CN115448554B - Method for preparing high-heat-value mud cake by using high-water-content organic sludge - Google Patents

Abstract

The invention belongs to the technical field of environmental protection and solid waste resource treatment, and discloses a method for preparing high calorific value mud cake using organic sludge with high moisture content. Under stirring conditions, a skeleton structuring agent, a flocculation modifier and a flocculant are added to the organic sludge in sequence for a mixing reaction; the skeleton structuring agent is composed of CaO, Ca(OH) ₂ , activated white mud and activated carbon; the flocculation modification The sludge agent is composed of polymerized ferric sulfate and polymerized aluminum sulfate; the flocculant is composed of quaternary ammonium salt and polyacrylamide; and then the treated mixed sludge is subjected to filter press dehydration and low-temperature drying to obtain a high calorific value mud cake. The present invention can significantly improve dehydration efficiency and low-temperature drying efficiency by designing the skeleton structure agent, flocculation modifier and flocculant components and combining them with specific processing sequences, and can significantly reduce heavy metal pollution in wastewater after filtering. The resulting mud cake has the advantages of low moisture content and high calorific value.

Description

A method for preparing high calorific value mud cake using organic sludge with high moisture content

Technical field

The invention belongs to the technical field of environmental protection and solid waste resource treatment, and specifically relates to a method for preparing high calorific value mud cake using organic sludge with high moisture content.

Background technique

Organic sludge comes from a wide range of sources, mainly produced by sewage treatment plants, biological fermentation plants, etc. Its main characteristics are high organic matter content, easy decay and odor, high moisture content, and most organic sludge has a colloidal structure, making dehydration difficult. In addition to a large amount of organic matter, organic sludge may also contain various pathogenic bacteria, parasite eggs, heavy metals, antibiotics, and various toxic and harmful substances that are difficult to degrade. If organic sludge is not properly disposed of, the various pollutants contained in it may cause greater harm to the surrounding environment.

Currently, commonly used organic sludge treatment methods include digestion, composting, incineration and dehydration. The digestion method uses the endogenous metabolism of trophic or anaerobic digestion bacteria to decompose part of the organic matter in the organic sludge to produce methane. This method can reduce the amount of sludge solids and produce usable energy such as methane. However, there are disadvantages such as large investment, long reaction time, and insignificant sludge reduction. The final digested sludge still has problems of difficulty in processing. Composting method refers to the process of using microorganisms to degrade a large amount of organic matter in sludge and turning it into an organic fertilizer with good stability. This method has a simple process and realizes the resource utilization of organic sludge. However, the heavy metals and other toxic and harmful substances contained in the original organic sludge must be within the scope of national standards. Therefore, the type of organic sludge processed by this method has great limitations. . Sludge incineration is the most thorough treatment method, which can greatly reduce the volume of sludge and completely decompose various toxic and harmful substances in the sludge. However, this method also consumes a lot of energy. When the sludge is not fully burned, it may also produce Dioxins and other secondary pollutants. The purpose of sludge dehydration is to remove capillary water and surface-attached water in sludge, thereby reducing its volume and weight. After dehydration, the sludge volume is reduced to 1/10 or even lower than the original volume, which is beneficial to transportation and subsequent processing. The dehydration method has a simple process, does not produce secondary pollutants, has low investment, and has obvious sludge reduction effect. It is a method with further development and application prospects.

The most commonly used sludge dewatering method is mechanical dehydration, but no matter which filter press is used for high moisture content sludge, it can only reduce the sludge moisture content to about 60%, and the moisture content is still very high. In recent years, the method of mechanical dehydration combined with external dehydration agents has been gradually developed. The external dehydration agent generally has a flocculation effect, which can cause the small molecular organic matter in the sludge to agglomerate into macromolecular substances and precipitate, thereby achieving efficient solid-liquid separation under certain conditions. The dehydration performance of conventional agents is weak and the dosage of the agent is large. Patent CN101693592A discloses a sludge dehydration aid. This method uses ferrous chloride as the main agent. It is simple to apply, but the dosage of the agent is large, and the ferric chloride used It accounts for 8-15% of the sludge weight. Patent CN108751667A discloses a conditioning agent for sludge dehydration and its application method. Although the dosage of this agent is small, its ingredients are complex. After dehydration, the moisture content of the sludge is still around 70%, and the effect of assisting dehydration is limited. Patent CN106746482A discloses a sludge dehydration composite conditioner and a sludge dehydration method. The sludge dehydration composite conditioner includes organic coagulants, inorganic coagulants, and auxiliaries. The organic coagulant is at least one of polydimethyldiallylammonium chloride, dimethyldiallylammonium chloride, acrylamide copolymer, and polyallylamine hydrochloride; The inorganic coagulant is at least one of aluminum salt and iron salt; the auxiliary agent is sodium dodecylbenzene sulfonate, linear alkylbenzene sodium sulfonate, TX-10 emulsifier, chitosan salt At least one of acid salt, chitosan quaternary ammonium salt, chitosan lactate, chitosan glutamate, and polyvinyl alcohol. This method can reduce the moisture content of the mud cake to about 60%, but the moisture content is still high, and the structural strength of the mud cake is low, and the filter press efficiency and subsequent low-temperature drying efficiency are not high. Most sludge dewatering conditioning agents ignore the role of the mechanical properties of the sludge. If the mechanical properties of the sludge are not good, the sludge will be "deformed" during filtration and dehydration, causing the capillary structure to shrink and affecting the dehydration effect. Therefore, the development of conditioning agents that can improve the mechanical properties of sludge has high application value.

Patent CN101985386A discloses a conditioning agent and conditioning method for domestic sludge dehydration. Under normal temperature and pressure conditions, polymerized aluminum sulfate, quicklime and bamboo charcoal are sequentially added to the sludge to be treated, and the polymer is added in sequence after stirring for at least 5 minutes. Acrylamide and quaternary ammonium salt, stir for at least 3 minutes, and finally press filter. The moisture content of the mud cake after treatment is 40 to 50%. Although this conditioner can reduce the moisture content of sludge to 40-50%, the structural strength of the mud cake is low and requires high filter press conditions. The filter cake is not easy to peel off from the filter medium, resulting in low filter press efficiency and Affects the efficiency of subsequent further low-temperature drying. In addition, the selection and addition order of conditioners in this conditioning process are unreasonable, resulting in the water after pressure filtration still containing various macromolecular organic pollutants and heavy metal ions, and there is still a large burden of subsequent sewage treatment.

Contents of the invention

In view of the shortcomings and shortcomings of the above existing technologies, the primary purpose of the present invention is to provide a method for preparing high calorific value mud cake using organic sludge with high moisture content.

Another object of the present invention is to provide a high-calorie mud cake prepared by the above method.

Another object of the present invention is to provide a method for preparing fuel using the above-mentioned high calorific value mud cake.

The object of the present invention is achieved through the following technical solutions:

A method for preparing high calorific value mud cake using organic sludge with high moisture content. The specific preparation steps are as follows:

(1) Under stirring conditions, add a framework structuring agent to the organic sludge and react for 5 to 30 minutes; the framework structuring agent consists of CaO, Ca(OH) ₂ , activated white mud and activated carbon;

(2) Add a flocculation modifier to the mixed material in step (1), and continue stirring and mixing for 5 to 30 minutes; the flocculation modifier consists of polymerized ferric sulfate and polymerized aluminum sulfate;

(3) Add flocculant to the reaction mixture in step (2), and continue stirring and mixing for 5 to 30 minutes; the flocculant consists of quaternary ammonium salt and polyacrylamide;

(4) Dehydrate the mixed sludge treated in step (3) through filter press to obtain dewatered sludge;

(5) Subject the dewatered sludge obtained in step (4) to low-temperature drying to obtain a high calorific value mud cake.

Further, the moisture content of the organic sludge described in step (1) is 30% to 99%.

Further, the mass percentage of each component in the framework structuring agent described in step (1) is: CaO 30% to 50%, Ca(OH) ₂ 30% to 40%, activated white mud 10% to 20% , activated carbon 10% to 20%.

Further preferably, the dosage of the framework structuring agent is 0.01-0.02kg/L sludge.

Further, the mass percentage of each component in the flocculation modifier described in step (2) is: 20% to 80% of polymerized iron sulfate and 20% to 80% of polymerized aluminum sulfate.

Further preferably, the dosage of the flocculation modifier is 0.01-0.02kg/L sludge.

Further, the mass percentage of each component in the flocculant described in step (3) is: quaternary ammonium salt 40% to 80%, polyacrylamide 20% to 60%.

Further preferably, the quaternary ammonium salt is selected from the group consisting of chitosan quaternary ammonium salt, polydimethyldiallylammonium chloride or polysiloxane quaternary ammonium salt. More preferred are polysiloxane quaternary ammonium salts. In the sludge dehydration process of the present invention, the use of polysiloxane quaternary ammonium salts has better performance in improving sludge dehydration than other quaternary ammonium salts.

Further preferably, the dosage of the flocculant is 0.01-0.02g/L sludge.

Further, a plate and frame filter press is used for the filter press dehydration described in step (4), and the dehydration pressure is 1 to 2 MPa.

Further, the low-temperature drying process in step (5) is performed until the moisture content is 15% to 25%.

A high-calorie mud cake is prepared by the above method. The calorific value of the high-calorie mud cake is 3000-4500kcal/kg.

A method for preparing fuel using the above-mentioned high calorific value mud cake, including the following steps:

The high calorific value mud cake is mixed evenly with the combustion accelerant potassium nitrate, catalyst manganese dioxide, desulfurizer calcium oxide and calorific value enhancer waste oil, and then compressed and molded to obtain fuel; the mass percentage of each raw material in the fuel is: High calorific value mud cake 50% to 70%, potassium nitrate 10% to 30%, manganese dioxide 3% to 5%, calcium oxide 1% to 7%, waste oil 10% to 20%.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention uses organic matter flocculation agents to promote the flocculation and precipitation of large amounts of sludge organic matter, improve the performance of dewatered sludge, and remove most organic matter in the water, which can quickly achieve sludge reduction and promote sludge dehydration. The addition of flocculation modifier allows the flocculant to interact more directly with organic macromolecular colloidal particles and dissolved organic matter with a changed structure, thereby achieving the effects of strengthening flocculation and sedimentation and accelerating filtration.

(2) The present invention uses skeleton agents to improve the mechanical stability of sludge, and at the same time, it can also fix heavy metals and other pollutants in the sludge, reduce its environmental migration ability, and provide prerequisites for the harmless disposal of sludge. Reduce the compressibility coefficient of sludge. Sludge with a high compressibility coefficient will deform the mud cake under the filtration pressure, causing the diameter of the capillary in between to shrink, making it difficult for water to pass through. By adding some framework materials to the sludge, the compression performance of the sludge can be improved. During the formation process of the mud cake, these substances serve as the skeleton of the mud cake to increase the structural strength of the mud cake, thereby making it easy for water to be removed from the mud cake, and at the same time, the filter cake is also easy to peel off from the filter medium.

(3) By designing the framework structure agent, flocculation modifier and flocculant components, and combining them with specific processing sequences, the present invention can significantly improve the dehydration efficiency and low-temperature drying efficiency, and significantly reduce heavy metals in the wastewater after filtering. Concentration of pollutants and organic pollutants, reducing the burden of subsequent sewage treatment.

(4) The method of the present invention has a remarkable solid-liquid separation effect, and the water after pressure filtration contains almost no macromolecular organic matter. Organic sludge with a moisture content higher than a certain value, especially organic waste such as bacterial residue, has a low zeta potential, a solid-liquid mixture that is in the form of colloid agglomeration, and very stable chemical properties. It is difficult to flocculate and dehydrate using general methods, which increases the cost of treatment. Extremely high. If the general flocculation and sedimentation method is used, the solid-liquid separation effect is not obvious. The wastewater after pressure filtration still contains various macromolecular organic pollutants, and the moisture content of the filter cake is still very high. The highly water-containing organic sludge treated by the method of the present invention after press filtration basically does not contain macromolecular organic matter, heavy metals, antibiotics and other dangerous pollutants. The TOC and COD values are greatly reduced, and the filter cake contains water. Low rate and high calorific value.

(5) The high calorific value mud cake obtained by the method of the present invention can be used to prepare high calorific value fuel, and has the advantages of low cost, sufficient combustion, and no secondary pollutants such as dioxins.

Detailed ways

The present invention will be described in further detail below with reference to examples, but the implementation of the present invention is not limited thereto.

Example 1

A method of preparing high calorific value mud cake using organic sludge with high moisture content in this embodiment includes the following preparation steps:

(1) Under stirring conditions, add a framework structuring agent to the organic sludge with a moisture content of 97% and react for 20 minutes; the framework structuring agent consists of 40% CaO, 30% Ca(OH) ₂ , 15% activated white It is composed of sludge and 15% activated carbon; the dosage of skeleton structural agent is 0.015kg/L sludge.

(2) Add a flocculation modifier to the mixed material in step (1), and continue stirring and mixing for 20 minutes; the flocculation modifier consists of 50% polymerized ferric sulfate and 50% polymerized aluminum sulfate; flocculation modification The dosage of agent is 0.015kg/L sludge.

(3) Add flocculant to the reaction mixture in step (2), and continue stirring and mixing for 20 minutes; the flocculant consists of 60% chitosan quaternary ammonium salt and 40% polyacrylamide; The dosage is 0.015g/L sludge.

(4) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (3) under a pressure of 1.6MPa (until no obvious free water comes out) to obtain dewatered sludge; measure the water content of the dewatered sludge The rate is 42%. The TOC value and COD value in the sewage after pressure filtration are 4.6 mg/L and 48 mg/L. The heavy metal content detection Cr, As, and Pb concentrations are all less than 0.5 ppm.

(5) Subject the dewatered sludge obtained in step (4) to low-temperature drying (65°C, 2 hours) to obtain a high calorific value mud cake with a moisture content of 20%. The caloric value of the mud cake was measured to be 3500kcal/kg.

The method for preparing fuel using the high calorific value mud cake of this embodiment has the following specific steps: in terms of mass percentage, 60% of the high calorific value mud cake obtained in step (5) is mixed with 20% of the combustion accelerant potassium nitrate and 4% of the catalyst dioxide. Add manganese, 4% desulfurizer calcium oxide and 12% calorific value enhancer waste oil to the mixer, stir and mix evenly, then put the evenly stirred mixture into the compressor, compress it into a cake shape, and obtain the above after molding fuel. The measured calorific value of the fuel is 3900kcal/kg.

The high calorific value mud cake obtained in this example and the prepared fuel were subjected to a combustion test. The results showed that the high calorific value mud cake was capable of self-sustaining combustion, but the combustion was incomplete and a large amount of smoke was produced. The detected dioxin concentration was 26.6ngTEQ/m ³ . The fuel obtained is fully burned, almost no smoke is produced, and no dioxin secondary pollutants are detected. It shows that the combustion performance of the mud cake can be significantly improved after the high calorific value mud cake obtained by the present invention is prepared into fuel with a combustion accelerant, catalyst manganese dioxide, desulfurizer calcium oxide and calorific value enhancer.

Example 2

A method of preparing high calorific value mud cake using organic sludge with high moisture content in this embodiment includes the following preparation steps:

(1) Under stirring conditions, add a framework structuring agent to the organic sludge with a moisture content of 97% and react for 10 minutes; the framework structuring agent consists of 30% CaO, 30% Ca(OH) ₂ , 20% activated white It is composed of sludge and 20% activated carbon; the dosage of skeleton structural agent is 0.02kg/L sludge.

(2) Add a flocculation modifier to the mixed material in step (1), and continue stirring and mixing for 10 minutes; the flocculation modifier consists of 80% polymerized ferric sulfate and 20% polymerized aluminum sulfate; flocculation modification The dosage of agent is 0.02kg/L sludge.

(3) Add flocculant to the reaction mixture in step (2), and continue stirring and mixing for 10 minutes; the flocculant consists of 80% chitosan quaternary ammonium salt and 20% polyacrylamide; The dosage is 0.02g/L sludge.

(4) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (3) under a pressure of 1.6MPa to obtain dewatered sludge; the moisture content of the dewatered sludge was measured to be 50%. The medium TOC value is 4.7mg/L, the COD value is 43mg/L, and the heavy metal content detection Cr, As, and Pb concentrations are all less than 0.5ppm.

(5) Subject the dewatered sludge obtained in step (4) to low-temperature drying (65°C, 2 hours) to obtain a high calorific value mud cake with a moisture content of 23%. The caloric value of the mud cake was measured to be 3200kcal/kg.

Example 3

A method of preparing high calorific value mud cake using organic sludge with high moisture content in this embodiment includes the following preparation steps:

(1) Under stirring conditions, add a framework structuring agent to the organic sludge with a moisture content of 97% and react for 30 minutes; the framework structuring agent consists of 40% CaO, 40% Ca(OH) ₂ , 10% activated white It is composed of sludge and 10% activated carbon; the dosage of skeleton structural agent is 0.01kg/L sludge.

(2) Add a flocculation modifier to the mixed material in step (1), and continue stirring and mixing for 30 minutes; the flocculation modifier consists of 20% polymerized ferric sulfate and 80% polymerized aluminum sulfate; flocculation modification The dosage of agent is 0.01kg/L sludge.

(3) Add flocculant to the reaction mixture in step (2), and continue stirring and mixing for 30 minutes; the flocculant consists of 40% chitosan quaternary ammonium salt and 60% polyacrylamide; The dosage is 0.01g/L sludge.

(4) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (3) under a pressure of 1.6MPa to obtain dewatered sludge; the moisture content of the dewatered sludge was measured to be 45%. The medium TOC value is 4.2mg/L, the COD value is 41mg/L, and the heavy metal content detection Cr, As, and Pb concentrations are all less than 0.5ppm.

(5) Subject the dewatered sludge obtained in step (4) to low-temperature drying (65°C, 2 hours) to obtain a high calorific value mud cake with a moisture content of 18%. The caloric value of the mud cake was measured to be 3800kcal/kg.

Example 4

Compared with Example 2, this embodiment uses polydimethyldiallylammonium chloride instead of chitosan quaternary ammonium salt as the quaternary ammonium salt component in the flocculant, and the rest are the same.

The moisture content of the dewatered sludge after treatment in this embodiment is 51%, the TOC value in the sewage after press filtering is 4.8 mg/L, the COD value is 50 mg/L, and the heavy metal content detection Cr, As, and Pb concentrations are all less than 0.5 ppm.

The dewatered sludge treated in this example was further subjected to low-temperature drying treatment (65°C, 2 h) to obtain dried sludge with a moisture content of 22%. The caloric value of the mud cake was measured to be 3400kcal/kg.

Example 5

Compared with Example 2, this embodiment uses polysiloxane quaternary ammonium salt-16 instead of chitosan quaternary ammonium salt as the quaternary ammonium salt component in the flocculant, and the rest are the same.

The moisture content of the dewatered sludge after treatment in this embodiment is 40%, the TOC value in the sewage after pressure filtration is 4.3 mg/L, the COD value is 39 mg/L, and the heavy metal content detection Cr, As, and Pb concentrations are all less than 0.5 ppm.

The dewatered sludge treated in this example was further subjected to low-temperature drying treatment (65°C, 1 h) to obtain dried sludge with a moisture content of 17%. The caloric value of the mud cake was measured to be 4100kcal/kg.

It can be seen from the results of Examples 1 to 5 that the polysiloxane quaternary ammonium salt used as the quaternary ammonium salt component in the flocculant of the present invention has better performance in improving sludge dehydration than other quaternary ammonium salts. The moisture content is further significantly reduced, and the subsequent low-temperature drying efficiency of dewatered sludge is more than doubled without significant reduction in the flocculation effect of organic matter. The reason may be that the low surface tension properties of polysiloxane in polysiloxane quaternary ammonium salts can reduce the interfacial tension between solid and liquid, allowing the water contained in the sludge floc grid to be released, thus benefiting the sewage treatment. The water in the mud is deeply removed, thereby improving the sludge dehydration efficiency and low-temperature drying efficiency. At the same time, due to the reduction of interfacial tension, the shear resistance and rheology of the sludge floc are reduced, making it easier for the conditioner components to mix and react with the sludge, and the utilization rate of the conditioner is significantly improved to achieve better dehydration effects.

Comparative example 1

Compared with Example 1, this comparative example does not add a framework structuring agent during the preparation process. The specific steps are as follows:

(1) Under stirring conditions, add a flocculation modifier to the organic sludge with a moisture content of 97%, and continue stirring and mixing for 30 minutes; the flocculation modifier consists of 50% polymerized ferric sulfate and 50% polymerized ferric sulfate. Composed of aluminum sulfate; the dosage of flocculation modifier is 0.015kg/L sludge.

(2) Add flocculant to the reaction mixture in step (1), and continue stirring and mixing for 30 minutes; the flocculant consists of 60% chitosan quaternary ammonium salt and 40% polyacrylamide; The dosage is 0.015g/L sludge.

(3) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (2) under a pressure of 1.6MPa (until no obvious free water comes out) to obtain dewatered sludge; measure the water content of the dewatered sludge The rate is 78%. The TOC value and COD value in the sewage after pressure filtration are 42 mg/L and 389 mg/L. The heavy metal content detection Cr, As, and Pb concentrations are 2.0 ppm, 1.3 ppm, and 1.7 ppm respectively.

(4) Subject the dewatered sludge obtained in step (3) to low-temperature drying (65°C, 2 h) to obtain a mud cake with a moisture content of 62%. The caloric value of the mud cake was measured to be 750kcal/kg.

It can be seen from the comparison between this comparative example and Example 1 that the skeleton structuring agent of the present invention serves as the skeleton of the mud cake to increase the structural strength of the mud cake, thereby making it easy to remove water from the mud cake, and the solid-liquid separation effect is significant. Low temperature drying efficiency is improved. The organic matter content of water after pressure filtration is significantly reduced, and the calorific value of the mud cake is significantly increased. It can also fix pollutants such as heavy metals in sludge to a certain extent and reduce its environmental migration ability.

Comparative example 2

Compared with Example 1, this comparative example does not add flocculation modifier during the preparation process. The specific steps are as follows:

(1) Under stirring conditions, add a framework structuring agent to the organic sludge with a moisture content of 97% and react for 30 minutes; the framework structuring agent consists of 40% CaO, 30% Ca(OH) ₂ , 15% activated white It is composed of sludge and 15% activated carbon; the dosage of skeleton structural agent is 0.015kg/L sludge.

(2) Add flocculant to the mixed material in step (1), and continue stirring and mixing for 30 minutes; the flocculant consists of 60% chitosan quaternary ammonium salt and 40% polyacrylamide; The dosage is 0.015g/L sludge.

(3) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (2) under a pressure of 1.6MPa (until no obvious free water comes out) to obtain dewatered sludge; measure the water content of the dewatered sludge The rate is 64%. The TOC value and COD value in the sewage after pressure filtration are 22 mg/L and 237 mg/L. The heavy metal content detection Cr, As, and Pb concentrations are 0.6 ppm, 0.8 ppm, and 1.1 ppm respectively.

(4) Subject the dewatered sludge obtained in step (3) to low-temperature drying (65°C, 2 h) to obtain a mud cake with a moisture content of 48%. The caloric value of the mud cake was measured to be 1700kcal/kg.

It can be seen from the comparison between this comparative example and Example 1 that the flocculation modifier of the present invention has the effects of strengthening flocculation sedimentation, reducing the content of organic matter in sewage after filter press, enhancing filtration and improving low-temperature drying efficiency, and significantly improves sludge drying efficiency. Pie caloric value.

Comparative example 3

Compared with Example 1, this comparative example does not add flocculant during the preparation process. The specific steps are as follows:

(1) Under stirring conditions, add a framework structuring agent to the organic sludge with a moisture content of 97% and react for 30 minutes; the framework structuring agent consists of 40% CaO, 30% Ca(OH) ₂ , 15% activated white It is composed of sludge and 15% activated carbon; the dosage of skeleton structural agent is 0.015kg/L sludge.

(2) Add a flocculation modifier to the mixed material in step (1), and continue stirring and mixing for 30 minutes; the flocculation modifier consists of 50% polymerized ferric sulfate and 50% polymerized aluminum sulfate; flocculation modification The dosage of agent is 0.015kg/L sludge.

(3) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (2) under a pressure of 1.6MPa (until no obvious free water comes out) to obtain dewatered sludge; measure the water content of the dewatered sludge The rate is 74%. The TOC value and COD value in the sewage after pressure filtration are 31 mg/L and 420 mg/L. The heavy metal content detection Cr, As, and Pb concentrations are 0.5 ppm, 0.7 ppm, and 0.8 ppm respectively.

(4) Subject the dewatered sludge obtained in step (3) to low-temperature drying (65°C, 2 h) to obtain a mud cake with a moisture content of 60%. The caloric value of the mud cake was measured to be 800kcal/kg.

It can be seen from the comparison between this comparative example and Example 1 that the flocculant of the present invention can improve the dehydration performance of sludge, promote the dehydration of sludge, can quickly reduce the amount of sludge, and remove most organic matter in the water. Significantly increase the caloric value of mud cake.

Comparative example 4

Compared with Example 1, the preparation process of this comparative example involves adding the framework structuring agent, flocculation modifier and flocculant to the reaction at one time. The specific steps are as follows:

(1) Under stirring conditions, add framework structuring agent, flocculation modifier and flocculant at one time to the organic sludge with a moisture content of 97% and mix and react for 60 minutes. The skeleton structural agent is composed of 40% CaO, 30% Ca(OH) ₂ , 15% activated white mud and 15% activated carbon. The dosage of the skeleton structural agent is 0.015kg/L sludge; the flocculation modifier It is composed of 50% polymerized ferric sulfate and 50% polymerized aluminum sulfate, and the dosage of flocculation modifier is 0.015kg/L sludge; the flocculant is composed of 60% chitosan quaternary ammonium salt and 40% polyethylene sulfate. Composed of acrylamide, the dosage of flocculant is 0.015g/L sludge.

(2) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (1) under a pressure of 1.6MPa to obtain dewatered sludge.

The moisture content of the dewatered sludge was measured to be 63%. The TOC value and COD value in the sewage after press filtering were 20 mg/L and 198 mg/L. The heavy metal content detected Cr, As, and Pb concentrations were 1.5 ppm, 1.1 ppm, and 1.4 ppm respectively. .

(3) Subject the dewatered sludge obtained in step (2) to low-temperature drying (65°C, 2 hours) to obtain a mud cake with a moisture content of 45%. The caloric value of the mud cake was measured to be 1500kcal/kg.

It can be seen from the comparison results between this comparative example and Example 1 that compared with the method of adding each conditioning agent at once, the present invention reacts by first adding the framework structuring agent, and then sequentially adding the flocculation modifier reaction and flocculant. The reaction can significantly improve the dehydration efficiency and low-temperature drying efficiency, significantly reduce the concentration of heavy metal pollutants and organic pollutants in the wastewater after filtering, and significantly increase the calorific value of the mud cake.

Comparative example 5

Compared with Example 1, the preparation process of this comparative example is that the framework structuring agent is first put in for reaction, and then the flocculation modifier and flocculant are put in one time for reaction. The specific steps are as follows:

(1) Under stirring conditions, add a framework structuring agent to the organic sludge with a moisture content of 97% and react for 20 minutes; the framework structuring agent consists of 40% CaO, 30% Ca(OH) ₂ , 15% activated white It is composed of sludge and 15% activated carbon; the dosage of skeleton structural agent is 0.015kg/L sludge.

(2) Add a flocculation modifier and a flocculant to the mixed material in step (1) at one time. The flocculation modifier consists of 50% polymerized ferric sulfate and 50% polymerized aluminum sulfate. The flocculation modifier The dosage of flocculant is 0.015kg/L sludge; the flocculant is composed of 60% chitosan quaternary ammonium salt and 40% polyacrylamide; the dosage of flocculant is 0.015g/L sludge; continue Stir and mix for 40 minutes.

(3) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (2) under a pressure of 1.6MPa (until no obvious free water comes out) to obtain dewatered sludge; measure the water content of the dewatered sludge The rate is 64%. The TOC value and COD value in the sewage after pressure filtration are 11 mg/L and 124 mg/L. The heavy metal content detection Cr, As, and Pb concentrations are 0.8 ppm, 0.7 ppm, and 0.9 ppm respectively.

(4) Subject the dewatered sludge obtained in step (3) to low-temperature drying (65°C, 2 h) to obtain a mud cake with a moisture content of 38%. The caloric value of the mud cake was measured to be 2200kcal/kg.

It can be seen from the comparison between this comparative example and Example 1 that adding the flocculation modifier and flocculant in batches for reaction can significantly improve the dehydration efficiency and low-temperature drying compared to adding the flocculation modifier and flocculant at one time for reaction. efficiency, and significantly reduce the concentration of heavy metal pollutants and organic pollutants in the wastewater after pressure filtration, and significantly increase the calorific value of the mud cake.

Comparative example 6

Compared with Example 1, the preparation process of this comparative example is to first add the framework structuring agent and the flocculation modifier to react at one time, and then add the flocculant to react. The specific steps are as follows:

(1) Under stirring conditions, add a framework structuring agent and a flocculation modifier to the organic sludge with a moisture content of 97% at one time for a mixing reaction of 40 minutes; the framework structuring agent consists of 40% CaO, 30% Ca(OH ) _2. It is composed of 15% activated white mud and 15% activated carbon. The dosage of skeleton structuring agent is 0.015kg/L sludge; the flocculation modifier is composed of 50% polymerized ferric sulfate and 50% polymerized aluminum sulfate. , the dosage of flocculation modifier is 0.015kg/L sludge.

(2) Add flocculant to the mixed material in step (1), and continue stirring and mixing for 20 minutes; the flocculant consists of 60% chitosan quaternary ammonium salt and 40% polyacrylamide; The dosage is 0.015g/L sludge.

(3) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (2) under a pressure of 1.6MPa (until no obvious free water comes out) to obtain dewatered sludge; measure the water content of the dewatered sludge The rate is 62%. The TOC value and COD value in the sewage after pressure filtration are 9 mg/L and 105 mg/L. The heavy metal content detection Cr, As, and Pb concentrations are 0.5 ppm, 0.6 ppm, and 1.0 ppm respectively.

(4) Subject the dewatered sludge obtained in step (3) to low-temperature drying (65°C, 2 h) to obtain a mud cake with a moisture content of 35%. The caloric value of the mud cake was measured to be 2600kcal/kg.

It can be seen from the comparison results between this comparative example and Example 1 that adding the framework structuring agent and the flocculation modifier in batches for reaction can significantly improve the dehydration efficiency and low temperature compared to adding the framework structuring agent and the flocculation modifier in one go. Drying efficiency, significantly reducing the concentration of heavy metal pollutants and organic pollutants in the wastewater after filtration, and significantly increasing the calorific value of the mud cake.

Comparative example 7

Compared with Example 1, the preparation process of this comparative example is to first add the framework structuring agent and the flocculant to react at one time, and then add the flocculation modifier to react. The specific steps are as follows:

(1) Under stirring conditions, add a skeleton structuring agent and a flocculant to the organic sludge with a moisture content of 97% at one time for a mixing reaction of 40 minutes; the skeleton structuring agent consists of 40% CaO, 30% Ca(OH) ₂ , 15% activated white mud and 15% activated carbon, the dosage of the skeleton structural agent is 0.015kg/L sludge; the flocculant is composed of 60% chitosan quaternary ammonium salt and 40% polyacrylamide, The dosage of flocculant is 0.015kg/L sludge.

(2) Add a flocculation modifier to the mixed material in step (1), and continue stirring and mixing for 20 minutes; the flocculation modifier consists of 50% polymerized ferric sulfate and 50% polymerized aluminum sulfate; flocculation modification The dosage of agent is 0.015g/L sludge.

(3) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (2) under a pressure of 1.6MPa (until no obvious free water comes out) to obtain dewatered sludge; measure the water content of the dewatered sludge The rate is 76%. The TOC value and COD value in the sewage after pressure filtration are 35 mg/L and 407 mg/L. The heavy metal content detection Cr, As, and Pb concentrations are 0.6 ppm, 0.8 ppm, and 1.1 ppm respectively.

(4) Subject the dewatered sludge obtained in step (3) to low-temperature drying (65°C, 2 h) to obtain a mud cake with a moisture content of 61%. The caloric value of the mud cake was measured to be 850kcal/kg.

It can be seen from the comparison results between this comparative example and Example 1 that compared with first adding the framework structuring agent and the flocculant to react at one time, and then adding the flocculation modifier to react, the present invention reacts by adding the framework structuring agent first, and then sequentially Adding flocculation modifier reaction and flocculant reaction can significantly improve dehydration efficiency and low-temperature drying efficiency, significantly reduce the concentration of heavy metal pollutants and organic pollutants in the wastewater after filter press, and significantly increase the calorific value of the mud cake.

Comparative example 8

Compared with Example 1, the preparation process of this comparative example is to first put in the flocculation modifier and the flocculant reaction at one time, and then put in the framework structuring agent to react. The specific steps are as follows:

(1) Under stirring conditions, add flocculation modifier and flocculant at one time to the organic sludge with a moisture content of 97% and stir and mix for 40 minutes; the flocculation modifier consists of 50% polymerized ferric sulfate and 50% % polymerized aluminum sulfate, the dosage of flocculation modifier is 0.015kg/L sludge; the flocculant is composed of 60% chitosan quaternary ammonium salt and 40% polyacrylamide; the dosage of flocculant The dosage is 0.015g/L sludge.

(2) Add a framework structuring agent to the mixed material in step (1) and react for 20 minutes; the framework structuring agent consists of 40% CaO, 30% Ca(OH) ₂ , 15% activated white mud and 15% activated carbon; The dosage of skeleton structural agent is 0.015kg/L sludge.

(3) Use a plate and frame filter press to filter and dehydrate the mixed sludge treated in step (2) under a pressure of 1.6MPa (until no obvious free water comes out) to obtain dewatered sludge; measure the water content of the dewatered sludge The rate is 72%. The TOC value and COD value in the sewage after pressure filtration are 28 mg/L and 327 mg/L. The heavy metal content detection Cr, As, and Pb concentrations are 1.1 ppm, 0.8 ppm, and 0.9 ppm respectively.

(4) Subject the dewatered sludge obtained in step (3) to low-temperature drying (65°C, 2 h) to obtain a mud cake with a moisture content of 54%. The caloric value of the mud cake was measured to be 1200kcal/kg.

It can be seen from the comparison results between this comparative example and Example 1 that the present invention reacts by first adding the framework structuring agent, and then sequentially adding the flocculation modifier and the flocculant to react. Compared with first adding the flocculation modifier and the flocculant, The method of reacting the flocculant and then adding the framework structuring agent can significantly improve the dehydration efficiency and low-temperature drying efficiency, significantly reduce the concentration of heavy metal pollutants and organic pollutants in the wastewater after filtering, and significantly increase the calorific value of the mud cake.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, etc. may be made without departing from the spirit and principles of the present invention. All simplifications should be equivalent substitutions, and are all included in the protection scope of the present invention.

Claims (6)

1. A method for preparing high calorific value mud cake using organic sludge with high moisture content, which is characterized in that the specific preparation steps are as follows: (1) Under stirring conditions, add a framework structuring agent to the organic sludge and react for 5 to 30 minutes; the framework structuring agent consists of CaO, Ca(OH) ₂ , activated white mud and activated carbon; (2) Add a flocculation modifier to the mixed material in step (1), and continue stirring and mixing for 5 to 30 minutes; the flocculation modifier consists of polymerized ferric sulfate and polymerized aluminum sulfate; (3) Add flocculant to the reaction mixture in step (2), and continue stirring and mixing for 5 to 30 minutes; the flocculant is composed of quaternary ammonium salt and polyacrylamide; (4) Dehydrate the mixed sludge treated in step (3) through press filtration to obtain dewatered sludge; (5) Subject the dewatered sludge obtained in step (4) to low-temperature drying to obtain a high calorific value mud cake; The mass percentage of each component in the framework structuring agent described in step (1) is: CaO 30%~50%, Ca(OH) ₂ 30%~40%, activated white mud 10%~20%, activated carbon 10% %~20%; the dosage of the framework structuring agent is 0.01~0.02kg/L sludge; The mass percentage of each component in the flocculation modifier described in step (2) is: polymerized ferric sulfate 20% to 80%, polymerized aluminum sulfate 20% to 80%; the dosage of the flocculation modifier is 0.01~0.02kg/L sludge; The mass percentage of each component in the flocculant described in step (3) is: 40% to 80% of quaternary ammonium salt, 20% to 60% of polyacrylamide, and the quaternary ammonium salt is polysiloxane quaternary ammonium Salt; the dosage of the flocculant is 0.01~0.02g/L sludge. 2. A method for preparing high calorific value mud cake using organic sludge with high moisture content according to claim 1, characterized in that the moisture content of the organic sludge in step (1) is 30% to 99%. 3. A method for preparing high calorific value mud cake using organic sludge with high moisture content according to claim 1, characterized in that the filter press dehydration in step (4) adopts a plate and frame filter press, and the dehydration pressure is 1~2MPa. 4. A method for preparing high calorific value mud cake using organic sludge with high moisture content according to claim 1, characterized in that the low-temperature drying process in step (5) is performed until the moisture content is 15%~25%. . 5. A high calorific value mud cake, characterized in that it is prepared by the method described in any one of claims 1 to 4, and the calorific value of the high calorific value mud cake is 3000 to 4500 kcal/kg. 6. A method for preparing fuel using the high calorific value mud cake according to claim 5, characterized in that it includes the following steps: The high calorific value mud cake is mixed evenly with the combustion accelerant potassium nitrate, catalyst manganese dioxide, desulfurizer calcium oxide and calorific value enhancer waste oil, and then compressed and molded to obtain fuel; the mass percentage of each raw material in the fuel is: High calorific value mud cake 50%~70%, potassium nitrate 10%~30%, manganese dioxide 3%~5%, calcium oxide 1%~7%, waste oil 10%~20%.