An oxidative kinetic model of total sulfite in ammonia-based wet flue gas desulphurization process

Previous studies regarding oxidation of total sulfite in ammonia-based desulphurization process has not taken the effects of bisulfite and ionic strength,etc. into account. Experimental apparatus were set up to study the effects of SO2-3concentration,SO2-4concentration,pH,temperature and amount of air on the oxidative kinetics of total sulfite. The experimental results show that the oxidation rate of total sulfite is-0. 5 order with respect to sulfite,and its relationship with SO2-4concentration is,r( IV)= 0. 00121exp(- 0. 89CSO2-4) with bisulfite more easily oxidized than sulfite. Therefore,keeping low pH level of the solution is conducive to the oxidation of total sulfite. The oxidation rate of total sulfite increases with air amount and temperature. The apparent activation energy for the overall oxidation is calculated to be 28 kJ·mol-1. A mathematical model was developed to simulate the process of oxidation of total sulfite and the calculated results show that this model agrees well with the experimental results of oxidation of total sulfite.