Study On The Oxidation Process Of Ammonium Sulfite

The emission reduction of SO2has been a focus of attention for years, in view of the noteworthy damage of SO2on the human health and the environment. With high efficiency and product utilization, ammonia desulfurization has a great application prospect on the emission reduction of SO2. As an important part of the ammonia desulfurization, the oxidation process of ammonium sulfite is desired to be enhanced, and the enhancement of oxidation rate of ammonium sulfite is quite beneficial to the promotion and application of the ammonia desulfurization.In this work, the study on the oxidation of ammonium sulfite has been carried out in a stirred tank reactor (STR) and a double stirred tank reactor (DSTR). In the STR, the oxidizing parameters such as the temperature(T) between40and70℃, the initial pH value between3.0and7.0, the flow rate of air(G) between50and400L/h, the initial concentration of ammonium sulfite(C) between0.1and0.6mol/L have been separately studied about their effects on oxidizing result, via single factor experiments. A suitable catalyst has been determined via comparison of the catalytic efficiency of different salts.In the DSTR, the oxidizing parameters such as N between600and1100r/min, the T between40and70℃, the pH between3.0and7.0, the G between50and400L/h, the C between0.2and0.6mol/L have been separately studied about their effects on oxidizing result via single factor experiments. Meanwhile, orthogonal tests were carried out to determine the optimal oxidizing conditions. The oxidation process of ammonium sulfite with high concentration was also studied.The experimental results indicate that the oxidation rate of ammonium sulfite increases with the increase of T, G-and N, while decreases with the increase of pH and C. Sulfuric acid cobalt was determined as the optimum catalyst, with an optimal concentration of2×10-4mol/L. The optimal oxidizing parameters were found as the reaction temperature of50℃, initial pH of5.5, the G of250L/h and the N of1100r/min. The oxidation of ammonium sulfite with high concentration was carried out with catalyst concentration of2×10-4mol/L, the reaction temperature of50℃, initial pH of8.0, the G of250L/h and the N of1100r/min, where oxidation rate of more than80%could be obtained in70min.