Production of hydrogen and carbon nanofibers by thermal decomposition of methane using metal catalysts in a fluidized bed reactor

Abstract

Thermo catalytic decomposition (TCD) of methane using Ni–Cu–Al catalyst in a pilot scale fluidized bed is studied. The conventional method of catalyst preparation based on co-precipitation is compared versus an easier preparation method based on the fusing of the metallic nitrates. Catalysts prepared by both methods shown similar behavior. Fluidodynamic studies have shown that TCD can be carried out in a fluidized bed reactor without reactor clogging provided that a methane velocity of two times the minimum fluidization velocity is used. This high spacial velocity resulted in a reduction of the fraction of methane converted, but not in the quantity of carbon deposited per gram of catalyst. The optimum gas velocity should be chosen in terms of hydrogen production rates and fluidization quality. A semi-continuous fluidized bed installation has been started up and operated to produce at the scale of 60 l h - 1 of hydrogen and 15 g h - 1 of carbon nanofibers.