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Title: Characterization of Deactivated Bio-oil Hydrotreating Catalysts

Deactivation of bio-oil hydrotreating catalysts remains a significant challenge because of the poor quality of pyrolysis bio-oil input for hydrotreating and understanding their deactivation mode is critical to developing improved catalysts and processes. In this research, we developed an understanding of the deactivation of two-step bio-oil hydrotreating catalysts (sulfided Ru/C and sulfided CoMo/C) through detailed characterization of the catalysts using various complimentary analytical techniques. Severe fouling of both catalysts by carbonaceous species was the major form of deactivation, which is consistent with the significant loss of surface area and pore volume of both deactivated catalysts and the significant increase of the bulk density. Further analysis of the carbonaceous species by thermogravimetric analysis and x-ray photoelectron spectroscopy indicated that the carbonaceous species was formed by condensation reaction of active species such as sugars and sugar derivatives (aldehydes and ketones) in bio-oil feedstock during bio-oil hydrotreating under the conditions and catalysts used. Microscopy results did not show metal sintering of the Ru/C catalyst. However, X-ray diffraction indicated a probable transformation of the highly-active CoMoS phase in the sulfided CoMo/C catalyst to Co8S9 and MoS2 phase with low activity. Loss of the active site by transport of inorganic elements from the bio-oil andmore » the reactor construction material onto the catalyst surface also might be a cause of deactivation as indicated by elemental analysis of spent catalysts.« less
Authors:
;
Publication Date:
OSTI Identifier:
1252847
Report Number(s):
PNNL-SA-110629
Journal ID: ISSN 1022-5528; 48018; BM0101010
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Topics in Catalysis; Journal Volume: 59; Journal Issue: 1
Publisher:
Springer
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
bio-oil hydrotreating; catlayst; deavtivation; characterization; Environmental Molecular Sciences Laboratory