US2633332A - Flame process - Google Patents

Description

March 31, 1953 .1. J. MU-PHY ET A1.

FLAME PROCESS Filed Nov.- 8,'1946 INVENTORS JOHN J. MURPHY JOHN M. GA/NES EDWARD L MOCANDLESS ATToRNEY Patented Mar. 31, 1953 FLAME PROCESS John J. Murphy, Pelham, John M. Gaines, Buffalo, and Edward L. McCandless, Kenmore, N. Y., assignors, by mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York Application November 8, 1946, Serial No. 708,758

8 Claims. (Cl. Z55- 1.8)

This invention relates particularly to improved means and components for generating and controlling high-temperature flame and its localized elective application for predetermined removal of material from solid hard and refractory masses such as rock or rock-like bodies, with or without metal reinforcement, or such as metal bodies. Exemplary, but not limiting, purposes of such predetermined removal are for making holes in or through, for gouging, severing, or desurfacing of, such bodies.

An object of the invention is to increase the economic advantage of such removal thermally as against any presently known alternative removal mechanically. The invention will be described in greater detail as it may be applied for working rock and mineral-like masses by piercing deep holes therein to be charged with explosives.

Rock has been thermally worked heretofore with an oxyacetylene flame cooperating with burning particles of free metallic material. However, While such a gas flame has been satisfactory for some operations, it is not equally suitable to meet the requirements under other conditions. For example, safety codes do not permit acetylene to be used at very high pressures, and the combustion of low pressure acetylene does not produce gaseous products of combustion at pressures lsufliciently high to remove detritus from a very deep hole without supplemental ejection uid. Also, when employing an Oxy-acetylene flame for piercing a hole by the process of melting, quenching with water, and disintegrating rock, disclosed in Patent 2,327,496, the depth of hole pierced in a downward direction is limited because water tends to accumulate in the bottom of the hole and extinguish the Oxy-acetylene flame. When `metal powder is used with an Oxy-acetylene flame, as has been proposed, the combustion of metal powder does not increase the gas pressures available for the removal of detritus or water because it burns to a solid oxide rather than to a gas.

Among the objects of the present invention are: to produce a name for heating a body and simultaneously apply thereto more effectively particles of material, such as powder; and to provide for carryingv powdered material positively, continuously, and uniformly to a locality where it is to be used in conjunction with a flame. Other objects are to provide a novel method for thermally working rock whereby there is produced a large volume' of gas for ejecting detritus; whereby deep holes can be successfully pierced in a downward direction; whereby water-.will be prevented from extinguishing a flame in a hole; whereby fuel can be delivered to the bottom of a hole positively at a relatively constant delivery pressure regardless of pressure variations in the hole and whereby thermal rock working will proceed safely, rapidly, and economically. Another object is to reduce the cost and eliminate some of. the diiculties `of shipping to relatively inaccessible localities the fuel required for thermal rock piercing.

`Other objects are to provide novel mixtures of liquid fuel with powdered materials; .to provide such mixtures which have improved stability of powder suspension, yet can be easily pumped; and to provide such a mixture whereby name stability is assured even when water accumulates in the vicinity of the ame.

How the above and other objects are attained will become apparent from the following description, having reference to the accompanying drawing, wherein:

Fig. 1 is a side elevational view, parts being in section, showing schematically an arrangement of apparatus for piercing a hole in rock by the method of the invention; and

Fig. 2 is a longitudinal sectional view of a blowtorch suitable for piercing a hole in rock by the method of the invention.

In one specific embodiment of the method of the present invention a rock is thermally pierced, cut, or otherwise thermally worked by applying thereto a localized high temperature flame resulting from the combustion of a iiowable nongaseous fuel in an oxygen rich atmosphere, thereby separating material from the body of rock by the heating effect of the flame. The process is operable on many kinds of rocks and .mineral masses, for example hematite iron ore, taconite iron ore, and concrete. Many flowable nongaseous fuels can be used satisfactorily, but combustible liquid hydrocarbons such as various petroleum fractions are preferred. It is also pre.- ferred that the liquid fuel contain a jellying or pasting agent. Among the suitable fuels are jellied kerosene, jellied gasoline, kerosene, fuel oil, crude oil, petroleum tars and coal tars and semifluid asphalte, used crank case oil, and solutions of polymers such as polystyrene or polyisobutylene in an aliphatic hydrocarbon such as kerosene or an aromatic hydrocarbon such as xylene.

J ellied fuel-s can be prepared in ways well known in the grease art, using a .small amount of one or more ,iellying agents such .as the common soaps comprising alkali or alkaline earth those situations where no water-reactivematerial Y is to be mixed with the fuel.

Such liquid fuels provide important advantages not provided by acetylene at customary pressures. They burn to form much larger volumes of gaseous products of combustion which act toward ejecting the detritus loosened from the rock mass by the flame because liquid fuels can be supplied at such high pressures that many more pounds ,of fuel can be pumped through a given flame port with a given head pressure per unit of time than is possible with relatively low pressure acetylene. They can be pumped to a combustion zone at a constant rate of flow because they are not aected by pressure variations in a hole. They are relatively inexpensive, and they can be transported to a remote locality in drums or vtank cars at a relatively low cost for the quantity of heat available.

Although it is especially advantageous to burn the flowable non-gaseous fuel in substantially pure oxygen, which gives a llame of high ternperature and heating inten-sity, the method can be operated using oxygen mixed with other gases as long as the proportion of oxidizing gas is high enough to give a flame having sufficient heating intensity to cause material to separate from the rock body.

An additional important feature of the present invention is that particles of solid powdered material adapted to aid the separation of rock can be incorporated in and dependably carried by a stream of liquid fuel to the locality Where an oXy-fuel flame is being applied to the rock. In some instances the solid powder can be a preformed flux active to modify the composition of the removed rock. In other instances it can be a combustible powder which augmente the heat of the burning liquid fuel, and additionally may be of such a character as to change composition and form a flux upon combustion, or as -to form a large volume of gaseous products of combustion to assist in blowing detritus from the locality of flame application. Whatever the powder, it advantageously should be line enough y to pass an 80 mesh screen (U. S. Standard).

Such preformed powdered iluxes as calcium oxide, calcium carbonate, borax, and sodium carbonate can be suspended in liquid fuel and applied against a body of rock concurrently with a flame to combine with melted rock and assist in the formation of a highly iiuid slag which is friable after quenching. Such combustible nuxforming fuel powders as ferromanganese and aluminum also can be suspended in liquid fuel and burned to oxides which combine with melted rock and form a iluid slag. Such solid fuels as powdered coal, carbon black, or other forms of carbon can be suspended in liquid fuel and burnedl to provide both intense heat and large volumes of gas to assist in removing detritus. Sometimes the best results are obtained by mixing together in the liquid fuel two or more powders from the three categories described above. Some powdered materials may melt in the flame and be in the liquid condition when they strike a body of rock, but generally the h-ot particles are solid.

J ellied combustible hydrocarbon liquids such as jellied gas-oline and kerosene are superior to many other liquids for suspending and conveying powders. Jellied fuels provide the optimum combination of powder suspending ability and good pumping characteristics. In such jellied fuels, for example, powder settles out of suspension only very slowly, and even when it has linally settled the cake in the bottom of the container is loose and easily stirred back into suspension. Furthermore, the viscosity of a jellied hydrocarbon does not change greatly with changes in temperature. If the proportions of powder and liquid fuel are such as to give a stable paste, no jellying agent need be added but pumping is somewhat harder.

Although the fuel stream has certain advantages for carrying the powdered flux or fluxforming fuel, it is apparent that the powder also can be introduced to the reaction zone in other ways, as in the oxygen stream or independently of both the oxygen and fuel streams.

In the following description, all pressures inentioned are gage pressures.

The method of the invention will be described more specically with reference to Figs. 1 and 2 of the drawing, by Way of example, as applied to the piercing of a deep horizontal hole in a body of roel: by a rock melting, quenching, and disintegrating procedure. Fig 1 shows a long blowtorch l on a carriage I3 which is moved along a support ifi lengthwise of the torch by a lead screw Il. Blowtorch Il comprises a non-rotating internal llame-producing unit i9 upon which is rotatably mounted a long sleeve 2l having reamer teeth 23 adjacent its forward end. Carriage I3 has a motor 25 acting through a suitable drive to rotate the sleeve 2l and. reamer teeth 23 in a hole 2'! being pierced in a body oi roel.` R. Internal flame-producing unit I9 is restrained from rotation by exible supply conduits 29, 3l, and 33 for water, oxygen, and liquid fuel, respectively, coupled to the rear body 3f! of the blowtorch. The apparatus outlined above is described in greater detail in United States Patent 2,327,496 granted in the name of Charles J. Burch on August 24, 1943.

A stream of liquid fuel is supplied to a central tube 35 in the blowtorch l l by conduit 33 which is connected to a liquid reservoir or container 4l through a liquid pump 31 of any suitable type, such as a three-stage screw type pump driven .by a motor and gear reducer unit 39 and building up a pressure of 25-50 lbs/sq. in. Forcing of the liquid also can be eected by other pumping devices, such as an hydraulic displacement chamber or a piston type pump. When powdered material is to be suspended in the liquid fuel in proportions other than those forming a stable paste or jelly, the mixture or slurry of powder and liquid fuel in the reservoir lll is agitated continuously in the reservoir to keep the powder particles in suspension. Agitation of the liquid fuel can be accomplished in any suitable way, as by a propeller type agitator 45 driven by a small lmotor 4l clamped upon the top edge of the reservoir 4I.

When piercing a hole 27 in a rock body R by a melting, quenching, and mechanical disintegrating procedure, the pump 31 is operated continuously to force liquid fuel from the container di to and through the central tube 35 of the blowtorch il. Oxygen is supplied to the conduit 3| from any suitable source, passes through an annular passage 49 surrounding tube 35, and is discharged from a tip 50 at the front of the blowtorch through a plurality :of forwardly and inwardly converging discharge ducts 5l `arranged in a circle around the central tube in such a Way that a plurality of oxygen jets impinge outside of the blowtorch against the central stream of liquid fuel from the tube 35 to form, upon ignition, a large bushy intensely hot flame.

Upon applying the flame to the face F of the rock body R, material is separated from the rock either by melting off, by spalling oi in an unmelted condition, or by a combination of melting and spalling, and passes from the vicinity of the ame'under the influence of gravity and/or the action of the gaseous products of combustion to leave a shallow cavity as the initial portion of hole 2l. The tip of the blowtorch Il is advanced progressively into the cavity and into successively formed portions thereof as it becomes deeper.

Water is supplied by conduit 29 from any suitable source to a second annular passage 53 in the blowtoreh surrounding the annular passage B9. The water cools the blow-torch by passing forwardly through passage 53, and is then discharged laterally from the tip into hole 2l through a plurality of annularly arranged ports 55 in front of the reamer teeth 23. Only a small ilow of water is required initially, but the flow is l .increased af-ter the hole is sufficiently deep to form an enclosed combustion rone for the flame. When the water flow is increased the water quenches and solidifles any molten slag separated from Vthe rock by the flame, and the quenched slag is mechanically disintegrated in the hole yby physical impact with the rotating reamer teeth 23. The pieces of disintegrated slag then are blown from the hole 21 by the gaseous products of combustion of the liquid fuel and of any solid carbonaceous fuel particles which may have been suspended in the liquid fuel, as well as by the large volumes of steam formed by evaporation of water in the hole.

Suilciently large volumes of gaseous products of combustion are formed in the procedure described above to blow Water out of even a deep downwardly directed hole, thus preventing accumulation of enough water to extinguish the flame. such downwardly directed holes only to a limited depth by the melting, quenching, and disin-tegrating technique becausewater would accumulate in the h-ole and extinguish the ame.

Ordinarily it is considered hazardous for substantially pure oxygen to contact oil or other liquid fuels in commercial operations, but the method of this invention is such that the hazard is substantially eliminated lby keeping the liquid fuel and oxygen separate from one another until they are actually discharged from the tip of the blowpipe. Thus, the mixture of oil with oxygen occurs outside of the blowpipe in the zone where combustion is desired.

In the rook melting, quenching, and disintegrating procedure described above it is important that the slag be very iiuid when molten so as to flow freely from the vicinity of the flame, and that it be very friable when quenched and solidied so as to be readily disintegrated by the reamer teeth 23. Some rocks inherently possess these characteristics, but with other rocks it is important to introduce with the flame iuxing powder which will unite with the melted rock to form a fluid yslag which is friable when quenched. f

It has heretofore been possible to pierce l '6 .Holes have beenY successively pierced by the method described above in large 'bodies of concrete, Sudan iron ore (predominately hematite), and taconite iron ore; Taconite comprises .alternate layers, in some of which magnetite predominates yand in .others of which silica predom inates, and is to some extent self-fiuxing. In a typical taconite iron ore the average composition was 40% FesOiand 54% SiOe, but the alternate layers varied from about 1F'e304 toabout 15% Fe304. Therefore, when kpiercing a hole in taconite iron ore transversely of the layers, any flux or flux-forming composition used must be ldesigned to give lthe lbest compromise results between piercing in FesOi and piercing in SiOz. Due to the high silica content of taconite iron ore the Oxy-fuel flame is maintained hot enough and of sufficient heating intensity to v.cause a substantial portion of the rock, estimated as 20-60% to be spalled ofi from the rock body and blown from the hole without ever fusing in the hole. Such spelled particles may be as large as one inch across.

Many liquid fuels can be used in performing the method, and they may be quite pasty in consistency or relatively free-flowing. When a liquid fuel is augmented by the addition of powdered material thereto, the constitution of the parti-cular rock to be thermally Worked will determine the character of the pow-der used, especially when a composition modifier such as a preformed flux, or a substance such as combustible flux-forming material which burns to form a composition modifier, is employed. Examples of typical powder-laden liquid fuels, which have been used successfully for piercing holes in taconite are as follows, proportions Abeing expressed as percentages by weight:

l. '7.3% Al powder, 8% grease, 19% diesel oil.

2. 50% jellied kerosene, 50% CaO or CaCOs powder.

3. 27% mineral oil, '73% FeMn powder.

4. mineral oil, 20% coal powder.

5. 40% jellied kerosene, 20% coal powder, 40% FeMn powder.

6. '70% jellied kerosene, 30% borax powder.

7. 29% mineral oil, 35.5% Al powder, 35.5% Mg powder.

8. 43% jellied kerosene, 9% coal powder, 48% NazCOs powder.

9. 50% jellied kerosene, 50% CaCz powder.

Commercially pure calcium carbide powder (CaCz) carried in the fuel is surprisingly effective because it has several important properties not possessed by most powders. First, calcium carbide very effectively prevents extinction of the flame because it reacts with water to produce acetylene gas which b urns in the hole. Further, the solid end products have a fluxing action on some melted rocks to form a `fluid slag which is friable after quenching. Additionally, at least part of the calcium carbide is believed to burn in oxygen and liberate a large quantity of vheat while forming a flux as a product of combustion. The calcium carbide powder is effective in any amount vbut desirably should constitute between 5% and 50% by weight of the fuel-powder mixture; and it can be used alone in the liquid fuel, or can be used in conjunction with other powders vto give the optimum results. For example, when large quantities of calcium oxide are required to flux the rock it is economical to suspend in the liquid fuel a mixture of particles of relatively inexpensive calcium oxide with just enough'of the relatively expensive calcium carbide particles to prevent extinction of the flame by water.

Other powders which are the equivalent of calcium carbide are sodium acetylide, aluminum carbide, sodium, potassium, lithium, and hydrides Vof the alkali and alkaline earth metals. All of these except aluminum carbide and sodium acetylide generate hydrogen upon reaction with water. Aluminum carbide generates methane, sodium acetylide acetylene.

Liquid fuels such as kerosene, fuel oil, and the others named herein are especially advantageous for conveying the above-mentioned water-reac- 'tive powders because they protect the powders from contact with water, thus preventing premature deterioration. If such powders were carried in a moist gas stream, they would be prematurely slaked to come extent by the water vapor in the gas.

In a specific example of rock piercing by the improved method, a blowtorch six inches in diameter (including the reamer teeth) pierced a hole thirty feet deep vertically downward in 'taconite iron ore at a rate of 2.5 in./min., using tween 61/2 and 9 inches, but a heavy hardened slag lining reduced the effective diameter to slightly more than 6 inches.

From the foregoing detailed description it is evident that there are several fundamental features of our novel process whereby deep holes can be pierced in a downward direction in mineral materials such as iron ore. One is the positive and uniform delivery of fuel to the reaction zone at a very high rate and at a relatively constant delivery pressure high enough to give rapid and efficient ejection of detritus regardless lof Variations of the pressure within the hole. Preferably the fuel pressure and iiow rate should be high enough to produce a combustion pressure greater than lbs/sq. in. at the bottom of a hole, so that the fuel pressure must exceed the combustion pressure to insure continuous flow into the progrossing reaction zone. Another essential is the use of a high pressure ejection uid, preferably steam generated by discharging cooling water from the blowpipe onto the molten slag in the hole. Another important feature where a very high rate of heat transfer to the rock is desired is the use of a metal powder as an auxiliary fuel. Where the rock is not self-iiuxing, it is also imperative to use vigorous uxing agents, either delivered to the piercing zone as preformed fluxes, vor as the combustion products of appropriate combustible metal powders. Such fluxes should be selected to give a highly uid slag which is easily friable after quenching.

The method of the invention has been described speciiically above, by way of example only, as applied to the thermal piercing of holes in rock. It is to be understood that the principles of the invention can be applied quite generally where a body of material is to be heated and hot particles of material are to be applied simultaneously thereto, and especially where the comiposition of such a body of material is to be 8 modified by contacting it with hot particles of a composition modifier while heating the body.

Although specic embodiments of the present invention have been described in detail, it is apparent that changes in the method and changes in the construction and relative arrangement of parts of the apparatus can be made within the spirit of the invention and within the scope of the claims appended hereto.

We claim:

l. In the method of working rock by progressively applying thereto flame from the combustion of a liquid fuel discharged from a blowtorch to separate material from said rock while water concurrently enters the vicinity of said flame, the improvement which comprises: directing into the water in the vicinity of said flame a nowing stream of particles of calcium carbide to generate acetylene, whereby such acetylene is generated, burns, and improves the stability of said flame.

2. In the method according to claim 1, said calcium carbide being carried into the vicinity of said name by said liquid fuel.

3. A fuel mixture comprising a liquid hydrocarbon fuel having mixed therewith and suspended therein particles of commercially pure calcium carbide in an amount between 5 and 50% of said mixture by weight.

4. A fuel mixture comprising a liquid hydrocarbon fuel having mixed therewith and suspended therein particles of commercially pure calcium carbide and particles of calcium oxide, said carbide and oxide together amounting to between 5% and 50% by weight of said mixture, and said carbide being at least 5% of said mixture.

5. In a method for working rock by applying thereto name, and separating material from said rock by the heating effect of said flame, the

improvement which comprises: forming said' flame by separately conveying to a combustion zone streams of water, oxygen, and a liquid fuel mixture comprising a liquid hydrocarbon fuel having mixed therewith and suspended therein particles of commercially pure calcium carbide in an amount between 5% and 50% of said mixture by weight, impinging said oxygen against said liquid fuel in said combustion zone to form a combustible mixture, igniting and burning said combustible mixture, and directing said water into said combmtion zone to react with said calcium carbide particles and form combustible acetylene gas.

6. in a method for working rock by applying thereto flame, and separating material from said rock by the heating effect of said flame, the improvement which comprises: forming said flame by separately conveying to a combustion zone streams of water, oxygen, and a liquid fuel mixture comprising a liquid hydrocarbon fuel having mixed therewith and suspended therein particles of commercially pure calcium carbide and particles of calcium oxide, said carbide and'oxide together amounting to between 5% and 50% by weight of said mixture, and said carbide being at least 5% of said mixture, impinging said oxygen against said liquid fuel in said combustion zone to form a combustible mixture, igniting and burning said combustible mixture, and directing said water into said combustion zone to react with said calcium carbide particles and form combustible acetylene gas.

'7. A method in accordance with claim 5 wherein said oxygen and liquid fuel are delivered to REFERENCES CITED The following references are of record in the iiie of this patent:

UNITED STATES PATENTS Number Name Date Re. 16,948 Becker May 1, 1928 Re. 22,964 Burch Jan. 20, 1948 65,677 Johnson et al June 11, 1867 219,181 Smith et al Sept. 2, 1879 609,067 Woltz Aug. 16, 1898 968,350 Harrison Aug. 23, 1910 1,005,640 Gardner Oct. 10, 1911 Number 20 Number l0 Name Date Mitchell Nov. 18, 1913 Stolle et al. Apr. 11, 1916 Greenstreet Feb. 3, 1920 Bates Sept. 6, 1921 Schreiber Feb. 7, 1922 Greenstreet Oct. 10, 1922 Malcher May 13, 1924 Winckler Nov. 20, 1934 Ness Nov. 21, 1939 Burch Aug. 24, 1943 Burch Aug. 24, 1943 Miller et al Nov. 7, 1944 Aitchison Jan. 8, 1946 Burch July 2, 1946 Gaines Feb. 17, 1948 Williams Feb. 17, 1948 Cooke et al. July 20, 1948 FOREIGN PATENTS Country Date Great Britain 1922 Great Britain Oct. 21, 1926

Claims (2)

1. IN THE METHOD OF WORKING ROCK BY PROGRESSIVELY APPLYING THERETO FLAME FROM THE COMBUSTION OF A LIQUID FUEL DISCHARGED FROM A BLOWTORCH TO SEPARATE MATERIAL FROM SAID ROCK WHILE WATER CONCURRENTLY ENTERS THE VICINITY OF SAID FLAME, THE IMPROVEMENT WHICH COMPRISES: DIRECTLY INTO THE WATER IN THE VICINITY OF SAID FLAME A FLOWING STREAM OF PARTICLES OF CALCIUM CARBIDE TO GENERATE ACETYLENE, WHEREBY SUCH ACETYLENE IS GENERATED, BURNS, AND IMPROVES THE STABILITY OF SAID FLAME.

3. A FUEL MIXTURE COMPRISING A LIQUID HYDROCARBON FUEL HAVING MIXED THEREWITH AND SUSPENDED THEREIN PARTICLES OF COMMERICALLY PURE CALCIM CARBIDE IN AN AMOUNT BETWEEN 5 AND 50% OF SAID MIXTURE BY WEIGHT.

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