Thermodynamic Properties for Hydrogen Liquefaction and Processing

Introduction

Hydrogen plays a prominent role in all concepts for CO2 mitigation. Technologies for generation and liquefaction of hydrogen need to be scaled up by orders of magnitude. This scale-up has to rely on simulations of innovative processes, which are necessarily based on thermodynamic property models.

Challenges in Current Models

An analysis of the available models indicates that properties of hydrogen are described with one order of magnitude larger uncertainty than properties of well-known fluids. Experience with process-simulation based scale-up shows that these uncertainties will likely result in large additional costs and delays.

Objectives of ThermoPro-pHy

To improve the description of properties of hydrogen and to enable the application of advanced liquefaction concepts, fundamental breakthroughs are required regarding:

1. The metrology of fluids at cryogenic temperatures.
2. Accurate modelling of these complex systems.

ThermoPro-pHy addresses this pioneering scientific work.

Experimental Developments

Experimental equipment will be developed that allows for highly accurate measurements of:

• Density
• Speed of sound

These measurements will be conducted at temperatures down to the triple point of hydrogen (14 K), far below current temperature limits.

Development of Property Models

Property models will be developed that yield a highly accurate and consistent description of arbitrary mixtures of ortho- and parahydrogen for the first time. This will include the effects of the temperature-dependent ortho/para-equilibrium.

Addressing Impurities

Solid phases of impurities affecting large-scale liquefaction processes will be described by models that are consistent with accurate fluid-phase models.

Mixed Fluid Cascade Processes

Measurements and modelling of mixtures of helium, neon, and argon will establish an accurate basis for the application of mixed fluid cascade (MFC) processes for hydrogen liquefaction.

Expected Outcomes

ThermoPro-pHy will result not only in scientific breakthroughs regarding the metrology of fluids and accurate modelling of thermodynamic properties but also in increased accuracy and credibility of process simulations for hydrogen technologies.