A generalized technique to obtain pure component parameters for two-parameter equations of state

1985 ◽  
Vol 22 (1) ◽  
pp. 77-88 ◽  
Author(s):  
A.Z. Panagiotopoulos ◽  
S.K. Kumar
Keyword(s):  
Equations Of State ◽  
Pure Component ◽  
Two Parameter

scholarly journals A New Method to Calculate the Pure Component Parameters of Any Two-Parameter Equation of State

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
Isam H. Aljundi
Keyword(s):  
Equation Of State ◽  
Equations Of State ◽  
Saturated Vapor ◽  
Pure Component ◽  
New Method ◽  
Average Deviation ◽  
Cubic Equation ◽  
Parameter Equation ◽  
Temperature Dependences ◽  
Two Parameter

Reliable equations of state are very important in the design of refrigeration cycles, since thermodynamic properties can be calculated by simple differentiation. In this paper, a new method to calculate the parameters of any two-parameter equation of state is presented. The method is based on the use of Clapeyron equation and the experimental PVT data. This method was tested on a newly developed cubic equation of state and proved to be simple and fast. Results showed orders of magnitude enhancement in prediction of the saturated vapor pressure even near the critical region. The Percent Absolute Average Deviation (%AAD) was always less than 0.1 in the studied cases. It also showed that the parameters calculated using the original equation deviate strongly from the “experimental” values as the temperature decreases below the critical point. This method can be used to redefine the temperature dependences of these parameters and develop new mixing rules for the mixtures.

scholarly journals Application of PC-SAFT and cubic equations of state for the correlation of solubility of some pharmaceutical and statin drugs in SC-CO2

2013 ◽  
Vol 19 (3) ◽  
pp. 449-460 ◽  
Author(s):  
El Abdallah ◽  
C. Si-Moussa ◽  
S. Hanini ◽  
M. Laidi
Keyword(s):  
Experimental Data ◽  
Equations Of State ◽  
Van Der Waals ◽  
Energy Parameter ◽  
Pure Component ◽  
Binary Interaction ◽  
Statistical Associating Fluid Theory ◽  
Binary Interaction Parameters ◽  
Fluid Theory ◽  
Statin Drugs

In this work, the solubilities of some anti-inflammatory (nabumetone, phenylbutazone and salicylamide) and statin drugs (fluvastatin, atorvastatin, lovastatin, simvastatin and rosuvastatin) were correlated using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) with one-parameter mixing rule and commonly used cubic equations of state Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) combining with van-der Waals-1 parameter (VDW1) and van-der Waals-2 parameters (VDW2) mixing rules. The experimental data for studied compounds were taken from literature at temperature and pressure in ranges (308-348 K) and (100-360 bar) respectively. The critical properties required for the correlation with PR and SRK were estimated using Gani and Noonalol contribution group methods whereas, PC-SAFT pure-component parameters; segment number (m), segment diameter (?) and energy parameter (?/k) have been estimated by tihic?s group contribution method for nabumetone. For phenylbutazone and salicylamide those parameters were determined using a linear correlation. For statin drugs, PC-SAFT parameters were fitted to solubility data, and binary interaction parameters (kij and lij) have been obtained by fitting the experimental data. The result was found to be in good agreement with the experimental data and showed that PC-SAFT approach can be used to model solid-SCF equilibrium with better correlation accuracy than cubic equations of state.

Excess volumes and excess enthalpies of the mixtures tetrachloromethane + cycloalkane and trichloromethane + cycloalkane: Calculation in terms of equations of state of the van der Waals type

1984 ◽  
Vol 49 (11) ◽  
pp. 2446-2457
Author(s):  
Ivan Cibulka ◽  
Robert Holub
Keyword(s):  
Equations Of State ◽  
Van Der Waals ◽  
Pure Component ◽  
Excess Volumes ◽  
Excess Functions ◽  
Excess Enthalpies ◽  
Fluid Approximation ◽  
Flory Theory ◽  
Derivatives Of ◽  
Critical Constants

The excess volumes and excess enthalpies for equimolar compositions and a temperature of 298.15 K for the binary liquid mixture of tetrachloromethane and trichloromethane with cyclopentane, cyclohexane and cyclooctane were calculated in terms of equations of state of the van der Waals type, the Redlich-Kwong equation of state and an equation following from the Flory theory. The pure-component parameters were evaluated in three different ways. The equations of state with pure-component parameters determined from gas-liquid critical constants yielded poor agreement with experiment. The best agreement with experiment was yielded by the Snider-Herrington equation with the pure-component parameters evaluated from molar volumes and thermal pressure coefficients and by the Flory equation. The Frisch equation extended to mixtures by using the van der Waals one-fluid approximation gave a good agreement with experiment in case of mixtures of molecules of approximately the same size. The excess entropies and the values of temperature derivatives of excess functions were as well calculated and compared with available experimental data.

Deviation of the Calculated of Density of Refrigerant Fluids in Both Super and Sub Critical Regions

2011 ◽  
Author(s):  
Neda Mobinipouya
Keyword(s):  
Thermodynamic Properties ◽  
Speed Of Sound ◽  
Equations Of State ◽  
Numerical Procedure ◽  
Corresponding States ◽  
Temperature Range ◽  
Critical Regions ◽  
Two Parameter ◽  
Good Agreement

A numerical procedure has successfully predicted accurate values of thermodynamic properties in seven cubic equations of state (EOS) in predicting thermodynamic properties of nine ozone-safe refrigerants both in super and sub-critical regions. Refrigerants include R22, R32, R123, R124, R125, R134a, R141b, R143, and R152a and equations of state, considered here, are Ihm-Song-Mason (ISM), Peng-Robinson (PR) [2], Redlich-Kwong (RK), Soave-Redlikh-Kwong (SRK), Modified Redlickh-Kwong (MRK), Nasrifar-Moshfeghian (NM), and TCC were shown in this paper. In general, the results are in favor of the preference of TCC and PR EOS over other remaining EOS’s in predicting gas densities of all aforementioned refrigerants in both super and sub critical regions. Typically, PR and SRK are in good agreement with those obtained from recent correlations and speed of sound measurements. Therefore, these two EOS stand over other EOS both in sub and super critical regions. All EOS follow two-parameter principle of corresponding states at T/Tc higher than 8 and lower than 1 except NM EOS. In the temperature range 1<T/Tc<8, PR and SRK still follow above mentioned principle. The same trend has been observed for other refrigerants.

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