
NSF Org: |
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems |
Recipient: |
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Initial Amendment Date: | August 2, 2018 |
Latest Amendment Date: | August 2, 2018 |
Award Number: | 1842101 |
Award Instrument: | Standard Grant |
Program Manager: |
Raymond Adomaitis
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems ENG Directorate for Engineering |
Start Date: | September 1, 2018 |
End Date: | August 31, 2020 (Estimated) |
Total Intended Award Amount: | $100,000.00 |
Total Awarded Amount to Date: | $100,000.00 |
Funds Obligated to Date: |
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History of Investigator: |
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Recipient Sponsored Research Office: |
220 PAWTUCKET ST STE 400 LOWELL MA US 01854-3573 (978)934-4170 |
Sponsor Congressional District: |
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Primary Place of Performance: |
Lowell MA US 01854-2827 |
Primary Place of
Performance Congressional District: |
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Unique Entity Identifier (UEI): |
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Parent UEI: |
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NSF Program(s): | Proc Sys, Reac Eng & Mol Therm |
Primary Program Source: |
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Program Reference Code(s): |
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Program Element Code(s): |
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Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.041 |
ABSTRACT
The development of economically viable techniques for manufacturing liquid transportation fuels from bio-oils produced by pyrolysis of lignocellulosic biomass is a grand challenge with important societal and environmental sustainability implications. One of the obstacles is the high hydrogen requirement for removing the undesired oxygen from the bio-oil via a chemical reaction called catalytic hydrodeoxygenation (HDO). On the other hand, recent developments in shale gas technologies have led to the production of vast amounts of under-utilized light alkanes, which could serve as a source hydrogen for bio-oil HDO. The main objective of this EAGER project is to explore the direct coupling reaction of bio-oil HDO and light (C2-C4) alkane dehydrogenation (DH) using a new family of bifunctional catalysts.
The central hypothesis of the proposed exploratory research is that an integrated catalyst design, consisting of a precious metal (e.g., Pt) and an oxophilic metal (e.g., Mo) on a low acidic and weak electronegative metal oxide support (e.g., TiO2), will enable the proposed reaction coupling scheme. Such a catalyst concept is theoretically possible, based on thermodynamic analysis, but has not been experimentally proven and remains untested. If successful, such a catalyst will radically transform the existing bio-oil upgrading and olefin production methods. Three specific research aims will be pursued to explore the feasibility of this concept: (1) the effect of metal site size and metal-metal site distance will be determined; (2) the influence of oxophilicity of the bio-oil HDO sites will be revealed; (3) the impact of support composition will be characterized. To obtain molecular-level understanding of the surface reaction pathways, the bifunctional catalysts will be synthesized with their structures controlled at the nanoscale. Catalyst activity will be measured based on the yields of desired and undesired products from the flow reactor experiments. The dependence of product distribution on (1) the size of the precious metal site, (2) the distance between the DH and HDO sites, (3) metal-oxygen bond strength of the oxophilic metal site, and (4) the compositions of the metal oxide support will be determined. The proposed exploratory research may lead to fundamental understanding of the catalytic geometric and electronic effects on the chemical kinetics of the surface reactions. In addition to training two graduate students, the principal investigators plan to integrate research outcomes into undergraduate and graduate curricula.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Key outcomes of this project include:
(1) During the copyrolysis of nitrobenzne and propane, the pyrolysis of propane was accelerated by phenyl radicals derived from nitrobenzene. Propylene yields were signficantly increased during copyrolysis despite slight decrease in its selectivity in favor of methane and ethylene.
(2) During the catalytic coupling of nitrobenzene (NB) hydrodeoxygenation (HDO) with ethylbenzene (EB) dehydrogenation (DH) over Mo/TiO2, NB and EB showed different adsorption rates on the TiO2 surfaces, resulting in higher NB conversion. In addition, three distinct reaction stages were identified on the MoO3 surfaces, each of which followed a different EB to NB stoichiometric ratio and was dependent on catalyst pretreatment by hydrogen and the amount of oxygen vacancies available on the surfaces.
(3) During the catalytic coupling of nitrobenzene (NB) hydrodeoxygenation (HDO) with propane dehydrogenation (DH) over Pt/Al2O3, the catalyst was found to cause little effect on propane DH with a small increase in propylene selectivity. However, the yields of NB HDO products were found to be signficantly increased.
(4) During the catalytic coupling of cresol or guaiacol hydrodeoxygenation (HDO) with propane dehydrogenation (DH), propane was found to have the potential to provide hydrogen for bio-oil HDO, although at a much lower efficiency than pure hydrogen gas. In addition, catalyst deactivation due to char formation on the catalyst surfaces was observed to be a major challenge and limiting factor.
(5) Our kinetic modeling work suggested that OH radicals, formed due to the presence of oxygen, are needed for activating C-H bonds of propane to promote propylene formation during the NOx-mediated parital oxidation of propane. The introduction of NO in the feed is believed to promote the formation of OH radicals from HO2 radicals during its conversion to NO2. The presence of steam (i.e., vapor phase H2O) shifts the equilibrium between OH and H2O and slows the quenching of OH radicals in the system. All these factors contribute to increased propylene yields during propane oxidation.
Last Modified: 01/02/2021
Modified by: Hsi-Wu Wong
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