D2.3 Stability of odorants in hydrogen

This report D2.3 is part of HyDelta work package 2 “Odorization of hydrogen” and describes the long term stability of candidate odorants for hydrogen in a hydrogen gas matrix. Furthermore the current knowledge about the behaviour of odorant and hydrogen in a soil, compared to the behaviour of odorant and natural gas will be summarized. Also the current knowledge about possible de-mixing effects of odorant in hydrogen after a gas leakage will be summarised.

Three candidate odorants, all selected in a previous phase, were tested for chemical stability in an atmosphere of 100 bar hydrogen over a three month test period by gas chromatographic analysis. All odorants THT, Gasodor® S-Free and 2-hexyn, were found to exhibit stable behavior, allowing them to exert their effect for a longer period of time.

In the case of a gas leak from a mixture of an odorant in hydrogen, it behaves like a singular gas cloud and no separation of the odorant and hydrogen occurs. It is possible that the concentration of the mixture in space is not the same everywhere due to stratification, but this effect also applies to natural gas. With regard to the distribution of gas in a room and the smell of a gas leak, odorization of hydrogen is just as effective as odorization of natural gas.

The behavior of an odorant in hydrogen in soil, which is important for examining how a gas leak in the soil behaves, will be reported in the final version of this report in mid-2022.