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One goal in any foundry, that transfers metal is to reduce the amount of energy lost in the ladle. With typical air-fuel ladle heating burners, ladles require long preheating times and produce ladle temperatures appreciably lower than the metal temperature. Oxy-fuel burners eliminate these problems due to the highly radiant flame produced by combustion with pure oxygen.
By replacing air with industrial grade oxygen, the nitrogen ballast is eliminated from the combustion process. Oxy-fuel burners provide higher flame temperatures, better emissivity and higher heat transfer. Therefore, oxy-fuel burners are most often used in high temperature processes.
An oxy-fuel burner can rapidly heat a ladle to the metal tapping temperature. This means that instead of superheating the metal to compensate for ladle losses, the metal can be tapped at a lower temperature.
Oxy–fuel burner technology used for ladle preheating has become more common for the following reasons:
1. Faster Heat Up:
Due to the higher available heat, which is defined as the gross energy delivered to the ladle minus exhaust gas losses, a ladle can typically be at temperatures in half the time of a conventional air-fuel burner at the same power. This results in fuel savings and high system flexibility.
2. Higher Ladle Temperature with Energy Savings:
Oxy–fuel burners are excellent in maintaining temperature in hot ladles. The temperature of an air-fuel flame is only 3450F, versus 5000F for oxy-fuel. Due to this fact, and the highly radiant flame of oxy-fuel, more available heat is provided to the ladle. Therefore a higher ladle temperature (up to 2700F) can be achieved in a shorter time with substantially less fuel. This means that the oxy-fuel flame not only maintains a higher ladle temperature, but it can also do it at lower energy consumption.
3. Longer Refractory Life:
Since oxy-fuel provides a ladle temperature much closer to that of liquid iron, there is less thermal shock on the refractory when compared to a standard air-fuel system. As a result, refractory life is usually extended.
4. Reduced Flue Gas Volume:
When combustion air is replaced with oxygen the flue gas volume is drastically reduced. From approximately 11.7 to 3.04 scf of exhaust gas per scf of natural gas, which gives a 75% reduction in flue gas volume - providing a much better environment for your operation.
Other benefits of using Oxy-Fuel burners:
- Elimination of air blowers
- Elimination of electricity consumption for air blowers
- Lower investment costs
- Energy savings in melting furnace
- Flexible ladle heating
- Universal tool for different ladle sizes
- Controllable ladle heating temperature
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