US2124437A - Blast furnace and tuyere structure and method of operation - Google Patents

Description

July 19,1938. K, STEINBA CHER BLAST FURNACE AND TUYERE STRUCTURE AND METHODOF OPERATION Filed Jan. 10', 195s 2 Sheets-Sheet 1 INVENTOR y 3 K, STEINBACI-IER 7 2,124,437

BLAST FURNACEAND TUYERE STRUCTURE AND METHOD OF CPERATION Fil ed Jan. 10, 1956 2 Sheets- Sheet 2 INVENTOR Patented July 19, 1938 PATENT OFFICE.

' BLAST FURNACE AND ME AND TUYERE STRUCTURE rnop OF OPERATION Karl Steinbacher, Portsmouth, Ohio x App lication January 10, 1936, Serial No. 58,517

d. Claims.

This invention relates to blast furnace and tuyere structure and method of operation, and more particularly to the art of reducing ore in r a blast furnace and controlling the blast char- 5 acteristics whereby important new and useful results are obtained. A novel blast furnace structure and a novel method of operating a blast furnace are provided. Also a novel tuyere structure useful in accomplishing the desired re- 1 suits is provided.

The standard blast furnace comprises an up right furnace shaft into which ore, fuel and flux in proper proportions are introduced through a specially constructed opening in thetop. Heated 15 air isblown into the furnace near the bottom through devices known as tuyeres, the nitrogen of the air, together with the products of combustion and reduction, passing upwardly and escaping at the top of the furnace. Periodically 5- slag andmolten -metal are drawn oif through suitable openings provided below the tuyeres.

, In a standard blast furnace structure each tuyere is mounted in a holding devicedrnown as a tuyere cooler.

through which cooling water is adapted to be circulated. The tuyere is likewise of generally tapered or conical construction, being ordinarily made of copper and having a jacket portion through which cooling water is adapted to be circulated. The tuyere is introduced into the tuyere cooler and held thereby. The tuyere ordinarily projects inwardly of the furnace wall. The axes of the tuyere and cooler are perpendicular or normal to the face wall.

Ordinarily the number of tuyeres in a blast furnace varies between eight and sixteen. The tuyeres are arranged in evenly spaced relation in a single circumferential series in the same plane perpendicular to the awe of the furnace. Thus during operation of the furnace all of the tuyeres discharge or direct their blasts straight at the axis of the furnace. This results in build- ,ing up the static pressure inside the ace d notonly to the resistance offered to the blast by the steel: in the furnace but also to the interference of the various blasts or gas streams with one another. The exact path of each blast is naturally determined in a considerable measureby the resistance ofiered by the stock in the furnace. Consequently the resistance points shift during operation of the furnace, the result being that the desired uniform flow of air or gas is interfered with. This in turn results in non-uniform stock flow.

circumferential series Such cooler comprises essen- 2.1 tially a tapered or generally conical copper shell If the stock flow is not uniform the transfer of heat and the reduction of oxides is not as complete and uniform as it should be. resulting in impairment of the quality of the pig iron being produced. Thereduction tends to be carried out in more or less isolated portions of the stock, other portions being less fully reduced, with the result that the pig iron contains an undesirably highpercentage of impurities.

1 I provide for eliminating the tendency of the ,[P blasts to interfere with one another .and, on the contrary, I control the blasts so that they cooperate with one another to effect more complete and uniform reduction of the ore. I direct the blasts eccentrically of the furnace and so as to create a controlled swirling draft. The blasts are preferably all similarly directed so that the swirling draft will be unimpaired. It may be either clockwise or counter-clockwise, the sam result being obtained in either event.

I preferably introduce into the blast furnace a of blasts directed eccentrically of the iurnaceand substantially in a common plane perpendicular to the axis-of the furnace and thereby create a controlled swirling 25 inward and'upward draft. As the outlet for the gases is at the top ofthe furnace they will move upwardly, and by proper control of the blast angles I can emciently distribute the blast throughout a relatively great portion of the 30v stock, eliminating the'tendency toward building up of static pressureby reason of interference between the blasts andgreatly. increasing the eficiency of the process. The result is a superior product and also an increased yield from the 35 blast furnace per operating period.

I am aware that it has heretofore been prop:sed to direct tuyeres at an angle downwardly and laterally toward the hearth of a melting furmice to refine materialonsuch hearth, but this to is entirely different from my invention, and, in fact, directing the tuyres downwardly in a blast furnace would bring about undesirable conditionsin the furnace which would interfere with proper reduction of the stock and would also tend 45- to reduce the intensity of the draft by creating a force opposite to the direction of movement of the gases. I am also aware that it has heretofore been proposed to, direct the blast of a single tuyere or of, isolated tuyeres toward particular 50 spots in the stock column where an increased reduction efiect may be desired. This however, tends rather to interfere with proper carrying out of the operation than to increase its efliciency.

- rents in the blast through the tuyere.

portion of the bore is curved so I provide a novel forni of tuyere which is relatively simple in construction and inexpensive to manufacture and which is ideally suited for the accomplishment of my improved results. I preferably provide atuyere adapted .to'be applied to a standard blast furnace and to be held by the standard type of tuyere holder or cooler whose axis is substa'ntiallynormal to the furnace wall. Thus my improved results can be obtained without any modification whatever of a standard blast furnace except removal of placement thereof by my improved tuyeres.

In one of its present preferred forms the tuyre has an outer shape approximating the shape of a cone truncated at an acute angle to I it is disfrom the tuyre and the tuyre prefera longitudinally convex outer surface portion facing generally away from the direction of discharge of the blast.

My tuyre may have a generally conical base portion and a substantially flat nose surface extending at an acute angle to the axis of the base portion, the tuyere having a bore extending within the base portion and'intersecting the flat nose surface. In one preferred form of the tuyere any section through it normal to the axis of the bore is substantially symmetrical in all directions about its center. The outer shape of the tuyre may approximate the shape of a truncated cone with non-parallel bases and with a bore therethroughf Other details, objects and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof and certain present preferred methods of practicing the same proceeds.

certain present preferred embodiments of the invention and have diagrammatically illustrated certain present preferred methods of practicing the same, in which Figure l is a partial central vertical cross-sectional view through a blast furnace of standard construction but having my invention applied thereto; v

Figure 2- is acentral longitudinal cross-sectional view through one form of tuyere;

Figure 3 is a view of the tuyere showndn Figure 2 viewed from the left;

, Figures 4 and 5 tuyeret-and Figures 6, 7; 8 and 9 are diagrammaticviews illustrating the carrying out of my process.

Referring now more particularly to the drawcone and fits within an opening 4 provided therecooler has a passage 5 for in the wall 2. The

the tuyeres and reat rightv charge of the blast.

are views of modified forms of cally in Figure 6. In this figure thereinthrough which cooling water is adapted to be passed in well known manner. The axis of'the cooler is normal to the axis of the wall 2.

blast comprises preheated air and enters the tuyre through a nozzle 1 at high velocity. as well known in the art.

The tuyre 8 is shown as fitted within the cooler 5 in operative position and receiving preheated air through the nozzle 1 to produce a blast within the furnace.. Another similar tuyre spaced a short distance around the furnace wall is shown at 9. There may, for example, .be twelve such tuyeres uniformly spaced about the furnace wall and all disposed in the same relationship with respect thereto. with a passage l0 through which cooling water isadaptedto the art.

The tuyere 8 comprises a base portion I I formed externally in the shape of a right circular cone and having therein a tapered bore [2 (Figure 2) The tuyere'is, as above stated, adapted to be held by a standard tuyere cooler as now used in practically all modern blast furnaces. The outer be circulated, as well known in Each of the tuyeres is provided v shape of the tuyre is approximately the shape of a cone truncated at an acute angle to its axis as shown, although the outer surface at I 3 adjacent the nose of the tu'yre vexly curved opposite the is longitudinally coneneral direction of dis- As will be apparent; this external curvature of the tuyre as at l3 assists in minimizing the possible interference of the tuyre with the blast of the next tuyere of the series as 9, especially when the tuyere angle is relatively great (see Figures 4 and'l),

The bore of the tu-yre is curved as shown so that the direction of the blast is changed in the tuyere. The longitudinally concave. portion l5 of the bore is formed as a smooth gradual curve to minimize cross currents in the blast through the tuyre. The nose surface llof'the tuyere extends substantially at right angles to the direction of the blast as it'i's discharged from the tuyre. The tuyere is contained entirely-within the confines of a cone defined by its base portion II. In the accompanying drawingsI have shown Any section through the tuyere normal to the axis of the bore is substantially symmetrical in alldirections about its center. This is not exactly true but it is a close approximation. In

' fact, in its preferred form the outer shape of the tuyere approximatesthe shape of a truncated cone with non-parallel bases. r

The tuyeres preferably, although not necessarily, project inwardly past the wall of the furmace, and in the preferred form shown they project radially inwardly. However, on account of the peculiar formation of the tuyeres they discharge their blasts into the furnace eccentrically thereof and so as to create a swirling draft in the furnace as indicated diagrammatithe tuyeres are designated by reference numeral-I6, the axes of their base portions being normal to the furnace wall and the direction of discharge of the draft being offset 15 degrees from such axes as shown. The blasts are preferably discharged into the furnace substantially in a common plane perpendicular to the axis of the furnace so as to create a swirling draft as indicated at H. As above explained, the draft moves upwardly and for different conditions v straight and angled advantages dicated in the draft through the stock with the consequent mentioned in efllciency, increased production and improved product.

The tuyere angle, that is to say, the angle between the axis of the base portion of the tuyere and the angle of discharge of the blast theremay be, varied as desired. In Figure 4 l8 similar in all respects to the tuyre 8 except that the tuyere angle is 45. In Figure 5 is shown a similar tuyere ill but having a tuyere angle of 30. The tuyere angle will be selected in accordance with the size of the furnace, the number of tuyeres and the conditions of operation.

In Figure 7 is shown the draft effect produced by using tuyres l8 with a 45 tuyere angle. course this figure, as well as Figures 6 and 8, only gives a fair approximation of the result obtained, as the draft will spread out as it leaves the tuyere so-that substantially the whole of the stock column will be subjected to the draft before the gases have risen far. I have found that different tuyere angles are desirable and these may be determined by trial.

In Figure 8 there is shown diagrammatically a blast furnace having a series of tuyeres 3 having a 45 angle and a series of tuyeres i9 having a 30 angle, the respective and I9 alternating .around the furnace.

as assisting in spreading out the draft and thereby increasing the efficiency of the furnace, as in- Figure 8. In other cases, however, it is desirable that all the tuyeres have the same tuyere angle, as the use of tuyeres with different tuyere angles creates some impedance in the furnace due to crossing streams. angle or angles for any installation may be determined by trial. In some cases it may be desirable to use tuyeres in the same furnace, either alternately or otherwise, although this would .be theexception rather than the rule. -Such a furnace construc'tion'is shown in Figure 9, in which straight tuyeres 20 and angled tuyeres 2| are disposed alternately about the furnace. It is my present belief that the use of straight tuyeres is definitely detrimental and that angled tuyeres should be used entirely. Moreover, I consider it important that the tulleres be directed substantlally in, or at least not downwardly relatively to, a horizontal plane perpendicular to the axis of the furnace and passing through the axes of the base portions of the tuyeres. As stated above, if the blasts are directed downwardly the emciency of the furnace. is greatly reduced and undesirable conditions are brought about.

While I have present preferred shown and described certain embodiments of the invention and certain present preferred methods of practicing the same, it is to be that the inventionis not so limited but may be otherwise variously embodied and practiced within the scope of the following claims.

-I claim:

1. A blast furnace having a circumferential series of tuyeres discharging their blasts into the furnace eccentrically thereof and so as to certain of 'tuyeres i8 This provision is found to be desirable in some cases The best tuyere tively great portion distinctly understood iron in which pig-iron is tapped off at the bottom,

being directed at said tuyeres discharging their blasts at one predetermined acute'angle to the furnace wall and discharging their blasts at another predetermined acute angle to the furnace wall whereby to control and distribute the aft.

2. A method of operating a blast furnace, comprising introducing thereinto a circumferential series of blasts directed eccentrically of the furnace and substantially in a common plane perpendicular to the axis of the furnace, certain of said. blasts being directed at one predetermined angle to the furnace wall and other of said blasts another predetermined angle to the furnace wall, and thereby creating a controlled swirling inward and upward draft.

' furnace'for the production of pig-iron in which stock is charged in at the top and flows downwardly within the furnace and molten pig-iron is tappedoif at the bottom and in which the blasts discharged into the furnace by the tuyeres mingle free from interruption by any projecting interior furnace part, the improved method of increasing the uniformity of stock flow downwardly within the furnace and consequently increasing the efliciency and yield of the furnace, which comprises introducing into the furnace through its wall at its lower portion a generally circumferentially arranged series of blasts, directing at least a plurality of said blasts so that when discharged into the furnace they respectively move in a direction at an angle to a normal to the furnace wall, generally horizontally and in the same general direction with respect to the furnace wall and so as to create within the furnace a controlled swirling and upward draft which efflciently distributes the composite blast throughout a relaof the stock. f 4. A blast furnace for the production of pigstock is charged in at the top and flows downwardly within the furnace and molten the furnace its lower portion a series of openings in its wall arranged generally circumferentially thereof withtuyere holders arranged in such openings, the tuyere holders having tuyere receiving portions tapering from larger to smaller dimension in the direction side of the furnace and being arranged with their respective axes substantially normal to the furnace wall, and tuyeres having disposed within the tuyere holders whereby the tuyeres are held in place, the respective axes of said portions of the tuyeres being disposed substantially normal to the furnace wall, at least a plurality of the tuyeres being so' constructed as to discharge their blasts into the furnace angularly with respect to having at their respective axes, generally horizontally and.

KARL SYTEINBACHER.

taperedportions the tuyere receiving portions of.

furnace and conse-

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