Carbon Requirement for Ironmaking under Carbon and Hydrogen Co-existing Atmosphere

Abstract

The minimum carbon requirement for ironmaking under carbon and hydrogen co-existing condition was discussed. The reaction system consisted of the reductions of iron oxides by carbon monoxide, hydrogen and solid carbon, the partial combustion of solid carbon, and melting of metallic iron and slag. The analysis took into account the equilibrium constrains for the reductions of the iron oxides and thermal requirement to produce hot metal and molten slag. The carbon requirement was plotted against the contributions of solid carbon, carbon monoxide and hydrogen to the FeO reduction. A valley (minimum route) of carbon requirement appeared from the C-CO reduction to the CO-H 2 reduction condition on the ternary diagram, and the requirement got smaller with increase in H 2 contribution. The carbon requirement decreased with lowering the temperature of FeO reduction. The effect of the water gas shift reaction was also analyzed. The water gas shift reaction (direction to generate CO 2 and H 2) decreased the carbon requirement due to its exothermic reaction heat.

Review of hydrogen-rich ironmaking technology in blast furnace

“…Owing to the high reactivity of hydrogen, the reduction ability of H 2 is higher than carbon. However, the direct reduction ability of carbon is improved and water gas reaction [54,55]. …”

A Review on Explorations of the Oxygen Blast Furnace Process

“…It is a well-known fact that the theoretical minimum carbon consumption is the lowest value that still meets the requirements of reducing iron ores and melting metal and slag in a traditional blast furnace (TBF). [4,5] In this process, a proper direct-reduction degree (30-40%) is necessary to supply the CO as reducing gas in the furnace, although the direct-reduction reaction is endothermic and causes an increase in the coke rate. By contrast, in the TGR-OBF, a lower direct-reduction degree and a lower carbon consumption are achieved because the partial pressure of CO is higher in the furnace, which increases the indirect-reduction rate considerably.…”