D4.2 Report on results of the validation
- Deliverable D4.2 gathers the results obtained in the different tests performed during the first and second experimental campaigns, carried out in the R&D testing platform built in WP3 at Fundación Hidrógeno Aragón (FHA). This R&D facility aims to reproduce a natural gas transport grid at smaller
scale, where different testing components, materials and equipment are exposed to hydrogen. Three different kinds of tests have been performed:
- Gas tightness tests of representative valves of the natural gas (NG) grid to identify possible leakages when operated with hydrogen. The tested valves have been besides thereafter inspected for hydrogen damage.
- Constant strain tests carried out on API 5L steel specimens’ grades X42 to X70, for hydrogen embrittlement evaluation on representative carbon steels in the grid.
- H2/CH4 gas separation tests with a Pd-based membrane prototype, thinking in potential endusers that demand a high natural gas purity and want to remain being costumers of the gridwhen natural gas comes blended with hydrogen.
The first experimental campaign has consisted in the 20/80 (%/%vol) H2/CH4 blend gas condition, without impurities, at 80 bar for 3000 hours. The tightness of different kind of valves led to hydrogen losses below 1 Nml·h-1. No cracks or other kind of damage was found on parts of the equipment (regulator, flowmeter) exposed to the H2/CH4 blend. C-ring, 4pb and CT-WOL specimens machined from API5L steel pipes grades X42 to X70, did not show cracking or pre-crack growth after testing in the hydrogen blend. Besides, H2/CH4 separation has also been successfully achieved using Pd-based membrane technology, obtaining a high-purity methane stream. The tested elements have shown therefore compatibility to this hydrogen level under the specific conditions considered.
Finally, some preliminary results of the second experimental campaign are also included in this report. Specifically, those corresponding to the gas tightness tests. In this last campaign, the 20/80 (%/%vol) H2/CH4 blend has also been used but including up to 11 ppmv of H2S and 4%mol CO2 as impurities, to check the effect of the most common impurities in NG. It was not possible to assess the tightness of the flanged testing valves because of their manipulation after the first experimental campaign, concluding that any manipulation on this kind of components should be done only by the manufacturer. The tightness of the flanged and screwed couplings and of the screwed testing valves, have also been assessed with positive results. However, a failure found in one screwed ball valve after emptying the platform makes necessary its full characterization to reach better conclusions