Coking is a major deactivation mechanism of catalysts for vapor phase upgrading of pyrolysis oils.  While catalysts can be regenerated to remove coke build up, the minimization of coking improves catalyst activity lifetime and reduces detrimental impacts on selectivity, which are important objectives in order to achieving maximum yield of desired upgraded oil products.  Porous catalyst particles with large surface areas accumulate coke throughout their interior, and thereby exhibit spatial and temporal intra-particle gradients of catalyst activity that evolve with time on stream.  We present studies of the coking and deactivation of H-ZSM-5 catalyst particles with a combination of characterization and modeling techniques.  Catalyst particles were characterized with X-Ray Computed Tomography (XCT) to determine the distribution of porosity throughout the particle, and coked particles were characterized with microscopic and elemental analysis techniques.  The catalyst particle characterization data formed the basis for a multi-physics particle model with realistic structure and intra-particle transport which also includes a lumped reaction scheme to provide kinetics for the catalysis reactions.  The particle model captures the effects of coke accumulation and catalyst deactivation on conversion yields and product distributions under simulated process stream conditions.  Results from both the characterization and simulation aspects of the research will be shown along with comparisons to experimental conversion results.

Measurement and simulation of coking of catalyst particles in vapor phase upgrading

255th National Meeting (2018)

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