Removal of sulfur trioxide by wet injection with alkaline absorbent: Model and experimental studies

Abstract

Sulfur trioxide (SO3) emissions from coal flue gas have become an increasingly serious issue, and alkaline absorbent injection technology has been successfully applied in industry as an effective control method. To accurately predict the SO3 removal effect, a new mathematical model based on the shrinking core model and mass conservation was proposed in this study. In this model, a fixed-bed adsorption experiment was used to estimate the absorption capacity of individual particles, and other model parameters were estimated. The theoretical results of the model were compared with the experimental results of an entrained flow reactor, the fitting parameters were determined, and the model was verified. In addition, the effects of key parameters such as the residence time, molar ratio, flue gas composition, and particle size of absorbers on the SO3 removal efficiency were compared and evaluated. Finally, the Sobol method was used to analyze the parameter sensitivity of the model. The results showed that particle size and porosity have an important influence on the removal of SO3, and thus should be considered when determining the type of absorbent.