【作者】 陈伟；

【导师】 唐大伟； 梁世强；

【作者基本信息】 中国科学院研究生院（工程热物理研究所） ， 工程热物理， 2014， 博士

【摘要】 随着能源短缺与全球变暖等环境问题的日益严峻,吸收式制冷循环作为一种高效、安全的中、低品味能回收利用技术而备受世界各国能源工作者的关注。传统的吸收式制冷系统自身存在的低温结晶、高温腐蚀,压力偏高、精馏降效等缺陷,使其在实际工业应用的过程中受到了较大的限制。离子液体是室温下为液态的盐,具有独特物化性质,无可测量蒸气压、无腐蚀性,具备作为吸收剂的潜能,可以完美克服现存机组的一系列缺陷。近年来,离子液体型制冷工质对的研发已近成为一个国际性的研究热点。在国家高技术研究发展计划资助项目(863, No.2007AA05Z259)《离子液体型吸收式冷水机组研发》的资助下,前期工作中已经筛选出了具有商业应用潜质的吸收式制冷工质对[mmim]DMP/CH3OH,并研究了该工质对的气液相平衡性质。在此基础上,本人又展开了深入的研究：1.基于[mmim]DMP/CH3OH溶液的气液相平衡数据,建立了能够在整个浓度范围预测[mmim]DMP/CH3OH溶液蒸气压参数的UNIFAC模型和预测过量焓参数的Wilson模型。并对[mmim]DMP/CH3OH吸收式制冷单效循环热力特性进行了仿真分析。2.在常温下测量了不同摩尔浓度的[mmim]DMP/CH3OH(?)[mmim]DMP/H2O溶液热导率,关联了预测溶液热导率的Random Mixing模型。3.基于[mmim]DMP/CH3OH溶液的气液相平衡性质以及热导率参数,对双效串联、并联[mmim]DMP/CH3OH吸收式制冷系统进行了动态建模与仿真模拟,并将仿真结果与文献实验结果进行了对比。研究结果表明：[mmim]DMP/CH3OH单效制冷循环COP略低于LiBr/H2O系统,但在整体上要高于NH3/H2O系统。离子液体的加入显著地提高的甲醇的导热性能,这有利于系统热力性能的提高和系统参数的优化设计。通过对比表明,双效吸收式制冷的动态模型可以较好的描述双效制冷系统的稳态和瞬态特性,并能满足系统优化和实时控制设计的应用需求。常规的离子液体对制冷剂的吸收能力有限,极大的限制了工质对循环效率的提高。为了更进一步提高制冷剂在离子液体中的吸收量,我们提出了一种以NH3为制冷剂,离子液体[bmim]Zn2Cl5为吸收剂的物理吸收和化学吸附复合机制的新型离子液体制冷工质对,并且得到了国家自然科学基金(No.51276180)《吸收与络合吸附复合作用的离子液体型化学热泵工质对研究》的资助,相关研究内容如下：1.搭建了[bmim]Zn2Cl5/NH3饱和气压测量装置,应用静态法测量了其在323.15～563.15K温度范围内的饱和气压,并用UNIFAC模型进行了关联拟合,根据关联模型绘制了二元溶液的P-T-x图。2.对[bmim]Zn2Cl5进行了TG-DSC扫描,验证离子液体的热稳定性并得到其比热容参数。测量了[bmim]Zn2Cl5/NH3在288.15～333.15K温度范围内的过量焓参数,并用NRTL模型进行了关联拟合。3.基于[bmim]Zn2Cl5的比热容参数、[bmim]Zn2Cl5/NH3的蒸气压和过量焓参数,对[bmim]Zn2Cl5/NH3吸收式制冷单效循环热力特性进行了仿真分析,并与NaSCN/NH3吸收式系统进行了对比。结果表明：NH3在[bmim]Zn2Cl5中的溶解度要远远高于在其他常规离子液体中的溶解度,且[bmim]Zn2Cl5的比热容较低,[bmim]Zn2Cl5/NH3溶液的过量焓适中,这都有利于[bmim]Zn2Cl5/NH3吸收式系统热力性能的提升。通过理论循环分析发现：[bmim]Zn2Cl5/NH3吸收式系统的热力性能要优于NaSCN/NH3吸收式系统,且该系统在制冷温度较低的制冷工况和吸收温度、冷凝温度较高的热泵工况下均具有良好的热力性能和可接受的的循环倍率。总之,[bmim]Zn2Cl5/NH3工质对具有很大的工业应用潜质和良好的商业开发前景。更多还原

【Abstract】 With the energy shortage, environmental problems and globe warming becoming increasingly serious, absorption refrigeration technologies have attracted more and more attention from the energy researchers all over the world because of their advantages of environmental friendly and utilizing the low grade energy. The most widely-used working pairs are H2O/LiBr and NH3/H2O. Because of the inherent defects of crystallization, corrosion and toxicity, applications of traditional working pairs, H2O/LiBr and NH3/H2O, are largely limited. Ionic liquids possess distinctive properties of negligible vapor pressure, good thermal stability, no corrosion, no crystallization and favorable solvating properties, which make ionic liquids to be excellent alternatives for the traditional absorbent.Supported by the National High Technology Research and Development Program of China (863, No.51276180), ionic liquid working pairs of [mmim]DMP/CH3OH with great potential for commercial applications have been screened out and the vapor-liquid equilibrium of [mmim]DMP/CH30H has been investigated. On the basis of preliminary research results, further researches have been conducted.1. Based on the vapor pressure data of [mmim]DMP/CH30H, the UNIFAC model and the Wilson model, which are used to predict the vapor pressures and excess enthalpies of [mmim]DMP/CH3OH, respectively, were correlated. The investigation on the thermodynamic performances of [mmim]DMP/CH3OH absorption refrigeration were conducted.2. Thermal conductivities of [mmim]DMP/CH30H and [mmim]DMP/H20with different mole fractions of [mmimJDMP were measured by3ω method. The experimental data were correlated by the Random Mixing model.3. The dynamic modeling and simulation based on components for parallel type and series type double effect absorption refrigeration using [mmim]DMP/CH30H were conducted. The simulation results were compared with the experimental results in literature.From the above mentioned work, some conclusions were obtained. The COP of [mmim]DMP/CH30H cycle is lower than that of LiBr/H2O cycle, but generally higher than that of NH3/H2O cycle. The adding of [mmim]DMP into CH3OH can remarkably enhance its heat transfer performance, which is conducive to improve the thermal performances of [mmim]DMP/CH30H cycle. Through the comparison to the experimental results in literature, it is indicated that the dynamic model well describes the characteristics of the systems and can be used to the further parameter optimization and control designment.Generally speaking, the solubilities of refrigerant in the common ionic liquid are not very high, which is an obstacle to improvement of thermal performances. In order to improve the solubilities of refrigerant in ionic liquid, the working pairs with NH3as refrigerant and [bmim]Zn2Cl5as absorbent were proposed, which involve both physical adsorption and chemical absorption mechanisms. The research has been supported by the National Natural Science Foundation of China (No.51276180), and the related researches are listed as follows:1. The device of vapor pressure measurement for [bmim]Zn2Cl5/NH3was built, and pressures of [bmim]Zn2Cl5/NH3for T=(323.15-563.15) K were measured by a static method. The experimental data were correlated by a modified UNIFAC model.2. TG scan and DSC scan for [bmim]Zn2Cl5were conducted and heat capacity data were obtained. Mole excess enthalpy data of the binary systems [bmim]Zn2Cl5/NH3for T=(288.15-333.15) K were measured, which were correlated by the NRTL model.3. Based on the heat capacity of [bmim]Zn2Cl5, vapor pressure and excess enthalpy for [bmim]Zn2Cl5/NH3, the investigation and analysis on the thermodynamic performances of [bmim]Zn2Cl5/NH3absorption refrigeration were conducted, which were compared with that of NaSCN/NH3system.From the above mentioned work, we got some conclusions. The solubilities of ammonia in [bmim]Zn2Cl5are higher than that in other ionic liquids, the specific heat capacity of [bmim]Zn2Cl5is small, and the excess enthalpy data of [bmim]Zn2Cl5/NH3are also not very high. All the three parameters are conducive to the improvement of the thermodynamic performances. Through the investigation on the thermodynamic performances of [bmim]Zn2Cl5/NH3system, it is indicated that thermal performances of [bmim]Zn2Cl5/NH3system are better than that of NaSCN/NH3system. Even when the evaporating temperature is low or the condensing temperature and absorption temperature are high, the thermal performances of [bmim]Zn2Cl5/NH3system are still good and the circulation ratios of system are still acceptable. In a word, the working pairs of [bmim]Zn2Cl5/NH3possess great potential for industrial applications and good prospects for commercial development.更多还原