This paper considers two ways of improving the annual production capacity of an industrial suspension process for the polymerization of vinyl chloride. Currently, this plant has a production of about 300 ton/(m(3) year) per reactor. To achieve higher production, two techniques Were applied: increasing the final temperature of the reaction and injecting additional reactant partway through the reaction. Experiments were carried out to analyze the effects of each technique separately on the quality of the resin and productivity of the process, and statistical tools were applied to optimize the responses of a combined process. Compared to previous quality specifications (apparent density, porosity, K-value and average particle diameter), there were no significant differences in the quality of the final product. Applying both techniques simultaneously increased the productivity by 19.1%, with no additional investment required by the plant. (C) 2008 Elsevier B.V. All rights reserved.