electric furnace bottom blowing world development course:

In the 1980 s, companies such as Thyssen Krupp Steel Company in Germany and Union Carbide Company in the United States tried to install bottom blowing devices at the bottom of the electric arc furnace, but their longevity and safety issues were not resolved. In the early 1990 s, the Central Iron and Steel Research Institute put forward the concept of "top-bottom combined blowing of electric arc furnace", that is, based on power supply, oxygen blowing above the molten pool and argon blowing at the bottom of the furnace are used to achieve energy saving and consumption reduction in electric arc furnace steelmaking. The research was once established as the "Seventh Five-Year Plan" project of the Ministry of Metallurgical Industry, and industrial tests were carried out in the electric arc furnace of Great Wall Special Steel Company, but the project failed to achieve engineering due to various technical reasons. At the same time, the non-contact bottom blowing developed by Thyssen Krupp in Germany in 1992 was successfully applied in a steel company in South Africa, and the economic effect was also very significant, but the technology was not promoted. In addition, research on bottom argon blowing in the 165-ton electric furnace of the Dofasco double furnace shell in North America has also been carried out, as shown in the figure below.

Its flow test is especially worthy of our reference, as shown in the figure below.

The main test results are as follows:

In 2007, according to the current situation of electric arc furnace steelmaking at home and abroad, Beijing University of Science and Technology proposed "electric arc furnace steelmaking composite blowing technology" on the basis of preliminary research, and gave new technical connotation, that is, taking the new technology of cluster oxygen supply application and the multi-medium bottom blowing technology of synchronous longevity as the core, realizing the operation integration of power supply, oxygen supply and bottom blowing and other units, meeting the technical requirements of electric arc furnace steelmaking composite blowing technology under multiple charge conditions, and from the beginning of 2011 to achieve engineering. With the development of this technology, more and more companies have developed bottom blowing argon technology, including Feilong Technology, Shengda Metallurgy, Hengyang Technology, Jiangsu Hengli, Tonglian Metallurgy, Changchun Electric Furnace, Apu Electric Furnace, etc., as well as many manufacturers' own design and production of bottom blowing argon. According to what I have seen, the problems that need attention include the following aspects:

1) Flow setting problem. Everyone is using the flow rate of 5-500NL/min. We can compare the flow rate of 10NL/min with that of dofasco165 tons of electric furnaces abroad. The company has done many years of tests at different flow rates and finally set the flow rate of 10Nl/min.

2) Argon leakage problem, no leakage is allowed under the flow rate, the direct way is welding, welding will not leak, and there is no need to check.

3) Arcing problem, some electric furnace grounding wire has problems, bottom blowing to do insulation will reduce a lot.

4) The blockage problem, due to the blockage problem caused by single-shift production, can be solved by opening argon all the time. Other blockage problems should be carefully judged, and it is generally believed that there is leakage.

5) The effect problem, too many domestic electric arc furnaces with good indicators are not equipped with bottom blowing argon, so the effect is controversial. The flow rate of argon blowing at the bottom of the furnace is 3 orders of magnitude different from the jet flow rate of the cluster oxygen lance. Which of the heat transfer and mass transfer effects is better can only be seen in the long run. Facts speak louder than words.