JP4742770B2 - Top blowing lance and converter operation method using the same - Google Patents

Description

  The present invention uses an upper blowing lance for supplying an oxidizing gas into the converter when decarburizing and refining molten steel and / or dephosphorizing blowing hot metal using a converter, and the upper blowing lance. The present invention relates to a converter operation method.

  In a steelmaking process, decarburization refining is performed as a known technique by containing molten steel in a converter and supplying an oxidizing gas. A gas containing oxygen is used as the oxidizing gas, and oxygen gas is widely used industrially. By supplying the oxidizing gas into the converter in this way, C in the molten steel accommodated in the converter reacts with O in the oxidizing gas to perform a decarburization process.

In the decarburization treatment, as represented by the following formula (1), C in molten steel reacts with O in oxidizing gas to generate CO (hereinafter referred to as primary combustion), and primary combustion. The reaction of the following formula (2) (hereinafter referred to as secondary combustion) in which CO produced by the above reaction and O in the oxidizing gas react to produce CO ₂ proceeds.
C + 1 / 2O ₂ → CO (1)
CO + 1 / 2O ₂ → CO ₂ (2)
Here, the proportion of O in the oxidizing gas supplied into the converter that contributes to secondary combustion is defined as the secondary combustion rate by the following equation (3) (however, CO ₂ and CO on the right side) Are the volumes of CO ₂ and CO in the exhaust gas, respectively).
Secondary combustion rate = CO ₂ / (CO + CO ₂ ) (3)
Comparing the reaction heat generated by the primary combustion and the reaction heat generated by the secondary combustion, the secondary combustion is about 2.5 times the primary combustion. Therefore, when the secondary combustion rate is lowered, the temperature of the furnace wall at the upper part of the converter is lowered. If the operation of the converter is continued in this state, the metal is accumulated and not only the volume in the furnace is reduced but also the yield of steel is reduced.

  On the other hand, when the secondary combustion rate is increased, the calorific value increases and the temperature in the furnace rises, so that heat can be applied to the molten steel and the metal can be melted. On the other hand, it is possible to shorten the blowing time by reducing the secondary combustion rate and increasing the oxygen used for the dereaction represented by the formula (1). These are generally performed by controlling an oxidizing gas jet (soft blow / hard blow) supplied from an upper blow lance.

  On the other hand, in the steelmaking process, to reduce the load in the converter (reduction in the amount of steelmaking slag) and reduce the total cost of steelmaking, before the decarburization blowing of Si and P contained in the hot metal in the converter A removal method using an oxidizing agent (hereinafter referred to as a flux) is taken in advance, and one of the methods is dephosphorization blowing using a converter as a processing vessel.

  In general, dephosphorization blowing using a converter is similar to decarburization refining, in which an oxidizing gas typified by oxygen gas is blown from the upper surface of the steel bath through an upper blowing lance and a refining agent such as lime (hereinafter referred to as “refining”) (Referred to as flux) is added to the furnace. At this time, the oxidizing gas supply rate from the top blowing lance, the lance height, etc. are adjusted and sprayed with soft blow as compared with decarburization blowing, and the T.O. A technique for controlling the Fe concentration is taken.

  As described above, in the processing using the converter vessel that requires the top blowing lance, the primary combustion, the secondary combustion, the T.P. Fe control and the like can be performed.

  At this time, the jet flow control from the lance nozzle is usually performed by adjusting the flow rate of the oxidizing gas, the lance height, etc., as disclosed in Patent Document 1. In addition, one of the jet flow controls is the use of a control flow different from the main jet of the lance nozzle. For example, Patent Document 2 discloses a lance nozzle and a converter operation method in which gas blowing holes are provided in the inner surfaces of the throat portion and the outlet portion of the Laval nozzle, the area ratio of the Laval nozzle is controlled, and proper expansion is possible even at a low flow rate. ing.

  However, although the technique disclosed in Patent Document 2 can achieve an increase in the jet flow velocity from the nozzle, it cannot perform control that greatly reduces the flow velocity. In addition, since the inclination angle of the normal nozzle cannot be changed arbitrarily once it is determined, the nozzle inclination angle must be set according to the position of the attached metal in order to dissolve the metal, etc. Therefore, there is a problem that the lance cost increases because the nozzle must be changed. Moreover, if the tilt angle is too wide, damage to the furnace wall refractory also becomes a problem.

In order to solve such a problem, a technique capable of arbitrarily changing the inclination angle of the lance is suitable. As such a technique, Patent Document 3 discloses a chamber disposed at the tip of the nozzle of the top blowing lance. A technique for changing the angle of the oxygen jet by disposing a conduit on the side wall and supplying gas from the conduit is disclosed. However, the technique disclosed in Patent Document 3 is a technique in which the agitation of the metal bath proceeds by changing the impact point at which the supersonic oxygen jet collides with the surface of the metal bath (that is, the molten metal bath) over time. A dramatic improvement in the secondary combustion rate cannot be expected.
JP-A-7-70626 JP 2000-234116 A Japanese Patent Publication No.8-111807

  The present invention has been made in view of such circumstances, and a lance nozzle tip is used by using one lance nozzle when performing decarburization refining of molten steel and / or dephosphorization blowing of hot metal using a converter. Controlling the oxidizing gas jet without changing the lance height and oxidizing gas flow rate, melting the adhering metal in the furnace, molten steel heat-up by increasing secondary combustion, and high-speed blowing An object of the present invention is to provide a lance nozzle and a converter operating method using the lance nozzle.

In order to solve the above problems, the present invention provides the following (1) to ( 11 ).
(1) An upper blowing lance having one or more gas injection nozzles having a throat portion at an inlet portion and a divergent portion downstream of the throat portion, wherein at least one of the gas injection nozzles may possess the diverging portion in at least one location control gas supply hole disposed on the opposite side of the wall the direction to try to deflect the jet to be injected from the gas injection nozzle of the nozzle, and, The ratio x / l of the distance x from the throat portion outlet to the center of the control gas supply hole and the distance l from the throat portion outlet to the nozzle outlet is 0.3 ≦ x / l <1.0, An upper blow lance characterized in that the direction and / or flow velocity of the jet flow ejected from the gas injection nozzle is controlled by supplying the control gas from the control gas supply hole.
( 2 ) In the above (1) , the ratio between the gas flow rate Qs (Nm ³ / min) supplied from the control gas supply hole and the gas flow rate Qm (Nm ³ / min) supplied from the gas injection nozzle Is an upper blowing lance characterized by 0.02 ≦ Qs / Qm ≦ 0.3.
( 3 ) In the above (1) or (2) , a plurality of the gas injection nozzles are provided, and the control gas supply hole connects the center point of the injection port of each gas injection nozzle and the center point of the lance cross section. An upper blowing lance arranged on a straight line.
( 4 ) In the above ( 3 ), the control gas supply hole supplies a control gas from the center side of the lance to the gas injection nozzle.
( 5 ) The upper blow lance characterized in that the control gas supply hole of ( 3 ) supplies the control gas to the gas injection nozzle from the radially outer side of the lance.
( 6 ) In the above (1) or (2) , a plurality of the gas injection nozzles are provided, and the control gas supply hole is formed so as to supply control gas to each gas injection nozzle from the center side of the lance. Top blow lance, characterized by
( 7 ) In the above (1) or (2) , a plurality of the gas injection nozzles are provided, and the control gas supply holes are formed so as to supply control gas to the gas injection nozzles from the outside of the lance. Top blow lance characterized by that.
( 8 ) In the above (1) or (2) , a plurality of the gas injection nozzles are provided, and the control gas supply holes are supplied from the center side of the lance to the injection nozzles and from the outside of the lance. An upper blowing lance formed so as to be able to selectively supply a control gas to a gas injection nozzle.
( 9 ) One or more gas injection nozzles having a throat portion at the inlet portion and a divergent portion on the downstream side of the throat portion are disposed, and at least one of the gas injection nozzles includes the nozzle of the nozzle have at least one position control gas supply holes of the disposed on the opposite side of the wall the direction to try to deflect the jets to be injected from the gas injection nozzle of a divergent portion, and the from said throat portion outlet using the distance x between the control gas supply hole center, a lance on the ratio x / l and the distance l between the nozzle exit from the throat outlet Ru 0.3 ≦ x / l <1.0 der A converter operation method in which an oxidizing gas is supplied into a converter to perform a predetermined operation, and is controlled from a gas supply hole for controlling the gas injection nozzle in a part or all of the processing in the converter. The gas is injected Converter operation method characterized by controlling the direction and / or flow rate of the jet ejected from the morphism nozzle.
(10) inlet portion have a plurality of gas injection nozzle having a diverging section having a throat portion and the downstream side of the throat portion, opposite to the direction it is intended to deflect the jets injected from the gas injection nozzle A plurality of control gas supply holes arranged on the side wall surface, and a distance x between the throat portion outlet and the control gas supply hole center and a distance l between the throat portion outlet and the nozzle outlet in converter operation method of supplying an oxidizing gas to the converter furnace with the upper lance ratio x / l is Ru 0.3 ≦ x / l <1.0 der with, among the gas injection nozzle A converter operating method characterized by scanning the injection direction of the oxidizing gas injected from at least one along a straight line direction connecting the injection nozzle center point of the gas injection nozzle and the center point of the lance cross section. .
( 11 ) In the above ( 9 ) or ( 10 ), the oxidizing gas is supplied into the converter using the gas injection nozzle, and the molten steel is decarburized or the molten iron is dephosphorized. A converter operating method, comprising melting a metal that has adhered to a furnace wall of the converter.

  According to the present invention, at least one gas injection nozzle is premised on an upper blow lance having one or more gas injection nozzles having a throat portion at an inlet portion and a divergent portion downstream of the throat portion. , At least one control gas supply hole is disposed on the wall surface of the divergent portion, and the control gas is supplied therefrom, whereby the direction and / or flow velocity of the jet injected from the gas injection nozzle is controlled. Therefore, soft blow and hard blow can be arbitrarily adjusted, and it is possible to improve the processing capacity of dephosphorization processing and decarburization processing using a converter. For this reason, a dramatic advancement of the refining function can be achieved.

Hereinafter, the present invention will be described in detail.
First, the principle of the present invention will be described.
One of the elements using the fluid phenomenon is a fluid element, and the principle of the present invention uses this fluid element. A fluid element is a generic term for elements that utilize the functions obtained by the effect of the interference between the jet and the side wall, the collision effect between the jet and the jet, the fluid phenomenon caused by the vortex, and the effect of the flow velocity fluctuation of the jet itself. Research is being done in the field. For example, the control nozzle is arranged in the lateral direction at the outlet of the main nozzle. When fluid is introduced from the control nozzle to the main nozzle, a vortex is generated between the main flow and the side wall. This vortex has a pressure lower than the atmospheric pressure, and a force is generated by the differential pressure between the average value of the static pressure distribution of the vortex and the atmospheric pressure, and the main flow flows along one of the side walls.

  However, research on fluidic devices is basically conducted under laminar flow conditions, and there has been little research on supersonic fluidic devices to which the present invention is applied. The present invention applies this fluid element to an upper blowing lance nozzle using a supersonic jet which has been hardly studied in the fluid element.

  In order to confirm the principle of the present invention, the inventors have provided a gas supply hole between the throat portion and the outlet portion of the Laval nozzle, and the particle image flow velocity is affected by the influence of the control flow (working gas) on the jet characteristics from the Laval nozzle. The flow rate was measured with a meter. FIG. 1 is a schematic diagram showing an experimental apparatus for confirming the principle of the present invention used at this time.

  In this apparatus, a Laval nozzle 4 provided with a control flow introduction hole 5 is attached to a base 10 and a laser irradiation apparatus 1 for irradiating a laser 3 to a jet 6 jetted downward from the Laval nozzle 4 and a camera for measuring the jet. 2 is installed.

  Further, the nozzles used in the above-described principle confirmation survey of the present invention are schematically shown in FIGS. Here, a single-hole conical Laval nozzle was used for flow velocity measurement. In the figure, reference numeral 11 denotes a throat portion, 12 denotes a divergent portion, and 15 denotes a working gas (control gas) supply hole. Further, x is the distance between the centers of the throat portion outlet (the boundary position between the throat portion 11 and the divergent portion 12) and the working gas (control gas) supply hole 15, and l is the distance between the throat portion outlet and the nozzle outlet (ie, the divergent portion length). ) Dm is the throat diameter, ds is the diameter of the working gas (control gas) supply hole 15, and D is the nozzle outlet diameter. In each nozzle, a hole of Φ5 mm was formed from the jet ejection direction and 90 ° direction, and a control flow (working gas) was introduced. Type-A operates just below the nozzle extension (2.5 mm from the throat outlet), type-B operates at the center of the extension (5.0 mm from the throat outlet), and type-C operates near the nozzle outlet (6.5 mm from the throat outlet). The gas introduction position was changed. Table 1 shows the dimensions of each nozzle.

Table 2 shows the gas flow conditions in this study. N ₂ gas was used as the gas type. In each nozzle, the main gas flow rate was changed between 2.0 and 4.0 Nm ³ / min. Further, under the condition of the main gas flow rate being constant, the working gas flow rate was changed to 0.0, 0.5, and 1.0 Nm ³ / min, and the flow velocity distribution of the jet was measured.

  As a result of the investigation, the flow velocity distribution of the jet flow from each nozzle is shown in FIG. As shown in FIG. 3, it can be seen that the direction and flow velocity of the jet can be changed by introducing the working gas.

Specifically, in type-B, the introduction of the working gas clearly observed jet (jet) deflection and a decrease in flow velocity value. It should be noted here that when the working gas is introduced, the jet is deflected in the direction opposite to the introduction direction. This is the opposite direction to the knowledge obtained with the conventional eccentric rapid expansion nozzle. Further, when the working gas flow rate is compared conditions ^{Qs = 0.5Nm 3 /min,1.0Nm 3 / min} , the deflection of the jet is increased is more of Qs = 0.5 Nm ³ / min, even the maximum flow rate value Qs = 0.5 Nm ³ / min was lower.

Further, when the working gas was introduced into the type-C nozzle, the jet deflection was further increased as compared with type-B, and the flow velocity value was also significantly reduced. Further, when likewise working gas flow rate and type-B compares the condition of ^{Qs = 0.5Nm 3 /min,1.0Nm 3 / min} , the deflection of the jet is increased is more of Qs = 0.5Nm ³ / min Also, the maximum flow velocity value was lower when Qs = 0.5 Nm ³ / min.

On the other hand, in type-A, even when working gas was introduced, jet deflection was extremely small. In the case of Qm = 2.0 Nm ³ / min, the maximum flow rate value increases as the working gas flow rate increases. This is because the working gas flow rate is excessive with respect to the main gas flow rate, and the total flow rate is large. This is because it increases. Thus, it was confirmed that there is a difference in effect depending on the position where the working gas is introduced.

  FIG. 4 shows an axial flow velocity distribution diagram of the jet flow from each nozzle. From FIG. 4, the jet flow velocity decreases as the distance from the nozzle outlet increases under each condition, but with the type-A nozzle, the jet flow velocity value does not change much regardless of whether or not the working gas is introduced. It was. In the type-B nozzle, the flow velocity decreased from the vicinity of the nozzle outlet due to the introduction of the working gas, and in the type-C, the flow rate further decreased significantly. Further, under the condition of the same working gas ratio (Qs / Qm), the jet attenuation was larger as the working gas hole was closer to the nozzle outlet.

  From the radial distance indicating the maximum flow velocity value of the jet at each nozzle and the axial distance, the jet deflection angle β when working gas was introduced was calculated geometrically. Since it has been found that the jet deflection angle is arranged by the main gas / working gas flow rate ratio regardless of the main gas flow rate, the calculation was performed based on this assumption. FIG. 5 shows the relationship between the jet deflection angle β and the working gas ratio Qs / Qm.

  When the deflection angle is compared for each type of nozzle, type-C into which the working gas is introduced at a position closest to the nozzle outlet has the largest deflection angle. In type-B and type-C, jet flow deflection occurred when the working gas ratio Qs / Qm was 0.02 or more, and the deflection angle was maximum when Qs / Qm = 0.125. Thereafter, the deflection angle decreased and became almost constant when Qs / Qm ≧ 0.3.

  Even if the working gas ratio is increased with the type-B and type-C nozzles in this study, the deflection angle of the jet does not increase, but the reason for the slight decrease is as follows.

FIG. 6 shows the relationship between the jet deflection angle, the main flow, and the difference (Pm−Ps) in the working gas nozzle introduction pressure Pm, Ps (kgf / cm ² ). The figure shows that the jet deflection angle decreases as the pressure difference between the main flow and working gas flow decreases. Thus, when the working gas ratio is increased, the flow from the working gas hole becomes stronger than the main flow, and the working gas flow is the main flow in the nozzle. As a result, the jet deflection angle decreases.

  FIG. 7 shows a comparison of jet deflection angles when the working gas introduction position changes under the same flow rate condition. Here, the ratio of the throat outlet to the working gas hole center distance (x) (x / l) with respect to the length of the nozzle end spread part was used on the horizontal axis, where the throat part outlet was 0. From this figure, the value of x / l becomes larger than 0.25, that is, the closer the working gas hole is to the nozzle outlet, the larger the deflection is in the direction opposite to the working gas introduction direction, and vice versa. There is little deflection in the direction of gas introduction.

  The reason why this phenomenon occurs can be explained as follows. In type-A, in which the working gas hole is close to the throat diameter, a circulating flow (vortex) is formed immediately below the working gas hole due to the gas flow from the side. As a result, a pressure drop near the working gas side wall surface occurs, It is thought that it becomes pressure. In the vicinity of the nozzle outlet, it is ejected while being pushed against the wall opposite to the working gas hole on the opposite side of the working gas hole, but on the one side of the working gas hole, the working gas hole side and the opposite side are ejected. Due to the pressure difference, a force directed toward the working gas hole is generated, and deflection toward the working gas hole occurs. However, since the main jet is supersonic, its force is weak compared to the downward jet output of the main jet, and as a result, the jet is ejected in a slightly divergent shape after the nozzle exit, and apparently deflected. Very small.

  On the other hand, when the working gas hole is close to the nozzle outlet as in the type-B and C nozzles, the jet is pushed against the wall surface on the side opposite to the working gas hole by the working gas flow. At this time, since the nozzle outlet is directly under the working gas hole, a circulating flow is not formed (even if formed), and as a result, the jet is ejected while being pushed against the wall surface on the side opposite to the working gas hole. The

  From the above, it has been clarified that as the working gas introduction position is closer to the nozzle outlet, the deflection of the jet increases and the attenuation of the angular jet increases.

  From the above investigation results, in the present invention, as shown in FIG. 8, a Laval nozzle provided with one gas injection nozzle 13 having a throat portion 11 at the inlet portion and a divergent portion 12 downstream of the throat portion. The control gas supply hole 15 is provided on the wall surface of the divergent portion 12 of the gas injection nozzle 13 and the control gas 16 is supplied from the control gas supply hole 15. Thus, the direction and flow velocity of the jet (jet) 17 injected from the gas injection nozzle 13 are controlled.

  In such an upper blow lance 14, the jet flow ejected from the gas injection nozzle 13 by changing the position of the control gas supply hole 15 of the gas injection nozzle 13 which is a Laval nozzle or the flow rate of the control gas as described above. The jet direction and flow velocity of the (jet) 17 can be freely changed.

  In the top blowing lance of the present invention, the number of spray nozzles is not limited to one, and may be plural. In this case, it is desirable to provide a control gas supply hole in at least one nozzle arranged in a position where it is desired to change the jet direction of the jet (jet) among the gas injection nozzles. At this time, it is necessary to arrange | position the supply hole of control gas in the direction opposite to the position which wants to change a gas injection nozzle from the above-mentioned investigation result. Of course, control gas supply holes may be provided in all the nozzle holes of the plurality of injection nozzles. Furthermore, the number of control gas supply holes provided in one injection nozzle is not limited to one and may be plural. For example, as shown in FIG. 9, by providing two control gas supply holes 15a and 15b so as to face the divergent portion 12 of the Laval nozzle 13, not only the deflection direction of the jet flow (jet) but also It can be changed in the opposite direction, and the degree of freedom of application can be further increased.

Further, from the above investigation results, the ratio x / l between the distance x between the throat portion 11 of the gas injection nozzle 13 and the center of the control gas supply hole 15 and the distance l between the throat portion 11 and the nozzle outlet is 0. 3 ≦ x / l <1.0 is appropriate. Further, the ratio of the gas flow rate Qs (Nm ³ / min) supplied from the control gas supply hole 15 to the gas flow rate Qm (Nm ³ / min) supplied from the gas injection nozzle is 0.02 ≦ Qs / A range of Qm ≦ 0.3 is appropriate.

  When the lance has a plurality of gas injection nozzles, it is more effective to dispose the control gas supply holes on a straight line connecting the injection port center point and the center point of the lance cross section. For example, as shown in FIG. 10, when a plurality (four in this example) of gas injection nozzles 22 are provided in the lance nozzle 21, the injection nozzle center point No of the gas injection nozzle and the center of the cross section of the lance 21 A control gas supply hole 23 is disposed on a straight line connecting the point Lo. This is because when the control gas is introduced, the jetting direction of the jet changes to the radial side of the cross section of the lance nozzle, and the same effect is obtained as if the inclination angle of the nozzle is deflected. This is because it is possible to control the interference of the jet from the wide range. In the case of FIG. 10, the control gas supply holes 23 are disposed on the inner side, but may be disposed on the outer side as shown in FIG. In the case of FIG. 10, since the jet flow from each gas injection nozzle 22 is deflected outward, the jet flow spreads outward and becomes soft blow. In the case of FIG. 11, the jet flow from each gas injection nozzle 22 merges and becomes hard. Become a blow. In this case, if each nozzle shown in FIG. 9 is used, both soft blow and hard blow can be realized. Although it is preferable to arrange the control gas supply hole on a straight line connecting the injection nozzle center point and the center point of the lance cross section, the control gas supply hole is not necessarily located at the injection port center point and the center point of the lance cross section. Even if the control gas supply holes of the gas injection nozzles face inward or outward, a certain degree of effect can be obtained.

  In the present invention, by introducing the control flow into the jet flow from the gas injection nozzle, the jet flow velocity can be greatly changed from supersonic speed (hard blow) to subsonic speed (soft blow). For this reason, the improvement in heat receiving due to the increase in the amount of secondary combustion by soft blow, and the T.V. Since Fe can also be controlled, it can be applied to hot metal dephosphorization. In such soft blow, a plurality of gas injection nozzles 22 are arranged as shown in FIG. 10 described above, and a control gas supply hole 23 is arranged on the inner side thereof to expand the jet flow outward and reduce the flow velocity of the jet flow. Can be realized.

  In the decarburization process of molten steel, the jet flow velocity is set to supersonic (hard blow). However, if the jets of a plurality of gas injection nozzles are deflected in the direction in which the jets from the nozzles are combined, the jet flow is attenuated. Can also be suppressed. Such hard blow can be realized by disposing a plurality of gas injection nozzles 22 as shown in FIG. 11 described above, disposing control gas supply holes on the outside thereof, and deflecting the jet flow inward. .

  The section for supplying the control gas may be a part of all the processing sections (either the first half, the middle, or the second half or more) in both the dephosphorization and decarburization processes, or may be supplied in the entire processing section.

  Furthermore, if the jet is deflected so as to expand in the radial direction, the metal that has adhered to the furnace wall of the converter can be melted by the effects of both deflection and jet attenuation.

  Thus, in the present invention, the gas injection nozzle (lance nozzle) can be applied to a wide range of uses without being replaced each time.

<First embodiment>
The dephosphorization behavior, the secondary combustion behavior, and the metal dissolution behavior when the hot metal was dephosphorized using the 300 ton scale top-bottom blowing converter shown in FIG. 12 were investigated. In addition, the hot metal used the temperature of 1200-1260 degreeC. The operating conditions are as shown in Table 3.

  In FIG. 12, reference numeral 31 denotes an upper bottom blowing converter, and a bottom blowing tuyere 34 is provided at the bottom, and an upper blowing lance 36 is inserted from above the converter 31. A steel outlet hole 39 is provided on the side wall of the converter 31. An exhaust gas dust collection facility 35 is provided above the converter 31 so as to cover the opening. The exhaust gas dust collecting equipment 35 is provided with an upper blowing lance insertion hole 37. Hot metal 33 is stored in the converter 31, and a slag 38 is floating on the hot metal 33. A bare metal 32 is attached to the inner wall at the top of the converter 31.

  Oxygen gas was supplied as an oxidizing gas from the top blowing lance. Nitrogen gas was supplied as the bottom blowing gas.

  Table 4 shows the implementation conditions of the top blowing lance nozzle of the present invention example and the comparative example. As the lance nozzle, a four-hole Laval nozzle having four nozzle injection holes was used. In Example 1 of the present invention, the control gas was supplied from the center of the lance nozzle to all the gas injection holes (nozzles) in the direction connecting the center point of the lance and the center point of each gas injection nozzle, as in FIG. The control gas was supplied to all gas injection holes from the center of the lance nozzle. The control gas was supplied from a position where the ratio x / l of the length of the throat portion and the end spread portion of the Laval nozzle was 0.25. The control gas flow rate Qs was supplied at a ratio of 0.5 to the flow rate Qm from the main gas injection hole. In Invention Example 2, as in Invention Example 1, control gas is supplied to all gas injection holes from the center of the nozzle to all gas injection nozzles in the direction connecting the lance center point and the center point of each gas injection hole. did. The control gas was supplied from a position where the ratio x / l of the length of the throat portion to the end spread portion of the Laval nozzle was 0.5. The control gas flow rate Qs was supplied at a ratio of 0.5 to the flow rate Qm from the main gas injection hole. In Invention Example 3 as well as Invention Example 1 and Invention Example 2, control gas is supplied to all gas injection holes in the direction connecting the nozzle center point and the center point of each gas injection hole from the nozzle center to all gas injection holes. I tried to supply. The control gas was supplied from a position where the ratio x / l of the length of the throat portion to the end spread portion of the Laval nozzle was 0.5. The control gas flow rate Qs was supplied at a ratio of 0.1 to the flow rate Qm from the main gas injection hole. In the above invention examples 1 to 3, the supply of the control gas was performed in the entire section of the process.

Further, in Invention Example 4, the nozzle arrangement was the same as in Invention Example 3, and the arrangement of the control gas supply holes was also the same as in Invention Example 3. The control gas flow rate Qs was supplied at a ratio of 0.1 with respect to the flow rate Qm from the main gas injection hole, from the position where the ratio x / l of the nozzle throat portion to the end spread portion length becomes 0.5. The control gas was supplied only in the first half of the process (up to a process progress of 50%). As described above, the lance conditions of Invention Examples 1 to 4 were set to a total acid feed rate of 27000 Nm ³ / h and a lance height of 2.5 m (see Table 4).

On the other hand, in Comparative Example 1, a normal Laval nozzle that does not supply control gas was used. The total acid feeding speed was 27000 Nm ³ / h, and the lance height was 2.5 m. In Comparative Example 2, as in Comparative Example 1, a normal Laval nozzle that does not supply a control gas was used, and the first half of the treatment (50% of the entire treatment section) was processed at a half-half acid feed rate. Each is dephosphorized for 10 minutes as shown in Table 5, dephosphorization behavior (dephosphorization rate), degree of slag (% T. Fe), secondary combustion rate (= (% CO ₂ ) / ((% CO ) + (% CO ₂ ))), and the dissolution behavior of the bullion was investigated. Here, the total acid feed rate indicates the sum of oxygen gas supplied per unit time from the main gas injection hole and the control gas supply hole.

  The results are shown in Table 5. In the present invention example 1 in which the control gas is supplied from the nozzle center to all the gas injection holes in the direction connecting the nozzle center point and the center point of each gas injection hole, the T.I. The Fe concentration is increased with respect to Comparative Example 1, and the dephosphorization rate is slightly increased. Further, the secondary combustion rate during processing is also higher than that of Comparative Example 1.

  In addition, the control gas is supplied from the position where the ratio x / l of the length of the throat portion and the diverging portion length of the Laval nozzle is 0.5, and the soft blow of the jet is promoted compared to the first embodiment. , Secondary combustion rate during processing, and T. The Fe concentration is further increased and the dephosphorization rate is also improved. In addition, since the jet flow was deflected to the furnace wall by the control gas derivation, the metal in the furnace was well dissolved. Further, the control gas is supplied from a position where the ratio x / l of the length of the throat portion to the divergent portion of the Laval nozzle is 0.5, and the control gas flow rate Qs is relative to the flow rate Qm from the main gas injection hole. In Example 3 of the present invention supplied at a ratio of 0.1, the soft blow of the jet is further promoted, the secondary combustion rate during the treatment, and the T.V. The Fe concentration was increased as compared with Example 2 of the present invention, and the dephosphorization rate was further improved. In addition, due to the control gas being led out, the jet flow was further deflected to the furnace wall than in the invention example 2, so that the bare metal adhered in the furnace was also better dissolved.

  In the present invention 4 in which the supply of the control gas is performed only in the first half, the T.V. By promoting the increase of Fe and making hard blow in the second half, the stirring force of top blowing was improved and the dephosphorization rate was greatly improved. Furthermore, by setting the first half of the treatment to soft blow, secondary combustion also increased and ingot dissolution was observed, although not as much as Examples 1-3 of the present invention.

  On the other hand, in Comparative Example 2 in which the first half was soft blown by reducing the acid feed rate, the T.I. Although the dephosphorization rate increased due to the increase of Fe and the improvement of the top blowing stirring force due to hard blow in the latter half, the secondary combustion rate did not increase, and a large amount of metal was attached to the furnace port.

<Second embodiment>
Here, the decarburization behavior at the end of the blow smelting when the decarburization treatment of the molten steel was performed using the 300 ton scale upper bottom blowing converter equipment having the same structure as in FIG. 12 was investigated. During operation, molten steel having a temperature of 1580 to 1600 ° C. and a carbon concentration in the steel of 0.4 to 0.5% was used. Here, since the temperature is high, adhesion of the metal as shown in FIG. 12 does not occur. The operating conditions are as shown in Table 6. Oxygen gas was supplied as an oxidizing gas from the top blowing lance. Nitrogen gas was supplied as the bottom blowing gas.

  Table 7 shows the implementation conditions of the top blowing lance nozzle of the present invention example and the comparative example. A 6-hole Laval nozzle was used as the lance nozzle. In Example 5 of the present invention, as shown in FIG. 11 (the 4 holes are changed to 6 holes), the control gas is connected to all the gas injection holes in the direction connecting the nozzle center point and the center point of each gas injection hole. It was supplied from the outside of the nozzle cross section. The control gas was supplied to all the gas injection holes from the outside in the radial direction of the nozzle. The control gas was supplied from a position where the ratio x / l of the length of the throat portion to the end spread portion of the Laval nozzle was 0.5. The control gas flow rate Qs was supplied at a ratio of 0.1 to the flow rate Qm from the main gas injection hole.

On the other hand, in Comparative Example 3, a normal Laval nozzle that does not supply control gas was used. As shown in Table 7, decarburization treatment was carried out for 5 minutes at a total acid feed rate of 55000 Nm ³ / h and a lance height of 2.3 m, and the final decarburization rate was investigated.

  The results are shown in Table 8. In Example 5 of the present invention in which the control gas is supplied to all the gas injection holes from the outside in the radial direction of the nozzle, the stirring force of the upper blowing jet is increased by combining the jets from the respective nozzles. Compared with Comparative Example 3, the decarburization rate of S is slightly increased.

The schematic diagram which shows the experimental apparatus for confirming the principle of this invention. The schematic diagram which shows the structure of the nozzle used for the principle confirmation investigation. The figure which shows the flow velocity distribution of the jet from each nozzle shown in FIG. FIG. 3 is a flow velocity distribution diagram in the axial direction of a jet flow from each nozzle shown in FIG. 2. The figure which shows the relationship between the deflection angle (beta) of a jet, and working gas ratio Qs / Qm. The figure which shows the relationship between the deflection angle of a jet flow, the main flow, and the difference (Pm-Ps) of control flow introduction side pressure Pm, Ps (kgf / cm < ² >). The figure which compares and shows the deflection angle of the jet at the time of changing a control flow introduction position. Sectional drawing which shows the upper blowing lance which concerns on one Embodiment of this invention. Sectional drawing which shows the upper blowing lance which concerns on other embodiment of this invention. The figure which shows an example of the preferable arrangement | positioning form of the gas supply hole for control in the upper blowing lance which has a some gas injection nozzle. The figure which shows the other example of the preferable arrangement | positioning form of the gas supply hole for control in the upper blowing lance which has a some gas injection nozzle. Schematic which shows the top bottom blowing converter equipment as an implementation equipment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11; Throat part 12; End spreading part 13; Gas injection nozzle 14; Top blowing lance 15,15a, 15b; Control gas supply hole 16; Control gas 17; Jet (jet)
21; Lance nozzle 22; Gas injection nozzle 23; Control gas supply hole

Claims (11)

An upper blowing lance having one or more gas injection nozzles having a throat portion at an inlet portion and a divergent portion downstream of the throat portion, wherein at least one of the gas injection nozzles possess the divergent portion at least one place control gas supply holes and the direction it is intended to deflect the jets disposed on a wall surface opposite to be injected from the gas injection nozzle of the nozzle and the throat portion A ratio x / l between the distance x between the outlet and the center of the control gas supply hole and the distance l between the outlet of the throat portion and the nozzle outlet is 0.3 ≦ x / l <1.0 . An upper blowing lance characterized in that the direction and / or flow velocity of a jet flow ejected from the gas injection nozzle is controlled by supplying a control gas from a gas supply hole. The ratio between the gas flow rate Qs (Nm ³ / min) supplied from the control gas supply hole and the gas flow rate Qm (Nm ³ / min) supplied from the gas injection nozzle is 0.02 ≦ Qs / Qm ≦ 0.3
The top blowing lance according to claim 1 , wherein: A plurality of the gas injection nozzles are provided, and the control gas supply holes are arranged on a straight line connecting the center point of the injection port of each gas injection nozzle and the center point of the lance cross section. The top blowing lance of Claim 1 or Claim 2 . The upper blowing lance according to claim 3 , wherein the control gas supply hole supplies a control gas from the center side of the lance to the gas injection nozzle. The upper blow lance according to claim 3 , wherein the control gas supply hole supplies the control gas to the gas injection nozzle from the outside in the radial direction of the lance. A plurality of the gas injection nozzle, said control gas supply holes, according to claim 1 or claim, characterized in that it is formed from a center side of the lance to provide a control gas to the gas injection nozzle The top blowing lance described in 2 . A plurality of the gas injection nozzle, said control gas supply holes to claim 1 or claim 2, characterized in that it is formed to provide a control gas from the lance outside to the gas injection nozzle Top blown lance as described. A plurality of the gas injection nozzles are provided, and the control gas supply hole selectively supplies control gas to each injection nozzle from the center side of the lance and supply of control gas to each gas injection nozzle from the outside of the lance. The upper blowing lance according to claim 1 or 2 , wherein the upper blowing lance is formed so as to be able to be performed in the same manner. One or more gas injection nozzles having a throat portion at the inlet portion and having a divergent portion downstream of the throat portion are disposed, and at least one of the gas injection nozzles is disposed on the divergent portion of the nozzle. have a controlled gas supply holes of at least one location disposed on the opposite side of the wall the direction to try to deflect the jets injected from the gas injection nozzle, and wherein the control gas from the throat outlet the distance x between the feed hole centers, oxidizing gas using a lance on the ratio x / l and the distance l between the nozzle exit from the throat outlet Ru 0.3 ≦ x / l <1.0 der A converter operation method in which a predetermined operation is performed by supplying a control gas from a control gas supply hole of the gas injection nozzle in a part or all of the processing in the converter. Inject the gas injection nose Converter operation method characterized by controlling the direction and / or flow rate of the jet ejected from. Have a plurality of gas injection nozzle having a diverging portion downstream of having a throat portion and the throat portion to the inlet portion, opposite wall of the direction it is intended to deflect the jets injected from the gas injection nozzle A ratio of a distance x between the control gas supply hole and the center of the control gas supply hole and a distance l between the outlet of the throat part and the nozzle outlet. in converter operation method of supplying x / l is 0.3 ≦ x / l <oxidizing gas using a lance on Ru 1.0 der the rolling furnace, at least one of said gas injection nozzle A method for operating a converter, wherein the oxidizing gas injected from the nozzle is scanned in a direction along a straight line connecting the injection nozzle center point of the gas injection nozzle and the center point of the lance cross section. The oxidizing gas is supplied into the converter using the gas injection nozzle to perform decarburization processing of the molten steel or dephosphorization processing of the molten iron and dissolve the metal attached to the furnace wall of the converter. The converter operating method according to claim 9 or 10 , wherein:

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