| At present clarification tank modification, most of them are add inclined tube/sheet in theprecipitation area to enhance the effect of spate separation, but the above transformation isaccording to design specification reference value, no specific reference standards. The studyof such problems, by using combination of the Fluent software simulation and experimentmethods, simulation clarification pool single inclined tube in different liquid level load, lengthof different equivalent grain size particle removal and precipitation temperature field turbulentkinetic energy distribution, test the same level load, different inclined tube length, drugdosage and the same inclined tube length, different level load, drug dosage of water qualityunder the water. Preliminary sure vortex clarification tank inclined tube design relatedparameters.(1) The simulation study on single inclined tube of vortex clarification tank1) The removal efficiency decreases with increasing liquid level load. Through simulationcompared qualitatively determine the best liquid level of the model ⅠI load range for3~5m3/(m~2·h), in this range, the rational use of flocculating agent guarantee flocculation grainlarge and dense, inclined tube removal efficiency highest99.42%.2) Removal efficiency with the increase of particle equivalent grain size are increased. Inthe same level load condition, to the different size removal effect of simulation found particlesequivalent grain size is bigger, remove the better, this coincides with the facts. Through thecontrast analysis to identify model Ⅰ in the best level load range, particle equivalent grain sizefor100~125μm when removal effect is good.3) All removal rate with the length of the inclined tube increases with the rise, but withinclined tube length increases, the increase of the removal rate in reducing; when the particleequivalent grain size bigger, inclined tube length to increase the contribution of removal ratereduced. This phenomenon is more apparent in the larger particle size. Then define mode I inthe best level load, drug dosage, inclined tube length is600~800mm has can satisfy thespate separation, the highest removal rate can reach99.42%.4) Model Ⅱ ratio model Ⅰ of the removal efficiency is high, but automatic discharging mudis not better than model Ⅰ.(2) The simulation study on settling region of vortex clarification tank1) Precipitation area do not set up the inclined tub e/sheet, flow field velocity distributiondisequilibrium, in precipitation area formation range huge vortex, and go against spateseparation.2) Precipitation area set inclined tube/sheet, the internal flow field velocity distribution equilibrium and no vortex, and create a good spate separation conditions.(3) Field experiment1) The same level load, with the increase of drug dosage, inclined tube is100cm and70cm of clarifier effluent turbidity and UV254are reduced, but difference becomes smaller. In thedrug dosage reaches a certain range, the flocculation effect better, particles compacting larger,easy to precipitation, this time the inclined tube length is70cm and100cm removal effect isclose. Thus determined the inclined tube length is60~80cm feasibility.2) The same inclined tube length, with the increase of drug dosage, flow is6m3/h and10m3/h (i.e. liquid level load for3m3/(m~2·h) and5m3/(m~2·h)) of clarifier effluent turbidityand UV254are lower, but both difference became smaller. With a range of drug dosageincreased, flocculation precipitation effect better, the water demand in certain circumstances,can increase throughput.3) Validated through the experiment drug dosage in appropriate conditions the inclinedtube length is shortened60~80cm of feasibility, and determine the length in the liquid levelload for3m3/(m~2·h) and5m3/(m~2·h) place effect and100cm the effects of phase close to. |
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