶辊室、炉底辊室内分别设置转向辊；炉壳内沿高度方向设置若干直火加热区，直火加热区内设置若干直火烧嘴；炉壳上部侧壁设至少两个通孔，且左右对称设置；
所述预热炉包括：
炉体，其上部侧壁设至少两个连接孔，且左右对称设置，并分别通过连通管连接所述直火炉炉壳上部的通孔；炉体顶端设与所述直火炉炉顶辊室对应、供带钢穿过的炉喉；炉体底部设带钢入口及相应的密封装置和转向辊；炉体内上部设一穿带孔的上隔板，形成直火废气上集气室；直火废气上集气室下方设直火燃烧废气二次燃烧室，直火燃烧废气二次燃烧室内设至少一只明火烧嘴；炉体内下部设一带穿带孔的下隔板，形成直火废气下集气室，并通过一废气排出管道连接一废气风机；
若干换热与喷气风箱单元，沿炉体高度方向设置于所述炉体内直火燃烧废气二次燃烧室下方的两侧，中间形成供带钢穿过的穿带通道，即预热通道；每个换热与喷气风箱单元包括，
风箱体，其内竖直设置若干热交换管，风箱体相对所述穿带通道的一侧面设置若干喷嘴；上下设置的风箱体之间设置与热交换管连通的废气二次混合室；风箱体内通入氮氢保护气体；
循环风机，其进口管道的端口设置于所述穿带通道内，其出口管道的端口位于风箱体内；
若干可供带钢穿过的密封装置，分别设置于所述穿带通道的上下端口处及上、下隔板的穿带孔处。
优选的，所述直火燃烧废气二次燃烧室内还设置燃烧废气测温计，用于测量二次燃烧之后即将进入换热与喷气风箱单元的燃烧废气的实际温度。当测温计检测到换热与喷气风箱单元顶部的废气温度过高时，可以通过调节明火烧嘴的助燃空气量来降低废气温度(明火烧嘴自带长明火点火烧嘴，而且点火烧嘴的空气量不参与调节，从而能够维持点火烧嘴的稳定，并确保废气中剩余燃气能够二次燃烧)，这样 就保证了换热与喷气风箱单元特别是其循环风机的使用寿命。
优选的，所述密封装置为氮气密封结构，采用氮气密封室，其上设有氮气注入管道。
优选的，所述废气排出管道连接至余热锅炉及烟囱。
优选的，所述废气排出管道上设置控制阀，用于废气炉压的快速调节，更好地保持炉压稳定。
在本发明所述预热系统中：
所述预热设置换热与喷气风箱单元及直火燃烧废气二次燃烧室，所述换热与喷气风箱单元采用热交换管道(热交换器不是布置在炉外)，将直火燃烧废气二次燃烧室再次燃烧的燃烧废气加热风箱体内循环利用的氮氢保护气体，在循环风机的作用下加热后的氮氢保护气体高速喷射到带钢上下表面强制对流换热，实现快速高效预热带钢。
在直火燃烧废气二次燃烧室内还设置明火烧嘴，用于直火燃烧废气中未充分燃烧的燃气在直火燃烧废气二次燃烧室内进行富氧二次燃烧，且燃烧的火焰不会接触到带钢。
上下设置的风箱体之间设置与热交换管连通的废气二次混合室，在该废气二次混合室对废气温度进行均匀化处理，然后再进入下行的风箱体。
所述密封装置为氮气密封结构，设有氮气密封室，氮气密封室内都设有氮气注入管道口，通过向氮气密封室内内通入密封氮气，维持相对高压，避免大量直火燃烧废气进入炉内换热与喷气风箱单元内部的穿带通道，从而可以避免直火燃烧废气过量氧化带钢表面。
所述预热炉的带钢入口处设密封装置，其内部也设置气体注入口，喷吹少量密封氮气或空气，其作用是避免直火燃烧废气溢出至炉外。
生产过程中，直火炉直火燃烧产生的高温燃烧废气通过连通管进入预热炉，预热炉内设有多个依次上下排列的换热与喷气风箱单元，该换热与喷气风箱单元的热交换管道(高温燃烧废气走管程，保护气体走壳程)对风箱体内的氮氢混合气体加热，通过正对带钢两侧的高速喷嘴向带钢两面喷吹高温氮氢混合气体，快速加热带钢，喷出的高温氮氢混合气体与低温带钢进行热交换，混合气体降低温度之后从布置在靠近带钢两侧边的循环风机抽回到炉内热交换器与其内部的走管程的燃烧废气再次进行热交换，再次提升氮氢混合气体的温度，而后从该喷气风箱单元内部再 喷向带钢两面，如此循环往复。
与传统直火加热预热炉的结构相比，本发明的优点和有益效果在于：
1.本发明在预热炉内增设了换热与喷气风箱单元，利用加热的氮氢保护气体高速喷射到带钢上下表面强制对流换热，实现快速高效预热带钢，此方法与传统的预热方法相比，炉壳及保护气体通道的热量损失显著减少，燃烧直火废气余热利用更充分、加热效率更高、加热速率更快。利用直火废气对喷气风箱内气体加热并通过喷嘴对带钢带了喷气预热，相较现有技术，进一步提高了预热效率，且直火废气热量利用更加充分。
2.本发明将热交换设计到了预热炉内，直火燃烧废气主要从预热炉换热与喷气风箱单元通过，在通过过程中直火燃烧废气与风箱内的热交换管道进行充分的换热，加热风箱内的氮氢保护气体，因此在预热炉内直火燃烧废气不是一直与带钢直接接触(仅在高温段短时直接接触而且此时废气属于还原性气氛或微氧化气氛)，从而可以避免带钢表面过氧化。
3.本发明在预热炉内设计直火燃烧废气二次燃烧室及明火烧嘴，直火燃烧废气中的未充分燃烧的燃气在预热炉顶部的半密封的直火燃烧废气二次燃烧室内进行富氧二次燃烧，但燃烧的火焰不接触带钢，因此有效避免了带钢表面过氧化。
4.采用本发明预热，带钢预热温度更高，由于高温氮氢保护气体高速高效喷射预热换热系数高，预热后的带钢温度可以达到350℃以上，比普通预热炉带钢温度至少高出100℃；
5.本发明所述预热炉出来的直火燃烧废气温度通常远低于750℃(如果高速喷射预热单元布置数量足够多的话甚至可以达到200℃以下直接排放)，无需掺冷空气进行炉外二次利用或根本无需二次利用。可以看出，本发明既实现了直火炉废气余热的充分利用，又避免了直火炉废气过长时间接触带钢造成带钢表面过量氧化。
附图说明
图1为本发明实施例的结构示意图；
图2为本发明实施例中预热炉的结构示意图。
具体实施方式
参见图1、图2，本发明所述的喷射直火预热系统，其包括：直火炉1、预热 炉2；其中，
所述直火炉1包括：
炉壳11，其上下端分别设置炉顶辊室101、炉底辊室102；炉顶辊室101、炉底辊室102内分别设置转向辊12、12’；炉壳11内沿高度方向设置若干直火加热区111，直火加热区111内设置于若干直火烧嘴；炉壳11上部侧壁设两个通孔，且左右对称设置；
所述预热炉2包括：
炉体21，其上部侧壁设两个连接孔，且左右对称设置，并分别通过连通管22连接所述直火炉1炉壳11上部的通孔；炉体21顶端设与所述直火炉1炉顶辊室101对应、供带钢穿过的炉喉211；炉体21底部设带钢入口及相应的密封装置212和转向辊23；炉体21内上部设一带穿带孔的上隔板213，形成直火废气上集气室201；直火废气上集气室201下方设直火燃烧废气二次燃烧室202，直火燃烧废气二次燃烧室202内设至少一只明火烧嘴24；炉体21内下部设一带穿带孔的下隔板214，形成直火废气下集气室203，并通过一废气排出管道215连接一废气风机25；
若干换热与喷气风箱单元26，沿炉体21高度方向设置于所述炉体21内直火燃烧废气二次燃烧室202下方的两侧，中间形成供带钢穿过的穿带通道204；每个换热与喷气风箱单元26包括，
风箱体261，其内竖直设置若干热交换管262，风箱体261相对所述穿带通道204的一侧面设置若干喷嘴263；上下设置的风箱体261之间设置与热交换管262连通的废气二次混合室205；风箱体261内通入氮氢保护气体；
循环风机264，其进口管道的端口设置于所述穿带通道204内，其出口管道的端口位于风箱体261内；
若干可供带钢穿过的密封装置27、27’、27”，分别设置于所述穿带通道204的上下端口处及上、下隔板213、214的穿带孔处。
优选的，所述直火燃烧废气二次燃烧室202内还设置燃烧废气测温计28。
优选的，所述密封装置27、27’、27”为氮气密封结构，采用氮气密封室，其上设有氮气注入管道。
优选的，所述废气排出管道215上设置控制阀216。
带钢100经直火炉前转向辊转向向上运行，先经过预热炉入口密封装置密封后 进入预热炉2进行预热，接着进入直火炉1的炉顶辊室，经转向辊转向后进入直火炉1进行直火加热，然后进入直火炉1的炉底辊室，经转向辊转向后继续运行。
直火燃烧废气经热交换管道将氮氢保护气体加热后废气温度下降(氮氢保护气体在循环风机的作用下喷吹到带钢上下表面预热带钢)，降温后的氮氢保护气体在预热炉的工作侧(WS侧)和驱动侧(DS侧)两侧被循环风机264再抽吸到风箱内与热交换管道进行换热；直火燃烧废气从上而下依次通过换热与喷气风箱单元，在变频废气风机25的抽吸下，通过废气排出管道215先经过余热锅炉200进行燃烧废气余热的炉外二次利用，再进入烟囱300内最终排放。
参见图2，在喷气热交换之前高温燃烧废气在直火废气上集气室201与带钢100进行换热(即普通高温预热)，直火燃烧的高温燃烧废气与带钢换热降温之后进入直火燃烧废气二次燃烧室202，直火燃烧废气二次燃烧室202的内部(靠近带钢的部位)设置密封装置27、27”-氮气密封室，连通有氮气注入管道注入一定压力的氮气，其目的是尽可能减少直火燃烧废气(含未充分燃烧的燃气)进入下部的穿带通道204内，从直火燃烧废气二次燃烧室202开始，直火燃烧废气不再直接接触带钢100。
从废气二次燃烧室流202下来的直火废气经热交换管262继续向下流动，如上文所述，流动过程中进行热交换加热循环喷射的氮氢保护气体，然后进入喷气风箱体之间的废气二次混合室205，在该废气二次混合室205对废气温度进行均匀化处理，然后再进入下行的换热与喷气风箱单元，直至到达底部直火废气下集气室203，与带钢接触进行少量换热。
所述预热系统的整个结构，从预热炉顶部氮气密封装置到底部氮气密封装置带钢与燃烧废气都不直接接触，一直到喷气热交换之后直火燃烧废气集气室内废气才再次与带钢接触进行少量换热，由于此时带钢为室温带钢，废气的氧化性对带钢表面的影响已可以忽略不计。
上述实施例仅仅是阐述性的，并非用于限制本发明的范围。利用本发明构思衍生变化的方案也在本申请的保护范围内。

Claims (12)

  1. 一种预热炉，其特征在于，所述预热炉包括：
    炉体，其上部侧壁设至少两个连接孔，且左右对称设置，并分别通过连通管连接直火炉炉壳上部的通孔；炉体顶端设与直火炉炉顶辊室对应、供带钢穿过的炉喉；炉体底部设带钢入口及相应的密封装置和转向辊；炉体内上部设一带穿带孔的上隔板，形成直火废气上集气室；直火废气上集气室下方设直火燃烧废气二次燃烧室，直火燃烧废气二次燃烧室内设至少一只明火烧嘴；炉体内下部设一带穿带孔的下隔板，形成直火废气下集气室，并通过一废气排出管道连接一废气风机；
    若干换热与喷气风箱单元，沿炉体高度方向设置于所述炉体内直火燃烧废气二次燃烧室下方的两侧，中间形成供带钢穿过的穿带通道；每个换热与喷气风箱单元包括，
    风箱体，其内竖直设置若干热交换管，风箱体相对所述穿带通道的一侧面设置若干喷嘴；上下设置的风箱体之间设置与热交换管连通的废气二次混合室；
    循环风机，其进口管道的端口设置于所述穿带通道内，其出口管道的端口位于所述风箱体内；和
    若干可供带钢穿过的密封装置，分别设置于所述穿带通道的上下端口处及上、下隔板的穿带孔处。
  2. 如权利要求1所述的预热炉，其特征在于，所述直火燃烧废气二次燃烧室内还设置燃烧废气测温计。
  3. 如权利要求1所述的预热炉，其特征在于，所述密封装置为氮气密封结构，采用氮气密封室，其上设有氮气注入管道。
  4. 如权利要求1所述的预热炉，其特征在于，所述废气排出管道连接至余热锅炉及烟囱。
  5. 如权利要求1或4所述的预热炉，其特征在于，所述废气排出管道上设置控制阀。
  6. 如权利要求1所述的预热炉，其特征在于，风箱体内通入氮氢保护气体。
  7. 一种喷射直火预热系统，其特征在于，包括：直火炉、预热炉；其中，
    所述直火炉包括：
    炉壳，其上下端分别设置炉顶辊室、炉底辊室；炉顶辊室、炉底辊室内分别设 置转向辊；炉壳内沿高度方向设置若干直火加热区，直火加热区内设置若干直火烧嘴；炉壳上部侧壁设至少两个通孔，且左右对称设置；
    所述预热炉包括：
    炉体，其上部侧壁设至少两个连接孔，且左右对称设置，并分别通过连通管连接所述直火炉炉壳上部的通孔；炉体顶端设与所述直火炉炉顶辊室对应、供带钢穿过的炉喉；炉体底部设带钢入口及相应的密封装置和转向辊；炉体内上部设一穿带孔的上隔板，形成直火废气上集气室；直火废气上集气室下方设直火燃烧废气二次燃烧室，直火燃烧废气二次燃烧室内设至少一只明火烧嘴；炉体内下部设一带穿带孔的下隔板，形成直火废气下集气室，并通过一废气排出管道连接一废气风机；
    若干换热与喷气风箱单元，沿炉体高度方向设置于所述炉体内直火燃烧废气二次燃烧室下方的两侧，中间形成供带钢穿过的穿带通道；每个换热与喷气风箱单元包括，
    风箱体，其内竖直设置若干热交换管，风箱体相对所述穿带通道的一侧面设置若干喷嘴；上下设置的风箱体之间设置与热交换管连通的废气二次混合室；
    循环风机，其进口管道的端口设置于所述穿带通道内，其出口管道的端口位于风箱体内；
    若干可供带钢穿过的密封装置，分别设置于所述穿带通道的上下端口处及上、下隔板的穿带孔处。
  8. 如权利要求7所述的喷射直火预热系统，其特征在于，所述直火燃烧废气二次燃烧室内还设置燃烧废气测温计。
  9. 如权利要求7所述的喷射直火预热系统，其特征在于，所述密封装置为氮气密封结构，采用氮气密封室，其上设有氮气注入管道。
  10. 如权利要求7所述的喷射直火预热系统，其特征在于，所述废气排出管道连接至余热锅炉及烟囱。
  11. 如权利要求7或10所述的喷射直火预热系统，其特征在于，所述废气排出管道上设置控制阀。
  12. 如权利要求7所述的喷射直火预热系统，其特征在于，风箱体内通入氮氢保护气体。
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