STUDY OF A BLAST-FURNACE SMELTING TECHNOLOGY WHICH INVOLVES THE INJECTION OF PULVERIZED-COAL FUEL, NATURAL GAS, AND AN OXYGEN-ENRICHED BLAST INTO THE HEARTH

Abstract

Studies were made of features of a blast-furnace smelting technology that involves the injection of natural gas (NG), oxygen (O2) and pulverized-coal fuel (PCF) into the hearth. The technology has been implemented in the compensation and overcompensation regimes, which has made it possible to maintain or improve the gasdynamics of the furnace, the conditions for the reduction of iron oxides, the heating of the charge, and PCF combustion in the tuyere zone as PCF consumption is increased and coke use is decreased. Under the given conditions, with the blast having an oxygen content of 25.64–25.7%, the hearth injection of 131–138 kg PCF and 65–69 m3 NG for each ton of pig iron has made it possible to reduce coke consumption by 171–185 kg/ton pig (30.2–32.7%), reduce the consumption of comparison fuel by 36–37 kg/ton (5.2–5.3%), and lower the production cost of the pig iron by 43–49 hryvnas/ton (3.7–6.4%). Here, furnace productivity has increased 3.8–6.5%, while the quality of the conversion pig iron remains the same as before. Measures are being implemented to further increase the level and efficiency of PCF use.