JP2005103397A - Drying device for wastewater sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an efficient drying device for wastewater sludge which can reduce energy consumption and equipment costs, and treat the sludge in a short time. <P>SOLUTION: This drying device for the wastewater sludge has a dehydrator 10 for dehydrating the wastewater sludge generated in a coating process to generate dehydrated sludge, a crusher 20 for crushing the dehydrated sludge to generate sludge granules, a circulator 30 having a circulation passage connected to the crusher 20 and a blower 34 installed in the circulation passage and circulating the sludge granules by ventilation by the blower 34, and a sorter 40 installed in the middle of the circulation passage and sorting the sludge granules into dried granules and undried granules. The dried granules are discharged outside, and the undried granules are returned into the circulation passage to be recirculated by the ventilation. The sludge granules and undried granules can be always uniformly exposed to the ventilation, thereby they can be dried efficiently. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus for drying wastewater sludge generated in a painting process.

  In general, the painting process performed on automobile bodies, machine parts, etc. includes a pretreatment process performed prior to the application of paint, an electrodeposition coating process (undercoating process), and an intermediate coating process performed as necessary. The top coating process mainly consists of finish painting.

  In the pretreatment process, a degreasing process to remove oil attached to the surface of the object to be coated, or a chemical conversion process to improve the corrosion resistance and adhesion of the coating film by forming a chemical film by chemical or electrical reaction. Is done. In the electrodeposition coating process, metal is not eluted from the object to be coated, and cationic electrodeposition having excellent rust resistance is the mainstream. In this electrodeposition coating process, the object to be coated that has undergone the pretreatment process is immersed in an aqueous cationic electrodeposition coating liquid, and the direct current is applied to the object to be coated and the coating tank (in the case of cationic electrodeposition, the object to be coated is the cathode). By applying a voltage, an electrodeposition coating film is formed on the object to be coated. In the intermediate coating process, coating is performed to prevent chipping and improve the top coat finish. In the top coating process, air spray or electrostatic coating is applied as the final finish of the coating.

  In the pretreatment step and the undercoat step among the coating steps, water washing is performed after the chemical conversion treatment and after the electrodeposition coating treatment for the purpose of preventing mixing of the treatment liquid and ensuring the quality of the chemical conversion coating and the quality of the coating coating, respectively. A large amount of drainage occurs. The wastewater generated by water washing after these chemical conversion treatments and electrodeposition coating treatments is obtained by aggregating colloidal particles in the wastewater by using a flocculant such as iron sulfate and a pH adjusting agent such as calcium hydroxide, thereby draining sludge. (Aggregated precipitate) (see Patent Document 1). In addition, each of the waste water after the chemical conversion treatment and the waste water after the electrodeposition treatment is treated alone, or both are mixed and treated.

The wastewater sludge after chemical conversion treatment and electrodeposition coating treatment thus obtained contains water and solvent at a liquid content of about 90% (% means mass%, hereinafter the same), and is pressed by a press. Thus, a cake-like drainage sludge having a liquid content of about 65 to 75% is obtained. And this cake-form drainage sludge is incinerated after incineration, or is dried by heat or ventilation, and is made into a liquid content of about 30 to 40%, and then incinerated.
JP-A-9-170098 (page 2)

  However, when incinerating the wastewater sludge, there is a problem that a great deal of energy is consumed. Moreover, when drying by heat, since facilities, such as a steam, an electric heater, and a burner, are required, there exists a problem that the expense invested in these facilities is large. On the other hand, when drying by blowing, it is advantageous in terms of cost, but normally it blows against drainage sludge piled up on a pallet etc., so the internal sludge cannot be exposed to the wind and it is dry There is a problem that it takes time.

  The present invention has been made in view of the above circumstances, and can solve the problem of providing an efficient drainage sludge drying apparatus that can reduce energy consumption and equipment costs and can be processed in a short time. It is to be an issue.

  The apparatus for drying wastewater sludge of the present invention that solves the above problems includes a dewatering apparatus for dewatering sludge generated in the painting process to form dewatered sludge, a crushing apparatus for crushing the dewatered sludge to sludge fine particles, A circulation device connected to the crushing device and a blower provided in the circulation route, and a circulation device for circulating the sludge fine particles in the circulation route by the blower of the blower, and provided in the middle of the circulation route And a sorting device that selects the sludge fine particles as dry fine particles and non-dry fine particles, and discharges the dry fine particles to the outside, while returning the non-dry fine particles into the circulation path by the air blowing. The inside of the circulation path is recirculated.

  In this drainage sludge drying apparatus, drainage sludge generated in the painting process is dehydrated by a dehydrator to obtain dehydrated sludge, and then the dewatered sludge is crushed by a crusher to obtain sludge fine particles. The sludge fine particles are circulated by the air blower in the circulation path of the circulation device. At this time, the water-containing sludge fine particles are gradually removed while circulating in the circulation path by blowing air. Then, by a sorting device provided in the middle of the circulation path, the sludge fine grains are sorted into dry fine grains and undried fine grains, and the dry fine grains are discharged to the outside, while the undried fine grains are disposed in the circulation path. And then recirculated by blowing air.

  The sludge fine particles crushed by the crusher and the undried fine particles that have been sorted by the sorting device and returned to the circulation path are circulated by blowing in the circulation path, so that these sludge fine grains and undried fine grains are always collected. It can be evenly exposed to air and can be efficiently dried. Also, in the sorting device provided in the middle of the circulation path, the dried fine granules are sorted and discharged, so the sludge fine particles crushed by the crushing device and the sorting device are sorted and recirculated. Only undried fines will circulate in the circuit. That is, the fine particles circulating in the circulation path are only fine grains that contain moisture and need to be dried, and dry fine grains that have already been dried and do not require further drying do not circulate in the circulation path. For this reason, in the circulation path, drying by blowing air on the sludge fine particles and undried fine particles is not hindered by the undried fine particles, and drying efficiency by blowing air in the circulation path is improved. Therefore, sludge fine particles and the like can be efficiently dried in a short time.

  In addition, in this wastewater sludge drying device, sludge is dried by a simple mechanism of circulating in the circulation path by blowing air, so that a large amount of energy is consumed as in the case of incineration treatment or when drying by heat There is no need for such a large capital investment.

In a preferred aspect, the sorting device includes a chamber having at least a ventilation port connected to the circulation path and a discharge port communicating with the outside, and a baffle plate disposed in the chamber, through the ventilation port. The sludge fine particles introduced by the air flow from the circulation path into the chamber are collided with the baffle plate to divide the dry fine particles into light dry fine particles and heavy undried fine particles. While discharging from the outlet, the undried fine particles are returned to the circulation path and recirculated.

  In the sorting device in the drainage sludge drying device, sludge fine particles are introduced into the chamber from the circulation path through the air blowing port. Sludge fine particles introduced into the chamber by blowing air collide with a baffle plate disposed in the chamber, thereby removing dry fine particles from which moisture has been removed and heavy undried fine particles containing moisture. And divided. And the dry fine granule which does not need to dry any more is discharged | emitted from the discharge port outside. On the other hand, the undried fine particles that contain moisture and still need to be dried are returned to the circulation path from the air blowing port or a separately provided circulation port and recirculated. As described above, according to this sorting apparatus, the dry fine particles and the non-dried fine particles are sorted by specific gravity using a very simple mechanism in which sludge fine particles introduced by blowing air into the chamber collide with the baffle plate. This contributes to cost reduction of equipment.

  In a preferred aspect, the chamber further includes a circulation port connected to the circulation path and for returning the undried fine particles to the circulation path. According to this aspect, since the circulation port for returning the undried fine particles to the circulation path is provided separately from the ventilation port for introducing the sludge fine particles into the chamber by blowing from the circulation path, The dry fine particles can be returned to the circulation path and recirculated by using the flow of air sent from the air to the circulation port through the baffle plate. For this reason, it is possible to recirculate the undried fine particles more smoothly compared to the case where the undried fine particles are returned from the blower port to the circulation path and recirculated.

  In a preferred aspect, the crushing device is provided with a mesh cylinder having an inlet to which the dewatered sludge is introduced at one end thereof, and is rotatably disposed in the mesh cylinder, and the dewatered sludge is introduced into the mesh cylinder from the inlet. A stirring shaft having an outer peripheral surface provided with a stirring blade that moves toward the other end of the mesh cylinder; and a driving unit that rotationally drives the stirring shaft, and the pitch of the stirring blade is changed from the introduction port to the other end. It is set to narrow toward the side.

  In the crushing device in this drainage sludge drying device, the dewatered sludge introduced into the mesh cylinder from the introduction port is transferred to the back side (the other end side) of the mesh cylinder by the stirring blade of the stirring shaft that is rotationally driven by the driving means. Is done. At this time, since the pitch of the stirring blades is set so as to become narrower from the inlet to the back side, the volume of the transfer space into which the dewatered sludge enters, that is, the partition is formed by the stirring shaft, the mesh cylinder, and the stirring blades. The volume of the transfer space is reduced toward the inner side of the mesh cylinder. For this reason, as it goes to the inner side of the mesh cylinder, a stronger compaction force acts on the dewatered sludge. Accordingly, the dewatered sludge is strongly pressed and rubbed against the radially outer mesh cylinder. The dewatered sludge rubbed onto the mesh cylinder is rubbed down by the mesh cylinder mesh, and sludge fine particles crushed to a size smaller than the mesh size are discharged to the outside from the mesh. Therefore, according to this crushing device, by supplying dewatered sludge continuously to the inlet of the mesh cylinder, the dewatered sludge is continuously crushed and crushed to a size less than the mesh size of the mesh cylinder. Grains can be obtained continuously. And it becomes possible to improve the drying efficiency by ventilation by crushing sludge finely and enlarging the specific surface area of sludge.

  In a preferred aspect, the crushing device is provided with a mesh cylinder having an inlet to which the dewatered sludge is introduced at one end thereof, and is rotatably disposed in the mesh cylinder, and the dewatered sludge is introduced into the mesh cylinder from the inlet. A stirring shaft having an outer peripheral surface provided with a stirring blade that moves toward the other end side of the mesh cylinder; and a driving unit that rotationally drives the stirring shaft, the stirring shaft from the introduction port to the other end side Conical shape with outer diameter increasing toward

  In the crushing device in this drainage sludge drying device, the dewatered sludge introduced into the mesh cylinder from the introduction port is transferred to the back side (the other end side) of the mesh cylinder by the stirring blade of the stirring shaft that is rotationally driven by the driving means. Is done. At this time, since the stirring shaft has a cone shape whose outer diameter increases from the introduction port toward the back side, the volume of the transfer space into which the dewatered sludge enters, that is, the stirring shaft, the mesh cylinder, and the stirring blades. The volume of the formed transfer space is reduced toward the inner side of the mesh cylinder. For this reason, as it goes to the inner side of the mesh cylinder, a stronger compaction force acts on the dewatered sludge. Accordingly, the dewatered sludge is strongly pressed and rubbed against the radially outer mesh cylinder. The dewatered sludge rubbed onto the mesh cylinder is rubbed down by the mesh cylinder mesh, and sludge fine particles crushed to a size smaller than the mesh size are discharged to the outside from the mesh. Therefore, according to this crushing device, by supplying dewatered sludge continuously to the inlet of the mesh cylinder, the dewatered sludge is continuously crushed and crushed to a size less than the mesh size of the mesh cylinder. Grains can be obtained continuously. And it becomes possible to improve the drying efficiency by ventilation by crushing sludge finely and enlarging the specific surface area of sludge.

  In a preferred embodiment, the air used in the circulation device is at room temperature. According to this aspect, since it dries only by normal temperature ventilation, without using heat sources, such as steam and electricity, an installation cost and a running cost can be reduced. Of course, hot air may be used in the circulation device.

  In a preferred aspect, the wastewater sludge is wastewater sludge after at least one of chemical conversion treatment and electrodeposition coating treatment.

  The drainage sludge generated in the coating process includes drainage sludge (so-called paint soot) generated in the intermediate coating process and the top coating process in addition to the drainage sludge after the chemical conversion treatment and the electrodeposition coating treatment. The drainage sludge drying apparatus of the present invention can be applied to drying the paint soot generated in the intermediate coating process and the top coating process, but generally has a lower viscosity than the paint soot. In other words, the wastewater sludge after at least one of the chemical conversion treatment and the electrodeposition coating treatment can be used more suitably. The drainage sludge after the chemical conversion treatment and the drainage sludge after the electrodeposition coating treatment may be used alone or in combination.

  In the wastewater sludge drying apparatus of the present invention, wastewater sludge containing water and a solvent with a liquid content of about 65 to 75% is suitably used as the object to be dried. And according to the drainage sludge drying device of the present invention, this drainage sludge can be dried to a liquid content of about 40 to 45%.

  Therefore, according to the wastewater sludge drying apparatus of the present invention, drying can be performed extremely efficiently by circulating only sludge fine granules and undried fine granules containing moisture while excluding dried fine granules. Therefore, the wastewater sludge can be efficiently dried in a short time while suppressing energy consumption and facility costs.

  In particular, when the sorting apparatus according to claim 2 or 3 is employed, it is possible to sort dry fine particles and non-dried fine particles by specific gravity with a very simple mechanism, so that the equipment cost can be reduced. Become.

  Moreover, when the crushing apparatus of Claim 4 or 5 is employ | adopted, since sludge can be crushed with simple components, such as a mesh cylinder and a stirring shaft, it becomes possible to reduce an installation cost.

  Furthermore, when the sludge is circulated and dried by blowing at room temperature, the running cost is reduced by the amount not using a heat source for drying.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

(Embodiment 1)
The drainage sludge drying apparatus according to this embodiment is intended for drying wastewater sludge after chemical conversion treatment and electrodeposition coating treatment in a painting process performed on the body of an automobile. That is, in this embodiment, polyiron as a flocculant and NaOH as a pH adjuster are added to a mixture of waste water after chemical conversion treatment and waste water after electrodeposition coating treatment to add colloidal particles in the waste water. By agglomerating, wastewater sludge having a liquid content of about 90% was obtained, and this was set as a drying target.

  As shown in FIG. 1, the wastewater sludge drying device includes a dewatering device 10 that dehydrates wastewater sludge generated in the painting process to form dehydrated sludge, and a crushing device 20 that crushes the dewatered sludge into sludge fine particles. The circulation device 30 for circulating the sludge fine particles and the sorting device 40 for selecting the sludge fine particles into dry fine particles and non-dry fine particles are provided.

  The dewatering device 10 includes a centrifuge 11 that dewaters wastewater sludge to obtain dewatered sludge, and a belt conveyor 12 that continuously supplies the dewatered sludge obtained by the centrifuge 11 to the crushing device 20. . In this centrifuge 11, the drainage sludge having a liquid content of about 90% is dewatered to obtain a dewatered sludge having a liquid content of about 70%.

  As shown in FIG. 2, the crushing device 20 has an introduction port 21 through which dewatered sludge is introduced from the belt conveyor 11 at one end (the left end of the mesh cylinder 22 shown in FIG. 2, hereinafter the same). A mesh cylinder 22 is rotatably arranged in the mesh cylinder 22, and the dewatered sludge is introduced from the introduction port 21 to the other end of the mesh cylinder 22 (the right end of the mesh cylinder 22 shown in FIG. 2, hereinafter the same). An agitation shaft 24 provided on the outer peripheral surface is provided with an agitation blade 23 that moves toward the outside, and an electric motor 25 as a drive means for driving the agitation shaft 24 to rotate. And the stirring blade 23 of the stirring shaft 24 in this crushing apparatus 20 is set so that a pitch may become narrow toward the other end side of the mesh cylinder 22 from the inlet 21 provided in the end of the mesh cylinder 22. FIG. Specifically, the pitch of the stirring blades 23 is set such that the maximum one end side of the mesh cylinder 22 is P1 = 10 cm, and the other end side of the mesh cylinder 22 is the minimum 2 cm. As it goes to the side, P1> P2> P3>. Note that the mesh (mesh opening) in the mesh cylinder 22 has a square shape with a side of about 2 mm.

  The circulation device 30 has a bottom opening 31a and a side opening 31b on the bottom and upper side walls, respectively, and a funnel-shaped collection unit 31 for collecting sludge fine particles crushed by the crushing device 20, and a collection unit The first circulation path 32 having one end connected to the bottom opening 31a of the 31, the second circulation path 33 having one end connected to the side opening 31b of the recovery part 31, and the first in the vicinity of the bottom opening 31a. And a blower 34 provided in the circulation path 32. The collection unit 31 is disposed below the mesh cylinder 22, and the maximum width of the upper opening of the collection unit 31 is substantially equal to the length of the mesh cylinder 22.

  The sorting device 40 is disposed between the first circulation path 32 and the second circulation path 33. The sorting device 40 is a chamber having a blower port 41a connected to the other end of the first circulation path 32, a circulation port 41b connected to the other end of the second circulation path 33, and a discharge port 41c connected to the outside. 41 and a baffle plate 42 disposed in the chamber 41. Here, the air blowing port 41a opens in the center of the bottom of the chamber 41, the circulation port 41b opens in the middle of the side wall of one side of the chamber 41 (left side in FIG. 1), and the discharge port 41c extends in the other side of the chamber 41 (in FIG. 1). It opens at the upper end of the right side wall. The chamber 41 has a substantially rectangular parallelepiped shape, and the baffle plate 42 has a rectangular shape equivalent to the cross-sectional shape of the internal space of the chamber 41. The baffle plate 42 extends substantially horizontally at a position slightly above the circulation port 41b at a substantially central portion of the chamber 41, and faces the blower port 41a so as to face the ceiling portion of the chamber 41 through the mounting portion 42a. It is suspended and fixed from the center. The size of the baffle plate 42 is smaller than the inner space of the chamber 41, and the dry fine particles are raised between the periphery of the baffle plate 42 and the inner wall surface of the chamber 41 to guide it to the discharge port 41c. The gap is formed.

  The bottom opening 31a of the collection unit 31 and the air blowing port 41a of the chamber 41 are connected by the first circulation path 32, and the side opening 31b of the collection unit 31 and the circulation opening 41b of the chamber 41 are the second circulation path. 33 are connected. The discharge port 41 c of the chamber 41 is connected to an external collection tank 44 through a discharge pipe 43. Thus, the blower 34 of the circulation device 30 causes the flow of the circulated air to flow through the collection unit 31, the first circulation path 32, the chamber 41 (lower part) and the second circulation path 33 in order, and the first circulation path 32. From the inside of the chamber 41 and through the discharge pipe 43, a flow of air flowing in sequence to the recovery tank 44 is generated.

  The wastewater sludge was continuously dried as follows using the wastewater sludge drying apparatus of the present embodiment having the above-described configuration.

  First, the drainage sludge after chemical conversion treatment and electrodeposition coating treatment was prepared. And in the state which operated the centrifugal separator 11 and belt conveyor 12 of the dehydration apparatus 10, the electric motor 25 of the crushing apparatus 20, and the air blower 34 of the circulation apparatus 30, the wastewater sludge is continuously supplied to the dehydration apparatus 10, The drainage sludge was continuously dried by the drying apparatus of this embodiment.

  That is, in the dehydrating apparatus 10, the drainage sludge is continuously dehydrated by the centrifuge 11 to be dehydrated sludge. The dewatered sludge is continuously supplied to the crushing device 20 by the belt conveyor 12.

  In the crushing device 20, the dewatered sludge introduced continuously into the mesh cylinder 22 from the introduction port 21 is moved to the back side (the other end side) of the mesh cylinder 22 by the stirring blades 23 of the stirring shaft 24 that is rotationally driven by the electric motor 25. ). At this time, since the pitch of the stirring blades 23 is set so as to become narrower from the inlet 21 toward the inner side of the mesh cylinder 22, the volume of the transfer space into which the dewatered sludge enters, that is, the stirring shaft 24, the mesh cylinder The volume of the transfer space defined by the 22 and the stirring blades 23 decreases toward the back side of the mesh cylinder 22. For this reason, as it goes to the inner side of the mesh cylinder 22, a stronger consolidation force acts on the dewatered sludge. Therefore, the dewatered sludge is strongly pressed and rubbed against the mesh cylinder 22 on the radially outer side. The dewatered sludge rubbed against the mesh cylinder 22 is rubbed down by the mesh cylinder 22, and sludge fine particles crushed below the mesh size are discharged from the mesh. And this sludge fine particle is continuously collect | recovered by the collection | recovery part 31 of the said circulator 30. FIG.

  The sludge fine particles collected in the collection unit 31 are guided into the first circulation path 32 from the bottom opening 31a of the collection unit 31 and are circulated by the blower 34 of the circulation device 30 to cause the first circulation path 32 to circulate. And it guide | induces in the chamber 41 of the sorting device 40 through the ventilation port 41a.

  In the sorting device 40, sludge fine particles introduced by blowing air from the first circulation path 32 into the chamber 41 through the blower port 41a move upward in the chamber 41 and collide with the baffle plate 42 from below. The dried fine granules are lightened by removing moisture, and the dried fine granules containing water are heavy. Light dry fine particles that do not need to be dried further rise in the chamber 1 by air blowing, are discharged to the outside through the discharge port 41 c, and are collected in the collection tank 44 through the discharge pipe 43. On the other hand, the heavy undried fine particles that contain moisture and still need to be dried do not rise above the baffle plate 42 and ride on the circulating air flow from the blower 34 to the second circulation from the circulation port 41b. Returned to path 33 and recirculated.

  Thus, the sludge fine particles obtained by being crushed by the crushing device 20 are blown by the blower 34 in the circulation path constituted by the recovery unit 31, the first circulation path 32, the chamber 41 and the second circulation path 33. It is circulated by. At this time, the water-containing sludge fine particles are gradually removed while circulating in the circulation path by blowing air. Then, the sludge fine particles are sorted into dry fine particles and undried fine particles by the sorting device 40 provided in the middle of the circulation path, and the dry fine particles are discharged to the external collection tank 44, while the undried fine particles are discharged. The grains are returned to the circulation path, recirculated by blowing, and dried again by blowing.

  The sludge fine particles crushed by the crushing device 20 and the undried fine particles sorted by the sorting device 40 and returned to the circulation path are circulated by blowing in the circulation path, so that these sludge fine grains and undried fine granules are circulated. Can be exposed to the air evenly and can be efficiently dried. Further, since the dried dry fine particles are sorted and discharged in the sorting device 40, only the sludge fine particles crushed by the crushing device 20 and the undried fine particles sorted and recirculated by the sorting device 40 are used. Will circulate through the circuit. That is, the fine particles circulating in the circulation path are only fine particles that contain moisture and need to be dried (sludge fine particles and undried fine particles), and dry fine particles that have been dried and do not require further drying circulate. There is no circulation in the road. For this reason, in the circulation path, drying by blowing air on the sludge fine particles and undried fine particles is not hindered by the undried fine particles, and drying efficiency by blowing air in the circulation path is improved. Therefore, sludge fine particles and the like can be efficiently dried in a short time.

  Moreover, in this wastewater sludge drying device, sludge is dried by a simple mechanism that circulates sludge fine particles etc. in the circulation path by air blowing at room temperature, so it consumes a lot of energy as in incineration. There is no need for a large capital investment as in the case of drying by heat.

  Furthermore, in the sorting device 40 in the drainage sludge drying device, the dried fine particles and the undried fine particles are made by using a very simple mechanism of causing the sludge fine particles introduced into the chamber 41 by air blowing to collide with the baffle plate 42. Can be sorted by specific gravity, which contributes to cost reduction of equipment. Further, in order to recirculate undried fine particles back to the second circulation passage 33 in the chamber 41 separately from the air blowing port 41a for introducing sludge fine particles into the chamber 41 by blowing from the first circulation passage 32. Since the circulation port 41b is provided, the dry fine particles are returned to the second circulation path 33 and recirculated by using the flow of air from the blower port 41a through the baffle plate 42 to the circulation port 41b. Can do. For this reason, it becomes possible to recirculate the undried fine particles more smoothly compared to the case where the undried fine particles are returned to the first circulation path 32 from the blower port 41a and recirculated.

  In addition, in the crushing device 20 in the drainage sludge drying device, the dewatered sludge is continuously crushed by continuously supplying the dehydrated sludge to the inlet 21 of the mesh cylinder 22 to thereby mesh the mesh of the mesh cylinder 22. Sludge fine particles crushed to below the size can be obtained continuously. Therefore, it becomes possible to improve the drying efficiency by ventilation by crushing sludge finely and increasing the specific surface area of the sludge. Moreover, since sludge can be crushed by simple components such as the mesh cylinder 22 and the stirring shaft 24, the equipment cost can be reduced.

  Furthermore, in this drainage sludge drying apparatus, the air used to circulate sludge fine particles and the like in the circulation device 30 is at room temperature, and the sludge is dried only at room temperature without using a heat source such as steam or electricity. Therefore, equipment costs and running costs can be reduced.

  Thus, in the drainage sludge drying apparatus of the present embodiment, the wastewater sludge having a liquid content of about 70% after the chemical conversion treatment and the electrodeposition coating treatment is used as an object to be dried, and the wastewater sludge has a liquid content of about 40%. Can be dried.

  Therefore, according to the drainage sludge drying apparatus of the present embodiment, it is extremely efficient by circulating only the sludge fine particles containing water and the undried fine particles by blowing air at room temperature while eliminating the dried fine particles. Therefore, the wastewater sludge can be efficiently dried in a short time while suppressing energy consumption and equipment costs.

(Embodiment 2)
The drainage sludge drying apparatus of the present embodiment has the same configuration as that of the first embodiment except that the crushing apparatus 50 shown in FIG. 3 is adopted.

  This crushing apparatus 50 includes a mesh cylinder 52 made of SUS having an inlet 51 into which dewatered sludge is introduced from the belt conveyor 11 at one end (the left end of the mesh cylinder 52 shown in FIG. 3; hereinafter the same), and the mesh cylinder. An agitating blade 53 that is rotatably disposed in 52 and transfers the dewatered sludge from the introduction port 51 toward the other end of the mesh cylinder 52 (the right end of the mesh cylinder 52 shown in FIG. 3; hereinafter the same). An agitation shaft 54 provided on the outer peripheral surface and an electric motor 55 as a driving means for rotating the agitation shaft 54 are provided. The stirring shaft 54 in the crushing device 50 has a cone shape in which the outer diameter gradually increases from the inlet 51 provided at one end of the mesh cylinder 52 toward the other end side of the mesh cylinder 52. Specifically, the outer diameter of the agitation shaft 54 is such that one end of the mesh cylinder 52 is a minimum of 40 cm and the other end of the mesh cylinder 52 is a maximum of 50 cm. It is set so as to gradually increase gradually as it goes to. The mesh (mesh opening) in the mesh cylinder 52 has a square shape with a side of about 2 mm.

  In the crushing device 50 in this drainage sludge drying device, the dewatered sludge continuously introduced into the mesh cylinder 52 from the inlet 51 is meshed by the mesh cylinder 52 by the stirring blade 53 of the stirring shaft 54 that is rotationally driven by the electric motor 55. It is transferred to the back side (the other end side). At this time, the stirring shaft 54 has a cone shape in which the outer diameter increases from the introduction port 51 toward the inner side of the mesh cylinder 52. Therefore, the volume of the transfer space into which the dewatered sludge enters, that is, the stirring shaft 54, the mesh The volume of the transfer space defined by the cylinder 52 and the stirring blade 53 decreases toward the inner side of the mesh cylinder 52. For this reason, as it goes to the inner side of the mesh cylinder 52, a stronger consolidation force acts on the dewatered sludge. Accordingly, the dewatered sludge is strongly pressed and rubbed against the radially outer mesh cylinder 52. The dewatered sludge rubbed against the mesh cylinder 52 is rubbed down by the mesh cylinder 52, and sludge fine particles crushed below the mesh size are discharged from the mesh. And this sludge fine particle is continuously collect | recovered by the collection | recovery part 31 of the said circulator 30. FIG. Therefore, according to this crushing apparatus, by continuously supplying dehydrated sludge to the inlet 51 of the mesh cylinder 52, the dehydrated sludge is continuously crushed and crushed to a size smaller than the mesh size of the mesh cylinder 52. Sludge fine particles can be obtained continuously. And it becomes possible to improve the drying efficiency by ventilation by crushing sludge finely and enlarging the specific surface area of sludge. Moreover, since sludge can be crushed by simple components such as the mesh cylinder 52 and the stirring shaft 54, the equipment cost can be reduced.

  Other functions and effects are the same as those of the first embodiment.

It is sectional drawing which shows typically the whole structure of the drying apparatus of the waste water sludge which concerns on Embodiment 1. FIG. It is sectional drawing which shows typically the crushing apparatus in the drying apparatus of the wastewater sludge which concerns on Embodiment 1. FIG. It is sectional drawing which shows typically the crushing apparatus in the drying apparatus of the wastewater sludge which concerns on Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Dehydrating device 20, 50 ... Crushing device 21, 51 ... Inlet port 22, 52 ... Mesh cylinder 23, 53 ... Stirring blade 24, 54 ... Stirring shaft 25, 55 ... Electric motor 30 ... Circulating device 31 ... Collection part 32 ... 1st circuit 33 ... 2nd circuit 34 ... Air blower 40 ... Sorting device 41 ... Chamber 41a ... Air supply port 41b ... Circulation port 41c ... Discharge port 42 ... Baffle plate

Claims (7)

  A dewatering device for dewatering sludge generated in the painting process to make dewatered sludge, a crushing device for crushing the dewatered sludge to make sludge fine particles, a circulation path connected to the crushing device, and a circulation path A circulation device that circulates the sludge fine particles in the circulation path by blowing air from the blower, and provided in the middle of the circulation path, the sludge fine grains as dry fine grains and undried fine grains. And a sorting device that selectively sorts the dry fine particles to the outside, and the undried fine particles are returned to the circulation path and recirculated in the circulation path by the blowing. Wastewater sludge drying equipment.   The sorting device includes a chamber having at least a blower port connected to the circulation path and a discharge port leading to the outside, and a baffle plate disposed in the chamber, and is connected to the circulation path via the blower port. The sludge fine particles introduced into the chamber by the blowing are collided with the baffle plate, so that the dry fine particles are divided into light dry fine particles and heavy undried fine particles, and the dry fine particles are discharged from the discharge port. On the other hand, the apparatus for drying wastewater sludge according to claim 1, wherein the undried fine particles are returned to the circulation path and recirculated.   The drainage sludge drying apparatus according to claim 2, wherein the chamber further includes a circulation port connected to the circulation path to return the undried fine particles to the circulation path. The crushing device includes a mesh cylinder having an inlet to which the dewatered sludge is introduced on one end side, and is rotatably disposed in the mesh cylinder. The dewatered sludge is fed from the inlet to the other end of the mesh cylinder. A stirring shaft provided on the outer peripheral surface with stirring blades that move toward the side, and drive means for rotationally driving the stirring shaft,
The drainage sludge drying apparatus according to claim 1, wherein the pitch of the stirring blades is set so as to become narrower from the introduction port toward the other end side. The crushing device includes a mesh cylinder having an inlet to which the dewatered sludge is introduced on one end side, and is rotatably disposed in the mesh cylinder. The dewatered sludge is fed from the inlet to the other end of the mesh cylinder. A stirring shaft provided on the outer peripheral surface with stirring blades that move toward the side, and drive means for rotationally driving the stirring shaft,
The drainage sludge drying apparatus according to claim 1, wherein the stirring shaft has a cone shape with an outer diameter increasing from the inlet to the other end.   6. The apparatus for drying wastewater sludge according to claim 1, wherein the blast used in the circulation device is at room temperature.   7. The drainage sludge drying apparatus according to claim 1, wherein the drainage sludge is drainage sludge after at least one of chemical conversion treatment and electrodeposition coating treatment. .

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