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PP-III-77INFLUENCE OF DIFFERENT METALLIC AND ACID FUNCTIONS ONDIMETHYL ETHER STEAM REFORMINGVicente J., Remiro A., Valle B., Ereña J., Gayubo A.G.Chemical Engineering Department. University of the Basque Country.P.O. Box 644, 48080 Bilbao, Spain.Tel: 34-94-6015361: Fax: 34-94-6013500: e-mail: jorge.vicente@ehu.esIntroduction. Dimethyl ether steam reforming (DME SR) is currently regarded asa promising process for H 2 production for both present industries and newtechnologies for fuel cells [1]. DME SR comprises two moderately endothermicreactions in series: 1) DME hydrolysis to methanol (MeOH) on an acid function, suchas γ-Al 2 O 3 [2] or zeolites [3]; and 2) MeOH SR on a metallic function, usually basedon Cu [4].This paper studies the influence of different Cu-based functions and acidfunctions on the activity and stability of bifunctional catalysts in the DME SR. Themetallic/acid ratio for maximizing H 2 yield has also been determined.Experimental. The catalysts have been prepared by a wet mixture of the metallicand acid functions. Three Cu-based metal functions have been prepared by coprecipitation,with Cu/Zn/Al atomic ratios of 2/1/0, 1/1/0, 1/1/0.22 A commercialcatalyst (G66) for methanol steam reforming (Cu/Zn/Al = 2.75/1/0.42) has also beenused for comparison. A commercial γ-Al 2 O 3 , a commercial HZSM-5 zeolite(SiO 2 /Al 2 O 3 = 30, denoted Z30) and a HZSM-5 zeolite modified by alkaline treatment(denoted ATZ30) [5] have been used as acid functions. The metallic and acidfunctions have been calcined at 325 and 550 °C, respectively. The properties of thecatalysts have been studied by ICP, N 2 adsorption, NH 3 differential adsorption andTPD, FTIR, TPR and NO 2 chemisorption. DME SR has been carried out in automatedreaction equipment provided with an isothermal fluidized-bed reactor connected onlineto an Agilent 3000 MicroGC. The operating conditions are: space time up to 0.6g catalyst h/g DME , steam/DME/He ratio = 3/1/0.85 and temperature range = 250-400 °C.Results and discussion. Table 1 shows the values of DME conversion and H 2yield at 20 minutes of time-on-stream for the bifunctional catalysts studied. Thecatalysts based on HZSM-5 zeolite allow obtaining the same conversion as thecatalyst based on γ-Al 2 O 3 but at a considerably lower temperature, due to their acidproperties that promote DME hydrolysis to methanol. Consequently, H 2 selectivityand stability of the catalysts are notably improved since the WGS reaction is584