Low carbon process improves production of ultra-pure hydrogen

Now a new method for increasing the yield of ultra-pure hydrogen from cheaper feedstocks such as coal and biomass could help to bring costs down.

Hydrogen is most commonly produced from natural gas in a process known as steam reforming, in which methane is heated in the presence of steam, to convert it into a hydrogen-rich mixture known as synthetic gas, or syngas.

The hydrogen is often then separated from this syngas in a step known as Pressure Swing Adsorbtion (PSA), in which the gas is attracted to a solid surface, or adsorbent, under high pressure.

Reactors that use coal or biomass to produce hydrogen have previously been unable to match the high yields possible with natural gas, according to Dr Hyungwoong Ahn, a senior lecturer in Chemical Engineering at Edinburgh University.

But the new method, developed alongside researchers at Yonsei University, South Korea, can improve their yield, while also capturing carbon emissions.

To produce hydrogen from methane, heat is needed to operate the reactors, said Ahn. To provide this heat, the waste tail-gas from the PSA process is often recycled as fuel for the reactor.