Converter co2-o2 mixed injection smelting method and method of dynamically controlling fire point area temperature

Patent metadata

Field	Value
Publication number	US-2022340986-A1
Application number	US-202017049449-A
Country	US
Kind code	A1
Filing date	Jan 21, 2020
Priority date	Oct 16, 2019
Publication date	Oct 27, 2022
Grant date	—

Abstract

The present disclosure provides a converter CO2—O2 mixed injection smelting method and a fire point area temperature dynamic control method. The method realizes online monitoring through an infrared temperature sensor installed inside an oxygen lance, dynamically adjusts the mixing ratio of CO2 and O2 and the height of the oxygen lance position according to the fire point area temperature changes and process requirements in different smelting stages, so that the secondary smelting system interlockingly and dynamically controls the fire point area temperature and the molten pool heating rate.

First claim

1 . A converter CO 2 —O 2 mixed injection smelting method, wherein a converter CO 2 —O 2 mixed injection smelting process comprises a smelting beginning stage, a heating and slagging stage, an early efficient dephosphorization stage, a rapid decarburization stage, and an endpoint control stage; and wherein the converter CO 2 —O 2 mixed injection smelting method comprises:
measuring a fire point area temperature in each of the smelting beginning stage, the heating and slagging stage, the early efficient dephosphorization stage, the rapid decarburization stage and the endpoint control stage, so as to control the fire point area temperature and dynamically adjust a CO 2 mixing ratio.

2 . The converter CO 2 —O 2 mixed injection smelting method according to claim 1 , further comprising:
in the smelting beginning stage, measuring a fire point area temperature T 1 , wherein the fire point area temperature is to be controlled to below T 2 , and the CO 2 mixing ratio is dynamically adjusted based on a difference value ΔT between T 1 and T 2 ; and/or
in the heating and slagging stage, measuring the fire point area temperature T 1 , wherein the fire point area temperature is to be controlled to below T 2 =2800° C., and a molten pool heating rate is to be controlled to within 10-30° C./min, and dynamically adjusting the CO 2 mixing ratio in real time based on the difference value ΔT between T 1 and T 2 and on a heat balance, wherein in response to the difference value ΔT changing by 10° C., the CO 2 mixing ratio is adjusted by 0.5-2.0%; and/or
in the early efficient dephosphorization stage, measuring the fire point area temperature, wherein the fire point area temperature is to be controlled to below 2700° C., and the molten pool heating rate is to be controlled to within 5-18° C./min, and dynamically adjusting the CO 2 mixing ratio in real time based on the difference value ΔT between T 1 and T 2 and on the heat balance, wherein in response to the difference value ΔT changing by 10° C., the CO 2 mixing ratio is adjusted by 0.35-1.8%; and/or
in the rapid decarburization stage, measuring the fire point area temperature T 1 , wherein the fire point area temperature is to be controlled to below T 2 =2700° C., and the molten pool heating rate is to be controlled to within 24-40° C./min, and dynamically adjusting the CO 2 mixing ratio in real time based on the difference value ΔT between T 1 and T 2 and on the heat balance, wherein in response to the difference value ΔT changing by 10° C., the CO 2 mixing ratio is adjusted by 0.3-1.6%; and/or
in the endpoint control stage, measuring the fire point area temperature T 1 , wherein the fire point area temperature is to be controlled to below T 2 =2800° C., and the molten pool heating rate is to be controlled to within 14-30° C./min, and dynamically adjusting the CO 2 mixing ratio in real time based on the difference value ΔT between T 1 and T 2 and on the heat balance, wherein in response to the difference value ΔT changing by 10° C., the CO 2 mixing ratio is adjusted by 0.35-2.0%.

3 . The converter CO 2 —O 2 mixed injection smelting method according to claim 1 , wherein the converter CO 2 —O 2 mixed injection smelting process further comprises a preparation stage; and wherein the converter CO 2 —O 2 mixed injection smelting method further comprises:
calculating an addition amount of a slagging agent and a coolant and formulating an addition system through a material balance and heat balance static model according to a fed metal material condition, a slagging agent condition, a coolant condition and a steel tapping target requirement; and/or
subsequent to a metal charging to the converter, lowering an oxygen lance to a specified height below a converter mouth, introducing a flow of CO 2 and O 2 , controlling the flow of CO 2 and O 2 , and measuring the fire point area temperature.

4 . The converter CO 2 —O 2 mixed injection smelting method according to claim 1 , wherein the converter CO 2 —O 2 mixed injection smelting process further comprises an end stage; and wherein the converter CO 2 —O 2 mixed injection smelting method further comprises:
lifting an oxygen lance to a certain height below the converter mouth, turning off the flow of CO 2 and O 2 , continuing to lift the oxygen lance to a certain height above the converter mouth, and waiting for a next cycle of operation.

5 . The converter CO 2 —O 2 mixed injection smelting method according to claim 1 , further comprising: rocking the converter for steel tapping after molten steel composition and temperature are analyzed to be qualified.

6 . The converter CO 2 —O 2 mixed injection smelting method according to claim 1 , further comprising: installing an infrared thermometer inside an oxygen lance to measure the fire point area temperature.

7 . The converter CO 2 —O 2 mixed injection smelting method according to claim 6 , wherein the infrared thermometer ( 2 - 1 ) is connected to a data processing system ( 2 - 2 ), the data processing system ( 2 - 2 ) is connected to a secondary smelting system ( 3 ), the secondary smelting system ( 3 ) is connected to a CO 2 flow regulating valve ( 4 - 3 ), an O 2 flow regulating valve ( 4 - 4 ) and an oxygen lance control system ( 5 ), and the oxygen lance ( 1 ) is connected to a thermometer protection system ( 6 ) and an oxygen lance cooling system ( 7 ).

8 . The converter CO 2 —O 2 mixed injection smelting method according to claim 3 , wherein the metal material condition in the preparation stage comprises a weight and temperature of molten iron and scrap steel.

9 . The converter CO 2 —O 2 mixed injection smelting method according to claim 7 , wherein a gas supply flow of the oxygen lance ( 1 ) is 6000-100000 Nm 3 /h, where an O 2 concentration is greater than 97%, an O 2 mixing ratio is 50-100%, a CO 2 concentration is greater than 90%, and the CO 2 mixing ratio is 0-50%; and wherein a water flow of the oxygen lance cooling system ( 7 ) is 60-600 m 3 /h.

10 . The converter CO 2 —O 2 mixed injection smelting method according to claim 7 , wherein the infrared thermometer ( 2 - 1 ) transmits an electrical signal of 4-20 mA; wherein the infrared thermometer ( 2 - 1 ) has an infrared spectrum of 4-30 μm, a single laser or dual laser sighting form, and a meter outer diameter of 5-40 mm; and wherein an angle between an infrared axis and a nozzle-orifice axis of the oxygen lance is 0-70°.

11 . The converter CO 2 —O 2 mixed injection smelting method according to claim 7 , wherein: the thermometer protection system ( 6 ) controls a temperature of the infrared thermometer ( 2 - 1 ) to within 0-70° C., a protective gas medium is any one or a mixture of any two or more of N 2 , Ar and CO 2 , a protective gas flow is 500-10000 Nm 3 /h, and a protective gas pipeline inner diameter is 5-200 mm.

12 . The converter CO 2 —O 2 mixed injection smelting method according to claim 7 , wherein the data processing system ( 2 - 2 ) converts the electrical signal of 4-20 mA into a digital signal.

13 . The converter CO 2 —O 2 mixed injection smelting method according to claim 1 , wherein the method is applicable to 30-400 t converter CO 2 —O 2 mixed injection smelting.

14 . A method of dynamically controlling a converter CO 2 —O 2 mixed injection smelting fire point area temperature, wherein a converter CO 2 —O 2 mixed injection smelting process comprises a smelting beginning stage, a heating and slagging stage, an early efficient dephosphorization stage, a rapid decarburization stage and an endpoint control stage; and
wherein the method of dynamically controlling the converter CO 2 —O 2 mixed

Assignees

• Univ Beijing Science & Technology

Inventors

• Zhu Rong
• Feng Chao
• Wei Guangsheng
• Han Baochen
• Dong Kai
• Wang Xueliang
• Wu Wenhe
• Hu Shaoyan
• Li Weifeng
• Jiang Juanjuan
• Dong Jianfeng

Classifications

• C21C2300/06

  Modeling of the process, e.g. for control purposes; CII · CPC title

• C21C5/32 Primary

  Blowing from above (C21C5/35 takes precedence) · CPC title

• C21C2005/4626

  Means for cooling, e.g. by gases, fluids or liquids · CPC title

• C21C5/4673

  Measuring and sampling devices · CPC title

• C21C5/4606

  Lances or injectors · CPC title