Catalytic conversion of light hydrocarbons to propylene over MFI-zeolite/metal-oxide composites

Hodoshima, Shinya; Motomiya, Azusa; Wakamatsu, Shuhei; Kanai, Ryuichi; Yagi, Fuyuki

doi:10.1016/j.micromeso.2015.12.044

Cited by 13 publications

(13 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is possible that the difference in acidity is responsible for the difference in selectivity. As the Cr ZSM-5 has slightly higher total acidities when compared to Fe, readsorption of light olefins on acid sites may occur leading to secondary aromatisation reactions thus also indicating zeolites with a lower acid site density would give selectivity to light olefins while suppressing aromatics formation [18]. The selectivity to liquid products for the metal modified catalysts is shown in Fig.…”

Section: Catalytic Performancementioning

confidence: 98%

Catalytic cracking of naphtha: The effect of Fe and Cr impregnated ZSM-5 on olefin selectivity

2018

View full text Add to dashboard Cite

This study focuses on the modification of ZSM-5 in order to enhance the catalytic cracking of refinery naphtha to produce light olefins. ZSM-5 was metal modified using different loadings (0.5-5 wt%) of Fe and Cr via the impregnation method. The metal modified ZSM-5 samples are compared and the effect of metal loading on the physicochemical properties and catalytic performance is investigated. Fe and Cr modification had an effect on both the physicochemical properties of the catalysts as well as catalytic activity and selectivity. Metal loading caused a decrease in the specific surface area which decreased further with increased metal loading. Fe had a greater effect on the total acidity in particular strong acid sites when compared to Cr. The optimum Fe loading was established which promoted selectivity to olefins, in particular propylene. Fe also had a dominant effect on the P/E ratio of which a remarkable ratio of five was achieved as well as enhanced the stability of the catalyst. Cr was found to be a good promoter for selectivity to BTX products with a two-fold increase observed when compared to Fe-modified catalysts.

show abstract

Section: Catalytic Performancementioning

confidence: 98%

Catalytic cracking of naphtha: The effect of Fe and Cr impregnated ZSM-5 on olefin selectivity

2018

View full text Add to dashboard Cite

show abstract

“…The MFI-type zeolites containing iron, gallium and aluminum species (Fe _ Ga _ Al-MFI) and the MFI-type zeolite containing iron and aluminum species (Fe _ Al-MFI) were synthesized by the conventional hydrothermal method 8), 9) . Aqueous solution containing silicon, iron, gallium and aluminum sources and tetrapropylammonium bromide as an organic structure-directing agent were prepared as the mother gel with the following molar compositions: (1) Si/ T 25, 50, 75, 90, 150, 200 and 500, Fe/T 0.4, Ga/T 0.2, Al/T 0.4, T Fe Ga Al; (2) Si/T 25, Fe/T 0.4, Al/T 0.6, T Fe Al.…”

Section: Synthesis and Characterization Of Mfi-type Zeolitesmentioning

confidence: 99%

“…Zeolite-based Composites Fe _ Ga _ Al-MFI/Al2O3 composite catalysts, consisting of Fe _ Ga _ Al-MFI zeolites and aluminum _ oxide binder, were prepared according to the following steps 8), 9) . Sodium-type Fe _ Ga _ Al-MFI zeolites with the following molar ratios in mother gel: Si/T 25, 50, 75, 90, 150, 200 and 500, Fe/T 0.4, Ga/T 0.2, Al/T 0.…”

Section: Preparation and Characterization Of Mfimentioning

confidence: 99%

“…The weight ratios of zeolite to binder in the composite catalysts were measured by the XRF technique (XRF; PW2400/00, Philips). The morphology and the elemental analysis of silicon and aluminum atoms of the Fe _ Ga _ Al-MFI/Al2O3 composite catalyst (molar ratio in mother gel: Si/T 25, Fe/T 0.4, Ga/T 0.2, Al/T 0.4, T Fe Ga Al, weight ratio of Fe _ Ga _ Al-MFI/Al2O3: 75/25), was examined by the scanning electron microscopy equipped with an energy-dispersive fluorescence X-ray spectrometer (SEM-EDX; Hitachi, Ltd.) 9) . The morphology of the Fe _ Ga _ Al-MFI/SiO2 and the Fe _ Ga _ Al-MFI/Al2O3 composite catalysts (molar ratio in mother gel: Si/T 200, Fe/T 0.4, Ga/T 0.2, Al/T 0.4, T Fe Ga Al, weight ratio of Fe _ Ga _ Al-MFI/Al2O3 or Fe _ Ga _ Al-MFI/SiO2: 85/15) were examined by the field emission scanning electron microscopy (FE-SEM; Ultra55, ZEISS) using an energy-dispersive fluorescence X-ray spectrometer (EDX; NSS-312E, Thermo Fischer Scientific K.K.)…”

Section: T Fe Gamentioning

confidence: 99%

See 1 more Smart Citation

Catalytic Cracking of Light-naphtha Fraction over Zeolite-based Composites for On-purpose Propylene Production

Hodoshima¹

2021

J. Jpn. Petrol. Inst.

Self Cite

View full text Add to dashboard Cite

Catalytic cracking of light-naphtha fraction over zeolite-based composites in fixed-bed mode was investigated to establish an efficient method for on-purpose propylene production. The composite catalysts, consisting of MFI-type zeolites containing iron, gallium and aluminum species (Fe _ Ga _ Al-MFI) and metal-oxide binder (e.g., silicon oxide, aluminum oxide), were employed for cracking of light-naphtha fraction. Fe _ Ga _ Al-MFI zeolites as matrix, containing each heteroatom at adequate ratio in the zeolite framework, exhibited both overall acid strength suitable for selective formation of light olefins and enhanced activity for dehydrogenation of light alkanes to alkenes, so that high overall yields of light olefins (ethylene, propylene and butenes) were attained by suppressing aromatics formation compared to cracking of light-naphtha fraction using conventional Al-MFI zeolite (ZSM-5). The unique acidity of the Fe _ Ga _ Al-MFI zeolite was maintained in the extruded form by using neutral and inactive silicon _ oxide binder, which was selected to enhance mechanical strength and/or reduce pressure drop during reaction. The zeolite-based composite (Fe _ Ga _ Al-MFI/SiO2) selectively converted light-naphtha fraction (n-hexane) into light olefins including propylene with catalyst lifetime longer than 2000 h, suitable for fixed-bed operation, due to its excellent resistance to coke formation. Furthermore, the cracking reactions proceeded in the absence of steam at moderate temperatures below 650 °C, so catalytic cracking using the present zeolite-based composite saved considerable thermal energy required in the reaction unit, and the total amount of hydrocarbon feedstock was reduced by ca. 15 %, compared to conventional thermal cracking at 850 °C. The present review discusses the excellent properties of these zeolite-based catalysts and catalytic cracking of light-naphtha fraction emphasizing the catalytic chemistry and reaction engineering of the catalytic process.

show abstract

“…Due to the decrease of the acidity strength, the cracking products are easier to desorb, which may restrain the second reaction between light alkenes generate from the primary cracking reaction, resulting in higher light alkene selectivity ( Figure 18) and less carbon deposition [44]. Hodoshima et al [113] prepared ZSM-5 zeolite containing Fe, Ga and Al simultaneously. The acid strength of Fe-Ga-Al ZSM-5 zeolite is weaker than that of the conventional ZSM-5 zeolite, which enhanced the selectivity of propylene and suppressed the generation of carbon deposition.…”

Section: Acidity Strengthmentioning

confidence: 99%

Strategies to Enhance the Catalytic Performance of ZSM-5 Zeolite in Hydrocarbon Cracking: A Review

2017

View full text Add to dashboard Cite

ZSM-5 zeolite is widely used in catalytic cracking of hydrocarbon, but the conventional ZSM-5 zeolite deactivates quickly due to its simple microporous and long diffusion pathway. Many studies have been done to overcome these disadvantages recently. In this review, four main approaches for enhancing the catalytic performance, namely synthesis of ZSM-5 zeolite with special morphology, hierarchical ZSM-5 zeolite, nano-sized ZSM-5 zeolite and optimization of acid properties, are discussed. ZSM-5 with special morphology such as hollow, composite and nanosheet structure can effectively increase the diffusion efficiency and accessibility of acid sites, giving high catalytic activity. The accessibility of acid sites and diffusion efficiency can also be enhanced by introducing additional mesopores or macropores. By decreasing the crystal size to nanoscale, the diffusion length can be shortened. The catalytic activity increases and the amount of carbon deposition decreases with the decrease of crystal size. By regulating the acid properties of ZSM-5 with element or compound modification, the overreaction of reactants and formation of carbon deposition could be suppressed, thus enhancing the catalytic activity and light alkene selectivity. Besides, some future needs and perspectives of ZSM-5 with excellent cracking activity are addressed for researchers' consideration.

show abstract

Catalytic conversion of light hydrocarbons to propylene over MFI-zeolite/metal-oxide composites

Cited by 13 publications

References 17 publications

Catalytic cracking of naphtha: The effect of Fe and Cr impregnated ZSM-5 on olefin selectivity

Catalytic cracking of naphtha: The effect of Fe and Cr impregnated ZSM-5 on olefin selectivity

Catalytic Cracking of Light-naphtha Fraction over Zeolite-based Composites for On-purpose Propylene Production

Strategies to Enhance the Catalytic Performance of ZSM-5 Zeolite in Hydrocarbon Cracking: A Review

Contact Info

Product

Resources

About