US1411072A - Apparatus and method of distributing pulverized coal in blast-furnace work - Google Patents

Description

R. A. WAGSTAFF.

APPARATUS AND METHOD OF DISTRIBUTING PULVERIZED COAL IN BLAST FURNACE WORK., APPLICATION FILED 050.4, ms.

1 ,41 1 ,072, Patented Mar. 28, 1922.

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HOPPER FOE H/LVER/ZEDGUAL BLAST FURNACE AIR MAIN LOW PRESSURE i3 AIR LINE lfl-l/GH PRESSURE AIR' LINE 8 com.

suPPLv 17 HP INJECTOR TUYERE FLOOR L/IVE R. A. WAGSTAFF.

. APPARATUS AND METHOD OF DISTRIBUTING [EULVEBIZED COAL INBLAST FURNACE WORK.

APPLICATION mzomc. 4. 1919.

Patented Mar. 28, 1922.

UNITED STATES,

PATENT OFFIC E.

RICHARD A. WAGSTAFF, or SALT LAKE CITY, UTA afs'sIGfioR To SMELTING AND REFINING COMPANY, OF

on NEW JERSEY.

NEW Yonx, N11, A coitromnon APPARATUS AND METHOD or DISTRIBUTING reLvEmzEn count BLAST-FURNACE WORK;

Specification of Letters Patent. Patented Application filed December 4, 1919.- Serial N6. 342,893.

To all whomz't may concern: I

Be it known that I, RICHARD A. WAG- STAFF, a citizen of the United-States,and resident of Salt Lake City, in the county of Salt Lake and State of Utah, have invented certain new and useful Improvements in Apparatus and Methods of Distributing Pul-' verized Coal in Blast-Furnace 'lVork, of which the following is aspecification- The invention relates to an improved method for preparinga carbonaceousfuel and for feeding the same to a blastor other 'metallurgical furnace; andfthe invention further relates to an improved instrumen-' tality for practicing the method.

It has been appreciated, heretofore that in certain metallurgical operations it is desirable to introduce fuel in a semi-gaseous'dry condition into a blast furnace for instance, by'pulverizin'g solid fuel and feeding the. pulverized fuel .to the-injector twyers by means of which the more or less diffused fuel was scattered into theinterior of the furnace. The air pressure on'the twyers, however, is usuall qulte h1gh,'due to the necessity of supplying sufficient oxygen-to sup-,

I of the invention is to provide a-preformed carbonized fuel characterized by the fact that each fine particle of carbonaceous par ticle is surrounded by an envelope of air and in which the body of prepared fuel can be fed to the twyers in the manner in which the solid stream of pulverized. fuel has heretofore been fed to the twyers. The present invention contemplates the economic formation-ofthe'carbonized fuel which is further characterized by extreme minuteness of the particle of the solid fuel and in'which the particles are uniformly scattered in the air present. In other words, the invention features the formation of a nebulous cloud of.

carbonaceous material'which can be ejected i in this form into the furnace byfhigh pres sure air.

Referring to the mechanical. features; of V the disclosure, one of the objects of thisphase of the invention is to provide a sim leand' economically actuated device for. orming the peculiar character of fuel'hereinbeforei outlined, and for maintaining the fuel in it diffused condition until itisdischarged into-the combustion zone of the furnace.

Another object of the invention featuring simpliclty of construct-ion and economyin operation is to provide such a device as'can be used as i an attachment to conventional V blast furnace plants; and which can utilize the sources of air pressures present in; con-.

ventional plantsv of this character.

Various other objects and advantages f of the invention will be in part obvious from .an inspection of the accompanying draw ings and in part will be morefully set forthin the following particular description of' one form of mechanism embodying .myin- 'vention, and the invention also consists in certain new and novel features of construction and COIIlblIltLtlOIT of parts hereinafter set forth and claimed.

Referring to the accompanying drawings:

Figure 1 is a diagrammatierepresentation in elevation of a plant organized to practice the method herein disclosed, but. it is to be understood that the elements illustrated are merely suggestive of one perfected means for practicing the method;

Figures 2 to 4, inclusive, are enlarged detailed views of the coal distributorshown in Figure 1; Figure 2 being a horizontal sectional view taken on the lines 22 of F igures 1 and 4; Figure 3- being a plan view looking down upon the coal distributor with its cover removed; and Figure 4 being a vertical sectional View taken axiallythrough" the distributor and on the line 4-4 of Fig-. ure

Figures 5 and 6 are detailed views of one of the fuel discharge outlets-shown in F ig-- ures 2 and 4; Figure 5' being avhorizontal sectional view taken on the lines'5.5 of Figs. 4: and 6 and Figure 6 being-an enlarged view in side elevation of the outlet,

shown partly in section. p

In the following description and in the claims, parts will be identified by specific charged in regulated amounts to a screwfeederll driven from a variable speed motor indicated symbolically by the driven belt 12 ands'o timed as'to 'vea regulated feed of the more or less soli fuel stream er unit of time to the feed pipe 13 from which it is discharged into the combined fuel distributor and agitator 14.

The furnace supplied by the distributor is indicated at 15 and is of the conventional form, provided with a plurality of injector twyers 16 equally spaced in a horizontal" plane about the furnace as is usual insome "types of such structures. The furnaceis sup-. plied through the'twyers with air fromra suitable source of relatively low pressure air indicated symbolically by the air line 16' andat the air line there; is shown sym bolically a source of high pressureair.

Referring particularlyto Figure for a detailed description of the distributor 14 it is noted that there isdisclosed' a cylindricalshell member 18 having a flanged bottom, 19 which can be readily removed from the shell to permit access to the in terior' of thedistributor The shell is; pro

vided'With a horizontally disposed partition 20 which divides the" interior into a lower a'ir pressure chamber 21 and an upper, mixing chamber 22. This'partition is provided across its entire surface with equally'spaced and relatively small. holes 23 designed to cause the air passing therethrough from the air chamber 21 to be evenly distributed throughout the lower portion of the mixing chamber. Air under relatively low pressure is introduced centrally through the bottom 19 by means of, a low pressure pipe 24 which leads from some suitable source of low pressure air supply, such as the blast furnace air main 25. A coneshaped' spreader 26 is disposed in themixing chamber; is spaced above the partition and'is concentrically positioned below the discharge end 27 of the feed pipe 13. The sides of the cone-spreader are inclined be yond the critical angle of the fuel fallingthereon and in the case of pulverized coal this angle is made over sixty degrees declination. The cone is provided with a discharging periphery 28 spaced from the inner side ofthe shell 18 so as to provide an annular passageway 29 for the fuel as it falls off the spreader towards the partition 20 in the form of a thin hollow cylinder." The cone spreader is supported centrally in the shell by means of angle brackets 30." a V The top ofthe mixing chamber is closed by means of a semi-porous cover 31 which forms an air bleeding inlet permitting some leakage of atmospheric airfrom the outside into the mixing chamber to agitate the fallingv fuel therein while permitting the formation of a partial vacuum in the upper portion of the mixing chamber as hereinafter described. In the device illustrated the cover is made of a heavy grade of canvas which has beenfound to be acceptable under the pressure conditions present in the device herein disclosed.

A plurality of discharge conduits 31 lead from the lower port-ion of the. mixing ch'ambe'r to the furnace, one conduit for each of the twyers 16. The intake ends of these conduits extend through the bottom 19, project above the'partition 20, are equally spaced apart in a circle concentric with the axis of the shell and are disposed within the down wardly projected outline of the discharge periphery 28 of the cone spreader. In the arrangement illustrated the intake ends are eight in number and equally spaced in a circle,the radius of which is half the radius of theshell. The uniform spacing of themtake ends of the conduits insures'at'all times an equal withdrawal of the diffused fuel from all partsof the inner periphery of the shell of fuel falling through the annular passageway 29. v

- For the purposeof insuring against the possibility of the fuel flooding into any one conduit and to assist in maintaining the fuel in its diffused condition the intake end of each of the conduits is provided "with'a'plurality of apertures 32 spaced about the side of a sleeve 33threadedinto the upper end of each of the conduits. The upper end of each of the sleeves is closed by a plug 34 which permits ready access'to sleeves in case the apertures 32 should become clogged.

The discharge end of each of the conduits 81 is connected to the outer end of. its corresponding twyer as shown in Figure 1, so

that the air pressure in line 17 acts to create,

a relatively high suction effect through the conduits 31. This high pressure tends to draw the carbonized fuel from the distributor to the twyers and acts through the twyers to project the fuel forcefully into the fur nace. It will be understood that the air pressures opened to themixing chamber are such that the suction effect through the conduits 31 will maintaina partial vacuum in the mixing chamber and that the pressure from the low pressure pipe 24 issufficient to maintain the falling fuel in the state of suspension but is not sufficient in volume to overcome the vacuum created in the mixing x chamber. It will be understood of course that the pressure and volume of the several pneumatic pressureshereinbefore described, will be regulated by the operator to fitthe peculiar condition present and for such purposessuitable control valves are provided.

In operation and assuming that a re ulated amount of the powdered coal, for in stance, is fed by the screw feeder 11 through the feed pipe 13 and that the several air supplies are in active operation, the desired form of carbonized fuel is fed uniformly into the furnace from all sides thereof.

As the fuelfalls on the cone spreader it slides down the same, moving in a substantially uniform stream off the discharge'edge of the spreader. As the fuel attempts to fall towards the perforated partition or! diaphragm 20, it is met by the upcoming air which causes the particles of the falling stream to separate'in the form of a cloud with the particles held suspended in the mixing chamber. The carbonaceous material remains in the mixing chamber'a ,sufiicient length of time toinsure the maximum pos sible separation of the particles and the thorough mixing of the air into andbetween the separated particles These 5 particles floating in the air medium will tend to obey the laws of gas diffusion and-will flow in under the spreader from which po'sition' theyare picked up by the circle of fuel discharging intake ports and conveyed by a multiplicity of conduits'to'the different portions'ofthe furnace. a

By means of a deviceof the character outlined it is possible to form a character of carbonized fuel in which a regulated amount of the solid particles are evenly distributed througha body of air and is which the density of the formed fuel is under the accurate control of the operator. This carbonized fuel. with its desired density, is fed to the furnace twyers and as there is an accurate "control of the air supplied through the twyers there necessarily results that there will be introduced into the furnace a regulated amount of fuel the thermal value of which is accurately controlled.

Having thus described my invention, I claim:

1. In the art of preparing a fuel charge to be fed to a blast furnace, the method which consists in introducing a substantially solid stream of the pulverized fuel into a space having av pressure condition therein less than atmospheric pressure, causing said streamxto spread out intoa thin layer and while so spread out to fall freely in said space, subjecting the thin falling stream to the action of air under relatively low pressure directed upwardly to hold the scattered fuel in suspension and withdrawing the suspended mixture of air and fuel thus formed from a plurality of points by suction under relatively high pressure.

2. In the art of preparing a fuel charge to be 'fedto a blast furnace, the methodwhich consists in introducing a stream of 3. In the-art of preparing a fuel-charge to be fedto'a blast. furnace, the method which consists in introducing a stream of the pulverized, fuel into a space havinga pressure condition therein les's than atmos-,

'pheric pressure, causing said stream to spread out while-falling freely in said-space,

subjecting the falling stream'to the action; of air under relatively low pressure-directed upwardly to holdthe scattered fuel in suspension and' withdrawing the suspended mixture of air and fuel thus formed by suction applied to the space at a: plurality I of equally spaced apart points thereby toefi'ect'an even Withdrawal. of the mixture ency of the mixturetobecomecondensed.

4. In the art'of mixing pulverized substance with air, the method whichr'consists in causing the substance to fall freely in the form of a thin hollow cylinder into a mixing space havinga relatively low pres sure condition therein,subjectingthe falling substance to the upwardly directed action of air on opposite sides of the cylinder under a-pressure sufficient to break-{up the cylinder into fine particles and-to keep the fine particles in suspension and withdrawing the diffused mixture of air and substance thus formed by a' suction effort under a: pressure greater than the pressure o-f-the air admitted to the space.

5. In the'art of mixing a pulverized substance with air, the method which consists in causingthe substanceto fall freely in a thin streaminto a mixing space having a relatively low-pressure condition therein, subjecting the v falling stream to the up wardly directedac'tion ofair under a pressure sufiicient to break up the stream into fine particlesand to keep the particles in suspension andwithdrawin'g thediffused mixture of air and substance thus formed-by a suction effort under a pressure" greater than the pressure of the air-admitted tothe space,'the suction action being divided and distributed in the space to minimize the fromfthe space and torminimize any tend- 1 relatively low pressure tov air chamber,

I so

flooding of the mixture into any one outlet and to prevent the condensing of the mixturep 6. A combined agitator vand distributor provided with aperforated partition forming an upper; mixing chamber and a lower air chamber, means for supplying air under relatively low pressure to air chamber,

means for supplying a pulverized substance means for supplying a pulverized substance to said mixing, chamber to meet the low pres sure air, directed upwardly through" said I. perforated partition, means within the mixing chamber for spreadingthel substance introduced thereby to direct it evenly over the entire area" of the. upwardly-"mov ngair, a suction outlet from saidmixing chamber to withdraw themixtui e. of air and substance" from -:the;,mixing -:chamber,,.said' mixing;

chamberbeing closed. except for an'atmospheric ,airbleeding inlet' of less intaking capacity than said suction efiectpresent whereby a partial vacuum is maintained in said mixing chamber.

- SLA. combined Iagitator and distributor 1 provided with a perforated partition form ing an upper mixin 'cha-mber anda lower.

air chamber, vmeans for supplyingair under relatively low, pressure to air chamber, means for supplying a pulverized substance to said mixing chamber to meet the low pressure air directed upwardly through said perforated partition, a suction outlet from said mixing chamber to withdraw the mixture. of air and substance from the mixing chamber, said mixing chamber bein closed.

except for'an atmosphericair blee ing inlet of' less intaking capacity than said suction effectpresent whereby a partial vacuum is maintained in said mixing chamber, said suction outlet provided with means tending, toobstruct the free discharge of the mixture from said mixing chamber.

9. In a device of the class described, a

cylindrical member having a closed bottom.

and an open top, a perforated partition for separating the interior of themember into an upper mixing-chamber anda lower air chamber, a semi porous cover for closing the open top while permitting a slight air leakage, means for introducing fuel through said cover and into said mixing chamber, means disposed in said mixing chamber below said introducing means for spreading the fuel as it falls towards said perforated partition, means for introducing air under pressure to said air chamber in a volume sufficient to suspend said falling fuel in said mixin chamber.

10. n a. device of the class described, a cylindrical member having a closed bottom and an open top, a perforated partition for separating the interior of the member into an upper mixing chamber and a lower air chamber, a semi-porous cover for closing the open top while permitting a slight air leakage, means for introducing fuel through said cover and into saidmixing chamber, means disposedvin said mixing chamber below. said introducing means for spreading the fuel as it falls towardssaid'perforated partition, means for introducing air under pressure to said air chamber in 'ayolume' s-ufiicient. to suspend said falling. fuel in said mixing chamber and an outlet. for the mixture of airiand suspended fuel disposed beneath said spreadingmeans.

11. In a device'ofthe class and an opentop, a perforated partition Y described,; a. cylindncal me'mber having aclosedlbottom for separatingthe interior of the Inember into an upper mixing chamber and'a lowerf air chamber, a semi-porous cover for closing the open top "while'lpermittinga'slight' air leakage," *means for introducing: .fuel through said cover and into-said mixing chamber, a conical spreader having a fuel dischargingperiphery and a plurality 'of outlets for the mixture of air and suspended fuel; said outlets being disposed in acircle below and within the projected outline of tne periphery of said spreader and a receptacle for receiving the dischargefr'om all of said outlets. V I i 12. In a device of the class described, a cylindrical member having a closed bottom and an open top, a perforated partition for separating the interior of the memberinto an upper mixing chamber and a lower air chamber, asemi-porous cover for closing the open top while permitting a slight air leakage, means for introducing fuel through said cover and into said mixing chamber, a conical spreader having a fuel discharging periphery and a plurality of outletsfor the mixture of air and suspended fuel, said outlet-s being disposed in a circle below and within the projected outline of the periphery ofvsaid spreader and a receptacle for receiving the discharge from all of said outlets, each of'said outlets provided with a plurality of intakes to assist in maintaining the fuel diffused in themixture.

13. In adevice of the class described,the

combination with a furnace, of means for feeding 'a mixture of pulverized fuel and air to said furnace, said means including a source of fuel supply means for feeding a fuel stream in a regulated amount per unit of time from said source, a combined agitator and distributor for receiving and scattering the fuel streams, means for diffusing air uniformly through said scattered fuel and for holding the same in suspension, a plurality of conduits having their intake ends spaced apart in said combined agitator and distributor so as to draw from all parts of the diffused fuel thereon and having their discharge ends spaced apart in said furnace and pneumatically actuated means for causing the mixture of air and diffused fuel to pass through said conduits and into said furnace.

14. In a device of the class described, the combination with a furnace, of means for feeding a mixture of pulverized fuel and air to said furnace, said means including a combined agitator and distributor for receiving and scattering the fuel stream, means for diffusing air under pressure through said scattered fuel and for holding the same in suspension, a plurality of conduits having their intake ends spaced apart in said combined agitator and distributor and having their discharge ends spaced apart and opening into said furnace at a plurality of points whereby the mixture of air and diffused fuel will be introduced thereto. in a plurality of directions and pneumatically actuated means for causing the mixture of air and fuel to'pass through said conduits and into said furnace.

15. In a device of the class described, the

' combination of a mixing chamber, means for introducing fuel so as to fall into said chamber, means for spreading the fuel as it falls towards the bottom of the chamber, means for directing air to move in an even distribution upwardly through said bottom to meet the falling fuel and to hold the same in suspension diffused in the air and pneumatically actuated means for discharging the mixture of air and suspended fuel from said chamber.

16. In a device of the class described, the combination of a mixing chamber, means for introducing fuel so as to fall into said chamber, means for spreading the fuel as it,

falls towards the bottom of the chamber, means for directing air to move in an even distribution upwardly through said bottom to meet the falling fuel and to hold the same in. suspension difi'usedin the air, means permitting a slight air leakage to said mixing chamber to permit a partial vacuum to form therein, suction means open to said chamber to maintain said partial vacuum therein and to discharge the mixture of air and suspended fuel from said-chamber.

17. In a device of the class described, a mixing chamber havingmeans defining the bottom thereof for diffusing air passed therethrough, means for causing pulverized fuel to fall freely through said chamber, means for passing air under pressure through said air diffusing bottomto act on the fuel and suspend the same diffused in the air present in the chamber, a semiporous cover for said chamber permitting an air leakage thereto, said chamber provided with a diffused fuel discharge port and pneumatic means acting through said port to withdraw thefuel from the chamber under a relatively low pressure condition.

18. In a device of the classdescribed, the combination with a furnace having a plurality of fuel intakes, injector twyers at each of said intakes, of means for supplying said twyers equally and a mixture of air with pulverized fuel diffused evenly throughout the air, said means including a fuel distributor, means for feeding fuel to the distributor, means for causing air under relatively low pressure to be projected evenly throughout the entire mass of the fuel and to hold the same in suspension in diffused condition,conduits leading from spaced apart points in said distributor to said twyers r thereby to draw from all parts of the same, and a source of relatively high pressure air supplied to said twyers to drawv the fuel mixture from the distributor and to project the same through the twyers and into the furnace.

19. In a device of the class described, the combination with a furnace, an injector twyer for introducing fuel under pressure to the furnace, of means for supplying said twyer with a mixture of air having a pulverized fuel diffused therein, said means including a distributor having elements therein for subjecting a falling, thin stream of the pulverized fuel to the action of a current of air under relatively low pressure and a source of air under relatively high pressure directed through said twyers for projecting the fuel into the furnace and for drawing the diffused fuel from the distributor and int the twyer.

Signed at Garfield in the county of Salt Lake and Stateof Utahthis 17th day of Nov. A. D. 1919. RICHARD A. WAGSTAFF.

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