In this paper, a novel system integrating direction reduction iron (DRI) production, H2 production, and CO2 capture has been proposed. The novel polygeneration system avoids excessive CH4 conversion rate, and the chemical energy of CH4 is cascade converted. Besides, the system realizes gradual enrichment of CO2 in the CH4 conversion process. This paper presents the exergy analysis of the novel system. It shows that the energy saving ratio of the polygeneration system could reach up to 12.3%, and the performance improvements are mainly attributed to three aspects: cascade utilization of chemical energy, cascade utilization of physical energy, and lower separation penalty. For the polygeneration system, the CO2 concentration could reach up to 65%, and the energy consumption for separation is only about 30% of the general post-combustion separation process. At this point, the CO2 recovery ratio of the system is about 70%.
Keywords DRI, CO2 capture, system integration