Application of acoustic agglomeration for fine particle emission control

Author: Shaw, D. T.
Published: United States : [publisher not identified], 1978.
Springfield, Va. : National Technical Information Service, [approximately 1978]
Physical Description: microfiche : negative ; 11 x 15 cm
Additional Creators: Cheng, M. T., Patel, S., and Wegrzyn, J.

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Summary

Flue gases are routinely purged of their suspended fly ash burden by passing through (1) an electrostatic precipitator, (2) a scrubber, or (3) a fabric filter. These devices remove the coarser particles more efficiently than they do the finer. If the dusty gas were first pretreated by passing it through a sonic agglomerator, so that nearly all the finer particles were agglomerated into coarser ones before entering any of the above collector types, the overall collection efficiency would be improved. This report investigates the economic feasibility of such an approach. The investigation has been of a theoretical nature, supplemented by experiments on a laboratory scale, in order to evaluate sonic agglomeration constants with polystyrene latex particles, dioctyl phthalate particles, Fe/sub 2/O/sub 3/ particles, and others. The investigation indicates that intense acoustic fields cause the finer suspended particles to collide with the coarser ones in a process called orthokinetic interaction. To maintain the essential supply of coarse particles, the use of a spray to inject droplets into the sonic field appears to be helpful. The results clearly indicate that the sonic agglomerator, when viewed as a prospective auxiliary to present day electrostatic precipitators, is not an economically attractive option due to the high power requirements. In a typical modern pulverized-coal-firing utility station with a gas flow rate of 1 million ft/sup 3//min, the agglomerator would require about 1000 hp. This is certainly more power than used by current fabric-filter technology, which meets all proposed emission and opacity standards. Moreover, with the required intense sound levels of 150 decibels, sound muffling problems become serious. Assuming that a sonic agglomerator in tandem with an electrostatic precipitator would meet emissions standards at a power station, there would be sound-level code violations unless elaborate and expensive sound-deadening measures were used.

Report Numbers

EPRI-FP-887

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NTIS collection.

Note

OSTI Identifier 6562500
Research organization: State Univ. of New York, Buffalo (USA).

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