CN-115482885-B - Binary vapor-liquid phase balance prediction method and device

CN115482885BCN 115482885 BCN115482885 BCN 115482885BCN-115482885-B

Abstract

The invention discloses a binary vapor-liquid phase equilibrium prediction method and a binary vapor-liquid phase equilibrium prediction device, wherein the method comprises the steps of decomposing gas molecules to be predicted into a plurality of groups; calculating the proportion parameter of each group in the gas molecules to be predicted, calculating to obtain a binary interaction parameter according to the proportion parameter, establishing a binary phase diagram according to the binary interaction parameter, and predicting the gas-liquid phase balance state according to the binary phase diagram. According to the embodiment of the invention, the groups are obtained by decomposing gas molecules, the binary interaction parameters are established according to the proportion parameters of the groups, so that a great amount of manpower, material resources and time consumed by experiments are avoided to establish the binary interaction parameters, the calculated amount of gas-liquid phase balance analysis is reduced, in addition, the gas-liquid phase balance can be accurately determined through the binary interaction parameters, and the prediction is performed through analysis of the binary phase diagram, thereby improving the accuracy.

Inventors

TANG NIAN
SUN DONGWEI
LI XINGWEN
LI LI
ZHANG BOYA
YAO YUYANG

Assignees

广东电网有限责任公司
广东电网有限责任公司电力科学研究院

Dates

Publication Date: 20260512
Application Date: 20220930

Claims (6)

1. A binary vapor-liquid phase equilibrium prediction method is characterized by comprising the following steps: decomposing the gas molecules to be predicted into a plurality of groups; Calculating the proportion parameter of each group in the gas molecules to be predicted; According to the proportion parameters, calculating to obtain binary interaction parameters; establishing a binary phase diagram according to the binary interaction parameters, and predicting a gas-liquid phase balance state according to the binary phase diagram; the binary interaction parameters are calculated according to the proportion parameters, and specifically: Establishing an excessive free energy mixing rule, and calculating to obtain mixing rule parameters according to the proportion parameters; calculating to obtain cohesive parameters according to gas parameters, wherein the gas parameters comprise critical temperature, critical pressure and eccentric factors; Establishing a binary interaction parameter according to the mixing rule parameter and the cohesion parameter; The method comprises the steps of establishing an excessive free energy mixing rule, and calculating to obtain mixing rule parameters according to the proportion parameters, wherein the mixing rule parameters are specifically as follows: Wherein the excess free energy mixing rule is van laar excess free energy mixing rule; establishing van laar excess free energy mixing rules according to a PR state equation and van laar molar excess free energy models; According to the proportion parameters, solving to obtain the mixing rule parameters of the van laar excessive free energy mixing rule; The expression of the binary interaction parameter is: ; Wherein, the For the parameters of the mixing rule to be described, And As a first cohesive parameter, the first cohesive parameter, And Is the second cohesive parameter.
2. The binary vapor-liquid phase equilibrium prediction method according to claim 1, wherein the decomposing of the gas molecules to be predicted into a plurality of groups is specifically: and decomposing the gas molecules to be predicted into a plurality of groups according to the group division principle of the gas molecular structure by the group contribution method.
3. The binary vapor-liquid phase equilibrium prediction method according to claim 1, wherein the calculating a ratio parameter of each group to the gas molecule to be predicted specifically includes: wherein the ratio parameter is an alpha parameter; And calculating the alpha parameter of each group accounting for the gas molecule to be predicted, wherein the alpha parameter is more than or equal to 0 and less than or equal to 1, and the sum of the alpha parameters of the groups of the gas molecule to be predicted is 1.
4. The binary vapor-liquid phase equilibrium prediction method of claim 1, wherein the expression of the mixing rule parameter is: ; Wherein, the And As a parameter of the interaction of the groups, Is the total amount of different groups defined by the group contribution method, For the currently calculated temperature, And Respectively are radicals Occupying molecules And molecules Is used for the control of the alpha parameter of (c), And Respectively are radicals Occupying molecules And molecules Alpha parameter of (c).
5. The method for binary vapor-liquid phase equilibrium prediction according to claim 1, wherein the cohesion parameters include a first cohesion parameter and a second cohesion parameter; wherein the expression of the first cohesive parameter is: ; Wherein, the For the critical temperature of the gas to be predicted, For said critical pressure of the gas to be predicted, Is an adjustable parameter; The expression for the second cohesive parameter is: 。
6. the binary vapor-liquid phase balance prediction device is characterized by comprising a decomposition module, a first calculation module, a second calculation module and a prediction module; the decomposition module is used for decomposing gas molecules to be predicted into a plurality of groups; The first calculation module is used for calculating the proportion parameter of each group in the gas molecules to be predicted; the second calculation module is used for calculating and obtaining binary interaction parameters according to the proportion parameters; the prediction module is used for establishing a binary phase diagram according to the binary interaction parameters and predicting a gas-liquid phase balance state according to the binary phase diagram; The second calculation module comprises a first parameter calculation unit, a second parameter calculation unit and a parameter establishment unit; The first parameter calculation unit is used for establishing an excessive free energy mixing rule and calculating to obtain mixing rule parameters according to the proportion parameters; The second parameter calculation unit is used for calculating cohesive parameters according to gas parameters, wherein the gas parameters comprise critical temperature, critical pressure and eccentric factors; the parameter establishing unit is used for establishing binary interaction parameters according to the mixing rule parameters and the cohesion parameters; The first parameter calculation unit comprises a rule establishment subunit and a parameter calculation subunit, wherein the excess free energy mixing rule is van laar excess free energy mixing rule, the rule establishment subunit is used for establishing van laar excess free energy mixing rule according to a PR state equation and a van laar molar excess free energy model, and the parameter calculation subunit is used for solving and obtaining the mixing rule parameter of the van laar excess free energy mixing rule according to the proportion parameter; The expression of the binary interaction parameter is: ; Wherein, the For the parameters of the mixing rule to be described, And As a first cohesive parameter, the first cohesive parameter, And Is the second cohesive parameter.

Description

Binary vapor-liquid phase balance prediction method and device Technical Field The invention relates to the technical field of phase balance test, in particular to a binary vapor-liquid phase balance prediction method and device. Background Due to the limitation of environmental factors, the requirements on the refrigerant in the refrigeration system are higher and higher, wherein the gas-liquid phase balance data are used for judging the gas-liquid phase balance property of binary gas so as to reflect the relation among the pressure, the temperature and the component concentration of the working medium. Since the performance of a system using a refrigerant is highly dependent on the choice of working fluid and designing ORC (Organic RANKINE CYC L E) and HP (Heat Pump) systems requires knowledge of the thermophysical properties of the working fluid, the predictions can be used to guide the system how to choose the working fluid and how to design the system. The gas-liquid phase balance data has great significance for engineering application and design of the refrigerant, and is an indispensable component in thermodynamics, so that the acquisition of the physical property data provides basic data for guiding the operation and design of a heat pump and a refrigeration system. At present, experimental measurement is still a main method for obtaining gas-liquid phase balance data at home and abroad, but the measurement of gas-liquid phase balance needs to consume a great deal of manpower, material resources and time. At the same time, the new chemicals are updated faster and faster, the number of the mixtures in the chemical industry is tens of thousands, and experimental data cannot be provided for each mixture all the time, and the experimental data can not meet the requirements of engineering application. In order to solve the problem in the prior art, mainly molecular dynamics and Monte Carlo (Monte Carlo) simulation are adopted, and a computer molecular simulation method for obtaining the macroscopic thermodynamic property of a system by researching the microscopic property of the system is generally required to establish an accurate molecular force field and combine certain assumption conditions to simplify a calculation model. However, the molecular model has the defects of high dependence on a molecular force field, large calculation amount and poor accuracy for a complex mixed system. Disclosure of Invention The invention provides a binary vapor-liquid phase balance prediction method and a binary vapor-liquid phase balance prediction device, which are used for solving the technical problems of large calculated amount and poor accuracy in the process of analyzing vapor-liquid phase balance in the prior art. In order to solve the above technical problems, an embodiment of the present invention provides a binary vapor-liquid phase equilibrium prediction method, including: decomposing the gas molecules to be predicted into a plurality of groups; Calculating the proportion parameter of each group in the gas molecules to be predicted; According to the proportion parameters, calculating to obtain binary interaction parameters; And establishing a binary phase diagram according to the binary interaction parameters, and predicting the gas-liquid phase balance state according to the binary phase diagram. The method obtains the groups by decomposing gas molecules, establishes the binary interaction parameters according to the proportion parameters of the groups, avoids using more experimental data to establish the binary interaction parameters, reduces the calculated amount of analysis of gas-liquid phase equilibrium, can accurately determine the gas-liquid phase equilibrium by the binary interaction parameters, predicts by analyzing the binary phase diagram, and improves the accuracy. Further, the method comprises the steps of decomposing the gas molecules to be predicted into a plurality of groups, specifically: and decomposing the gas molecules to be predicted into a plurality of groups according to the group division principle of the gas molecular structure by the group contribution method. Further, the calculating the ratio parameter of each group to the gas molecule to be predicted specifically includes: wherein the ratio parameter is an alpha parameter; And calculating the alpha parameter of each group accounting for the gas molecule to be predicted, wherein the alpha parameter is more than or equal to 0 and less than or equal to 1, and the sum of the alpha parameters of the groups of the gas molecule to be predicted is 1. According to the method, after the gas molecules to be predicted are divided into different groups according to the group division principle, the proportion of the groups to the gas molecules to be predicted is obtained by obtaining the alpha parameters of the groups, so that the method is used for establishing binary interaction parameters, reducing the use of other experimental paramete