Apparent particle density

Biofilm Effects. Particle size and density are especially important in determining the success of biofluidization. Bioparticle size and density are determined by the initial particle properties, the extent of biomass growth, and biofilm density. For a biofilm covered support, the apparent particle density is determined by Eq. (7) (Fan, 1989). 

Apparent particle density Mass of particles divided by its apparent particle volume, which is defined as the total volume of the particle, excluding open pores but including closed pores (BSI) ... 

A comparison of true particle density, apparent particle density, and bulk density can provide information on total porosity, interparticle porosity, and intraparticle porosity. Methods include true particle density measurements via helium pycnometry, mercury intrusion porosimetry, and poured and tapped bulk density. 

The apparent particle density, pp, is the ratio of the particle weight to the particle volume, or sum of the imaccessible volumes and the internal pore volume. This is the most practical definition. However, it carmot be as accurate as densities usually are because of the difficulty associated with defining accurately the external column porosity (see previous subsection),... 

APPARENT PARTICLE DENSITY is when the volume measured includes closed pores or bubbles of gas within the particle. This density is measured by gas or liquid displacement methods like the liquid or air pyknometers (see below). 

The apparent particle density (or if the particles have no closed pores, also the true particle density) can be measured by fluid displacement methods, i.e. pyknometry, which are in common use in industry today. The displacement can be measured with either liquids or gases and there are, therefore, two groups of techniques and instruments available, as follows. 

The method will measure the true particle density if the particles have no closed pores or the apparent particle density if there are any closed pores, because the volume measured normally excludes... 

Apparent particle density is when the volume measured includes intraparticulate pores. 

The above minimum binder content values specified are to be corrected when the apparent particle density of the aggregate deviates from 2650 Mg/m by multiplying them by the factor (a), which is determined by the following equation ... 

Any of the three particle densities defined above should not be confused with bulk density of materials, which includes the voids between the particles in the volume measured. The different values of particle density can be also expressed in a dimensionless form, as relative density, or specific gravity, which is simply the ratio of the density of the particle to the density of water. It is easy to determine the mass of particles accurately but difficult to evaluate their volume because they have irregular shapes and voids between them. The apparent particle density, or if the particles have no closed pores also the true density, can be measured by fluid displacement methods, that is, pycnometry, which are in common use in industry. The displacement can be carried out using either a liquid or a gas, with the gas employed normally being air. Thus, the two known techniques to determine true or apparent density, when applicable, are liquid pycnometry and air pycnometry. 

Test no. Feed flow rate (kgh ) Foaming gas flow rate (gh ) Sauter mean diameter (fim Bulk density (kg ) Tap density (kg ) Apparent particle density (kgm ) Angle of repose ( ) Particle porosity (%) Solubility (%) Wetting time (s)... 

The apparent particle density is an important parameter for the design of fluidized bed columns. For example, the amount of solids elutriated from a fluidized bed column depends greatly on the apparent particle density of the bed solids. It is quite difficult to measure the apparent particle density of porous particles and the experimental value of the minimum fluidization velocity can be used for its evaluation [28]. 

The average bed voidage can be estimated from the measured bed height. If both the apparent particle density and the total mass of solids present in the bed are known, the bed voidage can be obtained with ... 

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