Thermodynamic characterization of the ($H_{2}$ + $C_{3}H_{8}$) system significant for the hydrogen economy: Experimental ($p$, $\rho$, $T$) determination and equation-of-state modelling

TL;DR

This study provides detailed experimental density data for hydrogen-propane mixtures across various conditions, compares these with existing equations of state, and applies advanced models to improve understanding for hydrogen energy applications.

Contribution

It offers new experimental ($p$, $ ho$, $T$) data for hydrogen-propane mixtures and evaluates their accuracy against existing equations of state, introducing improved modeling approaches.

Findings

Density deviations within ±0.5% for low propane content

Higher deviations observed for mixtures with more propane at certain conditions

Application of virial and PC-SAFT equations enhances modeling accuracy

Abstract

For the gradual introduction of hydrogen in the energy market, the study of the properties of mixtures of hydrogen with typical components of natural gas (NG) and liquefied petroleum gas (LPG) is of great importance. This work aims to provide accurate experimental ($p$, $\rho$, $T$) data for three hydrogen-propane mixtures with nominal compositions (amount of substance, mol/mol) of (0.95$H_{2}$ + 0.05$C_{3}H_{8}$), (0.90$H_{2}$ + 0.10$C_{3}H_{8}$), and (0.83$H_{2}$ + 0.17$C_{3}H_{8}$), at temperatures of 250, 275, 300, 325, 350, and 375 K, and pressures up to 20 MPa. A single-sinker densimeter was used to determine the density of the mixtures. Experimental density data were compared to the densities calculated from two reference equations of state: the GERG-2008 and the AGA8-DC92. Relative deviations from the GERG-2008 EoS are systematically larger than those from the AGA8-DC92. They are within the $\pm$0.5% band for the mixture with 5% of propane, but deviations are higher than 0.5% for the mixtures with 10% and 17% of propane, especially at low temperatures and high pressures. Finally, the sets of new experimental data have been processed by the application of two different statistical equations of state: the virial equation of state, through the second and third virial coefficients, $B$($T$, $x$) and $C$($T$, $x$), and the PC-SAFT equation of state.