Zeolite catalysis and processes for bioethanol conversion to biohydrocarbons

The potential of zeolite catalysts, particularly those based on H-ZSM-5 zeolite, in the conversion of ethanol to hydrocarbon compounds is reviewed. The conversion of ethanol to ethylene over H-ZSM-5-based catalysts has already been realized at the industrial level. The catalyst development and the process features in this field are critically discussed. The characteristics of phosphoric-acid-treated H-ZSM-5, like that used industrially in the AtolTM process, are also described. In the context of technologies not yet developed at the industrial level, the production of other light olefins, such as propene and butenes, on zeolite catalysts is also critically considered for completeness. The state of development of the ethanol-to-gasoline and the ethanol-to-aromatics processes is described, with a focus on catalytic materials and suitable operational conditions. This critical review highlights the potential of zeolites in bioethanol conversion, with special emphasis on the future production of renewable hydrocarbon intermediates and biofuels.