H2o2 Addition to Diesel Engine Exhaust Gas and Its Effect on Particles

Franz, B.; Eckhardt, T.; Kauffeldt, Th.; Roth, P.

doi:10.1016/s0021-8502(99)00537-6

Cited by 13 publications

(6 citation statements)

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“…This is what we observed at lower furnace temperatures, but at temperatures above 500 °C, the signal begins to diminish significantly because of the apparent disappearance of the positive charge on the particles, so by 800 °C, the signal is 10% of that at 500 °C, and at 900 °C, there are no detectable particles. This same phenomenon was apparently observed in a previously published study of the effect of H 2 O 2 on diesel soot 18 but was left without comment. The 3760 CPC requires on input flow rate of 1.415 L min -1 , so a small amount of make-up air is sampled through a filter from the room air to supplement the 1.0 L min -1 aerosol output of DMA-2.…”

Section: Methodssupporting

confidence: 78%

“…McMurry et al studied the reaction between ammonia gas and sulfuric acid aerosols by measuring the hygroscopic and deliquescent properties of the product aerosols . Recently, Franz et al used a TDMA apparatus in conjunction with a thermolysis tube to study the effect on diesel soot particles of H 2 O 2 addition to the exhaust stream . Their measurements were concerned with the evaporation of the volatile fraction of the particles and were only performed up to a thermolysis temperature of 650 °C.…”

Section: Introductionmentioning

confidence: 99%

“…17 Recently, Franz et al used a TDMA apparatus in conjunction with a thermolysis tube to study the effect on diesel soot particles of H 2 O 2 addition to the exhaust stream. 18 Their measurements were concerned with the evaporation of the volatile fraction of the particles and were only performed up to a thermolysis temperature of 650 °C.…”

Section: Introductionmentioning

confidence: 99%

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Size-Selected Nanoparticle Chemistry: Kinetics of Soot Oxidation

et al. 2001

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A new experimental method has been developed to conduct surface chemistry and extract surface kinetic rates on size-selected nanoparticles. The method utilizes a tandem differential mobility analyzer (TDMA) technique in which monodisperse particles are selected from a polydisperse aerosol input stream and then subjected to chemical processing. The change in particle size is measured and used to determine kinetic information for the relevant surface reaction. The method has been applied to measure the oxidation rate of soot in air over the temperature range 800-1120°C. Soot was generated in situ using an ethylene diffusion flame and sent to a differential mobility analyzer (DMA) to extract monodisperse particles. Three initial particle sizes of 40, 93, and 130 nm mobility diameter were subjected to oxidation in a high-temperature flow reactor, and the resulting change in particle size was measured with a second DMA. The measured size decreases were fit to a model utilizing a modified Arrhenius expression for the rate of decrease: Ḋ p ) -A nm T 1/2 exp(-E a /(RT)). The fit yielded an activation energy of E a ) 164 kJ mol -1 with a different preexponential factor, A nm , for each initial particle size. The size-decrease rates, and therefore the preexponential factors, differed by a factor of 1.7 between the 40 and 130 nm particles, with the 130 nm particles decreasing faster than the 40 or 93 nm particles. This may be the result of several factors including different effective densities or different soot particle compositions. The current experiments are the first measurements of the soot oxidation rate to be performed on size-selected, freshly generated soot particles using online aerosol techniques. Our results agree well with previous work over the temperature range covered, which is somewhat surprising given the wide range of techniques and materials previously studied in the effort to understand soot oxidation.

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Section: Methodssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

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Size-Selected Nanoparticle Chemistry: Kinetics of Soot Oxidation

et al. 2001

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“…Often, diesel soot emissions, and emission reduction systems, are examined with particle-sizers such as the scanning mobility particle sizer (SMPS; Wang & Flagan, 1990) and the electrical low-pressure impactor (ELPI; Keskinen, Pietarinen, & Lehtm aki, 1992; Marjam aki, Keskinen, Chen, & Pui, 2000a). Examples from literature on ÿlter-and catalyst technology tested with the SMPS include Hawker et al (1997), Mayer et al (1999), Abdul-Khalek, Kittelson, and Brear (1998), Franz, Eckhardt, Kau elt, and Roth (2000), Lepperhof, Stommel, L uers, and Searles (2000), Graskow, Ahmadi, Morris, and Kittelson (2000). Clearly many authors trust the SMPS.…”

Section: Introductionmentioning

confidence: 99%

Measuring diesel soot with a scanning mobility particle sizer and an electrical low-pressure impactor: performance assessment with a model for fractal-like agglomerates

Gulijk

Marijnissen

Makkee

et al. 2004

Journal of Aerosol Science

132

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“…Bilde and Pandis (2001) measured evaporation rates and vapor pressures of individual organic aerosol species with varying residence times and temperature in the laminar flow tube. McMurry et al (1983) measured the reaction rates between ammonia gas and sulfuric acid aerosols by measuring hygroscopic and deliquescent properties of the product aerosols, while Franz et al (2000) looked at effects of addition of H 2 O 2 on diesel soot particles using a thermolysis tube and TDMA. Khalizov et al (2006) developed and characterized a laminar aerosol flow reactor to study ice nucleation, deliquescence and efflorescence in model atmospheric aerosols in the temperature ranges of 240-300 K. Higgins et al (2002) measured soot oxidation rate using the reactor and TDMA at temperatures ranging 500-1100…”

Section: Introductionmentioning

confidence: 99%

Modeling Oxidation of Soot Particles Within a Laminar Aerosol Flow Reactor Using Computational Fluid Dynamics

Shrivastava

Gidwani

Jung

2009

Aerosol Science and Technology

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This work examines the measurement of surface specific soot oxidation rates with the High Temperature Oxidation-Tandem Differential Mobility Analyzer (HTO-TDMA) method. The Computational Fluid Dynamics package CFD-ACE + is used to understand particle flow, oxidation and size dependent particle losses in the laminar aerosol flow reactor using an Eulerian-Lagrangian framework. Decrease of DMA selected mono-disperse particle size distribution due to oxidation within the aerosol tube is modeled using fitted kinetic soot oxidation parameters. The effects of Brownian diffusion and thermophoresis on particle flow and loss to the reactor walls are evaluated. The position of peak particle diameter, which is used as an indicator to determine oxidation rate, is found to be independent of diffusion, thermophoresis and secondary flow effects, thus validating its use in deriving kinetic soot oxidation parameters. Diffusion does not affect the evolution of particle size distribution within the reactor. However, thermophoresis is found to be the dominant mechanism influencing both shape of particle size distribution and particle loss to the walls of the aerosol reactor. Simulations show reduced effects of secondary recirculating flows on the particle flow trajectories in a vertical furnace as compared to horizontal furnace orientation. This work highlights the importance of making accurate measurements of temperature within the modeling domain. Since gas temperature within the flow tube could not be measured with high radial resolution using radiation shielded thermocouple, the derived soot oxidation rate may be uncertain by a factor of 2. Importantly, CFD simulations suggest that a distribution of size-dependent particle reactivities may be present in the reactor temperature and requiring further theoretical and experimental investigation.

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H2o2 Addition to Diesel Engine Exhaust Gas and Its Effect on Particles

Cited by 13 publications

References 0 publications

Size-Selected Nanoparticle Chemistry: Kinetics of Soot Oxidation

Size-Selected Nanoparticle Chemistry: Kinetics of Soot Oxidation

Measuring diesel soot with a scanning mobility particle sizer and an electrical low-pressure impactor: performance assessment with a model for fractal-like agglomerates

Modeling Oxidation of Soot Particles Within a Laminar Aerosol Flow Reactor Using Computational Fluid Dynamics

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