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Show 1. Introduction The temperature inside the ladle into which molten steel is tapped from an electric furnace is maintained at approximately 1270K by a gas burner on the ladle cap until the next charge. Because no compact exhaust-heat recovery system that can withstand such a high temperature is available, the high-temperature exhaust gas that is produced after heating the ladle cannot be recycled and is released to the atmosphere. NKK Corporation in collaboration with Nippon Furnace Kogyo Kaisha, Ltd., has developed a method for applying a regenerative burner, which is compact and uses a ceramic honeycomb-structure regenerator, to a conventional ladle heating system. W e recently succeeded in drastically reducing energy consumption (56% reduction in fuel consumption) and reducing costs for refractory materials by uniformly heating the inside of the ladle. This paper describes the application process and effects of the regenerative burner. 2. Application of the Regenerative Burner to the Ladle Heating System 2.1 Background for the application of the regenerative burner A schematic diagram of a conventional burner is shown in Fig. 1. In the conventional ladle heating system, a downward-directed burner is placed vertically, in a position offset from the center towards the side wall, on the ladle cap. The cap is placed on the top of the vertically positioned ladle (3 m diameter x 4 m depth) into which molten steel is tapped from the electric furnace. The air used for combustion is at room temperature, and is supplied by a blower installed inside the building. Since no exhaust-heat recovery system such as a recuperator is installed, high-temperature exhaust gas passes through a flue, which is also placed off-center on the ladle, and escapes into the 2 |
