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

PP-V-16SYNGAS PRODUCTION BY PARTIAL OXIDATION OF METHANEOVER Rh/LaMnO 3 HONEYCOMB CATALYSTSG. Landi 1 , P.S. Barbato 2 , G. Russo 1,21 Institute of Researches on Combustion – CNR – P.le Tecchio 80 – 80125 Naples, ITALY –Fax: +39 0815936936 – e-mail: landi@irc.cnr.it2 Dep. of Chem. Eng. – Univ. of Naples Federico II – P.le Tecchio 80 – 80125 Naples, ITALYSyngas is the row material for the production of H 2 and also clean fuels through gas-toliquidprocesses (like methanol and Fischer-Tröpsch syntheses). In order to produce syngasmore efficiently, catalytic partial oxidation (CPO) of methane has received an increasinginterest during last decades [1]. Through CPO syngas can be produced with no energyconsumption, no coke formation and at relatively low temperature, thus avoiding NO xemissions. Although more expensive than Ni-based catalysts, noble metals appear to be veryattractive because of their high activity (allowing the development of processes at shortcontact time) and no coke formation [2]. On precious metal catalysts (especially on Rh) theeffects of the support morphology [3], the addition of oxygen carriers to the support [4] or thenature of the support [5] have been investigated. However, this class of catalysts suffer fromdeactivation due to the formation of hot spots [6], caused by the rapid CH 4 oxidation leadingto H 2 O and CO, as proposed by Lyubovsky et al. [7]. Recently we proposed a bi-functionalRh/LaMnO 3 honeycomb catalyst for CPO of methane [8, 9]; these catalysts showed betterperformances than Rh only catalysts. In this work the effect of Rh loading on catalyticperformance under several operating conditions is presented; moreover, at fixed catalystcomposition, the effects of honeycomb features (cell density and material) have been studied.Rh/LaMnO 3 catalysts have been prepared according to the procedure described elsewhere[8]. The active phase is composed of Rh (0,1% - 1% wt.) and LaMnO 3 (30% wt.).Commercial cordierite and SiC honeycombs (cell density: 200 - 1200 cpsi) were used assubstrates. Catalytic tests were conducted under adiabatic conditions using the experimentalrig described in [8]. The effects of CH 4 /oxidant ratio, oxidant type (air or oxygen), spacevelocity and CO 2 addition were studied.Catalytic tests conducted over samples containing different Rh loading showed thatcatalytic performance slightly increased with increasing noble metal content. As an example,in figure 1 the catalytic performances of bi-functional catalysts (substrate: cordierite, 600cpsi) containing 0,1%, 0,5% and 1% wt. Rh as a function of CH 4 /O 2 ratio are reported.Methane conversion decreases with increasing CH 4 /O 2 ratio for all the samples, but the curvesrelated to different samples are near each other. It appears that activity is directly related tothe amount of Rh, responsible for the reforming activity. Investigating the effects of other487