Flow pattern, circulation velocity and pressure loss in loop reactor.

A loop reactor is regarded as a new type of reactor for bulk polymerization of olefins. Several approaches to evaluate its performance are made herein. A simple model of discharge flow is proposed and related with the results obtained by measurement of average circulation velocity. The average circulation velocity is proportional to impeller speed and the sine of the impeller blade angle. It depends upon Reynolds number and dimensions of the impeller. Flow pattern was measured and the influence of baffles and impeller geometry is discussed qualitatively. In the case of unbaffled conditions, fluid flows in a helical motion. Intensity of this motion increases with impeller speed and pitched angle. In the case of baffled conditions, tangential velocity component is suppressed and normalized distribution of axial velocity is independent of impeller geometry. Pressure distribution was measured and pressure loss was obtained. Total pressure loss shows good agreement with the value calculated by superposition of frictional loss in straight parts and bend loss in bends obtained from established correlations.