JP4370951B2 - Ar gas supply facility for converter blowing and Ar gas supply method for converter blowing - Google Patents

Description

The present invention relates to a supply facility for a converter blown Ar gas and a method for supplying an Ar gas for converter blowing that can change the purity of the Ar gas used in the blowing process of the converter according to the required quality of the molten steel. About.

Conventionally, Ar gas has been actively used in refining processes such as ladle, converter, vacuum refining tank and the like in the steel making process. For example, the Ar-O ₂ blowing method enables decarburization without oxidizing expensive Cr by blowing Ar into molten steel together with O ₂ , and good quality is obtained. It is used in steelmaking as a molten steel method for high Cr steel. Further, not only the above-mentioned Cr-containing steel, but also when refining ordinary steel, for the purpose of improving decarburization efficiency, a method of oxygen blowing while stirring molten steel with Ar gas is adopted.

  Ar gas frequently used in such a steelmaking process is industrially high purity with Ar concentration of 99.999% or more by further concentrating Ar-containing gas obtained from air cryogenic separator with Ar concentrator. It is manufactured (see, for example, Patent Document 1). The high-purity Ar gas purified by the above process is very expensive, and it is desired to use Ar efficiently for refining.

JP-A-5-256570

  The required level of the final product of the molten steel component only needs to match the customer's required quality, and the conventional use of high-purity Ar gas (nitrogen concentration of 10 ppm or less as an impurity) for all molten steel products However, there will be excessive quality, which increases manufacturing costs.

In converter blowing, the required purity of Ar gas differs depending on the steel type, but there is no facility that can be set to Ar gas purity corresponding to it. For this reason, purification energy is consumed more than necessary. The refined energy refers to non-purified Ar separated by an air separator (1) pressurized by a compressor, (2) removed moisture with H ₂ gas, and (3) liquefied Ar with liquefied oxygen. (I.e., heat exchange between liquid oxygen and gaseous argon to liquefy argon), (4) stirring with high-pressure oxygen, removing impurities, storing in a tank as liquefied purified argon, and storing This refers to the energy required for the steps (1) to (6) in which (5) the pressure is increased by a pump, (6) gasified in the gasification step, and supplied to the factory.

  The technical subject of this invention is obtaining the equipment which can change the purity of Ar gas used at the blowing process of a converter according to the required quality of molten steel.

According to claim 1 of the present invention, the Ar gas supply facility for converter blowing is refined from a crude Ar gas produced by an air separation device to a high-purity Ar gas by an Ar purification device, and then blown or blown at the top or bottom. A high-purity Ar gas supply system that supplies the bottom blow converter, a crude Ar gas supply system that bypasses the Ar purification device and supplies the crude Ar gas produced by the air separation device downstream thereof, and a high-purity Ar gas supply A first flow-regulating valve that is arranged downstream of the Ar purifier in the system and adjusts the flow rate of the high-purity Ar gas flowing in the system, and is provided in the crude Ar gas supply system. And a second remotely controlled flow regulating valve for adjusting the flow rate of the crude Ar gas flowing in the system, and the flow rate of the high purity Ar gas flowing in the system provided in the high purity Ar gas supply system. The first flow meter for detecting the flow rate and the rough Ar gas supply system are provided in the system. The second flow meter for detecting the flow rate of the crude Ar gas, and the downstream of the connection point between the coarse Ar gas supply system and the high purity Ar gas supply system, A first gas chromatograph for measuring impurity nitrogen concentration in the mixed Ar gas; a second gas chromatograph provided in the crude Ar gas supply system for measuring impurity nitrogen concentration in the crude Ar gas; Based on each gas flow rate detected by the second flow meter and each impurity nitrogen concentration measured by the first and second gas chromatographs, the impurity nitrogen concentration in the mixed Ar gas is A flow for adjusting the crude Ar gas flow rate and the high purity Ar gas flow rate by controlling the first and second flow control valves so that the set value of the impurity nitrogen concentration according to the required level of the nitrogen concentration of the molten steel component is obtained. A valve control device A.

  In addition, the converter blowing facility Ar gas supply facility according to claim 2 is provided with a check valve for preventing the rough Ar gas from flowing back into the high purity Ar gas supply system.

In addition, the Ar gas supply facility for converter blowing according to claim 3 is provided with a leak prevention valve before and after the check valve in the high purity Ar gas supply system, respectively, and a leak located upstream. A blow pipe is connected between the prevention valve and the check valve, and a blow valve is provided in the middle of the blow pipe.
According to claim 4 of the present invention, there is provided a method for supplying Ar gas for converter blowing using the Ar gas supply facility for converter blowing according to any one of claims 1 to 3. It is characterized by supplying.
According to a fifth aspect of the present invention, there is provided a method for supplying Ar gas for converter smelting to supply oxygen gas and Ar gas during top blowing, bottom blowing or top bottom blowing converter to decarburize molten steel. A method of supplying Ar gas for converter blowing from a crude Ar gas production and supply facility and a high purity Ar gas production and supply facility , the impurity nitrogen concentration in the crude Ar gas, the crude Ar gas and the high purity Ar While measuring the impurity nitrogen concentration in the mixed Ar gas, and detecting the crude Ar gas flow rate and the high purity Ar gas flow rate, respectively, based on the measured value of the impurity nitrogen concentration and the detected value of the gas flow rate, Each flow rate of the crude Ar gas and the high-purity Ar gas used by mixing with the Ar gas is adjusted so as to be a set value of the impurity nitrogen concentration according to the required level of nitrogen concentration of the molten steel component after converter blowing. It is characterized by that.
In addition, the Ar gas for converter blowing according to claim 6 is a crude Ar gas in which the impurity nitrogen concentration in Ar gas is 10 ppm or more, and as high-purity Ar gas, the impurity nitrogen concentration in Ar gas is 10 ppm. It is characterized by using the following .

  According to the Ar gas supply equipment for converter blowing of claim 1, the set value of the impurity nitrogen concentration according to the required level of nitrogen concentration of the molten steel component after the converter blowing is input to the flow control valve control device. Thus, the first and second flow control valves are controlled so that the impurity nitrogen concentration in the Ar gas used in the converter blowing process becomes the set value, and the crude Ar gas flow rate and the high-purity Ar are controlled. The gas flow rate is adjusted automatically. That is, the crude Ar gas and the high purity Ar gas are mixed and used. For this reason, refinement | purification argon consumption is suppressed and the energy consumed for Ar gas refinement | purification can be reduced.

  Further, according to the converter blowing furnace Ar gas supply facility according to claim 2, since the check valve for preventing the rough Ar gas from flowing back into the high purity Ar gas supply system is provided, Backflow into the high purity Ar gas supply system can be prevented.

According to the Ar gas supply equipment for converter blowing according to claim 3, leak prevention valves are installed before and after the check valve in the high purity Ar gas supply system, respectively, and located upstream. Since a blow pipe was connected between the leak prevention valve and the check valve and a blow valve was provided in the middle of the blow pipe, the pressure in the high purity Ar gas supply system Even if the crude Ar gas leaks from the check valve due to a drop in pressure, the backflow can be prevented by the leak prevention valve. Furthermore, the rough Ar gas leaking from the check valve can be blown by opening the blow valve.
Also in the method for supplying Ar gas for converter blowing according to claims 4 to 6, the amount of purified argon consumed is suppressed, and the energy consumed for the purification of Ar gas can be reduced.

Hereinafter, based on the illustrated embodiment, the supply facility for the Ar gas for converter blowing and the Ar gas supply method for the converter blowing of the present invention will be described. FIG. 1 shows an Ar gas supply facility for converter blowing according to the present invention, in which the Ar gas flow is indicated by a solid line, and various signal flows are indicated by broken lines.

  In the figure, 10 is a high-purity crude Ar gas (impurity nitrogen concentration in Ar gas of 10 ppm or more) produced by a well-known air separation apparatus 1 that extracts each gas from the raw material air by utilizing the difference in boiling point, for example. Refined to Ar gas (impurity nitrogen concentration in Ar gas is 10ppm or less) and supplied to degassing equipment (RH), continuous casting equipment (CC) in steelmaking plant and top blowing, bottom blowing or top bottom blowing converter A high-purity Ar gas supply system, in series from the upstream side, the first compressor 2, the Ar purification device 3, the second compressor 4, the first flow control valve 5, the first leak prevention valve 6, A check valve 7, a second leak prevention valve 8, a first flow meter 9, and a first gas chromatograph 11 are arranged, and between the first leak prevention valve 6 and the check valve 7. The piping 12 for blowing is connected to the piping, and in the middle of the piping 12 for blowing A blow valve 13 is provided. In addition, a pipe 14 for supplying high-purity Ar gas to a degassing facility (RH) or a continuous casting facility (CC) is connected to a pipe between the second compressor 4 and the first flow control valve 5. Has been.

  20 is a crude Ar gas that bypasses the Ar purification device 3 and is supplied to the downstream side (in the pipe between the first flow meter 9 and the first gas chromatograph 11) of the crude Ar gas produced by the air separation device 1. This is a gas supply system, and a third compressor 21, an accumulator 22, a second gas chromatograph 23, a second flow meter 24, a second flow control valve 25, and a shutoff valve 26 are arranged in series from the upstream side. Has been.

  This will be described in further detail. In the high-purity Ar gas supply system 10, the first compressor 2 is configured to adjust the gas pressure of the crude Ar gas having an impurity nitrogen concentration of 10 ppm or more (normal value is 5000 to 10,000 ppm) produced by the air separation device 1 to the Ar purification device 3. It has a function of increasing the pressure required to feed into

The Ar purifier 3 removes moisture by sending H ₂ gas into the crude Ar gas whose pressure has been increased by the first compressor 2 and liquefies Ar with liquefied oxygen, so that the impurity nitrogen concentration is 10 ppm or less. It has a function of extracting high purity Ar gas.

  The second compressor 4 has a function of increasing the pressure of the high-purity Ar gas that has been pressurized by the first compressor 2 and purified by the Ar purifier 3 and sending it to the RH, CC, or converter.

  The first flow control valve 5 is a valve for adjusting the flow rate of the high purity Ar gas flowing through the high purity Ar gas supply system 10 and can be remotely operated.

  The check valve 7 has a function of preventing the coarse Ar gas from flowing back from the coarse Ar gas supply system 20 into the high purity Ar gas supply system 10.

  The first flow meter 9 has a function of detecting the flow rate of the high purity Ar gas flowing through the high purity Ar gas supply system 10.

  The first gas chromatograph 11 is arranged on the downstream side of the connection point between the crude Ar gas supply system 20 and the high purity Ar gas supply system 10 and is an impurity in the mixed Ar gas of the crude Ar gas and the high purity Ar gas. It has a function of measuring the nitrogen concentration.

  The first and second leak prevention valves 6 and 8 disposed before and after the check valve 7 and the blow valve 13 are placed in opposite states. Is opened and the blow valve 13 is closed. However, when the detected value of the first flow meter 9 becomes 0, the leak prevention valves 6 and 8 are closed and the blow valve 13 is opened. Thereby, even if the pressure in the high purity Ar gas supply system 10 falls below the pressure in the crude Ar gas supply system 20 and the crude Ar gas leaks from the check valve 7, the leak prevention valve 6 Backflow can be prevented. The crude Ar gas leaking from the check valve 7 can be blown by opening the blow valve 13.

  In the crude Ar gas supply system 20, the third compressor 21 increases the gas pressure of the crude Ar gas having an impurity nitrogen concentration of 10 ppm or more (normal value is 5000 to 10,000 ppm) produced by the air separation device 1 to convert the converter. It has a function to send out.

  The accumulator 22 has a function of storing the crude Ar gas whose pressure has been increased by the third compressor 21 at a high pressure and supplying a necessary amount of the crude Ar gas for diluting the purity as necessary. That is, the accumulator 22 is installed because the amount of crude Ar gas used is larger than the amount of high-purity Ar gas supplied.

  The second gas chromatograph 23 has a function of measuring the impurity nitrogen concentration in the crude Ar gas flowing in the crude Ar gas supply system 20.

  The second flow meter 24 has a function of detecting the flow rate of the rough Ar gas flowing in the rough Ar gas supply system 20.

  The second flow control valve 25 is a valve for adjusting the flow rate of the coarse Ar gas flowing in the coarse Ar gas supply system 20, and can be remotely operated.

  The shut-off valve 26 is a valve that is closed when only high-purity Ar gas is supplied to the converter.

  Reference numeral 30 denotes a flow control device, and the flow rates of the high-purity Ar gas and the crude Ar gas detected by the first and second flow meters 9 and 24, and the first and second gas chromatographs 11 and 23, respectively. Based on the measured impurity nitrogen concentration in the mixed Ar gas and the impurity nitrogen concentration in the crude Ar gas, the first and second flow adjustments are performed so that the impurity nitrogen concentration in the mixed Ar gas becomes the set nitrogen concentration. The valves 5 and 25 are controlled to adjust the crude Ar gas flow rate and the high purity Ar gas flow rate.

  In the Ar gas supply equipment for converter blowing of the present embodiment having the above-described configuration, the flow control valve device sets the set value of impurity nitrogen concentration according to the required level of nitrogen concentration of the molten steel component after converter blowing When set to 30, the flow control device 30 reads the flow rates of the high-purity Ar gas and the crude Ar gas detected by the first and second flow meters 9, 24, and the first and second gas chromatographs. 11 and 23, the impurity nitrogen concentration in the mixed Ar gas and the impurity nitrogen concentration in the crude Ar gas are measured, and the flow rates of these high-purity Ar gas and crude Ar gas, the impurity nitrogen concentration in the mixed Ar gas, and the coarse nitrogen gas are measured. Based on the impurity nitrogen concentration in the Ar gas, the opening degree of the first and second flow control valves 5 and 25 is controlled so that the impurity nitrogen concentration in the mixed Ar gas becomes the set nitrogen concentration. Adjust Ar gas flow rate and high purity Ar gas flow rate That. Thereby, the mixed Ar gas having a set nitrogen concentration is supplied to the converter and used in the refining process.

Thus, in the converter blowing Ar gas supply facility and converter blowing Ar gas supply method of the present embodiment, crude Ar gas and high purity Ar gas are mixed according to the required quality of the molten steel. Used. For this reason, refinement | purification argon consumption is suppressed and the energy consumed for Ar gas refinement | purification can be reduced.

  Further, the check valve 7 can prevent the rough Ar gas from flowing back into the high purity Ar gas supply system 10.

  In addition, leak prevention valves 6 and 8 are installed before and after the check valve 7 in the high purity Ar gas supply system 10, respectively, and between the upstream leakage prevention valve 6 and the check valve 7, Since the pipe 12 is connected and the blow valve 13 is provided in the middle of the blow pipe 12, the pressure in the high-purity Ar gas supply system 10 decreases from the pressure in the rough Ar gas supply system 20 and the check valve 7 Even if the crude Ar gas leaks, the leak prevention valve 6 can prevent backflow. Furthermore, the rough Ar gas leaking from the check valve 7 can be blown by opening the blow valve 13.

A Menoshi stem configuration diagram illustrating a method of supplying the converter supply facilities of Ar gas blowing and Tenro blowing for Ar gas present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air separation apparatus 3 Ar refiner | purifier 5 1st flow control valve 6 1st leak prevention valve 7 Check valve 8 2nd leak prevention valve 9 1st flow meter 10 High purity Ar gas supply system 11 1st Gas chromatograph 20 Coarse Ar gas supply system 23 Second gas chromatograph 24 Second flow meter 25 Second flow control valve 30 Flow control control device

Claims (6)

A high-purity Ar gas supply system that purifies the crude Ar gas produced by the air separation device into high-purity Ar gas by an Ar purification device and supplies it to the top blowing, bottom blowing, or top-bottom blowing converter;
A crude Ar gas supply system that bypasses the Ar purification device and supplies the crude Ar gas produced by the air separation device downstream thereof;
A first flow control valve that is disposed downstream of the Ar purifier in the high-purity Ar gas supply system and that can be remotely operated to adjust the flow rate of the high-purity Ar gas flowing in the system;
A second remotely controlled flow control valve that is provided in the crude Ar gas supply system and adjusts the flow rate of the crude Ar gas flowing in the system;
A first flow meter provided in the high-purity Ar gas supply system for detecting the flow rate of the high-purity Ar gas flowing in the system;
A second flow meter provided in the crude Ar gas supply system for detecting a flow rate of the crude Ar gas flowing in the system;
A first nitrogen concentration measurement device is disposed downstream of a connection point between the crude Ar gas supply system and the high-purity Ar gas supply system and measures a concentration of impurity nitrogen in the mixed Ar gas of the crude Ar gas and the high-purity Ar gas. Gas chromatograph,
A second gas chromatograph provided in the crude Ar gas supply system for measuring the concentration of impurity nitrogen in the crude Ar gas;
Based on the respective gas flow rates detected by the first and second flow meters and the respective impurity nitrogen concentrations measured by the first and second gas chromatographs, the impurity nitrogen concentration in the mixed Ar gas is: The first and second flow control valves are controlled so that the set value of the impurity nitrogen concentration according to the required level of the nitrogen concentration of the molten steel component after the converter blowing, and the crude Ar gas flow rate and high purity are controlled. A flow control device for adjusting the Ar gas flow rate;
A facility for supplying Ar gas for converter blowing.   The Ar gas supply equipment for converter blowing according to claim 1, further comprising a check valve for preventing the crude Ar gas from flowing back into the high purity Ar gas supply system.   Leak prevention valves are installed before and after the check valve in the high-purity Ar gas supply system, respectively, and a blow pipe is connected between the leak prevention valve located upstream and the check valve. 3. A facility for supplying Ar gas for converter blowing according to claim 2, wherein a blow valve is provided in the middle of the blow pipe.   A method for supplying Ar gas for converter blowing using the Ar gas supply facility for converter blowing according to any one of claims 1 to 3. In order to decarburize the molten steel, when the oxygen gas and Ar gas are supplied during top blowing, bottom blowing or top bottom blowing converter, the conversion from the crude Ar gas production supply equipment and the high purity Ar gas production supply equipment In the method of supplying Ar gas for furnace blowing,
Measure the impurity nitrogen concentration in the crude Ar gas and the impurity nitrogen concentration in the mixed Ar gas of the crude Ar gas and the high purity Ar gas, respectively, and detect the crude Ar gas flow rate and the high purity Ar gas flow rate, respectively. Based on the measured value of the impurity nitrogen concentration and the detected value of the gas flow rate , the crude Ar gas is used so that the set value of the impurity nitrogen concentration according to the required level of the nitrogen concentration of the molten steel component after converter blowing is obtained. A method for supplying Ar gas for converter blowing, characterized by adjusting each flow rate of high-purity Ar gas used by mixing with this.   6. Argon for converter blowing according to claim 5, wherein the crude Ar gas has an impurity nitrogen concentration of 10 ppm or more in the Ar gas, and the high purity Ar gas has an impurity nitrogen concentration of 10 ppm or less in the Ar gas. Gas supply method.

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