The use of absorbents based on calcium for the reduction of SO2 emissions from power plants has been studied for the last 30years. The present work is part of a research project aimed at the development of a moving bed limestone filter. It is placed after burning in order to capture the SO2 from the flue gases of pulverized lignite combustors. A heterogeneous mathematical model was developed for the steady-state simulation of a gas-solid countercurrent moving bed reactor. The mathematical model was solved using the method of finite elements and gave results for the temperature and conversion profile along the reactor. Also, parametric analysis (for T-g,T-in, T-s,T-in, u(s), q(o), ySO2oO2o, d(o), z(o)) was performed and useful conclusions concerning the behavior of a moving bed reactor in different conditions were drawn. Finally, optimization of conditions was performed to give an SO2 conversion higher than 0.95. The results are of important technological interest as a dry process in applications of SO2 capture. (c) 2018 Society of Chemical Industry