Hydrogen production by direct contact pyrolysis of natural gas

In this paper, we propose the concept of utilizing the heat generated in Generation IV nuclear reactors to produce hydrogen and carbon from methane or natural gas by direct contact pyrolysis, a process that features zero greenhouse gas emissions. Methane or natural gas was bubbled through a bed of either low-melting-point metals (e.g., lead or tin), granular or catalytic materials (e.g., silicon carbide, a-alumina, NiMo/gamma-alumina), or a mechanical mixture of molten metal and solid media. The methane conversions were found to be dependent upon the contact time between the methane and the heat transfer media, as well as on the methane bubble size. The most efficient systems used for the pyrolysis process were found to be the ones in which natural gas was bubbled through Mott porous metal filters, in a bed of either 4-in. Sn + SiC or Sn, with the product stream comprised of almost 80 and 70 vol % of hydrogen at 750degreesC, respectively. The main advantage of this proposed system is the ease of buoyant separation of the generated carbon byproduct from the liquid heat transfer media. These experiments lay the groundwork for developing technical expertise in producing pure hydrogen cost-effectively by utilizing the heat energy contained in the liquid metal coolant in Generation IV nuclear reactors.