OP-II-3

PP-III-2110080CS-18CS-34CHZ30CHZ80100%80%Ethene Propene Butenes Coke content, %19.0026.5565X CH3Cl , %604020S olefins , %60%40%34.6633.6616.2122.164Coke content, %3200 30 60 90 120 150 180 210 240 270time on stream, min20%0%5.897.171.87 3.682.17 2.17CS-18 CS-34 CHZ30 CHZ8010Figure 1: Evolution with time on stream of theconversion of MeCl using different catalysts.350 °C; 5.8 (g of catalyst) h (mol CH 2 ) –1 ; feed,pure MeCl; time on stream, 4 h.Figure 2: Individual olefin selectivity at zero timeon stream and coke content deposited on thecatalysts. 350 °C; space time, 5.8 (g of catalyst) h(mol CH 2 ) –1 ; feed, pure MeCl; time on stream, 4h.Catalyst of HZSM-5 zeolite (SiO 2 /Al 2 O 3 =80) presents a very slow deactivation in4h in the MeCl (63 % of conversion calculated on a CH 2 basis) (Figure 1). This is aconsequence of the moderate acid strength (Table 1) and low coke deposition in thepores of the catalyst (Figure 2). On the other hand, catalyst of HZSM-5 (SiO 2 /Al 2 O 3=30) zeolite has a higher deactivation. This might be as a consequence of the higheracidity strength of the acid sites (Table 1). The severe shape selectivity of the SAPO-18 and SAPO-34 is decisive for the rapid deactivation (blockage of pores) by cokedeposition of the corresponding catalyst.Regarding olefin selectivity, the propylene is the major product for SAPO-18(35 %) and SAPO-34 (34 %), whereas butenes are the major olefin for catalystsbased on HZSM-5 zeolites (Figure 2).Consequently, the catalytic transformation of methane (via chloromethane) is aninteresting complementary route for the MTO process, in order to obtain light olefinson catalyst of HZSM-5 zeolite with a moderate acid strength.References[1]. Naccache C.M., Mériaudeau P., Sapaly G., Van Tiep L., Ben Taârit Y. J. Catal. 2002 205 217-220.[2]. Noronha L. A., Falabella Souza-Aguiar E., Mota C.J.A. Catal. Today 2005 101 9-13.[3]. Svelle S., Aravinthan S., Bjørgen M., Lillerud K., Kolboe S., Dahl M. I., Olsbye U. J. Catal. 2006241 243-254.[4]. Aguayo A. T., Gayubo A. G., Vivanco R., Olazar M. and Bilbao J. Appl. Catal. A. General 2005283 197-207.479