JUN-ICHIRO YAGI

Abstract:

For future progress, this presentation looks back on the research conducted in my laboratory with co-workers at Tohoku University. As the main research subject, a three-dimensional transient mathematical model of the blast furnace was established considering complex transport processes. The model was being developed from two viewpoints of mathematical description/numerical computation and elucidation of elemental phenomena. The model developed has been used to simulate in-furnace phenomena with operation results for improving practical operations and for developing new technology. The blast furnace model has been modified to simulate several the other packed bed processes. The modified model has been used effectively during the development of each process. Some simulation results are explained for a super high-efficiency operation of BF and also for the other moving bed processes. Studies on the elemental phenomena are explained by gas-solid heat transfer coefficient and wet area of the irrigated packed bed. Precise energy evaluation has the possibility to improve energy efficiency in the packed bed processes. Some results of exergy analysis are explained, which is applied to conventional and developing ironmaking processes. Relating to BF, we studied on a rotary cup atomizer with packed bed process to produce granular slag and to recover thermal energy from molten slag and on methanol synthesis from BF off gas. These results showed the possibility to improve thermal efficiency and mitigation of CO2 emission. To summarize above-mentioned items, the mathematical model is a useful tool to improve process efficiency and to develop new technology. However, accurate description of elemental phenomena is prerequisite. From these researches improvement of waste energy recovery and hydrogen application are favorable strategies to decrease CO2 emission from ironmaking industry to protect earth environment from global warming. Keywords: Blast Furnace, Mathematical Model, Exergy, CO2 Reduction