Abstract
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Blast furnace ironmaking the major process for new iron production and is likely to remain competitive against alternative ironmaking processes for the coming decades. Further development of blast furnace ironmaking targets decreasing coke consumption and overall CO2 emissions. Nitrogen-free blast and top gas recycling are two potential measures to achieve these purposes. This paper analyses the effects of nitrogen free blast and top gas recycling on the operation of a blast furnace in comparison with a conventional blast furnace. The results show that recycling of top gas consisting of CO and CO2 is an effective measure to control the combustion temperature. However, recycling of top gas will require the combination of an oxyfuel gasifier in which gasification reaction of CO2 and carbon will be carried out and the generated reducing gas heated to 1400 -1700 °C. It not only provides the advantage of utilisation of the reduction capability of the top gas, but also is expected to generate financial benefit by reduction of the operation costs by up to US$5/THM.