Production of hydrogen from gasoline range alkanes with reduced CO2 emission

In this work we proposed and investigated a new technology using gasoline as a fuel for solid polymer electrolyte fuel cell through the decomposition of gasoline range alkanes into hydrogen and carbon. The method can supply a high purity hydrogen without CO and CO2. The decompositions of various alkanes (CH4, C2H6, C3H8, C4H10, C6H14, and C8H18) have been examined over Ni/fumed silica (Cab–O–Sil) at a temperature of 773 K. Main products were hydrogen and carbon fibers with a low concentration by-product CH4. The number of carbons deposited per one Ni atom after complete deactivation of the catalyst was in the range of 750–1000 depending on the starting alkanes. The selectivity of H2 formation increased as the number of carbon in the molecular structure of alkanes increased. Among C6-alkanes, the H2 selectivity improved as 3-methylpentane (92%) <n-hexane (94%) < cyclohexane (96%), but the C/Ni values were increased in the reverse order. It was concluded that gasoline range alkanes (various C6-alkanes and C8H18) were superior to the light alkanes (<C4) for selective decomposition into hydrogen and carbon. The amount of by-products probably formed due to thermal cracking in the gas phase were negligible compared to that of CH4 during the catalytic decomposition of gasoline range alkanes.