KR20040058552A - Bottom Blowing Equipment For Furnance - Google Patents

Abstract

PURPOSE: An apparatus for bottom-blowing in converter is provided to increase bubbling in steel bath by blowing high pressure nitrogen downward in an upper blowing converter and improve reaction in the furnace by promoting decarburization reaction during blowing. CONSTITUTION: The apparatus comprises a plurality of thin tube bundle type nozzles(7) installed on a lower part of the converter with being spaced apart from each other in a certain distance in such a way that the nozzles are directed to the inside of the converter; a controller(8) for controlling type, pressure and flow rate of bottom blowing gas supplied from the lower part of the converter through the plurality of thin tube bundle type nozzles according to type of molten steel poured into the converter; a compressor part(2) comprising one or more of nitrogen compressors(21,22) installed on nitrogen gas line to produce high pressure nitrogen gas, an extra compressor(23) connected to nitrogen line and argon line respectively through switch valve to replace function of compressor broken down, and an argon gas compressor(24) installed on the argon gas line to produce high pressure argon gas; first and second gas holders(31,32) for respectively storing nitrogen and argon of high pressure produced from the compressor part; pneumatic control valves(41,44) respectively installed on gas pipes connected to a discharge side of the first and second gas holders to primarily control pressure of the high pressure nitrogen and argon gases according to control of the controller; pressure control valves(42,45) and cutout valves(43,46) installed on gas pipes connected to a rear part of the pneumatic control valves to finely control pressure of the primarily pressure controlled nitrogen and argon gases; a header(5) into which the nitrogen and argon gases supplied through the pressure control valves and the cutout valves are mixed and collected; a bottom blowing gas supply pipe for transferring a mixed gas collected into the header to the plurality of thin tube bundle type nozzles; flow rate measuring instruments(61,62) installed on the bottom blowing gas supply pipe to measure flow rate of the mixed gas applied to the plurality of thin tube bundle type nozzles; flow rate control valves(47,48) for controlling flow rate of gas applied to the plurality of nozzles by receiving control of the controller; and pressure meters(63,64) for measuring pressure of high pressure gas applied to the plurality of nozzles.

Description

Bottom Blowing Equipment For Furnance

The present invention relates to a converter facility for oxidizing impurities in the molten iron in the steelmaking process to refine the molten steel, more specifically, by increasing the agitation power of the molten steel by the low odor gas in the furnace of the combined-melting method by promoting the decarburization reaction in the furnace It relates to a low odor gas blowing device of the converter improved.

In general, pig iron from the iron making process has a high carbon content and contains a considerable amount of impurities such as phosphorus (P), sulfur (S), and silicon (Si), and thus has high hardness and brittleness. Therefore, in order to make the iron of this property well stretched into a tough steel, it must be refined again to reduce the amount of carbon (C) and to remove harmful impurities. This treatment of pig iron is performed in the steelmaking process.

As a typical facility of the said steelmaking process, a converter and an electric furnace are mentioned.

Among them, the converter is in the form of a jar, charged with molten iron and a small amount of scrap iron and calcite, and then blows high-purity oxygen gas at a high pressure from the top to oxidize and burn carbon and impurities contained in pig iron. It is a facility to slag oxide and remove it.

This converter operation method is divided into low squirt converter with strong agitation power, such as a slope suppressing effect, and a top squirt converter, which is advantageous for delineation reaction. In the case of the former squirrel converter, the mixing power is long due to the lack of agitation power. It has the drawback that the total Fe content is high. In the latter case, the decarburization reaction in the low carbon region depends only on the agitation of the bath by the energy of the oxygen jet, and thus the agitation power is insufficient, so that the active ingredients of iron (Fe) and manganese (Mn) Oxidation loss increases, slag temperature is higher than the bath temperature, which is disadvantageous to the Tallinn reaction, and the components and temperature in the bath are nonuniform.

In order to make up for these drawbacks, a combination of the two methods has been developed, but the low oil flow rate is very low, and the gas switching during the low odor operation is not practical.

The present invention has been proposed in order to solve the above-mentioned conventional problems, and its object is to blow high pressure nitrogen from the upper blast furnace to the bottom to increase the agitation power of the molten steel and promote the decarburization reaction during the blowing to perform the furnace reaction. It is to provide an improved low odor gas blowing device.

Another object of the present invention is to automatically control to blow the low odor gas used in the molten steel stirring in the low filtration industry in a predetermined pattern according to the steel type in the compound blow, the low odor of the converter in the converter facility of the combined blow method of improving the stirring power of the molten steel It is to provide a gas blowing device.

BRIEF DESCRIPTION OF THE DRAWINGS It is the whole block diagram of the low odor gas blowing apparatus of the converter which concerns on this invention.

2 is a configuration diagram of a low odor nozzle according to the present invention.

(A) is sectional drawing of the low odor nozzle applied to the low odor gas blowing apparatus of the converter by this invention, (b) is a side view, (c) is a top view.

4 (a) to 4 (c) are schematic diagrams showing a state in which a flow rate bias occurs in a low odor nozzle.

5 is a control system structure diagram of a low odor gas injection device of a converter according to the present invention.

6A and 6B show an example of a low odor pattern table formed in a low odor gas injection device of a converter according to the present invention.

Explanation of symbols on the main parts of the drawings

1: converter 7, 71 ~ 78: tubular bundle type nozzle

8 controller 21, 22 nitrogen compressor

23: preliminary compressor 24: argon gas compressor

31, 32: first and second gas holder 41, 44: pneumatic control valve

42, 45: pressure regulating valve 43, 46: shutoff valve

5: header 6, 6a, 6b: low odor gas supply pipe

61, 62: flow meter 47, 48: flow control valve

63, 64: Pressure gauge

As a means for achieving the above object of the present invention, the present invention is a low odor gas blowing device of the converter,

A plurality of tubular nozzles installed in the lower part of the converter so that the nozzles face the inside of the converter at a predetermined interval;

A controller for controlling the gas type, pressure and flow rate of the low odor gas to be supplied from the lower portion of the converter through the plurality of tubular nozzles according to the steel grade of the molten steel that has entered the converter;

At least one nitrogen compressor installed in the nitrogen gas line to produce high pressure nitrogen gas, a spare compressor connected to the nitrogen line and the argon line through an on-off valve to replace the function of the failed compressor, and the argon gas line. A compressor unit which is installed and comprises an argon gas compressor for producing high pressure argon gas;

First and second gas holders for storing high-pressure nitrogen and argon produced from the compressor unit, respectively;

A pneumatic control valve installed at each of the gas pipes connected to the discharge side of the first and second gas holders to adjust pressure of nitrogen and argon gas of high pressure according to the control of the controller;

A pressure regulating valve and a shutoff valve installed at a gas pipe connected to a rear end of the pneumatic control valve to finely adjust the pressure of nitrogen and argon gas, respectively, of which primary pressure is controlled;

A header in which nitrogen gas and argon gas are mixed and provided through the pressure control valve and the shutoff valve;

A low odor gas supply pipe for delivering the mixed gas collected in the header to a plurality of capillary valve nozzles;

A flow rate meter installed in the low odor gas supply pipe and measuring a flow rate of the mixed gas applied to the plurality of tubular nozzles;

A flow rate control valve controlling a gas flow rate applied to the plurality of nozzles under the control of the controller; And

It characterized in that it comprises a pressure gauge for measuring the pressure of the high-pressure gas applied to the tubular bundle type nozzle.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the low-gas injection device of the converter according to the present invention.

Figure 1 shows a low blowing gas blowing device according to the present invention, in the converter (1) in which oxygen is blown through the oxygen lance 12 from the top, the apparatus according to the present invention is the lower part of the converter (1) A plurality of tubular bundle nozzles 7 installed so that the nozzles are directed toward the inside of the converter at regular intervals, and through the plurality of tubular nozzles 7 according to the steel grades of the molten steel that have entered the converter 1. The controller 8 for setting the pressure and flow rate of the low odor gas to be supplied from the lower part of 1), the nitrogen line through the on-off valve and the nitrogen compressor (21, 22) installed in the nitrogen gas line to produce high-pressure nitrogen gas And a compressor unit (2) consisting of an argon gas compressor (24), which is connected to an argon line to replace a function of a failed compressor, and an argon gas compressor (24) installed in the argon gas line to produce high-pressure argon gas. remind First and second gas holders 31 and 32 for storing high-pressure nitrogen and argon produced from the pressing unit 2, and gas pipes connected to the discharge sides of the first and second gas holders 31 and 32, respectively. Pneumatic control valves 41 and 44 for adjusting pressure of nitrogen and argon gas of high pressure respectively according to the control of the controller 8 and gas pipes connected to the rear ends of the pneumatic control valves 41 and 44, respectively. Pressure control valves 42 and 45 and shutoff valves 43 and 46 for fine-adjusting the pressure of primary pressure-regulated nitrogen and argon gas, respectively, and the pressure control valves 42 and 45 and shutoff valves 43 and 46, respectively. A header (5) in which nitrogen gas and argon gas provided through the mixture are collected and collected, a low odor gas supply pipe (6) for delivering the mixed gas collected in the header (5) to a plurality of capillary valve nozzles (7), and Flow rate which measures the flow volume of the mixed gas which is installed in the low odor gas supply pipe 6, and is applied to many tubular bundle type nozzles 7 And the flow control valves 47 and 48 for controlling the gas flows applied to the plurality of nozzles 7 under the control of the controllers 8 and 8 and the tubular bundle nozzles 7. It consists of pressure gauges 63 and 64 for measuring the pressure of the high pressure gas.

FIG. 2 is a bottom section of the converter showing the arrangement structure of the lower part of the converter with respect to the low odor nozzle 7 for blowing the low odor gas in the apparatus, in which 14 represents the shell of the converter and 15 is the shell 14 Refractories protecting the shell 14 from high temperature molten steel are shown, and 71 to 74 represent low odor nozzles formed at the bottom of the converter.

Although not shown in the figure, the bottom of the converter 1 has a curved shape. Accordingly, the low odor nozzles 71 to 74 are arranged at regular intervals with respect to the central portion of the bottom of the converter 1 and are installed at an injection angle of 13 degrees. Thus, the spacing between the nozzles is wider at the iron skin than at the internal refractory surface.

The arrangement of the low odor nozzle 7 as described above greatly affects the stirring force. In this case, consideration should be given to the arrangement of the low odor nozzle. First, it is necessary to avoid the flash point by the upper lance 12, and second, to avoid affecting the temperature measurement and sampling by the sub lance. Fifth, fourth, the slag line should be out of the slope at the time of tapping, while maintaining a gap such that the erosion of a single nozzle will not affect the surrounding other nozzles.

As an arrangement that satisfies these conditions, the present invention arranges four nozzles at a 13 degree angle in a rectangular shape of a size of 1874 to 2228 x 700 to 852 [mm], as shown in FIG. As a result of the flow observation of the molten steel, it is determined as the most preferable position satisfying the above condition.

In addition, the nozzles 7 installed in the lower portion of the converter 1 are tubular bundle nozzles composed of a plurality of small nozzles as shown in FIGS. 3 (a) to 3 (c).

More specifically, each of the nozzles 7 is a bundle of 37 tubules 7a having an inner diameter of 2 mm at regular intervals and bundled into bundles. The cross-sectional area of each tubule is 1,162 cm 3 and the linear velocity is 55.302 m. / sec and the material is made of SUS304.

The total number of nozzles 7 thus constructed consists of four per converter.

In order to maximize the agitation action of the bath in the inside of the converter by using the low odor gas injection device of the converter configured as described above, the low odor flow rate supplied to the low odor nozzle (7) in consideration of the converter thallon to ensure sufficient agitation flow rate (For example, 18500 Nm 3 / Hr) is set on the basis of 5% (about 15Nm 3 / Hr), so that the set amount is suitable for high-carbon steel production, as shown in FIG. Blown through 7).

In particular, as shown in Fig. 3 (a), the low-nozzle nozzle 7 has the nozzles 71 to 74 having 37 multiple hole plugs (MHPs) as shown in Fig. When virtually creating a rectangle of a predetermined size with respect to the center of the nion axis, by arranging at the vertex of the rectangle, it is possible to maintain the balance of the erosion of the bottom portion and to secure sufficient stirring force.

In addition, four spare nozzles 75 to 78 on the same diagonal axis can be replaced when one of the plurality of tubular nozzles 71 to 74 cannot be used normally due to being blocked or damaged. It may be further provided.

In addition, the apparatus according to the present invention was applied to converter equipment, and the uniform mixing time was measured by the water model test. As a result, the low odor gas supplied to the low odor nozzle 7 has a relatively high flow rate. As a result of observing the flow of molten steel inside the converter 1, as shown in FIG. 2, the arrangement of four nozzles in the seven rows of the rectangular section of the bottom of the furnace to minimize the erosion of the furnace wall In addition, it was judged that arrangement | positioning in the same row was the most preferable also with a nozzle.

And, most of the melting loss of the low odor nozzle 7 is caused by melting of the pipe due to intrusion of molten iron into the nozzle capillary 7a, the surrounding refractory mechanically worn by the high-pressure gas, or eroded by the back pressure. It is estimated that the process of repetition occurs, and if such low-nozzle nozzles become severely invaded, the intrusion of molten iron is further accelerated to infiltrate deeply into the inside of the tubular pipe 7a, and the infiltrated molten iron is changed to the change of ambient temperature. In the case of solidification, clogging occurs.

In the present invention, the spare nozzles 75 to 78 are further installed to replace the clogged nozzles, and when clogged nozzles are generated, low blowing gas blowing is performed instead of the corresponding spare nozzles 75 to 78.

As described above, the following Table 1 collectively shows the conditions for the optimum low odorizing operation in the low odor gas injection device of the converter according to the present invention.

Item In design Remarks Converter capacity 100 ton / heat Low odor flow rate 15 N㎥ / min Nozzle type and number 4 nozzles for customs tubing: 2mm inner diameter × 37 Four identical nozzles Nozzle Arrangement Seven rows of rectangular 1874 × 700 [mm] converter trunnion shafts Place at each vertex of the rectangle Distance between nozzles 700 [mm] Nozzle / No-Wall Distance 1,058 [mm] Size of the tubular nozzle Refractory Overall 999 [mm] Built-in Length 740 [mm] Refractory material MgO-Graphite

In addition, the present invention supplies nitrogen and argon mixed gas to the four tubular bundle nozzles 7 configured as described above through two pipes 6a and 6b connected through the drive unit and the non-drive unit of the converter.

The two supply pipes (6a, 6b) are installed using the space between the trunnion and the shell for the rotation of the converter (1).

Figure 5 shows a control structure for controlling the low odor gas injection device of the converter according to the present invention, the upper controller 9 is calculated by the mathematical model for low odor operation as shown in Figure 6a and 6b Set the low odor pattern for determining the gas type and flow rate for each blowing section according to, and transmits it to the controller 8 of the plurality of converters, and manages the low odor performance for each converter.

Then, the controller 8 calculates the type of gas and the flow rate to be supplied based on the low odor pattern table provided from the upper controller 9, and accordingly controls the low odor operation of the converter 1, The operation status of the low odor manufacturing equipment is displayed on the screen.

At this time, the controller 8 is a monitoring screen for comprehensively monitoring the low odor operation state, the low odor operation state of each converter, the open / closed state of the low odor gas control valves 41 to 48 shown in FIG. The operating / failure state of the compressors 21 to 24 and the temperature, pressure and flow rate of nitrogen and argon gas measured from various measuring instruments are displayed.

In addition, the controller 8 is a screen for notifying the low blowing pattern, and displays the full and non-collecting section full text received from the upper controller 9, and determines whether the received full text is suitable, the blowing section is 10 In the step, the pattern is displayed as ten per converter. The step of the blowing section can be changed according to the amount of intake oxygen. The low odor pattern can be inputted from the set 1 to 10 and cannot be selected during drilling, and displays the low odor design determination data according to the selected pattern number. The data for each step can also be changed. However, it is possible only for unscheduled steps during the drilling.

From the above installation conditions, the control process for optimum low odor effect is performed as follows.

As shown in FIG. 1, the low blowing gas blowing device of the converter is provided with four compressors 21 to 24 to supply stable gas when blowing the low blowing gas, and each of the four compressors is for operating nitrogen gas. Two compressors (21,22) of 700 Nm3 / hr, one compressor (24) of 400 Nm3 / hr for argon gas operation, and 700 Nm3 / hr common to nitrogen and argon gas for reserve. Compressor consists of one 23.

The compressors 21 to 24 respectively suck nitrogen (N ₂ ) and argon (Ar) gas at a suction pressure of 3 to 7 Kg / cm 3, and respectively, the nitrogen gas holder 31 and the argon gas holder (30 at a pressure of 30 Kg / cm 3). 32).

Then, the operation of the compressors 21 to 24 is operated by automatically unloading at 26 Kg / cm 3 under the feedback of the pressures of the holders 31 and 32, and automatically reserves when an abnormality occurs in a predetermined compressor during operation. Switching to the compressor 23 is made.

The preliminary compressor 23 is provided with valves 25 to 26 that are selectively connected to the nitrogen line and the argon line to continuously operate with the same gas according to the gas type of the compressor in which the abnormality occurs, and the valve 25 Gas switching is performed by the opening and closing of ˜26).

On the discharge side of the gas holders 31 and 32, the pressure of the gas discharged from the gas holders 31 and 32 by the pressure control valves 42 and 45 is lowered from 30 kg / cm 3 to 13 kg / cm 3 and lowered. Pressure is measured and monitored through pressure gauges (63, 64). Then, the flow rate is controlled by measuring the flow rate of the gas actually flowing through the flow rate measuring instruments 61 and 62 and adjusting the opening degree of the flow rate control valves 47 and 48.

At this time, the flow rate control is carried out in common to the nitrogen gas and argon gas, the specific gravity that is different for each gas is corrected by the controller (8). For example, when nitrogen gas is 1, argon gas is corrected to 1.4.

The setting and monitoring of the flow rate and pressure as described above is configured by the controller 8 to be performed by the driver on the MMI (Man Maching Interface) screen. To be monitored as an integration.

Accordingly, the low odor operation controls the control valves 42 to 48 located in the lower part of the converter automatically during one cycle of exclusion from the charter loading and waiting for the next charge based on the operation data set in advance in the controller 8. And flow rate and pressure control, nitrogen and argon gas are applied to the head 5 through the valves 42 to 48 controlled as described above, and then supplied from the head portion 5 through the driving portion and the non-driving portion. It is applied to the four tubular nozzles 7 through two pipes.

Therefore, nitrogen and argon gas of high pressure are blown in from the lower part of the converter 1 through the said tubular bundle nozzle 7.

Table 2 below shows the measurement results of the intermediate operation applying the stirring device according to the present invention.

division Nosing converter (No. 1, 2) A Compound Blower Difference (B-A) Good breathability (B) Poor breathability End point [C] [O] 0.0037 0.002 0.0028 End point [O] f, ppm 778 748 764 -30 Slag T.Fe,% 23.6 21.9 22.4 -1.7 Terminal component% P 0.019 0.014 0.0015 -0.005 Mn 0.06 0.1 0.09 0.04 Total delivery quantity Nm3 / heat 5,380 5,080 5,110 -300

Referring to Table 2, in the case of the composite blow according to the present invention, the end point [C] [O] value is lower than in the case of the top converter, the oxidation degree in the same [C] region is reduced and T. It can be seen that Fe decreases. In addition, the dephosphorylation effect was also improved by increasing the performance Lp (serving ratio) value compared to the above-mentioned converter method when using the same amount of sub-raw materials. In view of this, the present invention can reduce the amount of quicklime input, it can be seen that the ability to control the composition at high temperatures during blowing on the general molten iron.

As described above, the lower odor gas can be effectively introduced into the converter through the lower part of the converter, and as a result, the agitation power of the molten steel in the converter can be increased and as a result, the decarburization reaction can be promoted to improve productivity. have. In addition, when viewed based on the same amount of production, there is an excellent effect that can reduce the input amount of the raw material compared to the conventional.

Claims (4)

In converter facility of compound blow type, A plurality of tubular bundle nozzles (7) installed in the lower part of the converter so that the nozzles are directed into the converter at a predetermined interval; A controller (8) for controlling the gas type, pressure and flow rate of the low odor gas to be supplied from the lower portion of the converter through the plurality of tubular nozzles (7) according to the steel type of the molten steel that has entered the converter; One or more nitrogen compressors 21 and 22 installed in the nitrogen gas line to produce high pressure nitrogen gas, and spare compressors that are connected to the nitrogen line and the argon line through open / close valves, respectively, to replace the function of the failed compressor. 23) and a compressor unit 2 formed of an argon gas compressor 24 installed in the argon gas line to produce high pressure argon gas; First and second gas holders 31 and 32 for storing high-pressure nitrogen and argon, respectively, produced from the compressor unit 2; Pneumatic control valves 41 and 44 which are respectively installed in the gas pipes connected to the discharge sides of the first and second gas holders 31 and 32 to adjust pressure of nitrogen and argon gas of high pressure according to the control of the controller 8. )Wow, Pressure control valves 42 and 45 and shutoff valves 43 and 46 installed in the gas pipe connected to the rear ends of the pneumatic control valves 41 and 44 to finely adjust the pressures of the primary pressure-regulated nitrogen and argon gas, respectively. ; A header 5 in which nitrogen gas and argon gas provided through the pressure control valves 42 and 45 and the shutoff valves 43 and 46 are collected and mixed; A low odor gas supply pipe (6) for delivering the mixed gas collected in the header (5) to the plurality of capillary valve nozzles (7); Flow rate measuring instruments (61, 62) installed in the low odor gas supply pipe (6) for measuring the flow rate of the mixed gas applied to the plurality of tubular bundle nozzle (7); Flow control valves 47 and 48 for controlling the gas flow rate applied to the plurality of nozzles 7 under the control of the controller 8; And Pressure measuring devices (63, 64) for measuring the pressure of the high pressure gas applied to the tubular bundle nozzle (7) Low-odor gas injection device of the converter characterized in that consisting of. The method of claim 1, wherein the plurality of tubular nozzles 7 A four-tubular bundle nozzle (71 to 74) installed at a corner of a rectangle with respect to the center of the center of the Roger trunnion axis of the converter (1) so as to have a spray angle of 13 degrees toward the center of the converter (1). Low gas blowing device. 3. A plurality of tubular nozzles (7) according to claim 2, wherein Low-gas injection device of the converter characterized in that it further comprises four preliminary tubular bundle nozzles (75 ~ 78) installed in a similar position so as to correspond to the four tubular bundle bunching nozzles (71 ~ 74). According to claim 1, wherein the low-odor gas supply pipe (6) It is installed by using the space between the trunnion and the iron shell for the rotation of the converter, characterized in that consisting of two pipes (6a, 6b) simultaneously connected to the plurality of tubular bundle nozzle (7) through the drive unit and the non-drive unit of the converter Low odor gas blowing device of converter.