How the pretreatment temperature of zeolitic catalysts can affect the reaction temperature of methanol to olefins and gasoline processes

The dehydration of methanol to produce light olefins and gasoline, known as MTO (methanol-to-olefins) process requires acidic catalysts that maintain their acidity at reaction temperatures. Zeolites, such as SAPOs and ZSM-5, are commonly used for this purpose due to their acidic centers. The initial...

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Detalhes bibliográficos
Autores: Yunes, Simón, Rosas, Abel Gaspar, Gil Bravo, Antonio
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Recursos:Universidad Pública de Navarra
Repositorio:Academica-e. Repositorio Institucional de la Universidad Pública de Navarra
OAI Identifier:oai:academica-e.unavarra.es:2454/53826
Acesso em linha:https://hdl.handle.net/2454/53826
Access Level:acceso abierto
Palavra-chave:Methanol
Olefins
Dehydration
Temperature-programmed desorption (TPD)
Acidity
Descrição
Resumo:The dehydration of methanol to produce light olefins and gasoline, known as MTO (methanol-to-olefins) process requires acidic catalysts that maintain their acidity at reaction temperatures. Zeolites, such as SAPOs and ZSM-5, are commonly used for this purpose due to their acidic centers. The initial step in these experiments involves the activation or pretreatment of these solids to remove physically adsorbed water from their pores. Inadequate pretreatment can lead to the destruction of the existing Brönsted sites through the dihydroxylation of surface -OH groups. Therefore, it is crucial to pretreat the zeolites properly to preserve the Brönsted sites. One method is to subject the fresh catalyst to programmed dehydration, which involves desorption at a controlled temperature while monitoring the appearance of water that results from Brönsted site dihydroxylation. The temperature at which the dehydration peak appears determines the optimal reaction temperature. The results presented in this work will demonstrate the progressive deactivation of the catalysts when the reaction temperature exceeds 400 °C.