Blast Furnace Hot Stove Heat Recovery Technology for Chinese Steel Industries
Nippon Steel Corporation, Japan
Keywords: Japan, China, steel industry, industrial energy conservation, certified emission reduction, N S
This industrial sector case study is on the technology for energy saving in steel manufacturing, transferred from Nippon Steel Corporation (NSC) to steel industries in the Peoples Republic of China (P.R. China). This project was a part of the Green Aid Plan proposed by the Ministry of International Trade and Industry (MITI), Japan for energy saving and environmental protection in P.R. China. Two examples of actual technology transfer projects illustrate the barriers encountered and countermeasures for overcoming them.
In the Peoples Republic of China, roughly three quarters of the energy consumed comes from coal. The total amount of CO2 emitted in P.R. China is the second highest in the world. P.R. China produces the largest amount of crude steel in the world. But the specific energy consumption for producing each tonne of crude steel is higher than that of some developed countries such as Japan and the US. Japan had achieved a 20% reduction in energy consumption through technology upgrades as early as 1993. Japan supplies steel products to both international and domestic markets with the lowest energy consumption. As a part of the Green Aid Plan to promote energy savings and environmental protection in China, MITI in Japan launched the "Japan - China model project for blast furnace, hot stove, waste heat recovery."
The project, located in Laiwu, demonstrates and disseminates the blast furnace hot stove waste heat recovery technology. The operation of the equipment started in October 1995. The waste heat in the exhaust gas, at a temperature from 200 to 300oC, was recovered and used efficiently to preheat the combustion air and the fuel gas by adopting an organic oil as a heating medium. This process technology can be applied to existing hot stoves of blast furnaces, because the heat exchangers are separately installed and connected with the transfer lines where the hot oil is circulated by pumps. As a result, the operating index has been improved significantly, reducing the fuel ratio of blast furnaces by approximately 7%. Further studies in this area were done for diffusing this technology within P.R. China. For successful implementation, the operating skills were developed under a set of training courses for operators using the actual equipment used in Japan. Through this training, the operators could get information related to both operation and improvement techniques. Japanese engineers were also sent to the site for the further transfer of related information.
Incentives and benefits applied to both NSC and P.R. China. NSC profited through technology upgrade. For P.R. China, facing increasingly competitive international and domestic markets, being able to reduce the cost of steel produced by saving energy while reducing GHG emissions is a positive development . There were certain barriers associated with technology transfer, such as the import of equipment components. It will be beneficial for them to be locally made to cut down the costs. However, these parts purchased domestically could cause some reliability problems.
Maintenance technology is also essential for sound operation. It is important to transfer not only maintenance procedure manuals, but also maintenance skills by providing actual training on-site. For most developing countries, indigenous availability of parts appears to be critical for economic viability and sustainable development.
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