Scale-up of suspension polymerization reactors

The scale-up of suspension polymerization reactors (i.e., from lab to pilot and then to industrial scale) is not straightforward or well established. Probably, the most significant problem in scale-up occurs when different physical processes become Umiting at different scales. For example, commercial-scale suspension reactors have to perform several functions simultaneously (dispersion, reaction and heat transfer), which do not scale-up in the same manner. Thus, heat removal can become a Umiting factor for reactor performance at large scales while it is rarely a problem for lab-scale reactors [86]. 

Equation 5.24 assumes that the power number remains constant. The power number represents the ratio of pressure to inertia forces [88]. Thus, this criterion represents dynamic similarity under conditions of negligible viscous forces (i.e., large Reynolds numbers), and no effect of gravitational forces (e.g., the presence of baffles). 

The criterion of equal tip speed, under constant geometry, leads to the following relation  

Okufi et al. [88] studied the scale-up effect on the DSD of n-heptane in water, and reported that the rule of equal impeller tip speed provided the best scale-up criterion for equal interfacial areas per unit volume of dispersion, while the criterion of equal input power per unit volume resulted in the production of smaller droplets. Scully [89] used the well-known correlation between the Sauter mean diameter 

He proposed that in order to keep the Sauter mean diameter of the polymer particles constant in reactor scale-up, the following condition should be satisfied  

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