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Titolo:
The effect of crystal size of SAPO-34 on the selectivity and deactivation of the MTO reaction
Autore:
Chen, D; Moljord, K; Fuglerud, T; Holmen, A;
Indirizzi:
Norwegian Univ Sci & Technol, Dept Ind Chem, N-7034 Trondheim, Norway Norwegian Univ Sci & Technol Trondheim Norway N-7034 4 Trondheim, Norway SINTEF Appl Chem, N-7034 Trondheim, Norway SINTEF Appl Chem Trondheim Norway N-7034 Chem, N-7034 Trondheim, Norway Norsk Hydro AS, Res Ctr, N-3901 Porsgrunn, Norway Norsk Hydro AS Porsgrunn Norway N-3901 Res Ctr, N-3901 Porsgrunn, Norway
Titolo Testata:
MICROPOROUS AND MESOPOROUS MATERIALS
fascicolo: 1-2, volume: 29, anno: 1999,
pagine: 191 - 203
SICI:
1387-1811(199906)29:1-2<191:TEOCSO>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
HYDROCARBON FORMATION; REACTION-MECHANISM; ZEOLITE CATALYST; LIGHT OLEFINS; METHANOL; CONVERSION; ZSM-5;
Keywords:
coke deposition; deactivation; MTO; SAPO-34; shape selectivity;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
28
Recensione:
Indirizzi per estratti:
Indirizzo: Holmen, A Norwegian Univ Sci & Technol, Dept Ind Chem, N-7034 Trondheim, Norway Norwegian Univ Sci & Technol Trondheim Norway N-7034 m, Norway
Citazione:
D. Chen et al., "The effect of crystal size of SAPO-34 on the selectivity and deactivation of the MTO reaction", MICROP M M, 29(1-2), 1999, pp. 191-203

Abstract

The effect of intracrystalline diffusion on the conversion of methanol to olefins (MTO) over SAPO-34 of crystal sizes in the range 0.25-2.5 mu m has been investigated at 425 degrees C in a TEOM (tapered element oscillating microbalance) reactor. The 0.25 mu m crystals resulted in a relatively largeamount of dimethylether (DME) escaping the pores of SAPO-34 before being converted to olefins, hence giving lower olefin yields. The 0.4-0.5 mu m crystals gave the largest capacity of olefin formation. The 2.5 mu m crystals resulted in diffusion limitation in methanol conversion, with lower olefin yields as a result. The coking rates increased with increasing crystal sizeat low coke contents, levelling off at a lower level for the largest crystals than for the smaller crystals at high coke contents. The selectivity todifferent olefins was independent of the crystal size at relatively low coke contents. The selectivity on the fresh catalysts was controlled kinetically, and an effect of transition-state shape selectivity on the selectivityto olefins was induced by coke. The positive effect of coke on the ethene formation was explained in terms of a transition-state shape selectivity mechanism, as the formation of olefins with different sizes went through differently sized intermediates and the reactions with larger intermediates deactivated more quickly. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/07/20 alle ore 21:32:16