Flow sheet model evaluation of nuclear hydrogen steelmaking processes with VHTR-IS (Very High Temperature Reactor and Iodine-Sulfur process)

Kasahara, Seiji  ; Inagaki, Yoshiyuki; Ogawa, Masuro

Flow sheet model evaluation of nuclear hydrogen steelmaking (NHS) and nuclear hydrogen partial reduction steelmaking (NHPRS) systems applying VHTR-IS (Very high temperature reactor and iodine-sulfur process) was carried out. Heat input and CO emissions of these systems were analyzed. Total net heat input to the NHS system was 28.4 GJ/t-high quality steel (HQS), including material production, material transportation, and power generation. This value was much larger than that of blast furnace steelmaking (BFS) system of 17.6 GJ/t-HQS. Reduction of hydrogen consumption in the shaft furnace and electricity consumption in the electric arc furnace were desired for lowering the heat input. Total net heat input of the NHPRS system was 31.9 GJ/t-HQS. Optimization of operation parameters such as reduction ratio of partial reduced ore (PRO) and PRO input ratio to the blast furnace is desired to decrease the heat input. CO emissions from the NHS and the NHPRS systems were 9% and 50% of that from BFS system. Substitution of hydrogen for coal and reduction of transportation weight contributed to the reduction. Steelmaking cost was also evaluated. When steelmaking scale of each system was unified to one million t-HQS/y, NHS was economically competitive to the BFS and Midrex steelmaking. And NHS was advantageous at higher cost of resources.