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In the present work, a digital image processing (DIP) method was developed to measure the residence time distribution (RTD) in a plasticating extruder. The DIP method is off‐line, but it consumes less time and yields more data than the traditional off‐line ones, and it avoids the expensive probes and data acquisition systems that are necessary in the on‐line and in‐line measurements. The correctness of the DIP method was validated by a comparative experiment using silica powder as the tracer. A locally made Buss Kneader equipped with a gear pump system was used herein. The effects of the operating conditions on the RTD in this equipment were also studied. Furthermore, the relationship between the mean residence time and the operating conditions was analyzed. POLYM. ENG. SCI., 47:1108–1113, 2007. © 2007 Society of Plastics Engineers

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.

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