MODELING OF ABS LATEX COAGULATION PROCESSES

The mathematical models of acrylonitrile-butadiene-styrene (ABS) latex coagulation processes that show the effect of major operation variabl es on the particle-size distribution of recovered resins were derived- to provide a guideline for process improvement to reduce the content o f fine particles in the product. Kinetic equations for the coagulation and breakup of particles taking place in a turbulent flow field were incorporated into the population balance models for batch and continuo us processes. A dimensional analysis for the process models leads to t wo dimensionless groups, eta(c) and eta(b) that represent the relative intensity of the coagulation and breakup phenomena. The eta(c)/eta(b) ratio is designated as a design variable for controlling the particle -size distribution in the steady-state operation of the coagulation pr ocesses. This role is demonstrated by numerical simulation where incre asing the ratio shifted the particle-size distribution toward large pa rticles. The estimates of eta(c)/eta(b) obtained for a set of batch ex periments also confirm that fine particles can be reduced by setting t he operation variables to increase the ratio.