Effect of SAPO-34 molecular sieve morphology on methanol to olefins performance

Wu, Lei; Liu, Ziyu; Xia, Lin; Qiu, Minghuang; Liu, Xu; Zhu, Haojia; Sun, Yahui

doi:10.1016/s1872-2067(12)60575-0

Cited by 27 publications

(13 citation statements)

References 11 publications

(9 reference statements)

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“…2b, the SD has nanosheet-like morphology with an average particle below 200 nm, indicating that the precursor gel at low temperature and short crystallization time can transform to nanosheet-like crystals. This is in agreement with the results reported in the literature (Lei et al 2013). Figure 3 shows the XRD patterns of the SAPO-34 samples prepared by dry gel conversion with different amounts of SAPO-34 SS.…”

Section: Catalytic Performancesupporting

confidence: 91%

Green and efficient dry gel conversion synthesis of SAPO-34 catalyst with plate-like morphology

Wang

et al. 2016

Pet. Sci.

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SAPO-34 catalyst with plate-like morphology was designed and synthesized for the first time, by the dry gel conversion method using cheap triethylamine as a structure-directing agent assisted with seed suspension containing nanosheet-like SAPO-34 seed. The latter played an important role in formation of SAPO-34 (CHA-type) with plate-like morphology. In addition, the yield of the product in the synthesis system containing seed suspension reached 97%, 15% higher than that obtained in the corresponding synthesis system without the seed suspension. Meanwhile, the plate-like SAPO-34 catalysts synthesized by this method exhibited higher selectivity to light olefins and longer lifetime in methanol-to-olefins (MTO) reaction than the traditional cubic SAPO-34 catalyst. This work provides a new technical route for green and efficient synthesis of SAPO-34 catalysts with improved MTO performance.

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Section: Catalytic Performancesupporting

confidence: 91%

Green and efficient dry gel conversion synthesis of SAPO-34 catalyst with plate-like morphology

Wang

et al. 2016

Pet. Sci.

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“…Figure shows the XRD patterns acquired for the as‐synthesized mono and multi heteroatoms substituted into SAPO‐34 framework. These patterns, irrespective of the modifier ion, reveal the formation of a typical zeolite CHA crystalline structure (JCPDS: 01‐087‐1527) by diffraction peaks at 2θ = 9.5°, 12.9°, 16.0°, 17.7°, 20.6°, 24.9°, 25.9°, 30.6°, and 31.0°, which are identical to those of SAPO‐34 reported in the literature . All the samples were subjected to the same synthesis procedure, irrespective of the type of metal ions.…”

Section: Resultssupporting

confidence: 72%

Incorporation of mono and bimetallic MnNi into SAPO‐34 framework used in conversion of methanol to ethylene and propylene: Alteration of acidic properties and catalytic performance

Sadeghpour

Haghighi

2018

Asia-Pacific J Chem Eng

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Nanostructured Ni, and MnNi) catalysts were synthesized by hydrothermal method using diethylamine (DEA) as template. The influence of Ni, Mn, and MnNi metal ions incorporation into the SAPO-34 framework was investigated on its physicochemical properties and catalytic performance towards methanol to light olefins. The samples were characterized by X-ray diffraction, field emission scanning electron microscopy, particle size distribution, energy dispersive X-ray, Brunner-Emmett-Teller, Fourier transform infrared, UV-vis spectroscopy, and temperature-programmed desorption of ammonia techniques. The results of X-ray diffraction patterns revealed that various metals, based on their unique characteristics, play different roles in the crystallization of SAPO-34 crystalline phase. The energy dispersive X-ray micrographs indicated appropriate distribution of Mn metal ions in comparison with Ni modifier. The catalytic performance of these catalysts showed that the type of metal ions has low effect on methanol conversion, whereas it has considerable effect on stability and products selectivity. The stability of MnAPSO-34 catalyst is much higher than the others. The selectivity of olefins for this sample with a high specific surface area and proper distribution of strong/weak acid sites was about 98% after 10 hr. The main steps of metal ions incorporation into the SAPO-34 framework and a possible reaction mechanism for methanol to light olefins process were discussed in details.

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“…The “hydrocarbon pool” mechanism has been widely accepted for the MTO reaction. − “Hydrocarbon pool” species have been identified as carbenium ions − (e.g., heptaMB + and pentaMCP + ions) and polymethylbenzenes (PMBs). ,− During the MTO reaction, methanol or dimethyl ether (DME) is added to PMBs, followed by splitting to generate light olefins as shown in Scheme . Improving the selectivity to light olefins and stability of SAPO-34 catalysts in the MTO process is of great importance for their industrial applications. − Extensive efforts have been devoted to address these issues, such as optimizing the operating conditions, modifying the zeolite pore structure, adjusting the acidity, , controlling the catalyst morphology and size. − …”

Section: Introductionmentioning

confidence: 99%

Tuning Hydrocarbon Pool Intermediates by the Acidity of SAPO-34 Catalysts for Improving Methanol-to-Olefins Reaction

Peng

Wang

et al. 2018

ACS Sustainable Chem. Eng.

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Methanol-to-olefins (MTO) has received great attention, in which abundant renewable resources of biomass and biogas can be utilized as promising alternatives to crude oil in the production of light olefins. SAPO-34 is one of the most promising catalysts in MTO reaction, providing excellent selectivity toward ethylene and propylene. In this work, highly crystalline SAPO-34 catalysts with different SiO2/Al2O3 ratios have been applied in MTO reaction to elucidate the effects of particle size and acidity on the “hydrocarbon pool” intermediate distribution, which remarkably influence their catalytic performance in the reaction. A smaller particle size of SAPO-34 catalyst (e.g., 120–360 mesh) can improve the catalyst lifetime, but nearly no effect on the product distribution. A suitable density of Brønsted acid sites (BAS) was found to effectively prolong the catalyst lifetime and enhance the total selectivity toward light olefins (ethylene and propylene). GC–MS and NMR analysis demonstrates that the suitable BAS density on SAPO-34 can suppress hydrogen transfer reaction for the formation of paraffins and the formation of polycyclic aromatics. The suitable BAS density was found to promote the formation of active “hydrocarbon pool” species, such as polymethylbenzenes, at a very low aromatic/CH3 ratio compared to those having a much higher BAS density (>0.2), which can significantly boost the selectivities to olefins as desired products and improve the catalyst lifetime at 100% conversion of methanol. Therefore, this work provides a potential way for the development of suitable catalysts for MTO reaction with high olefin selectivity and improved lifetime.

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Effect of SAPO-34 molecular sieve morphology on methanol to olefins performance

Cited by 27 publications

References 11 publications

Green and efficient dry gel conversion synthesis of SAPO-34 catalyst with plate-like morphology

Green and efficient dry gel conversion synthesis of SAPO-34 catalyst with plate-like morphology

Incorporation of mono and bimetallic MnNi into SAPO‐34 framework used in conversion of methanol to ethylene and propylene: Alteration of acidic properties and catalytic performance

Tuning Hydrocarbon Pool Intermediates by the Acidity of SAPO-34 Catalysts for Improving Methanol-to-Olefins Reaction

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