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March
2006 |
Taphole
Repair Outage at Mittal Steel USA – Burns Harbor
Barry C. Felton, IPO
process and technology manager, Mittal Steel USA – Burns
Harbor, Burns Harbor, Ind. (barry.felton@mittalsteel.com)
The Burns Harbor D furnace taphole was repaired during a scheduled
14-day outage using a “core and plug” technique.
The failure of the taphole, repair options, and preparation
and execution of the outage are discussed. |
Coal
Cost Reduction Using Low-rank Coals
Hardarshan S. Valia,
president, Coal Science Inc., Highland, Ind. (hvalia@comnetcom.net)
High-quality coking coal is currently in short supply, and
prices have risen dramatically. Low-rank coals are lower in
cost and more widely available. The effective use of these
low-rank coals in nonrecovery/heat recovery and byproduct
cokemaking is described. |
Optimum Utilization of Hot DRI: An Innovative Approach
to Integration With Steelmaking Processes
Robert M. Klawonn,
vice president — commercial, and Glenn E. Hoffman, manager
— product development, Midrex Technologies Inc., Charlotte,
N.C. (rklawonn@midrex.com, ghoffman@midrex.com)
KWIKSTEEL® is a process technology capable of converting
iron ore pellets to produce a merchant steel nugget. Future
generations of KWIKSTEEL will develop a continuous link of
hot steel nuggets into a custom melter for continuous production
of liquid steel without the need for oxygen or a strong power
grid. |
United Taconite’s Iron Ore Pelletizing Production
Performance Improvement Project
Thomas C. Dostal, senior
staff process engineer, United Taconite, Forbes, Minn. (tcdostal@cci-united.com);
Lewis M. Gordon, principal application engineer, and Robert
A. Medower, process improvement solutions architect, Invensys
Inc., Foxboro, Mass. (lgordon@foxboro.com)
This article describes the development, commissioning and
results of applying model predictive control in an induration
furnace. Results include the inoculation of the induration
process from feedrate upsets, as well as minimized energy
consumption per ton of product. |
Using Chemical Coal Flow Aids to Handle High-moisture
Coals in a Coking Operation
Thomas Jageman and Mike
Zowacki, U. S. Steel Clairton Works, Clairton, Pa. (tjageman@uss.com,
mzowacki@uss.com); Robin W. Kluck, senior technical adviser,
D. Casey Roe, engineering manager, and Eric P. Zubovic, GE Infrastructure
Water & Process Technologies, Trevose, Pa. (robin.kluck@ge.com,
donald.roe@ge.com, eric.zubovic@ge.com)
This article discusses the chemical treatment by which coal
flow aids function and the improvements realized at a large
coke plant where this treatment has been successfully applied.
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Intercrystalline Stress Corrosion — A Creeping
Threat
Johan van Ikelen (left),
maintenance manager — special projects — blast
furnace department, and Bram Nugteren (right), maintenance
manager — blast furnace department, Corus Strip Products
IJmuiden, IJmuiden, The Netherlands (johan.vanikelen@corusgroup.com)
Many hot blast furnace installations may be in danger of intercrystalline
stress corrosion and the threats it might cause. Detection
methods, repair procedures and monitoring programs are described.
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Hydrogen and Nitrogen Pickup From Ladle Additions
Siddhartha Misra, senior
research engineer, U. S. Steel Research and Technology Center,
Monroeville, Pa.; R.P. Stone, senior product applications manager,
Heraeus Electro-Nite Co., Langhorne, Pa.; M. Kan, management
systems facilitator, Gerdau Ameristeel, St. Paul, Minn.; and
R.J. Fruehan, professor, Carnegie Mellon University
Alloys
and ladle additions such as coke and lime may increase the
hydrogen and nitrogen content of steel. In this paper, several
sources of hydrogen and nitrogen in the ladle were investigated
in order to predict their pickup during these processes. Calcium
hydroxide (hydrated lime) and carburizer, such as petroleum
coke, were found to result in hydrogen pickup. For petroleum
coke, the increase was proportional to the amount of coke
added, and an average hydrogen recovery of about 12 percent
was observed. Addition of ferroalloys, such as medium-carbon
ferromanganese, to the liquid iron was found to increase its
nitrogen content, and a recovery of close to 100 percent was
observed. Similarly, addition of pitch coke, which had a significant
nitrogen impurity, increased the nitrogen content of liquid
iron. Close to 20 percent of the total nitrogen present in
the coke was found to go into the metal.
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