In situ temperature measurements in sooting methane/air flames using synchrotron x-ray fluorescence of seeded krypton atoms.

Synchrotron x-ray fluorescence has been used to measure temperatures in optically dense gases where traditional methods would fail. These data provide a benchmark for stringent tests of computational fluid dynamics models for complex systems where physical and chemical processes are intimately linked. The experiments measured krypton number densities in a sooting, atmospheric pressure, nonpremixed coflow flame that is widely used in combustion research.

Reactive Molecular Dynamics Simulations and Quantum Chemistry Calculations To Investigate Soot-Relevant Reaction Pathways for Hexylamine Isomers.

Sooting tendencies of a series of nitrogen-containing hydrocarbons (NHCs) have been recently characterized experimentally using the yield sooting index (YSI) methodology. This work aims to identify soot-relevant reaction pathways for three selected CHN amines, namely, dipropylamine (DPA), diisopropylamine (DIPA), and 3,3-dimethylbutylamine (DMBA) using ReaxFF molecular dynamics (MD) simulations and quantum mechanical (QM) calculations and to interpret the experimentally observed trends. ReaxFF MD simulations are performed to determine the important intermediate species and radicals involved in the fuel decomposition and soot formation processes.

Performance-advantaged ether diesel bioblendstock production by a priori design.

Lignocellulosic biomass offers a renewable carbon source which can be anaerobically digested to produce short-chain carboxylic acids. Here, we assess fuel properties of oxygenates accessible from catalytic upgrading of these acids a priori for their potential to serve as diesel bioblendstocks. Ethers derived from C and C carboxylic acids are identified as advantaged fuel candidates with significantly improved ignition quality (>56% cetane number increase) and reduced sooting (>86% yield sooting index reduction) when compared to commercial petrodiesel.

Sooting tendencies of oxygenated hydrocarbons in laboratory-scale flames.

Sooting tendencies have been measured for 186 oxygenated and 89 regular hydrocarbons under controlled laboratory conditions. The test compounds include alcohols, ethers, aldehydes, ketones, esters, alkanes, alkenes, and cycloalkanes ranging in size from methanol to isododecane. Sooting tendency was characterized with a new method based on measuring particle concentrations in methane/air nonpremixed flames when 1000 ppm of each test compound was added to the fuel.

Decomposition and hydrocarbon growth processes for esters in non-premixed flames.

Biomass fuels are a promising renewable energy source, and so, the mechanisms that may produce toxic oxygenated byproducts and aromatic hydrocarbons from oxygenated hydrocarbons are of interest. Esters have the form R-(C=O)-O-R' and are components of biodiesel fuels. The five specific esters studied here are isomers of C5H10O2.