Thermodynamic characterization of liquid organic hydrogen carrier for H12-BT/H18-DBT: Experimental (p, ρ, T) studies and theoretical modeling

● Liquid pρT properties of H 12 -BT/H 18 -DBT mixtures were completely investigated. ● Comprehensive influence of various factors on volumetric properties was analyzed. ● Theoretical models were developed to accurately predict thermodynamic properties. ● Practical hydrogen storage capacities of BT/DBT-based LOHCs were further evaluated. Owing to the excellent hydrogen storage capacity and economic viability, BT/DBT-based LOHCs would have an essential contribution to achieve the long-term storage and long-distance transportation of hydrogen. This study mainly focuses on experimental investigation of liquid pρT properties for H 12 -BT/H 18 -DBT to establish the thermodynamic model and evaluate the hydrogen storage performance. Liquid densities have been measured at temperatures from 293.15 K to 453.15 K and pressures up to 20 MPa, which were employed to explore the influence of various factors on volumetric properties. Because of the great weakness of molecular rigidity and π-π interactions, liquid densities of H 2 -rich LOHCs have been observed to be 13% ∼ 15% lower than those of H 2 -lean LOHCs under the identical thermodynamic conditions. Based on these available datasets and Constantinou-Gani method, PC-SAFT EoSs of H 12 -BT/H 18 -DBT have been developed to calculate liquid densities with AAD of less than 0.13% and successfully predict isobaric heat capacities. Furthermore, derived thermodynamic properties and hydrogen storage capacities have been determined by theoretical models, which would be utilized to explore the microscopic interactions, process optimization and compositional screening. With consideration of fundamental requirements for hydrogen storage materials, these results indicate that desirable mole fraction of H 12 -BT for BT/DBT-based LOHCs would be recommended between 0.15 and 0.20 for practical industries.