Thermodynamics EOS

Thermodynamics EOS

The figure shows the phase diagram of deuterium-neon at ultracryogenic conditions at 24.60 K (blue), 31.86 K (red) and 34.47 K (black) (to the left) and the phase diagram of hydrogen from the SAFT-VRQ-Mie equation of state developed in the group (to the right).

Equations of state and phase equilibria for bulk and nanoscopic systems 

We develop thermodynamic models and equations of state and combine them with phase and reaction equilibrium calculations to compute phase diagrams of fluid mixtures, solids and hydrates. A precise and consistent thermodynamic description at equilibrium is a prerequisite for subsequent nonequilibrium descriptions.  

In our work on equations of state, we collaborate closely with the Department of Gas Technology at SINTEF Energy Research to develop the open-source thermodynamic package Thermopack

We are concerned with various types of equations of state and chose the most appropriate theory to suit the application. In recent years, we have focused on mixtures relevant for the hydrogen society and CCS. For equations of state relevant for the hydrogen society, we have: 

  • Developed the SAFT-VRQ Mie for fluid mixtures that exhibit strong quantum effects, such as mixtures with hydrogen, helium, deuterium and neon. 

  • Developed quantum corrections for cubic equations of state for mixtures relevant for the hydrogen society. 

In our research on equation of state development, we are particularly interested in thermodynamic perturbation theory, and to develop theories that are built on statistical mechanics and a description of how molecules interact. This represents a bridge from the molecular scale to experimental properties on the macro-scale. 

We develop equations of state and thermodynamic models for nanoscopic systems, where we actively use the theory by Hill. On the nanoscale, we have shown that the equation of state will depend on the variables used to control the small system.