Posted on 07 Mar 2011
Sumitomo Metals Receives Okochi Memorial Prize for Development of Blast Furnace Technologies
Sumitomo Metal Industries, Ltd. has received the 57th Okochi Memorial Foundation Production Prize for its “development of technologies that extend the campaign life of blast furnaces.”
Blast furnaces are relined after their service life has been reached. Because the reline requires a long repair period (two to four months) and high costs (approximately 30 billion yen), there is great incentive to maximize the campaign life of a blast furnace.
Back in 1982 when the Wakayama Steel Works’ No. 4 Blast Furnace was blown in, the initial plan was to operate it for seven years, based on the expected general service life at that time, which was five to ten years. |
Sumitomo Metals has developed simulation technologies that enable inner conditions to be quantitatively evaluated. Operational and repair technologies based on such evaluations have enabled the Wakayama Steel Works' No. 4 Blast Furnace to achieve the world's longest continuous operation of 10,001 days (27 years and 4 months).
The award has resulted in Sumitomo Metals receiving the Okochi Memorial Foundation Prize for all the processes (i.e. blast furnace, steelmaking, manufacturing mill, and products) that are related to manufacturing of seamless pipes, the company’s major products.
From the early 1970s, Sumitomo Metals worked on finding out the inner activities of a blast furnace, which was then called a “black box.” Since 1991, Sumitomo Metals has developed a variety of new technologies to extend the service life of the No. 4 blast furnace to 20 years or more.
For example, the company has developed blast furnace simulation technologiesthat help to characterize what happens inside the furnace as iron ore and coke are supplied through the top of the furnace and move downward, while hot air is blown in from the side of the furnace bottom. Throughout the furnace, chemical reactions (e.g. combustion and reduction) and physical phenomena (e.g. heat conduction, fusion, and flow) take place, interact in a complex manner, and become balanced. Finally, molten pig iron flows out from the bottom of the furnace.
With the aim of clarifying those factors in a quantitative manner, Sumitomo Metals became the first in the world to develop a simulation model that indicates actual operations precisely by combining mathematical logic with the constantly-changing factors in a three-dimensional manner. Those factors include the temperature of the furnace, reactions and movements of materials, and the flow of molten pig iron and gas.
Sumitomo has also developed technologies to replace traditional blast furnace staves. The body of a blast furnace comprises three layers: the steel shell, staves (cooling devices made of ferrous castings,) and heat-resistant bricks. Previously, damaged staves could not be repaired until the furnace was blown out to be relined. By developing technologies to replace staves at the time of periodical maintenance work, Sumitomo has successfully separated the operating life of staves from the operating life of a blast furnace.
Sumitomo has also developed technologies to inhibit erosion of bricksat the bottom of the blast furnace due to high-temperature (about 1,500oC) molten pig iron and slag. These bricks cannot be replaced until the furnace is blown-out and relined. Sumitomo developed new technologies to extend the operating life of heat-resistant bricks at the furnace bottom by controlling the flow of molten pig iron and slag through the adjustment of the molten pig iron's liquidity and the raw materials' weight balance within the furnace.
In July 2009, the Wakayama Steel Works' No. 4 Blast Furnace achieved the world’s longest continuous operation. Wakayama’s No. 5 Blast Furnace currently has the longest operating life among active blast furnaces in Japan. The technologies that Sumitomo Metals developed have since been applied to the construction and relining of other blast furnaces, namely, the No. 1 and No. 3 Blast Furnaces in the Kashima Steel Works and the No. 1 Blast Furnace in the Wakayama Steel Works.
Sumitomo Metals has offered technical support for the replacement of staves to other steel companies in Japan and overseas, and has contributed to prolonging blast furnace life at other companies.
Established in 1954, the Okochi Memorial Foundation commemorates Dr. Masatoshi Okochi's services to academic societies and industries. The Foundation presents the Okochi Memorial Foundation Prize with the objective to "promote science and technology for production," which was the late Dr. Okochi's wish. The Okochi Memorial Foundation Prize recognizes notable contributions in the areas of production engineering, production technology research and development, and the implementation of high-level production methods in Japan.
