Effect of Size Factor on the Activity of Zeolites in the Liquid-Phase Cracking of Hydrocarbons

Дементьев, К. И.; Palankoev, T. A.; Kuznetsov, P. S.; Abramova, D. S.; Romazanova, D. A.; Makhin, D. Yu.; Максимов, А. Л.

doi:10.1134/s0965544120010065

Cited by 5 publications

(2 citation statements)

References 23 publications

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“…The β has a broad product distribution, and the selectivity toward benzene, toluene, ethylbenzene, and xylenes are almost the same because of medium pore size. The data obtained are in accordance with the data published for the shape selectivity and molecular sieve effect of the zeolites and with the works where this phenomenon is studied for some other reactions [ 44 , 45 , 46 , 47 ].…”

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confidence: 91%

Catalytic Pyrolysis of Polystyrene Waste in Hydrocarbon Medium

et al. 2023

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The fast catalytic pyrolysis of polystyrene in the hydrocarbon medium (light and heavy cycle oil) over zeolite catalysts at 450–550 °C was investigated. The influence of reaction conditions (medium, temperature, vapor residence time, polystyrene concentration) on polymer conversion and product distribution was studied. It was found that the polymer conversion is close to 100%, while ethylbenzene, benzene, and toluene are the main products of its transformation. The maximum yield of ethylbenzene (80%) was achieved at 550 °C, vapor residence time 1–2 s, polystyrene concentration 10%, and heavy cycle oil as the medium. The influence of zeolite topology on product distribution was explored. The possible mechanism of polystyrene pyrolysis was proposed.

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Section: Resultssupporting

confidence: 91%

Catalytic Pyrolysis of Polystyrene Waste in Hydrocarbon Medium

et al. 2023

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“…Li et al explored the effects of gold nanoparticles, but the improvement of the cracking rate of JP-10 only achieved 10% with the dispersion stability of metal nanoparticles, limiting the use as a catalyst in JP-10 decomposition. On the other hand, zeolitesmicroporous, aluminosilicate mineralshave emerged as potentially effective catalysts in the decomposition and also oxidation of JP-10 due to their high catalytic activity, thermal stability, cation exchange capability, shape selectivity, and effective acidic sites in their structural framework. ,− The catalytic activity of zeolites critically depends on multiple factors such as the aluminum content in terms of the silicon dioxide (SiO 2 ) to aluminum oxide (Al 2 O 3 ) ratio of the zeolite framework, ,− the type of cation (H + , Na + , K + , and Li + ) exchange in the aluminum framework, , the pore size, ,, the particle size of the zeolite, and also the moisture level . Particular attention has been devoted to Zeolite Socony Mobil 5 (ZSM-5)a Mobil five (MFI) type of zeolite, where its framework is formed by bonding multiple pentasil units. , This structure creates 10-membered ring micropores of 0.51 to 0.56 nm in diameter .…”

Section: Introductionmentioning

confidence: 99%

Catalytic Effects of Zeolite Socony Mobil-5 (ZSM-5) on the Oxidation of Acoustically Levitated exo-Tetrahydrodicyclopentadiene (JP-10) Droplets

et al. 2021

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Jet propulsion 10 (JP-10) droplets with and without aluminum nanoparticles in conjunction with HZSM-5 zeolite and surfactants were ultrasonically levitated, and their oxidation processes were explored to identify how the oxidation process of JP-10 is catalytically affected by the HZSM-5 zeolites and how the surfactant and Al NPs in the system impacted the key experimental parameters of the ignition such as ignition delay time, burn rate, and the maximum temperatures. Singly levitated droplets were ignited using a carbon dioxide laser under an oxygen−argon atmosphere. Pure JP-10 droplets and JP-10 droplets with silicon dioxide of an identical size distribution as the zeolite HZSM-5 did not ignite in strong contrast to HZSM-5-doped droplets. Acidic sites were found to be critical in the ignition of the JP-10. With the addition of the surfactant, the characteristic features of the JP-10 ignition were improved, so the ignition delay time of the zeolite-JP-10 samples were decreased by 2−3 ms and the burn rates were increased by 1.3 to 1.6 × 10 5 K s −1 . The addition of Al NPs increased the maximum temperatures during the combustion of the systems by 300−400 K. Intermediates and end products of the JP-10 oxidation over HZSM-5 were characterized by UV−vis emission and Fourier-transform infrared transmission spectroscopies, revealing key reactive intermediates (OH, CH, C 2 , O 2 , and HCO) along with the H 2 O molecules in highly excited rovibrational states. Overall, this work revealed that acetic sites in HZSM-5 are critical in the catalytic ignition of JP-10 droplets with the addition of the surfactant and Al NPs, enhancing the oxidation process of JP-10 over HZSM-5 zeolites.

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Kinetics of Liquid-Phase Condensation of Propylene with Formaldehyde over H–MFI and H–BEA Zeolites

2022

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This study investigated the kinetic patterns of the liquid-phase Prins condensation of propylene with formaldehyde in the range of 120–180°C over H–MFI and H–BEA zeolites. The apparent reaction order with respect to formaldehyde was found to vary between 0.1 and 0.2 for H–BEA and to be close to zero for H–MFI. The apparent activation energy for H–MFI and H–BEA was 26.1±0.6 kJ/mol and 20.0±4.0 kJ/mol, respectively. Based on these results, the reaction was demonstrated to occur in the intradiffusion or transition region; the calculated Thiele modulus and effectiveness factor further confirmed this fact. The diffusion limitations were partially removed by raising the initial formaldehyde concentration, as indicated by an increase in the apparent order of formaldehyde conversion to 1.0 for H–BEA and to 0.4 in the H–MFI case. To describe the substrate transformations observed, a modernized reaction mechanism was proposed.

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Effect of Size Factor on the Activity of Zeolites in the Liquid-Phase Cracking of Hydrocarbons

Cited by 5 publications

References 23 publications

Catalytic Pyrolysis of Polystyrene Waste in Hydrocarbon Medium

Catalytic Pyrolysis of Polystyrene Waste in Hydrocarbon Medium

Catalytic Effects of Zeolite Socony Mobil-5 (ZSM-5) on the Oxidation of Acoustically Levitated exo-Tetrahydrodicyclopentadiene (JP-10) Droplets

Kinetics of Liquid-Phase Condensation of Propylene with Formaldehyde over H–MFI and H–BEA Zeolites

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