Numerical Analysis of the Dust Control Performance of a Counter-current Swirling Configuration in the Flash Ironmaking Reactor
Flash ironmaking technology (FIT) is a potential alternative ironmaking process reducing energy consumption and environmental pollution. The newly proposed counter-current flash ironmaking process has a more reasonable temperature and concentration distribution, while the high dust rate cannot be av...
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Published in | ISIJ International Vol. 62; no. 11; pp. 2225 - 2235 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
The Iron and Steel Institute of Japan
15.11.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Flash ironmaking technology (FIT) is a potential alternative ironmaking process reducing energy consumption and environmental pollution. The newly proposed counter-current flash ironmaking process has a more reasonable temperature and concentration distribution, while the high dust rate cannot be avoided. In this study, a counter-current swirling configuration was introduced to improve the dust control performance. A comprehensive computational fluid dynamics (CFD) model, including gas-particle motion, chemical reactions, particle-wall sticking, slag movement, and wall reaction, was adopted to investigate the velocity vector, temperature, species distribution under the counter-current swirling flow. The effects of initial particle velocity (IPV) and swirl angle velocity (SAV) were analyzed as the crucial parameters. The results show that an annular updraft-center downdraft structure is formed by swirling flow, and the particles are pushed to the wall under the centrifugal force, adhere to the high-temperature wall, and flow down slowly with the molten slag. In the non-swirl cases, the increase of IPV can effectively inhibit the particles escaping ratio from 62.5% to 22.4% and increase the amount ratio of particles leaving the bottom directly with a lower reduction degree. Therefore, necessary swirling flow enhances the high probability of adhesion when the SAV over a varying critical value related to IPV. Also, the long residence time in the molten slag effectively increases the reduction degree of captured particles from 94.3% to 100%. The comprehensive reduction degree of particles increased from 83.3% to 87.3% in a single-cycle reaction. |
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ISSN: | 0915-1559 1347-5460 |
DOI: | 10.2355/isijinternational.ISIJINT-2022-092 |