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Title: Production of low-oxygen bio-oil via ex situ catalytic fast pyrolysis and hydrotreating

Abstract

Catalytic fast pyrolysis (CFP) bio-oils with different organic oxygen contents (4-18 wt%) were prepared in a bench-scale dual fluidized bed reactor system by ex situ CFP of southern pine over HZSM-5, and the oils were subsequently hydrotreated over a sulfided CoMo catalyst at 170 bar. The goal was to determine the impact of the CFP oil oxygen content on hydrotreating requirements. The CFP oils with higher oxygen contents included a variety of oxygenates (phenols, methoxyphenols, carbonyls, anhydrosugars) whereas oxygenates in the 4 wt% oxygen oil were almost exclusively phenols. Phenols were the most recalcitrant oxygenates during hydrotreating as well, and the hydrotreated oils consisted mainly of aromatic and partially saturated ring hydrocarbons. The temperature required to produce oil with <1% oxygen was approximately 350 °C for the CFP oil with the lowest oxygen content whereas temperatures around 400 °C were required for the other CFP oils. The carbon efficiency during hydrotreating slightly decreased as the CFP oil oxygen content increased but remained above 90% in all cases, and the carbon efficiency for the integrated process was dominated by the efficiency of the CFP process. In conclusion, a preliminary technoeconomic evaluation suggested that with the current zeolite-based CFP catalysts, it ismore » economically beneficial to preserve carbon during CFP, at the expense of higher oxygen contents in the CFP oil.« less

Authors:
ORCiD logo [1];  [1];  [1];  [1];  [1]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B)
OSTI Identifier:
1371529
Report Number(s):
NREL/JA-5100-68748
Journal ID: ISSN 0016-2361
Grant/Contract Number:
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Fuel
Additional Journal Information:
Journal Volume: 207; Journal Issue: C; Journal ID: ISSN 0016-2361
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; catalytic fast pyrolysis; hydrotreating; HZSM-5; biomass; technoeconomic analysis

Citation Formats

Iisa, Kristiina, French, Richard J., Orton, Kellene A., Dutta, Abhijit, and Schaidle, Joshua A. Production of low-oxygen bio-oil via ex situ catalytic fast pyrolysis and hydrotreating. United States: N. p., 2017. Web. doi:10.1016/j.fuel.2017.06.098.
Iisa, Kristiina, French, Richard J., Orton, Kellene A., Dutta, Abhijit, & Schaidle, Joshua A. Production of low-oxygen bio-oil via ex situ catalytic fast pyrolysis and hydrotreating. United States. doi:10.1016/j.fuel.2017.06.098.
Iisa, Kristiina, French, Richard J., Orton, Kellene A., Dutta, Abhijit, and Schaidle, Joshua A. 2017. "Production of low-oxygen bio-oil via ex situ catalytic fast pyrolysis and hydrotreating". United States. doi:10.1016/j.fuel.2017.06.098.
@article{osti_1371529,
title = {Production of low-oxygen bio-oil via ex situ catalytic fast pyrolysis and hydrotreating},
author = {Iisa, Kristiina and French, Richard J. and Orton, Kellene A. and Dutta, Abhijit and Schaidle, Joshua A.},
abstractNote = {Catalytic fast pyrolysis (CFP) bio-oils with different organic oxygen contents (4-18 wt%) were prepared in a bench-scale dual fluidized bed reactor system by ex situ CFP of southern pine over HZSM-5, and the oils were subsequently hydrotreated over a sulfided CoMo catalyst at 170 bar. The goal was to determine the impact of the CFP oil oxygen content on hydrotreating requirements. The CFP oils with higher oxygen contents included a variety of oxygenates (phenols, methoxyphenols, carbonyls, anhydrosugars) whereas oxygenates in the 4 wt% oxygen oil were almost exclusively phenols. Phenols were the most recalcitrant oxygenates during hydrotreating as well, and the hydrotreated oils consisted mainly of aromatic and partially saturated ring hydrocarbons. The temperature required to produce oil with <1% oxygen was approximately 350 °C for the CFP oil with the lowest oxygen content whereas temperatures around 400 °C were required for the other CFP oils. The carbon efficiency during hydrotreating slightly decreased as the CFP oil oxygen content increased but remained above 90% in all cases, and the carbon efficiency for the integrated process was dominated by the efficiency of the CFP process. In conclusion, a preliminary technoeconomic evaluation suggested that with the current zeolite-based CFP catalysts, it is economically beneficial to preserve carbon during CFP, at the expense of higher oxygen contents in the CFP oil.},
doi = {10.1016/j.fuel.2017.06.098},
journal = {Fuel},
number = C,
volume = 207,
place = {United States},
year = 2017,
month = 6
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on June 29, 2018
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  • Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and themore » processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. As a result, the protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research.« less
  • We consider catalytic hydroprocessing of pyrolysis oils from biomass which produces hydrocarbons for liquid fuel production. This process requires removal of oxygen and cracking of the heavier molecular weight bio-oil constituents into smaller fragments at high temperatures and pressures under hydrogen. Here, we present in this paper the characterization of a group of five distillate fractions from each of two types of hydroprocessed oils from oak pyrolysis oil: a low oxygen content (LOC, 1.8% O, wet basis) oil and a medium oxygen content (MOC, 6.4% O, wet basis) oil. The LOC oil was generated using a sulfided hydrotreating system consistingmore » of RuS/C and xMoS/Al 2O 3 while the MOC was produced using non-sulfided catalysts, Ru/C and Pd/C. Elemental analysis and 13C NMR (nuclear magnetic resonance) results suggest that the distillate fractions from both oils become more aromatic/unsaturated as they become heavier. Carbonyl and carboxylic groups were found in the MOC light fractions, while phenols were present in the heavier fractions for both MOC and LOC. Paraffin, iso-paraffin, olefin, naphthene, aromatic (PIONA) analysis of the light LOC fraction shows a predominance of paraffins with a minor amount of olefins. Sulfur analysis showed the comparative concentration of sulfur in the different fractions as well as the surprising similarity in content in some sulfided and non-sulfided fractions. Our results can be used to direct future research on refinery integration and production of value-added product from specific upgraded oil streams.« less
  • Catalytic hydroprocessing of pyrolysis oils from biomass produces hydrocarbons that can be considered for liquid fuel production. This process requires removal of oxygen and cracking of the heavier molecular weight bio-oil constituents into smaller fragments at high temperatures and pressures under hydrogen. We present in this paper the characterization of a group of five distillate fractions from each of two types of hydroprocessed oils from oak pyrolysis oil: a low oxygen content (LOC, 1.8% O, wet basis) oil and a medium oxygen content (MOC, 6.4% O, wet basis) oil. The LOC oil was generated using a sulfided hydrotreating system consistingmore » of RuS/C and xMoS/Al2O3 while the MOC was produced using non-sulfided catalysts, Ru/C and Pd/C. Elemental analysis and 13C NMR (nuclear magnetic resonance) results suggest that the distillate fractions from both oils become more aromatic/unsaturated as they become heavier. Carbonyl and carboxylic groups were found in the MOC light fractions, while phenols were present in the heavier fractions for both MOC and LOC. Paraffin, iso-paraffin, olefin, naphthene, aromatic (PIONA) analysis of the light LOC fraction shows a predominance of paraffins with a minor amount of olefins. Sulfur analysis showed the comparative concentration of sulfur in the different fractions as well as the surprising similarity in content in some sulfided and non-sulfided fractions. These results can be used to direct future research on refinery integration and production of value-added product from specific upgraded oil streams.« less
  • Experimental methods for fast pyrolysis of lignocellulosic biomass to produce bio-oils and for the catalytic hydrotreating of bio-oils to produce fuel range hydrocarbons are presented. Hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil was also assessed. This is the first draft of our video publication for Jove. The manuscript is approved previously as PNNL-SA-108525. Please access the video via http://www.jove.com/video/54088?status=a56094k.
  • Catalytic hydroprocessing of pyrolysis oils from biomass produces hydrocarbons that can be considered for liquid fuel production. This process requires removal of oxygen and cracking of the heavier molecular weight bio-oil constituents into smaller fragments at high temperatures and pressures under hydrogen. A comprehensive understanding of product oils is useful to optimize cost versus degree of deoxygenation. Additionally, a better understanding of the chemical composition of the distillate fractions can open up other uses of upgraded oils for potentially higher-value chemical streams. We present in this paper the characterization data for five well-defined distillate fractions of two hydroprocessed oils withmore » different oxygen levels: a low oxygen content (LOC, 1.8% O, wet basis) oil and a medium oxygen content (MOC, 6.4% O, wet basis) oil. Elemental analysis and 13C NMR results suggest that the distillate fractions become more aromatic/unsaturated as they become heavier. Our results also show that the use of sulfided catalysts directly affects the S content of the lightest distillate fraction. Carbonyl and carboxylic groups were found in the MOC light fractions, while phenols were present in the heavier fractions for both MOC and LOC. PIONA analysis of the light LOC fraction shows a predominance of paraffins with a minor amount of olefins. These results can be used to direct future research on refinery integration and production of value-added product from specific upgraded oil streams.« less