为了适应节能与环境保护的需求,研究了一种适用于自复叠制冷系统的新型绿色混合制冷工质(R290/R744)的汽液相平衡特性。根据相平衡条件采用PT状态方程结合Van der Waals混合规则推导出该混合制冷工质的相平衡计算式,通过软件编程计算了两种有工程实用意义的相平衡问题,一种是已知混合物压力和液相摩尔分数,计算泡点温度和气相摩尔分数;另一种是已知混合物压力和气相摩尔分数,计算露点温度和液相摩尔分数,并根据计算数据绘制了汽液平衡曲线。数据显示最大相对误差为4.840%,最小相对误差为0.005%。计算结果表明,采用给出的R290/R744混合制冷剂相平衡计算式具有较高的计算精度,从而为采用该混合制冷剂的自复叠制冷循环研究奠定基础。

In order to adapt to the requirements of the energy-saving and environmental protection,the main purpose of this study was to investigate the vapor-liquid equilibrium (VLE) properties of theR290/R744 mixtures.This refrigerant mixture can be used in auto-cascade refrigeration system. For this purpose,the calculation formulas of phase equilibrium of the mixtures were derived using PT state equation and Van der Waals mixing rules based on the phase equilibrium condition.According to the requirements of engineering applications,two phase equilibrium problems were calculated by software programming.One is to calculate the bubble point temperature and mole fraction in vapor phase using the pressure and mole fraction in liquid phase of the mixtures,the other is to solve the dew temperature and mole fraction in liquid phase using the pressure and mole fraction in vapor phase of the mixtures .The VLE graph of the mixtures was also finished.The comparison with references shows that the maximum r

采用汽液双循环平衡釜，在常压（101.3 kPa）下测定了丙酮-丙酮连氮二元组分物系以及部分丙酮-水-丙酮连氮三元组分物系的汽液平衡数据。实验数据经Herington面积积分法检验符合热力学一致性。通过化工过程模拟软件，分别采用 Wilson、NRTL、UNIQUAC 活度系数模型对丙酮-丙酮连氮二元组分物系实验数据进行关联得到模型参数。并对汽液平衡的计算值与实验值进行比较，3种模型都吻合良好，其中由NRTL方程关联得到的计算结果最为适合，平均温度偏差和汽相组成偏差分别为0.0639 K和0.0048。从三元汽液相平衡数据中拟合出了丙酮-丙酮连氮、丙酮-水、水-丙酮连氮之间的 NRTL 方程相互作用参数。为验证数据及其二元相互作用参数的可靠性，利用关联出的丙酮-丙酮连氮模型参数计算出汽相组成与丙酮-丙酮连氮的二元数据比较，二者符合较好。实验和关联的结果为精馏分离丙酮-水-丙酮连氮汽液平衡体系提供了一定的基础数据。

Vapor-liquid equilibrium (VLE) data for acetone-azine binary system and parts of acetone water azine ternary system were determined in an Othmer equilibrium at atmospheric pressure (101.3 kPa). The experimental data was verified by Herington method and were consistent with thermodynamics. The data of acetone-azine binary system were correlated with the NRTL,Wilson and UNIQUAC models by using chemical engineering analogue software. Respectively,all the models were correlated well with the VLE data. NRTL model produced best data,with the average deviations of temperature of 0.0639 K and vapor-phase mole fraction of methanol of 0.0048. The NRTL model was used to correlate the VLE data of the ternary system,and the interaction parameters of acetone-azine,water-azine,and acetone-water were obtained. In order to verify the reliability of the VLE data of the ternary system and these interacting binary parameters,the vapor compositions were calculated and compared with the corresponding experi

研究建立了天然气体系中汽-液两相相平衡理论模型并进行了计算。通过自主研发的热力学计算软件,使用PR方程,针对我国某LNG厂的天然气体系进行了相平衡计算,并做出了天然气的相包络图,为天然气的液化工艺设计提供可靠的数据支持和理论依据。

The computational model of liquid -vapor phase equilibrium in nature gas was established based on PR equation.For the natural gas system of an LNG plant in China , liquid-vapor phase equilibrium of every component in nature gas was calculated , and thephase diagram was drawn and the trends of vapor -liquid phase equilibrium constant k with the change of temperature and pressure were analyzed and summarized.The theoretical model , calculated data and results had important theoretical significance to the basic study of LNG industry in China.

煤制乙二醇过程中产生的副产物1,4-丁二醇对获得高纯度的乙二醇有着重要影响。采用真空精馏方法分离提纯，进行设计计算时，需要乙二醇-1,4-丁二醇汽液平衡数据。为此在6.67 kPa压力下测定了乙二醇-1,4-丁二醇的汽液相平衡数据，并进行了热力学一致性检验，结果表明实验数据符合热力学一致性。分别用Wilson和NRTL模型对实验数据进行关联，发现两个模型误差都不大，均可满足工程设计的需要。

The byproduct, 1,4-butylene glycol from the process of producing glycol by coal, significantly influences the production of highly pure ethylene glycol. The vapor-liquid equilibrium data is necessary in design of separating and purifying ethylene glycol by mean of vacuum distillation. Therefore, the vapor-liquid equilibrium data of ethylene glycol and 1,4-butylene glycol were measured under 6.67 kPa, and thermodynamic consistency test was implemented. The results show good thermodynamic consistency. Wilson and NRTL equations were used to fit the experimental data, separately. Good agreements were obtained for both equations. Thus the parameters of the two equations obtained in this study can meet the needs of engineering design.

采用自制的Rose釜在绝压2 kPa下测定γ-丁内酯-二乙二醇二元系的汽液平衡数据,并对所测得的数据进行热力学一致性检验,结果表明实验数据符合热力学一致性。以汽相组成的误差平方和作为目标函数,分别用Wilson和NRTL方程关联实验数据,得到分子交互作用能量参数,并对汽液平衡计算值与实验值进行比较,发现二者最大偏差为0.0143,平均偏差0.0063。采用溶液浓度三次方程分别对Wilson和NRTL方程进行修正,修正后二者最大偏差0.0094,平均偏差0.0036,明显优于修正前的结果,可满足工程上分离设计的需要。

The vapor-liquid equilibrium (VLE) data of the γ-butyrolactone-diethylene glycol system were measured at 2kPa using a home-made Rose vapor-liquid equilibrium device, and the thermodynamic consistency of the experimental data were examined. The results show that the experimental data are thermodynamically consistent. The VLE data obtained were correlated with Wilson and NRTL equation respectively, and model parameters were determined. Comparison of the experimental data with fitting equation results shows that the maximum deviation and the average absolute deviation are 0.0143 and 0.0063, respectively. A cubic polynomial modification of the Wilson and NRTL equation considering the molar composition of the liquid phase was proposed. The results show that the maximum deviation and the average absolute deviation of the modified equations are 0.0094 and 0.0036, which indicates that the modified models are better for engineering separation design.