Effect Of Organic Pollutants On The Foaming Of Limestone Gypsum Desulfurization Tower

During the operation of limestone gypsum wet flue gas desulfurization(FGD),the bubble overflow phenomenon of the absorber tower is often occurred.After the absorption tower of circulating slurry foaming,liquid level meter display level far more than the real level,plus the influence of other factors,the circulating slurry liquid level fluctuation becomes larger,resulting in intermittent overflow of absorption tower.With the increase of foaming phenomenon,absorption tower of circulating slurry overflow excessive flow,the slurry can not be discharged through the overflow pipe,the bubble will poured into the raw gas flue,booster fan,will bring the desulfurization efficiency decreased,the quality of gypsum decreased,booster fan operation safety problems,affecting the stability and safe operation of the desulfurization system.The absorber slurry bubble overflow phenomenon will not only reduce the desulfurization efficiency,pollution of the environment,but also cause corrosion of the surrounding equipment,the desulfurization system outage and the displacement of the absorption tower slurry in serious situation.In this paper,the phenomenon of the absorber tower slurry overflow,the harm of foaming and the cause of foaming are analyzed,the main effects of foaming for organic pollutant,the chemical oxygen demand in the slurry volume(COD),total organic carbon(TOC)and total carbon(TC)to study the effects of foaming.Draw the following conclusions:1.The content of COD in the slurry affects slurry foaming,the content of slurry COD low to tens of milligrams per liter without foaming,and the COD value of slurry foaming in 300-600mg/L;COD is not the only influence factors of slurry foaming,anti foaming agent is added to a certain extent reduced the COD value of slurry,but is not significantly reduced;foaming have certain time accumulation.It is some degree lag that anti foaming agent to join defoaming.A portion of the slurry COD is determined by the limestone slurry COD;the COD in the slurry is constantly accumulating by the desulfurization system has been working continuously.2.The content of TOC in the absorption tower was between 80 mg/L?310 mg/L,and the relationship between the TOC value of slurry and the foaming of slurry could not be obtained through the analysis.The possible reason was that the addition of defoaming agent affected the value of TOC.Correlation analysis that between COD and TOC of slurry with medium correlation.The influence factors of the foaming degree of slurry are not only the TOC of the slurry,the addition of defoaming agent only to a certain extent reduce the TOC value of the slurry.The absorber slurry TOC is mainly derived from the combustion of entrained organic particles in the exhaust gas.3.The TC content of the absorption tower slurry was between 113 mg/L.-353.3 mg/L,and the overall trend map of slurry TC and defoaming agent was consistent.The value of COD,TOC and TC of the two absorption tower was higher than that of the first absorption tower.So it can be concluded that the COD,TOC and TC in the slurry have some influence on the foaming of the slurry.Most of the absorption tower slurry TC comes from the unburned particles in waste gas,and some of them come from limestone slurry.