Upgrading hydrocarbons, zeolite

Industrial applications of zeolites cover a broad range of technological processes from oil upgrading, via petrochemical transformations up to synthesis of fine chemicals [1,2]. These processes clearly benefit from zeolite well-defined microporous structures providing a possibility of reaction control via shape selectivity [3,4] and acidity [5]. Catalytic reactions, namely transformations of aromatic hydrocarbons via alkylation, isomerization, disproportionation and transalkylation [2], are not only of industrial importance but can also be used to assess the structural features of zeolites [6] especially when combined with the investigation of their acidic properties [7]. A high diversity of zeolitic structures provides us with the opportunity to correlate the acidity, activity and selectivity of different structural types of zeolites. 

ZEOLITE CATALYSTS IN THE UPGRADING OF LOW-OCTANE HYDROCARBON FEEDSTOCKS TO UNLEADED GASOLINES... 

During pyrolysis of biomass, often in a fluidized-bed reactor, the substrate thermally decomposes into vapors that can subsequently be driven over a zeolite catalyst bed, where the vapors are converted to hydrocarbons like aromatics, olefins, and a variety of partially deoxygenated compounds, next to CO, CO, water, and cokes. Afterward, the aromatics, olefins, deoxygenated products, and water are condensed into an upgraded bio-oil. 

Studied [269,272,273], Both ZSM-5 catalysts emerge as the best catalysts with the highest yields of hydrocarbon products and lowest coke formation [269], The aromatics yield tends to decrease in the order ZSM-5 >H-beta>H-mordenite>H-ferrierite/HY [273], Stefanidis et al. demonstrated that, in comparison to a range of amorphous catalysts such as alumina, zirconia/ titania, and magnesium oxide, ZSM-5 is more suitable for the reduction of undesirable compounds and production of aromatics in the upgrading of pyrolysis vapors from beech wood [274], The excellent performance of ZSM-5 is attributed to the important role of its medium pore size [269], Besides, Park et al. pointed out that ZSM-5 is more efficient than Y zeolites due to the proper distribution of strong acid sites [275],... 

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