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

Abstract

As a promising alternative fuel with favorable properties and attractive prospects, the application of n-hexanol in diesel engines has aroused the interest of researchers. This study investigated the effects of mixing with n-hexanol on the morphology, nanostructure, graphitization, and oxidation reactivity of soot particles generated from a diesel engine. Experiments were performed on a turbocharged, four-cylinder direct-injection diesel engine fueled with D100 (neat diesel fuel), DH15 (15% nhexanol and 85% diesel, v/v), and DH30 (30% n-hexanol and 70% diesel, v/v), respectively. Under the constant torque of 125 N•m, two typical speeds of 1370 and 2150 rpm were selected. Transmission electron microscopy (TEM), Raman spectroscopy (RS), and thermogravimetric analysis (TGA) were used to characterize particulate samples. TEM images showed that DH15 and DH30 particles had smaller primary particle diameters in comparison with neat diesel particles. Moreover, with the increase of the nhexanol content in mixtures, the interlayer distance increased, indicating a more disordered nanostructure. RS results showed that soot samples generated from n-hexanol/diesel blended fuels had a lower degree of graphitization with larger I D1 /I G and A D1 /A G and more amorphous carbon with larger I D3 /I G and A D3 /A G . Based on TGA, it can be deduced that the DH30 soot sample obtained at the engine speed of 1370 rpm was easier to be oxidized in the DPF regeneration process for an 8.23% reduction in T max compared with D100 soot. Furthermore, activation energy of soots sampled at the engine speed of 2150 rpm decreased from 123.0 kJ/mol for D100 soot, to 109.6 kJ/mol for DH15 soot, and to 101.2 kJ/mol for DH30 soot, respectively. Regarding the effect of engine speeds on physicochemical characteristics of particles, results showed that the soot has higher oxidation activity under higher engine speed.

Optimizing Silver Paste Conductivity with Controlled Convection for Nanowrinkle Growth

“…The sintering process of silver powder can be roughly divided into two processes: the removal of organic matter and the densification of silver powder. In the removal stage of organic matter, the primary component of the organic carrier, n -hexanol, is rapidly removed at 157 °C . The removal temperature of the surface-modified organic matter of the wrinkled silver powder and the smooth silver powder is around 230 °C (Figure a,b).…”

“…In the removal stage of organic matter, the primary component of the organic carrier, n-hexanol, is rapidly removed at 157 °C. 36 The removal temperature of the surface-modified organic matter of the wrinkled silver powder and the smooth silver powder is around 230 °C (Figure 8a,b). Therefore, the organic carrier is preferentially removed, and it is the surfactant remaining on the surface of the silver powder that determines the start of sintering.…”

Morphological characterization of soot from a compression ignition engine fueled with diesel and an oxygenated fuel

“…Relatively more reactive soot would result in slower accumulation inside the filter and also faster filter regeneration. 15,16 In an investigation related to oxygenated fuel, Wang et al 17 investigated 15% and 30% v/v blend of n-hexanol with diesel at 125 Nm engine load. With increase in hexanol ratio, authors reported relatively lower degree of graphitization.…”