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Rethinking the electrolysis process
At the heart of Hystar ’ s patented technology is the operating principle of a PEM electrolyser . Traditionally in PEM electrolysis , water is fed into the anode chamber . By moving the water feed to the cathode side , Hystar has devised a process solution that offers an array of benefits . “ If you find this solution simple , this is because it is simple , beautifully so ,” says Jan .
“ By changing the point of water supply to the cell , we have created conditions allowing us to reduce the membrane thickness by as much as 90 % compared to conventional PEM electrolysers , which is remarkable . Hydrogen crossover to the oxygen-containing anode side is a major concern for all electrolysers , because the combination of the two gasses creates a potentially explosive environment . To prevent this crossover , all other PEM electrolyser manufacturers use a relatively thick membrane . While ensuring safety , however , this has a negative impact on the electrolyser efficiency since a thick membrane creates high electrical resistance . And the higher the resistance across the membrane , the lower the efficiency . Our solution , with a significantly thinner membrane , allows the water to travel from the cathode to the anode side , which creates the necessary conditions for the electrochemical splitting of water into hydrogen and oxygen . And by introducing another unique feature – the blowing of air into the freed-up anode chamber , our patented solution dilutes any crossover hydrogen , thereby eliminating the risk of forming a dangerous gas mixture .”
What is more , the ventilation rate can be adjusted , providing additional safety and operational advantages .
“ For example , a membrane rupture or stack malfunction would normally trigger an emergency shutdown ,” explains Jan . “ In a Hystar system , however , we can immediately increase the air feed to stabilise the electrolyser and allow it to continue running safely until the malfunctioning component can be replaced .”
Scalability
Besides efficiency and safety gains , Hystar ’ s technology provides another crucial advantage : compactness . By using a thinner membrane , Hystar has managed to reduce the size of other system components , making them resemble those originally designed for fuel cells . In doing so , the company can piggyback on the
Current PEM electrolyser Hystar PEM electrolyser
The operating principle of a conventional ( left ) and Hystar ’ s ( right ) PEM electrolyser
Hydrogen Tech World | Issue 7 | December 2022 11