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A top fired walking beam furnace rated at 75 t/hr was fitted with
12 Hauck
SVG125 burners
in the charge section of the furnace. Each burner was rated at nominal 1MBtu/hr each. The
burners were fired with ambient temperature combustion air. The firing rate of the burner was controlled using a two position solenoid valve in the
combustion air supply and each valve was fitted with a mechanically set low and high fire
setting. The rising and falling pressure of the combustion air at the burner was used to
control the amount of gas at the burner and each of the
SVG burners was ignited
using a spark electrode supplied with the burner.
IMPLEMENTATION
The modifications of the furnace included the installation of the new burner systems;
the extension of the heating chamber of the furnace by six feet; and the replacement of
the loading skids with water cooled skids. The high velocity burners were installed in
prefabricated modules designed to accommodate two burners per module. The burners were
fitted prior to installation of the module on the furnace. High Velocity Burners were also installed at the old baffle wall. These burners were
completed in a similar fashion to the charge end modules. Only minor steel work
modifications were required in this area.
CONCLUSION
This is a unique example of the technique of high intensity convective heating for
generating significant material preheating which can be used to increase the production
rate of a furnace. The mathematical developed for this application predicted a production
increase of 17% and the furnace has now consistently demonstrated sustained production
rates over 22% greater.
Oxidation rates will be gradually improved by the installation of Level II controls.
There was also a small improvement in the specific fuel consumption of the furnace.
The static thermal model developed for this project is a reliable tool for the
prediction of the performance of the modified furnace. The use of the high velocity
burners in the mixing zone was an effective substitute for the customary baffle wall. In
addition, the removal of the baffle wall removed the shadowing effect on the incoming
load. The extra turbulence in the mixing zone also had a significant impact on the amount
of heat removed from the POC as it is vented from the furnace.
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