US1482553A - Furnace oil blast - Google Patents

Description

Feb 5 1924.

C. A. GRABILL FURNACE OIL BLAST Original Filed Feb. 12. 1919 2 Sheets-Sheet 1 BY I M ATTORNEY Feb. 5, 1924,;

c..'A. GRABILL FURNACE OIL BLAST Original Filed Feb. 12. 1919 2 Sheets- R Q Q Q r'-' N %Fiw B ATTORNEY Patented Feb. 5, ieaa.

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CLARENCE ALFRED GRABILL, OF EL PASO, TEXAS, ASSIGNOR TO AIlIERICAN SMELT- ING & REEINING COMPANY, CORPORATION 01? NEW JERSEY.

FURNACE OIL BLAST.

Application filed February 12, 1919, Serial To all 111720-772 it may concern.

Be it known that I, CLARENCE ALFRED in-WILL. a citizen of the United States, and resident of El Paso. in the county of El Paso and State of Texas, have invented certain new and useful Improvements in Furnace Oil Blasts. of which the following is a specification.

The invention relates in general to an improvement in the operation of a blast furnace in certain metallurgical operations which either require, or are not deleteriously affected by. the addition of carbonaceous material to the ore charge in the furnace.

As an example of one such operation it is recalled that in utilizing a. blast furnace in the smeltingof certain ores, for instance, copper ores. accumulations known as crusts, or accretions and forming artificial boshes about the inner wall of the furnace above the molten charge. The presence of these aocretions is objectionable and efforts have been made to remove themby introducing carbonaceous matter, usually powdered coke together with an air charge, into the furnace content at the base of the artificial boshes. This coke charge even when introduced into the furnace from all sides thereof tended to move towards the center of the fusion zone and there formed an upwardly ascending combustion column having little effect on the large mass of the forming accretions adjacent the relatively cool sides of the furnace.

The invention conten'iplates the introduction into the furnace of carbonaceous matter but controls the admission of the same so as to prevent the formation of the boshes rather than to attempt their destruction after they are formed.

This result .11: attained by directing the carbonaceous n t er, together with suificient air to supp rt combustion, into the furnace in the form of a series of short, hot flames co-acting within the furnace to form a ring" of flame adjacent the inner wall of the furnace and at the fusion zone of the charge therein.

In. its commercially perfected form this objective is attained by atomizing liquid fuel, such as oil. just outside of the furnace interior and injecting the same .so as to form a flame which will start at the interior No. 276,591. Renewed September 26, 1923.

wall of the furnace but which will extend towards the center of the furnace only for a relatively short distance.

In this way there is formed a high temperatured combustion zone close to the portion of the wall just above the discharge ports of the usual air tuyeres and which zone does not reach to the center of the furnace.

In prior constructions where oil in liquid form was blown in through the tuyeres either with the blast or close thereto, it usually happened that part of the oil was not burned and ran dOwn the sides of the jacket or into the tuyeres where it caused av great deal of trouble about the furnaces. hen th tuyeres were opened for cleaning or barring the furnace, oil flames projected therefrom with resulting; danger to the workman and surrounding property.

Accordingly the invention features a construction in which the oil can be readily vaporized so that it can be completely burned without loss in fuel. and without danger to the adjacent property.

The peculiar requirements of this process necessitates a new form of furnace air tuyeres or rather a combined burner and tuyere which can use any available oil and accordingly the invention has for another object the providing of a burner capable of utilizing; cheap grades of crude oil in carryinc out the above outlined process economically on a large commercial scale.

Incidental to this last object it is a. further desidcratum to provide a burner which can be readily attached to conventional furnaces with the least possible change in the furnaces and their associated parts, and in which the usual air tuyere inlets may be utilized for the introduction of the fuel while permitting, if necessary, the continuation of their use as entrance ports for the admission of part or even all of the air necessary to effect the smelting or other op-. erations taking place in the furnace.

Various other objects and. advantages of the invention will be in part obvious from an inspection of the accompanying: drawings and in partwill be more fully set forth in the following; particular description of one form ofmechanism embodying my invention, and the invention, also consists in cerinches is suggested as outside limits.

tain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the accompanying drawings:

Figure l is a view in right end elevation of afurnace looking at the same in the direction indicated by the arrow in Figure 2, equipped with a preferred embodiment of my invention and with parts thereof broken away to show internal construction; and

Figure 2 is a view in side elevation of the device shown in Figure 1.

In the following description and in the claims, parts will. be indentified by specific names for convenience of expression but they are intended to be as generic in their applicalion to similar parts as the. art will permit.

In the accompanying drawings there is shown a blast furnace of conventional form used for smelting copper ore and the like, and equipped with the usual'battery of air tuyeres 11 which are spaced apart .circumferentially of the furnace adjacent the bottom thereof and designed to supply air to the furnace under the usual pressure of ten to fort-y ounces per square inch.

The furnace is provided with burner receiving openings 12 which are preferably formed. by open end tubes 13 extending through the water jacket 14. This arrangement permits of the mounting of burners in. the tubes, so. that. the burners will be protected from the heat of the furnace on all sides except the front. These openings are positioned above, and preferably between, the tuyere 1 1 which arrangement has both mechanical and metallurigicaladvantages. The distance between the level of. thetuyeres and the level of the openings 12 will vary with the type of furnace, the charge under treatment and other controlling factors, but a distance of six to thirty Fifteen to twenty-seven inches distance has been used with satisfaction in one type of furnace. .Oil vaporizing burners 15 are demountably positioned in each of these openings in the: device illustrated but from four to twelve burners in active operation will be sufiicient in the usual operations and are SOi mounted as to prevent the escape of air and oil.from the interior of the furnace.

These burners are so designed that they w1ll..atomize. the particular grade of oil supplied 'thereto. and will produce a relativelyrshort butintensely hot flame. The flame preferably should be-only a few inches in lengthstarting a short distance to the outside of the inner, wall 16 of the furnace and extending. into the interior furnace. onfining thencombustion zone of burning gases to theouter side of the charge leaves the center ofthe chargeopen to receive the air passed upwardly through the center of the charge from the usual tuyeres. The

oil for supplying the burners is contained in an oil tank 17 in which the oil is under a working pressure of 50-10O pounds per square inch. From the tank the oil is passed through one or more main pipes 18 from which pipe each burner is supplied by laterally extending branch-pipes l9. Vi here the oil is too heavy to flow through the pipes without undue friction or too heavy to be readily vaporized, it is heated toatemperature sufficiently high to insure an easy flow. In one instance a temperature of 225 F. has proven satisfactory with a low grade of crude oil at 14: Baum. The oil is heated inthie instance by means of a steam pipe (not shown) coiled inside the main oil feed tank 17 and by a steam pipe 20 encircling the main pipe 18.

The ordinary air supplied to the air tuyeres is not under sufficient pressure to satisfactorily vaporize the heavier oils and therefore the burners are supplied with air from another source under a relatively high pressure. In the case above suggested a pressure of -100 pounds per square inch has been found necessary to vaporize the heavy oil effectively. The air is supplied from a suitable source 21 and leads by sep arate branch air pipes 22 to each of the burners. In the practical operation of the device, the best results are obtained by supplying an amount of air to the burners insufhcient to assure the complete combustion of the amount of oil discharged per unit of time. This rich fuel charge insures that the oil charge in its vaporized form will be admitted into the interior of the furnace before it can be subjected to complete combustion by the air from the air tuyeres. In order to insure this balancing of air to fuel, air metering devices 23 are positioned in each of the branch pipes :22 and oil metering devices 2 are positioned in each of the oil branches 24. These separate controls insure an accurate regulation of each indi vidual burner, but it is of course obviously within the scope of this invention to control the entire oil and air supply from one metering device positioned at some convenient place in each of the supply systems preferably adjacent the source of these supplies.

Referring to certain refinements of construction it may be noted that under some circumstances it is desirable to withdraw one or all of the burners and seal the openings as is usual infurnace practice. In order to facilitatethe ready withdrawal of the burn ers the supply pipes contain readily separable couplings 25 which permit the burners to be with drawnand disposed in an inoperative position. ready to be again inserted into the openings when desired.

\Vith the furnace in active operation as is usual andassuming that there is being conducted a metallurgical process which refit.

quires the addition of fuel, it is obvious that the entire amount of fuel necessary to the process may be introduced in the form of the vaporized oil from the burners. However, it has been found in practice that bet ter results are attained by reducing the amount of coke or other usual solid fuel from 5()75% and to substitute an amount of oil necessary to compensate for this reduc tion in the amount of coke or other solid carbonaceous material. With. the oil supply thus regulated to give the necessary amount of fuel to the charge the oil is atomized by the air under the relatively high pressure necessary to effect the atomization and to maintain the flame even in the presence of cooling ore adjacent the inner end of the openings into the furnace. The air supply is regulated so that it will not provide the amount of oxygen necessary to effect a complete combustion of the oil before it is fully discharged into the interior of the furnace. In the adjustment of the supplies to the burner, care is exercised that the flame from the burners project into the furnace but for a few inches and to form, in efiect, a substantially uniform zone or a closed circle of extremely hot flames close to the inner wall of the furnace; at the fusion zone of the charge therein and below the point where the accretions usually begin to form in such furnaces.

The operation is continued in accordance with the usual practice as if a coke charge were introduced instead of the vaporized oil.

By means of a device of this character it is possible to maintain an intense zone of heat above the air tuyeres and close to the otherwise cool surface of the furnace and in this way the formation of accretions is effectively prevented. Further, it is possible to economize in the use of coke or coal which is diflicult to obtain in some locations. The liquid oil is utilized in the device disclosed without the objection which has heretofore marred the uses of liquid hydrocarbons in smelting plants.

Having thus described my invention, I claim 1. In the operation of a blast furnace, the process which consists in forming a ring of burning carbonaceous fuel confined to a position adjacent the inner wall of the furnace and at the fusion zone of the charge within the furnace thereby to prevent the formation of accretions on the sides of the furnace while permitting a free draft up the center of the furnace interior.

2. In the art of smelting in a blast furnace, the process for preventing the formation of accretions in the furnace, which process includes the step of maintaining a ring of burning fuel at the place in the furnace adjacent the place where the base portion of the accretions usually form when.

the furnace is operating normally and while maintaining said ring spaced from the vertical central axis of the furnace thereby to permit the free entrance of air to the charge of ore under treatment in the furnace.

In the operation of a blast furnace, the process which consists in directing a relatively short, hot flame through the side of the furnace at the point where the base of the bushes usually appear in the usual smelting operations and regulating said flange so that it will have a length materially less than the radius of the furnace interior.

4. In the art of smelting ores which usually require the addition of a fuel such as coke, the process which consists in blowing air under relatively low pressure through the charge as is usual with the coke charge, reducing the amount of fuel necessary to effect the desired operation and supplyingthe shortage of solid fuel by introducing into the furnace under relatively high pressure an amount of l quid fuel in atomized form sufficient to mat-t with the solid fuel present to furnish the necessary amount of fuel said atomized fuel being of a reducing character as it is passed into the furnace.

5. In the art of smelting ores, the process which consists in blowing air through the charge as usual and simultaneously causing atomized liquid fuel to pass into the charge by means of a current of air under high pressure, said atomizing air current being in an amount insuflicient to support the combustion of the liquid fuel whereby unburned particles of fuel are conveyed to the charge there to combine with the air in the usual blast and said air current being insufficient to project the flame of combustion of the atomized fuel to the center of the furnace interior.

6. In the art of smelting ores. the process which consists in forming a stream of atomized oil with an amount of air insufficient to insure the complete combustion of the oil present and introducing said atomized oil stream into the smelting furnace adjacent the fusion zone of the ore charge therein.

7. In the art of smelting ores, the process which consists in forming a stream of atomized oil with an amount of air insufficient to insure the complete combustion of the oil present and introducing said atomized oil stream into the smelting furnace adjacent the fusion zone of the ore charge therein and into an air stream sufficient to insure the complete combustion of the oil present.

8. In the art of smelting ores, the process which consists in forming a stream of atomized oil with an amount of air insufficient to insure the completecombustion of the oil present and introducing said atomized oil stream into a charge of burning ore and in the presence of an amount of air sufficient to support the combustion of both the ore charge and the oil.

9. In the art of smelting ores, the process which consists in subjecting the charge to the action of the usual air draft having a pressure of 10-t0 ounces per square inch and simultaneously injecting vaporized oil into the furnace with air under a pressure of 50-l00 pounds per square inch, said two air supplies cooperating to supply air to effectthe desired sineltinp operation and to support the combustion of the oil.

10. A furnace provided with an air tnyere adjacent the bottom thereof and with an opening through. the side of the furnace, spaced above said air tuyere and at a level which will bring it adjacent the fusion zone of the charge in the furnace and a den'iountable oil atomizing burner adapted to be inserted in said opening, said opening designed to be closed when the burner is deniounted therefrom in the different operations of the furnace.

11. A furnace provided with an air tuyere adjacent the bottom thereof, a burnor above the tuyere for introducing atoniized liquid fuel into the interior of the furnace and at a level adjacent the fusion zone of the charge in the furnace and metering means for regulating the flame from said burner thereby to produce a short, hot flame confined to a position adjacent the inner Wall of thcfurnace and spaced from the center of the furnace whereby the flame will be concentrated at the fusion zone of the charge and close to the Wall of the furnace.

12. A furnace prorided with an air tuyerc adjacent the bottonr thereof and an opening into the furnace above said tuyere, an oil burner positioned in said opening and spaced outwardly from the inner end there of whereby a flame may be started into the furnace interior from a point exteriorly of the combustion zone of'the charge in the furnace and a mounting for said burner for permitting the Withdrawal of the same from the opening.

Signed at San Luis Potosi, Mexico, this 21st day of January A. D. 1919.

CLARENCE ALFRED GRABILL.

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