Experimental Study On Separation Of Gypsum Hydro-cyclone

The method of limestone/gypsum flue gas desulfurization(FGD), which has highdesulfurization efficiency, technical maturity, a wide range of processing capacity, awide distribution of the desulfurizer and recyclable byproducts, etc., has become themost effective and widely used technology to control SO2emissions of the coal-firedpower plants. As a kind of separation device which uses centrifugal sedimentation toseparate heterogeneous mixture, the hydro-cyclone is applied to the stage of gypsumslurry dehydration in the FGD gypsum dewatering system. The gypsum hydro-cyclonehas simple structure but the flow distribution inside is very complex. In the practicalengineering application, problems like low rate of underflow solids, poor classificationaccuracy, plugging and fluctuation of working conditions often occur. These issues havea direct or indirect relationship with the structural parameters and operating parametersof the cyclone.Therefore, through experimental study of the influences of structuralparameters, operation parameters and physical parameters on the separationperformance, guidance can be provided to actual industrial production and optimizationof operation parameters.Gypsum hydro-cyclone is the object of study in this paper, systematic research ofits separation performance was carried out through experiments. The media andworkflow of the hydro-cyclone in the flue gas desulfurization system in actual powerplant were simulated. A test device was constructed. Comprehensive and systematicexperiments of the parameters influencing separation performance were carried out onthe test device, and sufficient experiment data was obtained. The following factors ashydro-cyclone underflow diameter, inlet pressure and inlet concentration that mightinfluence the separation performance of the hydro-cyclone were performed factoranalysis. Results show that: Slurry treatment capacity depends mostly on inlet pressure,and a quadratic curve relationship can be observed between them; split ratio andseparation efficiency increased as the underflow diameter increased, but the underflowconcentration lowered; separation accuracy remain high within a proper range of theinlet pressure. In the premise of ensuring underflow concentration is higher than50%,separation performance was optimal when the inlet concentration was around16%andthe underflow pipe diameter being23mm. Under this condition, the Split ratio was lessthan0.16, and the separation accuracy was pretty high. The experimental condition on the test device was similar with actual productionline. The influences of underflow diameter, inlet pressure and inlet concentration on theunderflow concentration, overflow concentration, split ratio and separation efficiencywere analyzed through experiments. Data obtained were then processed using similaritycriterion equation. MATLAB software was then used to fit multi-factor mathematicalmodels using the processed data. Then error analysis was applied to these models.Typical orthogonal test results were selected and comparison were made between somedifferent operating points. And the results showed that the model was with highaccuracy, and it can satisfy practical engineering needs. In practical production,treatment capacity is usually high, incision granularity is usually small, it is hard to meetthe requirements with only one hydro-cyclone. In order to solve the problem, severalhydro-cyclones with smaller specification can be paralleled to meet the demands. Aperformance optimization scheme was proposed according to the analysis of the model,thus instruction can be offered to optimize engineering application.