Molecular Aluminum Additive for Burn Enhancement of Hydrocarbon Fuels.
Additives to hydrocarbon fuels are commonly explored to change the combustion dynamics, chemical distribution, and/or product integrity. Here we employ a novel aluminum-based molecular additive, Al(I) tetrameric cluster [AlBrNEt3]4 (Et = C2H5), to a hydrocarbon fuel and evaluate the resultant single-droplet combustion properties. This Al4 cluster offers a soluble alternative to nanoscale particulate additives that have recently been explored and may mitigate the observed problems of particle aggregation. Results show the [AlBrNEt3]4 additive to increase the burn rate constant of a toluene-diethyl ether fuel mixture by ∼20% in a room temperature oxygen environment with only 39 mM of active aluminum additive (0.16 wt % limited by additive solubility). In comparison, a roughly similar addition of nano-aluminum particulate shows no discernible difference in burn properties of the hydrocarbon fuel. High speed video shows the [AlBrNEt3]4 to induce microexplosive gas release events during the last ∼30% of the droplet combustion time. We attribute this to HBr gas release based on results of temperature-programmed reaction (TPR) experiments of the [AlBrNEt3]4 dosed with O2 and D2O. A possible mechanism of burn rate enhancement is presented that is consistent with microexplosion observations and TPR results.
University of Maryland, College Park, Maryland 20740, United States.
Philip M
PM
Guerieri
University of Maryland, College Park, Maryland 20740, United States.
Samantha
S
DeCarlo
University of Maryland, College Park, Maryland 20740, United States.
Bryan
B
Eichhorn
The Pennsylvania State University, University Park, Pennsylvania 16801, United States.
Terrence
T
Connell
The Pennsylvania State University, University Park, Pennsylvania 16801, United States.
Richard A
RA
Yetter
Johns Hopkins University, Baltimore, Maryland 21218, United States.
Xin
X
Tang
Johns Hopkins University, Baltimore, Maryland 21218, United States.
Zachary
Z
Hicks
Johns Hopkins University, Baltimore, Maryland 21218, United States.
Kit H
KH
Bowen
University of Maryland, College Park, Maryland 20740, United States.
Michael R
MR
Zachariah