A new pathway to produce hydrogen with CO capture from blast furnace gas via SOFC-SOEC integration

As a low calorific value fuel, blast furnace gas (BFG) is worthy of utilization in a clean, efficient, and low-carbon manner. In this study, a new approach that can achieve value-added recycling of BFG, BFG → SOFC-SOEC → H2, is put forward with hydrogen production and carbon oxides capture. The system mainly consists of blast furnace (including upper, middle, and lower units), SOFC, and SOEC modules, which can convert low-grade chemical energy of BFG into electricity and then into hydrogen. Feasibility verification and parameter optimization of the proposed system is conducted using ASPEN Plus software. The effects of C and CaCO3 feeding rates, blast furnace temperature, air flow rate, and O2 flow rate are comprehensively investigated. Results indicate the feasibility of integrating SOFC with SOEC for value-added hydrogen production. Moreover, carbon oxides capture efficiency of 99.92 %, BFG lower heating value of 2209 kcal/m3, SOFC efficiency of 61.1 %, SOFC power of 65 kW, and H2 production rate of 0.24 kmol/kmol·BFG can be obtained under the conditions of C/CaCO3 = 42.6 and oxygen feeding rate = 11.58 kmol/ton·ore. These findings provide valid strategies for BFG-to-hydrogen production with COx capture via SOFC-SOEC integration, which may substantially promote the low-carbon BFG conversion and diversified utilization.