SO2 oxidation method. Mathematical modeling taking into account dynamic properties of the catalyst

Mathematical modeling of a new sulfur dioxide oxidation method in sulfuric acid production has been carried out. The method is based on the use of the nonstationary state of the catalyst surface, in particular, the absorption properties of active component of vanadia catalysts in relation to SO,. Th e idea of the process is that the catalyst bed undergoes periodic cycling o f the feed between air flow and a reaction gas mixture, containing SO,. The directions of air and gas mixture flow are opposite. The unsteady-state ki netic model of SO, oxidation over vanadium catalyst is used to describe dyn amics of the catalyst state. The influence of different parameters on SO, c onversion and overall process performance is investigated. According to the modeling results, this method provides a decrease of the SO, outlet conten t in the waste gases down to 50 ppm and thereby avoids the need for tail ga s cleanup. The process may be easily applied to the second stage of a conve ntional DC/DA (double contact/double absorption) sulfuric acid plants. (C) 1999 Elsevier Science Ltd. All rights reserved.