HYDROGEN VALVES
element with the lowest density and diffuses comparatively easily through materials . Pruss says that “ this requires special solutions for spindle and housing seals ”. Pruss advises particular caution because hydrogen is both odourless and tasteless and , depending on the concentration , can react explosively with the ambient air . “ When selecting materials , we therefore take great care to check their suitability for use in terms of hardness values , explosive decompression and ductility ”, the company explains .
Round sealing seats
To enable absolute tightness , müller quadax works with the 4-fold eccentric construction principle for its valves . The butterfly valves have a round sealing seat with a uniform wall thickness all around . “ The design differs significantly from the common triple eccentric designs , which have an elliptical sealing seat ”, the company explains . Material expansions have a homogeneous effect on the entire sealing surface due to high-temperature fluctuations “ and thus ensure optimum sealing tightness ”, the company continues . In addition , the Quadax ® H 2 valve is equipped with a special sealing ring made of a dedicated material that “ functions perfectly even at these extremely low temperatures ”.
Safety valves for hydrogen filling stations
Goetze KG supplies high-pressure safety valves for electrolyser manufacturers as well as safety valves for hydrogen filling stations – because in addition to the energy grid and industry , the focus is also on mobility . Goetze sees an increasing international demand for hydrogen technology and supplies safety valves with up to 1000 bar to Chinese and Spanish plant manufacturers . China is already putting a particular emphasis on this , and the world ’ s largest hydrogen filling station was built in Beijing last year .
A pressure test with hydrogen shows whether the valve complies with limit values and fugitive emissions are minimised . Photo : Hartmann Valves
“ Eight hydrogen fuel pumps are ready to refuel up to 600 vehicles on a daily basis ”, Goetze reports . This is possible thanks to the large volume of up to five tonnes of production capacity , embedded in a 200,000 square metre hydrogen park .
Demanding technical challenges
The technical requirements for hydrogen filling stations are higher than for conventional ones , emphasises Herose . At these stations , the gas is stored in low-pressure storage tanks at about 20 bar . In car fuel tanks , however , the hydrogen must be compressed considerably more because of the necessary energy density . “ Compressors first compress the gas to 1000 bar and then store it temporarily in highpressure tanks . To prevent the gas from heating up too much during refuelling , it passes through a pre-cooler ”, the company explains . The refuelling process is controlled electronically , and the pressure in the tank is regulated at 700 bar . “ If the pressure drops unexpectedly , the safety valve opens and allows the excess pressure to escape unhindered into the atmosphere .” As hydrogen is thirteen times lighter than air , it escapes upwards and is not dangerous . Valves with the highest safety standards are required for the passage from petrol station storage tanks to car fuel tanks . And how might hydrogen use look in the future ? In Fraunhofer IFF ’ s view , “ systemically integrated hydrogen production ” is a valuable concept . Not only the hydrogen produced during electrolysis would be used , but also oxygen , i . e . for welding processes or for ozonation of sewage treatment plants . “ Problematic micropollutants such as pharmaceuticals , pesticides or cosmetics can be removed from wastewater by adding ozone ”, Fraunhofer IFF explains . Another possible use is in agriculture , where the oxygen could be used for the desulphurisation of biogas plants . These are more uses that also have promising prospects .
Electrolysis
Compressor
Underground storage
Gas network + H 2
H 2 Pipeline
Generation Transport Storage Utilitsation The diagram shows hydrogen ’ s journey from production to use . Diagram : Hartmann Valves .
Industry Chemical / Petrochem Smelting etc .
Refinery
Heat
Mobility
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