高温還元ガス利用による直接製鉄技術

抄録

In July of 1973, a large scale national project* for nuclear steel making has started.
This project will take six years and some 7, 300 million yen. Main organization of research is the Engineering Research Association for Nuclear Steelmaking.
This association studies a total system and five sub-systems, which are heat exchanger, super heat resisting alloys, isoheat materials, reducing gas making and reduced pellts making. The development of Inuclear steel making technology as a national project aims at the completion of a direct-reduction steelmaking pilot plant which will be connected to the multi-purpose high-tempereture gas cooled reactor with a thermal output of 50 MW. With an aim at the above mentioned objective, efforts will be made to develop the design, construction and operational techneques for the pilot plant with a budget of about 7, 300 million yen to cover the relevant expenses for six years, commencing from 1973. To achieve this objective, the firstphase plogram will be directed toward research and development of technologies covering the system design and major components of the plant.
The project, in the meantime, is being carried out so that the 50MWt multi-purpose high-temperature gas cooled reactors being planned by the Japan Atomic Energy Research Institute will attain their full power in 1982. The second phase of this national project accordingly will include the construction and operation plant for nuclear steelmaking to be directly connected to the multi-purpose high temperature gas cooled reactor. After success is achieved in the operation of the pilot plant, the scale of the plant will be expanded so that it will finally be developed into a commercial-scale plant. The period required to attain this prototype scale will be covered by the second-stage program.
The nuclear steelmaking pattern we are expecting to realize is asshown in Fig. 1. Based on the given condition that the temperature of reducing gas to be blown into the reduction furnace should be 800 to 850°C, efforts will be made so that a reactor-outlet herium temperature of 1, 000°C can be guaranteed in consideration of temperature drop in the heat exchanger. The heat of 1, 000°C taken out of the multi-purpose high-temperature reactor will be used through the intermediate heat exchanger for manufacturing and heating of reducing gas. In Japan, the reducing gas will be manufactured from vacuum residual oils because of the scarcity of petroleum and natural gases. As for the steelmaking system has been adopted in which the reduced iron produced by shaft furnaces is turned into crude steel by electric furnaces. With this pattern of nuclear steelmaking, the first-phase progrm, extending over a period of six years, will aim at the completion of research and development of major relevant components such as a high-temperature heat exchanger, heat-resistant superalloys, high-temperature heat insulation materials, reducing-gas manufacturiug units and reduced iron manufacturing unts as well as researches for the development of system design to link the reactor system with the steel making system with a high degree of consistency and safety.
* This Project based upon National Research and development Program by the Agency of Industrial Sciency and Technology, M. I. T. I.