US3801267A - Furnace having a combustion pressure elevating device - Google Patents

Furnace having a combustion pressure elevating device Download PDF

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Publication number
US3801267A
US3801267A US00330150A US3801267DA US3801267A US 3801267 A US3801267 A US 3801267A US 00330150 A US00330150 A US 00330150A US 3801267D A US3801267D A US 3801267DA US 3801267 A US3801267 A US 3801267A
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United States
Prior art keywords
furnace
zone
gas
pressure
jet
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Expired - Lifetime
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US00330150A
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English (en)
Inventor
R Okuno
H Fujii
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.)
Kawasaki Heavy Industries Ltd
Kawasaki Motors Ltd
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Kawasaki Heavy Industries Ltd
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/004—Heating the product
    • 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 tunnel furnace
    • F27B9/22—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 tunnel furnace on rails, e.g. under the action of scrapers or pushers
    • 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
    • F27B9/12—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity with special arrangements for preheating or cooling the charge
    • F27B2009/122—Preheating
    • 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 peculiar to furnaces of these types
    • F27B9/36—Arrangements of heating devices
    • F27B2009/3638—Heaters located above and under the track
    • 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
    • F27D2003/008—Means for moving, conveying, transporting the charge in the furnace or in the charging facilities comprising cross-beams or gantry cranes
    • 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
    • F27D9/00—Cooling of furnaces or of charges therein
    • F27D2009/007—Cooling of charges therein
    • F27D2009/0089—Quenching
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27M—INDEXING SCHEME RELATING TO ASPECTS OF THE CHARGES OR FURNACES, KILNS, OVENS OR RETORTS
    • F27M2001/00—Composition, conformation or state of the charge
    • F27M2001/15—Composition, conformation or state of the charge characterised by the form of the articles
    • F27M2001/1539—Metallic articles
    • F27M2001/1547—Elongated articles, e.g. beams, rails
    • F27M2001/1552—Billets, slabs

Definitions

  • the present invention relates to a furnace for industrial use having a device for elevating the pressure of a combustion gas to be fed therein, which, in a part of its combustion zone is provided with a number of projecting jet nozzles being adapted to provide to the upper and lower portions of the said combustion zone high speed jet zones, each at a determined distance from substances tobe treated, such as, steel ingot or blooms, wherein a high temperature combustion gas which has been fed from another combustion zone is jetted out from the said nozzles under high speed into the said high speed jet zone whereby a heat transfer is efficiently conducted therein between the said gas streams and the said substances by utilizing the high coefficient of heat transfer occurring on the surface of said substances due to the said high-speed gas streams, characterized in that a device for elevating the pressure of the said
  • the subject matter of the present invention relates to a reheating furnace for reheating substances, such as, steel ingot or blooms.
  • the furnace in a part of its combustion zone is provided with a number of jet nozzles being arranged in the upper or upper and lower portions thereof, each at a distance from the substances to be reheated.
  • a high temperature combustion gas is introduced directly from another combustion zone into the nozzles by means of a pressure elevating apparatus which operates to elevate the pressure of the high temperature combustion gas and also suck the said gas by the use of a jet stream of a low temperature gas.
  • Q, total heat quantity required in the furnace Kcal/h.
  • Qn net heat quantity required to heat steel substance
  • Qw heat quantity released through wall, etc. (loss of heat quantity)
  • Qs heat quantity released and radiated through shutter, etc.
  • the above is ajproportion of the heat quantity required per kg of the steel substance to be treated, on the basis of the total heat quantity.
  • V3 is exhaust gas quantity-Nm lNm fuel of (kg), and ig is an enthalpy of the exhaust gas, kcal/Nm.
  • an efficient utilization of an exhaust gas, which has been exhausted from a reheating furnace is accomplished by increasing the heat transfer efficiency in the interior of the convection zone of the furnace.
  • the present invention is based upon the application of such phenomenon to a reheating furnace so that a high coefficient of heat transfer may be attained on the surface of a plate to which jet streams are blown off.
  • the present reheating furnace comprising a plurality of jet nozzles which are provided in the upper and lower portions of its combustion zone (i.e., reheating zone), the materialsto be treated being conveyed between the said upper and lower nozzles, whereby a high temperature combustion gas which has been forwarded from another combustion zone is jetted out from the respective nozzles thereby efficiently to carry out the heat transfer'between the said substances and the said gas;
  • heat transfer is conducted in a high speed jet zone.
  • Another object of the present invention is to jet out a low temperature exhaustv gas which has been exhausted from a furnace by the use of a blower, into a forwarding duct for a high temperature combustion gas under high speed, for feeding a high temperature combustion gas from another combustion zone to the jet nozzles, thereby to elevate with ease the pressure of the mixed gas consisting of the said low temperature exhaust gas and said high temperature combustion gas from another combustion zone.
  • this device for forwarding the said high-speed low temperatureexhaust gas is referred to as a device for elevating the pressure of the said high temperature combustion gas.
  • the substances to be treated may efficiently be heated in the high-speed jet zone by virtue of the efficient heat transfer which may be conducted in said zone between the said substances and the high-speed and hightemperature jet gas streams, and further, the heat quantity of the high-temperature combustion gas may also be utilized efficiently, and as a result, the loss of exhaust gas is 'extermely reduced. Accordingly, a great advantage results therefrom, in terms of reduction of the specific heat consumption of the furnace economies in fuel expenses, etc.
  • FIG. -I' is a sectional view of an industrial furnace which is provided with a high-speed jet zone in its convection zone and a device for elevating the pressure of a high temperature combustion gas by the use of low temperature exhaust gas jet streams for feeding the high temperature combustion gas.
  • 'FIG.2 is a diagram explaining the principle of the device for elevating the pressure of the high temperature combustion gas.
  • FIG. 3 is a sectional view of a preheating apparatus wherein a high-speed jet zone is independently separated from an indistrial furnace body.
  • FIG. 1 is a sectional view of a fivezone continuous heating furnace which is provided with a pressure elevating device of the present invention in its convection zone.
  • This furnace is an extraction type furnace which is provided with a soaking bed at the pusher outlet part and which consists of five combustion zones in allin the upper and the lower portions.
  • FIG. 1 (a) is a soaking zone, (b) is a heating zone, (c) is a preheating zone, and (d) is a highspeed jet zone which corresponds to the convection zone of the conventional furnace.
  • Substances (l) to be treated are pushed into the furnace from the side of the high-speed jet zone by means of a pusher and are forwarded to an extrusion outlet part, sliding on the skid pipe (2) which is supported by post pipes (3) and are heated successively.
  • the temperature of each combustion zone varies, depending upon the quality of the substances to be heated, and, in general, in the case of normal steels, (a) is l,250C 1,300C, and (b) and (c) are 1,300Cl ,3 C, respectively. In each zone, the height thereof is so high as to be able efficiently to absorb radiation heat.
  • the temperature of an exhaust gas at the outlet of the furnace is from 1,000C to at most l,200C, and the furnace efficiency is about percent.
  • a number of jet nozzles 4 composed of refractory materials are provided in the upper and lower portions of the high-speed jet zone (d), each with a determined distance from the substances to be treated.
  • the disposition of the nozzles may freely be selected in both of the upper and the lower sides, depending upon the temperature distribution state of the substances to be treated, in the form of a zigzag arrangement or any other optional arrangement, with a determined interval between the respective nozzles.
  • the fizing angle thereof it is possible to fix the nozzles in the vertical direction to the substances to be treated or with a certain inclined angle to the said substances.
  • any optional one may be selected depending upon the use, say with a cut section of a circular shape, an elliptical shape, a rectangular shape, etc.
  • the high-speed jet zone consists of a casing having its interior side a lining of a refractory body or an insulation body, and through the casing is pierced the nozzles 4 into the interior of the zone.
  • the height of the zone is kept high enough sufficiently to feed the combustion gas which has been jetted out from the said nozzles to the outlet, passing through the upper and the lower portions in the zone without interfering with the effect of the jetstreams.
  • the nozzles 4 are connected to a combustion gas duct 5 which is supported by a large size ceiling beam.
  • the combustion gas duct 5 is connected, via a header, to a duct 6 for a high temperature combustion gas which has been extracted from another combustion zone of the furnace, such as, in this case, from the middle'part between the heating zone and the preheating zone.
  • a duct 6 for a high temperature combustion gas which has been extracted from another combustion zone of the furnace, such as, in this case, from the middle'part between the heating zone and the preheating zone.
  • an ejector nozzle 8 In the interior of the duct 6 with a lining of a refractory body 7 is inserted an ejector nozzle 8, and the other end of the said nozzle 8 is connected to a blower 9'via a butterfly 10.
  • the other outlet of the blower 9 is connected via a partition valve 11 to a branch duct 12 which leads to a low temperature fluid to a jet film nozzle 13 to form a jet film for gas sealing between the preheating zone (c) and the high-speed jet zone (d).
  • the pressure in the interior of the furnace is controlled by means of a controlling damper 14 which is provided in front of the combustion gas pressure elevating device.
  • a supply device for feeding the high temperature combustion gas to the high-speed jet zone is required.
  • a blower has hitherto been used as such supply device for feeding the fluid.
  • the high temperature combustion gas having a temperature of about.
  • the present invention is based upon the observation that by oppositely using an ejector which yields vaccum by the jet stream from the nozzle, the pressure of a large amount of high temperature combustion gas may be elevated by means of a small amount of high pressure air of low temperature exhaust gas. That is, in the present device, the nozzle 8 is inserted into a duct (6) for the high temperature combustion gas, a part of the low temperature exhaust gas in the flue (e) is sucked by means of the blower 9 which is resistant to, for example, a temperature of about 500C, and the thus sucked gas is jetted out under high speed from the said nozzle 8.
  • a low temperature exhaust gas is used in place of air for the purpose of increasing the efficiency of the device as much as possible.
  • FIG. 2 shows the principle of the pressure elevating device of the present invention.
  • a low temperature exhaust gas the pressure of which has been elevated to some degree by means of a blower, is jetted out from the nozzle as shown in the said FIG. 2.
  • a high temperature combustion gas is sucked by means of the low temperature exhaust gas streams which are jetted out under high speed at the section taken on line l-l of the said FIG. 2.
  • both gases are mixed, and then the mixed gas is flown out therefrom whereupon the pressure thereof has finally been elevated.
  • the total pressure after mixing the gases is as follows, the dynamic pressure beingy 2(W /2g):
  • FIG. 3 shows the embodiment of the said separate construction. That is, the exhaust gas which has been exhausted from a furnace as a high temperature fluid is extracted directly or via a recuperator, and then the substance to be treated, which has been fed into the furnace, is preheated by utilizing the said exhaust gas.
  • an independent conveyor to convey the substances into the furnace is provided, apart from the furnace body. As to the said conveyor, it is possible to convey the substances by means of a pusher or of a walking beam type conveyor.
  • the substances are exposed to the high-speed and high temperature combustion gas jet streams which are jetted out from the jet nozzles (4) provided in both of the upper and the lower portions in the zone to accept the heat energy of the said jet streams, as being conveyed by means of the said conveyor, whereby the temperature of the said substances themselves is elevated and then the substances are extracted.
  • other attended equipments they are the same as in the combined case as mentioned above (FIG. 1), and thus the explanation thereof is omitted.
  • the use of such independent apparatus results in various merits, such as an advantageous improvement in furnace efficiency without any drastic re-construction of a conventional furnace, an easy increase of furnace capacity, etc.
  • the present invention involved the following merits:
  • V co ti n ut i s type heating furnace of 170 T/ H is exemplified in the followingzThis furnace is a five-zone type consisting of one soaking zone, and two preheating zones and heating zones, each in the upper and the lower portions, and in addition thereto, one high-speed jet zone according to the present invention. The calculation of the heat quantity thereof is explained as follows:
  • the exhaust gas temperature is about 460C
  • a reheating furnace for industrial use comprising: a plurality of longitudi- 'nally extending combustion zones receiving in sebe fed into the high-speed jet zone is 1,250C and the jet speed is l 10 m/s, the average coefficient of the heat transfer onthe surface of the treated substances is as follows: a
  • the necessary heat quantity (Qh) is the soaking zone and the heating zone is calculated by Q2 Qj.
  • the necessary heat quantity to be used therein is 28.1 X 10 Kcal/h
  • the temperature of the exhaust gas which has finally been exhausted after being jetted into the jet zone and being heat-transferred therein with the materials to be treated corresponds to about 460C, the enthalpy of quence, substances to be treated, one of said zones comprising a plurality of longitudinally spaced jet nozzles facing said substances and ,set a predetermined distance therefrom, duct means commonly connected to said jet nozzles and fluid connected to another of said combustion zones for bleeding high temperature combustion gas therefrom, and ejector nozzles within said duct means facing downstream from the duct connection to said high temperature combustion zone, pipe means fluid coupling said nozzles with the low temperature exhaust gas from said furnace, and

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Details (AREA)
  • Tunnel Furnaces (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
US00330150A 1972-03-03 1973-02-06 Furnace having a combustion pressure elevating device Expired - Lifetime US3801267A (en)

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JP47022502A JPS5118205B2 (ko) 1972-03-03 1972-03-03

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3920382A (en) * 1974-08-14 1975-11-18 Bloom Eng Co Inc Method and apparatus for heat treating articles in a recirculating type furnace
US4168951A (en) * 1976-10-15 1979-09-25 Luossavaara-Kiirunavaara Aktiebolag Method of sintering and apparatus for carrying out the method
US4214868A (en) * 1978-06-21 1980-07-29 Itoh Iron & Steel Works Co. Ltd. Method of and an apparatus for soaking steel pieces
US4529379A (en) * 1983-09-28 1985-07-16 Dicastri Peter Cooking apparatus
US4863377A (en) * 1986-04-08 1989-09-05 Neuweiler Ag Apparatus for the hydraulic conveyance of substances and use thereof
US4828483B1 (en) * 1988-05-25 1994-03-22 Bloom Eng Co Inc Method and apparatus for suppressing nox formation in regenerative burners
US6183246B1 (en) * 1998-11-10 2001-02-06 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method of heating a continuously charged furnace particularly for steel-making products, and continuously charged heating furnace
US20180185954A1 (en) * 2015-06-26 2018-07-05 Thyssenkrupp Steel Europe Ag Method for producing a material composite in a rolling system and use of the rolling system

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5236844B2 (ko) * 1974-04-10 1977-09-19
JPS5114807A (ja) * 1974-07-30 1976-02-05 Ishikawajima Harima Heavy Ind Netsushoriro
JPS5220935A (en) * 1975-06-28 1977-02-17 Daido Steel Co Ltd Method of and device for heat treating materials to be treted such as wire rods
JPS527810U (ko) * 1975-07-04 1977-01-20

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3920382A (en) * 1974-08-14 1975-11-18 Bloom Eng Co Inc Method and apparatus for heat treating articles in a recirculating type furnace
US4168951A (en) * 1976-10-15 1979-09-25 Luossavaara-Kiirunavaara Aktiebolag Method of sintering and apparatus for carrying out the method
US4214868A (en) * 1978-06-21 1980-07-29 Itoh Iron & Steel Works Co. Ltd. Method of and an apparatus for soaking steel pieces
US4529379A (en) * 1983-09-28 1985-07-16 Dicastri Peter Cooking apparatus
US4863377A (en) * 1986-04-08 1989-09-05 Neuweiler Ag Apparatus for the hydraulic conveyance of substances and use thereof
US4828483B1 (en) * 1988-05-25 1994-03-22 Bloom Eng Co Inc Method and apparatus for suppressing nox formation in regenerative burners
US6183246B1 (en) * 1998-11-10 2001-02-06 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Method of heating a continuously charged furnace particularly for steel-making products, and continuously charged heating furnace
US20180185954A1 (en) * 2015-06-26 2018-07-05 Thyssenkrupp Steel Europe Ag Method for producing a material composite in a rolling system and use of the rolling system

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Publication number Publication date
JPS4889808A (ko) 1973-11-24
JPS5118205B2 (ko) 1976-06-08

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