Thermophysical Properties of Hydrogen Enriched Natural Gas (21.RP2.0093)

Thermophysical property data for pure hydrogen and its related mixtures are essential to design the process equipment required for production, liquefaction, storage and transport. However, there is a notable lack of accurate data at industrially relevant conditions, especially for hydrogen mixtures above 100 K (transport and utilisation) and for hydrogen with impurities at cryogenic temperatures (liquefaction and storage). These concerns also extend to mixed refrigerants (MRs) that will be used in industrial liquefiers. Furthermore, for the data that are available, significant differences are observed relative to the predictions of thermophysical property models. The scarcity of experimental data makes it extremely difficult to validate or improve model performance. Current models for hydrogen are approximately one order of magnitude less established than those of methane or nitrogen, with large differences (at least 10%) between models, potentially requiring substantial over design to manage uncertainty in operation.

The limitations of thermophysical property models and uncertainties that arise from limited data ultimately increase the uncertainty in the design, for example using typical process simulations and flow sheet calculations tools such as Aspen HYSYS. Moreover, instrumentation and monitoring of hydrogen processes inherently relies on accurate models. For example, metering of mixed-gas flow at moderate and high pressure requires uncertainties in density to be less than 0.5 % for accurate custody transfer. Uncertainty in property calculations can also lead to inefficiencies in design and operation of process equipment (e.g., blade angles in turbo machinery, limiting operational range; design of advanced heat exchangers with very small temperature gradients).

This project will focus on the blending hydrogen into natural gas pipeline networks as a means of delivering hydrogen to markets. Mixing hydrogen into natural gas pipelines requires several considerations regarding the compression of this mixture, the use of the mixture as a fuel (for example, in gas turbines), and the impact of pipeline capacity and transport efficiency. However, there still a need to improve the quality and quantity of data available for hydrogen-natural gas mixtures (such as density, heat capacity, speed of sound, viscosity, phase equilibrium, water-vapour dewpoint, and interfacial tension) to assess the impact of hydrogen addition in various concentrations to a natural gas pipeline.

Partners: INPEX Holdings Australia Pty Ltd, Wood. The University of Western Australia

Project Researchers: Dr Paul Stanwix, Dr Saif Al Ghafri

Duration: 6 months

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