Ultrasonic Disintigration of Particles

Dooher, J.; Lippman, R.; Morrone, Terry; Pohle, Hugh; Wright, David C.

doi:10.1109/ultsym.1977.196783

Cited by 5 publications

(9 citation statements)

References 6 publications

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“…As the curves show, the smoke point in all cases is at about 10% excess air, and is not evidently affected by t"'e emulsification. This seems to be contrary to all previous results (see Reviews,[1][2][3]. As the curves also show, however, emulsification does clearly reduce the smoke level, at the same excess air level, for excess air less than that at the smoke point.…”

Section: Scope Of Experiments and Experimentalcontrasting

confidence: 99%

“…such as nitrogen and carbon dioxide surface areas, mercury and helium "densities, porosities, etc., also vary significantly with -r. , (3) weight .…”

Section: Lsomentioning

confidence: 99%

“…Included as advantages (some inter-related) one can find: increased power from engines, decreased engine cooling requirements, elimination of hard kqock, increased thermal efficiency, increased combustion efficiency, reduced excess-air requirements, reduced flame length, faster burning, improved atomization,, reduced NOx emissions, reduced so 3 production from so 2 , ~ower combustion noise, less carbon build up, and reduced smoke or combustible particulate emissions. Huch of this is covered in three recent reviews (1)(2)(3). To the extent that the claims are substantiated, water addition is clearly advantageous, although supporting data are still not fully in evidence.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of American coals in relation to their conversion into clean energy fuels. Quarterly technical progress report, January--March 1976. [2 appendices; 19 refs. Dryflo separation tests data]

Spackman¹,

Walker²,

Lovell³

et al. 1976

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Responses to the questionnaire, which was distributed to determine. the exfent to which the nation's coal seams have been sampled and characterized, are being received. Early comparisons indicate a mathematical relationship between avera.ge random n! rl ectance (Rapid Scan) and thP. mean-maximum reflectance as obtained by standard reflectance analysis. Results obtained so far show support of a diffusion dominance• mechanism in the oxidation region of a combustion pot•and a chemical kinetic mechanism in the gasification region. Values of reaction rates in coke beds have been calculated from experim~nts with a fixed bed shaft gasifier. • Devolatilization of a North Dakota lignite in a laminar flow reactor dnd subsequent treatment of thP. resultinq char has shown that weight loss is strongly dependent upon the isothermal decomposit.ion time. Although gasification rates increase with increase in partial pressure of oxygen, the mechanism for gasification of a given char is jndependent of partial pressure of oxygen. Study of the reactivity of ion-exchanged lignite chars to steam shows that increased heat treatment decreases reactivity and ion exchange increases reactivity. Use of the DSC technique to study the thermal effects involved. during chemisorption of oxygen on Saran carbon has yielded information on the activation energy (Ea) of the reaction. Work on the infinite'parallel plane char combustion comput~r model has determined that low volatile chars and coals can be suitable fuels if adequate available internal. surface area is present. • iii TABLE OF CONTENTS

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Section: Scope Of Experiments and Experimentalcontrasting

confidence: 99%

“…such as nitrogen and carbon dioxide surface areas, mercury and helium "densities, porosities, etc., also vary significantly with -r. , (3) weight .…”

Section: Lsomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characteristics of American coals in relation to their conversion into clean energy fuels. Quarterly technical progress report, January--March 1976. [2 appendices; 19 refs. Dryflo separation tests data]

Spackman¹,

Walker²,

Lovell³

et al. 1976

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“…Thus, it was observed that these coals could be equivalently dispersed by either the ultrasonic or mechanical mixer. Although attrition of relatively large coal particles (250 micron) by ultrasonic energy has been reported in the literature (Dooher et al, 1977), these results above cannot conclusively support or reject the conclusion that an ultrasonic dispersator can disintegrate both primary particles as well as aggregates of primary particles.…”

Section: Mechanically Mixed Coavparaff In Oil Suspensionsmentioning

confidence: 66%

“…The Hardgrove Grindability Indices of the lignite and the Illinois are above 50 and 60, respectively, while the values reported for coal samples obtained from the Sewell and Pocahontas Seams are between 100 and 110 (McNally, 1976). Although Dooher et al (1977) has shown that severe ultrasonic treatment may disintegrate primary coal particles in No. 2 oil to an extent which increases as the Hardgrove Grindability of the coal decreases, the gentle ultrasonic treatment applied here has been shown not to significantly effect the primary particle size distribution af the coal (Filmyer, 1981).…”

Section: Ultrasonically Mixed Coal/paraffin Oil Suspensionsmentioning

confidence: 99%

The sedimentation of coal in model oils: The effect of the viscosity and composition of the oil

Adams-Viola

Botsaris

1982

AIChE Journal

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The results of batch settling tests with various coal powders in model oils indicated that the viscosity and the aromatic/paraffinic nature of the oil influences G. 0. BOTSARlS and YULl GLAZMAN the sedimentation and the aggregation rate of the particles. Oxidation of paraffin oil may result in the generation of surface active agents which retards the sedimentation of certain coals. Department of Chemical EngineeringTufts University Medford, MA 02155 SCOPEA coal-oil mixture (C0M)-a dispersion of finely pulverized coal in No. 6 fuel oil-is an alternative fuel to be used as an interim measure to reduce oil imports without requiring major renovations to existing oil-fired power facilities. A question which has been raised is how significant the variability of the chemical and physical properties of the residual oil is to the sedimentation behavior of the coal-oil slurry. This variability includes differences in the content of aromatic compounds, in the content of asphaltenes and in the content of naturally occurring or deliberately added surface active agents (Dodd et al., 1952). Ekmann and Bienstock (1979) have compared the sedimentation of Pittsburgh Seam coal in several different No. 6 oils. A regression analysis was performed with the settling data and various oil characteristics. The results indicated to a level of 99% confidence that the oxygen/nitrogen ratio of the asphaltenes, the nitrogen/carbon ratio of the asphaltenes and the kinematic viscosity are correlated to the sedimentaton kinetics of the slurry. The complexity of No. 6 oil required a statistical approach to the interpretation of the data. With this in mind and with the appreciation that even the meaningful characterization of No. 6 oil is in itself a current problem, an experimental scheme was developed in this work using model oils such as hexane, toluene, kerosene and paraffin oil and their mixtures rather than No. 6 oil itself. The use of these model oils, unlike the black and opaque No. 6 oil, also permitted the rapid evaluation of the sedimentation kinetics.The COM prepared with model oil were employed to study the effect of the viscosity and the paraffinic/aromatic composition of the oil on the settling behavior of the coal. The effect of viscosity was studied by comparing the settling rates of suspensions of four different coals having closely matched particle size distributions (including a lignite and three bituminous coals) in hexane and kerosene at 22°C and in paraffin oil at 45OC and 70°C. The slurries in paraffin oil were prepared using both a mechanical dispersator and an ultrasonic dispersator. The effect of the chemical composition (paraffinic/aromatic nature) of the oil was investigated by comparing the settling velocities of six coals having closely matched particle size distributions (including an anthracite, four bituminous samples and a lignite) in toluene, in hexane and in the three toluene/hexane mixtures at room temperature. CONCLUSIONS AND SIGNIFICANCEThe experimental data indicated that variations of the oil viscosity...

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