含新型制冷工质HFO-1234yf的混合物的气液相平衡研究

发布时间：2018-05-15 12:57

本文选题：HFO-1234yf + 替代工质　；参考：《中国科学技术大学》2015年博士论文

【摘要】：氢氟烃(HFCs)和烷烃(HCs)臭氧耗减潜能值(ODP)为0,不破坏臭氧层,是很有前景的替代工质。但是大多数的HFCs具有较高的全球变暖的潜能值(GWP)和大气寿命长的缺点,根据欧盟F-gas法规规定,高GWP的含氟工质开始被限制在新设备中使用。而HCs又具有易燃易爆的危险。因此寻找新型绿色环保的替代工质迫在眉睫。近年,霍尼韦尔和杜邦公司联合推出了一种新型制冷剂,2,3,3,3-四氟丙烯(HFO-1234yf),其GWP1, ODP为0,以及非常短暂的大气寿命(0.029年),被视为很有前景的环保替代工质。但是其较低的汽化潜热值以及微可燃性成了它单独使用的障碍。由于很难找到既环保又拥有优异制冷性能的纯工质,而混合工质通过不同的组分的配比有望找到合适的替代工质。混合工质的热力学性能优劣是其能否被利用的主要因素,其中气液相平衡(VLE)数据更是系统循环热力学分析的基本参数。目前,实验测量是获得气液相平衡数据最准确的方法,因此建立一套高精度测量混合工质VLE性质的实验装置,是非常有必要的。本文在已有制冷工质PVT实验测量系统的基础上,添加了混合工质循环取样系统、摩尔分数测量系统和空气恒温系统,改进成高精度气液相平衡实验装置。通过对HFC-134a/HFC-227ea二元混合工质气液相平衡的实验测量,并与文献对比,证明了本实验装置测量精度高,运行稳定可靠。利用搭建好的实验装置,对含有新型制冷工质HFO-1234yf的二元及三元混合工质气液相平衡性质进行实验研究。测量了HFC-143a/HFO-1234yf、 HFO-1234yf/HFC-152a、HFO-1234yf/HFC-227ea、HFO-1234yf/HFC-600a、HFC-161/HFO-1234yf等二元混合工质以及TFC-134a/HFO-1234yf/HC-600a三元混合工质的气液相平衡性质。得到的实验数据结合Peng-Robinson(PR)方程和van-der-Waals(vdW)混合法则进行关联计算,得到其二元相互作用系数,并证明了PR方程结合vdW混合法则,适用于含HFO-1234yf I的气液相平衡性质计算。课题组之前针对10种HFC与3种HC的二元交互系数建立的差值模型,作者在这13种工质的基础上加入了HFC-161和HFC-134,并引入了临界点参数和偏心因子对其进行改进,得到交互加权差值模型。交互加权差值模型计算精度要高于差值模型。收集了一些HFO-1234yf/HFC的VLE数据,并关联得到其二元相互作用系数。将交互加权差值模型推广至HFO-1234yf,发现HFO-1234yf/HFC推算精度满足工程需求,HFO-1234yf/HC推算偏差较大。考虑到碳碳双键的影响,对HFO-1234yf与HC体系的相互作用系数作了修正,修正后推算精度能更好的满足工程需求。利用交互加权差值模型对含HFO、HFC、HC的二元混合共沸点进行推算。针对HFO/HC和HFC/HC体系一共39组混合物进行研究,结果表明39组混合物中有30组具有明显共沸点,9组没有共沸点。将交互加权差值模型应用到三元混合物的气液相平衡推算,推算结果与文献给出的五组、作者自行测量的一组以及制冷热物性数据库软件REFPROP提供的12组三元混合物进行比较。除了HC-290/HC-600a/HFC-32推算压力偏大在8.05%,其他三元混合工质的推算压力偏差都小于2%,而气相组分的平均偏差也大多在0.01内。说明该模型能用于推算三元混合物的气液相平衡性质。使用交互加权差值模型对三元混合工质的共沸性质进行推算。研究由16种纯工质匹配组合成的三元混合工质。研究的三元混合工质只针对组成该混合物的三种工质两两之间构成的二元混合物是共沸或近共沸的,符合此条件的一共有53种。结果表明,有三组三元混合工质存在明显共沸性质。其中HFC-32/HFC-125/HFC-143a三元混合工质在温度低于220K时才出现共沸点,这个结果与文献描述基本一致,表明推算结果具有很强的指导意义。
[Abstract]:The ozone depletion potential (ODP) of hydrofluorocarbons (HFCs) and alkanes (HCs) is 0. It is a promising substitute for ozone layer without destroying the ozone layer. However, most HFCs has the disadvantages of high global warming potential (GWP) and long atmospheric life. According to EU F-gas regulation, high GWP fluorochemicals are started to be used in new equipment. And HCs It is also in danger of flammable and explosive. Therefore, it is imminent to find a new green alternative. In recent years, Honeywell and DuPont Co have jointly launched a new refrigerant, 2,3,3,3- tetrafluoropropene (HFO-1234yf), its GWP1, ODP is 0, and a very short atmosphere life (0.029 years), which is considered as a promising alternative to environmental protection. However, its lower vaporization latent heat and its micro flammability become obstacles to its use alone.
Because it is difficult to find the pure refrigerant with both environmental protection and excellent refrigeration performance, the mixture is expected to find a suitable substitute by the ratio of different components. The thermodynamic performance of the mixture is the main factor for its utilization, and the gas liquid equilibrium (VLE) data is the basic parameter of the thermodynamic analysis of the system cycle. At present, the experimental measurement is the most accurate method to obtain the gas liquid phase equilibrium data. Therefore, it is very necessary to establish a set of high precision experimental device for measuring the VLE properties of the mixed refrigerant.
On the basis of the existing PVT experimental measurement system of refrigerant refrigerants, the mixed refrigerant circulation sampling system, the mole fraction measurement system and the air constant temperature system are added to improve the high precision gas-liquid equilibrium experimental device. Through the experimental measurement of the gas-liquid equilibrium of the HFC-134a/HFC-227ea two element mixture, it is proved by comparison with the literature. The measuring precision is high and the operation is stable and reliable.
The experimental study on the gas-liquid equilibrium properties of two and three elements mixed refrigerants with a new refrigerant HFO-1234yf was carried out by a set of experimental equipment. The two element mixed refrigerants, such as HFC-143a/HFO-1234yf, HFO-1234yf/HFC-152a, HFO-1234yf/HFC-227ea, HFO-1234yf/HFC-600a, HFC-161/ HFO-1234yf, and so on were measured. The gas-liquid equilibrium properties of the 0A three element mixture are obtained by the experimental data combined with the Peng-Robinson (PR) Fang Chenghe van-der-Waals (vdW) mixing rule, and the binary interaction coefficient is obtained. It is proved that the PR equation is combined with the vdW mixing rule and is suitable for the calculation of the gas-liquid equilibrium properties containing HFO-1234yf I.
Before the task group set up the difference model of 10 HFC and 3 kinds of HC, the author added HFC-161 and HFC-134 on the basis of these 13 types of working fluids, and introduced the critical point parameter and eccentricity factor to improve it, and got the interactive weighted difference model. The calculation precision of the interactive weighted difference model was higher than the difference model. Some HFO-1234yf/HFC VLE data are obtained, and their binary interaction coefficients are correlated. The interaction weighted difference model is extended to HFO-1234yf. It is found that the precision of HFO-1234yf/HFC calculation satisfies the engineering requirement, and the deviation of HFO-1234yf/HC calculation is large. Considering the effect of carbon carbon double bonds, the interaction coefficient of HFO-1234yf and HC system is amended, The revised calculation accuracy can better meet the engineering requirements.
The two element mixed azeotrope containing HFO, HFC and HC was calculated by using the interactive weighted difference model. A total of 39 groups of mixtures in the HFO/HC and HFC/HC systems were studied. The results showed that there were 30 groups of obvious azeotrope in the 39 groups and the 9 groups had no azeotrope.
The interaction weighted difference model is applied to the calculation of the gas-liquid equilibrium of the three element mixture. The calculated results are compared with the five groups given by the literature, and compared with the 12 groups of three yuan mixture provided by the author, as well as the refrigerating thermal physical database software REFPROP. In addition to the HC-290/HC-600a/ HFC-32 calculation, the pressure is 8.05%, and the other three yuan mixture is mixed. The calculated pressure deviations of the working fluid are less than 2% and the average deviation of the gas component is mostly within 0.01. It shows that the model can be used to calculate the gas-liquid equilibrium properties of the three element mixture.
An interaction weighted difference model is used to calculate the azeotropic properties of the three element mixed refrigerants. A mixture of three elements composed of 16 kinds of pure refrigerants is studied. The study's three element mixture is only for the azeotrope or near azeotrope composed of three components of the three refrigerant consisting of the mixture, which is 53 of this condition. The results show that there are obvious azeotropic properties of three groups of three element mixed refrigerants. The azeotrope of HFC-32/HFC-125/HFC-143a three element mixture occurs when the temperature is lower than 220K. This result is basically consistent with the literature description, indicating that the calculated results are of great guiding significance.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB61

【参考文献】