Method for enhancing chemical sludge dewatering

Abstract

The invention discloses a method for enhancing chemical sludge dewatering, which comprises the following steps: preparing quantitative treatment slurry, and pumping the treatment slurry to a sludge thickening tank through a dosing pump, the preparation method comprises the following steps: mixing 20-35 parts of limestone powder, 10-18 parts of limestone by-products, 4-7 parts of mud cake powder, 7-15 parts of desulfurized ash, 30-42 parts of liquid polyferric sulfate and 4-9 parts of hydrogen peroxide; to-be-treated sludge water is introduced into the sludge concentration tank, and a stirring system arranged in the sludge concentration tank is used for homogenizing and stirring the sludge water and the treated slurry; after the flocculent sludge in the sludge concentration tank is precipitated and concentrated, pumping the flocculent sludge to a sludge dewatering machine through a slurry pump, dewatering the flocculent sludge through the sludge dewatering machine, compressing a mud cake, and recycling the compressed mud cake and clear water.

Description

Technical Field

[0001] The invention relates to the field of chemical sludge dehydration for thermal power generation, in particular to a method for enhancing chemical sludge dehydration. Background Art

[0002] During the chemical water production process, thermal power plants add appropriate chemicals to combine tiny suspended matter and colloids in the water into large flocs, which are then precipitated under gravity, producing a large amount of sludge. The moisture content of this sludge is greater than 97%, and it needs to be dehydrated before the mud cake is transported out and the water is recycled.

[0003] At present, in order to improve the dewatering efficiency of sludge, the conventional method is to add limestone powder / solution to the sludge thickening tank to increase the sludge crystallization nuclei, accelerate and promote the growth of floccules, and reduce the moisture content of the mud cake after dehydration to 60%, thereby solving the problem of difficult dehydration of chemical sludge in thermal power plants or high moisture content of the mud cake after dehydration.

[0004] However, the method of using limestone powder / solution for conditioning and dehydration is slow in the efficiency of limestone powder / solution forming sludge crystal nuclei with sludge, and its dehydration performance is also poor. Based on this, the present invention proposes a method for enhancing chemical sludge dehydration, which can effectively improve the sludge dehydration effect, require less dosage of reagents, and can adjust the sludge pH, stabilize the dehydrated sludge, and reduce the risk of sludge disposal. In addition, the present invention reduces the use of limestone and sulfate by using limestone byproducts, mud cake powder, desulfurization ash, etc., further reducing the processing cost. Summary of the invention

[0005] The object of the present invention is to provide a method for enhancing chemical sludge dewatering to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for enhancing chemical sludge dehydration, comprising:

[0007] Step 1: preparing a quantitative treatment slurry, and pumping the treatment slurry to a sludge thickening tank through a dosing pump, wherein the treatment slurry comprises, by weight: 20 to 35 parts of limestone powder, 10 to 18 parts of limestone by-products, 4 to 7 parts of mud cake powder, 7 to 15 parts of desulfurized ash, 30 to 42 parts of liquid polyferric sulfate, and 4 to 9 parts of hydrogen peroxide;

[0008] Step 2: The sludge water to be treated is introduced into the sludge thickening tank, and the stirring system configured in the sludge thickening tank homogenizes and stirs the sludge water and the treated slurry;

[0009] Step 3: After the flocculent sludge in the sludge thickening tank is precipitated and concentrated, the flocculent sludge is pumped to the sludge dewatering machine through a mud pump, and the sludge dewatering machine performs dehydration, mud cake compression and clean water reuse.

[0010] Preferably, the preparation process of the treated slurry in step 1 includes: weighing raw materials according to the following weight parts, including 22 parts of limestone powder, 12 parts of limestone by-product, 5 parts of mud cake powder, 9 parts of desulfurization ash, 36 parts of liquid polyferric sulfate, and 6 parts of hydrogen peroxide; first placing the limestone powder, mud cake powder, and desulfurization ash in a reaction container, and then adding liquid polyferric sulfate and hydrogen peroxide for neutralization reaction, that is, the CaO and Fe2O3 contained in the limestone powder, mud cake powder, and desulfurization ash will be neutralized with the acid solution of polyferric sulfate; after the reaction is completed, the limestone by-product is added, and the treated slurry is obtained after homogenization and stirring.

[0011] Preferably, the limestone by-product includes a coarse product and a fine product, wherein the coarse product refers to particles larger than or equal to 0.05 mm, and the coarse product is treated with a pore-forming agent and then immersed in an oxyhydroxide solution to obtain the product.

[0012] Preferably, the fine product refers to a colloidal polymer formed by adding colloid after calcining and grinding particles smaller than 0.05 mm, wherein the colloid is a metal hydroxide colloid.

[0013] Preferably, the mud cake powder in the treatment slurry formula is obtained by dehydrating, pressing and carbonizing chemical sludge at high temperature.

[0014] Preferably, the desulfurization ash is a powdery substance processed by a grinder.

[0015] Preferably, the sludge dewatering machine is a plate and frame filter press, the dehydration pressure of which is 1 to 2 MPa and the dehydration time is 20 to 30 min.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The method of the present invention can effectively improve the sludge dehydration effect, require less reagent dosage, and can adjust the sludge pH, stabilize the dehydrated sludge, and reduce the risk of sludge disposal. In addition, the present invention reduces the use of limestone and sulfate by using limestone byproducts, mud cake powder, desulfurization ash, etc., further reducing the treatment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Implementation diagram of the method of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1 The present invention provides a technical solution: a method for enhancing chemical sludge dehydration, comprising the steps of:

[0021] Step 1: preparing a quantitative treatment slurry, and pumping the treatment slurry to a sludge thickening tank through a dosing pump, wherein the treatment slurry comprises, by weight: 20 to 35 parts of limestone powder, 10 to 18 parts of limestone by-products, 4 to 7 parts of mud cake powder, 7 to 15 parts of desulfurized ash, 30 to 42 parts of liquid polyferric sulfate, and 4 to 9 parts of hydrogen peroxide;

[0022] Step 2: The sludge water to be treated is introduced into the sludge thickening tank, and the stirring system configured in the sludge thickening tank homogenizes and stirs the sludge water and the treated slurry;

[0023] Step 3: After the flocculent sludge in the sludge thickening tank is precipitated and concentrated, the flocculent sludge is pumped to the sludge dewatering machine through a mud pump, and the sludge dewatering machine performs dehydration, mud cake compression and clean water reuse.

[0024] In this embodiment, the preparation process of the treated slurry in step 1 includes: weighing raw materials according to the following weight parts, including 22 parts of limestone powder, 12 parts of limestone by-product, 5 parts of mud cake powder, 9 parts of desulfurization ash, 36 parts of liquid polyferric sulfate, and 6 parts of hydrogen peroxide; first placing the limestone powder, mud cake powder, and desulfurization ash in a reaction container, and then adding liquid polyferric sulfate and hydrogen peroxide for neutralization reaction, that is, the CaO and Fe2O3 contained in the limestone powder, mud cake powder, and desulfurization ash will be neutralized with the acid solution of polyferric sulfate; after the reaction is completed, the limestone by-product is added, and the treated slurry is obtained after homogenization and stirring.

[0025] In this embodiment, the limestone by-product includes a coarse product and a fine product, wherein the coarse product refers to particles larger than or equal to 0.05 mm, and the coarse product is treated with a pore-forming agent and then immersed in an oxyhydroxide solution to obtain the product.

[0026] In this embodiment, the fine product refers to a colloidal polymer formed by adding colloid after calcining and grinding particles smaller than 0.05 mm, and the colloid is a metal hydroxide colloid.

[0027] In this embodiment, the mud cake powder in the treatment slurry formula is obtained by dehydrating, pressing and carbonizing the chemical sludge at high temperature.

[0028] In this embodiment, the desulfurization ash is a powdery substance processed by a grinder.

[0029] In this embodiment, the sludge dewatering machine is a plate and frame filter press, the dewatering pressure is 1-2 MPa, and the dewatering time is 20-30 min.

[0030] Embodiment 1:

[0031] Step 1: prepare a quantitative treatment slurry, and pump the treatment slurry to the sludge thickening tank through a dosing pump, wherein the treatment slurry comprises, by weight: 25 parts of limestone powder, 12 parts of limestone by-product, 4 parts of mud cake powder, 8 parts of desulfurized ash, 32 parts of liquid polyferric sulfate, and 6 parts of hydrogen peroxide;

[0032] Step 2: The sludge water to be treated is introduced into the sludge thickening tank, and the stirring system configured in the sludge thickening tank homogenizes and stirs the sludge water and the treated slurry;

[0033] Step 3: After the flocculent sludge in the sludge thickening tank is precipitated and concentrated, the flocculent sludge is pumped to the sludge dewatering machine through a mud pump, and the sludge dewatering machine performs dehydration, mud cake compression and clean water reuse.

[0034] Embodiment 2:

[0035] Step 1: prepare a quantitative treatment slurry, and pump the treatment slurry to the sludge thickening tank through a dosing pump, wherein the treatment slurry comprises, by weight: 29 parts of limestone powder, 15 parts of limestone by-product, 6 parts of mud cake powder, 9 parts of desulfurized ash, 32 parts of liquid polyferric sulfate, and 6 parts of hydrogen peroxide;

[0036] Step 2: The sludge water to be treated is introduced into the sludge thickening tank, and the stirring system configured in the sludge thickening tank homogenizes and stirs the sludge water and the treated slurry;

[0037] Step 3: After the flocculent sludge in the sludge thickening tank is precipitated and concentrated, the flocculent sludge is pumped to the sludge dewatering machine through a mud pump, and the sludge dewatering machine performs dehydration, mud cake compression and clean water reuse.

[0038] Embodiment 3:

[0039] Step 1: prepare a quantitative treatment slurry, and pump the treatment slurry to the sludge thickening tank through a dosing pump, wherein the treatment slurry comprises, by weight: 27 parts of limestone powder, 18 parts of limestone by-product, 7 parts of mud cake powder, 9 parts of desulfurized ash, 35 parts of liquid polyferric sulfate, and 8 parts of hydrogen peroxide;

[0040] Step 2: The sludge water to be treated is introduced into the sludge thickening tank, and the stirring system configured in the sludge thickening tank homogenizes and stirs the sludge water and the treated slurry;

[0041] Step 3: After the flocculent sludge in the sludge thickening tank is precipitated and concentrated, the flocculent sludge is pumped to the sludge dewatering machine through a mud pump, and the sludge dewatering machine performs dehydration, mud cake compression and clean water reuse.

[0042]

[0043] The method of the above embodiment can effectively improve the sludge dehydration effect, require less reagent dosage, and can adjust the sludge pH, stabilize the dehydrated sludge, and reduce the risk of sludge disposal. In addition, the present invention reduces the use of limestone and sulfate by using limestone byproducts, mud cake powder, desulfurization ash, etc., further reducing the treatment cost.

[0044] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for enhancing chemical sludge dewatering, characterized in that: Includes steps: Step 1: preparing a quantitative treatment slurry, and pumping the treatment slurry to a sludge thickening tank through a dosing pump, wherein the treatment slurry comprises, by weight: 20 to 35 parts of limestone powder, 10 to 18 parts of limestone by-products, 4 to 7 parts of mud cake powder, 7 to 15 parts of desulfurized ash, 30 to 42 parts of liquid polyferric sulfate, and 4 to 9 parts of hydrogen peroxide; Step 2: The sludge water to be treated is introduced into the sludge thickening tank, and the stirring system configured in the sludge thickening tank homogenizes and stirs the sludge water and the treated slurry; Step 3: After the flocculent sludge in the sludge thickening tank is precipitated and concentrated, the flocculent sludge is pumped to the sludge dewatering machine through a mud pump, and the sludge dewatering machine performs dehydration, mud cake compression and clean water reuse.

2. A method for enhancing chemical sludge dewatering according to claim 1, characterized in that: The preparation process of the treatment slurry in step 1 includes: weighing raw materials according to the following weight parts, including 22 parts of limestone powder, 12 parts of limestone by-product, 5 parts of mud cake powder, 9 parts of desulfurization ash, 36 parts of liquid polyferric sulfate, and 6 parts of hydrogen peroxide; firstly placing the limestone powder, mud cake powder, and desulfurization ash in a reaction container, and then adding liquid polyferric sulfate and hydrogen peroxide for neutralization reaction, that is, CaO and Fe2O3 contained in the limestone powder, mud cake powder, and desulfurization ash will be neutralized with the acid solution of polyferric sulfate; after the reaction is completed, adding the limestone by-product, and preparing the treatment slurry after homogenization and stirring.

3. A method for enhancing chemical sludge dewatering according to claim 1, characterized in that: The limestone by-product includes a coarse product and a fine product, wherein the coarse product refers to particles larger than or equal to 0.05 mm, and the coarse product is treated with a pore-forming agent and then immersed in an oxyhydroxide solution to obtain the product.

4. A method for enhancing chemical sludge dewatering according to claim 1, characterized in that: The fine product refers to a colloidal polymer formed by adding colloid after calcining and grinding particles smaller than 0.05 mm, and the colloid is a metal hydroxide colloid.

5. The method for enhancing chemical sludge dewatering according to claim 1, characterized in that: The mud cake powder in the treatment slurry formula is obtained by dehydrating, pressing and carbonizing chemical sludge at high temperature.

6. A method for enhancing chemical sludge dewatering according to claim 1, characterized in that: The desulfurization ash is a powdery substance processed by a grinder.

7. The method for enhancing chemical sludge dewatering according to claim 1, characterized in that: The sludge dewatering machine is a plate-frame filter press, the dewatering pressure of which is 1-2 MPa, and the dewatering time is 20-30 min.

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