New hydrocyclone design for high starch yield: Effect of cylindrical-conical length proportion on the starch, sulfur and protein separation efficiencies

Abstract This research aimed to develop a new hydrocyclone design that matches the desired capacity and starch properties in each refining stage of cassava starch production process. The designed hydrocyclone dimension was adjusted to the proportion of cylindrical-conical length (L cy /L co ratio) at 0.00–0.14 and underflow-overflow diameter (D u /D o ratio) at 0.25–0.67 to yield a better starch-impurity separation efficiency. The L cy /L co dimensions affected the pressure drop (ΔP) within the hydrocyclone, while D u /D o affected the underflow discharge shape. An L cy /L co ratio of 0.11 and a D u /D o ratio of 0.67 provided the highest starch-impurity separation efficiency for the refining unit, but a D u /D o ratio of 0.25 was more suitable for the starch recovery from wastewater with a low concentration of starch (2.78% (w/v)), due to the high solid content of the underflow. The starch, sulfur and protein separation efficiencies of the newly designed hydrocyclone were 88.5–91.0%, 81.1–82.2% and 88.8–90.4%, respectively.