An increase in acid gas (H2S and CO2) production from crude oil and gas and the demand of high efficiency in sulfur recovery units (SRUs) to minimize sulfur emissions have triggered significant interest in optimization studies. A model for multi-objective optimization of SRU is developed, where a detailed reaction mechanism for sulfur production and destruction of undesired aromatics, CO, COS, and CS2 is utilized. The model is validated using an SRU plant data. The thermal and the catalytic sections of the SRU are simulated in Chemkin Pro and Aspen Hysys, respectively. Matlab is used for their integration and optimization using genetic algorithm and artificial neural network. The optimum conditions for SRU operation are reported, where the fuel gas consumption reduced by 98%, the required temperatures of the air and the acid gas decreased by 142 and 4 degrees C, respectively, and a low aromatics emission (<1 ppm) could be maintained. (C) 2019 Elsevier Ltd. All rights reserved.