Molten Carbonate Electrochemical Membranes for Low-Carbon Retrofits in the Steel Industry
4 Pages Posted: 4 Apr 2019 Last revised: 25 Apr 2019
In this study, the use of high temperature Molten Carbonate electrochemical membranes is explored as a retrofit post-combustion CO2 capture methodology applied to an existing integrated cycle steel mill. A reference mill of 4 Mton/y of hot rolled coil is considered and its main CO2 emissions sources are identified. In order to evaluate the possible integration strategies between the electrochemical membrane and the steel production process, the three chief CO2 emissions sources are considered: i) power plant (source of about 40%-70% of the total CO2 emissions), ii) coke oven (i.e., 15%-20%), iii) hot stoves (i.e., 15%-30%). A new thermodynamic system layout is envisaged and modelled using an in-house developed simulation tool. The developed model employs a state-of-the-art fuel cell module configuration and adapt it to fit into a new industrial application environment. The fuel cell system is equipped with a gas processing unit able to purify a CO2-rich stream into pure CO2 and hydrogen, available for either reuse or storage. The study finds a thermodynamically interesting operating condition of the proposed system able to comply with the operating constraints of the fuel cell stacks while reducing the direct carbon emission of the steel mill by more than 70%. In addition, a considerable amount of electricity (up to 545 MWel) and hydrogen (up to 346 MWLHV) are produced as additional by-product of the retrofit system. Overall, the proposed system is able to reach a first law efficiency of approximately 60%.
Keywords: Iron & steel, GHGT-14
Suggested Citation: Suggested Citation