Test and Optimization of Cyclic Water Discharge Sewage Pretreatment System in Coal-fired Power Plant
The wastewater from the cyclic water discharge sewage of coal-fired power plants is complex in composition and has a high degree of pollutant enrichment.To improve the removal efficiency of calcium,magnesium,silicon,organic matter,and suspended solids in the water during the pretreatment processes,and to ensure the safe and stable operation of subsequent deep purification units,pretreatment methods such as"chemical softening+coagulation+sedimentation"were adopted for on-site simulation and optimization experiments on the pretreatment system of the cyclic water discharge sewage from a power plant in Norther China.The experimental results showed that the alkaline combination NaOH+Na2CO3 was more effective in reducing hardness of cyclic water discharge sewage and removing SiO2.When the optimal pH was controlled at 10.5,the effluent indicators were Ca2+≤50 mg/L,Mg2+≤80 mg/L,and SiO2≤1 mg/L.The order of dosing of the softening agent and coagulant did not significantly differ in the level of COD removal and sedimentation effect,with an average COD removal rate of 18.26％,and an SS removal rate of 60％.The concentration of the formed sludge(measured by SS concentration)was about 5 500 mg/L.Through the experimental research,the most suitable reagents,dosing order,and dosage were selected to provide data support for cost reduction and efficiency improvement in water treatment processes.The research results can provide a reference for the scheme design of zero discharge projects for power plant wastewater.
Coal-fired power plantcyclic water discharge sewagepre-processingexperimental researchcalcium magnesiumhardnessflocculant
万方数据
维普
