烟气脱硫中亚硫酸钙铁锰复合催化氧化优化

Oxidation of calcium sulfite is a very important part of wet limestone/gypsum flue gas desulfurization (FGD) process. Optimization of the oxidation process will help reduce energy consumption and cost. We studied standard oxidation rate (SOR) of calcium sulfite by Fe catalyst, Mn catalyst and Fe/Mn combined catalyst. Single factor analysis and response surface methodology were employed to study separate and joint effects of pH, Fe/Mn ratio and initial CaSO₃ concentration (ICS) on SOR. The results showed that combined catalyst resulted in a higher SOR than only Fe or Mn. ICS had the most impact on SOR, followed by pH and Fe/Mn ratio. Fe/Mn ratio and ICS had the most significant interaction. Optimum conditions for CaSO₃ oxidation were: pH of 4.5, Fe/Mn ratio of 0.37 and ICS of 17.83 mmol•L^-1. Under the optimum conditions, SOR reached 4.22 mmol•(L•min)^-1. The results from structural analysis indicated that the (020), (021) and (041) faces of the product CaSO₄•2H₂O were first formed in the oxidation process.