Secondary-fluid mixing method and mixer for coagulating procedure

Abstract

A secondary flow mixing method for the coagulation procedure features that after the coagulant is added to raw water, the raw water is flowing in the pipeline able to generate secondary flow for mixing under the action of secondary flow. Its apparatus is composed of a coagulant adding tube and a secondary flow pipe which may be a spirally coiled hard tube or a flexible tube wound on a cylindrical body.

Description

Technical field [0001] The invention relates to a solid-liquid separation technology applied in the field of water and waste water treatment, in particular to a secondary flow mixing method used in a coagulation process and secondary flow mixing equipment using the method. Background technique [0002] Coagulation is an important water and wastewater treatment unit, often used to remove suspended mineral particles, activated sludge, natural organic matter (NOM) and phosphorus in water. Coagulation can generally be divided into two steps: fast stirring and slow stirring. The fast stirring process is also called the mixing process, which corresponds to the coagulation reaction stage of the coagulation process, accompanied by the addition of coagulant, diffusion, hydrolysis, destabilization and coalescence of the original particles, etc.; slow stirring is to prevent The settlement of larger particles increases the probability of collision between particles, so as to generate l...

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Problems solved by technology

The velocity gradient of the flow field formed by this mixing method is very inhomogeneous, the velocity gradient in the area near the stirring paddle is large, and the velocity gradient in the fluid body area away from this area is small

In this way, when the tiny flocs formed in the main body area of ​​the fluid flow to the area near the stirring blade, they will be broken due to the large shear action, which is not conducive to the improvement of the mixing effect.

At the same time, the operating cost of mechanical stirring is high, and it is difficult to maintain due to the large number of moving equipment

In recent years, due to the excellent mixing performance, the tubular static mixer has been favored by domestic and foreign water treatment engineers and is widely used. However, the structure of the equipment is relatively complicated, the cost is high, and the pressure loss when the fluid flows through is relatively large

In addition, in order to simplify the operation, jet pumps or centrifugal pumps are also used for mixing, but the effect of this mixing is generally not ideal

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