Nanostructure and Oxidation Reactivity of Nascent Soot Particles in Ethylene/Pentanol Flames

Abstract

Abstract:As byproducts of the combustion process of hydrocarbon fuels, soot particles are difficult to remove, and they can greatly harm human health and pollute the environment. Therefore, the formation and growth processes of the soot particles has become a study focus of researchers. In this paper, the nanostructure and oxidation reactivity of carbonaceous particles collected from ethylene inverse diffusion flames with or without the additions of three pentanol isomers (1-pentanol, 3-methyl-1-butanol, and 2-methyl-1-butanol) were investigated in detail. The nanostructure and oxidation characteristics of nascent soot particles were characterized using high resolution transmission electron microscopy (HRTEM), X-ray diffractometry (XRD) and thermogravimetric analysis (TGA). It was found that the nascent soot cluster of pure ethylene flame had a loose structure, while the additions of pentanol isomers made the soot agglomerates more compact and delayed the growth of graphitic structures. The pentanol isomer additions also contributed to a higher disorder of the crystallite arrangement in the soot nanostructure. According to the TGA experiments, the results showed that the addition of pentanol isomers enhanced the oxidation reactivity of soot particles, which could help to reduce soot particle emissions.

On the Response of Nascent Soot Nanostructure and Oxidative Reactivity to Photoflash Exposure

“…The HRTEM image processing was performed by homemade MATLAB analysis algorithms. The method is similar to the ones developed by Yehliu et al [25,26] and Ying et al [9,10]. The image processing involves several operations such as negative transformation, region of interest selection, contrast enhancement, Gaussian low pass filter, top-hat transformation, thresholding to obtain a binary image, morphological modification, skeletonization, and short fringes and boundary fringes removal.…”

“…Soot nanostructure impacts soot oxidation reactivity and has been widely studied [8][9][10][11]. Vander Wal et al [12] investigated the dependence of soot oxidation rate upon the nanostructure including fringe length, curvature and separation distance of the carbon layers.…”

Nanoscale Characteristics and Reactivity of Nascent Soot from n-Heptane/2,5-Dimethylfuran Inverse Diffusion Flames with/without Magnetic Fields

“…The test uncertainty was ±5% error which derived from a set of isothermal oxidation experiments. Two separate experiments were carried out to verify the reproducibility of the TGA results [21,22,64].…”

“…The instrument with scan range of 10-110 • was used at scan step size of 0.02 • and scan speed of 0.2 s/step [22,64].…”

“…Oh et al [20] performed experimental measurements of flame structure and soot characteristics of diluted ethane IDF by changing the fuel dilution ratio and air/fuel ratio and found that soot inception and growth were weakly dependent on temperature as influenced by fuel dilution. Ying et al [21,22] studied the nanostructure and oxidation reactivity of soot in ethylene IDF and NDF with butanol isomers and pentanol additions and compared the effects of the butanol isomers on the physical and chemical properties of soot. The effects of oxygen on soot production had been studied in recent years.…”