Research on the Practical Application of High Efficient Synergistic Removal System of SO2 and SO3

With the continuous promotion of ultra-low emission retrofitting, the treatment of SO3 in the flue gas of coal-fired power plants has gradually gained emphasis. Some studies have shown that SO3 in coal-fired flue gas can be effectively removed using alkali absorbents, but its actual industrial application has not yet been examined. Therefore, in this paper, a synergistic and efficient SO2 and SO3 removal system was constructed for a coal-fired unit, and emission tests were conducted. This removal system, by adding an extra Ca(OH)2 spray system in the original desulphurisation system, in order to achieve mixed spraying of limestone slurry and Ca(OH)2 slurry in the desulphurisation tower. The alkali-based absorber Ca(OH)2 is utilised for its own alkalinity and efficient absorption of SO2 and SO3 in order to achieve synergistic removal of SO2 and SO3.The emission tests were conducted and the test results showed that, after running the SO2 and SO3 synergistic removal system and shutting down a slurry circulation pump, the SO2 emissions can be guaranteed to meet the standards, and the SO3 emission reduction rate exceeds 65%. The system can simultaneously remove SO2 and SO3 while reducing the usage of limestone slurry. The pH of the limestone slurry is also maintained within the ideal range. This system holds promising prospects for future practical industrial applications and research value.