CN112321134B

CN112321134B - Sludge dehydrating agent and application method thereof for reducing water content of sludge and recycling sludge

Info

Publication number: CN112321134B
Application number: CN202010716587.1A
Authority: CN
Inventors: 陈映竹
Original assignee: Changsha Jiannuo Environmental Technology Co ltd
Current assignee: Changsha Jiannuo Environmental Technology Co ltd
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2021-11-23
Anticipated expiration: 2040-07-23
Also published as: CN112321134A

Abstract

The invention belongs to the technical field of sludge treatment, and particularly relates to a sludge dehydrating agent which consists of lime and dry distillation residues; the dry distillation residue has a particle size of 30-500 μm, a hydrophobic angle of 91-97 DEG, and a specific surface area of 220-300 m²(ii) in terms of/g. The invention also provides a method for reducing the water content of the sludge and recycling the sludge based on the sludge dehydrating agent. The invention innovatively discovers that the carbonization residues with the particle size, the hydrophobic angle and the specific surface area and the lime have cooperativity in sludge dehydration, the specific resistance of the sludge can be synergistically reduced, the dehydration performance of the sludge can be effectively improved, and the heat value of the treated sludge can be improved, so that the treated sludge can be directly used as solid fuel, and high-value utilization is realized.

Description

Sludge dehydrating agent and application method thereof for reducing water content of sludge and recycling sludge

Technical Field

The invention belongs to the technical field of sludge treatment, and particularly relates to a dehydrating agent for sludge and a dehydrating treatment method.

Background

The town sludge is solid waste generated in the town domestic sewage treatment process, is rich in organic matters, and has a normal dry basis heat value of 1600-3600 kCal/kg. When the town sludge is used as an energy source, the town sludge has similarity with biomass in many aspects, high volatile component, low ignition temperature during combustion and better combustion performance. However, in China, the utilization rate of the sludge resource is less than 20%, and the problems are that the sludge dehydration performance is poor, the sludge moisture is high, the corresponding technical requirements of the sludge resource cannot be met, and the industrial implementation of the sludge resource utilization is hindered.

At present, the scale of the urban sewage treatment plant is different from tens of thousands of tons per day to tens of thousands of tons per day, and some of the urban sewage treatment plants are up to more than one million tons per day. The residual sludge is first gravity concentrated to water content of 96-98%, then treated with chemical conditioning, plate-frame filter pressing and heat drying to water content below 50%, finally mixed and burnt, brick-making, fertilizer application, landfill and other steps. The other system adopts centrifugal separation or belt filter pressing, and the water content is reduced to below 80 percent. Most of the town sludge with the water content of about 80 percent enters a sludge treatment disposal site for treatment. Before disposal, most of the waste water is re-diluted until the water content is 95% -98%, and after chemical agent conditioning or advanced oxidation treatment, the waste water is subjected to diaphragm filter pressing until the water content is about 50%. Obviously, when chemical agents such as 'ferric salt + lime' or 'PAC (polyaluminium chloride) + PAM (polyacrylamide)' are used for conditioning, the medicine consumption or medicine cost is high, most of the subsequent sludge incineration treatment is not effectively utilized, and the sludge cake after the sludge is dewatered by adding PAM conditioning has the adhesion phenomenon; when the high-grade oxidation such as a Fenton method (ferric salt and hydrogen peroxide) is adopted, the medicine consumption is very high, the equipment corrosion problem exists, and the like. Sometimes, there is even a problem that the press filtrate is difficult to handle.

In addition, products such as semi-coke, coal tar, coal gas and the like can be obtained in the low-temperature carbonization (the temperature is 650-700 ℃) co-production process of small-particle coal taking non-coking bituminous coal such as non-caking coal or weak caking coal and the like as raw materials. The application of the products is researched more, wherein, the technical report adopts semi coke obtained by dry distillation as a sludge dehydrating agent. For example, with respect to semi-coke powder conditioning municipal sludge [ see document 1: the semi-coke powder is used for conditioning municipal sludge and mechanism^[J]The journal of environmental engineering, 2017, 11(3): 1831-1836]And town sludge as fuel [ see document 2: preparation method of sludge biomass environment-friendly fuel in Limingda and forestry and land industry^[P].CN 109181807 A 2019.1.11]But the related reports in (1) are not industrialized. The research result of the document 1 shows that the semi-coke powder can obviously improve the filtering and dehydrating performance of the sludge, but the required adding amount is still larger and is 1.5-2.5 times of the dry sludge by mass. Document 2 discloses a method for preparing a sludge biomass fuel, but after the method is used for conditioning, filter-pressing and dehydrating the sludge, the water content of the sludge is still as high as about 55%, further flash evaporation and drying are needed, the process flow is long, the energy consumption is high, and air pollution and dust pollution exist. Moreover, in order to ensure the calorific value of the product as fuel, additional biomass is added in the subsequent processing. Because the biomass sources are dispersed, the collection, transportation and other expenses are high, the comprehensive cost is not low, and the selling price is at least 1000 yuan/ton (the selling price of the dry distillation residues is less than 300 yuan/ton) according to the current market quotation of China inland. Therefore, the production cost of the sludge biomass fuel is high.

In addition, in the low-temperature carbonization (temperature of 650-700 ℃) co-production process of small-particle coal using non-coking bituminous coal such as non-caking coal or weakly caking coal as a raw material, a carbonization residue is also produced in addition to products such as semi-coke, coal tar, coal gas and the like, and the amount of the carbonization residue accounts for 5-6% of that of the main product semi-coke. The residue has high ash content and low calorific value compared with semi coke (or semi coke powder), so that the application of the residue is limited, and the residue can be only used as low-grade fuel and is low-cost to treat. At present, less research is carried out on resource utilization of the carbonization residue after the semi-coke is separated by low-temperature carbonization of the small coal.

Disclosure of Invention

In order to solve the problems of limited dehydration effect, high cost, complex components, no toxic components, certain secondary pollution and the like of the conventional sludge dehydration means, the invention aims to provide a safe, effective and low-cost sludge dehydrating agent.

The second purpose of the invention is to provide a method for reducing the water content of sludge and realizing resource utilization, aiming at effectively reducing the water content of the sludge and realizing the treatment and resource utilization of industrial solid waste based on the novel cooperativity of the components of the sludge dehydrating agent.

A sludge dehydrating agent consists of lime and dry distillation residues;

the dry distillation residue has a particle size of 30-500 μm, a hydrophobic angle of 91-97 DEG, and a specific surface area of 220-300 m²/g。

The invention provides a closed dehydrating agent which is formed by the lime and the dry distillation residues in a binary way. The invention innovatively discovers that the carbonization residues with the particle size, the hydrophobic angle and the specific surface area and the lime have cooperativity in sludge dehydration, the specific resistance of the sludge can be synergistically reduced, the dehydration performance of the sludge can be effectively improved, and the heat value of the treated sludge can be increased, so that the treated sludge can be directly used as solid fuel, and high-value utilization is realized. The sludge dehydrating agent disclosed by the invention can effectively realize the treatment of the dry distillation residue solid waste and the sludge due to the synergy of the binary components, and can realize the resource utilization of the sludge, thereby really realizing the industrial effect of treating the waste.

In the invention, the dry distillation residue is a byproduct residue of dry distillation of non-coking small-particle bituminous coal at 650-700 ℃.

Preferably, the non-coking small particle bituminous coal is non-caking coal and/or weakly caking coal.

In the invention, the sludge dewatering agent is a mixture of the lime and the dry distillation residues or AB materials which exist independently before mixing. The AB material refers to lime and dry distillation residues which are not mixed before use (such as preparation and storage processes); only after being mixed in the using process, the mixture is added into the processing object, or the mixture is added into the processing object in sequence in any order and then mixed.

The invention also provides a method for reducing the water content of the sludge and recycling the sludge (namely an application method of the dehydrating agent), which is used for mixing the sludge to be dehydrated with the sludge dehydrating agent and then carrying out solid-liquid separation to obtain the dehydrated sludge.

The research of the invention finds that the synergy of lime and the dry distillation residues under the performance parameters can be benefited, the dehydration performance of the sludge can be unexpectedly improved under the condition of greatly simplifying the medicament types, and moreover, the sustainable and self-burning dehydrated sludge can be co-produced, so that the waste treatment by waste and the resource utilization are realized.

In the present invention, the water content of the sludge to be dewatered is not particularly limited, and the water content of the sludge to be treated is preferably controlled to be 95% to 98% in view of the sufficient mixing.

For example, if the water content of the original sludge is about 95% to 98%, the original sludge can be directly treated; if the water content is lower than 95% or even lower than 80%, the water can be selectively diluted; the dilution water may be process waste water or reclaimed water.

For example, the sludge to be dewatered is sludge obtained by performing gravity concentration treatment on town sludge, and the water content of the sludge is preferably 96-98%. Or the sludge to be dehydrated is sludge obtained by diluting sludge after centrifugal separation or belt filter pressing treatment.

Preferably, the dehydrated sludge and lime in the sludge dehydrating agent are mixed in advance, and the pH value of the system is controlled to be 8-10; subsequently, the dry distillation residue is added, mixed and subjected to solid-liquid separation.

Conventionally, the pH value of the sludge needs to be controlled to be more than 12 when the sludge is treated by lime, so that the obvious effect is achieved, and the treated sludge which can be independently used as fuel cannot be obtained at all. However, the present invention has innovatively found that, based on the synergy between the lime and the dry distillation residue, the water content of the sludge can be unexpectedly reduced significantly at the lower pH required by the present invention, and moreover, the treated sludge which can be directly used as a solid fuel can be also unexpectedly produced.

Preferably, the weight ratio of the dry distillation residue to the sludge to be treated is 0.3-0.8: 1 based on the dry weight of the sludge to be treated.

According to the technical scheme, based on the cooperation between the components of the dehydrating agent and the performance indexes of the components, the dehydrating effect can be improved unexpectedly on the premise of reducing the using amount and the types of medicaments, and the sludge which can be used as fuel can be directly co-produced unexpectedly, so that the waste treatment by waste and the high-value utilization of the waste are really realized. The method is a convenient and reliable method for reducing the water content of the sludge with high cost performance, low dosage and high efficiency; and the method has the advantages of low treatment cost, simple process flow and environmental friendliness.

In the invention, the dehydrating agent is mixed after being added, and preferably, the mixing time is 15-30 min.

And (3) carrying out solid-liquid separation on the sludge subjected to the mixing treatment of the dehydrating agent to obtain treated water and treated sludge. In the invention, the solid-liquid separation can adopt the technology known in the industry, and preferably adopts diaphragm filter pressing.

Preferably, the pressure of the membrane filter pressing process is less than 1.6MPa and less than 2.0 MPa.

The invention relates to a preferable treatment method, which comprises the steps of adding a proper amount of press filtrate or reclaimed water into town sludge with the water content of about 80%, crushing and diluting until the water content of the sludge is 95-98%, or directly adopting the sludge after gravity concentration of a town sewage treatment plant (usually, the water content is 96-98%), firstly adopting lime to adjust the pH value of the sludge to 8-10, and then adopting W as the weight_{Dry distillation residue}：W_{Dry sludge}0.3-0.8: 1.0, adding non-sticky coal or weakly sticky coal, performing dry distillation at 650-700 ℃, processing into dry distillation residues with the particle size of 30-500 mu m, reacting for 15-30 min under stirring, and pumping to a squeezing pressure<And (3) carrying out diaphragm filter pressing on a high-pressure diaphragm filter press with the pressure of 2.0 MPa. And finally, the filtered water is partially used for conditioning and diluting the sludge, and the surplus filtered water is returned to a sewage treatment plant for treatment. The obtained sludge filter cake is crushedThen directly becomes sludge fuel, and the technical indexes are as follows: the water content Mt is less than or equal to 40%, the heat value Qad, net is not less than 2400kCal/kg, the ash content Aad is not less than 36%, the volatile component Vad is not less than 30%, the sulfur content St, ad is not less than 0.4%, the pH is 8-10, and the requirement of continuous autonomous combustion can be met. The sludge fuel can be applied to boiler combustion power generation, and can also be applied to occasions such as power plants, cement plants, biomass power plant boiler mixed combustion and the like.

Advantageous effects

(1) The invention innovatively discovers that the physical and chemical interaction of the dry distillation residues and the lime with the performance indexes can be utilized to achieve a synergistic effect

According to the invention, based on the respective characteristics of the dry distillation residues and the lime-conditioned sludge and the synergistic effect between the dry distillation residues and the lime-conditioned sludge, the efficient dehydration and the improvement of the heat value can be realized on the premise of lower medicament dosage and component omission, and the high-cost-performance resource utilization of treating wastes with processes of wastes against one another is realized.

(2) High utilization rate of sludge resource, environment-friendly property, simple process flow and low production cost, thereby being beneficial to industrialized application

The invention innovatively discovers that lime and the dry distillation residues have synergistic effect in the aspects of reducing the water content of the sludge and improving the heat value of the treated sludge, and realizes the self-sustaining combustion of the treated sludge on the premise of reducing the dosage and reducing the types of medicaments.

Researches show that the sludge fuel treated by the method meets the requirement of continuous autonomous combustion due to the fact that the water content Mt is less than or equal to 40%, the heat value Qad and the net are less than or equal to 2400kCal/kg, and the sludge fuel can be applied to incineration power generation, cement plants, biomass power plant boilers, waste incineration power plants and the like. Therefore, the utilization rate of the sludge resource is high and the method is relatively environment-friendly.

Moreover, the dry distillation residues are industrial waste materials, and the lime source is wide. The technical scheme of the invention realizes the utilization of the waste materials, realizes the treatment of the waste with the waste, and realizes the resource utilization of the waste materials.

The whole process production process of the invention hardly causes new environmental pollution, and the production process of the sludge fuel of the invention does not need drying and other processes, and has simple process flow and lower energy consumption. The adopted dry distillation residues and lime are wide in source, low in cost and easy to obtain, particularly the lime can be obtained from local materials, and the required adding dosage is low. Therefore, the comprehensive production cost is low, thereby being beneficial to industrial application.

Drawings

FIG. 1 is a schematic flow chart of examples 1 to 4;

FIG. 2 is a schematic flow chart of example 5.

Detailed Description

In the following examples, unless otherwise stated, the by-products of the dry distillation residue system of non-sticky coal or weakly sticky coal in the course of dry distillation at 650-700 ℃ come from a certain production site in northwest, and after proper processing, the relevant indexes are measured as follows: 30-500 mu m of grain diameter, 12-15% of ash, 9-11% of volatile component and sulfur content<1.0 percent and the calorific value of about 5300 kCal/kg. The hydrophobic angle is 91-97 DEG, and the specific surface area is 220-300 m²/g。

And (3) synergistic effect experiment:

specific resistance of 1.81X 10¹³For example, when the carbonized residue or lime is added separately, the specific resistance of the sludge is reduced along with the increase of the dosage. When pressing W respectively_{Dry distillation residue}：W_{Dry sludge}＝0.3：1.0、W_{Dry distillation residue}：W_{Dry sludge}＝0.8：1.0、W_{Dry distillation residue}：W_{Dry sludge}1.0: 1.0 and W_{Dry distillation residue}：W_{Dry sludge}2.0: when the mass ratio of 1.0 is compared with that of the dry distillation residues which are added independently, the specific resistance of the sludge is respectively reduced to 8.51 multiplied by 10¹²m/kg、3.92×10¹²m/kg、2.78×10¹²m/kg and 4.93X 10¹¹m/kg; when pressing W respectively_Lime：W_{Dry sludge}＝0.03：1.0(pH 8)、W_Lime：W_{Dry sludge}＝0.08：1.0(pH 10)、W_Lime：W_{Dry sludge}0.15: 1.0(pH 12) and W_Lime：W_{Dry sludge}0.5: 1.0(pH ≧ 14) mass ratio, the sludge specific resistance was reduced to 1.43X 10 respectively¹³m/kg、1.10×10¹³m/kg、6.43×10¹²m/kg and 3.02X 10¹²m/kg。

When the two are added simultaneously, if a small amount of lime is adopted to adjust the pH value of the sludge to be 8-10 (the lime consumption is only about 3-8% of the dry sludge mass), and then the W is added_{Dry distillation residue}：W_{Dry sludge}0.3: the specific resistance of the sludge is respectively and rapidly reduced to 9.71 multiplied by 10 by adding the dry distillation residues according to the mass ratio of 1.0¹¹m/kg(pH8)～6.80×10¹¹m/kg (pH 10); when a small amount of lime is adopted to adjust the pH value of the sludge to be 8-10, and W is controlled_{Dry distillation residue}：W_{Dry sludge}0.8: the specific resistance of the sludge is respectively and rapidly reduced to 1.49 multiplied by 10 by adding the dry distillation residues according to the mass ratio of 1.0¹¹m/kg(pH8)～1.07×10¹¹m/kg (pH10), the specific resistance of the sludge required by sludge dehydration is less than or equal to 1.0 multiplied by 10¹²～4.0×10¹²Target of m/kg. This is much lower than when either the dry distillation residue or lime is added separately. As can be seen, the dry distillation residues and the lime are mixed according to a certain proportion (pH 8-10, W)_{Dry distillation residue}：W_{Dry sludge}0.3-0.8: 1.0) the effect of reducing the specific resistance of the sludge is far greater than that of the dry distillation residue or lime when the dry distillation residue or the lime is added separately, and the effect of '1 + 1' is obviously shown>2' of synergistic effect. Therefore, when the sludge is conditioned, the carbonization residue and the lime have obvious synergistic effect.

Meanwhile, a comparative experiment of semi coke powder replacing the dry distillation residue is also carried out. Firstly, adjusting the pH value of the sludge to 8-10 (the lime consumption is about 3% -8% of the dry sludge mass) by adopting a small amount of lime, and then respectively adjusting the pH value to W_{Semi coke powder}：W_{Dry sludge}0.3: 1.0 and W_{Semi coke powder}：W_{Dry sludge}0.8: 1.0, and adding the semi-coke powder which is described in the literature 1 and processed into the same particle size range as the dry distillation residues, the sludge specific resistance is respectively reduced to 5.76 multiplied by 10¹²m/kg(pH8，W_{Semi coke powder}：W_{Dry sludge}＝0.3：1.0)～4.51×10¹²m/kg(pH10，W_{Semi coke powder}：W_{Dry sludge}0.3: 1.0) and 1.93X 10¹²m/kg(pH8，W_{Semi coke powder}：W_{Dry sludge}＝0.8：1.0)～1.17×10¹²m/kg(pH10，W_{Semi coke powder}：W_{Dry sludge}＝0.8：1.0). Therefore, compared with the target product of dry distillation, the residue of the small-particle coal low-temperature dry distillation byproduct has better cooperativity with calcium oxide.

In addition, experiments also show that in the formula of the dry distillation residue plus lime, if other substances such as lignosulfonate or (and) carboxymethyl cellulose and the like are added, the synergistic effect between the substances disappears completely. Even if lime and the dry distillation residue are added according to the optimal proportion which can generate obvious synergistic effect.

Example 1

The sludge comes from a certain sludge treatment site of the Changsha in Hunan, and the water content is 78.6 percent. Adding appropriate amount of neutral water, stirring, diluting to obtain 50kg of sludge with water content of 96%, adjusting pH to 8 with lime, and adding water according to W_{Dry distillation residue}：W_{Dry sludge}0.8: 1.0, adding 1.60kg of dry distillation residue which is obtained by dry distillation of non-sticky coal at 650-700 ℃ and is processed into particles with the particle size of 30-500 mu m, reacting for 30min under stirring, and pumping to the area of 0.5m²And carrying out diaphragm filter pressing on a XAYG0.5/630-U type high-pressure diaphragm filter press with the pressing pressure of 1.6 MPa. Finally, 5.42kg of sludge filter cake is obtained, and the technical indexes are as follows: the water Mt is 37.20 percent, the heat value Qad and net are 3115kCal/kg, the ash content Aad is 31.62 percent, the volatile component Vad is 31.01 percent, the sulfur content St and ad are 0.30 percent, the pH value is 8, and the requirement of continuous autonomous combustion can be met.

Example 2

The sludge comes from the sludge treatment center in Hunan Tan City, and the water content is 77.5 percent. Adding appropriate amount of the press filtrate of the previous test, mincing, diluting to obtain 55kg of sludge with water content of 95%, adjusting pH of the sludge with lime 10, and adding water according to W_{Dry distillation residue}：W_{Dry sludge}0.3: 1.0, adding 0.83kg of dry distillation residue which is obtained by dry distillation of weak sticky coal at 650-700 ℃ and processed into particles with the particle size of 30-500 mu m, reacting for 15min under stirring, and pumping to an area of 0.5m²And carrying out diaphragm filter pressing on a XAYG0.5/630-U type high-pressure diaphragm filter press with the pressing pressure of 1.9 MPa. Finally, 5.31kg of sludge filter cake is obtained, and the technical indexes are as follows: moisture Mt of 36.11%, heat value Qad, net of 2406kCal/kg, ash content Aad of 34.51%, volatile matterThe distribution Vad is 31.16 percent, the sulfur content St and the ad are 0.15 percent, and the pH value 10 can meet the requirement of continuous autonomous combustion.

Example 3

The sludge comes from a sludge treatment site in Henan, and the water content is 79.2 percent. Adding appropriate amount of the press filtrate of the previous test, mincing, diluting to obtain 100kg of sludge with water content of 98%, adjusting pH to 9 with lime, and adding water according to W_{Dry distillation residue}：W_{Dry sludge}0.8: 1.0, adding 1.60kg of dry distillation residue which is obtained by dry distillation of non-sticky coal at 650-700 ℃ and is processed into particles with the particle size of 30-500 mu m, reacting for 30min under stirring, and pumping to the area of 0.5m²And carrying out diaphragm filter pressing on a XAYG0.5/630-U type high-pressure diaphragm filter press with the pressing pressure of 1.7 MPa. Finally, 5.60kg of sludge filter cake is obtained, and the technical indexes are as follows: the water Mt is 39.30%, the heat value Qad, net is 3788kCal/kg, the ash content Aad is 20.36%, the volatile component Vad is 36.85%, the sulfur content St, ad is 0.32%, and the pH is 9, so that the requirement of continuous autonomous combustion can be met.

Example 4

The sludge comes from a sludge treatment and disposal site in Guangdong and has water content of 77.1 percent. Adding appropriate amount of press filtrate from earlier stage test, mincing, diluting to obtain sludge with water content of 97% of 80kg, adjusting pH to 8 with lime, and adding water_{Dry distillation residue}：W_{Dry sludge}0.5: 1.0, adding 1.20kg of dry distillation residue which is obtained by dry distillation of non-sticky coal at 650-700 ℃ and is processed into particles with the particle size of 30-500 mu m, reacting for 20min under stirring, and pumping to the area of 0.5m²And carrying out diaphragm filter pressing on a XAYG0.5/630-U type high-pressure diaphragm filter press with the pressing pressure of 1.9 MPa. Finally, 5.16kg of sludge filter cake is obtained, and the technical indexes are as follows: the water content Mt is 34.13%, the heat value Qad and net are 2481kCal/kg, the ash content Aad is 35.40%, the volatile component Vad is 30.30%, the sulfur content St and ad are 0.23%, the pH value is 8, and the requirement of continuous autonomous combustion can be met.

Example 5

The water content of the sludge is 97.5 percent after the sludge is gravity-concentrated by a sewage treatment plant in a certain town of Hunan Otsuma, the sludge is weighed as 90kg, the pH value of the sludge is adjusted to 10 by lime, and the water content is adjusted according to W_{Dry distillation residue}：W_{Dry sludge}0.6: 1.0, adding 1.35kg of dry distillation residue which is obtained by dry distillation of weakly caking coal at 650-700 ℃ and is processed into particles with the particle size of 30-500 mu m, reacting for 25min under stirring, and pumping to the area of 0.5m²And carrying out diaphragm filter pressing on a XAYG0.5/630-U type high-pressure diaphragm filter press with the pressing pressure of 1.8 MPa. Finally, 5.25kg of sludge filter cake is obtained, and the technical indexes are as follows: the water Mt is 35.20%, the heat value Qad and net are 2856kCal/kg, the ash content Aad is 31.08%, the volatile component Vad is 32.65%, the sulfur content St and ad are 0.25%, the pH value is 10, and the requirement of continuous autonomous combustion can be met.

Claims

1. A method for reducing the water content of sludge and recycling the sludge is characterized in that sludge to be dehydrated and a sludge dehydrating agent composed of lime and dry distillation residues are mixed, wherein the dehydrated sludge and the lime in the sludge dehydrating agent are mixed in advance, and the pH value of a system is controlled to be 8-10; then adding the dry distillation residues, mixing and then carrying out solid-liquid separation to obtain dewatered sludge;

the weight ratio of the dry distillation residues to the sludge to be treated is 0.3-0.8: 1;

the dry distillation residue has a particle size of 30-500 μm, a hydrophobic angle of 91-97 DEG, and a specific surface area of 220-300 m²/g；

The dry distillation residues are byproduct residues of dry distillation of non-coking small-particle bituminous coal at 650-700 ℃;

the non-coking small-particle bituminous coal is non-sticky coal and/or weakly sticky coal.

2. The method for reducing the water content of the sludge and recycling the sludge as resources according to claim 1, wherein the water content of the sludge to be dehydrated is 95-98%.

3. The method for reducing the water content of the sludge and recycling the sludge as resources according to claim 2, wherein the sludge to be dewatered is sludge obtained by gravity concentration of town sludge, and the water content of the sludge is 96% -98%;

or the sludge to be dehydrated is sludge diluted after centrifugal separation or belt filter pressing treatment.

4. The method for reducing the water content of sludge and recycling as claimed in any one of claims 1 to 3, wherein the mixing time is 15 to 30 min.

5. The method for reducing the water content of the sludge and recycling the sludge as claimed in claim 1, wherein the solid-liquid separation is membrane filter pressing.

6. The method for reducing the water content of the sludge and recycling as resources according to claim 5, wherein the pressure of the diaphragm filter pressing process is more than or equal to 1.6MPa and less than 2.0 MPa.