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High capital costs of new blastfurnace installations impose extended campaign life requirements from ironmakers. Although blastfurnace technology is mature, many opportunities for improved design philosophies remain. One of the world's leading blastfurnace suppliers outlines its current best-practice thinking on BF design with reference to its two latest BF projects - in Taiwan and Australia.
In 1993 490Mt of iron was produced worldwide by the blast furnace route compared to just 15Mt by alternative processes (eg, DRI). With the blast furnace predicted to remain the predominant ironmaker well into the 21st Century and stay the first choice of the majority of iron producers, a review of modern furnace engineering is worthwhile.
Davy International has been involved in blast furnace engineering since 1928, and has built 175 new furnaces and undertaken numerous rebuilds and relines. Davy is continually involved in developing new technologies or improving engineering designs. Since 1987 Davy has provided five new blast furnaces to Poseo, S Korea, and has two more under construction at BHP Port Kembla, Australia, and China Steel, Kaohsiung, Taiwan (Table 1). This represents a total capacity of 20Mt/year of iron.
FURNACE DESIGN
The shell of a furnace must withstand high operating and refractory pressures, thermal stresses, burden loads, and have numerous cut-outs for internal water cooling systems connections. Without the most sophisticated design practice the shell would be unacceptably thick to withstand this duty but the use of finite element techniques allows significantly thinner shell plate and an optimised design to give a greater ability to withstand cracking in the latter parts of the campaign (Fig 1).
More recently, redesign of the furnace support structure has lead to a substantially lighter but equally effective design. Such a solution is being used for the first time on the BHP Port Kembla No6 BF (Fig 2).
CASTHOUSE OPERATIONS
The casthouse is an area where considerable effort has been applied to improve the working conditions of the operator and to reduce the number of operators. Modern casthouse design includes flat floors and fully covered runners, the covers being flush with the floor allowing easier use of mobile vehicles in the casthouse (Fig 3).
Labour saving devices, radio controlled equipment and speciality items, such as tap hole drill rod manipulators, clay gun fillers...