Synthesis of hierarchal SAPO-34 nano catalyst with dry gel conversion method in the presence of carbon nanotubes as a hard template

Rimaz, Sajjad; Halladj, Rouein; Askari, Sima

doi:10.1016/j.jcis.2015.11.005

Cited by 42 publications

(18 citation statements)

References 37 publications

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“…Same results are observed by Rimaz et al [82]. In this experiment DEA and carbon nano tubes (CNT) were used as organic and hard template respectively, which makes this dry gel method a different from ordinary methods such as VPT or SAC.…”

Section: Crystallization Timesupporting

confidence: 64%

“…Rimaz et al investigation also shows the same results [82]. Two samples with same synthesis condition dried at 130°C and 200°C respectively.…”

Section: Gel Drying Temperaturesupporting

confidence: 58%

“…Rimaz et al also investigates the effect water/dry gel mass ratio [82]. As it can be seen in Table 10, sample S1 with lower water/dry gel ratio shows lower relative crystallinity, as it was expected, and smaller particle size range due to the lack of liquid phase which limits mass transport.…”

Section: Water/dry Gel Mass Ratiomentioning

confidence: 94%

“…Also, crystallinity of particles is improved by increasing water/dry gel ratio. The reason is that a great number of water molecules are placed in the crystal framework, controlling the distance between nutrients for effective interaction, making their structure more regular and also improving the free diffusion of substrates [82,83].…”

Section: Water/dry Gel Mass Ratiomentioning

confidence: 99%

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Different techniques and their effective parameters in nano SAPO-34 synthesis: A review

et al. 2016

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Section: Crystallization Timesupporting

confidence: 64%

“…Rimaz et al investigation also shows the same results [82]. Two samples with same synthesis condition dried at 130°C and 200°C respectively.…”

Section: Gel Drying Temperaturesupporting

confidence: 58%

Section: Water/dry Gel Mass Ratiomentioning

confidence: 94%

Section: Water/dry Gel Mass Ratiomentioning

confidence: 99%

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Different techniques and their effective parameters in nano SAPO-34 synthesis: A review

et al. 2016

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“…There are some parameters, such as template [12][13][14][15][16], Si/Al The XRD patterns of the synthesized samples are given in Figure 1. It can be seen that all the samples are in agreement with that of the CHA-structure SAPO-34 (PDF 47-0617) [2].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of SAPO-34 Molecular Sieves via Novel Intermittent Hydrothermal Treatment and Its Effect on the Crystallization and Product Properties

et al. 2017

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Intermittent hydrothermal treatment was introduced into the synthesis of SAPO-34 molecular sieves to control the nucleation and the growth in the crystallization. The effect of the crystallization time, the order of long-time and short-time crystallization in two-stage crystallization, and frequency in multi-stage crystallization on synthesis, physicochemical properties and catalytic performance for conversion of methanol to light olefins (MTO) has been studied. The results show that pure SAPO-34 can be obtained with increasing crystallization time. The interruption of the initial crystallization is more beneficial for improving the Si distribution and the MTO catalytic performance of SAPO-34 molecular sieves. The sample obtained by repeatedly alternating heating and cooling during crystallization shows smaller particle size, higher acidity, longer lifetimes and higher yields of ethylene than that obtained by the conventional continuous crystallization at high temperature.

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Recent Progress in Methanol‐to‐Olefins (MTO) Catalysts

et al. 2019

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Among the 8-MR molecular sieves, silicoaluminophosphate SAPO-34 with 3D channels and moderate acid strength represents the most interesting one, the light olefins selectivity of which could reach up to 90% or even higher. [7] The excellent MTO performance of SAPO-34 was first reported by Dalian Institute of Chemical Physics (DICP) in 1990. [8] The researchers also demonstrated the good regeneration stability and high-temperature steam stability of Inspired by these pioneering discoveries, extensive research efforts have been devoted to SAPO-34 focusing on the elucidation of its crystallization mechanism, synthesis optimization, and the relevant catalytic studies, which greatly promote the technological development of the MTO process. Although SAPO-34 exhibits high catalytic activity and high selectivity toward light olefins, it suffers a rapid deactivation due to the coke deposition. Moreover, the MTO reaction on SAPO-34 catalyst is highly exothermal. These features determine that the industrial MTO process based on SAPO-34 catalyst has to adopt fluidized bed reactor, which allows efficient heat transfer and enables the continuous regeneration of the catalyst. In 2010, the world's first commercial MTO unit was successfully commissioned in Baotou, China by DICP (named DMTO technology). [5,10] The production capacity of ethylene and propylene is 0.6 Mt a −1 . To supply commercial catalysts for the DMTO unit, a 2000 t a −1 catalyst manufacturing plant was started up in Dalian in 2008. Afterward, DICP developed the DMTO-II technology, in which the byproducts of C 4 + are separated and introduced into a fluidized-bed cracking reactor to improve the yields of ethylene and propylene. Both the cracking unit and the MTO unit share one regenerator and use the same catalyst. By the end of 2018, thirteen DMTO units have been put into operation with a total production capacity of 7.16 Mt a −1 . Moreover, DICP launched the new generation of DMTO catalyst and completed the pilot test of the DMTO-III technology in 2018, both of which aim to further improve the olefins yield of DMTO units. The catalyst and technology development of the DMTO process are summarized in Figure 1.Based on SAPO-34 catalyst, UOP and Norsk Hydro also developed an MTO process with a low-pressure fast fluidizedbed reactor. [11] In 2013, a commercialized MTO plant (0.3 Mt a −1 olefins) was commissioned in Nanjing, China, which combines the UOP/Hydro MTO process and the total/UOP olefin cracking process to enhance the yield of ethylene and propylene. In addition, Shanghai Research Institute of Petrochemical Technology Methanol conversion to olefins, as an important reaction in C1 chemistry, provides an alternative platform for producing basic chemicals from nonpetroleum resources such as natural gas and coal. Methanol-to-olefin (MTO) catalysis is one of the critical constraints for the process development, determining the reactor design, and the profitability of the process. After the construction and commissioning of the world's first MTO plant by Dalian I...

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Synthesis of hierarchal SAPO-34 nano catalyst with dry gel conversion method in the presence of carbon nanotubes as a hard template

Cited by 42 publications

References 37 publications

Different techniques and their effective parameters in nano SAPO-34 synthesis: A review

Different techniques and their effective parameters in nano SAPO-34 synthesis: A review

Synthesis of SAPO-34 Molecular Sieves via Novel Intermittent Hydrothermal Treatment and Its Effect on the Crystallization and Product Properties

Recent Progress in Methanol‐to‐Olefins (MTO) Catalysts

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