نتایج جستجو برای: zsm
تعداد نتایج: 1752 فیلتر نتایج به سال:
ZSM-5-containing catalytic additives are widely used in oil refineries to boost light olefin production and improve gasoline octanes in the Fluid Catalytic Cracking (FCC) process. Under the hydrothermal conditions present in the FCC regenerator (typically >700 °C and >8% steam), FCC catalysts and additives are subject to deactivation. Zeolites (e.g., Rare Earth USY in the base catalyst and ZSM-...
Molecular-sized micropores of ZSM-5 zeolite catalysts provide spatial restrictions around catalytic sites that allow for shape-selective catalysis. However, the fact that ZSM-5 has two main pore systems with different geometries is relatively unexploited as a potential source of additional shape selectivity. Here, we use confocal laser-scanning microscopy to show that by changing the polarity o...
The absorption of carbon monoxide with H-ZSM-5 and metal-substituted Li-ZSM-5 zeolites has been investigated by Ž . using both cluster and embedded cluster approaches at the HFr6–31G d,p level of theory. For the H-ZSM-5 zeolite, the binding energy of CO on a 3T quantum cluster is predicted to be 2.25 kcalrmol for the C-bound complex. The O-bound complex was found to be less stable by about 0.84...
_____________________________________________________________ Different catalysts based on Y-zeolite, ZSM-5 and amorphous kaolin were prepared and characterized. The catalytic cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB), 1,4diisopropylbenzene (1,4-DIPB) and n-dodecane were used to investigate the effect of catalyst nature on the catalytic performance. Cracking the largest molecule (1,3,5...
In order to improve the sensing properties of tin dioxide gas sensor, four kinds of different SiO₂/Al₂O₃ ratio, different particle size of MFI type zeolites (ZSM-5) were coated on the SnO₂ to prepared zeolite modified gas sensors, and the gas sensing properties were tested. The measurement results showed that the response values of ZSM-5 zeolite (SiO₂/Al₂O₃ = 70, grain size 300 nm) coated SnO₂ ...
Syntheses of ZSM-5 coatings on stainless steel plates were carried out via the substrate heating method. The reaction mixture was kept at temperatures below 100 C, while the metal plates were heated to temperatures above 100 C. It was demonstrated that continuous ZSM-5 coatings of different textures with different crystal morphologies and void fractions could be formed. ZSM-5 coatings were char...
A series of supported phosphotungstic acid (H3PW12O40, HPW) catalysts, including HPW/β, HPW/Sn-β, HPW/H-Y, HPW/H-ZSM-5, HPW/USY, HPW/ReUSY, and HPW/SBA-15, were prepared using an impregnation method for alcoholysis of fructose to ethyl levulinate in ethanol. Among these catalysts, HPW/H-ZSM-5 showed the highest catalytic activity, and the yield of ethyl levulinate from fructose increased with i...
LaTonia Belcher and Sarah Teren under the supervision of: John Regalbuto and Marc Schreier Department of Chemical Engineering University of Illinois at Chicago ______________________________________________________________________ ABSTRACT: Currently the procedure on how to make over exchanged Cu-ZSM-5 is well known and can be made at many different exchange rates [1]. However, no one understan...
As stock of crude oil is limited, new resources for fuel and petrochemicals are required to be developed. Natural gas or biogas can be easily converted into methanol which can be converted into gasoline and olefins. This study uses zeolite catalyst (ZSM-5) and its modification by Ni to convert methanol to hydrocarbons (MTH). Catalysts are studied at different temperatures and at different loadi...
Adsorption of carbonmonoxide on the silver ion-exchanged Ag-ZSM-5 zeolite has been studied using both quantum cluster and embedded cluster at the models B3LYP/6-31G(d,p) level of theory. The Ag...Oz distance in Ag-ZSM-5 complexes is predicted to be 2.26 Å for the quantum cluster and 2.32 Å for the embedded cluster, the latter is in agreement with the experimental value of 2.30 + 0.03 Å. The opt...
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