The development history of the bag baking machine

Ladle roaster is a device used for roasting the ladle after it is newly laid and before the molten steel is poured in, also known as ladle roaster. There are two mainstream types of ladle roasters: line roaster and line roaster. There are two types of line baths: vertical bath and horizontal bath. In addition, there is a tundish roaster designed specifically for tundish roasting.

The baking device of the ladle roaster is one of the main links in the steelmaking process. The performance of the roasting device has a great influence on the converter temperature, working rate and furnace age. The oven is between steelmaking and casting, and the temperature of the oven plays an important role in the coordination of the entire production, especially in continuous casting. Before pouring, the molten steel should be left to stand in the ladle for 5 to 10 minutes. During the calming process, the temperature of the molten steel will decrease, and there are three types of heat loss: heat loss on the upper surface of the molten steel, comprehensive heat loss on the surface of the ladle shell, and heat loss of the ladle lining, of which the heat loss of the ladle lining accounts for about 40% to 50% of the total heat loss. Therefore, reducing the heat loss of the ladle can greatly reduce the temperature drop of the molten steel in the ladle. It is of great significance to reduce the temperature of steel, extend the life of converter, increase the output of steel, reduce the consumption of raw materials, reduce the cost of tonnage steel, and ensure the smooth progress of continuous casting.

The ladle baking device has undergone a series of development processes from using only gas pipelines to using ordinary burners, high-speed burners, hot air burners, self-preheating burners, and regeneration burners. Most steel mills built in the 1950s and 1960s did not have ladle baking equipment, or only used a gas pipe to insert the ladle for baking. Due to the low ladle baking temperature, high steel tapping temperature, low furnace age, long smelting time, limited steel output, and increased costs.

During the "Seventh Five-Year Plan", the metallurgical department proposed new equipment and new processes for ladle baking, which greatly improved the level of ladle baking in my country. Most enterprises changed the baking process that used only gas but not air in the past, so gas and oil ladle baking equipment appeared. Its burner types include jet burners and sleeve burners, and a ladle cover is installed on the ladle to reduce heat loss. Due to the small kinetic energy of the burner flame, the temperature distribution of the ladle is uneven, the baking time is long, and the fuel consumption is large.

The ladle baking device is one of the new technologies that have made breakthroughs in modern thermal technology. Its characteristic is that the combustion gas outlet velocity can reach 100 ~ 300 m/s. When heating objects, the heating effect is much better than that of ordinary burners, both in terms of heating speed and heating uniformity. Due to the high outlet speed of high-speed burners, large consumption of refractory materials, and short service life of burners, the on-site environment of ladle baking equipment in general steel plants is relatively poor, and it is not suitable for installing precision control equipment.

In order to further reduce energy consumption, flue gas is used to preheat air or gas baking furnace production. There are two structures: one is a burner separated from the heat exchanger, and the other is a self-preheating burner. Preheating air or gas can increase the theoretical combustion temperature of the flame, reduce fuel consumption, and maintain the characteristics of high-speed burner flame kinetic energy and uniform heating, so the application of heat storage baking device is becoming more and more extensive.