Perfection of equipment and technology of steel ladles lining drying and heating to neutralize emissions of organic binders decomposition products

Technological operations of steel ladles lining drying and heating are accompanied by formation and emission of compounds, referred to the first and second category of danger. This is attributed mainly to the presence in the refractory’s composition phenol-formaldehyde tars and coal pitch as binders. Results of simulation of steel ladle lining heating operation presented. The filtration speed distribution of decomposition products in the lining material established. The main part of harmful substances from the lining is emitted in the process of its drying into internal working space of the ladle. Less than 10% of the total amount of pollution substances goes out through the external evaporating openings in the ladle armor. It was shown, that within near 90% of drying and heating time, the temperature in the ladle does not exceed level of 800 °С, which is not enough for harmful substances afterburning. Reasonability of afterburning of the formed harmful emissions justified as a separate technological element of the facility of ladles drying. For the afterburning, not expensive materials should be used, having catalyst properties and developed surface. Application of catalyst enables to decrease the minimum necessary temperature for oxidation of decomposition products down to 600-650 °С. Description of the facility, developed by Concern “Jet Technologies”, for ladles drying and heating with neutralization exhausted technological gases presented. The facility has an airtight shelter, in which a ladle with new lining is placed. The shelter has a lifting cover, in which a gas-air burner is installed. The burner can operate with a high excess of air to provide minimal temperature of drying agent at early stages of drying. Inside the shelter a negative pressure is kept for active removal technological gases and prevention of penetrating them into the working zone of the shop. The power of the burner is controlled by the temperature, measured by a thermo-converter in the cover. Out of the shelter the technological gases are directed to a thermocatalyst reactor (TCR). The TCR has another burner for additional heating of gases leaving the ladle, to the afterburning temperature. Power control is made also based on the measured temperature. After completion of emitting binder decomposition products, the TCR is switched off. After neutralization in the TCR, the technological gases are emitted into atmosphere through a smoke stack. The facility operation control is made by a local control system, based on an industrial logic controller. At the EAF-based plant “NLMK-Kaluga”, the ladles with phenol-based binder lining are successfully dried for many years already at a facility described in the paper, providing an ecological safety of the emissions.