US3157491A - Method of operating a blast furnace - Google Patents

Method of operating a blast furnace Download PDF

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Publication number
US3157491A
US3157491A US168200A US16820062A US3157491A US 3157491 A US3157491 A US 3157491A US 168200 A US168200 A US 168200A US 16820062 A US16820062 A US 16820062A US 3157491 A US3157491 A US 3157491A
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US
United States
Prior art keywords
slurry
coal
oil
furnace
blast
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.)
Expired - Lifetime
Application number
US168200A
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English (en)
Inventor
Ogden A Thomas
Leo L Meinert
Harold G Houlton
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.)
Ashland LLC
Original Assignee
Ashland Oil Inc
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
Priority to BE627469D priority Critical patent/BE627469A/xx
Application filed by Ashland Oil Inc filed Critical Ashland Oil Inc
Priority to US168200A priority patent/US3157491A/en
Priority to DE19631433290 priority patent/DE1433290A1/de
Priority to GB1609/63A priority patent/GB1025647A/en
Priority to FR922195A priority patent/FR1344768A/fr
Priority to AT49063A priority patent/AT262348B/de
Priority to SE707/63A priority patent/SE303774B/xx
Application granted granted Critical
Publication of US3157491A publication Critical patent/US3157491A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace
    • C21B5/001—Injecting additional fuel or reducing agents
    • C21B5/003—Injection of pulverulent coal
    • C21B5/004—Injection of slurries
    • E—FIXED CONSTRUCTIONS
    • E05—LOCKS; KEYS; WINDOW OR DOOR FITTINGS; SAFES
    • E05F—DEVICES FOR MOVING WINGS INTO OPEN OR CLOSED POSITION; CHECKS FOR WINGS; WING FITTINGS NOT OTHERWISE PROVIDED FOR, CONCERNED WITH THE FUNCTIONING OF THE WING
    • E05F1/00—Closers or openers for wings, not otherwise provided for in this subclass
    • E05F1/02—Closers or openers for wings, not otherwise provided for in this subclass gravity-actuated, e.g. by use of counterweights
    • E05F1/04—Closers or openers for wings, not otherwise provided for in this subclass gravity-actuated, e.g. by use of counterweights for wings which lift during movement, operated by their own weight
    • E05F1/06—Mechanisms in the shape of hinges or pivots, operated by the weight of the wing
    • E05F1/061—Mechanisms in the shape of hinges or pivots, operated by the weight of the wing with cams or helical tracks

Definitions

  • This invention relates to the operation of a blast furnace for reducing iron ore to metallic iron. More particularly, the invention relates to a method of operating a blast furnace using a fuel which comprises a slurry of particulate coal suspended in-oil.
  • the furnace In the conventional method of operating a blast furnace, the furnace is charged with a mixture principally of iron ore, coke and limestone, usually with lesser amounts of other iiuxing and/or metallurgical materials.
  • the colte supplies fuel for heating the mass and also comprises a reducing agent for reducing the iron oxide of the ore to the basic metal.
  • Air preheated to a temperature of about 100G-2500" F. is blown into the furnace under pressure through ports or tuyeres near the bottom of the furnace. Under the conditions in the furnace, the coke burns incompletely in the air to form carbon monoxide, which reduces the ore to ironwith the accompanying formation of carbon dioxide.
  • the limestone is a slag-forming ingredient, and combines With various siliceous impurities or gangue in the ore to form a slag which floats on the molten iron at the bottom of the furnace.
  • Carbon monoxide, carbon dioxide and the inactiveV atmospheric gases travel upwardly through the charge or burden, and are collected at the top of the furnace and used to supply heat to stoves in which the incoming air is preheated.
  • the temperature in the region adjacent the tuyeres is very high, typically about 3600 F., at which temperature the iron is a white hot liquid.
  • the ore and coke and the vlimestone burden are supported over the pool of iron, and the colte is continually burned away at the bottom, which causes a gradual settling of the burden and colte in the furnace.
  • the burden is rendered relatively permeable to the blast by the coke and in some cases by the use of pelletized or treated ore, so that the blast can penetrate upwardly through it and so that the burden will settle more evenly as the coke burns away at the bottom. Such operation is conventional and affords the background for this invention.
  • At least a part of the conventional coke charge is replaced by a mixture or slurry of relatively coarse coal particles suspended in oil, which is injected into the furnaceeither directlyor through the tuyeres.
  • a coal-oil slurry of the type to be described possesses excellent characteristics as a metallurgical fuel.
  • oil and coal are relatively less expensive than coke, and their use in place of colte substantially reduces overall fuel costs of blast furnace operations in many instances.
  • Slurry fuels also afford more flexible control over furnace operation, in that the fuel input can readily be adjusted to meet changing conditions, Whereas the rate at which the conventional coke charge burns is subject to relativelylittle control.
  • Fuel oil itself has heretofore been used as a blast furnace fuel. We have found, however, that a fuel oil-coal slurry, when produced and used in accordance with the method to be described, affords important economic advantages over fuel oil alone. In many cases, coal isless expensive than either coke or oil, and, if properly used with oil, will still further improve the favorable economics of oil alone. t
  • coal is comminuted or ground to particles the nominal maximum size of which is about 1/16 to 3%.
  • This coal is mixed with fuel oil in the approximate proportions of 40-70% by weight coal to 60 to 30% oil.
  • the oil used may be a heavy fuel oil or a residual oil, preferably a so-called No. 6 oil or Bunker C oil, having a Saybolt Furol viscosity of between and 1000 seconds at 122 F., and is heated to a temperature of about 15G-300 F. or higher.
  • the coal Upon mixing, the coal forms a dynamic suspension with the oil.
  • the suspension On account of the relatively coarse size of the coal particles, the major portion of which usually will not pass a No. 40 screen, the suspension is highly unstable, and the particles tend to settle out rapidly.
  • this is effectedl by preparing the slurry on a continuous basis at the rate at which it is to be used, and by agitating the slurry up to the time it is pumped to the blast furnace.
  • a slurry in accordance with this invention will remain in dynamic suspension when moving in a 11/2" pipe at a flow rate of 0.1 foot per second.
  • the apparent viscosity of the slurry mixnire depends primarily on the size gradation of the coal.
  • the minimum ow velocity for maintaining the coal particles in suspension also depends primarily on the gradation of the coal.
  • the proportion of coal in the slurry should be as Ylarge as possible, and in practice it has'been found that dispersions of 55-65 or higher are desirable for most economical operation of the furnace.
  • Prior art coal-oil fuels were vusually/'limited to maximum coal contents of 30 or '40%,
  • Yspecic oil used the distribution of particle sizes in the coal, the proportion of coal in the slurry, and the tem-V peratureY of the mixture.
  • the viscosity of theV mixture decreases rapidly with increasing temperatures; for example, in one instance eating the slurry from 150 F. to 180 F. decreased its viscosity from 4250 seconds, Saybolt Furol, to 2040.
  • the slurry is heated to a temperature of at least150 F. and'preferably as highas 300 F. or higher if possible in view of flash pointrconsiderations, so that itrwillrbe more easily pump-J able'even at the very high solids content which is present.
  • the slurry is constantly agitated until used.
  • the fuel is mixed continuously at the rate at which it is used, so that it does not needrto be stored, although it may be prepared on a batch basis,
  • the fuel ispumped to the blast furnace,V
  • the slurry is injected directly into the hot air or blaststream which is blown into the furnace throughV the tuyeres, or is injected directly into the furnacethrough the wall proper. ⁇ If theoii comes into Vdirect contact with the'tuye're Wall, it tends to carbonize vsornevvhat at the prevalent high temperature, and for that reason it is preferred to inject the slurry into the tuyere opening lthroughV a lance, the slurry being injected into the blast stream substantially along thek axis of the tuyere so that it does not coat the tuyere Walls.
  • ⁇ the slurry can be introduced into the blast froman'opening in vlthe/top wall of the tuyere, where it Will be picked up by the blast and carried immediately into Vtheinterior of the furnace.
  • the fuel Will not burn sutciently for optimum operation, and if it is injected too far from the raceway, it
  • the drawing is a diagrammatic illustration ofthe.V
  • the coal incorporated in the slurry may be scalped olf volatiles in the coal which, with the carbon rnonor'rideV produced by the colte in the charge, reduces the ore.
  • Partial combustion kof the yhydrocarbon fuel produces carbon monoxide and, more importantly, hydrogen, which is several times more effective thanfcarbon monoxide ⁇ as a reducing agent.
  • the hydrogen which is produced from the burning oil and coal combines with the oxygen of the ore to 'formu/ater,v and thereby producesrhot metal.
  • an excess of hydrogen. is avail- ⁇ Y able forreducing the ore higher'lin the furnace, '1 minimizing hangupsfand permitting higher blast temperatures to be'used.
  • some unreacted hydrogen will be presentrin the top gas fromr thefurnace, which Will. en- 'f Vrich its heatingfvalue and improve the economics ofV the preheating operation.
  • the rate at whichjthe'fgiurry is added to the blast depends upon several variables, and cannot be concisely Y specified for any and all conditions. In general, the
  • the slurry was delivered to the blast furnace through a 11/2 pipe, and is preferably pumped by a Moyno Pump of the rotatingy screw type, made by the Mayno Pump Division of Robbins & Myers Company, Inc., of Springlield, Ohio.
  • the size of the uid conduit through which the slurry is delivered to the furnace appears to be fairly critical for any given slurry. If the pipe is too small in diameter, or is too long, an excessively high pressure will be required to force the slurry through it at a rate suicient to keep the coal particles from settling out; and if the pipe is too large in diameter, the velocity of fluid movement may be so low for a given pressure drop that the particles will settle out. In practice, for any given slurry there is a limited range of conduit sizes through which the slurry can be pumped With available pumping equipment and without the coal particles settling out.
  • the slurry can be introduced into each tuyere of the furnace through a 3%" or 1 lance.
  • the size of the lance will depend on the top size of the particles in the slurry. For example, if the top particle size is about 1/8, then a 3/M lance can be used, whereas if top particle size is 1A it is preferable to use 1 lance. It should be stated that the use of a lance in the tuyere does present the disadvantage of partly blocking the tuyere opening, which disadvantage is not encountered if the slurry is injected directly into the tuyere through an opening in its wall, or an opening in the blowpipe.
  • the velocity of the air blast at the tuyere is very high, typically about 3D0-600 feet per second, and the blast carries the pariculate slurry into the raceway of the furnace even though some of the particles are relatively heavy. Tests have shown that the coal particles do not settle out appreciably in the iiuid conduits, provided conduits of suitable size are used and provided the uid is constantly kept in motion.
  • the slurry provides more efficient and economic furnace operation, as previously explained.
  • the capacity of the furnace is increased, and hot metal is produced at lower cost.
  • the present invention has been described herein primarily in relation to the operation of a blast furnace, in which its primary utility is at present believed to reside.
  • the slurry produced in accordance with this process is quite suitable for use as a fuel in other types of furnaces, and it will be understood that it is not limited to use in a blast furnace alone.
  • the method which comprises, sizing coal to a maximum particle size of about j/1(; to 3/s, mixing said coal with a fuel oil having a viscosity in the range of about 75-1000 seconds S.F. at 122 F. to form an unstable slurry which consists essentially of Said coal and said oil and in which said coal is suspended in said oil, said coal comprising about ttl-70% by weight of said slurry and said oil comprising about 6030% of said slurry, heating said oil and maintaining it at a temperature of about ISO-300 F. as said coal is being mixed therewith, whereby the viscosity of said slurry is reduced, maintaining said coal in suspension in said slurry by agitating said slurry and keeping said slurry in movement, and introducing said slurry into a furnace.
  • the method which comprises, comminuting coal to a maximum particle size of about 1/16 to SAV', mixing said coal with a fuel oil having a viscosity in the range of about -1000 seconds SF. at 122 F. to form an unstable slurry in which said coal is suspended in said oil, said coal comprising about 40-70% by weight of said slurry and said oil comprising about 6030% of said slurry, heating said slurry to a temperature of about 15G- 300 F.
  • the method which comprises, preparing natural grind coal to a nominal size in the range of 1/16" x 0 to 1A x 0, mixing said coal with a fuel oil having a viscosity in the range of about 75-30() seconds SF. at 122 F. to form an unstable slurry in which said coal is suspended in said oil, said coal comprising about 50-70% by weight of said slurry and said oil comprising about 5-30% of said slurry, simultaneously heating said slurry to a temperature of about 1GO-250 F., maintaining said coal in suspension in said slurry by agitating said slurry and keeping said slurry constantly in movement, and injecting said slurry into the hot air blast of a blast furnace.
  • the method which comprises, sizing coal to a nominal size of about 1A X 0, the major portion of said coal being able to pass a No. 36 screen, mixing said coal with a fuel oil having a viscosity in the range of about -275 seconds SE. at 122 F. to form an unstable slurry in which said coal is suspended in said oil, said coal comprising about 55-65% by weight of said slurry and said oil comprising about l5-35% of said slurry, heating said slurry to a temperature of about,160-195 F. whereby the viscosity of said slurry is reduced, maintaining said coal in suspension in said slurry by agitating said slurry and keeping said slurry constantly in movement, and then pumping said slurry into the air blast of a blast furnace.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture Of Iron (AREA)
US168200A 1962-01-23 1962-01-23 Method of operating a blast furnace Expired - Lifetime US3157491A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE627469D BE627469A (xx) 1962-01-23
US168200A US3157491A (en) 1962-01-23 1962-01-23 Method of operating a blast furnace
DE19631433290 DE1433290A1 (de) 1962-01-23 1963-01-14 Verfahren zur Beheizung eines metallurgischen Ofens
GB1609/63A GB1025647A (en) 1962-01-23 1963-01-14 Improvements in and relating to operating furnaces
FR922195A FR1344768A (fr) 1962-01-23 1963-01-22 Procédés d'exploitation d'un haut fourneau
AT49063A AT262348B (de) 1962-01-23 1963-01-22 Verfahren zum Betrieb eines Schachtofens, insbesondere eines Hochofens
SE707/63A SE303774B (xx) 1962-01-23 1963-01-22

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US168200A US3157491A (en) 1962-01-23 1962-01-23 Method of operating a blast furnace

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US3157491A true US3157491A (en) 1964-11-17

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US (1) US3157491A (xx)
AT (1) AT262348B (xx)
BE (1) BE627469A (xx)
DE (1) DE1433290A1 (xx)
FR (1) FR1344768A (xx)
GB (1) GB1025647A (xx)
SE (1) SE303774B (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3406026A (en) * 1962-07-18 1968-10-15 Central Nat De Rech S Metallur Method of supplying blast furnace with solid fuel and oil suspension
CN110175716A (zh) * 2019-05-27 2019-08-27 中冶赛迪重庆信息技术有限公司 面向高炉出铁的状态变化及重量检测方法、设备及介质

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1507740A (en) * 1920-02-16 1924-09-09 Edmund B Kirby Method of operating blast furnaces and similar furnaces
US2938782A (en) * 1956-04-24 1960-05-31 Commw Engineering Corp Method and operation of blast furnaces and metallurgical fuels therefor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1507740A (en) * 1920-02-16 1924-09-09 Edmund B Kirby Method of operating blast furnaces and similar furnaces
US2938782A (en) * 1956-04-24 1960-05-31 Commw Engineering Corp Method and operation of blast furnaces and metallurgical fuels therefor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3406026A (en) * 1962-07-18 1968-10-15 Central Nat De Rech S Metallur Method of supplying blast furnace with solid fuel and oil suspension
CN110175716A (zh) * 2019-05-27 2019-08-27 中冶赛迪重庆信息技术有限公司 面向高炉出铁的状态变化及重量检测方法、设备及介质

Also Published As

Publication number Publication date
GB1025647A (en) 1966-04-14
SE303774B (xx) 1968-09-09
BE627469A (xx)
AT262348B (de) 1968-06-10
FR1344768A (fr) 1963-11-29
DE1433290A1 (de) 1968-11-07

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