Extending air-heater life and increasing hot-blast temperature

摘要

In Krivorozhstal blast-fumace shop 1, to increase the period between air-heater (AH) repairs, measures were taken to increase the working life of the packing, the combustion chamber, the dome, the bottom equipment, and the hot-blast pipe. Since ShV-28 fireclay refractory is unsuitable for operation in the packing and in the radial walls and breaks down when steam is supplied with the blast under the packing, its replacement with ShV-37 or ShV-42 refractory is recommended. The lower part of the packing breaks down under the action of the condensing steam added to the cold blast at 60-80 deg C. The harmful influence of moisture may be eliminated if the cold-blast temperature is increased above 100 deg C, by heat insulation of the cold-blast channel and by turning off the cooling units at the air pipelines (in the presence of backup capacity. To improve the working life of the packing for furnace 1, the dust content of the air is investigated: at 30 mg/m~3-it is practically triple the dust content in the blast-furnace gas. Accordingly, an oil filter may be recommended.