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

Abstract

In the Japanese electric power industry, it is desirable to reduce the cost of treatment and expand the range of use of fly ash, such as in concrete admixtures. Therefore, it is necessary to form high-quality fly ash. To obtain high-quality fly ash, it is important to clarify the factors affecting its properties. In this study, the factors affecting the density and specific surface area (Blaine value) of coal fly ash were investigated on the basis of experimental results obtained using our combustion test facility and the ash data from the boiler of an actual electric power plant. The density was affected by the ash particle size, the true density of the component materials, and the aluminum content, which is closely related to the fusibility. The specific surface area was affected by the particle size distribution and particle shape. The shape was affected by not only the ash particle size but also the unburned carbon concentration and the ash fusibility. It was also found that the specific surface area of the ash generated from our combustion test facility is higher than that of ash from the actual boiler for ash with the same particle size. This result indicates that the shape of particles is affected by their heating and formation histories in the boiler. On the basis of the above findings, correlation equations were obtained for the density and Blaine value.

Numerical analysis on effect of furnace scale on heat transfer mechanism of coal particles in pulverized coal combustion field

“…Figure 9 shows the relationship between S Ab /S Ad value and the surface mean diameter, D s-ash for the 2.4 MW th test furnace and actual large scale boilers (different boilers from the 915 MW th boiler in this study) taken from the study conducted by Shirai et al [48]. S Ab is the specific surface area of the ash measured by the Blaine method [49] and S Ad is the specific surface area calculated from the ash particle size distribution and ash density on the assumption that ash particles are spherical.…”

Changes of Multiscale Surface Morphology and Pore Structure of Mudstone Associated with Supercritical CO2-Water Exposure at Different Times

“…Actually, compared with the PV, the SSA is also influenced by other factors (pore size distribution, pore shape, fractal dimension, etc. ), , which makes the changes of the SSA of different size pores more complex.…”

Utilization of Fly Ashes from the Coal Burning Processes to Produce Effective Low-Cost Sorbents

“…Type IV isotherms are given by many mesoporous industrial adsorbents and are generally associated with mesoporous materials (pore diameters between 1.7 and 50 nm). 42,43 It is well-known that the shape of the hysteresis loop reflects that of the pore structure. The hysteresis loops of samples FAI are similar to the hysteresis loop type H3, which is connected with the parallel-plate shaped pores (Figure 1).…”

“…Isotherms such as these can be classified as type IV (the hysteresis loop is associated with capillary condensation taking place in mesopores and the limiting uptake over a range of high p / p 0 ; however, its initial part is connected with the monolayer–multilayer adsorption) according to the IUPAC recommendations. Type IV isotherms are given by many mesoporous industrial adsorbents and are generally associated with mesoporous materials (pore diameters between 1.7 and 50 nm). , It is well-known that the shape of the hysteresis loop reflects that of the pore structure. The hysteresis loops of samples FAI are similar to the hysteresis loop type H3, which is connected with the parallel-plate shaped pores (Figure ).…”