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Sumitomo Metals Honored for Development of Advanced Stainless Boiler Tube

03/13/2009 - Sumitomo Metal Industries is awarded the 55th Okochi Memorial Foundation Grand Production Prize for its development of advanced stainless boiler tube that enables high efficiency operation of ultra-supercritical coal-fired thermal power plants.

Sumitomo Metal Industries, Ltd. was recently awarded the 55th Okochi Memorial Foundation Grand Production Prize for its development of advanced stainless boiler tube for ultra-supercritical (USC) coal-fired thermal power plants.

The Okochi Memorial Foundation,  which commemorates Dr. Masatoshi Okochi's services to academic societies and industries, was established in 1954.
 
In support of the late Dr. Okochi's wishes to "promote science and technology for production," the Foundation presents the Okochi Memorial Prize in recognition of notable contributions in the areas of production engineering, production technology research and development, and the implementation of high-level production methods in Japan.
 
The Okochi Memorial Foundation Grand Production Prize, the highest honor among the Okochi Production Prizes, is awarded to an outstanding industrial achievement that is based on distinguished innovative corporate research.
 
This is the third time that Sumitomo Metals has received this award.

The company’s boiler tube enabled a breakthrough advance from the conventional supercritical (SC) power plant to the USC plant, for the first time in about 30 years. Today, the developed boiler tube, which has become an industry standard, enables thermal power plants throughout the world to achieve highly energy-efficient operation. The boiler tube also helps thermal power plants to significantly reduce both CO2 emissions and coal usage.
 
A critical factor in achieving higher energy efficiency in power generation is attaining both high temperature and high pressure in the steam generated in the boiler. Conventionally, power plant’s heat efficiency has been in the range of around 41% in the supercritical condition with a temperature of 566° Celsius and pressure of 24.1MPa. These conventional plants typically use steel containing 18% chromium for the boiler tube.
 
In contrast, Sumitomo’s boiler tube—which offers high resistance to both steam oxidation and outer high-temperature corrosion, as well as high-temperature resistance—allows power plants to attain a power generating efficiency of about 43%, under the more rigorous ultra-supercritical conditions. The boiler tube uses a fine-grained 18%Cr steel developed by Sumitomo Metals. The steel is produced using a unique control technology to precipitate niobium carbide that results in high-temperature strength and steam oxidation resistance. The company later advanced its technology by developing a significantly stronger steel that contains copper and has demonstrated the highest-strength achieved to date for steel for this application.

Sumitomo Metals further developed its steel using nitrogen and niobium to produce a new 25%Cr steel that excels in high-temperature corrosion resistance. This version was developed to enable usage in boiler tube for high-sulfur-content coal combustion boiler. Following extensive, long-term field testing, Sumitomo Metals’ newly developed steel tubes have now been registered in the major world standards.

In terms of manufacturing technology, the new steel tube materials require unprecedented high-temperature heat treatment and high-reduction cold drawing processing technology. Sumitomo Metals developed the necessary process technologies to enable mass production, in addition to improving the performance of the heat treatment furnace.

In 2007 Sumitomo Metals constructed a new stainless boiler tube plant, where the internally developed mass production technologies have been introduced, at the Steel Tube Works (Amagasaki). The plant is currently operating at full capacity.

Sumitomo Metals' boiler tube has played a significant role in realizing the construction of ultra-supercritical power plants. A total of 191 USC power plants, including 22 in Japan, have already adopted, been supplied with, or decided to adopt the tube. At each location, adoption of the improved boiler tube has helped the facility to reduce CO2 emission and coal usage.