ЗАБЕЗПЕЧЕННЯ ЕКОБЕЗПЕКИ МІКСЕРНИХ ВІДДІЛЕНЬ СТАЛЕПЛАВИЛЬНИХ ЦЕХІВ

Abstract

Introduction. Mixer branches of metallurgical enterprises are an intermediate link between blast furnace and steelmaking workshops. They are equipped with mixers – footer containers for storing cast iron melt. In Ukraine, mixers with a capacity of 1300 or 2500 tons are used. Technological operations are accompanied by emissions of finely dispersed brown smoke and large-dispersed graphite dust into the atmosphere. Problem. Mixer compartments of Ukrainian factories are equipped with aspiration systems that dimity emissions from cast iron pouring and draining units with the help of fume tubes, then emissions pass the dust collector and discharge into the atmosphere through a chimney. The main impact of mixer compartments on the environment is: disorganized emission through an aerodynamic dust lamp, which is not allotted by the aspiration system; organized emission through a smoke pipe of dust not caught by a dust collector; solid waste from gas cleaning and dust hoppers settling on the floor and structures of the mixer compartment from the disorganized ejection that did not come out through the lantern. The main problems are insufficient aspiration (disorganized emission) and low emission purification efficiency (emission through the chimney). A separate problem is the disposal of caught dust. The degree of aspiration in the factories of Ukraine is about 0.7 for the filling unit in the mixer and 0.8 for the drain unit from the mixer at the power of the aspiration system 150-250 thousand tons. This does not meet modern requirements. Results. Cyclones are used as a dust collector in most factories, which completely capture graphite, but are not effective enough for brown smoke. Therefore, it is proposed to use sleeve filters or electro filters. It is also possible to introduce the suppression of brown smoke with nitrogen. The use of nitrogen is possible in accordance with cyclones (for existing systems) or compatible with filters (during reconstruction or new construction). The use of suppression of brown smoke with nitrogen allows to solve the problem of disposal of caught dust, because nitrogen supply leads to enrichment of dust with graphite. The content of graphite increases from 15% to more than 30%, which converts dust from care to commodity product. Keywords: mixer, cast iron pouring, cast iron drainage, dust suppression by nitrogen, aspirational mixer compartment system.