This work reports on a computer-simulated investigation of the coagulation rate for a system comprising spherical sol and coagulant particles. The discussed experiment positively verified the functioning of the simulated coagulation system, where the aggregation process proceeds in line with the particle-cluster model as a rapid and perikinetic coagulation process that satisfies the Smoluchowski equation. The rate of the simulated coagulation process satisfies kinetic equations for both first-order and second-order reactions. Selected concepts and models of the coagulation theory have been also verified. (c) 2012 Canadian Society for Chemical Engineering