![]() When the moisture and volatiles are driven off from the particle, the resulting char has lower density with respect to the original fuel, sometimes a much lower density (as for biomass and waste). It is important to underline that the particle density significantly changes upon drying and devolatilization. In fact, low density fuels (biomass and waste) are more likely to float on the surface of the dense bed, while higher density fuels (coals) are more uniformly mixed along the bed height. It also has important implications in the mixing/segregation behaviour of the fuel in the fluidized bed. Particle density affects fuel handling and storage as well as transportation. Montagnaro, in Fluidized Bed Technologies for Near-Zero Emission Combustion and Gasification, 2013 7.2.4 Density In addition, smaller particle diameter leads to higher average solids velocities at the two planes investigated, and the slip velocity between the solids and gas increases with increasing particle diameter.į. It seemed that a high-velocity zone is corresponding to a low solids volume fraction zone. The effect of particle diameters on solids velocity contours is not obvious from Figs. 23.8 and 23.9. For 30 and 50 micron particles, bend effect is minimized at plane 1, but for 10 micron particles, bend effect still exists, and the solids are filled in all the space. More solids are concentrated on the bottom of the pipe for larger diameters, most likely because of increased gravitational effect, which is more obvious after the bend. The solids are distributed more evenly with the smaller particle diameter. The two planes are before and after the bend respectively as shown in Fig. 23.4. The effect of particle diameter on solids volume fraction and velocity at the plane 1 and plane 2, were illustrated in Figs. 23.8 and 23.9. Compaction allows these void spaces to be filled with solids. The bulk density for fine soils is more sensitive to compaction because of large void spaces in the loose condition. Figure 7.11 shows a general relationship between bulk density and compaction for both coarse- and fine-textured soils. ![]() The bulk densities of clay, clay loam, and silt loam surface soils normally range from 1.00 to about 1.60 g/cm 3, whereas sandy loams may have bulk densities ranging from 1.20 to 1.80 g/cm 3 ( Brady, 1974). Soil particles in a fine-textured soil typically do not lie closely together, but instead tend to bridge between individual particles so that large pores may exist. Sandy soils, particularly those with low organic matter, generally fit tightly together. Brady (1974) discussed the factors affecting bulk density, indicating that loose and porous materials have lower bulk densities than more compact materials. Bulk density is defined as the mass of a unit volume of dry sediment, including both solids and pores. ![]() CBA has a particle density of about 2.3 and this is higher than the values obtained for POC and OPS and would make the mortar or concrete with a higher density compared to other mixes.īulk density provides a second way of defining sediment weight. However, the particle density of the LWA obtained from the industrial wastes, namely POC and OPS had the relative density in the range of 1.20–1.87. The relative density of LWA, such as sintered FA, expanded clay, foamed slag, and so forth varied in the range of 1.41–2.66. For some aggregates, the particle density is higher for the smaller particles than for the larger ones, because the larger particles are more expanded. The particle density depends mainly on the void content of the particles. The particle density is a function of both the specific density of the material and of the void content of the particles. This volume includes the voids within the particles but does not include the space between the particles. The particle density of an aggregate is the ratio between the mass of a certain quantity of the aggregate and the volume of all individual particles of the quantity. ![]() Johnson Alengaram, in Handbook of Sustainable Concrete and Industrial Waste Management, 2022 2.16.2 Particle density
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