Removal Efficiency Of Magnesium Base-Seawater Desulfurization For Marine Flue Gas

With Shipping development, waste gas from diesel engine increases greatly, the environment has been badly polluted by the SO2 emission. Annex VI of MARPOL73/78 recently proposed strict standards that the sulfur content of fuel oil will reduce from 1.5% m/m to 1.0% m/m since the July 1,2010, and further to 0.1% m/m since the January 1,2015 in the Sulfur Emission Control Area.The traditional technologies for flue gas desulfurization (FGD) include dry circulating fluidized bed FGD, limestone-gypsum FGD, magnesium FGD, seawater FGD, plasma FGD and ammonia FGD, which are the most common treatments for removal of sulfur dioxide. Comparing with the advantages and disadvantages of them, and considering marine specific condition, it is believed that magnesium base-seawater desulfurization (M&S DeSOx) is the best method for processing marine flue gas. Summarizing common mechanism of wet desulfurization and the unique mechanism of magnesium desulfurization and seawater desulfurization, it is concluded that the main factors for removal efficiency of SO2 are flue flow, spray flow and pH value.The test system of M&S DeSOx has been established on a container ship, which includes an induced draft fan system, a spray system, pH control system and SO2 test system and etc. It is suitable for marine flue gas desulfurization with small footprint, high efficiency, no secondary pollution, and etc.In the experiment, MgO powder with the size of 200 meshes is used to obtain Mg(OH)2 serosity by hydration. Using orthogonal experiment to clarify the serosity activity, the conversion rate of Mg(OH)2 is up to 97% under optimal condition.In the M&S DeSO2 test, the effects of flow rate, spray flow rate and pH value on the removal efficiency of SO2 is studied experimentally. Beside of single factor analysis, orthogonal experiment is used to obtain optimal program. The results show that the removal efficiency of SO2 is greater than 90%, and the concentration of SO2 is less than 30ppm in the exhaust gases. It meets the new standard (sulfur content less than 0.1% m/m).