Multi-Technique Analysis of Soot Reactivity from Conventional and Paraffinic Diesel Fuels

Lapuerta, Magı́n; Rodríguez–Fernández, José; Sánchez-Valdepeñas, Jesús; Salgado, Sagrario

doi:10.1007/s10494-015-9644-y

Cited by 32 publications

(15 citation statements)

References 44 publications

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“…The concentration of hydroxyl groups (peaks at ~3100-3500 cm -1 ) [11] is also more apparent for the CNG70 case. The peak at ~2909 cm -1 is characteristic of the C-H vibrations of saturated hydrocarbons, indicating the presence of sp 3 hybridized carbon, which is related to the graphitic structure of soot [9,20].…”

Section: Driftsmentioning

confidence: 85%

“…These two bands correspond to C=O (1660-1750 cm -1 ) and C-O (1120-1220 cm -1 ) stretching of carboxylic acids [12,20,27]. The increasing sharpness of the peak at ~1740 cm -1 as CNG content increases, suggests a higher degree of oxygen functionality for CNG soot [11,27].…”

Section: Raman Spectroscopymentioning

confidence: 96%

“…Finally, it has been suggested that higher soot reactivity is related to the concentration of hydroxyl groups [11]. As such, CNG soot satisfies all the above criteria, which explains its higher reactivity.…”

Section: Driftsmentioning

confidence: 98%

“…Diesel soot generally takes the form of larger aggregates composed principally of smaller spherical particles called spherules and possessing characteristic structural properties. The nanostructure of soot depends strongly on the initial fuel identity and synthesis conditions, such as burning temperature, residence time, fuel properties, and fuel/oxygen ratio; the nanostructure in turn affects the oxidation reactivity of the soot [9][10][11][12][13][14]. Therefore, characterizing the physicochemical characteristics of soot is important and can provide crucial information to improve the design and operation of after-treatment systems.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, characterizing the physicochemical characteristics of soot is important and can provide crucial information to improve the design and operation of after-treatment systems. Common methods used to analyze soot structure and chemical properties are Transmission Electron Microscopy (TEM) [15][16][17][18][19][20][21], Thermogravimetric Analysis (TGA) Spectroscopy (DRIFTS) [9,11,21,22]. Although soot morphology and nanostructure have been widely studied for other alternative fuels such as crude vegetable oil [9] and biodiesels [10,11], there are no studies that have compared PM from diesel and diesel/CNG dual-fuel combustion.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of soot from diesel-CNG dual-fuel combustion in a CI engine

Nithyanandan

Lin

Donahue

et al. 2016

Fuel

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The physico-chemical characterization of exhaust soot is very important in the design and operation of suitable after-treatment systems. The nanostructure and reactivity of soot depends strongly on the initial fuel identity and synthesis conditions. This paper presents the chemical composition, oxidation reactivity and nanostructural characteristics of particulate matter (PM) produced by a diesel engine operating with diesel/compressed natural gas (CNG) dual-fuel combustion. Raw, undiluted soot samples from pure diesel, 40% CNG and 70% CNG (energy-based substitution rate) combustion were collected from the exhaust pipe. Engine operation conditions were held at 1200 RPM and 20 mg/cycle baseline load. For dual-fuel operation, split diesel injection (two injections) was used as the pilot. CNG was injected into the intake manifold. First, soot oxidation reactivity was characterized using thermogravimetric analysis (TGA). Transmission electron microscopy (TEM) was then used to determine the diameter of the spherules, and the morphology of agglomerates. Raman spectroscopy was employed to determine the graphitic nature of the soot. Finally, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to identify surface functional groups of soot samples. It was found that soot reactivity increased with increasing CNG content. TEM images revealed a higher variation in particle diameter with increasing CNG substitution. High resolution TEM (HRTEM) images showed that CNG70 soot displayed features of immature soot particles. Raman spectroscopy results showed that soot reactivity does not depend on the initial graphitic structure. DRIFTS showed increased concentration of aliphatic and oxygen functional groups, which explained the higher reactivity. This enhanced reactivity could also be due to more active sites available in CNG soot, as well as due to CNG soot being immature. Under this test condition and engine configuration, it can be concluded that the use of CNG affects the morphology and nanostructure of PM, and hence the oxidation reactivity of the soot.

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Section: Driftsmentioning

confidence: 85%

Section: Raman Spectroscopymentioning

confidence: 96%

Section: Driftsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterization of soot from diesel-CNG dual-fuel combustion in a CI engine

Nithyanandan

Lin

Donahue

et al. 2016

Fuel

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Parffinic Biofuels: HVO, BTL Diesel, and Farnesane

2019

Application of Liquid Biofuels to Internal Combustion Engines

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Chemical characterization of diesel and hydrotreated vegetable oil (HVO) soot after reactive gas probing using diffuse reflectance FTIR spectroscopy (DRIFTS)

Tapia

Salgado

Martín

et al. 2017

Environ Sci Pollut Res

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A chemical characterization of diesel and hydrotreated vegetable oil (HVO) soot has been developed using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) before and after the reaction with different probe gases. Samples were generated under combustion conditions corresponding to an urban operation mode of a diesel engine and were reacted with probe gas-phase molecules in a Knudsen flow reactor. Specifically, NHOH, O and NO were used as reactants (probes) and selected according to their reactivities towards specific functional groups on the sample surface. Samples of previously ground soot were diluted with KBr and were introduced in a DRIFTS accessory. A comparison between unreacted and reacted soot samples was made in order to establish chemical changes on the soot surface upon reaction. It was concluded that the interface of diesel and HVO soot before reaction mainly consists polycyclic aromatic hydrocarbons, nitro and carbonyl compounds, as well as ether functionalities. The main difference between both soot samples was observed in the band of the C=O groups that in diesel soot was observed at 1719 cm but not in HVO soot. After reaction with probe gases, it was found that nitro compounds remain on the soot surface, that the degree of unsaturation decreases for reacted samples, and that new spectral bands such as hydroxyl groups are observed.

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Multi-Technique Analysis of Soot Reactivity from Conventional and Paraffinic Diesel Fuels

Cited by 32 publications

References 44 publications

Characterization of soot from diesel-CNG dual-fuel combustion in a CI engine

Characterization of soot from diesel-CNG dual-fuel combustion in a CI engine

Parffinic Biofuels: HVO, BTL Diesel, and Farnesane

Chemical characterization of diesel and hydrotreated vegetable oil (HVO) soot after reactive gas probing using diffuse reflectance FTIR spectroscopy (DRIFTS)

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