Thermoplastic Materials Compatibility for Hydrogen Service
By Ana Antelava
The use of hydrogen as an energy carrier is expected to play an important role in the transition to a low carbon economy. However, to be as effective and accessible as other energy sources for daily use, it requires a reliable network for delivery, storage, and end-use operations.
There are many polymeric elements used in hydrogen infrastructure. High density polyethylenes, Nylons, polyvinylidene fluorides and polyphenylene sulphides are used as liner materials while Teflon, PEEK, acetal, PFA, Buna-N, and Viton are commonly used sealing materials in valves.
For a reliable and safe operation, it is essential to have polymeric materials that will be stable during service. The degradation of polymers during elevated temperatures and under stress is well known and studied. However, polymer degradation due to the hydrogen exposure is not widely researched.
Currently, the widespread adaptation of hydrogen is inhibited by a potential exposure incompatibility with polymeric materials at high pressures.
For a safe hydrogen economy, it is essential to analyse the effect of hydrogen in combination with environmental and operational conditions such as temperature, pressure, humidity and weathering on pipelines, sealing materials and vessels. This will enable estimation and analysis of the material’s performance and provide understanding of its compatibility with hydrogen over prolonged operational time.
The deeper understanding of material compatibility will allow the industry appropriate selection of materials, to carry out bespoke testing and qualification of materials, which will lead to improved performance, reliability, safety and cost reduction.This technical literature review provides an overview of the polymers used in hydrogen infrastructure, operating conditions in hydrogen storage and hydrogen distribution systems and it reviews the recent studies conducted on polymer materials testing for hydrogen infrastructure, highlighting the knowledge gaps.
Review described the current state of the art in hydrogen transport, storage and service.
Commonly used polymeric materials in hydrogen service have been identified.
Operation conditions used in hydrogen service have been identified and described.
Polymer degradation mechanisms and factors affecting it have been described.
Current test methodologies for evaluation of polymeric materials performance have been presented.