Hydrogen fuel on its own may be greenhouse-gas [GHG] free, but what’s the point of it all if the production methods produce GHGs like carbon dioxide [CO2]?
One way to produce hydrogen fuel is by steam reformation of natural gas, the main component of which is methane [CH4], itself a GHG about 20x more potent than CO2. Steam reformation converts CH4 into hydrogen [H2] and CO2. CO2 isn’t as potent a GHG as CH4, but the process could still be improved to remove CO2 from the equation. It doesn’t make any sense as a fuel otherwise.
Researchers in Germany at the Karlsruhe Institute of Technology [KIT] have come up with another way to process CH4 with the final products being only H2 and carbon [C]. By bubbling CH4 through a column of molten metal at around 1,800°F [1,000°C], CH4 is completely catalyzed. Hydrogen gas escapes, leaving behind only traces of carbon. Producing hydrogen fuel by this new method could be closer to a completely GHG-free fuel, not counting the energy needed to fire up and maintain the molten metal.
“The liquid-metal bubble column reactor… is filled with liquid metal that is heated up to 1000°C. Fine methane bubbles enter the column through a porous filling at the bottom. These bubbles rise up to the surface. At such high temperatures, the ascending methane bubbles are increasingly decomposed into hydrogen and carbon,” explains Professor Thomas Wetzel.