Elucidating coke formation and evolution in the catalytic steam reforming of biomass pyrolysis volatiles at different fixed bed locations
[EN] The evolution and the main mechanisms of catalyst deactivation have been assessed throughout continuous operation in the steam reforming of biomass pyrolysis volatiles. Biomass pyrolysis was conducted in a conical spouted bed reactor at 500 °C and the subsequent reforming step in a fixed bed re...
| Autores: | , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universidad del País Vasco |
| Repositorio: | Addi. Archivo Digital para la Docencia y la Investigación |
| OAI Identifier: | oai:addi.ehu.eus:10810/71836 |
| Acceso en línea: | http://hdl.handle.net/10810/71836 |
| Access Level: | acceso abierto |
| Palabra clave: | biomass pyrolysis steam reforming deactivation coke deposition hydrogen bio‐oil |
| Sumario: | [EN] The evolution and the main mechanisms of catalyst deactivation have been assessed throughout continuous operation in the steam reforming of biomass pyrolysis volatiles. Biomass pyrolysis was conducted in a conical spouted bed reactor at 500 °C and the subsequent reforming step in a fixed bed reactor at 600 °C. The influence of catalyst location on the reforming reactor is also analyzed at different axial positions. Deactivated samples have been characterized by N2 adsorption‐desorption, XRD, SEM and TEM images, TPO, Raman and FTIR spectroscopies. Coke deposition is the main cause of initial catalyst decay, with no sintering or oxidation of Ni sites being observed. As reaction proceeds, a deactivation front is observed along the reforming catalytic bed, with coke location within the catalyst, and its nature and composition depending on the volatile composition reaching each axial position in the bed. At the inlet section of the catalytic bed (A1), the coke is deposited on Ni sites and is of rather oxygenated nature. At further axial bed locations, the catalyst is in contact with a volatile stream whose composition has been considerably modified, which leads to the formation of a more structured coke with higher graphitization degree and made up of more condensed polyaromatic compounds. Moreover, the coke deposited on all deactivated samples does not present any specific morphology, which is evidence of its amorphous structure regardless the bed location and reaction time. |
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