PRELIMINARY DESIGN OF A LOOP REACTOR FOR BULK PROPYLENE POLYMERIZATION

Some typical problems in the early design stages of a tubular loop reactor for bulk propylene polymerization are analyzed. Characteristic variables are identified, and a shortcut method for the preliminary estimation of the reactor dimensions is developed. The influences of process variables such as catalytic activity, suspended solid fraction, and average particle size are studied. In particular, a relationship between the average particle size in the reactor and the particle size at both the inlet and the outlet is obtained. The behavior of the reactor under different operating conditions is studied, and critical parameters are identified. Most relevant results are related to the importance of the particle size inside the reactor. The two goals of maximum yield and maximum productivity for a given loop reactor configuration cannot be achieved simultaneously: While catalyst yield increases with the third power of the average particle size in the reactor, the smaller the average particle size in the reactor, the greater the productivity. The steps to be followed for a preliminary design of a propylene polymerization, loop reactor are discussed. A priority list for the sequence of parameters to be adopted is proposed, according to the relative importance of the variables involved. © 1990, Taylor & Francis Group, LLC. All rights reserved.