ArcelorMittal Newcastle South Africa
Blast Furnace N5, Hot Blast Stoves, Replacement of Ceramic Burners

In February 2014 AMSA awarded an order to HeatTeQ for various repairs of the hot blast stoves of blast furnace N5. The stoves, designed by Krupp Koppers, are of the external combustion type provided with ceramic burners. Included in the scope of repairs was the complete replacement of 2 ceramic burners and 3 hot blast outlets. As the repairs had to be executed with the stoves in hot condition HeatTeQ had to develop special provisions to make this possible.

Facts and Figures

Project: ArcelorMittal Newcastle South Africa
Duration: 3 months
Plant: Hot Blast Stoves Blast Furnace N5
Design: Krupp Koppers
Tonnage: Refractories 250 ton
Execution: May-September 2014
Scope: HBO & Burner Repair
Subcontractor Mechanical: Elinem
Subcontractor Refractories: Anmar

Scope of work

    • Develop methodology for hot repair
      Design, supply and installation of spezialized equipment to facilitate hot repair
    • Demolition and removal as required
      Supply and installation of refractories for new burners and hot blast outlets
      Supply of all required labour
    • Supervision during erection for both the mechanical and refractory scope of work
    • The stove was kept hot by others, in close cooperation with HeatTeQ
    • Underpinning of hot blast outlet refractories
    • Installation of a heat shield to create a safe working environment in the lower part of the burner shaft
    • Complete wrecking and reinstallation of a new hot blast stub and compensator (stove N1 and N3 only)
    • Complete wrecking and reinstallation of hot blast outlet refractories (all 3 stoves)
    • Complete wrecking and reinstallation of the ceramic burner (stove N1 and N3 only)


Summary

The new burners and hot blast outlets had to be installed and repaired with the stoves in hot condition. The stoves were kept hot with auxiliary burners inserted through a bulkhead installed in the top half of the hot blast outlet. To allow working underneath the heat-up burners a safety deck was installed. The high temperatures in the stoves and the limited access required a special design.

Support for the deck was provided by water cooled pipes brought in from the outside through holes drilled through the stove shell and the refractories. These pipes were installed at the elevation of the centerline of the hot blast outlet. The safety deck was designed as a foldable construction to allow installation through the opening between the flanges of the removed hot blast valve.

After bringing the deck in position inside the stove it was unfolded and secured against the wall of the burner shaft. The gaps between the deck and the wall of the burner shaft were closed with ceramic wool. Cool down of the old burner underneath the safety deck took about three days after which demolition and installation could start. After completion of the burner installation a protection floor was placed on top of the burner. On this floor a supporting structure was erected taking over the load of the deck from the water cooled pipe so the pipes could be removed. The deck was then jacked up to an elevation above the hot blast outlet permitting replacement of the hot blast outlet stub and installation of new refractories. The stove heat-up burners were inserted through an opening above the deck so the temperatures in the stove could be maintained during the repair.