Relevant Powder and Particle Properties

For non-porous solids, this is easily measured by a gas pycnometer or specific gravity bottle, but these devices should not be used for porous solids since they give the true or absolute density p bs the material of which the particle is made and this is not appropriate where interaction with fluid flow is concerned  

For porous particles, the particle density Pp (also called apparent or envelope density) is not easy to measure directly although several methods are given in Geldart (1990). Bed density is another term used in connection with fluidized beds bed density is defined as 

For example, 600 kg of powder is fluidized in a vessel of cross-sectional area 1 m and achieves a bed height of 0.5 m. What is the bed density  

If the particle density of these solids is 2700 kg/m, what is the bed voidage  

Bed density ps is related to particle density Pp and bed voidage s by Equation (7.12)  

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