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Title: Improved Hydrogen Utilization and Carbon Recovery for Higher Efficiency Thermochemical Bio-oil Pathways

Abstract

The goal of this project was to develop a novel integrated direct biomass liquefaction process with improved hydrogen utilization and better carbon efficiency compared to other thermochemical conversion technologies for advanced biofuels production. Reactive catalytic fast pyrolysis, or RCFP, combines a robust hydrodeoxygenation catalyst for in situ pyrolysis in an excess of hydrogen at atmospheric (low) pressure. RCFP was developed to leverage advantages from catalytic fast pyrolysis (process simplicity and improved bio-crude quality) and biomass hydropyrolysis (enhanced hydrodeoxygenation) to produce a thermally-stable, low oxygen containing bio-crude intermediate that can be upgraded in a single conventional hydroprocessing step to produce gasoline- and diesel-range hydrocarbons. In parallel, carbon lost to the aqueous phase was recovered as renewable methane from anaerobic digestion to offset fossil carbon required to meet the hydrogen demand of the integrated process. A total of 12-L (9.0 kg) of RCFP bio-crude was also hydrotreated continuously for 144 hours in RTI’s pilot-scale hydroprocessing unit at 2000 psig hydrogen pressure, space velocity of 0.35 h-1, and an average reactor bed temperature of 300 °C. Hydrotreating catalyst deactivation was evident as the product density increased gradually from 0.852 kg/L at TOS of 13 h to 0.955 kg/L at 144 h. The oxygenmore » content of the liquid product was 1.4 wt% at TOS 13 h and slowly increased to 5.5wt% by TOS 144 h. The concentration of naphthenic hydrocarbons and mono-aromatics decreased with time as the concentration of simple phenols, di-aromatics, PAH, and multifunctional phenolics increased. In parallel to the RCFP development, an AnMBR was operated nearly continuously from May 2015 through June 2019 to demonstrate the production of renewable methane from the anaerobic digestion of aqueous phase carbon. During this time, process modifications were regularly implemented to enhance methane production to its highest potential as the concentration of the CFP aqueous phase was steadily increased. By the end of the project, 5 vol% of neutralized CFP aqueous phase was being fed into the AnMBR with a nutritious component to support biomass growth. The overall COD removal was as high as 92% while the maximum specific methane conversion was 400 L CH4/kg COD. The AnMBR system showed the best performance when the biofuel wastewater portion was 3 – 3.5% in terms of methane production. Adaptation of the microbial community in the anaerobic digester played a very large role in improving carbon conversion efficiency and methane production. An Aspen Plus process model was developed to simulate an integrated 2000 tonne/day nth plant biorefinery for advanced biofuel production that includes unit operations for feedstock preparation, reactive catalytic biomass pyrolysis, bio-crude upgrading, aqueous phase carbon recovery, and hydrogen production. Highlights: • 43% carbon efficiency for loblolly pine RCFP using a reduced Mo-based catalyst at 450°C in 80 vol% hydrogen • Liquid RCFP bio-crude with 6 wt% oxygen. • 15-L of RCFP bio-crude produced for upgrading • 3-L of RCFP bio-crude co-processed with light gas oil for 1000 hours reducing HDS activity by only 40%. • 12-L of RCFP bio-crude was hydrotreated continuously for 144 hours without any major issues; there was no pressure drop across the reactor. • AnMBR was operated nearly continuously from May 2015 through June 2019 to demonstrate the production of renewable methane from the anaerobic digestion of aqueous phase carbon. • The overall COD removal was as high as 92% while the maximum specific methane conversion was 400 L CH4/kg COD. • The minimum fuel selling price of advanced biofuel produced for the integrated RCFP process with $40/ton feedstock costs on a dry basis is $3.27/gal of C4+ hydrocarbons.« less

Authors:
ORCiD logo [1]
  1. RTI International, Research Triangle Park, NC (United States)
Publication Date:
Research Org.:
RTI International, Research Triangle Park, NC (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Bioenergy Technologies Office
Contributing Org.:
Haldor Topsoe; Veolia Water Solutions
OSTI Identifier:
1798873
Report Number(s):
DOE-RTI-6636-1
DOE Contract Number:  
EE0006636
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; reactive catalytic biomass pyrolysis, RCFP, anaerobic digestion, hydrotreating, biocrude upgrading

Citation Formats

Dayton, David. Improved Hydrogen Utilization and Carbon Recovery for Higher Efficiency Thermochemical Bio-oil Pathways. United States: N. p., 2021. Web. doi:10.2172/1798873.
Dayton, David. Improved Hydrogen Utilization and Carbon Recovery for Higher Efficiency Thermochemical Bio-oil Pathways. United States. https://doi.org/10.2172/1798873
Dayton, David. 2021. "Improved Hydrogen Utilization and Carbon Recovery for Higher Efficiency Thermochemical Bio-oil Pathways". United States. https://doi.org/10.2172/1798873. https://www.osti.gov/servlets/purl/1798873.
@article{osti_1798873,
title = {Improved Hydrogen Utilization and Carbon Recovery for Higher Efficiency Thermochemical Bio-oil Pathways},
author = {Dayton, David},
abstractNote = {The goal of this project was to develop a novel integrated direct biomass liquefaction process with improved hydrogen utilization and better carbon efficiency compared to other thermochemical conversion technologies for advanced biofuels production. Reactive catalytic fast pyrolysis, or RCFP, combines a robust hydrodeoxygenation catalyst for in situ pyrolysis in an excess of hydrogen at atmospheric (low) pressure. RCFP was developed to leverage advantages from catalytic fast pyrolysis (process simplicity and improved bio-crude quality) and biomass hydropyrolysis (enhanced hydrodeoxygenation) to produce a thermally-stable, low oxygen containing bio-crude intermediate that can be upgraded in a single conventional hydroprocessing step to produce gasoline- and diesel-range hydrocarbons. In parallel, carbon lost to the aqueous phase was recovered as renewable methane from anaerobic digestion to offset fossil carbon required to meet the hydrogen demand of the integrated process. A total of 12-L (9.0 kg) of RCFP bio-crude was also hydrotreated continuously for 144 hours in RTI’s pilot-scale hydroprocessing unit at 2000 psig hydrogen pressure, space velocity of 0.35 h-1, and an average reactor bed temperature of 300 °C. Hydrotreating catalyst deactivation was evident as the product density increased gradually from 0.852 kg/L at TOS of 13 h to 0.955 kg/L at 144 h. The oxygen content of the liquid product was 1.4 wt% at TOS 13 h and slowly increased to 5.5wt% by TOS 144 h. The concentration of naphthenic hydrocarbons and mono-aromatics decreased with time as the concentration of simple phenols, di-aromatics, PAH, and multifunctional phenolics increased. In parallel to the RCFP development, an AnMBR was operated nearly continuously from May 2015 through June 2019 to demonstrate the production of renewable methane from the anaerobic digestion of aqueous phase carbon. During this time, process modifications were regularly implemented to enhance methane production to its highest potential as the concentration of the CFP aqueous phase was steadily increased. By the end of the project, 5 vol% of neutralized CFP aqueous phase was being fed into the AnMBR with a nutritious component to support biomass growth. The overall COD removal was as high as 92% while the maximum specific methane conversion was 400 L CH4/kg COD. The AnMBR system showed the best performance when the biofuel wastewater portion was 3 – 3.5% in terms of methane production. Adaptation of the microbial community in the anaerobic digester played a very large role in improving carbon conversion efficiency and methane production. An Aspen Plus process model was developed to simulate an integrated 2000 tonne/day nth plant biorefinery for advanced biofuel production that includes unit operations for feedstock preparation, reactive catalytic biomass pyrolysis, bio-crude upgrading, aqueous phase carbon recovery, and hydrogen production. Highlights: • 43% carbon efficiency for loblolly pine RCFP using a reduced Mo-based catalyst at 450°C in 80 vol% hydrogen • Liquid RCFP bio-crude with 6 wt% oxygen. • 15-L of RCFP bio-crude produced for upgrading • 3-L of RCFP bio-crude co-processed with light gas oil for 1000 hours reducing HDS activity by only 40%. • 12-L of RCFP bio-crude was hydrotreated continuously for 144 hours without any major issues; there was no pressure drop across the reactor. • AnMBR was operated nearly continuously from May 2015 through June 2019 to demonstrate the production of renewable methane from the anaerobic digestion of aqueous phase carbon. • The overall COD removal was as high as 92% while the maximum specific methane conversion was 400 L CH4/kg COD. • The minimum fuel selling price of advanced biofuel produced for the integrated RCFP process with $40/ton feedstock costs on a dry basis is $3.27/gal of C4+ hydrocarbons.},
doi = {10.2172/1798873},
url = {https://www.osti.gov/biblio/1798873}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2021},
month = {6}
}