Comparison of Equations of State in Thermodynamic Simulation of Multicomponent Natural Gas Using DWSIM

Khairani Yulia; Muhammad Haviz; Adityas Agung Ramandani

doi:10.22437/j-bigme.v6i3.56283

Penulis

Khairani Yulia Department of Chemical Engineering, Faculty of Industrial Technology, "Veteran" University of National Development, Yogyakarta
Muhammad Haviz Department of Chemical Engineering, Lampung University, Lampung, Indonesia
Adityas Agung Ramandani Department of Chemical Engineering and Materials Science, Yuan Ze University, Taiwan

DOI:

https://doi.org/10.22437/j-bigme.v6i3.56283

Kata Kunci:

DWSIM, Equation of State, natural gas, Peng-Robinson, thermodynamic simulation

Abstrak

The selection of a thermodynamic property package strongly affects the prediction of fluid properties in process simulation, particularly for non-ideal multicomponent natural gas systems. This study evaluates the influence of pressure on the compressibility factor (Z), density, heat capacity (Cp), and molar enthalpy of a natural gas mixture using several equations of state (EOS) in DWSIM. The gas mixture consisted of methane (CH₄), carbon dioxide (CO₂), ethane (C₂H₆), and nitrogen (N₂), simulated at 25 °C with pressure variations from 1 to 50 atm. An initial evaluation was performed on several DWSIM property packages to identify stable and relevant models. The analysis focused on five EOS models: Peng-Robinson (PR), Soave-Redlich-Kwong (SRK), Peng-Robinson-Stryjek-Vera 2 (PRSV2-VL), Peng-Robinson/Lee-Kesler (PR/LK), and Peng-Robinson 1978 (PR78). Increasing pressure reduced Z from approximately 0.998 to 0.866 and increased density up to about 46 kg/m³. Heat capacity increased to approximately 2.22 kJ/kg.K, while molar enthalpy became more negative at high pressure. PR and PR78 produced the most consistent predictions, whereas PRSV2-VL and PR/LK showed the largest deviations in Z and molar enthalpy, respectively.