The Study Of Wet Flue Gas Desulfurization Process New Additive

SO₂ pollution has become an important factor to restrict the healthy development of national economy, Limestone / lime is cheap, they are widely used in WFGD (wet flue gas desulfurization). When additives are added into the desulfurization liquid, it can effectively improve the liquid phase mass transfer coefficient, increase their rate of utilization and desulfurization efficiency, meanwhile, it can prevent scale formation and buffer the liquid. Therefore the research of desulfurization liquid additives has attracted much attention.The new additives are researched and developed by means of complex with anionic surfactant SDS (sodium dodecyl sulfate), the amphoteric DSB (dodecyl sulfo betaine) and nonionic surfactant TX-100(TritonX-100). The surface-tensions of the desulfurization liquid with different proportion SDS, DSB and TX-100 are measured, and interactions between complex systems was studied, Na2SO4 and NaCl and their concentrations influence on surface properties of the complex system are discussed. The result has shown that synergistic effect of SDS-DSB complex system is obvious to reduce surface-tension and generating micelle. When mole ratio of SDS:DSB is 3:2, the surface-tension and cmc (critical micelle concentration) of complex systems are reduced to the minimum, while the synergy was up to the strongest; the Sodium salt can promoted micelle formation, its effect is Na2SO4 > NaCl. The new additives are determined as mole ratio of SDS:DSB is 3:2, added Na2SO4 (0.01mol/L) into hybrid system and studied the desulfurization properties.A micro simulation WFGD experiment device was designed according to the principle of proportion amplification, the device is tested and adjusted by a lot of experiments and experience, suitable operation parameters are determined. This provided experimental system for the new additive use in wet desulfurization.By simulating the WFGD slurry on Mini-simulated device, Firstly new additive influence on the liquid limestone H₂SO₄ solubility is researched. The result has shown the new additive promote limestone liquid's H₂SO₄ dissolving under pH 5.3, reduce surface-tension and cmc value of saturated CaCO₃ liquid, improve CaCO₃ solubility up to 8.88 mmol/L, which raises nearly 9 times than no additive. Secondly new additive on limestone desulfurization properties is studied. The result has shown that the new additive can obviously improve the absorptivity of SO₂. As the new additive concentration is 10mmol/L, desulfurization efficiency improve 5%, to 93.6%, the effect is the best. It enhances the buffering capacity of limestone desulfurization liquid, and stabilizes pH 5.3. Finaly economic and technical are analyzed according to the 300MW set calculation, after desulfurization liquid added new additive, the desulfurization cost year-on-year declines 6.90% with the same operating conditions. The subject has some practical reference value to the surfactant using in WFGD industry.