Hydrogen Pipelines by Teknos

EUROPIPE pipes internally lined with epoxy flow coat — ready for 100% hydrogen.

It was previously confirmed that EUROPIPE’s L485 (X70) pipes are an excellent choice for future hydrogen pipelines designed to ASME B31.12; tests showed the steel exceeds the properties assumed in the standard in a 100 bar pure-hydrogen atmosphere.

Epoxy-based internal flow coatings provide important, well-recognised benefits during installation and operation of gas pipelines. As part of EUROPIPE’s hydrogen research programme, different flow coatings were tested in pure hydrogen. Recent tests by the Salzgitter Mannesmann Research Company (SZMF) confirmed that EUROPIPE’s pipes internally coated with epoxy-based flow coatings can be used for hydrogen pipelines in a 100 bar pure-hydrogen atmosphere.

The specimens originate from pipes internally lined at Mülheim Pipecoatings (MPC) with epoxy-based flow-coat materials TEKNOPOX 3296-06 (82 vol.-% solids) and TEKNOPOX 3297-00 (97 vol.-% solids) supplied by Teknos, at a coating thickness between 61 μm and 120 μm.

Testing followed API RP 5L2 (resistance to gas blistering) and EN 10301/ISO 15741 (resistance to gas-pressure variations / cyclic testing and hydraulic-pressure blistering) — standards commonly used to qualify internal coatings for non-corrosive gases. The blistering tests are usually run with nitrogen; here hydrogen, which has the smallest molecular diameter, was used to see whether it would affect the coating’s resistance to spontaneous pressure drops (a lack of which can cause blistering, delamination or reduced adhesion).

Specimens were placed in an autoclave and pressurised with hydrogen to 100 bar. For API RP 5L2, pressure was released after 24 hours in under 5 seconds to simulate a very rapid drop; the EN 10301/ISO 15741 method applied 10 pressure-variation cycles, and behaviour under pressure variation in a liquid environment (water saturated with CaCO₃) was also studied. Afterwards, surfaces were examined and adhesion determined to ISO 2409 (cross-cut test).

No blistering was observed and the delamination parameter was ‘0’ for all specimens, confirming excellent adhesion after testing. All specimens behaved very well in pure hydrogen — no blistering, degradation or loss of adhesion. EUROPIPE’s pipes with internal coating applied by Mülheim Pipecoatings are an excellent choice for future hydrogen pipelines.

Mülheim an der Ruhr, January 2022 — Marina Tschirbs (EUROPIPE GmbH); Dr. Markus Betz (Salzgitter Mannesmann Forschung).