INTERNAL PRESSURE AND SOLUBILITY PARAMETER FOR LIQUIDS

Based on a modified van der Waals model, in which the excluded volume is expressed as a linear function of density, the internal pressure and the physical contribution of two - dimensional solubility parameter suggested by Bagley et al. can be expressed as functions of density and a size dependent parameter A. A group contribution method for estimating parameter A and then the solubility parameter has been developed. Average relative deviation of the predicted solubility parameters in comparison will the experimental values for more than sixty liquids including non- polar and polar species as well as those with strong hydrogen bonding is 0.8%. Further correlation with topological indices of molecules makes this method applicable to various isomers of saturated alkanes. Average relative deviation of prediction for 34 saturated alkanes is only 0.6%.     

AN APPARATUS FOR MEASURING THERMAL CONDUCTIVITY OF LIQUIDS UNDER HIGH PRESSURE

We have reported a method for measuring the thermal conductivity of liguids un-der high pressure previously [1,2].Such data are necessary for improving thetechnologies such like processing as acidity,pressure cracking,thermal exploitation ofpetroleum,etc. An apparatus has thus been constructed,as shown schematically in Fig.1,tomeasure the thermal conductivity of liquids under pressure up to 25 MPa and temperatureranging from 150 to 250℃.The thermal conductivity cell is cylindrical in from,35mmin length and 25mm in inner diameter.The sample is poured into the cell through the     

CORRELATION OF DIFFUSION COEFFICIENTS FOR LIQUIDS AND DENSE FLUIDS WITH TEMPERATURE AND PRESSURE

On the basis of the free volume theory and activation energy concept,a fundamental equation whichtakes into account the effects of temperature and pressure has been developed.By introducing differentexpressions for the free volume and activation energy,several equations for fluid diffusion coefficients were derivedaccordingly.With the van der Waals free volume and intermal energy formula,a three-parameter model for fluiddiffusion coeffficients at moderate pressure was obtained.The grand average absolute deviation percent of 345data points (44 systems)for self-and infinite dilute inter-diffusivities is 2.32,against the results of the model ofCohen and Turnbull,4.13.In particular,by means of the modified Carnahan-Starling free volume equation,afour-parameter model with average abosolute deviation percent 2.64(30 systems,644 data points)for theestimation of dense fluid inter-and self-diffusivities at high pressures and in supercritical conditions was derived.The derived model is superior to the method of L     

ESTIMATION OF THEMAL PRESSURE COEFFICIENTS FOR LIQUIDS BASED ON THE LAW OF CORRESPONDING STATE

1 INTRODUCTIONThe p-V-T relation of liquids can be represented not only by equations of state,but alsoby the following three partial differentials: α=(V/T)_p/V (1) β=-(V/p)_T/V (2) γ=(p/T)_V (3)Where p,V and T denote the pressure,volume and temperature of liquids;α,βand γ are thethermal expansion,isothermal compressibility and thermal pressure coefficient,respectively. Since the densities of liquids at various temperature and constant pressure can easily bemeasured by experiments,values of α can be obtained easily.If the values of.γ can beestimated,then values of β can be acquired from the following equation:     

A UNIFIED VISCOSITY MODEL FOR HYDROCARBON GASES AND LIQUIDS BASED ON TRANSPoSED PATEL-TEJA EQUATION OF STATE

A unified model for predicting high-pressure viscosities of both hydrocarbon gases and liquids was developed,which is based on the similarity between P-V-T and T-μ-P plots and Patel-Teja equation of state.The characteristic feature of this new model is its capability of describing the continuous variation of fluid viscosity throughciritical region.The pure component parameters are generalized into functions of reduced temperature,reducedpressure,acentric factor and molecular weight.The overall average absolute deviation of predicted viscositiesof 20 pure hydrocarbon fluids(a total of 1941 data points)is 8.7%.     

LONGITUDINAL DISPERSION IN RECTILINEAR FLOW OF DILUTE POLYMERIC LIQUIDS: LIKELY ROLE OF STRESS-INDUCED MIGRATION†

The likely role of stress-induced macromolecular migration in interpreting certain anomalous observations in longitudinal dispersion is discussed. In majority of the cases considered, the migration phenomenon affords an explanation for such behaviour, although in some instances, the operational regime for the dispersion process can itself explain the anomalies.

In those cases, where stress-induced migration could be a contributory factor, a semi-quantitative discussion based on our current understanding of the phenomenon is presented. Such a development, though rather simplistic in nature, enables (at least) a semi-quantitative elucidation of the pertinent variables which may affect the longitudinal dispersion processes involving polymeric media