Research And Evaluation Of Estimation Methods For Basic Physical Properties

The basic physical property is a very basic and commonly used physical property in the petrochemical industry.The actual production,process simulation,engineering design,scientific research and processing technology development all require a large amount of accurate and reliable basic physical property.With the continuous development of science and technology and continuous improvement of experimental conditions,more and more physical experimental data have been obtained,and more and more new substances have been synthesized.The speed of obtaining experimental data is far behind the emergence of new substances.Moreover,problems such as the critical properties of some heat-sensitive substances are difficult to obtain from experiments,so the evaluation of physical properties has become a researcher's choice,but the estimation methods are various,different methods have different characteristics,and the accuracy of estimation is very varied.It is of great significance to analyze and evaluate the method of estimating the basic physical properties and provide some suggestions for the selection of basic physical property estimation methods for the chemical industry practitioners.In this paper,the estimation methods of critical properties,normal boiling point,acentric factor,van der Waals area,van der Waals volume,standard enthalpy of formation of ideal gas and standard energy Gibbs energy of formation of ideal gas are summarized.The principle and characteristics of these methods are described in detail.Using computer technology,a group database of 7368 substances and a basic property estimation module have been established.The basic physical properties of the 100 compounds were estimated using these methods in the basic physical property estimation model.The estimated values were compared with the collated reliable reference values,and then the relative error analysis was performed.Finally,a selection suggestion for each basic physical property estimation method was proposed.When estimating the critical temperature,if there is normal boiling point data,Joback method is recommended;otherwise,CG method can be used.When estimating the critical pressure,except for nitrogen-containing compounds and carboxylic acid compounds,it is recommended to use the correlation 2 of the element and chemical bond method.The estimation of the critical pressure of these two types of substances is recommended to use the Lydersen method and the Joback method.When estimating the critical volume,the Lydersen method is recommended.The Joback correction method is recommended when estimating the normal boiling point.The Pitzer method is recommended when estimating the acentric factor.The Bondi method is recommended when estimating the van der Waals area and van der Waals volume.The CG method is recommended when estimating standard enthalpy of formation of ideal gas and standard energy Gibbs energy of formation of ideal gas.By summarizing the basic physical property estimation methods,a systematic understanding of the advantages and disadvantages of the basic physical property estimation method and the range of application can be made,which help to select the estimation method in a targeted way and to obtain more accurate estimated values as much as possible,so that the calculation accuracy was improved.Therefore,the theoretical research on the basic property estimation method has great practical value.