The value of the critical compressibility factor for the Redlich-Kwong equation of state of gases

1985 ◽  
Vol 62 (2) ◽  
pp. 110 ◽  
Author(s):  
Reino. W. Hakala
Keyword(s):  
Equation Of State ◽  
Compressibility Factor

A Comprehensive Review of Recent Advances in the Estimation of Natural Gas Compressibility Factor

2021 ◽  
Author(s):  
Oluwasegun Cornelious Omobolanle ◽  
Oluwatoyin Olakunle Akinsete
Keyword(s):  
Artificial Intelligence ◽  
Equation Of State ◽  
Compressibility Factor ◽  
Operating Conditions ◽  
Measurement Equation ◽  
Comprehensive Review ◽  
Holistic Understanding ◽  
Deviation Factor ◽  
Gas Compressibility ◽  
Limited Accuracy

Abstract Accurate prediction of gas compressibility factor is essential for the evaluation of gas reserves, custody transfer and design of surface equipment. Gas compressibility factor (Z) also known as gas deviation factor can be evaluated by experimental measurement, equation of state and empirical correlation. However, these methods have been known to be expensive, complex and of limited accuracy owing to the varying operating conditions and the presence of non-hydrocarbon components in the gas stream. Recently, newer correlations with extensive application over wider range of operating conditions and crude mixtures have been developed. Also, artificial intelligence is now being deployed in the evaluation of gas compressibility factor. There is therefore a need for a holistic understanding of gas compressibility factor vis-a-vis the cause-effect relations of deviation. This paper presents a critical review of current understanding and recent efforts in the estimation of gas deviation factor.

A Fast, Accurate Real Gas Equation of State for Fluid Dynamic Analysis Applications

1995 ◽  
Vol 117 (2) ◽  
pp. 277-281 ◽  
Author(s):  
R. H. Aungier
Keyword(s):  
Equation Of State ◽  
Critical Point ◽  
Fluid Dynamic ◽  
Compressibility Factor ◽  
Original Form ◽  
Acentric Factor ◽  
Application Range ◽  
Property Data ◽  
Modified Forms ◽  
Modified Equation

A modified form of the Redlich-Kwong two-parameter equation of state is presented. The modified equation employs the acentric factor and the critical point compressibility factor as additional parameters to improve its accuracy and to extend its application range to include the critical point. This modified equation is as simple as the original form, yet achieves substantially better prediction accuracy, including thermodynamic parameters such as enthalpy and entropy. Results from this equation, the original equation, and three other popular modified forms are compared with gas property data for several compounds to demonstrate its improved accuracy and increased application range. Practical application limits to the other modified forms are identified to guide current users of those methods.

Isentropic Compressible Flow for Non-Ideal Gas Models for a Venturi

2004 ◽  
Vol 126 (2) ◽  
pp. 238-244 ◽  
Author(s):  
Kenneth C. Cornelius ◽  
Kartik Srinivas
Keyword(s):  
Mach Number ◽  
Equation Of State ◽  
Compressible Flow ◽  
Mathematical Formulation ◽  
Compressibility Factor ◽  
Ideal Gas ◽  
Ideal Gas Law ◽  
Thermodynamic Variables ◽  
Analytical Result ◽  
The Ideal

The non-ideal gas equations and mathematical formulation developed in this work using the compressibility factor in the equation of state closely resemble the derivations used for the ideal gas mathematical formulation for a direct comparison of the differences between the ideal versus the non-ideal gas law. The local Mach number is defined for the non-ideal gas. The plenum total variables used in compressible flow are expressed in terms of the local Mach number for the polytrope and Rayleigh models. A power law relationship is derived between the thermodynamic variables that allow an analytical result for the mass flow under certain constraints.

scholarly journals The Equation of State of Biogas

2017 ◽  
Vol 65 (2) ◽  
pp. 537-543
Author(s):  
Petr Trávníček ◽  
Tomáš Vítěz ◽  
Tomáš Koutný
Keyword(s):  
Equation Of State ◽  
Theoretical Approach ◽  
Van Der Waals ◽  
Compressibility Factor ◽  
Calculated Data ◽  
State Behavior ◽  
Real Gas ◽  
Van Der Waals Equation ◽  
Geometric Average ◽  
Pure Substances

The presented work deals with a state behavior of real gas, biogas. Theoretical approach was utilized for processing of this work. Compressibility factor was calculated with help of two equation of state – Van der Waals equation and Redlich‑Kwong equation. Constants a and b of both equations were calculated using geometric average of the constants of pure substances. On the basis of calculated data charts showing the dependence of compressibility factor and the pressure were created. These charts were created for temperatures 20 °C and 40 °C. Statistical analyses of data were carried out. The results showed that compressibility factor reached value from 0.997 to 0.97 (20 °C) and from 0.997 to 0.974 (40 °C) in the case Van der Waals equation and in the range of pressure from 100 kPa to 1000 kPa. In the case of Redlich‑Kwong equation these values were from 0.997 to 0.967 (20 °C) and from 0.997 to 0.974 (40 °C) in the same range of pressures.

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