In this work we describe a numerical model of the evolution of the particle size distribution (PSD) during coal combustion. The model includes burning and fragmentation. The model examines the sensitivity of PSD evolution to different modes of fragmentation by allowing the input of alternative fragm
Combustion of millimeter sized coal particles in convective flow
β Scribed by Kenneth W. Ragland; Jing-Tang Yang
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- English
- Weight
- 673 KB
- Volume
- 60
- Category
- Article
- ISSN
- 0010-2180
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β¦ Synopsis
Continuous mass versus time data for single coal particles from 5.3 to 9.9 mm with gas temperatures of 900-1200K, Reynolds numbers of 63-126, and oxygen concentrations of 4.5-21% are presented. Devolatilization and char burn models for millimeter sized particles are formulated and compared with the experimental results. The devolatilization rate is most sensitive to particle size and gas temperature. The char reactivity depends on initial size, Reynolds number, and oxygen concentration. The devolatilization rate agrees with the model of Anthony and Howard when volatile yields are provided from experimental data. The char burning rate follows a diffusion controlled shrinking sphere model when a diffusion screening factor is included.
π SIMILAR VOLUMES
Data obtained by Campbell and Davidson on the particle size distribution (PSD) in a small fluid bed have been used to show that the equations for the PSD in a perfectly stirred reactor (PSR) can yield additional information on the PSD due to swelling and breakage of an entering stream that is nomina
An approach is made to predict fly ash production and characteristics on the basis of: experimental information from a power plant tracking programme; and the results of a pulverized coal combustion model. Conclusions presented in this paper do not agree completely with previous experimental results
A model of the ignition of a polydisperse cloud of brown coal particles, in a known gas environment, is presented and used to predict the behavior of the particles in a burner jet of a utility boiler. The model allows for drying, devolatilization, and char combustion of the particles. It is assumed