离子液体复配吸收工质对结构、性质及其热力性能调控

The absorption cycle technology plays an irreplaceable role in recovering and using the low grade heat energy from different sources like industrial process, solar energy and so on. Due to the inherent defects of the extensively used working pairs like water / lithium bromide (corrosion, easy to crystallize, etc.) and ammonia / water (toxic, explosive, etc.), it is very important to find novel absorption workers with the characteristics of safety, environmentally benign, high efficiency for the long period, stable and safe operation of the industrial process and improving the energy efficiency. Therefore, ionic liquids (ILs) that are considered as a novel green solvent will be used as one of absorption workers here and the relationships between the structure properties, the thermodynamic properties of the novel ILs combined working pairs and the thermal performance will be systematically studied with the quantum theory based conduct-like screening model (COSMO). The synergistic effects among ions and molecules interactions and the mechanism of thermal performance manipulation will be deeply discussed. We will then give one thermodynamic method for the descriptions of phase equilibria and thermophysical properties based on the same theoretical framework (The Statistical Association Fluid Theory). After that, the thermodynamic properties of phase equilibria, viscosity, isobaric heat capacity, surface tension for the absorption working pairs will be experimentally determined. At last, the feasibility of the generalized thermodynamic models for the complex mixtures will be checked and verified. This work will improve the application of molecular thermodynamic models in the solution theory and offer more contributions to both process and product engineering.

吸收式循环技术在低品位热能利用中具有不可替代的作用，但由于目前普遍使用的水/溴化锂和氨/水工质对存在腐蚀、易结晶和有毒、易爆等缺陷，探寻高效、稳定、环保的循环吸收工质对对工业过程安全运行和提高能源利用效率具有重要意义。本项目针对近年来快速发展的离子液体材料，从分子微观结构出发，采用基于量子化学理论的COSMO方法建立离子液体复配吸收工质对结构、性质和热力性能间的定性定量关系；深入考察工质对中离子/分子间的协同效应以及热力性能调控机制；基于同一理论框架建立相平衡和热物性的热力学模型；实验测试目标工质对的相平衡、黏度、定压比热容、表面张力等物性数据，论证所建普遍化热力学模型和理论方法的适用性。本项目的实施必将推动热力学模型方法在溶液理论研究中的发展，进一步发挥分子热力学理论在过程和产品工程中的重要作用。

基于化学吸收循环原理的制冷/热泵技术是低品位热能高效利用的重要途径之一。为探寻高效、稳定、环保的循环吸收工质对，项目以离子液体复配吸收工质对为研究对象，耦合COSMO分子模拟和化学吸收循环过程建模方法，探讨了新工质对结构、性质及热力性能间的定量关系；深入考察了工质对溶液中离子/分子作用机制，为新型工质对设计和选择提供理论参考；以变阱宽方阱链流体状态方程为基础，构建了含工质对体系的相平衡、表面张力、黏度普遍化表征模型；耦合制冷/热泵热集成技术，探讨了共沸物高效分离过程设计和节能优化方法；实验测定了离子液体/水工质对体系汽液平衡、密度、黏度和表面张力等基础物性数据，为化学吸收循环过程设计及热力学模型论证提供基础数据支撑。研究工作取得的成果对理解新型离子液体吸收工质对溶液结构、新工质对设计、热能高效利用均具有重要科学意义和实际参考价值。目前已在国内外发表期刊论文14篇，授权发明专利3项，获硕士学位研究生3人，参加会议报告和墙报交流8人次，建设并完善流体相平衡网站(www.equilibria.cn)，项目执行期内网站受访5万余次。