S-I thermochemical cycle: A thermodynamic analysis of the HI-H sub(2O-I) sub(2) system and design of the HI sub(x decomposition section)

• Published in: International journal of hydrogen energy Vol. 34; no. 5; pp. 2121 - 2132
• Main Authors: Lanchi, M, Ceroli, A, Liberatore, R, Marrelli, L, Maschietti, M, Spadoni, A, Tarquini, P
• Format: Journal Article
• Language: English
• Published: 01-03-2009
• Subjects: Assessments; Atmospheric pressure; Barometric pressure; Decomposition; Electrolytes; Mathematical models; Separation; Thermodynamics
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2008.11.029

It is widely agreed that the most energy consuming part of the Sulphur-Iodine (S-I) thermochemical cycle for hydrogen production is represented by separation processes, especially for the HI decomposition section (HI sub(x section). Therefore, the assessment of the real potential of the S-I cycle requires an optimization of the separation sections and, hence, a deep knowledge of the thermodynamic behaviour of the systems to be separated. In this paper, a new thermodynamic model for the electrolyte system HI-H) sub(2)O-I sub(2 is proposed and validated on vapour-liquid (V-L) equilibrium data at atmospheric pressure. The model provides a reliable description of the phase equilibria of the ternary system and is applied for the flow-sheeting of the HI) sub(x) section at atmospheric pressure along with the energy assessment of the proposed scheme.