Industrial sludge conditioner and production process thereof

Abstract

The present invention relates to an industrial sludge conditioner and a production process thereof, and belongs to the technical field of sludge treatment. The industrial sludge conditioner is composed of a main agent and an auxiliary agent, wherein the main agent is the following components: 28-35wt% of starch derivatives, 3.5-5.5wt% of coagulants, 1.5-2wt% of coagulants and 1-1.4wt% of dispersants, the balance is water, and the auxiliary agent is a hydrogen peroxide solution; the starch derivative is modified by introducing active amino groups into starch pretreatment with a silane coupling agent KH550, and then quaternizing the grafted amino structure with 1-chloropropanol, and simultaneously introducing polyhydroxyl groups, and finally acetic anhydride reacts with the introduced hydroxyl groups for acetylation treatment, that is, obtaining a starch derivative, which interacts with hydrogen peroxide to play a "break gel-oxidation-reflocculation" role, and has a high-efficiency conditioning effect on sludge.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge treatment, and in particular relates to an industrial sludge conditioner and a production process thereof. Background Art

[0002] With the acceleration of industrialization, sewage treatment has become an important part of environmental protection. Sludge, as a by-product of sewage treatment, contains a large amount of organic matter, pathogens, heavy metals and other harmful substances. If it is not handled properly, it will cause serious pollution to the environment. Therefore, the treatment and resource utilization of sludge has become an urgent problem to be solved in the field of environmental protection.

[0003] Sludge usually carries a negative charge in its natural state. This negative charge is carried by the organic matter in the sludge and the extracellular polymers produced by microorganisms. These are polymers secreted outside the cells by microorganisms during their growth. They form a network between sludge particles, enhancing the electrostatic attraction between particles, causing the sludge particles to carry a negative charge. This negative charge makes it easy for sludge particles to repel each other, thereby hindering the flocculation and dehydration process of the sludge. In order to improve the dehydration performance of sludge, chemical conditioners are often needed to neutralize the negative charge of sludge particles, thereby promoting flocculation and dehydration. Commonly used chemical conditioners include cationic polyacrylamide, quaternary ammonium salts, etc. They neutralize the negative charge of sludge particles by providing positive charges, promoting mutual attraction and flocculation between particles. The biggest problem faced by this type of sludge conditioner is insufficient dispersibility and permeability, resulting in low conditioning efficiency and limited conditioning effect. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide an industrial sludge conditioner and a production process thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An industrial sludge conditioner consists of a main agent and an auxiliary agent, wherein the main agent is the following components: 28-35wt% starch derivative, 3.5-5.5wt% coagulant, 1.5-2wt% coagulant aid and 1-1.4wt% dispersant, and the balance is water; the auxiliary agent is a hydrogen peroxide solution.

[0007] The starch derivative is prepared by the following method:

[0008] Step A1: Mix silane coupling agent KH550 and ethanol solution, add acetic acid to adjust the pH value to 3.5-4.5 and stir to hydrolyze for 1-1.3 hours, add starch and mix well, then neutralize with ammonia water, let stand for 24 hours, take the bottom precipitate and vacuum dry to obtain intermediate 1;

[0009] Furthermore, the dosage ratio of starch, silane coupling agent KH550 and ethanol solution is 50g:1.5-2mL:55-70mL, the volume fraction of the ethanol solution is 30%, and the silane coupling agent KH550 condenses with the abundant hydroxyl groups in the starch molecules after hydrolysis, introducing silane structure and active amino modification into the starch molecules.

[0010] Step A2: premix 1-chloropropanol, potassium carbonate and acetone, add intermediate 1 and mix well, introduce nitrogen protection, heat to 45-55°C, stir and reflux at 120-150 rpm for 4-5 hours, and remove acetone by rotary evaporation after the reaction to obtain intermediate 2;

[0011] Furthermore, the usage ratio of intermediate 1, 1-chloropropanol, potassium carbonate and acetone is 50g:8-12mL:0.1-0.15g:60-80mL. Under the promotion of potassium carbonate, 1-chloropropanol replaces the grafted amino group in the intermediate 1 molecule to form a quaternary ammonium structure containing multiple hydroxyl groups.

[0012] Step A3: Mix the intermediate 2, aluminum chloride and dioxane, introduce nitrogen protection, control the temperature of the water bath to 50-60°C, apply stirring at 180-240 rpm, slowly add acetic anhydride to react for 1.5-2.2 hours, and remove dioxane by rotary evaporation after the reaction to obtain a starch derivative;

[0013] Furthermore, the usage ratio of intermediate 2, acetic anhydride, aluminum chloride and dioxane is 50 g: 2.2-2.8 mL: 15-20 mg: 40-50 mL, and acetic anhydride reacts with the hydroxyl group introduced into the intermediate 2 molecule to perform acetylation treatment.

[0014] Preferably, the coagulant is selected from polyferric sulfate.

[0015] Preferably, the coagulant aid is selected from sodium silicate.

[0016] Preferably, the dispersant is selected from polyether surfactants.

[0017] The invention discloses a production process of an industrial sludge conditioner, which specifically comprises the following steps: premixing a coagulant, a coagulant aid, a dispersant and water, adding a starch derivative and mixing evenly to form a main agent, and using a hydrogen peroxide solution as a single-component auxiliary agent.

[0018] Beneficial effects of the present invention:

[0019] The invention discloses a two-component sludge conditioner, wherein a starch derivative independently developed is introduced into a main agent, and hydrogen peroxide in an auxiliary agent interacts with each other, so as to effectively improve the dehydration property of sludge; the starch derivative is pretreated with a silane coupling agent KH550 to introduce a silane structure into starch molecules to inhibit starch gelatinization, and active amino groups are introduced for modification to obtain an intermediate 1; the amino structure grafted in the intermediate 1 molecule is subjected to a quaternization reaction by 1-chloropropanol, and polyhydroxy groups are introduced to obtain an intermediate 2; finally, acetic anhydride is reacted with the hydroxy groups introduced in the intermediate 2 molecule to perform an acetylation treatment, so as to obtain a starch derivative; in the sludge treatment process, the poly-branched quaternary ammonium cation structure in the starch derivative molecule breaks the stable negative charge in the sludge; The charge state is conducive to the precipitation of water in the sludge from the negatively charged colloid, and at the same time, the starch derivative is evenly dispersed in the colloid of the sludge. After that, the peroxide ion produced by the decomposition of the auxiliary agent has a strong nucleophilic attack ability, which reacts with the acetylated structure in the starch derivative molecule to produce peracetic acid, and the peracetic acid has a strong oxidizing property, which further oxidizes the colloid of the sludge and accelerates the in-depth dispersion of the starch derivative. The starch molecules after the acetylated structure is attacked by oxygen radicals adsorb the exposed sludge particles and re-flocculate and settle, so that water and sludge particles are separated, thereby achieving the effect of sludge conditioning. Compared with traditional sludge conditioners, the starch derivative developed by the present invention plays a role of "gel breaking-oxidation-re-flocculation", and has a high-efficiency conditioning effect on the sludge. DETAILED DESCRIPTION

[0020] The following will be combined with 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.

[0021] Example 1, preparation of industrial sludge conditioner, the specific implementation process is as follows:

[0022] (1) Preparation of starch derivatives

[0023] Step A1: prepare a 30% volume fraction ethanol aqueous solution, mix the silane coupling agent KH550 and the ethanol solution, add acetic acid to adjust the pH value to 3.5 and stir to hydrolyze for 1 hour, add starch and mix well, then neutralize with ammonia water, let stand for 24 hours, take the bottom precipitate and vacuum dry to obtain intermediate 1; wherein, the starch is commercially available industrial cassava starch, and the amount ratio of starch, silane coupling agent KH550 and ethanol solution is 50g:2mL:70mL.

[0024] Step A2: pre-mix 1-chloropropanol, potassium carbonate and acetone, add intermediate 1 and mix well, introduce nitrogen protection, heat to 55°C, stir and reflux at 150 rpm for 4 hours, and remove acetone by rotary evaporation after the reaction to obtain intermediate 2; wherein the amount ratio of intermediate 1, 1-chloropropanol, potassium carbonate and acetone is 50 g:12 mL:0.15 g:80 mL.

[0025] Step A3: Take intermediate 2, aluminum chloride and dioxane, mix them, introduce nitrogen protection, control the temperature of the water bath to 60°C, apply stirring at 240rpm, slowly add acetic anhydride, control the addition time to 40min, continue to stir at a constant temperature after complete addition, the total reaction time of acetic anhydride addition is 1.5h, and after the reaction is completed, remove dioxane by rotary evaporation to obtain a starch derivative; wherein the amount ratio of intermediate 2, acetic anhydride, aluminum chloride and dioxane is 50g:2.8mL:20mg:50mL.

[0026] (2) Preparation of industrial sludge conditioner

[0027] Preparation of the main agent: take the raw materials according to weight percentage, starch derivative 28wt%, prepared by this embodiment; coagulant 5.5wt%, commercially available polyferric sulfate is used in the implementation process, and the total iron content is 19%; coagulant 2wt%, commercially available sodium silicate is used in the implementation process, and the modulus is 3.3; dispersant 1wt%, commercially available T-3400B type polyether surfactant is used in the implementation process; water 65.3wt%; add the coagulant, coagulant, dispersant and water into a high-speed mixer, mix at a high speed of 1200rpm for 10min, then add the starch derivative, stir and mix at 60rpm for 1h to obtain the main agent;

[0028] Preparation of auxiliary agent: Take commercially available hydrogen peroxide, add water to prepare a 10% aqueous solution by mass, and use the hydrogen peroxide solution as a single component as an auxiliary agent; the main agent and the auxiliary agent are used together as industrial sludge conditioners during the treatment process.

[0029] Example 2, preparation of industrial sludge conditioner, the specific implementation process is as follows:

[0030] (1) Preparation of starch derivatives

[0031] Step A1: prepare a 30% volume fraction ethanol aqueous solution, mix the silane coupling agent KH550 and the ethanol solution, add acetic acid to adjust the pH value to 4.5 and stir to hydrolyze for 1.3 hours, add starch and mix well, then neutralize with ammonia water, let stand for 24 hours, take the bottom precipitate and vacuum dry to obtain intermediate 1; wherein, the starch is commercially available industrial cassava starch, and the amount ratio of starch, silane coupling agent KH550 and ethanol solution is 50g:1.5mL:55mL.

[0032] Step A2: pre-mix 1-chloropropanol, potassium carbonate and acetone, add intermediate 1 and mix well, introduce nitrogen protection, heat to 45°C, stir and reflux at 120rpm for 5h, and remove acetone by rotary evaporation after the reaction to obtain intermediate 2; wherein the dosage ratio of intermediate 1, 1-chloropropanol, potassium carbonate and acetone is 50g:8mL:0.1g:60mL.

[0033] Step A3: Take intermediate 2, aluminum chloride and dioxane, mix them, introduce nitrogen protection, control the temperature of the water bath to 50°C, apply stirring at 180rpm, slowly add acetic anhydride, control the addition time to 1h, continue to stir at a constant temperature after complete addition, the total reaction time of acetic anhydride addition is 2.2h, and after the reaction is completed, remove dioxane by rotary evaporation to obtain a starch derivative; wherein, the amount ratio of intermediate 2, acetic anhydride, aluminum chloride and dioxane is 50g:2.2mL:15mg:40mL.

[0034] (2) Preparation of industrial sludge conditioner

[0035] Preparation of the main agent: take the raw materials according to weight percentage, starch derivative 35wt%, prepared by this embodiment; coagulant 3.5wt%, commercially available polyferric sulfate is used in the implementation process, and the total iron content is 19%; coagulant 1.5wt%, commercially available sodium silicate is used in the implementation process, and the modulus is 3.3; dispersant 1.4wt%, commercially available T-3400B type polyether surfactant is used in the implementation process; water 58.6wt%; add the coagulant, coagulant, dispersant and water into a high-speed mixer, mix at a high speed of 1200rpm for 10min, then add the starch derivative, stir and mix at 60rpm for 1h to obtain the main agent;

[0036] Preparation of auxiliary agent: Take commercially available hydrogen peroxide, add water to prepare a 10% aqueous solution by mass, and use the hydrogen peroxide solution as a single component as an auxiliary agent; the main agent and the auxiliary agent are used together as industrial sludge conditioners during the treatment process.

[0037] Example 3, preparation of industrial sludge conditioner, the specific implementation process is as follows:

[0038] (1) Preparation of starch derivatives

[0039] Step A1: prepare a 30% volume fraction ethanol aqueous solution, mix the silane coupling agent KH550 and the ethanol solution, add acetic acid to adjust the pH value to 4 and stir to hydrolyze for 1.1 hours, add starch and mix well, then neutralize with ammonia water, let stand for 24 hours, take the bottom precipitate and vacuum dry to obtain intermediate 1; wherein, the starch is commercially available industrial cassava starch, and the amount ratio of starch, silane coupling agent KH550 and ethanol solution is 50g:1.8mL:65mL.

[0040] Step A2: pre-mix 1-chloropropanol, potassium carbonate and acetone, add intermediate 1 and mix well, introduce nitrogen protection, heat to 50°C, stir and reflux at 150rpm for 4.5h, and remove acetone by rotary evaporation after the reaction to obtain intermediate 2; wherein the amount ratio of intermediate 1, 1-chloropropanol, potassium carbonate and acetone is 50g:10mL:0.12g:70mL.

[0041] Step A3: Take intermediate 2, aluminum chloride and dioxane, mix them, introduce nitrogen protection, control the temperature of the water bath to 55°C, apply stirring at 240rpm, slowly add acetic anhydride, control the addition time to 50min, continue to stir at a constant temperature after complete addition, the total reaction time of acetic anhydride addition is 1.8h, and after the reaction is completed, remove dioxane by rotary evaporation to obtain a starch derivative; wherein the amount ratio of intermediate 2, acetic anhydride, aluminum chloride and dioxane is 50g:2.5mL:18mg:45mL.

[0042] (2) Preparation of industrial sludge conditioner

[0043] Preparation of the main agent: take the raw materials according to weight percentage, starch derivative 30wt%, prepared by this embodiment; coagulant 4wt%, commercially available polyferric sulfate is used in the implementation process, and the total iron content is 19%; coagulant 1.5wt%, commercially available sodium silicate is used in the implementation process, and the modulus is 3.3; dispersant 1.2wt%, commercially available T-3400B type polyether surfactant is used in the implementation process; water 63.3wt%; add the coagulant, coagulant, dispersant and water into a high-speed mixer, mix at a high speed of 1200rpm for 10min, then add the starch derivative, stir and mix at 60rpm for 1h to obtain the main agent;

[0044] Preparation of auxiliary agent: Take commercially available hydrogen peroxide, add water to prepare a 10% aqueous solution by mass, and use the hydrogen peroxide solution as a single component as an auxiliary agent; the main agent and the auxiliary agent are used together as industrial sludge conditioners during the treatment process.

[0045] Example 4, preparation of industrial sludge conditioner, the specific implementation process is as follows:

[0046] (1) Preparation of starch derivatives

[0047] Step A1: prepare a 30% volume fraction ethanol aqueous solution, mix the silane coupling agent KH550 and the ethanol solution, add acetic acid to adjust the pH value to 4 and stir to hydrolyze for 1.2 hours, add starch and mix well, then neutralize with ammonia water, let stand for 24 hours, take the bottom precipitate and vacuum dry to obtain intermediate 1; wherein, starch is commercially available industrial cassava starch, and the amount ratio of starch, silane coupling agent KH550 and ethanol solution is 50g:1.8mL:65mL.

[0048] Step A2: pre-mix 1-chloropropanol, potassium carbonate and acetone, add intermediate 1 and mix well, introduce nitrogen protection, heat to 55°C, stir and reflux at 150 rpm for 4.5 hours, and remove acetone by rotary evaporation after the reaction to obtain intermediate 2; wherein the amount ratio of intermediate 1, 1-chloropropanol, potassium carbonate and acetone is 50 g:10 mL:0.13 g:75 mL.

[0049] Step A3: Take intermediate 2, aluminum chloride and dioxane, mix them, introduce nitrogen protection, control the temperature of the water bath to 55°C, apply stirring at 240rpm, slowly add acetic anhydride, control the addition time to 1h, continue to stir at a constant temperature after complete addition, the total reaction time of acetic anhydride addition is 2h, and after the reaction is completed, remove dioxane by rotary evaporation to obtain a starch derivative; wherein, the amount ratio of intermediate 2, acetic anhydride, aluminum chloride and dioxane is 50g:2.6mL:20mg:45mL.

[0050] (2) Preparation of industrial sludge conditioner

[0051] Preparation of the main agent: take the raw materials according to the weight percentage, starch derivative 32wt%, prepared by this embodiment; coagulant 4.5wt%, commercially available polyferric sulfate is used in the implementation process, and the total iron content is 19%; coagulant 1.8wt%, commercially available sodium silicate is used in the implementation process, and the modulus is 3.3; dispersant 1.2wt%, commercially available T-3400B type polyether surfactant is used in the implementation process; water 60.5wt%; add the coagulant, coagulant, dispersant and water into a high-speed mixer, mix at a high speed of 1200rpm for 10min, then add the starch derivative, stir and mix at 60rpm for 1h to obtain the main agent;

[0052] Preparation of auxiliary agent: Take commercially available hydrogen peroxide, add water to prepare a 10% aqueous solution by mass, and use the hydrogen peroxide solution as a single component as an auxiliary agent; the main agent and the auxiliary agent are used together as industrial sludge conditioners during the treatment process.

[0053] Comparative Example 1, acetylated starch and quaternary ammonium salt were used to replace starch derivatives to prepare industrial sludge conditioner, and the specific implementation process was as follows:

[0054] Preparation of acetylated starch: Cassava starch and dioxane are stirred at high speed to form a slurry, nitrogen is introduced for protection, acetic anhydride is added, the temperature is raised to 85°C and stirred for reaction for 3 hours, and then the dioxane is removed by rotary evaporation to obtain acetylated starch, wherein the amount ratio of cassava starch, acetic anhydride and dioxane is 50g:8mL:40mL.

[0055] Preparation of industrial sludge conditioner: Referring to Example 4, the starch derivative in the main agent is replaced with 30 wt% of acetylated starch and 2% of benzyltriethylammonium chloride, and the rest of the implementation process is exactly the same.

[0056] Comparative Example 2

[0057] This comparative example is the commercially available BliQ-9100 sludge conditioner.

[0058] The bottom sludge of a sewage station of a paper mill was taken, and the moisture content of the sample was 91.5%. The main agent prepared by Examples 1 to 4 and Comparative Example 1 and the sludge conditioner of Comparative Example 2 were added to the sludge at a dry weight of 5%, and stirred at 300 rpm for 5 minutes. Then, an auxiliary agent of 1% of the dry weight of the sludge was added, and the stirring was continued for 3 minutes. The sludge was allowed to stand for 30 minutes, and the sludge specific resistance and capillary water absorption time were tested. The sludge was then subjected to plate and frame filter pressing at a pressure of 0.5 MPa, and the moisture content of the mud cake after the filter pressing was tested. The specific test data are shown in the following table:

[0059] <![CDATA[Specific resistance of sludge / m·kg -1 > Capillary absorption time / s Mud cake moisture content / % Example 1 <![CDATA[3.3×10 11 ]]> 17.1 55.7 Example 2 <![CDATA[3.6×10 11 ]]> 15.9 58.3 Example 3 <![CDATA[3.1×10 11 ]]> 12.5 54.1 Example 4 <![CDATA[2.9×10 11 ]]> 13.8 52.7 Comparative Example 1 <![CDATA[1.7×10 12 ]]> 29.6 69.3 Comparative Example 2 <![CDATA[7.2×10 11 ]]> 21.4 61.8

[0060] From the test results in the above table, it can be seen that the sludge specific resistance after being treated with the sludge conditioner in the embodiment is 2.9-3.6×10 11 / kg, the capillary water absorption time is 12.5-17.1s. Compared with the control sludge, the dehydration property is significantly improved. The moisture content of the mud cake after conventional plate and frame filtration is less than 60%, which directly meets the backfilling requirements.

[0061] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0062] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. An industrial sludge conditioner, consisting of a main agent and an auxiliary agent, characterized in that: The main agent is composed of the following components: 28-35wt% starch derivative, 3.5-5.5wt% coagulant, 1.5-2wt% coagulant aid and 1-1.4wt% dispersant, the balance is water, and the auxiliary agent is hydrogen peroxide solution; The starch derivative is prepared by the following method: Step A1: Mix silane coupling agent KH550 and ethanol solution, add acetic acid to adjust the pH value to 3.5-4.5 and stir to hydrolyze for 1-1.3 hours, add starch and mix well, then neutralize with ammonia water, let stand for 24 hours, take the bottom precipitate and vacuum dry to obtain intermediate 1; Step A2: premix 1-chloropropanol, potassium carbonate and acetone, add intermediate 1 and mix well, introduce nitrogen protection, heat to 45-55°C, stir and reflux for 4-5h, and remove acetone by rotary evaporation after the reaction to obtain intermediate 2; Step A3: Intermediate 2, aluminum chloride and dioxane are mixed, nitrogen is introduced for protection, the temperature of a water bath is controlled at 50-60°C, acetic anhydride is slowly added with stirring for 1.5-2.2 hours, and dioxane is removed by rotary evaporation after the reaction to obtain a starch derivative.

2. An industrial sludge conditioner according to claim 1, characterized in that: The dosage ratio of starch, silane coupling agent KH550 and ethanol solution is 50g:1.5-2mL:55-70mL, and the volume fraction of the ethanol solution is 30%.

3. An industrial sludge conditioner according to claim 2, characterized in that: The usage ratio of intermediate 1, 1-chloropropanol, potassium carbonate and acetone is 50g:8-12mL:0.1-0.15g:60-80mL.

4. An industrial sludge conditioner according to claim 3, characterized in that: The usage ratio of intermediate 2, acetic anhydride, aluminum chloride and dioxane is 50g:2.2-2.8mL:15-20mg:40-50mL.

5. An industrial sludge conditioner according to claim 1, characterized in that: The coagulant is polyferric sulfate.

6. An industrial sludge conditioner according to claim 1, characterized in that: The coagulant is sodium silicate.

7. An industrial sludge conditioner according to claim 1, characterized in that: The dispersant is a polyether surfactant.

8. The production process of an industrial sludge conditioner according to any one of claims 1 to 7, characterized in that: The specific operation is: premix the coagulant, coagulant aid, dispersant and water, then add the starch derivative and mix well to form the main agent, and use the hydrogen peroxide solution as a single-component auxiliary agent.