Quantitative Flow-Reactor Study of Diesel Soot Oxidation Process

Yezerets, Aleksey; Currier, Neal W.; Eadler, Heather A.; Popuri, Sriram; Suresh, Arvind

doi:10.4271/2002-01-1684

Cited by 26 publications

(14 citation statements)

References 7 publications

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“…It can be observed from the Arrhenius plot in Figure 10 that the activation energy is independent of the conversion level, resulting in an average activation energy of 167 kJ/mol. This result is consistent with our previous studies and the literature, in which Ea in the range of 130-170 kJ/mol appears frequently for different soot sources [16][17][18]. In contrast, the kinetics parameters for Printex-U carbon black and engine soot using a step-response technique [17,24] and the same fitting procedure are tabulated in Table 3.…”

Section: Kinetic Analysis From Isothermal Studies (Nth Order Model)supporting

confidence: 91%

“…However, the reported activation energy for non-catalytic soot oxidation ranges from 92 to 211 kJ/mol since the employed experimental techniques and conditions vary from one group to another. Yezerets et al [16] compared the oxidative reactivity of diesel soot and carbon black, and the activation energies were found to be 92 and 117 kJ/mol, respectively. In another study of soot samples from different engine conditions [17], the activation energies for the soot with ash contents of 14 and 6.5% were found to be 126 and 146 kJ/mol, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Simulating Real World Soot-Catalyst Contact Conditions for Lab-Scale Catalytic Soot Oxidation Studies

Wang

Kumar

et al. 2018

Catalysts

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In diesel soot oxidation studies, both well-defined model soot and a reliable means to simulate realistic contact conditions with catalysts are crucial. This study is the first attempt in the field to establish a lab-scale continuous flame soot deposition method in simulating the “contact condition” of soot and a structured diesel particulate filter (DPF) catalyst. The properties of this flame soot were examined by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM) for structure analysis, Brunauer-Emmett-Teller (BET) for surface area analysis, and thermogravimetric analysis (TGA) for reactivity and kinetics analysis. For validation purposes, catalytic oxidation of Tiki® soot using the simulated contact condition was conducted to compare with the diesel particulates collected from a real diesel engine exhaust system. It was found that the flame soot is more uniform and controllable than similar samples of collected diesel particulates. The change in T50 due to the presence of the catalyst is very similar in both cases, implying that the flame deposit method is able to produce comparably realistic contact conditions to that resulting from the real exhaust system. Comparing against the expensive engine testing, this novel method allows researchers to quickly set up a procedure in the laboratory scale to reveal the catalytic soot oxidation properties in a comparable loose contact condition.

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Section: Kinetic Analysis From Isothermal Studies (Nth Order Model)supporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Simulating Real World Soot-Catalyst Contact Conditions for Lab-Scale Catalytic Soot Oxidation Studies

Wang

Kumar

et al. 2018

Catalysts

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“…The results from other researchers have varied widely in terms of kinetic values, such as activation energy and reaction order (Haralampous et al, 2004;Jung et al, 2004;Yezerets et al, 2002). This variation in kinetic values among studies can be attributed to different soot properties, as well as the inherent difficulties in sampling and measuring the reaction rate in a realistic way (Clague et al, 1999;Su et al, 2004;Vander Wal and Tomasek, 2003).…”

Section: Introductionmentioning

confidence: 91%

“…This sample dilution is usually intended to achieve better heat dissipation to limit the temperature rise by exothermic heat. Since there exists a flow direction temperature gradient in a flow reactor, the temperature non-uniformity inside the sample volume can increase with the addition of a diluent (Yezerets et al, 2002). Therefore no diluent was used in this study, which seems to simulate a DPF more realistically than the experiments with diluents.…”

Section: Experiments Setupmentioning

confidence: 98%

Measurement of soot oxidation with No2-O2-H2O in a flow reactor simulating diesel engine DPF

Jung

Lee

Chun

2008

Int.J Automot. Technol.

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Understanding the mechanism of carbon oxidation is important for the successful modeling of diesel particulate filter regeneration. Characteristics of soot oxidation were investigated with carbon black (Printex-U). A flow reactor system that could simulate the condition of a diesel particulate filter and diesel exhaust gas was designed. Kinetic constants were derived and the reaction mechanisms were proposed using the experimental results and a simple reaction scheme, which approximated the overall oxidation process in TPO as well as CTO. From the experiments, the apparent activation energy for carbon oxidation with NO 2 -O 2 -H 2 O was determined to be 40±2 kJ/mol, with the first order of carbon in the range of 10~90% oxidation and a temperature range of 250~500 o C. This value was exceedingly lower than the activation energy of NO 2 -O 2 oxidation, which was 60±3 kJ/mol. When NO 2 exists with O 2 and H 2 O, the reaction rate increases in proportion to NO 2 . It increases nonlinearly with O 2 or H 2 O concentration when the other two oxidants are fixed.

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“…18 The key feature of this technology is the development of DPM-free flame irrespective of the engine operating conditions, which involves compressed air as the source of oxygen for clean combustion in the burner. However, this method essentially results in an added fuel penalty and increases the complexity of the system in terms of the engine control unit, retrofitting, and sensor management.…”

Section: Introductionmentioning

confidence: 99%

Active Regeneration of Diesel Particulate Filter Employing Microwave Heating

Pallavkar

Kim

Rutman

et al. 2008

Ind. Eng. Chem. Res.

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Wall-flow diesel particulate filters (DPFs) are considered the most effective devices for the control of diesel particulate emissions. A requirement for the reliable operation of the DPFs, however, is the periodic and/or continuous regeneration of the filters. While microwave heating has been considered a potential active regeneration method for the DPFs, past studies on the technology have identified several technical problems leading to filter failure. The problems are mainly associated with the use of inappropriate filter materials for the microwave system and the generation of local hotspots due to uneven microwave heating, resulting in the physical damage to the filters. The objective of this study was to develop and demonstrate the technology employing a microwave-absorbing filter material coupled with an effective waveguide design for the reliable regeneration of DPFs. In this study, a well-equipped diesel emission control laboratory was established to conduct the experiments. The experimental facilities included a 6-kW e diesel generator, an exhaust flow control system, a diesel particulate filter system, a microwave energy supply system, a soot sampling system, a differential-pressure measurement system, and a temperature measurement system. The DPF was a silicone carbide wall-flow monolith filter enclosed in a quartz filter holder. A commercial 1.4-kW e microwave oven was modified to accommodate the quartz holder and a waveguide was engineered to evenly supply the microwave energy to the enclosed filter to achieve filter regeneration. In the experiments, the diesel engine exhaust was lined up to flow through the filter with a fixed flow rate. The microwave regeneration was triggered after a specific amount of soot loading was reached based on the differential pressure drop reading. The results have indicated that the designed system has been able to achieve uniform temperature profiles both in the radial and the vertical DPF positions. The off-line regeneration of DPF by microwave energy has been observed to be highly efficient in terms of energy consumption and regeneration efficiency. The DPM filtration efficiency has remained comparably high after 150 cycles of filtration/regeneration with no apparent physical damage to the DPF being observed. The on-line microwave regeneration of the DPF, however, is not as efficient as the off-line regeneration due to the insufficient oxygen concentration in the engine exhaust stream.

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Quantitative Flow-Reactor Study of Diesel Soot Oxidation Process

Cited by 26 publications

References 7 publications

Simulating Real World Soot-Catalyst Contact Conditions for Lab-Scale Catalytic Soot Oxidation Studies

Simulating Real World Soot-Catalyst Contact Conditions for Lab-Scale Catalytic Soot Oxidation Studies

Measurement of soot oxidation with No2-O2-H2O in a flow reactor simulating diesel engine DPF

Active Regeneration of Diesel Particulate Filter Employing Microwave Heating

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