Hydrogen Utilization for Carbon Recycling Iron Making System

A new energy transformation concept based on carbon recycling, called the Active Carbon Recycling Energy System, ACRES, had been proposed for a zero carbon dioxide emission process. A smart ironmaking system based on ACRES (iACRES) was discussed thermodynamically. Efficient regeneration of carbon material from carbon dioxide (CO2) emitted from ironmaking system was a key technology for establishment of iACRES. Carbon monoxide (CO) was the appropriate carbon material in recycling system of iACRES because CO had high enthalpy for reduction of iron oxide. CO regeneration by CO2 hydrogenation was employed for carbon recycling because the regeneration was the most practical technology in regeneration ways. Equilibrium analysis for CO recycling in iACRES was discussed. Effluent gas of an iron making process is generally mixture of CO2 and CO. Effect of concentration of CO2 in gas for reduction on CO regeneration was discussed. CO2 had small negative effect on CO reduction. Then, CO and CO2 separation process for effluent gas from ironmaking process was capable to be omitted in iACRES. The omission of the process would realize simplification and cost-reduction of processes in iACRES. A structure of iACRES using external H-2 and high-temperature heat was proposed. It was shown that hydrogen was useful material as reductnat for CO2 reduction in iACRES.