CN102417252A - Adjustable mechanical flocculation reaction method for enhancing coagulation by using grids - Google Patents

Abstract

The invention discloses an adjustable mechanical flocculation reaction method using a grid to strengthen coagulation, which relates to the field of water treatment, and aims to solve the problem that the existing water treatment uses stirring paddles for coagulation and cannot uniformly distribute energy in water. Method: 1. Set a grid in each area between the horizontal axis and the vertical axis on the blades of the first-stage stirring paddle and the second-stage stirring paddle, and the grid of each grid on the first-stage stirring paddle The diameter of the inscribed circle of the hole is 5-50 mm, the diameter of the inscribed circle of each grid on the secondary stirring paddle is 10-60 mm, and the diameter of the inscribed circle of each grid on the secondary stirring paddle should be The diameter of the inscribed circle of each grid on the first-stage stirring paddle is 5-15 mm; the number of rotations of the second-stage stirring paddle is 2-5 rpm, and the number of rotations of the second-stage stirring paddle is 1-3.5 revolutions per minute, and the revolutions of the three-stage stirring paddles are 0.5 to 2.5 revolutions per minute. The invention is used in industries such as water treatment and chemical industry.

Description

An adjustable mechanical flocculation reaction method using grid-enhanced coagulation

technical field

The invention relates to the field of water treatment, in particular to a mechanical stirring type flocculation reaction method.

Background technique

Coagulation means that in the process of water treatment in the water treatment industry, by adding a coagulant, hydrolysis produces a product with a high charge and a low degree of polymerization to compress the double electron layer, and after proper mixing and stirring, the colloidal particles in the water can overcome the repulsive force Combine together and form flocculation, which is beneficial for further sedimentation, air flotation or filtration treatment. Existing flocculation equipment is mainly divided into two categories: hydraulic agitation and mechanical agitation. Hydraulic agitation flocculation equipment cannot adjust operating parameters according to water quality and quantity, and has poor adaptability. At present, the most commonly used flocculation equipment is mechanical agitation. The scheme can adjust the speed and other parameters according to the water quality and quantity, but the mechanical stirring paddle (see Figure 2) cannot evenly distribute the energy in the water, and the velocity gradient near the paddle blade is large, which is easy to break the formed flocs. The area between the horizontal axis and the vertical axis on each blade is not sufficiently disturbed, and the flocs cannot grow fully. In order to solve the problems of floc breaking and flocs not growing fully, some are installed perpendicular to the direction of water flow in the flocculation tank. Fixed grid, but the fixed grid cannot be adjusted according to the raw water conditions, the disturbance is insufficient when the water volume is low, and the energy input cannot be increased to promote the formation of flocs when the water temperature is low, and the disassembly and installation are complicated, which is limited in practical application; Some water plants strengthen the coagulation process by adjusting the pH of raw water, increasing the dosage of coagulants, and using coagulants and coagulants. However, increasing the dosage of coagulants and adjusting pH will increase pollution on the one hand. The amount of mud and the residue of water treatment chemicals increase the operating cost of water treatment on the other hand.

Contents of the invention

The purpose of the present invention is to solve the existing water treatment using mechanical agitation flocculation method, using stirring paddles for coagulation, because there is a transparent area between the horizontal axis and the vertical axis on the two paddles, this area cannot Evenly distributing energy in water leads to insufficient disturbance and insufficient growth of flocs. An adjustable mechanical flocculation reaction method using grids to strengthen coagulation is provided.

The method of the present invention is realized through the following steps: the method is realized based on a mechanical flocculation reaction tank, and the mechanical flocculation reaction tank has three stages, which are respectively a primary flocculation reaction pond, a secondary flocculation reaction pond and a tertiary flocculation reaction pond The reaction tank, the first-level flocculation reaction tank, the second-level flocculation reaction tank and the third-level flocculation reaction tank are arranged sequentially from the water inlet of the flocculation tank to the water outlet of the flocculation tank. There is a stirring paddle in each level of flocculation tank. The corresponding agitating paddles in the secondary flocculation reaction tank and the tertiary flocculation reaction tank are the primary agitating paddle, the secondary agitating paddle and the tertiary paddle; step 1, laying the primary paddle and the secondary agitating paddle on the grid: A grid is set in each area between the horizontal axis and the vertical axis on the blades of the first-stage stirring impeller and the second-stage stirring impeller, and the surrounding of each grid is connected with its corresponding horizontal axis and vertical axis , the diameter of the inscribed circle of each grid on the primary stirring paddle is 5 mm to 50 mm, the diameter of the inscribed circle of each grid on the secondary stirring paddle is 10 mm to 60 mm, and the diameter of the inscribed circle of each grid on the secondary stirring paddle is 10 mm to 60 mm. The diameter of the inscribed circle of each mesh of each grid should be greater than the diameter of the inscribed circle of each grid on the first-stage stirring paddle by 5mm to 15mm; Step 2. Determine the number of revolutions of the stirring paddles at each level: The number of revolutions of the paddle is 2 rpm to 5 rpm, the number of revolutions of the second-stage stirring paddle is 1 rpm to 3.5 rpm, and the number of revolutions of the third-stage stirring paddle is 0.5 rpm to 2.5 rpm .

Compared with the prior art, the present invention has the following beneficial effects: one, the present invention is provided with grid 2 on the primary stirring paddle and the secondary stirring paddle of mechanical flocculation reaction tank, and grid 2 can be used as solid phase medium in water The coagulation core can destroy the colloidal hydration film at the same time, generate a large number of micro-vortices that are beneficial to coagulation, and can distribute energy more evenly into the water. Therefore, the disturbance is sufficient and the flocs can fully grow, especially suitable for low-temperature and low-turbidity water. Enhanced treatment. 2. The mesh apertures of the grid 2 on the first-stage stirring paddle and the second-stage stirring paddle of the present invention are successively increased, which can obviously improve the coagulation effect, reduce the dosage of coagulant by 15-20%, and save water treatment costs. 3. The present invention can significantly reduce the dosage under the condition of the same effluent water quality, and has the advantages of small investment and convenient installation and maintenance.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the first-stage or second-stage agitator with a grid 2 installed on the agitator, and Fig. 2 is a schematic diagram of the structure of the existing mechanical agitation type agitator.

Detailed ways

Specific embodiment 1: This embodiment is described in conjunction with Fig. 1. This embodiment is realized through the following steps: This embodiment is realized based on a mechanical flocculation reaction tank. , the secondary flocculation reaction pool and the third-stage flocculation reaction pool; , the water in the second-level flocculation reaction tank and the third-level flocculation reaction tank are connected, and there is one stirring paddle in each level of flocculation reaction tank, and the corresponding stirring paddles in the first-level flocculation reaction tank, the second-level flocculation reaction tank and the third-level flocculation reaction tank are respectively One-stage stirring paddle, two-stage stirring paddle and three-stage stirring paddle; step 1, laying the first-stage stirring paddle and the second-stage stirring paddle on the grid 2: respectively on the paddle 1 of the first-stage stirring paddle and the second-stage stirring paddle A grid 2 is set in each area between the horizontal axis 1-1 and the vertical axis 1-2, and the surroundings of each grid 2 are bound and welded with the corresponding horizontal axis 1-1 and vertical axis 1-2 Or connected by connecting elements, the diameter of the inscribed circle of each grid 2 on the primary stirring paddle is 5mm-50mm, and the diameter of the inscribed circle of each grid 2 on the secondary stirring paddle is 10mm-60mm The diameter of the inscribed circle of each grid 2 on the secondary stirring paddle should be greater than the diameter of the inscribed circle of each grid 2 on the primary stirring paddle by 5mm to 15mm. For a new mechanical flocculation tank, the grid The mesh inscribed circle diameter of net 2 can be selected smaller value, for the transformation of existing mechanical flocculation pond, the mesh inscribed circle diameter of grid 2 is selected correspondingly larger; Number: the number of rotations of the first-stage stirring paddle is 2 rpm to 5 rpm, the rotation number of the second-stage stirring paddle is 1 rpm to 3.5 rpm, and the rotation number of the third-stage stirring paddle is 0.5 rpm ~2.5 rpm. The speed of the stirring paddle can be automatically adjusted according to the test results of the power tester connected to the stirring paddle motor. When the reading of the power meter is lower than the set value, the speed of the stirring paddle is increased; when the reading of the power meter is higher than the set value, the speed of the stirring paddle is reduced. Rotational speed; the area and mesh size of the added grid on the agitator can be adjusted according to the change of water quality, water temperature and water volume. When the water temperature is low, the set value of the power meter is increased, and the increased grid area on the agitator should be increased and a large mesh should be used. grid.

Specific embodiment two: this embodiment is described in conjunction with Fig. 1, each grid 2 is made up of stainless steel outer frame 2-1 and stainless steel wire mesh 2-2 in the step one of this embodiment, and stainless steel wire mesh 2-2 is surrounded by stainless steel wire mesh 2-2. Outer frame 2-1 welding. Other steps are the same as in the first embodiment.

Specific Embodiment Three: This embodiment is described with reference to FIG. 1 . The mesh of the stainless steel wire mesh 2-2 in this embodiment is rectangular, triangular or polygonal. Other steps are the same as in the first embodiment.

Specific Embodiment Four: This embodiment is described in conjunction with FIG. 1 . The diameter of the stainless steel wire on the stainless steel wire mesh (2-2) of this embodiment is 0.8 mm to 5 mm. For the new mechanical flocculation tank, the diameter of the stainless steel wire is slightly thicker. For the transformation of the existing mechanical flocculation tank, the diameter of the stainless steel wire can be thinner to reduce resistance and weight and avoid excessive changes to the original system. Other steps are the same as in the first embodiment.

Specific Embodiment Five: This embodiment is described in conjunction with FIG. 1. In step one of this embodiment, in each area between the horizontal axis 1-1 and the vertical axis 1-2 on the paddle 1 of the third-stage stirring paddle A grid 2 is set, and the surroundings of the grid 2 are bound, welded or connected to the corresponding horizontal axis 1-1 and vertical axis 1-2, and the meshes of each grid 2 on the three-stage stirring paddle The diameter of the cut circle is 20mm-70mm, and the diameter of the inscribed circle of each grid 2 on the third-stage stirring paddle should be greater than the diameter of the inscribed circle of each grid 2 on the second-stage stirring paddle by 10mm. Other steps are the same as in the first embodiment.

Application example of the present invention:

This example is a newly built water plant, the size of the flocculation tank is: length × width × height = 6.3m × 4.3m × 4.6m, horizontal shaft stirring impeller. Retrofit the first-stage stirring paddle and the second-stage stirring paddle; set them in each area between the horizontal axis 1-1 and the vertical shaft 1-2 on the paddle 1 of the first-stage stirring paddle and the second-stage stirring paddle respectively A grid 2, the diameter of stainless steel wire is 1.5mm, the mesh aperture of each grid 2 is 25mm based on the diameter of the inscribed circle of the mesh, and the size of the stainless steel outer frame 2-1 is: length × width = 4mm × 3mm ; The motor frequency is 18HZ, the motor line current is 3.5A, and the motor speed is 2.4 rpm. The results of the above simulation experiments are as follows: after adding grid 2, when the dosage is 60mg/L, the coagulation effect in the flocculation tank is close to the effect when the dosage is 80mg/L without adding grid; Finally, when the dosage is 70mg/L, the coagulation effect in the flocculation tank exceeds the effect when the dosage is 80mg/L without adding a grid. Experiments prove that under the condition of the same water quality, the method of the present invention can save 15% to 20% of the input amount of coagulant, and after increasing the grid, the energy consumption increases little under the condition of similar energy consumption.

Claims (5)

1. adjustable mechanical flocculation reaction method of utilizing the graticule mesh enhanced coagulation; Said method realizes through following steps: said method realizes based on mechanical flocculation tank; Said mechanical flocculation tank has three grades; Be respectively one-level flocculation tank, secondary flocculation tank and three grades of flocculation tanks; One-level flocculation tank, secondary flocculation tank and three grades of flocculation tanks are set gradually by flocculation basin feed-water end to flocculation basin water side; A stirring rake is arranged in every grade of flocculation basin, and corresponding stirring rake is respectively one-level stirring rake, secondary stirring rake and three grades of stirring rakes in one-level flocculation tank, secondary flocculation tank and the three grades of flocculation tanks; It is characterized in that: step 1, one-level stirring rake and secondary stirring rake are laid graticule mesh (2): in the transverse axis (1-1) on the blade (1) of one-level stirring rake and secondary stirring rake and each zone between the vertical axes (1-2) graticule mesh (2) is set respectively; The transverse axis (1-1) corresponding with it is connected with vertical axes (1-2) around each graticule mesh (2); The mesh inscribed circle diameter of each graticule mesh (2) on the one-level stirring rake is 5mm～50mm; The mesh inscribed circle diameter of each graticule mesh (2) on the secondary stirring rake is 10mm～60mm, and the mesh inscribed circle diameter of each graticule mesh (2) on the secondary stirring rake should be greater than the mesh inscribed circle diameter 5mm～15mm of each graticule mesh (2) on the one-level stirring rake; Step 2, confirm the revolution of stirring rakes at different levels (1): the revolution of one-level stirring rake is 2 rev/mins～5 rev/mins, and the revolution of secondary stirring rake is 1 rev/min～3.5 rev/mins, and the revolution of three grades of stirring rakes is 0.5 rev/min～2.5 rev/mins.

2. according to the said a kind of adjustable mechanical flocculation reaction method of utilizing the graticule mesh enhanced coagulation of claim 1; It is characterized in that: each graticule mesh (2) is made up of stainless steel housing (2-1) and Stainless Steel Cloth (2-2) in the said step 1, and Stainless Steel Cloth (2-2) welds with stainless steel housing (2-1) all around.

3. according to the said a kind of adjustable mechanical flocculation reaction method of utilizing the graticule mesh enhanced coagulation of claim 2, it is characterized in that: the mesh of said Stainless Steel Cloth (2-2) is rectangle, trilateral or Polygons.

4. according to claim 2 or 3 said a kind of adjustable mechanical flocculation reaction methods of utilizing the graticule mesh enhanced coagulation, it is characterized in that: the diameter of the Stainless Steel Wire on the said Stainless Steel Cloth (2-2) is 0.8mm～5mm.

5. according to the said a kind of adjustable mechanical flocculation reaction method of utilizing the graticule mesh enhanced coagulation of claim 1; It is characterized in that: in the transverse axis (1-1) in the said step 1 on the blade (1) of three grades of stirring rakes and each zone between the vertical axes (1-2) graticule mesh (2) is set; The transverse axis (1-1) corresponding with it is connected with vertical axes (1-2) binding, welding or connect elements around this graticule mesh (2); The mesh inscribed circle diameter of each graticule mesh (2) on three grades of stirring rakes is 20mm～70mm, and the mesh inscribed circle diameter of each graticule mesh (2) on three grades of stirring rakes should be greater than the mesh inscribed circle diameter 10mm of each graticule mesh (2) on the secondary stirring rake.

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