Study On Hydrocyclone Separation Technology For Wastewater From Waterworks

With the rapid development of society and population growth,the scale of urban water supply has been increasing,The wastewater from waterworks has also increased dramatically.Treatment of wastewater from waterworks has some problems during the operation.A pilot experiment was carried out to study on hydrocyclone separation technology for water from waterworks,including the hydrocyclone for separation of wastewater from waterworks with the hydrocyclone' s internal flow field and concentration field of the change law.The purpose of hydrocyclone is to provide theoretical basis and technical support for the efficient concentration of wastewater.Main conclusions of the study are as follows;Separation performance studies show:with the import flow increasing,the concentration of underflow concentrates increased and then decreased,when the inlet flow rate was 2.3m3/h,reaching a maximum value of 2.54.The import flow rate was for importing fine particles in terms of classification efficiency.The flow rate was 2.6m3/h and the fractionation efficiency was close to 100%.The solid phase concentration of the feed increased and the separation efficiency decreased.The maximum separation efficiency of 36.27%occurred at a,concentration of 2.9g/L.When the diameter of the overflow pipe increased from 15mm to 23mm,the concentration of underflow concentration increased from 1.67 to 2.98,the separation efficiency increased by 11.33%,and the overflow pressure drop increased by 0.036 MPa.The reduction of the cone angle was beneficial to the solid-liquid separation.When the cone angle was 6°,the concentration of the underflow and the separation efficiency reached a maximum which were 2.57 and 30.17%,respectively.The diameter of the underflow pipe had a large influence on the split ratio.When the diameter of the underflow pipe expanded from 4mm to 8mm,the split ratio increased by 13.48%,and the separation efficiency increased,but the underflow pipe diameter was too large to cause a lower concentration of underflow.The PIV test results of the internal speed field of the hydrocyclone show:with the inlet flow rate increasing,the tangential velocity increased,and the radial velocity did not change significantly.When inlet flow rate was 2.6m3/h,the maximum tangential velocity on the section I of the cylindrical section was 2.589m/s and section II on the cone section was 1.337m/s.Near the center of the cyclone,the axial velocity had an increasing trend as the inlet flow rate increased;the influence of the bottom flow tube diameter on the axial velocity had less influence on the area outside the zero-axial velocity envelope(LZVV),and within the LZVV.The axial velocity of the zone increased with the increase in the diameter of the bottom tube.When the diameter of the bottom tube was 4mm,the maximum axial velocity at the center of the cross-sections I and II was 1.058m/s and 0.709m/s,respectively.As the diameter of the underflow tube increased,the tangential velocity decreased and the radial velocity increased.The on-site test results of the concentration field and pressure field of the hydrocyclone show:with the inlet flow increasing,the pressure increased;import flow for concentration distribution,the concentration decreased when the import flow increased near the hydrocyclone center.With the diameter of the bottom tube increasing,the pressure decreased significantly;the diameter of the bottom tube influenced the concentration distribution.When the diameter of the bottom tube increased from 4mm to 8mm,at the center position on section I,the concentration increased from 1.97g/L to 2.33g/L.