HyS大规模制氢过程多相平衡及其高极性弱电解质热力学模型

混合硫热化学循环(HyS)是目前最具应用前景的高效低成本大规模制氢技术之一。然而准确描述这一非常规条件下高极性-弱电解质复杂体系多相平衡的热力学数据和模型均不完善，分子离子间作用机制不明晰，过程设计和优化缺乏可靠依据。项目拟通过实验系统测定HyS过程中H2SO4，H2O，SO3，SO2和O2在实际工况下的多相平衡和电离平衡数据，完善过程关键热力学数据库，并通过引入准确描述离子间长程作用力和离子溶剂化作用的亥姆赫兹函数以及与组成相关的混合规则，将基于统计缔合流体理论的立方型缔合状态方程扩展到高极性分子-弱电解质共存体系的相平衡计算，对不同相态中的极性分子结构、氢键、静电和溶剂化作用进行合理描述和简化，形成HyS过程专用热力学包，仅需少量参数就能可靠计算HyS过程包含的气液、液液、弱电解质电离、水合物形成等复杂相行为。项目的实施将推动HyS制氢技术开发，也能加深我们对该体系非理想相行为的认识。

The hybrid sulfur thermochemical cycle process(HyS), as a promising large-scale, low-cost and highly efficient hydrogen production technique, has recently become one of the hot spots in hydrogen energy studies. However, there are still many unsolved thermodynamic problems for this highly polar system involving weak electrolytes. Both the fundamental phase equilibrium data and the related electrolyte thermodynamic model that can accurately describe the complex phase behavior are highly demanded. With an eye towards solving these scientific problems, we plan to experimentally determine the complex multiphase equilibrium data of the HyS system conformed by the five components of H2SO4, H2O, SO3, SO2 and O2 at practical working conditions so as to provide reliable data to complete the thermodynamics database for HyS process. Furthermore, we will develop a novel electrolyte associating equation of state on the basis of the well-developed cubic plus association equation by introducing appropriate Helmholtz function and concentration dependent mixing rule to account for the long-range ion forces and ion solvation effect, which could identify the governing interaction mechanisms including solvent environment, ion solvation and hydrogen bonding and electrostatic interactions at molecular level with proper simplifications so as to provide a specially derived thermodynamic model for HyS process that is able to model the complex phase behavior as occurring, including the dissolving and ionization of SO2 in aqueous H2SO4 Solution, the liquid-liquid equilibrium of SO2 and water, the formation of sulfuric acid-water complex with only a few selected adjustable parameters. The implementation of this project will definitely improve our understanding of the hybrid sulfur thermochemical cycle process from the thermodynamics perspective and provide the necessary phase equilibrium data and the related models, which can provide valuable information for the development of this promising process.