Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-IV-6PRODUCTION OF HYDROGEN FROM THERMO-CATALYTICDECOMPOSITION OF METHANE IN A FLUIDIZED BED REACTORAmmendola P., Chirone R., Ruoppolo G., Russo G.Istituto di Ricerche sulla Combustione – CNR, P.le V. Tecchio, 80 – 80125 Napoli, ItalyPhone: +39 081 7682233 Fax: +39 081 5936936 e-mail: paola.ammendola@irc.cnr.itThe Thermo-Catalytic Decomposition (TCD) of CH 4 is an attractive process for theproduction of H 2 with reduced CO 2 emissions. Main advantages of the TCD processcompared to the conventional technique, i.e. CH 4 steam reforming, are: i) the energyrequirement is less (37.3 kJ/mol H2 ) than steam reforming (68.6 kJ/mol H2 ); ii) due to theabsence of oxidants, no carbon oxides are formed, so CO x -free H 2 is produced; iii) the processis very simple (no water gas shift, CO 2 separation and CO-PROX units). A catalyst would benecessary since the thermal decomposition would require elevated temperatures (above1200°C) [1], even if it deactivates due to produced carbon deposition on its surface.Fluidized bed reactors (FBRs) have been recently indicated [2-5] as an efficient reactorsolution for TCD process to overcome the limits linked to the use of fixed bed reactors,proposed in the past [1]: i) relatively high pressure drops, increased by the accumulation ofcarbon in the bed; ii) impossibility of a continuous operation due to the necessity to unloadcarbon and in turn to regenerate the catalyst. Consequently, new criteria have to be taken intoaccount for catalyst design. In particular, a suitable catalyst should be characterized by a lowpropensity to attrition in addition to the requirements of high thermal stability and conversionefficiency [6]. Ammendola et al. [7] have proposed a suitable copper dispersed on γ-aluminacatalyst in terms of: i) relatively high activity (between that of carbon and Ni catalysts, mainlystudied in literature); ii) high operative temperature (up to 1000°C); iii) relatively highmechanical resistance to attrition.In the present study the TCD of CH 4 has been investigated in a laboratory scale bubblingFBR. The experimental apparatus is reported in the Figure. It consists of a 2.6 cm ID stainlesssteel reactor, equipped with a gauze type gas distributor, an electrical oven surrounding thereactor employed to heat up the reactor at the reaction temperature and to provide enough heatfor CH 4 decomposition, a device for collecting fine particles (> 300nm) escaping from thereactor in the exit gases. Temperature and pressure drops were measured by means ofthermocouples horizontally inserted in the reactor and pressure transducers respectively. Theinlet and outlet streams were analyzed by on line continuous analyzers for CO, CO 2 , CH 4 andH 2 .150