Characterization of Exhaust Particulates from a Dual Fuel Engine by TGA, XPS, and Raman Techniques

Mustafi, Nirendra N.; Raine, Robert R.; James, Bryony

doi:10.1080/02786826.2010.503668

Cited by 46 publications

(22 citation statements)

References 36 publications

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“…Strategies to reduce PM (reviewed below) resemble those used for conventional diesel engines. In contrast, "dual-fuel" or "fumigated" engines use late-cycle diesel injections (Wong et al 1991;Mustafi et al 2010) to ignite natural gas that is mixed with the intake air. In fumigated engines, soot emissions are almost entirely due to the diesel fuel, while the premixed charge gives rise to NOx, CO, and HC emissions resembling those of spark-ignited engines.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Particulate Matter Morphology and Volatility from a Compression-Ignition Natural-Gas Direct-Injection Engine

Graves

Olfert

Patychuk³

et al. 2015

Aerosol Science and Technology

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The particulate matter (PM) emitted from a single-cylinder compression-ignition, natural-gas engine fitted with a HighPressure Direct-Injection (HPDI) system distinctly different from a duel fuel engine was investigated, and characterized by size distribution, morphology, mass-mobility exponent, effective density, volatility, mixing state, and primary particle size using transmission electron microscopy (TEM), and tandem measurements from differential mobility analyzers (DMA) and a centrifugal particle mass analyzer (CPMA). Six engine conditions were selected with varying load, speed, exhaust gas recirculation (EGR) fraction, and fuel delivery strategy. An increase in engine load increased both the number concentration and the geometric mean diameter of the particulate. The fraction of the number of purely volatile particles to total number of particles (number volatile fraction, NVF) was found to decrease as load increased, although at the lower speed, partially premixed mode, the lowest NVF. All size distributions were also found to be unimodal. The size-segregated ratio of the mass of internally mixed volatile material to total particle mass (mass volatile fraction, MVF) decreased with load and with particle mobility-equivalent diameter. A roughly constant amount of volatile material is likely produced at each engine mode, and the decrease in MVF is due to the increase in PM number with load. Effective density and massmobility exponent of the non-volatile soot at the different engine loads were the same or slightly higher than soot from traditional diesel engines. Denuded effective density trends were observed to collapse to approximately the same line, although engine modes with higher MVFs had slightly higher effective densities suggesting that the soot structures have collapsed into more dense shapes-a suspicion that is confirmed with TEM images. TEM results also indicated that primary particle size first decreases from low to medium load, then increases from medium to high load. An increase in EGR was also seen to increase primary particle size. Coefficients were determined for a relation that gives primary particle diameter as a function of projected area equivalent diameter. A decrease in load or speed results in a stronger correlation.

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Section: Introductionmentioning

confidence: 99%

Characterization of Particulate Matter Morphology and Volatility from a Compression-Ignition Natural-Gas Direct-Injection Engine

Graves

Olfert

Patychuk³

et al. 2015

Aerosol Science and Technology

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“…Previous work has suggested that oxygenated species can be attached to surfaces of soot particles of varying maturity emitted from flames and diesel engines, even before atmospheric processing (24)(25)(26)(27)(28)(29)(30)(31)(32). Functional groups that have been identified include alcohols/enols, carbonyls, peroxies, and ethers.…”

mentioning

confidence: 99%

Formation and emission of large furans and oxygenated hydrocarbons from flames

Johansson

Dillstrom

Monti

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. We used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that furans are produced in the high-temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ∼100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbonand oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming.furans | oxygenated hydrocarbons | soot | organic carbon | black carbon

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“…The mass loss at the air environment was taken as the mass of the non-volatile substances. Similar approach had been used by Boehman et al (2005) and Mustafi et al (2010) to distinguish the volatile and non-volatile fractions of diesel particles. The numberbased method was conducted by comparing the SMPS measurements with and without the Dekati thermo-denuder (TD).…”

Section: Experimental Methodsmentioning

confidence: 99%

“…However, for the LSD, the percentage of volatile particles exhibits monotonic increase with engine load. At low engine load, due to lower incylinder gas temperature, there is a larger amount of unburned hydrocarbon and lubricating oil in the exhaust gas which could be converted to volatile particles or condense on existing soot agglomerates (Ning et al, 2004;Ristovski et al, 2006;Mustafi et al, 2010), leading to an increase in particle volatility. The increase in volatility under high engine load is uncommon but has also been observed by Meyer and Ristovski (2007) through a VH-TDMA (volatilization and humidification tandem differential mobility analyzer) investigation on emissions from a six-cylinder diesel engine fueled with commercial 500-ppm-wt sulfur diesel fuel.…”

Section: Mass-based Investigation Of Particle Volatilitymentioning

confidence: 99%

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Influence of Waste Cooking Oil Biodiesel on the Particulate Emissions and Particle Volatility of a DI Diesel Engine

Tian

Cheung

Huang

2013

Aerosol Air Qual. Res.

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The effect of biodiesel produced from waste cooking oil on the particulate emissions of a direct injection (DI) diesel engine was investigated experimentally and the results were compared with two diesel fuels, namely, an ultra low sulfur diesel fuel with less than 10-ppm-wt of sulfur (ULSD) and a low sulfur diesel fuel with 400-ppm-wt of sulfur (LSD). For each fuel, the number and mass based particle emissions, as well as the particle volatility, were evaluated and compared. The particulate mass emissions were measured with a tapered element oscillating balance (TEOM) and further divided into different size bins using a micro-orifice uniform deposition impactor (MOUDI). The particle number concentration and size distribution were measured with a scanning mobility particle sizer (SMPS). The size-segregated samples collected with the MOUDI were further analyzed with a thermogravimetric analyzer (TGA) to obtain the mass of volatile substances in each size bin. The SMPS was further connected in series with a thermodenuder (TD) to obtain the number concentration and size distribution of non-volatile particles, and hence the number concentration and size distribution of the volatile particles. The results indicate that the biodiesel could effectively reduce the particle mass and number concentrations, including the volatile substances, in all the measured size range, compared with LSD. Compared with ULSD, there is also a reduction in the particle mass and number concentrations, however, a higher concentration of volatile substances was found with the use of biodiesel, which should be a concern in the application of this fuel.

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Characterization of Exhaust Particulates from a Dual Fuel Engine by TGA, XPS, and Raman Techniques

Cited by 46 publications

References 36 publications

Characterization of Particulate Matter Morphology and Volatility from a Compression-Ignition Natural-Gas Direct-Injection Engine

Characterization of Particulate Matter Morphology and Volatility from a Compression-Ignition Natural-Gas Direct-Injection Engine

Formation and emission of large furans and oxygenated hydrocarbons from flames

Influence of Waste Cooking Oil Biodiesel on the Particulate Emissions and Particle Volatility of a DI Diesel Engine

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