CN109467290B

CN109467290B - Grinding ball for sludge treatment equipment

Info

Publication number: CN109467290B
Application number: CN201811337438.3A
Authority: CN
Inventors: 彭代信; 苏艳丽
Original assignee: Suzhou Yiketai Electronic Material Co ltd
Current assignee: Suzhou Yiketai Electronic Material Co ltd
Priority date: 2016-11-03
Filing date: 2016-11-03
Publication date: 2021-07-16
Anticipated expiration: 2036-11-03
Also published as: CN106396310A; CN109467290A; CN106396310B

Abstract

The invention discloses a grinding ball for sludge treatment equipment. The grinding ball for the sludge treatment equipment is used for sludge treatment, the wall of the sludge cell is broken through a freezing method, the colloid structure in the sludge is destroyed, and the breaking requirement of the sludge cell for releasing the gap water in the sludge cell is met, so that the dehydration performance of the sludge is improved, and the defect that the existing dehydration process can only remove free water and part of the gap water is overcome.

Description

Grinding ball for sludge treatment equipment

The invention belongs to divisional application with the name of sludge treatment equipment, application date of 2016, 11 and 3 and application number of 2016109913599, and belongs to the technical part of components.

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a grinding ball for sludge treatment equipment.

Background

The sludge is solid waste generated in the sewage treatment process, the total treatment water amount and the treatment degree of a sewage plant are continuously enlarged and improved along with the development of the domestic sewage treatment industry, the generated sludge amount is increased day by day, the treatment investment and the operation cost of the sludge are huge, the cost for sludge treatment accounts for 20 to 50 percent of the operation cost of the sewage treatment plant, and heavy burden is brought to the sewage treatment plant. The sewage sludge contains a large amount of organic matters, nutrient substances such as nitrogen, phosphorus and the like, and toxic and harmful components such as heavy metals, pathogenic bacteria, parasites and the like. In order to prevent secondary pollution caused by sludge and ensure normal operation and treatment effect of sewage treatment plants, the positions occupied by sewage and sludge treatment in sewage treatment in China are increasingly prominent. After the sludge of the municipal sewage plant is concentrated and dehydrated, the water content of the sludge is about 80 percent, and the dehydrated sludge can be subjected to sanitary landfill, fermentation fertilizer preparation and drying treatment. The direct landfill treatment of the sludge can affect the normal operation of a landfill site, occupies a large area of the landfill site, and is forbidden at present. Because the content of heavy metal in sludge in China exceeds the standard, if the sludge is composted in agriculture, the value of crops is affected, and the market acceptance degree is low. The sludge drying technology generally adopts steam as a heat source, and adopts heat exchange, so that the energy consumption is high and the operation cost is high; and high temperature drying also presents a dust explosion risk. Sludge thermal hydrolysis wall breaking is adopted, a high-temperature heat source is needed to heat the sludge, and the energy consumption is high; and the high-temperature heat source has potential safety hazard in actual production.

In the prior art, the high water content of the sludge is a key problem for restricting the sludge treatment and utilization, and the biological sludge contains water in different states, including free water, interstitial water, adsorbed water and surface bound water. The traditional dehydration process can only remove free water and partial interstitial water, and the removal rate of sludge intercellular interstitial water is very low. Therefore, it is necessary to develop new means for effectively increasing the sludge dewatering rate, and it is also necessary to reduce the resource consumption and the environmental pollution as the sludge treatment process.

Disclosure of Invention

The invention aims to provide a sludge treatment method, which can effectively improve the dehydration performance of sludge and is beneficial to sludge treatment and cost reduction.

In order to achieve the purpose, the invention adopts the technical scheme that:

a sludge treatment device, cooperating with the above sludge treatment method, comprises a sludge cooler, a freezer, a ball mill, a conveying screw, a centrifuge and a refrigerator which are communicated in sequence; the sludge cooling machine is provided with a cooling fluid inlet and a cooling fluid outlet; the refrigerator is provided with a freezing gas inlet and a freezing gas outlet; the ball mill is provided with a cooling gas inlet and a cooling gas outlet; the conveying screw is provided with a heating fluid inlet and a heating fluid outlet; the centrifuge is provided with a clear liquid outlet; the refrigerator is provided with an air inlet and an air outlet; a cooling fluid inlet of the sludge cooler is communicated with a heating fluid outlet of the conveying screw, and a cooling fluid outlet of the sludge cooler is communicated with a heating fluid inlet of the conveying screw; the air inlet of the refrigerator is communicated with the freezing gas outlet of the refrigerator and the cooling gas outlet of the ball mill, and the air outlet of the refrigerator is communicated with the freezing gas inlet of the refrigerator and the cooling gas inlet of the ball mill; grinding balls are arranged in the ball mill; the grinding ball comprises a ceramic body and an inert polymer layer coated on the outer surface of the ceramic body; the thickness of the inert polymer layer is 0.2-0.3 microns.

The sludge treatment equipment also comprises a sludge pump, and the sludge with the water content of 80 percent is conveyed to the sludge cooler through the sludge pump. The sludge cooler, the refrigerator, the ball mill, the conveying screw and the centrifuge are all provided with sludge inlets and outlets which are connected in sequence to form a sludge conveying path. Grinding balls are arranged in the ball mill, and silicon dioxide, boron oxide, yttrium oxide, magnesium oxide and boron oxide are mixed to prepare mixed powder; smelting the mixed powder at 1500 ℃ for 1 hour, and quenching to obtain a block; crushing the block, and sieving the crushed block through a 325-mesh standard sieve to obtain ceramic powder; then adding lime into the ceramic powder, mixing and pressing the mixture into balls; finally sintering for half an hour at 950 ℃ and then sintering for 1 hour at 1200 ℃ to obtain a ceramic body; adding butyl acrylate, N-hydroxymethyl acrylamide, styrene and isomeric tridecanol polyoxyethylene ether into water to prepare emulsion; and then dropwise adding a potassium persulfate aqueous solution, and reacting at 70-75 ℃ for 1.5-2 hours to obtain the inert polymer slurry. Dispersing the ceramic body in ethanol, and then adding slurry of an inert polymer; mixing for 2 hours, and then adding maleic anhydride and diethyl phosphite; mixing for 2 hours; and then removing the solvent, and treating at 120-135 ℃ for 20 minutes to coat an inert polymer layer on the outer surface of the ceramic body, thus obtaining the grinding ball.

In the invention, the sludge cooler is a paddle cooler; the freezer is a belt freezer. The sludge cooling machine adopts paddle type cooling equipment to cool down the sludge in an indirect heat exchange mode, and in the belt type refrigerating machine, low-temperature cooling gas enters the refrigerating machine from the bottom and is in direct contact with the sludge, so that the temperature of the sludge is reduced. The sludge temperature is further reduced along with the conveying of the sludge on the belt; preferably, a freezing gas inlet is arranged at the bottom of the refrigerator; the refrigerator still is equipped with temperature sensing probe, prevents that freezing broken wall key parameter from going out the problem, effectively monitors the temperature of freezing mud, guarantees freezing dewatering quality.

The equipment is used for sludge treatment and comprises the following steps: conveying the sludge to be treated to a cooler; then adjusting the temperature of the sludge to 5-10 ℃; then sending the sludge into a refrigerator, and adjusting the temperature of the sludge to-10 to-5 ℃; then sending the frozen sludge into a ball mill, cooling the sludge in the gas, and ball-milling the sludge by using the ball mill; conveying the ball-milled sludge to a centrifuge by using a conveying screw, centrifuging, and removing clear liquid to finish freezing wall breaking and dewatering of the sludge; the surface temperature of the conveying screw is 15-20 ℃; the grinding ball comprises a ceramic body and an inert polymer layer coated on the outer surface of the ceramic body.

The freezing method breaks the sludge cell wall, destroys the colloid structure in the sludge, changes the distribution condition of water in the sludge, meets the requirement of the release of the gap water in the sludge cells for the breaking of the sludge cells, thereby improving the dehydration performance of the sludge, wherein the freezing ball milling is the key, the ball milling effect is directly related to the treatment effect of the sludge and water molecules, the selection of the grinding balls has very high influence on the ball milling quality except the temperature, the existing grinding balls are generally used for grinding inorganic materials with strong rigidity, and are not suitable for the sludge material; the ceramic sintered body is used as the main structure of the grinding ball, so that the grinding ball has an excellent grinding effect on sludge, and the defect that the existing grinding ball is too high in hardness and not beneficial to toughness sludge grinding is overcome; particularly, the outer surface of the grinding ball is coated with a layer of inert polymer, and compared with sludge, the inertia of the inert polymer overcomes the problem that the sludge is adhered to the outer surface of the grinding ball, and the ball milling effect is improved; meanwhile, the ceramic body is compatible with different inorganic components, and a stepped sintering process is adopted, so that the problem that the existing ceramic sintered body has gaps is solved, and when the ceramic body is coated by a polymer, an emulsion polymerization product is good in compatibility with the ceramic body under the coordination of small molecules and high in adhesive force, and is tightly attached to the ceramic body after being cured; particularly, the thickness of the inert polymer layer arranged on the outer side of the ceramic body is 0.2-0.3 micrometer, so that the performance of the ceramic body is not influenced, and the function of the inert polymer can be realized.

In the invention, after the sludge of the municipal sewage plant is concentrated and dehydrated, the water content of the sludge is about 80 percent, so the water content of the sludge to be treated is generally 80 percent.

In the invention, the sludge temperature is adjusted to 5-10 ℃ by adopting an indirect heat exchange mode; the sludge temperature is adjusted to-10 to-5 ℃ by adopting a direct air cooling mode. Thereby the mud cooling is slowly even, freezes fast, can reduce defect such as inside micelle and produce, provides good basis for follow-up freezing broken wall. The temperature of the cooling gas is-20 to-15 ℃. The ball mill is internally pumped with cooling gas, the low-temperature environment in the ball mill is maintained, the wall breaking effect is further increased, and the uniformity of the ball milling effect is also ensured.

In the invention, the rotation speed is 2800-3500 rpm during centrifugal separation; the centrifugal separation time is 2-3 minutes. Can effectively separate solid from liquid obtained by breaking the wall.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

1. the invention discloses sludge freezing wall-breaking treatment equipment for the first time, which breaks the sludge cell wall through a freezing method, destroys the colloid structure in the sludge, changes the distribution condition of water in the sludge, and meets the requirement of the release of gap water in the sludge cells on the breaking of the sludge cells, thereby improving the dehydration performance of the sludge and solving the defect that the existing dehydration process can only remove free water and part of the gap water.

2. The device of the invention cools the sludge by adopting an indirect heat exchange mode, so that the sludge is cooled slowly and uniformly, and the generation of internal colloidal particles is avoided; the way that the freezing gas directly contacts the sludge is adopted, the moisture in the sludge which is uniformly cooled is changed into solid from liquid, and the microbial structure of the sludge is destroyed; solid sludge is crushed by a ball mill, the physical and biological structures of the sludge are further destroyed, and the wall breaking effect is better; the water content of the sludge is reduced from 80% to 40%, and an unexpected effect is achieved.

3. The sludge treatment equipment disclosed by the invention is reasonable in composition and compact in structure, the cooling medium comprising cooling gas and cooling fluid can be recycled, and particularly the cooling fluid can be recycled between the cooler and the conveying screw, so that the waste of energy and materials is greatly reduced, and the problem of secondary pollution to the environment is solved.

4. The grinding ball disclosed by the invention can effectively grind the sludge, avoids being bonded with the sludge under the action of the outer polymer layer, and provides a good foundation for breaking the wall and yielding water.

5. The equipment provided by the invention has small odor generation amount when used for treating sludge, and realizes low-temperature dewatering of the sludge by perfect process steps and reasonable treatment equipment; the defect of a high-temperature heat source in the prior art is avoided, the method is safe, the cost is greatly saved, the pollution to the environment can be reduced, and the method is more suitable for industrial production.

Drawings

FIG. 1 is a schematic view of a sludge treatment apparatus;

the device comprises a sludge cooler 1, a refrigerator 2, a ball mill 3, a conveying screw 4, a centrifuge 5, a refrigerator 6, a sludge pump 7 and a clear liquid outlet 8.

Detailed Description

The invention is further described with reference to the following figures and examples:

preparing a grinding ball: mixing silicon dioxide, boron oxide, yttrium oxide, magnesium oxide and boron oxide to prepare mixed powder; smelting the mixed powder at 1500 ℃ for 1 hour, and quenching to obtain a block; crushing the block, and sieving the crushed block through a 325-mesh standard sieve to obtain ceramic powder; then adding lime into the ceramic powder, mixing and pressing the mixture into balls; finally sintering for half an hour at 950 ℃ and then sintering for 1 hour at 1200 ℃ to obtain a ceramic body; adding butyl acrylate, N-hydroxymethyl acrylamide, styrene and isomeric tridecanol polyoxyethylene ether into water to prepare emulsion; and then dropwise adding a potassium persulfate aqueous solution, and reacting at 70-75 ℃ for 1.5-2 hours to obtain the inert polymer slurry. Dispersing the ceramic body in ethanol, and then adding slurry of an inert polymer; mixing for 2 hours, and then adding maleic anhydride and diethyl phosphite; mixing for 2 hours; and then removing the solvent, and treating at 120-135 ℃ for 20 minutes to coat an inert polymer layer on the outer surface of the ceramic body to obtain the grinding ball. The mass ratio of the ceramic body, the inert polymer, the maleic anhydride and the diethyl phosphite is 1: 0.4: 0.1: 0.05; the mass ratio of silicon dioxide, boron oxide, yttrium oxide, magnesium oxide and boron oxide is 5: 1: 0.5: 2: 2.5; the mass ratio of butyl acrylate, N-hydroxymethyl acrylamide, styrene, isomeric tridecanol polyoxyethylene ether, water and potassium persulfate is 5: 18: 35: 20: 100: 1; the thickness of the inert polymer layer is 0.2-0.3 microns.

Example one

Referring to fig. 1, a sludge treatment device comprises a paddle sludge cooler 1, a belt type freezer 2, a ball mill 3, a conveying screw 4, a centrifuge 5, a refrigerator 6 and a sludge pump 7 which are sequentially communicated; the sludge cooling machine is provided with a cooling fluid inlet and a cooling fluid outlet; the refrigerator is provided with a frozen gas inlet and a frozen gas outlet (positioned at the bottom); the ball mill is provided with a cooling gas inlet and a cooling gas outlet, grinding balls are arranged inside the ball mill, and the arrangement mode of the grinding balls is conventional; the conveying screw is provided with a heating fluid inlet and a heating fluid outlet; the centrifuge is provided with a clear liquid outlet 8; the refrigerator is provided with an air inlet and an air outlet; a cooling fluid inlet of the sludge cooler is communicated with a heating fluid outlet of the conveying screw, and a cooling fluid outlet of the sludge cooler is communicated with a heating fluid inlet of the conveying screw, so that fluid can circulate between the cooler and the conveying screw to drive heat to be conveyed; the air inlet of the refrigerator is communicated with the freezing gas outlet of the refrigerator and the cooling gas outlet of the ball mill, and the air outlet of the refrigerator is communicated with the freezing gas inlet of the refrigerator and the cooling gas inlet of the ball mill. In fig. 1, the direction of a single arrow is a sludge conveying direction, the direction of a double arrow is a gas conveying direction, and the direction of a triple arrow is a fluid conveying direction; the sludge sequentially passes through a sludge pump, a paddle sludge cooler, a belt type refrigerator, a ball mill, a conveying screw and a centrifuge; the cooling gas is discharged from the refrigerator and supplied to the refrigerator and the ball mill; the fluid circulates between the cooler and the conveying screw to drive heat to be conveyed.

Adopt above-mentioned equipment to carry out the sludge dewatering: municipal sludge with the water content of 80% is conveyed to a sludge cooling machine by a sludge pump, the sludge cooling machine adopts paddle type cooling equipment to cool the sludge in an indirect heat exchange mode, a cooling medium comes from a conveying screw, and the temperature of the sludge is reduced to 5 ℃ from normal temperature after heat exchange and temperature reduction. The sludge cooled by the paddle cooler enters the belt type refrigerating machine, and in the belt type refrigerating machine, low-temperature cooling gas enters the refrigerating machine from the bottom and is in direct contact with the sludge, so that the temperature of the sludge is reduced. The temperature of the sludge is further reduced along with the conveying of the sludge on the belt, and the temperature of the sludge discharged from the refrigerator is controlled to be-10 ℃ according to different sludge properties. Along with the reduction of the temperature of the sludge, the structure of the sludge is changed, liquid water is changed into solid water, and simultaneously the microbial structure of the sludge is destroyed. The gas exhausted from the refrigerator is cooled by the refrigerator and then reused. The sludge discharged from the freezer enters a ball mill, the solid sludge is crushed under the action of the grinding balls, and the physical and biological structures of the sludge are further destroyed. Introducing cooling gas into the ball mill, and maintaining the temperature in the ball mill at-20 ℃. Conveying the sludge conveyed out of the ball mill to a centrifugal machine through a conveying screw, introducing heat exchange medium water into a conveying screw jacket, heating the sludge to normal temperature after the sludge absorbs heat, converting the sludge into liquid, and cooling the sludge in a paddle cooler after the water exchanges heat. After the liquid sludge is dewatered by a centrifugal separation machine with the rotating speed of 3500 rpm and the time of 3 minutes, the water content of the sludge can be reduced to 30 percent.

Example two

A kind of sludge treatment equipment, similar to embodiment, including the paddle sludge cooler, belt freezer, ball mill (with ball mill), conveying the spiral, centrifuge that communicate sequentially, also include the refrigerator, sludge pump; the refrigerator still is equipped with temperature sensing probe, prevents that freezing broken wall key parameter from going out the problem, effectively monitors the temperature of freezing mud, guarantees freezing dewatering quality.

Adopt above-mentioned equipment to carry out the sludge dewatering: municipal sludge with the water content of 80% is conveyed to a sludge cooling machine by a sludge pump, the sludge cooling machine adopts paddle type cooling equipment to cool the sludge in an indirect heat exchange mode, a cooling medium comes from a conveying screw, and after the heat exchange cooling, the temperature of the sludge is reduced to 10 ℃ from normal temperature. The sludge cooled by the paddle cooler enters the belt type refrigerating machine, and in the belt type refrigerating machine, low-temperature cooling gas enters the refrigerating machine from the bottom and is in direct contact with the sludge, so that the temperature of the sludge is reduced. The temperature of the sludge is further reduced along with the conveying of the sludge on the belt, and the temperature of the sludge discharged from the refrigerator is controlled to be-5 ℃ according to different sludge properties. Along with the reduction of the temperature of the sludge, the structure of the sludge is changed, liquid water is changed into solid water, and simultaneously the microbial structure of the sludge is destroyed. The gas exhausted from the refrigerator is cooled by the refrigerator and then reused. The sludge discharged from the freezer enters a ball mill, the solid sludge is crushed under the action of the grinding balls, and the physical and biological structures of the sludge are further destroyed. Introducing cooling gas into the ball mill, and maintaining the temperature in the ball mill at-15 ℃. Conveying the sludge conveyed out of the ball mill to a centrifugal machine through a conveying screw, introducing heat exchange medium water into a conveying screw jacket, heating the sludge to normal temperature after the sludge absorbs heat, converting the sludge into liquid, and cooling the sludge in a paddle cooler after the water exchanges heat. After the liquid sludge is subjected to centrifugal separation mechanical dehydration at the rotating speed of 2800 revolutions per minute for 2 minutes, the water content of the sludge can be reduced to 32 percent.

Claims

1. The utility model provides a mud treatment is ball for equipment which characterized in that: the grinding ball comprises a ceramic body and an inert polymer layer coated on the outer surface of the ceramic body; the thickness of the inert polymer layer is 0.2-0.3 microns; the preparation of the grinding ball comprises the following steps:

(1) mixing silicon dioxide, boron oxide, yttrium oxide, magnesium oxide and boron oxide to prepare mixed powder; smelting the mixed powder at 1500 ℃ for 1 hour, and quenching to obtain a block; crushing the block, and sieving the crushed block through a 325-mesh standard sieve to obtain ceramic powder; then adding lime into the ceramic powder, mixing and pressing the mixture into balls; finally sintering for half an hour at 950 ℃ and then sintering for 1 hour at 1200 ℃ to obtain a ceramic body;

(2) adding butyl acrylate, N-hydroxymethyl acrylamide, styrene and isomeric tridecanol polyoxyethylene ether into water to prepare emulsion; then dropwise adding a potassium persulfate aqueous solution, and reacting at 70-75 ℃ for 1.5-2 hours to obtain inert polymer slurry;

(3) dispersing the ceramic body in ethanol, and then adding slurry of an inert polymer; mixing for 2 hours, and then adding maleic anhydride and diethyl phosphite; mixing for 2 hours; and then removing the solvent, treating at 120-135 ℃ for 20 minutes, and coating an inert polymer layer on the outer surface of the ceramic body to obtain the grinding ball.

2. The grinding ball for sludge treatment equipment according to claim 1, wherein: the mass ratio of the silicon dioxide, the boron oxide, the yttrium oxide, the magnesium oxide and the boron oxide is 5: 1: 0.5: 2: 2.5.

3. The grinding ball for sludge treatment equipment according to claim 1, wherein: the mass ratio of butyl acrylate, N-hydroxymethyl acrylamide, styrene, isomeric tridecanol polyoxyethylene ether, water and potassium persulfate is 5: 18: 35: 20: 100: 1.

4. The grinding ball for sludge treatment equipment according to claim 1, wherein: the mass ratio of the ceramic body, the inert polymer and the maleic anhydride to the diethyl phosphite is 1: 0.4: 0.1: 0.05.