Nitrogen-free cast iron melting technology with blasting of oxygen and carbon monoxide in a blast furnace

摘要

A plant is comprised of a blast furnace, an air separation unit, a top gas scrubbing facility, and compressor equipment. Nitrogen is removed from the blast furnace by gradually reducing the hot air supply to the blast furnace while increasing the oxygen supply thereto. Subsequently, the top gas from a gas pipe is directed via a gas conduit to the scrubbing facility, where it is cleaned of residual particulates, water and CO2, and wherefrom purified CO is fed into the compressor, after which the CO, which has been compressed to 4.0 bar, is fed into the blast furnace via a lance. Concurrently with this process, a sufficient amount of oxygen is supplied to the blast furnace. CO burns to give CO2 in a crucible of the blast furnace and releases heat which replaces the heat from burning coke (hence saving coke). The blast furnace CO2 is subsequently converted to 2CO, which reduces the iron, and the remaining amount proceeds to the top of the blast furnace. The cycle is then repeated.