Ladles or other containers are used to transport liquid metal which cannot reach the next process steps via gutters. These ladles are pre-heated to extend the life of the refractory lining and avoid costly over-heating of the metal bath. Pre-heating temperatures of up to 1200°C are uneconomic with cold air burner systems, and temperatures above 1200°C are difficult to achieve.
In the case of oxyfuel burner systems there is a distinction between their use for pre-heating ladles which are circulated during the production process; and for drying new ladles made of refractory material. The reason for this is the different heat transfer mechanisms at different temperature levels.
Advantages of Oxipyr burner systems at a glance:
Higher combustion efficiency
Faster heating-up times
Lower fuel consumption
Higher processing temperatures possible
Lower exhaust gas levels
Lower production costs
Newly delivered ladles must be heated slowly following heating curves specified by the refractory material manufacturers. Smoke and odor problems caused by the expulsion of the refractory binders can be prevented by internal post-combustion.
Drying newly delivered ladles:
This is carried out at the lower temperature range using oxyfuel with air enrichment, or exhaust gas recirculation. When refractory binders start being expelled, additional oxygen is used for internal post-combustion in the vessel. At the end of expelling the refractory binders, stoichiometric oxyfuel combustion is used.
Natural gas savings with oxyfuel: 30% - 40%
Pre-heating of ladles during production cycle:
Rapid, energy-conserving stoichiometric oxyfuel combustion
Natural gas savings with oxyfuel: 40% - 70%