Abstract
Hydrotreating catalytic fast pyrolysis (CFP) oil is a promising technology for producing diesel fuel from lignocellulosic biomass to reduce greenhouse gas emissions. Compared to fast pyrolysis oil, CFP oils exhibit a low oxygen content and high stability and can be processed in a single hydrotreater. Two strategies were evaluated for biogenic carbon-incorporation into the diesel production: co-hydrotreating of CFP oil with straight run diesel (SRD) and standalone hydrotreating of CFP oil. Co-hydrotreating 80 vol% SRD and 20 vol% CFP oil at typical conditions of SRD hydrotreating employed at petroleum refineries (325 degrees C, 55 bar) over sulfided NiMo and CoMo catalysts led to products with desirable fuel properties, including indicated cetane numbers (ICNs) of 42-45. While oxygen was efficiently removed from products by co-hydrotreating over both catalysts, NiMo resulted in a higher formation of cycloalkanes and a higher ICN. Over 90% of the carbon in CFP oil was incorporated into the hydrotreated product as determined by C-14 analysis. Standalone hydrotreating of CFP oil was performed at 385 degrees C, 125 bar over NiMo in a single hydrotreating reactor with a two-zone configuration consisting of an initial zone from 150 degrees C to the hydrotreating temperature followed by an isothermal zone. Compared to previously reported isothermal hydrotreating, the new hydrotreating configuration resulted in a similar carbon efficiency but a higher fraction (95 vs. 84 wt%) boiling in the fuel range and significantly improved fuel properties (cetane number of 45 vs. 24). Both co-hydrotreating and standalone hydrotreating of CFP oil strategies showed great potential to produce sustainable diesel fuel with properties meeting standard diesel specifications in an existing petroleum refinery and a customized biorefinery, respectively.
Original language | American English |
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Pages (from-to) | 1121-1131 |
Number of pages | 11 |
Journal | Energy Advances |
Volume | 3 |
Issue number | 5 |
DOIs | |
State | Published - 2024 |
NREL Publication Number
- NREL/JA-5100-88478
Keywords
- biogenic carbon
- catalytic fast pyrolysis
- cetane number
- co-hydrotreating
- diesel
- hydrotreating
- NiMo
- straight run diesel