不同污泥斗倾角对竖式沉淀池沉降效果的影响

Influence of Different Sludge Hopper Inclination Angles on the Settling Effect of Vertical Sedimentation Tanks

在化工厂污水絮凝处理工艺中,沉淀池的设计和沉降效率是确保出水水质达标的关键。本研究使用Fluent软件,结合RNG k-ε湍流模型和Mixture多相流模型,全面评估了竖式沉淀池的污泥斗倾角对高浓度污水沉降效果的影响。研究主要通过考察沉淀池内部的污泥流速流线图、排水口悬浮颗粒(SS)浓度,以及污泥去除率的变化,从而揭示了斜板倾角变化对污泥的流动特性、沉降效率和污泥去除率的影响。结果表明,当污泥斗倾角从40°增加到60°时,沉淀池内涡旋变少,流速和流向分布较均匀,流场相对稳定,沉降效果提升;当污泥斗倾角从60°增大到70°时,在沉淀池底部和排水口上部出现较大涡旋,导致颗粒在水中的停留时间增加,影响出水水质,降低沉降效果。当污泥斗倾角为60°时,竖式沉淀池能达到最好的沉降效果。这一发现为化工厂竖式沉淀池设计提供了重要的指导,强调了合理选择污泥斗倾角在提高絮体沉降效率中的关键作用。

In the flocculation treatment process of chemical plant effluent,the design and settling efficiency of the settling tank are critical to ensure that the effluent quality meets the standard.In this study,the influence of the sludge hopper inclination angle of a vertical sedimentation tank on the settling effect of highly concentrated wastewater was comprehensively evaluated using Fluent software in combination with the RNG k-εturbulence model and the Mixture multiphase flow model.The study mainly examined the sludge flow velocity streamlines inside the sedimentation tank,the concentration of suspended particles(SS)at the outfall,as well as the variation of sludge removal rate,so as to reveal the effects of the change of inclination angle of the inclined plate on the flow characteristics of sludge,the settling efficiency and the sludge removal rate.The results showed that when the sludge hopper inclination angle was increased from 40°to 60°,the vortex in the sedimentation tank became less,the flow velocity and flow direction were more uniformly distributed,the flow field was relatively stable,and the sedimentation effect was improved;when the sludge hopper inclination angle was increased from 60°to 70°,a larger vortex appeared at the bottom of the sedimentation tank and the upper part of the drain,which led to an increase in the retention time of the particles in the water,affecting the quality of the effluent water and decreasing the sedimentation effect.When the sludge hopper inclination angle is 60°,the vertical sedimentation tank can achieve the best settling effect.This finding provides important guidance for the design of vertical sedimentation tanks in chemical plants,emphasizing the key role of reasonable choice of sludge hopper inclination angle in improving floc settling efficiency.