Wet FGD Process With Alkaline Industrial Wastewater Containing NaClO

Wet flue gas desulphurization (Wet FGD) as a kind of efficient technology, has been widely used, however, with the process is long running, it would causing the fluctuation of product quality became bigger and bigger, and the SO2fume emission can not be discharged standard. As the environmental protection requirements increasing gradually and the emission standards continuing to higher level, energy companies already unable to withstand the high environmental costs. Therefore, to develop the new technologies of desulfurization in order to reduce the cost of Wet FGD has become an emerging research direction at home and abroad.This study designs a new technology of desulfurization by a compound alkaline industrial wastewater containing NaCIO absorption solution, which could greatly cutting the cost of Wet FGD and turn the waste into treasure.According to national standards of the People’s Republic of China "sodium hypochlorite solution"(GB19106-2003),The alkaline industrial wastewater containing NaCIO were analyzed, By the results of assay determination:Active chlorine (by sodium hypochlorite convert) mass fraction is:9.3952%; The mass fraction of free alkali(by sodium hydroxide convert) is:0.5084%; The mole fraction is:0.1271mol/L; Calculate pH is about:12.66,and measured pH is:12.76;The chemical formation mechanism and mass transfer mechanism was analyzed; Series of experiments were conducted to do a tentative exploration in the feasibility of the chemical desulfurization by the alkaline industrial wastewater containing NaCIO; Finally, the main reaction equations of the Wet FGD process with alkaline industrial wastewater containing NaCIO were summarized.The studies of desulfurization in the small industrial scale of packed tower and rotating-stream-tray scrubber respectively found that some key factors have a regular affect to the removing efficiency of SO2, including:inlet SO2concentration, inlet exhaust gas velocity, liquid-gas ratio and the temperature of reaction. Comparison on their absorption was given. The overall result indicates that the best absorption efficiency in rotating-stream-tray scrubber is at the same level of which in packed tower, but the former has a larger elasticity of operation and shows the advantage over the industrial applicationsWith the comprehensive consideration of test result and working condition of practical project, the optimum operating parameters were confirmed, which provided the theoretical foundation and experiment evidence for the industry application. The test results of our investigation indicate that the average efficiencies of desulfurization could retain100%and94.0%respectively in packed tower and rotating-stream-tray scrubber as follow optimum operating parameters:The reaction temperature was25℃; The initial pH value of absorption solution was12.76; L/G was upon5.0L/m3and4.0L/m3respectively in packed tower and rotating-stream-tray scrubber; the concentration of SO2set at level of1430mg/m3.This study designs a new technology of desulfurization by a compound alkaline industrial wastewater containing NaCIO absorption solution, it was based on the judgment of the status of the SO2flue gas treatment and prospects of development.The new method has many obvious advantages such as high efficiency to desulphurization, low-cost absorbent, simple equipment, simple operation and easy to implement automatic control. So it has fine theoretical significance and application promotion prospect.