Current biomass deoxygenation technologies require large quantities H2. Gaseous hydrogen is not a naturally‐occurring raw material and is largely produced industrially via natural gas/methane steam reforming. Due to its high thermodynamic stability, direct use of methane as a hydrogen‐donor for deoxygenation of complex oxygenates has not yet been demonstrated. Using catalytic pyrolysis studies performed at 700 °C with isotope labeled methane and glucose over Ni, Pt, Mo, and Ga impregnated HZSM‐5 (Si/Al ratio 30), here we show that methane, in fact, could be used as a direct hydrogen donor for deoxygenation reactions. The amount of aromatic hydrocarbons produced increased primarily in the presence of Mo (125 % increase), and to a lesser degree, Pt (50 % increase), and Ni (22 % increase) impregnated HZSM‐5 catalysts in a methane environment. Based on the metal present, results indicate the occurrence of distinct and concurrent reactions to various degrees: methane (steam) reforming and oxygenate dehydration reaction; independent aromatization of methane and oxygenates; and an intriguing methane oxygenate cross‐coupling reaction where both hydrogen and carbon from methane ending up in resultant deoxygenated aromatic products. This technique paves way for the direct use of methane/natural gas for deoxygenation reactions critical to biorefining.
The effective deoxygenation of oxygenates remains a major challenge that needs to be overcome for industrial‐scale conversion of biomass to fuels. Present technology uses expensive gaseous hydrogen for deoxygenation. This work looks at the possibility of using methane or natural gas as an alternative for the deoxygenation process. Catalytic pyrolysis studies were carried out using furan as the model oxygenate in the presence of methane in a fixed‐bed reactor over 5 % Ni/HZSM‐5 as catalyst. The effects of temperature and space velocity on the catalyst activity, reaction kinetics, and deactivation behavior were studied. It was found that the deoxygenation of furan was first and second order with respect to furan and methane concentration, respectively. Deactivation studies suggested that catalyst deactivation takes place through poisoning, fouling, and sintering.
more » « less- PAR ID:
- 10034913
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemical Engineering & Technology
- Volume:
- 40
- Issue:
- 6
- ISSN:
- 0930-7516
- Page Range / eLocation ID:
- p. 1176-1183
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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