Valves of multiple types and sizes are being utilized in a natural gas network. The collective experience on valves for natural gas service is extensive. However, the lack of experience and standardization for valves in gaseous hydrogen service is hindering the progression towards a net zero transition. While ISO 19880-3 is available for gaseous hydrogen fuelling stations, it is designed for a much higher frequency use of valves when compared to future gaseous hydrogen pipeline service, therefore it is necessary to establish a standard for gaseous hydrogen pipeline valves, specifically for future hydrogen export pipelines in diameters ranging from 18" to 42".
Hydrogen embrittlement is a notorious damage mechanism in the oil and gas industry. A common misconception is to expect similar failure behaviour in gaseous hydrogen service as in hydrogen sulphide and other hydrogen charging environments. This is reflected in the valve industry with an excessive approach to the qualification of hydrogen valves. The research and trials show that the future export of gaseous hydrogen will not be nearly as detrimental when compared to hydrogen sulphide. Considering this, material selection, qualification and testing can be done in a flexible manner, effectively reducing the costs and labour in the progress of the hydrogen transition.
The suitability of valves in certain profiles for low-pressure pure and blended hydrogen gas service has been investigated. To achieve this, the existing standards, practices, design codes and regulations are reviewed in this paper and the input of natural gas operators, engineering companies, valve manufacturers and experts has been utilized.
The research and trials done by natural gas operators is starting to reveal that the effect of low-pressure hydrogen gas on valves is negligible and the risks involved due to hydrogen embrittlement were low.
These studies also revealed that hydrogen leaks at 2.3 to 3 times of the leak rates of natural gas from an already leaking valve.[1]
The existing valve standards mainly cover general considerations. Without guidance on the material limits, the manufacturers are being forced to qualify their products for more intense conditions. This creates challenges from both technical and economical aspects in the net zero transition progress. This paper aims to specify these challenges and address possible opportunities for the hydrogen transition progress for valves.
