EP0554673A2 - Bruleur pour un four à cuve - Google Patents

Bruleur pour un four à cuve Download PDF

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Publication number
EP0554673A2
EP0554673A2 EP93100370A EP93100370A EP0554673A2 EP 0554673 A2 EP0554673 A2 EP 0554673A2 EP 93100370 A EP93100370 A EP 93100370A EP 93100370 A EP93100370 A EP 93100370A EP 0554673 A2 EP0554673 A2 EP 0554673A2
Authority
EP
European Patent Office
Prior art keywords
nozzle
lance
burner according
disc
burner
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP93100370A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0554673A3 (enrdf_load_stackoverflow
Inventor
Léon Ulveling
Yvon Kroemmer
Carlo Pere
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Paul Wurth SA
Original Assignee
Paul Wurth SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Paul Wurth SA filed Critical Paul Wurth SA
Publication of EP0554673A2 publication Critical patent/EP0554673A2/fr
Publication of EP0554673A3 publication Critical patent/EP0554673A3/xx
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace
    • C21B5/001—Injecting additional fuel or reducing agents
    • C21B5/003—Injection of pulverulent coal

Definitions

  • the present invention relates to a burner for a shaft furnace.
  • a pulverized coal burner intended to be mounted in a pipe for injecting preheated air into a crucible of a blast furnace.
  • Such an injection pipe comprises, in a manner known per se, at least one nozzle penetrating into the crucible, a nozzle resting on the nozzle and an elbow mounted upstream of the nozzle.
  • This injection of pulverized coal is conventionally carried out by an injection lance in which the pulverized coal is suspended in an inert gas.
  • the oxidizer is either formed by the hot wind, enriched or not with oxygen, or by pure oxygen brought by a separate pipe near the mouth of the lance. In the latter case, pure oxygen is used to form a primary combustible mixture with the pulverized coal at the outlet of the lance, and the hot wind constitutes the secondary combustion air.
  • a lance capable of injecting both pure oxygen and pulverized coal will be called an "oxy-coal lance", while a lance injecting only oxygen will be called a "normal lance".
  • the injection lance is introduced obliquely through an opening in the mantle of the nozzle, that is to say of the tubular part which comes to rest on the nozzle.
  • the angle formed by the axis of the lance with the axis of the nozzle we can place the head from the lance at a distance more or less close to the mouth of the nozzle in the crucible.
  • the joint between the nozzle and the nozzle constitutes an obstacle for achieving very small angles between the axis of the nozzle and the axis of the lance.
  • the objective of the present invention is to provide a compact burner of simple construction which can be integrated into a device for introducing preheated air from a shaft furnace and which largely solves the problems mentioned above in relation with the combustion mechanism and in connection with the assembly of the spraying coal injection lances.
  • a burner comprising, in a manner known per se, a lance for injecting pulverized coal with a lance head provided with at least one outlet orifice for the pulverized coal, said lance being placed axially or almost axially in said nozzle so that said lance outlet orifice is located inside said nozzle at a distance L from the mouth of the nozzle in the crucible and which is characterized in that the head of said lance is supported in the axis of said nozzle by a part mounted, either in said nozzle, or directly upstream of said nozzle, and in that this part constitutes a deflector for the preheated air, so as to make it strongly turbulent near the outlet (s) of the lance.
  • the lance head is supported in the axis of said nozzle by a part mounted, either in said nozzle, or directly upstream of said nozzle.
  • This assembly has, as already mentioned above, the advantage that the head of the lance can be advanced far into the nozzle, theoretically even beyond the mouth of the nozzle in the crucible.
  • this arrangement has the advantage that the distance L between the head of the lance, or rather the outlet orifice of the pulverized coal, and the mouth of the nozzle in the crucible can be varied even during operation, by simple axial displacement of the lance. It is thus possible to determine experimentally said distance L during the operation of said burner, which would be difficult to do without the support piece of the present invention.
  • This adjustment of the distance L is, as we saw above, a very important factor on which we can play to optimize the combustion while avoiding blockage of the nozzles by ashes which stick to the walls of the latter.
  • the optimal distance L is a function in particular of the flow rate and of the physical and chemical characteristics of the pulverized coal. Hence the need to be able to easily modify, if possible during the operation of the burner, said distance L.
  • the axial introduction of the lance significantly increases the length of the latter which is directly in contact with the hot wind having a temperature of about 1200 ° C.
  • said lance support part simultaneously fulfills the role of a deflector acting on the air preheated to approximately 1200 ° C., for the make it highly turbulent in the vicinity of the outlet outlet (s). It thus succeeds in producing as close as possible to the lance head, a homogeneous mixture of the pulverized coal and the preheated air, that is to say bursting as soon as it leaves the pulverized coal / inert gas jet and d '' get a good distribution of solid particles in the preheated air flow flowing through the nozzle. The distance (resp. Time) required to obtain complete combustion is thus considerably reduced. This is all the more true for a jet of coal introduced axially, or almost axially, into the nozzle. The latter does indeed offer, as has already been pointed out, only a very small attack surface for the air flowing in the axial direction of the nozzle.
  • the turbulence created in the preheated air has above all also a very beneficial effect on the heterogeneous reaction between the solid residues of the pyrolysis reaction and the oxidizing gas. It follows that we manage to have a more complete combustion of the coal, even with high flow rates and a lance head close to the mouth of the nozzle.
  • deflectors can be envisaged to achieve this result. It should however be noted that it is advantageous to choose a type of deflector which gives the air a gyratory movement around the axis of the nozzle and to direct the air at the same time obliquely towards the jet.
  • a particularly interesting form of deflector is a deflector which divides the main flow of preheated air into separate jets which are deflected so as to form the generators of a fictitious hyperboloid of revolution which is coaxial with the nozzle and which is characterized by a convergent , a collar and a diverging.
  • the preheated air jets first converge on the jet of carbon to make it burst, then the jets diverge towards the walls of the nozzle and thus entrain the particles of coal on the entire section of the nozzle to then confer to the whole a turbulent gyratory movement towards the mouth of the nozzle in the crucible.
  • the deflector of the present invention also provides beneficial effects when used in conjunction with an "oxy-coal" lance of the type described above.
  • the turbulence of the preheated air in the vicinity of the lance head avoids the formation of layers of cold oxygen, which could constitute, at least near the lance head, a cold screen between the pulverized coal and the hot air, which would have a harmful effect on the kinetics of combustion.
  • the production of the deflector support in the form of a thick disc provided with a central bore to support the lance and peripheral bores with oblique axes to deflect the flow of hot air and make it turbulent is of a particularly execution robust and easy to make. It is for example feasible to produce this refractory ceramic disc.
  • Said deflector support can be easily adjusted in the opening of a nozzle at a distance more or less close to the mouth of the nozzle in the crucible.
  • the nozzle can also be placed directly upstream of the nozzle, which means that the latter must not have to be modified directly upstream of the nozzle.
  • it may have an external diameter substantially larger than the internal diameter of the nozzle, taking into account a deviation of the preheated air towards the axis of the nozzle.
  • the deflector-support is made of refractory ceramic, it can be adjusted directly in the metal sheath of the nozzle which allows to possibly gain a few centimeters on the outside diameter of the nozzle. It should be noted that the disc then fulfills a third function, namely that of local thermal insulation.
  • the conventional spherical joint between the nose of the nozzle and the nozzle may be omitted to make the deflector-support integral with the nozzle.
  • This ensures perfect centering of the lance head in the axis of the nozzle.
  • it will be necessary to provide an additional articulation in said preheated air injection pipe at a location upstream from the location of said deflector-support.
  • It may thus be advantageous to integrate said deflector-support in an intermediate sleeve fixed with one end to the nozzle and having at the other end a concave peripheral support surface, having substantially the shape of a crown cut out from a sphere in which the nozzle comes to rest with its nose which has a complementary convex bearing surface.
  • the present invention also proposes several advantageous embodiments to compensate for the forces that the relative angular displacements of the various elements of said air injection pipe can induce in the lance and in its two guide points.
  • FIG. 1 is a section through a vertical plane through a wall 14 of a blast furnace at the level of a pipe 10 of the type commonly used for blowing preheated air, that is to say hot wind, in the upper part of a blast furnace crucible 12.
  • This tubing 10 comprises in particular a nozzle 16 penetrating into the crucible 12 with its mouth 17, a cylindrical sleeve 20, called a nozzle, which comes to bear with one end on the nozzle 16 and an elbow 22 fixed to the other end of said nozzle.
  • a burner according to the present invention comprises a lance for injecting pulverized coal 24 provided with a lance head 28 with an outlet orifice 29, the construction of which is known per se, and a part 30 of new design.
  • the latter supports the head 28 of the lance 24 in the axis of said nozzle 16 and at the same time constitutes a deflector acting on the hot wind to make it highly turbulent in the vicinity of the outlet orifice of the lance.
  • said lance which is introduced by a sleeve 26 arranged in the elbow 22 of the tube 10, is, apart from alignment errors, coaxial with the nozzle 20 and the nozzle 16. It is supported, or rather guided , radially relative to its axis OO 'at the point of penetration into the elbow 22 by the sleeve 26, and in the immediate vicinity of its outlet orifice 29 by said part 30, while being able to move along said axis O-O '.
  • the part 30, shown in detail in FIGS. 3a and 3b has the shape of a disc 32 which has an upstream surface 34 facing the flow of hot air flowing through the nozzle, and a downstream surface 36 oriented towards the mouth 17 of the nozzle in the crucible and parallel to the surface 34.
  • These two surfaces 34 and 36 are connected by a lateral surface 38 which in the case of Figure 3b is cylindrical.
  • Figure 3c shows an alternative embodiment which is distinguished by the fact that the upstream 34 and downstream 36 surfaces are connected by a lateral surface 38 which has substantially the shape of a spherical crown. The usefulness of this spherical surface will be explained below.
  • a central bore 40 coaxial with the disc connects said upstream surface 34 to said downstream surface 36. Its diameter is slightly larger than that of the lance 24 in order to guarantee a certain radial clearance between the head 28 of the lance 24 and said part 30.
  • the bore 40 is advantageously provided with a frustoconical countersink 41 in order to facilitate the introduction of the lance 24.
  • these bores 42 are arranged around the bore 40 arranged several peripheral bores 42 intended to divide the flow of hot air striking the upstream surface 34 into several jets.
  • four of these bores 42 have been provided, however, there is nothing to prevent providing for example six or eight or another number.
  • These bores 42 which pass through the entire thickness of the disc 32, are characterized in that their axis is inclined towards the axis of the disc in the direction of flow of the preheated air. In this way the air jets obtained at the outlet of the part 30 are directed towards the jet of carbon which is at the outlet of the orifice 29 of the lance 24 coaxial with the disc.
  • these bores 42 can advantageously be made so as to have the shape of a truncated oblique skull whose large base cuts said upstream surface 34 and the small base said downstream surface 36 of the disk.
  • the axes of said peripheral bores are not only inclined towards the axis of the disc in the direction of flow of the preheated air, but they are also inclined circumferentially.
  • This execution can be described more explicitly as follows: the axes of the four peripheral bores (cylindrical or conical) determine four first points of intersection located 90 ° from each other with a first circumference of diameter D1 centered on said surface upstream 34 of the disc 32 and four second points of intersection with a second circumference of diameter D2 smaller than D1 centered on said downstream surface 36 of the disc, so that the trigonometric angle alpha ( ⁇ ), defined by the two passing planes by the axis of revolution of the disc and resp. by the first and the second point of intersection belonging to the same axis, ie the same for all the peripheral bores 42 of the disc 32.
  • ⁇ trigonometric angle alpha
  • FIG. 4 The deflection of the air jets obtained by this disc is shown schematically in FIG. 4.
  • said jets are represented by simple arrows (601, 602, 603, 604) in an isometric view.
  • the circumferences 62, 64 represent resp. said first circumference centered on the upstream surface 34 of the disc and said second circumference centered on the downstream surface 36 of the disc.
  • the points (621, 622, 623, 624) represent the points of entry of the air into the disc and the points (641, 642, 643, 644) the exit points.
  • Figure 4 shows that the jets thus deflected are generators of a hyperboloid of revolution coaxial with the disc 32 and having a neck 66.
  • the jets first converge at the outlet of the disc until 'said neck 66 to then diverge towards the internal wall of the nozzle.
  • the points of impact of the jets with the internal wall of the nozzle 16 are represented in FIG. 4 by the points (681, 682, 683, 684).
  • the rectilinear movement of the jets is transformed into a helical gyratory movement.
  • the beneficial effect of this movement of the four jets mainly lies in the combination of a first convergent movement of the air towards the jet of coal to burst the latter, with a second divergent movement which is transformed into a helical gyratory movement, to ensure an intense mixture of the oxidizer and the fuel.
  • the outlet orifice 29 of the lance must for this purpose be placed upstream of the neck 66 as shown in FIG. 4.
  • Figure 5 shows a first mode of mounting the part 30.
  • this part is adjusted in the central bore of a nozzle 16 whose transverse dimensions have been increased so as not to increase the flow resistance too much. hot air at room 30.
  • FIG. 6 shows an assembly identical to that of FIG. 5 where the part 30 has been adjusted more to the front of the nozzle 16. This makes it possible to move all the combustion in the crucible of the blast furnace, that is to say say in the area directly adjacent to the mouth of the nozzle. Since the combustion gases no longer flow inside the nozzle, the internal diameter of the latter does not necessarily have to be increased, which makes it possible to use a nozzle whose external gauge is identical to that of '' a classic nozzle.
  • Figure 7 shows an assembly in which the part 30 is adjusted in the nozzle 20 directly upstream of the nozzle 16.
  • This assembly makes it possible to work with a nozzle 16 which has a template substantially identical to that of a conventional nozzle, it can therefore be used with 18 eardrums already installed on a blast furnace.
  • the nozzle 20 formed of an outer metallic mantle 91, and of an internal refractory lining 89 is fixed by a flange 90 integral with said mantle 91 to the nozzle 16. It is noted that at the place where the part 30 is adjusted in the refractory nozzle 89 has been removed so that the part 30 is directly adjusted in the outer metallic mantle 91.
  • a refractory ceramic material is chosen to manufacture the part 30, the latter locally replaces said refractory lining 89.
  • Figure 8 shows an assembly method similar to the previous one.
  • the part 30 is however not adjusted in said nozzle 20, but in an intermediate metal sleeve 80 which is fixed with its downstream end by means of a flange 82 on said nozzle 16.
  • said sleeve 80 is provided with a concave peripheral support surface 84, having substantially the shape of a crown cut out from a sphere in which the nozzle 20 comes to bear with its nose 86 which has a convex support surface complementary to surface 84. This re-establishes the classic ball joint which has proven its worth for the connection of the nozzle to the nozzle.
  • the part 30 must be blocked by appropriate means to avoid rotation around the lance, since the part 30 is subjected to non-negligible circumferential forces due to the circumferential deviation of said jets.
  • the part 30 Since the manufacture of the part 30 requires only very simple machining operations, it can be easily machined, for example in a refractory ceramic material.
  • This articulation can simply be produced by a part 30 as shown in FIG. 3c and which has already been described above.
  • the spherical annular surface 38 then allows said part 30 to be placed in a slightly oblique manner in the nozzle, the nozzle or the sleeve, in the case where the axis of the lance is not aligned with the axis of the nozzle or the axis of the nozzle.
  • the bore 40 which serves as a support for the lance, slightly larger than the outside diameter thereof so as to allow the lance to be placed obliquely in this bore 40.
  • the bore 40 can be made (as shown in Figure 3d) so as to present towards said upstream surface 34 towards said downstream surface 36 a converging part, a neck slightly larger than the diameter of the lance and a divergent part. The lance housed in said neck can then be easily inclined relative to the axis of the disc.
  • FIG. 3a, 3b, 3c and 3d The execution of said deflector support in the form of a disc as shown in Figures 3a, 3b, 3c and 3d constitutes a preferred embodiment which, as we have seen above, has many advantages including, for example, its robustness and the simplicity with which it can be made. It is however also possible to adopt a more complicated shape, that is to say more aerodynamic for said deflector support.
  • Figure 2 shows by way of example a deflector support 50 which comprises an outer ring 52 and inner ring 54, and curved vanes 58 connecting these two rings.
  • the outer ring 52 can be adjusted for example in the nozzle 16.
  • the inner ring 54 supports the lance in its central bore 56.
  • the blades 58 act as a spacer between the two rings 52 and 54 and confer by their shape aerodynamic at the same time to the flow of hot air a gyratory movement around the axis of the lance.
  • Figures 9 and 10 show another alternative embodiment of the burner for the proposed shaft furnace.
  • the reference 116 identifies a special nozzle provided with an upstream cylindrical chamber 118, of diameter slightly larger than the downstream outlet orifice 117 of the nozzle.
  • this chamber 118 is adjusted a deflector-support 130 so as to be able to slide axially in the chamber 118.
  • the reference 124 marks a lance for injecting pulverized coal, the lance head 128 of which is integrated in the deflector-support 130.
  • the latter is therefore integral with the lance 124 and can be moved axially in the chamber 118 by an axial displacement. of the lance 124.
  • the deflector-support is shown in solid lines in a downstream position, in which it bears on a shoulder 119 axially delimiting the chamber 118 on the side of the outlet orifice downstream 117, and in broken lines near an upstream inlet section of the chamber 118.
  • the deflector-support 130 shown in Figure 9, has the shape of a truncated cone flaring in the direction of the flow of preheated air from the lance head 128 to take support , via a peripheral surface 138 on a cylindrical surface delimiting the chamber 118.
  • This shape of the deflector-support 130 has, among other things, the advantage of facilitating the arrangement around the lance head 128 of bores peripherals 142 'and 142' ', made in the deflector-support 130 to divide the flow of preheated air into several jets and to orient these isolated jets towards the flow of pulverized coal.
  • the present invention undoubtedly contributes to better mastering the various problems associated with the injection of pulverized coal into the crucible of a blast furnace or a pot furnace. It will be especially appreciated that the solution proposed constitutes by its simplicity and its clever design a solution particularly adapted to the demanding environment of a blast furnace. The informed reader will also be able to appreciate the multiple beneficial effects that the present invention brings with regard to the optimization of the combustion mechanism of pulverized coal in the crucible of a blast furnace.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Blast Furnaces (AREA)
EP93100370A 1992-02-05 1993-01-13 Bruleur pour un four à cuve Withdrawn EP0554673A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
LU88065 1992-02-05
LU88065A LU88065A1 (fr) 1992-02-05 1992-02-05 Bruleur pour un four a cuve

Publications (2)

Publication Number Publication Date
EP0554673A2 true EP0554673A2 (fr) 1993-08-11
EP0554673A3 EP0554673A3 (enrdf_load_stackoverflow) 1994-03-09

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EP93100370A Withdrawn EP0554673A2 (fr) 1992-02-05 1993-01-13 Bruleur pour un four à cuve

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EP (1) EP0554673A2 (enrdf_load_stackoverflow)
LU (1) LU88065A1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU91264B1 (en) * 2006-07-12 2008-01-14 Wurth Paul Sa Pulverized coal injection lance

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1171136A (fr) * 1957-04-11 1959-01-22 Siderurgie Fse Inst Rech Perfectionnements aux tuyères de four à cuve et en particulier aux tuyères de haut fourneau
FR1280598A (fr) * 1960-06-21 1962-01-08 Pompey Acieries Dispositif d'injection de substances liquides, semi-liquides, pulvérulentes, fluidifiées ou analogues
FR1316711A (fr) * 1961-12-22 1963-02-01 Mobil Oil France Brûleur perfectionné
FR1559679A (enrdf_load_stackoverflow) * 1967-12-08 1969-03-14
GB8506655D0 (en) * 1985-03-14 1985-04-17 British Steel Corp Smelting shaft furnaces

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU91264B1 (en) * 2006-07-12 2008-01-14 Wurth Paul Sa Pulverized coal injection lance
WO2008006764A1 (en) * 2006-07-12 2008-01-17 Paul Wurth S.A. Pulverized coal injection lance
EA014345B1 (ru) * 2006-07-12 2010-10-29 Поль Вурт С.А. Форсунка для вдувания угольной пыли
US8080200B2 (en) 2006-07-12 2011-12-20 Paul Wurth S.A. Pulverized coal injection lance

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Publication number Publication date
LU88065A1 (fr) 1993-08-17
EP0554673A3 (enrdf_load_stackoverflow) 1994-03-09

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