Abstract
Bioderived ethers have recently drawn attention as a response to increasing demands for clean alternative fuels. A theory-experiment combined approach was introduced for five ether molecules representing linear, branched, and cyclic ethers to derive rational design principles for low-emission and high-reactivity ethers. Flow reactor experiments and quantum-mechanical calculations were performed at high- (750-1100 K) and low-temperature (400-700 K) regimes to investigate the structural effects on their sooting tendency and reactivity, respectively. At high-temperatures, the high-sooting tendency of ethers is related to increased C3 and C4 hydrocarbon formation compared to C1 and C2 products from oxidation reactions. On the other hand, the reactivity in the low-temperature regime is determined by the activation energies of reaction steps leading to ketohydroperoxide formation. These studies found that the sooting tendency and reactivity of ethers are relevant to two structural factors: the carbon type (primary to quaternary) and the relative position of ether oxygen atoms to carbon atoms. These factors were utilized to build a multivariate regression model, fitted to the cetane number (CN) and yield sooting index (YSI) of 50 different ethers. The model suggests building blocks with specific carbon types that maximize the CN and minimize the YSI, leading to design principles for ethers having low-emissions and high-reactivity as fuels for transport applications. Ethers with a high CN and low YSI were then proposed using the developed model, and through experimental measurements, it was demonstrated that they are promising biodiesel candidates.
| Original language | English |
|---|---|
| Pages (from-to) | 3975-3988 |
| Number of pages | 14 |
| Journal | Sustainable Energy and Fuels |
| Volume | 6 |
| Issue number | 17 |
| DOIs | |
| State | Published - Jul 18 2022 |
| Externally published | Yes |
Funding
This research was conducted as part of the Co-Optimization of Fuels & Engines (Co-Optima) project sponsored by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy Bioenergy Technologies Office and Vehicle Technologies Office. Co-Optima is a collaborative project of several national laboratories initiated to simultaneously accelerate the introduction of affordable, scalable, and sustainable biofuels and high-efficiency, low-emission vehicle engines. Work at the National Renewable Energy Laboratory was performed under Contract No. DE347AC36-99GO10337. The work at Yale was based upon subcontract DE-A36-08GO28308 from the Alliance for Sustainable Energy, LLC, Managing and Operating Contractor for the National Renewable Energy Laboratory for DOE. A portion of this research was performed using computational resources sponsored by the Department of Energy's Office of Energy Efficiency and Renewable Energy and located at the National Renewable Energy Laboratory. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. Computer time was provided by the NSF Extreme Science and Engineering Discovery Environment (XSEDE), Grant no. TG-CHE210034 and by the National Renewable Energy Laboratory Computational Science Center.