JP2010159444A - Apparatus for preventing backflow in metallurgical lance having burner function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a backflow of a gas for a burner, when blockage has occurred in a metallurgical lance which has the burner on the tip and charges ore into a furnace by passing the ore through a flame formed by the burner, by quickly detecting the blockage. <P>SOLUTION: The apparatus for preventing the backflow in the metallurgical lance which has an ore flow tube 9 for supplying the ore provided in its central part and flow channels for fuel and oxygen gas independently provided in the periphery of the ore flow tube has blocking valves 13 and 14 and pressure gauges 15 and 16 provided on a fuel supply pipe 10 and an oxygen gas supply pipe 11, respectively, and a control device 17 which receives pressure values measured by these two pressure gauges and sends a total closure signal to the two blocking valves based on the input measured pressure values. When the pressure value measured by any one of the two pressure gauges has exceeded a previously set threshold, the two blocking valves automatically close the flow channels according to the total closure signal sent from the control device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a backflow prevention device in a metallurgical lance that has a burner function at its tip and passes ore such as chromium ore through a flame formed by the burner function and is charged into a metallurgical furnace. The present invention relates to a backflow prevention device for preventing a backflow of burner gas generated due to blockage at the lance tip caused by adhesion of a metal base to the lance tip.

  When melting steel material, instead of expensive alloy iron, cheap ore (for example, chromium ore) is charged together with carbonaceous materials (for example, coke) into an iron bath type smelting reduction furnace such as a converter. A technique for melting a molten metal containing a valuable metal (for example, chromium) by melting and reducing the inside of a furnace has been performed. This technique is called a smelting reduction method. In the smelting reduction method, a granular ore with a small particle size is used. In order to recover valuable metals in the ore as a molten metal, a metal oxide or Since the reduction reaction of oxide-based ore is an endothermic reaction, a large amount of thermal energy is required to cause the reduction reaction.

As a heat source in this smelting reduction method, conventionally, heat energy obtained by burning (referred to as “primary combustion”) a carbon material charged in the furnace by supplying oxygen gas (O ₂ ) into the furnace, Further, thermal energy obtained by further burning (referred to as “secondary combustion”) of carbon monoxide (CO) generated by the primary combustion to generate carbon dioxide (CO ₂ ) has been used.

  However, increasing the charging amount of ore, which is an inexpensive raw material, in order to reduce the melting cost of molten metal containing valuable metals requires a large amount of thermal energy, so it is necessary to promote primary combustion and secondary combustion. is there. However, if the oxygen gas flow rate is increased in order to promote these, the amount of dust generated increases and the yield of valuable metals decreases, so there is a limit even if primary combustion and secondary combustion are promoted.

  Therefore, in Patent Document 1, an ore charging lance for charging granular ore into a furnace is installed separately from an upper blowing lance for supplying an oxidizing gas, and an ore flow hole is provided at the tip of the ore charging lance. And a burner consisting of injection holes (nozzles) for blowing fuel and oxygen gas, a flame is generated by the burner, the ore is heated by passing through the flame, and the heated ore is added. Has proposed a technique to increase the amount of heat applied to the molten metal in the furnace, thereby increasing the amount of ore charged.

  With this technology, the amount of heat received by the molten metal in the furnace increased, but during the smelting reduction, a new problem occurred in which the ore charging lance was clogged due to adhesion of metal to the tip of the ore charging lance. When the ore charging lance is blocked, the supplied fuel and oxygen gas flow backward, and the fuel and oxygen gas flowing backward burn in the flow path of the ore charging lance or the supply pipe, resulting in damage to equipment. Also, the supplied fuel and oxygen gas flow back through the ore distribution pipe of the ore input lance through the ore distribution hole at the tip, and leak, for example, from an ore containing hopper installed in the upper part of the ore distribution pipe. The problem of doing will also occur. With respect to this problem, Patent Document 1 does not take any measures.

  Conventionally, as a countermeasure for preventing a backflow in piping, a check valve is generally provided in the supply piping. However, the gas supply itself does not stop with the check valve alone, and if the gas supply side pressure becomes higher than the lance side pressure, the check valve opens and the gas is supplied again to the lance side, causing ignition, etc. There is a risk of trouble recurrence. That is, the installation of only the check valve cannot be a countermeasure for the above problem.

  On the other hand, in Patent Document 2, when removing the deposits on the refining lance, after the refining is finished, while moving the lance to the standby position, oxygen gas is injected onto the outer surface of the lance to dissolve and remove the deposits. At the same time, a technique has been proposed in which a deposit release agent is sprayed on the outer surface to form a deposit release coating. However, in the case of a lance having a burner function at the tip portion, the tip portion structure is complicated, and the metal is attached so as to enter the complicated portion, and oxygen gas is injected to the outer surface of the lance. It is difficult to dissolve the adherent metal alone.

JP 2007-138207 A JP 11-279619 A

  The present invention has been made in view of the above circumstances, and the object thereof is to have a burner function at the tip thereof, and to pass a metal ore such as chromium ore through a flame formed by the burner function. When smelting or refining using a metallurgical lance inserted into the lance, if a blockage occurs at the lance tip opening due to adhesion of metal to the tip of the lance, this blockage is prevented. It is possible to quickly detect and prevent the backflow of the gas for the burner, and furthermore, the backflow of the metallurgical lance having a burner function that can also prevent the backflow to the ore distribution pipe provided in the metallurgical lance. It is to provide a backflow prevention device.

  An apparatus for preventing backflow of a metallurgical lance having a burner function according to a first aspect of the present invention for solving the above problems is provided with an ore distribution pipe for supplying ore to the center, and a fuel around the ore distribution pipe And a backflow prevention device for a metallurgical lance having a burner function, in which an oxygen gas flow path is provided independently, and a fuel supply pipe for supplying the fuel and an oxygen gas for supplying the oxygen gas Each supply pipe is provided with a shut-off valve and a pressure gauge, pressure measurement values from these two pressure gauges are input, and a full-close signal is transmitted to the two shut-off valves based on the input pressure measurement values. When the pressure measurement value by one of the two pressure gauges exceeds a preset threshold value, the two shutoff valves are automatically turned on by a fully closed signal from the control device. And it is characterized in that it is configured to close the.

  According to a second aspect of the present invention, there is provided a metallurgy lance backflow prevention device having a burner function, wherein an ore circulation pipe for supplying ore is provided at a central portion, and fuel and oxygen gas flow paths are provided around the ore circulation pipe. A backflow prevention device for a metallurgical lance having a burner function, which is provided independently, and shuts off the fuel supply pipe for supplying the fuel and the oxygen gas supply pipe for supplying the oxygen gas, respectively. In addition to providing a valve and a pressure gauge, a gas detection means is provided in the upper part or inlet of the ore circulation pipe, and a pressure measurement value by the two pressure gauges and a gas composition value detected by the gas detection means are input. And a control device for transmitting a fully closed signal to the two shut-off valves based on the input pressure measurement value and gas composition value, and the pressure measurement value by one of the two pressure gauges is previously When the set threshold value is exceeded or when the gas composition value detected by the gas detection means exceeds a preset threshold value, the two shut-off valves are automatically activated by a fully closed signal from the control device. It is configured to close the flow path.

  According to a third aspect of the present invention, in the first or second invention, the control device transmits a full-close signal to the two shut-off valves, or the Before and after, a signal is sent to the ore supply means for controlling the supply rate of the ore supplied from the ore distribution pipe so as to reduce the supply rate to a preset value, whereby the ore is supplied to the metallurgical furnace. It is characterized in that the supply speed is automatically reduced.

  According to the present invention, the blockage of the fuel flow path and the oxygen gas flow path in the metallurgical lance having a burner function is detected by the pressure increase in the pressure gauge installed in each supply pipe, and immediately after the blockage is detected. Since the supply of fuel and oxygen gas is stopped, troubles caused by the backflow of fuel and oxygen gas can be prevented in advance. Furthermore, when the gas detection means is provided in the upper part or the inlet part of the ore circulation pipe, it is possible to detect the fuel or oxygen gas that flows backward by the gas detection means, thus preventing backflow to the ore circulation pipe. It becomes possible.

It is a figure which shows the 1st example of this invention, and is the schematic of the smelting reduction equipment of a chromium ore provided with the backflow prevention apparatus of the metallurgical lance which concerns on this invention. It is a figure which shows the 2nd example of this invention, and is the schematic of the smelting reduction equipment of a chromium ore provided with the backflow prevention apparatus of the metallurgical lance which concerns on this invention.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. First, a first embodiment of the present invention will be described. FIG. 1 is a diagram showing a first embodiment of the present invention, and is a schematic diagram of a chrome ore smelting reduction facility equipped with a backflow prevention device for a metallurgical lance according to the present invention.

  As shown in FIG. 1, an iron bath smelting reduction furnace facility 1 that melts and reduces chromium ore to melt chromium-containing molten metal 6 performs a chromium ore melting and reducing reaction, A furnace body 2 to be stored, an upper blowing lance 3 which is installed at substantially the center of the furnace body 2 and which can raise and lower the interior of the furnace body 2, which blows an oxidizing gas into the furnace body 2, An ore charging lance 4, which is installed at a position away from the axis of the main body 2, can supply chrome ore into the furnace main body 2, can move up and down in the furnace main body 2, and is defined as a metallurgical lance in the present invention; It is equipped with.

  The bottom of the furnace body 2 is provided with a plurality of bottom blowing tuyere 5 for blowing nitrogen gas, Ar gas, or the like into the furnace body 2 as a stirring gas. It is connected to an oxidizing gas supply pipe 8 that supplies an oxidizing gas such as oxygen-enriched air, and the oxidizing gas supplied through the oxidizing gas supply pipe 8 is blown into the inside of the furnace body 2 from its tip. It has become.

  On the other hand, a fuel supply pipe 10 and an oxygen gas supply pipe 11 are connected to the ore charging lance 4, and an ore distribution pipe 9 for passing chromium ore is installed at the center of the ore charging lance 4. Around the ore circulation pipe 9, a fuel flow path (not shown) for passing the fuel supplied from the fuel supply pipe 10 and an oxygen gas flow path for passing the oxygen gas supplied from the oxygen gas supply pipe 11. (Not shown) are arranged independently of each other. As the fuel, gaseous fuel such as methane gas, propane gas and coke oven gas, and liquid fuel such as light oil and heavy oil can be used. Here, an example using gaseous fuel will be described.

  The fuel supplied through the fuel flow path provided in the ore charging lance 4 and the oxygen gas supplied through the oxygen gas flow path provided in the ore charging lance 4 are the tip of the ore charging lance 4. Are mixed with each other and burned to form a flame 26 at the tip of the ore charging lance 4. In this case, the ore charging lance 4 has a circular ore circulation hole (not shown) formed by opening the ore circulation pipe 9 and an oxygen gas channel opening from the center to the outer periphery. The annular oxygen gas nozzle (not shown) formed in this manner and the annular fuel nozzle (not shown) formed by opening the fuel flow path are concentrically arranged. Yes. Further, if necessary, it is possible to further provide a cooling water supply / drainage channel on the outer periphery of the fuel channel. That is, the ore charging lance 4 is composed of concentric multiple tubes.

  The upper end portion of the ore distribution pipe 9 is connected to the ore containing hopper 20, and the chromium ore supplied to the ore containing hopper 20 by the ore supply conveyor 22 falls freely inside the ore distribution pipe 9, and the ore It reaches the lower end of the charging lance 4 and is charged into the furnace body 2 while being heated by the formed flame 26. As described above, the ore containing hopper 20, the ore supply conveyor 22 and the electric motor 23 constitute an ore supply means. The ore supply conveyor 22 is driven by an electric motor 23, and the supply speed of the chromium ore to the ore containing hopper 20 is adjusted by controlling the rotation speed of the electric motor 23. In the figure, reference numeral 25 denotes a chrome ore falling in the flame 26 while being heated by the flame 26.

  The fuel supply pipe 10 and the oxygen gas supply pipe 11 are provided with a fuel cutoff valve 13 and a fuel pressure gauge 15, an oxygen gas cutoff valve 14 and an oxygen gas pressure gauge 16, respectively, at each valve stand 12. . Further, the fuel supply pipe 10 is provided with a fuel bleed valve 18 for opening the fuel supply pipe 10 to the downstream side of the fuel cutoff valve 13. Similarly, the oxygen gas supply pipe 11 has an oxygen gas cutoff. An oxygen gas bleed valve 19 for opening the oxygen gas supply pipe 11 to the atmosphere is provided downstream of the valve 14. The pressure measurement value by the fuel pressure gauge 15 and the pressure measurement value by the oxygen gas pressure gauge 16 are input to the control device 17.

  The operation of the fuel cutoff valve 13, the oxygen gas cutoff valve 14, the fuel bleed valve 18, the oxygen gas bleed valve 19 and the electric motor 23 is controlled by the control device 17. That is, the fuel shutoff valve 13 and the oxygen gas shutoff valve 14 are forcibly closed by the “fully closed signal” transmitted by the control device 17, and the fuel bleed valve 18 and the oxygen gas bleed valve 19 are controlled. The flow path is forcibly opened by a “full open signal” transmitted by the device 17, and the electric motor 23 is configured to be changed to a preset rotation speed by a signal transmitted by the control device 17. .

  That is, the control device 17 closes the fuel cutoff valve 13 and the oxygen gas cutoff valve 14 on the basis of the pressure measurement values input from the fuel pressure gauge 15 and the oxygen gas pressure gauge 16, as well as the fuel bleed valve 18 and the oxygen gas bleed. The valve 19 is opened, and further, the rotational speed of the electric motor 23 is changed in order to change the supply rate of the chromium ore to the furnace body 2. In this case, a threshold value (upper limit value) is set in advance for the pressure of the fuel supply pipe 10 and the oxygen gas supply pipe 11, and when the measured pressure value exceeds the threshold value, the fuel nozzle at the tip of the ore charging lance 4 Alternatively, it is configured that the above signals are transmitted to the respective devices when the oxygen gas nozzle is clogged, that is, when the clogging is detected.

  In the iron bath type smelting reduction furnace equipment 1 configured as described above, the stirring gas is blown from the bottom blowing tuyere 5 to stir the molten metal 6, and the oxidizing gas 24 such as oxygen gas from the top blowing lance 3. Is injected into the furnace body 2 through the ore charging lance 4 having the flame 26 formed at the tip thereof, and the carbonaceous material such as coke separately charged into the furnace body 2. The chrome ore 25 is melted by the heat of combustion and the heat of the flame 26 to form a molten slag 7, and the molten slag 7 is reduced with a carbon material to melt the molten metal 6 containing chromium. When the molten metal 6 or the molten slag 7 scatters and adheres to the tip of the ore charging lance 4 during the melting, and the fuel nozzle or the oxygen gas nozzle is blocked, the fuel pressure depends on the blocked nozzle. The pressure in either meter 15 or oxygen manometer 16 increases.

  The measurement values of the fuel pressure gauge 15 and the oxygen pressure gauge 16 are transmitted to the control device 17, and the control device 17 compares the pressure threshold value set in advance with the pressure measurement value, and the pressure measurement value exceeds the threshold value. In this case, it is determined that a blockage has occurred, the fuel cutoff valve 13 and the oxygen gas cutoff valve 14 are closed, the fuel bleed valve 18 and the oxygen gas bleed valve 19 are opened, and the number of revolutions of the electric motor 23 is set in advance. The number of revolutions is changed to a lower number than in the normal state.

  The reason why the rotational speed of the electric motor 23 is changed to a rotational speed lower than that in the normal state is that the amount of heat supplied to the furnace body 2 is reduced by extinguishing the flame 26 at the tip of the ore charging lance 4. This is to reduce the supply rate of chrome ore accordingly.

  As described above, according to the present invention, the blockage of the fuel nozzle and the oxygen gas nozzle of the ore charging lance 4 is detected by the pressure increase in the fuel pressure gauge 15 and the oxygen gas pressure gauge 16, and immediately after the blockage is detected. Since the supply of both the fuel and the oxygen gas is stopped, it is possible to prevent a trouble caused by the fuel and the oxygen gas flowing backward through the ore charging lance 4 and the supply pipe.

  Next, a second embodiment of the present invention will be described. FIG. 2 is a diagram showing a second embodiment of the present invention, and is a schematic diagram of a chrome ore smelting reduction equipment provided with a backflow prevention device for a metallurgical lance according to the present invention.

  As shown in FIG. 2, in the iron bath smelting reduction furnace facility 1 </ b> A of the second embodiment, a gas recovery pipe 21 a is connected to an ore containing hopper 20 connected to the upper end of the ore circulation pipe 9. At the other end of the gas recovery pipe 21a, a gas analyzer 21 is arranged as a gas detection means. The gas analyzer 21 determines the composition of the atmospheric gas in the ore containing hopper collected from the gas recovery pipe 21a. The analysis is performed continuously or intermittently, and the analysis result is transmitted to the control device 17, and other than this, it has the same structure as the iron bath type smelting reduction furnace facility 1 of the first embodiment described above, and is the same These parts are denoted by the same reference numerals, and the description thereof is omitted.

  That is, in the iron bath smelting reduction furnace facility 1A of the second embodiment, not only signals from the fuel pressure gauge 15 and the oxygen gas pressure gauge 16 but also signals from the gas analyzer 21 are input to the control device 17. The control device 17 controls the fuel cutoff valve based on both the pressure measurement value input from the fuel pressure gauge 15 and the oxygen gas pressure gauge 16 and the gas composition value input from the gas analyzer 21. 13 and the oxygen gas shut-off valve 14 are closed, the fuel bleed valve 18 and the oxygen gas bleed valve 19 are opened, and the rotation speed of the electric motor 23 is changed to change the chromium ore supply speed to the furnace body 2. To do. In this case, threshold values are set in advance for the pressure and gas composition values, and when either the pressure measurement value or the gas composition value exceeds the threshold value, the above signals are transmitted to the respective devices.

  When the fuel nozzle or the oxygen gas nozzle at the tip of the ore charging lance 4 is blocked due to the scattering of bullion or the like, the pressure measurement value of the fuel pressure gauge 15 or the oxygen gas pressure gauge 16 increases, Although the fuel nozzle and the oxygen gas nozzle are not blocked, the metal ore is attached to the entire lower end of the ore charging lance 4 and the supplied fuel or oxygen gas flows back to the ore circulation pipe 9 through the ore circulation hole. Since the fuel component or oxygen gas component in the atmospheric gas in the storage hopper rises, the blockage can be detected from the gas composition value by the gas analyzer 21 that analyzes this.

  As described above, in the case of the second embodiment, not only the fuel nozzle and the oxygen gas nozzle of the ore charging lance 4 can be detected by the pressure increase in the fuel pressure gauge 15 and the oxygen gas pressure gauge 16, but also. When the entire tip of the ore charging lance 4 is blocked, this blockage can be detected from the gas composition value by the gas analyzer 21, and if any blockage is detected, the fuel is immediately Since the supply of both oxygen gas and oxygen gas is stopped, it is possible to prevent troubles caused by backflow of the fuel and oxygen gas in the ore charging lance 4 and the supply pipe, and further in the ore circulation 9.

  In addition, this invention is not limited to the range of the said description, A various change is possible. For example, in the above description, the fuel nozzle and the oxygen gas nozzle at the tip of the ore charging lance 4 are annular, but a plurality of circular nozzles may be arranged around the ore circulation hole 9. Moreover, although the chromium ore falls and is charged inside the ore circulation hole 9, nitrogen gas or the like may be supplied as the carrier gas together with the carrier gas. Furthermore, the above explanation is an example in which the present invention is applied to the chrome ore smelting reduction method, but what is supplied is not limited to chrome ore, and may be iron ore or nickel ore, It may be a fossilizing agent such as quicklime.

DESCRIPTION OF SYMBOLS 1 Iron bath type smelting reduction furnace equipment 1A Iron bath type smelting reduction furnace equipment 2 Furnace body 3 Top blowing lance 4 Ore charging lance 5 Bottom blowing tuyere 6 Molten metal 7 Molten slag 8 Oxidizing gas supply pipe 9 Ore distribution pipe 10 Fuel supply Pipe 11 Oxygen gas supply pipe 12 Valve stand 13 Fuel shut-off valve 14 Oxygen gas shut-off valve 15 Fuel pressure gauge 16 Oxygen gas pressure gauge 17 Controller 18 Fuel bleed valve 19 Oxygen gas bleed valve 20 Ore containing hopper 21 Gas analyzer 22 Ore supply Conveyor 23 Electric motor 24 Oxidizing gas 25 Chrome ore 26 Flame

Claims (3)

A metallurgical lance backflow prevention device having a burner function, in which an ore circulation pipe for supplying ore is provided in the center, and fuel and oxygen gas flow paths are independently provided around the ore circulation pipe. There,
The fuel supply pipe for supplying the fuel and the oxygen gas supply pipe for supplying the oxygen gas are each provided with a shut-off valve and a pressure gauge, and pressure values measured by these two pressure gauges are input, and A control device for transmitting a fully closed signal to the two shutoff valves based on the input pressure measurement value,
When the pressure measurement value by one of the two pressure gauges exceeds a preset threshold value, the two shutoff valves are configured to automatically close the flow path by a fully closed signal from the control device. An apparatus for preventing backflow of a metallurgical lance having a burner function. A metallurgical lance backflow prevention device having a burner function, in which an ore circulation pipe for supplying ore is provided in the center, and fuel and oxygen gas flow paths are independently provided around the ore circulation pipe. There,
The fuel supply pipe for supplying the fuel and the oxygen gas supply pipe for supplying the oxygen gas are each provided with a shut-off valve and a pressure gauge, and a gas detection means is provided at the upper part or the inlet of the ore circulation pipe. A pressure measurement value by the two pressure gauges and a gas composition value detected by the gas detection means are input, and the two shut-off valves are input based on the input pressure measurement value and gas composition value. A control device that sends a fully closed signal is provided.
When the pressure measurement value by one of the two pressure gauges exceeds a preset threshold value, or when the gas composition value detected by the gas detection means exceeds a preset threshold value, An apparatus for preventing a backflow of a metallurgical lance having a burner function, wherein the two shut-off valves are configured to automatically close a flow path in response to a full-close signal.   The control device is set in advance to ore supply means for controlling the supply rate of ore supplied from the ore circulation pipe at the same time before or after transmitting a full-close signal to the two shut-off valves. 3. The apparatus according to claim 1, wherein a signal is transmitted so as to reduce the supply rate of the ore to the metallurgical furnace, thereby automatically reducing the supply rate of the ore to the metallurgical furnace. A backflow prevention device for metallurgical lances having the burner function described in 1.

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