10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Effect of Acetone-Butanol-Ethanol (ABE) Addition to Diesel on the Soot Formation and Soot Reactivity
JIANFEI LUO, Yongming Zhang, Qixing Zhang, University of Science and Technology of China
Abstract Number: 641 Working Group: Combustion
Abstract Soot particles from vehicles, especially diesel vehicles is a significant contributor to atmospheric PM2.5, it is very necessary to increase the adoption of oxygenated fuels as alternative fuels to reduce pollutant emissions.Acetone-Butanol-Ethanol (ABE), the intermediate product in bio-butanol production process using biological fermentation purification technology, has been proposed to blend diesel directly for saving the high energy requirement of separating purity butanol. Literature has shown that ABE has a similar combustion characteristics in engine compared to petroleum diesel. This work aims at understanding the soot formation in ABE-diesel blends diffusion flame, and the oxidation reactivity of ABE-diesel blends derived soot.
The Threshold Sooting Index (TSI) calculated from fuel consumption rate and smoke point were used to evaluate the sooting tendency of ABE-diesel blends. And the results indicated that the normalized TSI showed a cutting down exponent trend with increasing concentration of ABE in diesel, embodying the emission reduction capacity of ABE. To reveal the inhibitory nature of soot formation in ABE blends flame. Toluene and heptane were selected as model alternative fuels for diesel to establish the ABE blends chemical reaction mechanism. The laminar premixed flame structure of ABE-toluene-heptane blends were calculated through CHEMKIN Pro. It was found that the concentration of toluene were diluted in premixed zone and were consumed ahead of high temperature zone, thus the concentration of soot precursors such as polycyclic aromatic hydrocarbons (PAHs) produced in the presence of toluene were decreased. The amplification effect of smaller PAHs polymerization reaction further reduced the larger PAHs generation rate. In addition, the increased HO2 and OH concentration by ABE accelerated the oxidation consumption of PAHs.
To characterize the oxidation reactivity and physicochemical properties of ABE-diesel blends derived soot. Several diagnostic experimental technologies such as Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and high resolution transmission electron microscopy (HRTEM) have been used. It was observed that the average activation energies of ABE-diesel blends derived soot were lower than diesel derived soot. And the variation in the sizes of primary particles, fringe length, fringe tortuosity, the amount of functional groups, atomic O/C ratio, and H/C ratio support the higher oxidative reactivity of ABE-diesel blends derived soot.