HRTEM evaluation of primary soot particles originated in a small-bore biofuel compression-ignition engine. (August 2019)

• Record Type: Journal Article
• Authors: Hwang, Joonsik; Hirner, Felix Sebastian; Bae, Choongsik; Patel, Chetankumar; Gupta, Tarun; Agarwal, Avinash Kumar
• Is Part Of: Applied thermal engineering. Volume 159(2019)
• Publication Date: 2019-08
• Subjects: Transmission electron microscope (TEM) -- Soot particles -- Nano structure -- Soot reactivity -- Biodiesel -- Compression-ignition engine; aTDC after top dead center -- C carbon -- CAD crank angle degree -- DPF diesel particulate filter -- EA elemental analysis -- FFT fast Fourier transform -- HRTEM high-resolution transmission electron microscopy -- HC hydrocarbon -- IMEP indicated mean effective pressure -- LHV lower heating value -- O oxygen -- PM particulate matter -- ROI region of interest -- TGA thermo-gravimetric analysis -- VOF volatile organic fraction -- WCO waste cooking oil -- XRD X-ray diffraction; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2019.113899
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Biodiesel fuels showed higher particulate matter emissions than diesel fuel. High viscosity biodiesel fuels showed unburned hydrocarbon layer in primary particles. WCO biodiesel showed the smallest primary particle diameter among the tested fuels. Biodiesel fuels had larger fringe spacing compared to that of diesel. Abstract: Nanostructure of soot particles from a small-bore compression-ignition engine was investigated by high-resolution transmission electron microscopy (HRTEM). Four test fuels namely conventional diesel, waste cooking oil (WCO) biodiesel, Jatropha biodiesel, and Karanja biodiesel were studied. Lacey carbon TEM grids were utilized to capture soot particles from engine exhaust gas. An in-house image processing algorithm was developed to measure primary particle diameter, fringe length, fringe tortuosity, and fringe spacing. The HRTEM image revealed the presence of thicker absorbed hydrocarbon layers surrounding biodiesel soot primary particles than those of diesel soot. The primary particle size of WCO biodiesel was smaller than diesel, on the other hand, Jatropha biodiesel and Karanja biodiesel showed slightly larger particles. In terms of nano-structure analysis, WCO biodiesel and Jatropha biodiesel particles exhibited shorter fringe length than diesel, while the Karanja biodiesel particles showed the longest fringe length of 0.91 nm. Fringe tortuosity of biodiesels was smaller than diesel because of relatively lower portion of core area, where highly curved fringes existed. The soot particles from biodiesels exhibited larger fringe spacing than diesel, especially the Karanja biodiesel showed the longest fringe spacing of 0.67 nm compared to 0.55 nm in case of diesel.