Size control of SAPO-34 crystals and their catalyst lifetime in the methanol-to-olefin reaction

Nishiyama, Norikazu; Kawaguchi, Masumi; Hirota, Yuichiro; Vu, Dung Van; Egashira, Yasuyuki; Ueyama, Korekazu

doi:10.1016/j.apcata.2009.04.044

Cited by 197 publications

(120 citation statements)

References 20 publications

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“…19−22 The short diffusion length in nanoscale catalyst, resulting in the reduction of residence time of reactant and products of MTO reactions, was used to explain the long catalyst lifetime of nanocrystals. 19 The increase in the accessible cages near external surface for the SAPO-34 nanoscale catalyst was proved very helpful in improving the conversion efficiency of the SAPO-34 catalyst in the methanol conversion. 20,22 However, Jang et al found that the smallest nanocrystallites of SAPO-34 (<150 nm) tested in their work had a detrimental effect on the catalyst lifetime due to the severe pore blockage by coke deposited on the external surfaces of the nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

“…23 The SAPO-34 catalysts with different particle size distributions were obtained mainly through fractionation or synthesized with different structure-directing agents (SDAs) in the above-mentioned reports. 16,19,20,23 In the present study, four highly crystalline SAPO-34 catalysts with different crystallite sizes (between 20 nm and 8 μm) were synthesized from the starting gel with the same composition under conventional hydrothermal and microwave-assisted heating conditions, using TEAOH as the sole SDA. Methanol conversion was performed over the synthesized SAPO-34s to investigate the influence of crystallite size on the catalytic performance.…”

Section: Introductionmentioning

confidence: 99%

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Nanosize-Enhanced Lifetime of SAPO-34 Catalysts in Methanol-to-Olefin Reactions

et al. 2013

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In this work, we systematically investigated the size effect of silicoaluminophosphate molecular sieve catalysts SAPO-34 on the catalytic performance of methanol-to-olefin (MTO) reactions. Four highly crystalline SAPO-34 molecular sieves with different crystallite sizes were synthesized under hydrothermal conditions carried out in conventional or microwave ovens with the same starting gel composition using TEAOH as the structure-directing agent. The as-prepared SAPO-34s have similar composition, and their average crystal size can be controlled between 20 nm and 8 μm.Textural properties and chemical environments of framework atoms as well as acid concentration were characterized by N 2 adsorption and NMR measurements. The MTO reactions were carried out over these four SAPO-34 catalysts to study their catalytic performances dependent on the crystal size. The occurrence of catalyst deactivation varied considerably with the crystal size of SAPO-34s. Significantly, the nanosized catalysts, especially the sheetlike SAPO-34 catalyst with 20 nm thickness, exhibited the longest catalyst lifetime and lowest coking rate in MTO reactions. On the basis of the measurement of coke formation and the determination of retained coke species, a scheme is proposed to elucidate the reduction in coke deposition and consequently the remarkably enhanced lifetime on the nanosized SAPO-34 catalysts in methanol conversion.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nanosize-Enhanced Lifetime of SAPO-34 Catalysts in Methanol-to-Olefin Reactions

et al. 2013

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“…It accounts for about 60-65 % of the world's propylene production, with the established refinery FCC process accounting for 30 % and the remainder is produced on purpose using metathesis or propane dehydrogenation [57,76].…”

Section: Introductionmentioning

confidence: 99%

Maximizing propylene production via FCC technology

2015

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This review looks at the main processes available for the production of light olefins with a focus on maximizing the production of propylene. Maximization of propylene production has become the focus of most refineries because it is in high demand and there is a supply shortage from modern steam crackers, which now produce relatively less propylene. The flexibility of the fluid catalytic cracking (FCC) to various reaction conditions makes it possible as one of the means to close the gap between supply and demand. The appropriate modification of the FCC process is accomplished by the synergistic integration of the catalyst, temperature, reaction-residence time, coke make, and hydrocarbon partial pressure. The main constraints for maximum propylene yield are based on having a suitable catalyst, suitable reactor configuration and reaction conditions.

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“…3 SAPO-34 molecular sieve with CHA structure is one of the molecular sieves containing a small pore (pore size of 0.38 nm) composed of 8-membered rings (8 MR) 4 and has attracted much interest not only for fundamental understanding but also for applications including catalysis called 'methanol to olefin' (MTO) process [5][6][7][8][9][10] and selective adsorption/separation.…”

Section: Introductionmentioning

confidence: 99%

“…SAPO-34 is one of the most deeply studied catalysts for MTO process. Generally, a small-sized SAPO-34 is superior to large-sized one in catalysis (including the MTO process), 5,6 especially for steady conversion.…”

mentioning

confidence: 99%

A Facile Synthesis of SAPO-34 Molecular Sieves with Microwave Irradiation in Wide Reaction Conditions

Jun¹,

Lee

Seok³

et al. 2011

Bulletin of the Korean Chemical Society

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Various reaction conditions including temperature, time and type and concentration of templates have been changed in order to facilely synthesize, especially with microwave (MW) heating, SAPO-34 molecular sieves. SAPO-34 molecular sieve can be synthesized rapidly with microwave irradiation from a gel containing tetraethylammonium hydroxide (TEAOH) as a template. However, other several templating molecules lead to SAPO-5 molecular sieve under microwave irradiation even though SAPO-34 is obtained by conventional electric synthesis from the same reactant gels. Moreover, SAPO-34 can be obtained more easily by increasing the TEAOH or silica concentration or by increasing the reaction temperature. SAPO-34 can be obtained within 5 min in a selected condition (high temperature of 210 o C) with microwave heating, which may lead to a continuous production of the important material. SAPO-34 synthesized by microwave irradiation is homogeneous and small in size and shows acidity and a stable performance in the dehydration of methanol and 2-butanol to olefins, suggesting potential applications in acid catalysis.

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Size control of SAPO-34 crystals and their catalyst lifetime in the methanol-to-olefin reaction

Cited by 197 publications

References 20 publications

Nanosize-Enhanced Lifetime of SAPO-34 Catalysts in Methanol-to-Olefin Reactions

Nanosize-Enhanced Lifetime of SAPO-34 Catalysts in Methanol-to-Olefin Reactions

Maximizing propylene production via FCC technology

A Facile Synthesis of SAPO-34 Molecular Sieves with Microwave Irradiation in Wide Reaction Conditions

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