BACKGROUND: Wet FGD technologies account for around 87% of such systems worldwide, particularly those that use limestone as the absorbent. This technique is widely used in large thermal power stations. Limestone reactivity is one of the parameters that most influence the yield of the FGD process. With the aim of improving the design and operation of desulfurization units, many studies have been carried out to investigate the rate of limestone dissolution. RESULTS: In this study, experimental equipment was set up to evaluate the limestone reactivity. In addition, a model to simulate the dissolution of limestone particles was developed. The proposed model considers the particle size distribution and composition, along with the pH of the liquid matrix where dissolution occurs. The average relative error between the experimental and numerically calculated results is 5%, after 10 min of experiment. CONCLUSION: A model based on film theory predicts with precision limestone dissolution as a function of the particle size distribution, chemical and physical composition of the limestone, pH and the solution composition. (C) 2010 Society of Chemical Industry