Homogeneous oxidation of SO2 in the tail gas incinerator of sulfur recovery unit

Abstract The formation and emission of sulfur trioxide (SO 3 ) in sulfur recovery unit has received increasing attention due to its adverse effects on the operation of plant and environment. Due to the excess oxygen, high concentration of SO 2 and high temperature, SO 3 formation in the sulfur recovery unit tail gas incinerator may significantly increase. A small horizontal tube reactor was employed to simulate the homogeneous oxidation of SO 2 in the tail gas incinerator. The SO 3 concentration was measured with a controlled condensation method at the outlet of the reactor. The present work focuses on the gas-phase chemistry and examines the impact of different combustion parameters and atmospheres on the formation of SO 3 in the tail gas incinerator. Experiment results show that the increased O 2 and SO 2 concentrations along with increasing temperature are favorable for enhancing SO 3 formation over the range of tested parameters. The presence of water vapor has an enhancing effect of SO 2 oxidation in the experiments conducted. No significant effect of CO 2 was found to the oxidation of SO 2 .