R, A, WAGSTAFF, APPARATUS AND METHOD OF DISTRIBUTING PULVERIZED COAL IN BLAST FURNACE WORK.

Transcription

1 R, A, WAGSTAFF, APPARATUS AND METHOD OF DISTRIBUTING PULVERIZED COAL IN BLAST FURNACE WORK. APPLICATION FED DEC, 4, 1919, 1,411, Patented Mar, 28, SHEETS-SHEET 1. w/oaaaa ae ALMARIZED CoA ALAs Alaeace A3 WAN s Til. V/ Aov ApaaSSARE afe HAVE fe / \a screw. E. AAEA? zaz =:::::::22:3 a. 12- k1?tis - st DisTRIBuroe AARESSuee ARIAE A/OOA. A. f/vaf 68)itv.css co: (Be4ald C t a-e-org 334 his &lttoric 22s21-2 "EOy 2. to

2 R, A, WAGSTAFF, APPARATUS AND METHOD OF DISTRIBUTING PULVERIZED COAL IN BLAST FURNACE WORK. APPLICATION FILED DEC, 4, 1919, 1,411,072. Patented Mar 28, SEES-SHEET 2. A. as a xxx ar. act 68), twossos: a0 is O 2A.ZOW. Ziv. 2 sy1 83 B: &listic,

3 O UNITED STATES PATENT OFFICE. RICHARDA, WAGSTAFF, of SALT LAKE CITY, UTAH, AssIGNor. To AMERICAN SMELTING AND REFINING COMPANY, OF NEW YORK, N.Y., A CORPORATION OF NEWJERSEY. APPARATUS AND METHOD OF DISTRIBUTING PULVERIZED coal IN BLAST-FURNAc WORK 1411,072. Specification of Letters Patent. Patented Mar. 28, Application filed December 4, 1919; serial No. 342,393. To all chon, it may concern; - carbonaceous material which can be ejected Be it known that I, RICHARD A. WAG in this form into the furnace by high pres STAFF, a citizen of the United States, and Sure air. resident of Salt Lake City, in the county of Referring to the mechanical features of Salt Lake and State of Utah, have invented the disclosure, one of the objects of this phase certain new and useful Improvements in Ap of the invention is to provide a simple and paratus and Methods of Distributing Pul economically actuated device for forming verized Coal in Blast-Furnace Work, of the peculiar character of fuel hereinbefore: which the following is a specification. Outlined, and for maintaining the fuel in The invention relates to an improved its diffused condition until it is discharged method for preparing a carbonaceous fuel into the combustion zone of the furnace. and for feeding the same to a blast or other s Another object of the invention featuring metallurgical furnace; and the invention simplicity of construction and economy in further relates to an improved instrumen Operation is to provide such a device as can tality for practicing the method... be used as an attachment to conventional It has been appreciated, heretofore that blast furnace plants and which can utilize in certain metallurgical operations it is de the sources of air pressures present in con ventional plants of this character. condition into a blast furnace, for instance, Various other objects and advantages of by pulverizing solid fuel and feeding the pulverized fuel to the injector twyers by the invention will be in part obvious from an inspection of the accompanying draw means of which the more or less diffused fuel ings and in part will be more fully set forth. was scattered into the interior of the fur in the following particular description of. nace. The air pressure on the twyers, how One form of mechanism embodying my in ever, is usually quite high, due to the neces Vention, and the invention also consists in sity of supplying sufficient oxygen to Sup i. sirable to introduce fuel in a semi-gaseous dry port the combustion present. This high pressure air, acting for the necessarily short limits of time on the solid fuel stream fed to the twyers, could not effectively scatter or diffuse the pulverized fuel. As the result of the more or less concentrated condition of the fuel introduced into the furnace in trior, the resulting act of combustion was a relatively slow burning rather than the ideal explosive act which is preferable in cer tain metallurgical operations. Accordingly, one of the primary objects 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 here tofore been fed to the twyers. The present invention contemplates the economic forma tion of the carbonized fuel which is further characterized by extreme minuteness of the particles of the solid fuel and in which the particles are uniformly scattered in the air present. In other words, the invention fea tures the formation of a nebulous cloud of certain new and novel features of construc tion and combination of parts hereinafter set forth and claimed. - Referring to the accompanying drawings: Figure 1 is a diagrammatic representa tion in elevation of a plant organized to practice the method herein disclosed, but it is to be understood that the elements illus trated are merely suggestive of one perfect edimeans for practicing the method; Figures 2 to 4, inclusive, are enlarged de tailed views of the coal distributor shown in Figure 1: Figure 2 being a horizontal sec tional view taken on the lines 2-2 of Fig ures 1 and 4; Figure 3 being a plan view looking down upon the coal distributor with its cover removed; and Figure 4 being a ver tical Sectional view taken axially through the distributor and on the line 4-4 of Fig ure 3; Figures 5 and 6 are detailed views of one of the fuel discharge outlets shown in Fig ures 2 and 4; Figure 5 being a horizontal Sectional view taken on the lines. 5-5 of Figs, 4 and 6 and Figure 6 being, an en larged view in side elevation of the outlet shown partly in section. In the following description and in the OO 05

4 2 1,411,072 claims, parts will be identified by specific. spreader is supported centrally in the shell names for convenience of expression but they by means of angle brackets 30. are intended to be as generic in their applica The top of the mixing chamber is closed tion to similar parts as the art will permit. by means of a semi-porous cover 31 which Referring to Figure 1 for a general view forms an air bleeding inlet permitting some of the plant organization, there is shown a leakage of atmospheric air from the outside hopper 10 constituting a source of supply into the mixing chamber to agitate the fall for the pulverized carbonaceous material ing fuel therein while permitting the forma which, in one physical embodiment of the in tion of a partial vacuum in the upper por 10 vention, is powdered coal. The fuel is dis tion of the mixing chamber as hereinafter 75 - charged in regulated amounts to a screw. described. In the device illustrated the cover feeder 11 driven from a variable speed mo is made of a heavy grade of canvas which tor indicated symbolically by the driven belt has been found to be acceptable under the 12 and so timed as to SE a regulated feed pressure conditions present in the device 15 of the more or less solid fuel stream per unit herein disclosed.. 80 of time to the feed pipe 13 from which it is A plurality of discharge conduits 31 lead discharged into the combined fuel distribu from the lower portion of the mixing cham tor and agitator 14. ber to the furnace, one conduit for each of The furnace supplied by the distributor is the twyers 16. The intake ends of these con 20 indicated at 15 and is of the conventional duits extend through the bottom 19, project 85 form, provided with a plurality of injector above the partition 20, are equally spaced twyers 16 equally spaced in a horizontal apart in a circle concentric with the axis of plane about the furnace as is usual in some the shell and are disposed within the down types of such structures. The furnace is sup Wardly projected outline of the discharge pe 25 plied through the twyers with air from a riphery 28 of the cone spreader. In the ar 90 suitable source of relatively low pressure air rangement illustrated the intake ends are indicated symbolically by the air line 16' eight in number and equally spaced in a and at the air line 17 there is shown sym circle, the radius of which is half the radius bolically a source of high pressure air. of the shell. The uniform spacing of the in 30 Referring particularly to Figure 4 for take ends of the conduits insures at all times 95 a detailed description of the distributor an equal withdrawal of the diffused fuel 14 it is noted that there is disclosed a cy from all parts of the inner periphery of the - lindrical-shell member 18 having a flanged shell of fuel falling through the annular pas bottom 19 which can be readily removed sageway from the shell to permit access to the in. For the purpose of insuring against the 100 terior of the distributor. The shell is pro possibility of the fuel flooding into any one vided with a horizontally disposed par conduit and to assist in maintaining the fuel tition 20 which divides the interior into in its diffused condition, the intake end of a lower, air-pressure chamber 21 and an each of the conduits is provided with a plu 40 upper, mixing chamber 22. This partition rality of apertures 32 spaced about the side is provided across its entire surface with of a sleeve 33 threaded into the upper end of 05 equally spaced and relatively small holes 23 each of the conduits. The upper end of each design ed to - cause the air passing there of the sleeves is closed by a plug 34 which through from the air chamber 21 to be permits ready access to sleeves in case the evenly distributed throughout the lower por apertures 32 should become clogged. O tion of the mixing chamber. Air under rela The discharge end of each of the conduits tively low pressure is introduced centrally 31' is connected to the outer end of its cor through the bottom 19 by means of a low responding twyer, as shown in Figure 1, so pressure pipe 24 which leads from some suit that the air pressure in line 17 acts to create able source of low pressure air supply, such a relatively high suction effect through the 5 as the blast furnace air main 25. A cone conduits 31. This high pressure tends to shaped spreader 26 is disposed in the mix draw the carbonized fuel from the distribu ing chamber; is spaced above the partition tor to the twyers and acts through the twy and is concentrically positioned below the ers to project the fuel forcefully into the fur discharge end 27 of the feed pipe 13. The nace. It will be understood that the air 120 sides of the cone-spreader are inclined be pressures opened to the mixing chamber are yond the critical angle of the fuel falling such that the suction effect through the con thereon and in the case of pulverized coal duits 31 will maintain a partial vacuum in this angle is made over sixty degrees declina the mixing chamber and that the pressure 60 tion. The cone is provided with a discharg from the low pressure pipe 24 is sufficient to 125 ing periphery 28 spaced from the inner side maintain the falling fuel in the state of sus of the shell 18 so as to provide an annular pension but is not sufficient in volume to passageway 29 for the fuel as it falls off the overcome the vacuum created in the mixing spreader towards the partition 20 in the chamber. It will be understood of course 65 form of a thin hollow cylinder. The cone that the pressure and volume of the several 130

5 ,072 pneumatic pressures hereinbefore described, 2. In the art of preparing a fuel charge 65 will be regulated by the operator to fit the to be fed to a blast furnace, the method. peculiar condition present and for such pur. which consists in introducing a stream of poses suitable control valves are provided. the pulverized fuel into a space, causing In operation and assuming, that a regu said stream to spread out while falling lated amount of the powdered coal, for in freely in said space, subjecting the falling stance, is fed by the screw feeder 11 through stream while in suspension to the action of the feed pipe 13 and that the several air upwardly directed air under a pressure suf supplies are in active operation, the desired ficient to keep the fuel in suspension but form of carbonized fuel is fed uniformly not enough in volume to overcome the re into the furnace from all sides thereof. duced pressure condition, said air being As the fuel falls on the cone spreader it directed upwardly to hold the scattered fuel slides down the same, moving in a substan in suspension and withdrawing the suspend tially uniform stream of the discharge edge ed mixture of air and fuel thus formed by of the spreader. As the fuel attempts to suction under relatively high pressure and fall towards the perforated partition or ejecting the withdrawn mixture under pres S0 diaphragm 20, it is met by the up-coming sure into the blast furnace. air which causes the particles of the falling: 3. In the art of preparing a fuel charge stream to separate in the form of a cloud to be fed to a blast furnace, the method with the particles held suspended in the mix which consists in introducing a stream of ing chamber. The carbonaceous material the pulverized fuel into a space having a s s remains in the mixing chamber a sufficient pressure condition therein less than atmos length of time to insure the maximum pos pheric pressure, causing said stream to sible separation of the particles and the spread out while-falling freely in said space, thorough mixing of the air into and between subjecting the falling stream to the action. the separated particles. These particles of air under relatively low pressure directed 90 floating in the air medium will tend to obey upwardly to hold the scattered fuel in sus. the laws of gas diffusion and will flow in pension and withdrawing the suspended under the spreader from which position mixture of air and fuel thus formed by. they are picked up by the circle of fuel Suction applied to the space at a plurality discharging intake ports and conveyed by of equally spaced apart points thereby to 95 a multiplicity of conduits to the different effect an even withdrawal of the mixture. portions of the furnace. from the space and to minimize any tend By means of a device of the character ency of the mixture to become condensed. outlined it is possible to form a character of 4. In the art of mixing a pulverized sub carbonized fuel in which a regulated amount stance with air, the method which consists 100 of the solid particles are evenly distributed in causing the substance to fall freely in through a body of air and is which the the density of the formed fuel is under the mixing form space of a having thin hollow a relatively cylinder low into pres a accurate control of the operator. This car sure condition therein, subjecting the falling bonized fuel with its desired density, is substance to the upwardly directed action 05 fed to the furnace twyers and as there is of air on opposite sides of the cylinder an accurate control of the air supplied under a pressure sufficient to break up the through the twyers there necessarily re cylinder into fine particles and to keep the Sults that there will be introduced into the fine particles in suspension and withdrawing furnace a regulated amount of fuel the ther the diffused mixture of air and substance l, 10 mal value of which is accurately controlled. thus formed by a suction effort under a: Having thus described my invention, I pressure greater than the pressure of the air claim: - admitted to the space. 1. In the art of preparing a fuel charge to 5. In the art of mixing a pulverized sub be fed to a blast furnace, the method which stance, with air, the method which consists 15 consists in introducing a substantially solid in causing the substance to fall freely in stream of the pulverized fuel into a space thin stream into a mixing space having a having a pressure condition therein less relatively low, pressure condition therein, than atmospheric pressure, causing said subjecting the falling stream to the up stream to spread out into a thin layer and wardly directed action of air under a pres 20 while so spread out to fall freely in said sure sufficient to break up the stream into Space, subjecting the thin falling stream to fine particles. and to keep the particles in the action of air under relatively low pres suspension and withdrawing the diffused sure directed upwardly to hold the scattered mixture of air and substance thus formed by fuel in suspension and withdrawing the a suction effort under, a pressure greater suspended mixture of air and fuel thus than the pressure of the air admitted to the 125 formed from a plurality of points by suc space, the suction action being divided and tion under relatively high pressure. distributed in the space to minimize the

6 ,072. flooding of the mixture into any one outlet age, means for introducing fuel through said and to prevent the condensing of the mix cover and into said mixing chamber, means ture..... disposed in said mixing chamber below said 6. A combined agitator and distributor introducing means for spreading the fuel provided with a perforated partition form as it falls towards said perforated parti ing an upper mixing chamber and a lower tion, means for introducing air under pres air chamber, means for supplying air under sure to said air chamber in a volume suf relatively low pressure to air chamber, ficient to suspend said falling fuel in said means for supplying a pulverized substance mixing chamber. 0. to said mixing chamber to meet the low 10. In a device of the class described, a pressure air directed upwardly through said cylindrical member having a closed bottom perforated partition, a suction outlet from and an open top, a perforated partition for said mixing chamber to withdraw the mix separating the interior of the member into ture of air and substance from the mixing an upper mixing chamber and a lower air chamber, said mixing chamber being closed chamber, a semi-porous cover for closing 80. except for an atmospheric air bleeding in the open top while permitting a slight air let of less intaking capacity than said suc leakage, means for introducing fuel through tion effect present whereby a partial vacuum said cover and into said mixing chamber, is maintained in said mixing chamber. means disposed in said mixing chamber be A combined agitator and distributor low, said introducing means for spreading 85 provided with a perforated partition form the fuel as it falls towards said perforated ing an upper mixing chamber and a lower partition, means for introducing air under air chamber, means for supplying air under pressure to said air chamber in a volume. relatively low pressure to air chamber, sufficient to suspend said falling fuel in 25 means for supplying a pulverized substance said mixing chamber and an outlet for the 90 to said mixing chamber to meet the low press mixture of air and suspended fuel disposed sure air directed upwardly through said beneath said spreading means perforated partition, means within the mix 11. In a device of the class described, a ing chamber for spreading the substance in cylindrical member having a closed bottom troduced thereby to direct it evenly over the and an open top, a perforated partition entire area of the upwardly moving air, a for separating the interior of the member suction outlet from said mixing chamber to into an upper mixing chamber and a lower withdraw the mixture of air and substance air chamber, a semi-porous cover for clos from the mixing chamber, said mixing. ing the open top while permitting a slight 35 chamber being closed except for an atmos air leakage, means for introducing fuel pheric air bleeding inlet of less intaking through said cover and into said mixing capacity than said suction effect present chamber, a conical spreader having a fuel whereby a partial vacuum is maintained in discharging periphery and a plurality of said mixing chamber outlets for the mixture of air and suspended A combined agitator and distributor fuel, said outlets being disposed in a circle 05 provided with a perforated partition form below and within the projected outline of ing an upper mixing chamber and a lower. the periphery of said spreader and a re air chamber, means for supplying air under ceptacle for receiving the discharge from relatively low pressure to air chamber, ai of said outlets. 45 means for supplying a pulverized substance 12. In a device of the class described, a l0. to said mixing chamber to meet the low pres cylindrical member having a closed bottom sure air directed upwardly through said and an open top, a perforated partition for perforated partition, a suction outlet from Separating the interior of the member into said mixing chamber to withdraw the mix an upper mixing chamber and a lower air 50 ture of air and substance from the mixing chamber, a semi-porous cover for closing the 15 chamber, said mixing chamber being closed open top while permitting a slight air leak except for an atmospheric air bleeding in age, means for introducing fuel through let of less intaking capacity than said suc said cover and into said mixing chamber, tion effect present, whereby a partial vacuum a conical spreader having a fuel discharg 55 is maintained in said mixing chamber, said ing periphery and a plurality of outlets for 20 suction outlet provided with means tend the mixture of air and suspended fuel, said ing to obstruct the free discharge. of the outlets being disposed in a circle below and mixture from said mixing chamber. Within the projected outline of the periph 9. In a device of the class described, a ery of Said spreader and a receptacle for 60 cylindrical member having a closed bottom. receiving the discharge from all of said out 125 and an open top, a perforated partition for lets, each of said outlets provided with a separating the interior of the member into plurality of intakes to assist in maintaining an upper mixing chamber, and a lower air the fuel diffused in the mixture. chamber, a semi-porous cover for closing the 13. In a device of the class described, the 65 open top while permitting a slight air leak combination with a furnace, of means for 130

7 ,411,072 feeding a mixture of pulverized fuel and chamber to permit a partial vacuum to form air to said furnace, said means including therein, suction means open to said chamber source of fuel supply means for feeding a to maintain said partial vacuum therein and fuel stream in a regulated amount per unit to discharge the mixture of air and sus of time from said source, a combined agi pended fuel from said chamber. tator and distributor for receiving and scat 17. In a device of the class described, a tering the fuel streams, means for diffusing mixing chamber having means defining the air uniformly through said scattered fuel bottom thereof for diffusing air passed and for holding the same in suspension, a therethrough, means for causing pulverized plurality of conduits having their intake fuel to fall freely through said chamber, ends spaced apart in said combined agi means for passing air under pressure tator and distributor so as to draw from through said air diffusing bottom to act on all parts of the diffused fuel thereon and having their discharge ends spaced apart the fuel and suspend the same diffused in the air present in the chamber, a semi in said furnace and pneumatically actuated porous cover for said chamber permitting an means for causing the mixture of air and air leakage thereto, said chamber provided diffused fuel to pass through said conduits with a diffused fuel discharge port and and into said furnace. pneumatic means acting through said port 14. In a device of the class described, the to withdraw the fuel from the chamber un combination with a furnace, of means for der a relatively low pressure condition. feeding a mixture of pulverized fuel and 18. In a device of the class described, the air to said furnace, said means including a combination with a furnace having a plu combined agitator and distributor for receiv rality of fuel intakes, injector twyers at each ing and scattering the fuel stream, means for diffusing air under pressure through of said intakes, of means for supplying said twyers equally and a mixture of air with said scattered fuel and for holding the same pulverized fuel diffused evenly throughout in suspension, a plurality of conduits hav ing their intake ends spaced apart in said the air, said means including a fuel distrib utor, means for feeding fuel to the dis combined agitator and distributor and hav ing their discharge ends spaced apart and tributor, means for causing air under rel atively low pressure to be projected evenly opening into said furnace at a plurality of points whereby the mixture of air and dif throughout the entire mass of the fuel and to hold the same in suspension in diffused fused fuel will be introduced thereto in condition, conduits leading from spaced apart a plurality of directions and pneumatically points in said distributor to said twyers actuated means for causing the mixture of thereby to draw from all parts of the same, air and fuel to pass through said conduits and a source of relatively high pressure air and into said furnace. supplied to said twyers to draw... the fuel 15. In a device of the class described, th mixture from the distributor and to project combination of a mixing chamber, means for the same through the twyers and into the introducing fuel, so as to fall into said furnace. chamber, means for spreading the fuel as it 19. In a device of the class described, the falls towards the bottom of the chamber, combination with a furnace, an injector means for directing air to move in an even distribution upwardly through said bottom twyer for introducing fuel under pressure to the furnace, of means for supplying said to meet the falling fuel and to hold the twyer with a mixture of air having a pull. Same in suspension diffused in the air and pneumatically actuated means for discharg verized fuel diffused therein, said means in cluding a distributor having elements there ling the mixture of air and suspended fuel in for subjecting a falling, thin stream of from said chamber. the pulverized fuel to the action of a current 16. In a device of the class described, the of air under relatively low pressure and a combination of a mixing chamber, means source of air under relatively high pressure for introducing fuel so as to fall into said directed through said twyers for projecting chamber, means for spreading the fuel as it. the fuel into the furnace and for drawing the falls towards the bottom of the chamber, diffused fuel from the distributor and int means for directing air to move in an even the twyer. distribution upwardly through said bottom Signed at Garfield in the county of Salt to meet the falling fuel and to hold the same in suspension diffused in the air, means per Lake and State of Utah this 17th day of Nov. A. D mitting a slight air leakage to said mixing RICHARD A. WAGSTAFE