Measurement and Prediction of Ash Deposition Rates for Air- and Oxy-Combustion of a Wide Range of Solid Fuels

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Title Measurement and Prediction of Ash Deposition Rates for Air- and Oxy-Combustion of a Wide Range of Solid Fuels
Creator Wang, Y.
Contributor Wendt, J.O.L.
Date 2018-09-18
Description Paper from the AFRC 2018 conference titled Measurement and Prediction of Ash Deposition Rates for Air- and Oxy-Combustion of a Wide Range of Solid Fuels
Abstract This paper presents a synthesis of a large body of experimental data describing rates of ash deposition from solid fuel combustion from nine fuels burned under a range of air- and oxy-combustion conditions (or 30 conditions in all). The experimental data were obtained from a 100kW (rated) down-flow combustor that allowed self-sustained pulverized solid fuel combustion. These conditions simulated practical conditions as far as temperature- time histories, and gas and particle concentrations are concerned, although the flow was necessarily laminar at the deposit probe location. Deposition rates were measured using a wall temperature controlled deposition probe, and the collected deposits can be divided into the tightly bound "inside deposit", closest to the heat transfer surface, and the loosely bound "outside deposit" that is more easily removed by soot blowing. The size segregated ash aerosol data were obtained using Electric Mobility and Light Scattering methods and Low Pressure Impactors. The focus of this paper is on exploring the ash transformation in different fuels and developing universal relationships between ash aerosol characteristics and the deposition rates. The results from all the fuels (fossil and biomass), under both air and oxy-combustion conditions suggest the formation of the inside deposit layer and the outside deposit layer involve different mechanisms, and their deposition rates have different dependencies. Specifically, the deposition rate of the "inside deposit" layer is proportional to the concentration of sub-micron particles (PM1), of any composition, in the flue gas. In contrast to inside deposits, the deposition rate of the "outside deposit" layer is roughly proportional to the total alkali concentration in the flue gas, but not to PM1 concentration. The formation of submicron particles is found to be significantly boosted under high temperature advanced oxy-combustion cases. The practical consequence of these findings is that, in general, increasing ash concentrations and flame temperatures (as in advanced oxy-combustion) will lead to higher deposition rates.
Type Event
Format application/pdf
Rights No copyright issues exist
OCR Text Show
Metadata Cataloger Catrina Wilson
ARK ark:/87278/s6xm2rj4
Setname uu_afrc
Date Created 2018-12-12
Date Modified 2018-12-12
ID 1389184
Reference URL https://collections.lib.utah.edu/ark:/87278/s6xm2rj4
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