Production of hydrogen from thermo-catalytic decomposition of methane in a fluidized bed reactor

The Thermo-Catalytic Decomposition (TCD) of methane has been investigated in a laboratory scale bubbling fluidized bed reactor using a copper dispersed on ?-alumina as a catalyst. The effects of both total flow rate and amount of catalyst, i.e. contact time, as well as of reaction temperature and CH4 inlet concentration on CH4 to H2 conversion, amount of carbon deposited on the catalyst and deactivation time have been investigated. The relevance of attrition phenomena have been also investigated as a useful way to mechanically regenerate the catalyst, removing the carbon deposited on the external surface of catalytic particles. Samples of bed catalytic particles after TCD tests have been characterized by means of different techniques: (i) elemental analysis to obtain the amount of carbon deposited on the catalyst; (ii) SEM/EDS analysis to determine the morphology of carbon deposited on the catalyst surface; (iii) BET analysis to obtain the surface areas of deactivated catalyst. Different dimensionless groups have been compared in order to quantitatively assess the relative importance of intrinsic kinetics and of intraparticle and interphase (bubbles to emulsion phase and emulsion phase to catalyst particle) diffusional resistances and to highlight the controlling regimes under the various operating conditions.