Analysis of Soot from the Use of Butanol Blends in a Euro 6 Diesel Engine

Abstract

The use of advanced fuels must increase from 0.5 to 3.6 in internal combustion engines according to the forthcoming European directive. In this frame, alcohols that can be obtained from waste or lignocellulosic materials with advanced production techniques may play an important role in the future. This work focuses on the effect of the use of butanol as a blend component on the properties of soot emmited from compression ignition engines. This knowledge is essential to decide the strategy to carry out a proper regeneration process in the Diesel Particle Filter (DPF). The study was performed in a Euro 6 diesel engine. The engine operating condition used to collect particulate matter was selected as a typical steady mode in urban driving. The blends tested were baseline diesel, Bu10D (10% butanol and 90% diesel v/v), Bu20D (20% butanol and 80% diesel v/v) and Bu10B10D (10% butanol, 10% biodiesel and 80% diesel v/v). The techniques used to characterise the soot are X-Ray Difraction (XRD), Raman spectroscopy, Transmission Electron Microscopy (TEM), surface area analyser, X-ray Photoelectron Spectroscopy (XPS), Fourier-Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). From the results shown, the average primary particle diameter, which is reduced for increasing butanol content, provided the best consistency with soot reactivity obtained from TGA and DSC.

Impact of n-Hexanol Blending on Morphology, Nanostructure, Graphitization, and Oxidation Characteristics of Diesel Particles

“…Similar results have been reported in previous studies. 29,30,71 Li et al 71 investigated the soot morphology in a laminar diffusion flame fueled with n-heptane, n-butanol, and H50B50 (50% n-heptane and 50% n-butanol, v/v), respectively. Their results showed that as the n-butanol content in blended fuels increased, smaller aggregates and primary particles were produced.…”

“…49 The D3 band is a representation of the vibration of the amorphous carbon. 29 Correspondingly, I D1 /I G (intensity ratio of the D1 band to the G band) and A D1 /A G (area ratio of the D1 band to the G band) are used to represent the degree of graphitization and the degree of disorder for particles, respectively. The higher the value of I D1 /I G is, the lower the degree of graphitization is.…”

“…This behavior can be explained by that the oxygen of n-hexanol promoted particle oxidation in the cylinder and consequently decreased primary particle size. Such particles with a smaller diameter had a larger surface/volume ratio (relative surface area) 29 and thus promoted the absorption of hydrocarbons, which contributed to high VOF. On the other hand, as for the effect of engine speed on the distributions of two compositions, results showed that the proportion of nonvolatile substances in particulates sampled at high engine speed was lower, while VOF was higher, in comparison with particulates sampled at low engine speed.…”

“…Conversely, Verma et al 30 reported that as the butanol content increased, the fractal dimension of exhaust particles increased, while the fringe separation distance decreased. Lapuerta et al 29 observed by transmission electron microcopy (TEM) that as the proportion of butanol increased from 0 to 20%, the mean primary particle diameter and interplanar distance decreased, while the fringe length and tortuosity increased. Determined by X-ray photoelectron spectroscopy (XPS), oxygenated functional groups including hydroxyl, carboxyl, and carbonyl increased when the butanol content increased, meaning a higher soot reactivity of diesel/butanol particulates.…”

Improved Performance, Combustion and Emissions of SI Engine Fuelled with Butanol: A Review

“…Regulations on PM emission are imposed stricter in diesel engines [120][121][122]. In gasoline engines, however, laws and protocols have not been set up for PM emission.…”