Combined impeller stirring device and application thereof

A method for applying a combined impeller stirring device, wherein the combined impeller stirring device comprises a stirred tank, a stirring shaft disposed within the stirred tank, and at least two mixing impeller units disposed on the stirring shaft, wherein each mixing impeller unit of the at least two mixing impeller units comprises a first nested mixing impeller and a second nested mixing impeller;

• wherein
• the first nested mixing impeller comprises two helical blades and two fixed shafts, the two fixed shafts are arranged in a staggered manner and are fixedly connected to the stirring shaft, two ends of each helical blade of the two helical blades are respectively connected to the two fixed shafts such that the two helical blades are arranged in rotational symmetry, the second nested mixing impeller is located between the two fixed shafts and is fixedly connected to the stirring shaft, each fixed shaft of the two fixed shafts is provided with a plurality of second protrusions, and the plurality of second protrusions are arranged in a staggered manner on upper and lower sides of the each fixed shaft;
• the second nested mixing impeller comprises at least two bayonet-type blades;
• the at least two mixing impeller units are arranged at intervals in an axial direction of the stirring shaft, adjacent mixing impeller units of the at least two mixing impeller units are staggered by 90°, a height of the each mixing impeller unit is 0.25 to 0.80 times an inner diameter of the stirred tank, and a spacing between the adjacent mixing impeller units is 1.00 to 1.25 times the height of the each mixing impeller unit;
• a diameter of the first nested mixing impeller is 0.60 to 0.75 times the inner diameter of the stirred tank;
• and
• a plurality of baffles are uniformly distributed on an inner wall of the stirred tank and are arranged parallel to the stirring shaft;
• the method comprises:
• applying the combined impeller stirring device in a field of petrochemicals.