Modelling of pulverized coal combustion with respect to fly ash particle size distribution

The present work aims to develop a simple model for describing the particle size distribution (PSD) of residual fly ash from pulverized biomass combustion. The residual ash formation was modelled considering the mechanism of fragmentation and coalescence. The influences of particle shape and stochastic fragmentation on model description of the PSD of the fly ash were investigated. The results showed that biomass particle shape has a great influence on the model prediction, and a larger fragmentation number is required for cylindrical particles than that for spherical particles to get the same PSD of fly ash, and the fragment number of the particles increases with the shape factor increasing. For pulverized biomass with a wide size distribution, the model predicted ash PSD considering the stochastic fragmentation is very similar to that assuming uniform fragmentation. It implies that the simple model assuming uniform fragmentation is applicable for predicting fly ash size distribution in practical processes where biomass particles have a wide range of sizes. For the fuel with a narrower initial PSD, the stochastic fragmentation model generally predicts a coarser PSD of the residual ash than assuming uniform fragmentation. It means the stochastic fragmentation is of great influence to be considered for accurate description of ash formation from the fuel with a narrow PSD.

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Factors Affecting the Density and Specific Surface Area (Blaine Value) of Fly Ash from Pulverized Coal Combustion

Energy & Fuels ◽

10.1021/ef201071e ◽

2011 ◽

Vol 25 (12) ◽

pp. 5700-5706 ◽

Cited By ~ 9

Author(s):

Hiromi Shirai ◽

Michitaka Ikeda ◽

Kenji Tanno

Keyword(s):

Fly Ash ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Coal Combustion ◽

Pulverized Coal ◽

Pulverized Coal Combustion ◽

Factors Affecting

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Influence of Particle Size Distribution of High Calcium Fly Ash on HVFA Mortar Properties

Civil Engineering Dimension ◽

10.9744/ced.20.2.51-56 ◽

2018 ◽

Vol 20 (2) ◽

pp. 51

Author(s):

Antoni . ◽

Hendra Surya Wibawa ◽

Djwantoro Hardjito

Keyword(s):

Particle Size ◽

Compressive Strength ◽

Fly Ash ◽

Particle Size Distribution ◽

Size Distribution ◽

Setting Time ◽

High Volume ◽

High Volume Fly Ash ◽

High Calcium ◽

High Calcium Fly Ash

This study evaluates the effect of particle size distribution (PSD) of high calcium fly ash on high volume fly ash (HVFA) mortar characteristics. Four PSD variations of high calcium fly ash used were: unclassified fly ash and fly ash passing sieve No. 200, No. 325 and No. 400, respectively. The fly ash replacement ratio of the cementitious material ranged between 50-70%. The results show that with smaller fly ash particles size and higher levels of fly ash replacement, the workability of the mixture was increased with longer setting time. There was an increase in mortar compressive strength with finer fly ash particle size, compared to those with unclassified ones, with the highest strength was found at those with fly ash passing mesh No. 325. The increase was found due to better compactability of the mixture. Higher fly ash replacement reduced the mortar’s compressive strength, however, the rate was reduced when finer fly ash particles was used.

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