Representing Granulation Processes Through Population Balances

REPRESENTING GRANULATION PROCESSES THROUGH POPULATION BALANCES 

The particulate nature of solids is characterized by a number of properties, such as size, shape, liquid and gas content, porosity, composition, and age. These are denoted as internal coordinates, whereas Euclidian coordinates, such as rectangular coordinates (x, y, z), cylindrical coordinates (r, 4 , z), and spherical coordinates (r, 6, 4 ) used to specify the locations of particles, are defined as external coordinates. 

The most important property for the characterization of particles is particle size. Randolph and Larson (36) pointed out that As no two particles will be exactly the same size, the material must be characterized by the distribution of sizes or particle-size distribution (PSD). If only size is of interest, a single-variable distribution function is sufficient to characterize the particulate system. If additional properties are also important, multivariable distribution functions must be developed. These distribution functions can be predicted through numerical simulations using population balance equations (PBE). 

Ramkrishna (35) provided a brief explanation on the population balance equation The population balance equation is an equation in the foregoing number density and may be regarded as representing a number balance on particles of a particular state. The equation is often coupled with conservation equation for entities in the particles environmental (or continuous) phase.  

In this chapter, both single-variable and multivariable population balances are described. However, emphasis will be placed on the single-variable population balance equations with size as the only internal coordinate. 

---

REPRESENTING GRANULATION PROCESSES THROUGH POPULATION BALANCES... 

---