HFCs/HCs+吸收剂工质对物理化学行为与吸收式动力循环特性

Effective use of mid-low grade heat, e.g. use it for power generation, has huge significant meaning for saving energy and decreasing pollution. Absorption power cycle is a kind of advanced mid-low grade heat/power conversion technology. In this application, the combinations of hydrofluorocarbon (HFCs) or alkanes (HCs)+solvent as well as the combinations of HFCs/HCs +ionic liquid are selected as working pairs, to carry out the fundamental researches on absorption power cycle working pairs, using the approaches of chemical thermodynamics and thermal kinetics. A set of synchronization experimental system will be established, combing Calvet micro-calorimeter and gas-liquid equilibrium device of isothermal synthetic method. The specific heat capacity, solubility and gas-liquid equilibrium data, as well as the heat of absorption/desorption of HFCs/HCs+absorbent working pairs will be determined. Study and establish models of gas-liquid equilibrium and thermal dynamics for describing the high-pressure working pair systems. Clarify the molecular interactions mechanisms and its relationship with key thermophysical properties of working pairs, as well as the physicochemical behavior of absorption/desorption of HFCs/HCs+absorbent working pairs. Carry out the absorption power cycle simulation study on thermophysical properties of HFCs/HCs+absorbent working pairs. Reveal the relative mechanisms between the equilibria thermophysical properties and absorption/desorption kinetic characteristics versus the cycle performance. Provide theoretical supports for developing advanced absorption power cycle driven by the mid-low grade heat.

有效利用中低品位热，将其用于发电，对于节能减排意义巨大。吸收式动力循环是一种先进的中低品位热功转化技术。本申请选择氢氟烃类（HFCs）或烷烃类（HCs)+溶剂组合，以及HFCs/HCs+离子液体组合为工质对，采用化学热力学与热动力学方法，开展吸收式动力循环工质对基础研究。研究建立一套Calvet微量量热计和等温合成法气液相平衡同步测试实验系统；测定HFCs/HCs+吸收剂工质对体系的比热容、溶解度与气液相平衡、吸收/解吸热等基础数据。建立描述工质对体系的高压气液相平衡与热动力学的模型，阐明工质对分子间作用与工质对关键热物性，及其与吸收/解吸过程物理化学行为的关联规律。基于HFCs/HCs+吸收剂工质对热物性开展HFCs/HCs+吸收剂工质对吸收式动力循环的模拟研究，揭示工质对的平衡热物性以及吸收/解吸热动力学特征对循环特性的关联规律，提出工质对创新的方法，为开拓先进吸收式动力循环提供支撑。

吸收式动力循环是一种先进的中低品位热功转化技术，其相关研究近年来形成了国际上关注的前沿热点。在广泛评价了氢氟烃类（HFCs）或烷烃类（HCs）+溶剂组合，以及HFCs/HCs+离子液体组合的基础上，本项目选择具有潜质的HFCs+溶剂组合为主要研究对象，采用化学热力学与热动力学方法，开展了循环工质体系的基础研究。项目组研发了将高压Calvet微量量热计与等温合成法高压汽液相平衡（Vapor-liquid Equilibrium，VLE）装置组合而成的“同步”测试实验系统。同时还研制了高压液相循环法的VLE测定实验系统。选择10种HFCs与9种有机溶剂，构成90个研究体系。利用UNIQUAC活度系数模型，计算了90个体系的超额Gibbs函数。筛选出HFC32、HFC152a、HFC161和HFC245fa等6种HFCs类动力工质；而且，从酰胺类、醚类和酮类等有机物中，筛选出DMF、DMETrEG和NMP等5种吸收剂，获得了30种潜力组合。测定了HFC134a+ DMAC/NMP、HFC152a+DMF/DMAC/DMEDEG/DMETrEG/NMP、HFC161+NMP/DMF/ DMEDEG/DMAC/DMETrEG、HFC245fa+ DMF/DMEDEG/NMP/DMAC等22个体系的VLE数据。以NRTL活度系数模型，拟合了各个实验体系的模型参数，模型化的热力学一致性良好。测定了HFC161+DMETEG/DMETrEG/DMEDEG体系的溶解度与吸收热数据。分析了三个体系的微分吸收焓与积分吸收焓随着溶解度的变化规律，以及吸收过程的吸收速率常数、活化能等热动力学参数的特性。研究了分子间氢键作用和化学结构与体系热化学特性的关联。验证了同步测试实验与热动力学理论分析方法的有效性。基于本课题组此前提出的化学热机概念，借助HFCs/FCs优势动力工质筛选与循环特性模拟的方法，从20种HFCs/FCs动力工质以及4种酰胺类吸收剂中，优选并分析了HFC245fa+DMETrEG、HFC236fa+DMETrEG和HFC161+DMETrEG三个循环的特性。以工质对筛选与循环特性评价，揭示了工质体系关键热物性对循环特性的影响规律。据文献统计，本课题组是国际上发表吸收式动力循环工质体系测试数据最多的研究组。本课题组有关的研究基础工作成果将为开拓先进吸收式动力循环提供支撑。