JP2017148767A - Dewatered sludge conveyance system and treatment method before conveyance of dewatered sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve conveyance over a longer distance by maintaining a sol state obtained by applying stress to dewatered sludge for a longer period of time in a conveyance system of dewatered sludge.SOLUTION: In a dewatered sludge conveyance system for conveying dewatered sludge, the dewatered sludge conveyance system comprising a crushing part for crushing dewatered sludge and a kneading part for kneading the dewatered sludge is provided. According to the dewatered sludge conveyance system, an aggregation structure can be destroyed by subjecting dewatered sludge to crushing treatment and kneading treatment and the state of having its viscosity lowered can be maintained for a longer period of time. Therefore, the conveyance for a longer distance can be achieved.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dewatered sludge conveying system for conveying dehydrated sludge, and more particularly to a dehydrated sludge conveying system for conveying dehydrated sludge having a low water content. The present invention also relates to a transport pretreatment method applied to the dewatered sludge before transporting the dewatered sludge, and more particularly to a transport pretreatment method of the dewatered sludge that fluidizes the dehydrated sludge having a low water content.

  In the dewatered sludge conveyance system that conveys the dehydrated sludge with a pump, the flow resistance of the dehydrated sludge is poor, so that the piping resistance is high and long distance conveyance becomes difficult. Therefore, a method is adopted in which dehydrated sludge is resuspended to form a slurry and then conveyed by a pump. However, when the dewatered sludge is resuspended, the problem remains that the water content of the dewatered sludge increases.

  On the other hand, dehydrated sludge usually has a solid appearance, but exhibits a so-called thixotropic property in which a certain amount of stress is applied from the outside to form a sol and become liquid. And the transport system of dehydrated sludge is examined using this thixotropic property.

  For example, Patent Document 1 discloses that a kneader, which is a kneader, is provided at the front stage of a pump as a dewatered sludge transport system in which stress is applied to dehydrated sludge in advance to shift to a sol state and the pump is transported in that state. A dehydrated sludge conveyance system provided is disclosed.

Japanese Patent Publication No.58-25611

However, the sol state obtained by applying stress to the dewatered sludge is a temporary state, and when the application of stress is stopped, it returns to a state with poor fluidity again. Therefore, there exists a subject that piping resistance increases gradually during conveyance with a pump.
Accordingly, an object of the present invention is to maintain the sol state obtained by applying stress to the dewatered sludge for a longer time and realize a longer distance conveyance.

As a result of intensive studies on the above-mentioned problems, the present inventor has found that the sol state can be maintained for a longer time by performing kneading treatment and crushing treatment on the dehydrated sludge, thereby completing the present invention.
That is, the present invention is the following dewatered sludge conveying system and dehydrated sludge conveying pretreatment method.

  The dehydrated sludge conveying system of the present invention for solving the above problems is a dehydrated sludge system for conveying dehydrated sludge, a crushing section for crushing the dehydrated sludge, and a kneading section for kneading the dehydrated sludge. It is characterized by having.

In the dewatered sludge, solids and water form a cohesive structure with a coagulant to increase the structural viscosity. When the kneading process is performed, water oozes out from the aggregate structure due to stress, and the viscosity is temporarily reduced. However, if left as it is, water penetrates into the aggregate structure again to reconstruct the aggregate structure.
However, according to the dewatered sludge conveyance system of the present invention, the aggregated structure can be destroyed by the crushing action and the kneading action in the crushing part and the kneading part. Therefore, the aggregated structure is not immediately reconstructed, and the state in which the viscosity is lowered is maintained for a long time, so that a longer distance can be conveyed.

  Furthermore, as one embodiment of the dewatered sludge transport system of the present invention, the crushing part and the kneading part have a feature that a rotating blade and a scraping member disposed in proximity to the rotating blade are provided.

  By allowing dewatered sludge to flow into the gap between the rotary blade and the scraping member and rotating the rotary blade, the dewatering sludge is scraped off by the gap between the rotary blade and the scraping member. When the dewatered sludge is scraped, the solid particles in the agglomerated structure are sheared, and the sheared agglomerates move while rolling through the gap between the rotary blade and the scraping member. Into small aggregates. Therefore, in the scraping action, both the kneading action and the crushing action can be given to the dewatered sludge. Therefore, according to the above feature, the crushing part and the kneading part can be constituted by one apparatus.

  Furthermore, as one embodiment of the dewatered sludge conveyance system of the present invention, the crushing unit and the kneading unit have a feature that two or more cutter units each having a plurality of rotary blades fixed to a rotary shaft are provided.

Two or more cutter units are installed so that their rotary blades engage with each other, and are configured to rotate inward, thereby scrubbing dewatered sludge at the gap between one rotary blade and the other rotary blade. Can be given. Furthermore, the flow of the dewatered sludge is promoted by the rotation of the cutter units. Therefore, according to the above feature, since the kneading action and the crushing action are efficiently given to the dewatered sludge, the conveyance speed can be increased.
In addition, by configuring the cutter unit, it is possible to easily remove and assemble the rotary blade, and the effect of reducing the replacement work is achieved.

  The pretreatment method for transporting dehydrated sludge according to the present invention for solving the above problems is a pretreatment method for transporting dehydrated sludge, a crushing step for crushing the dehydrated sludge, and a kneading step for kneading the dehydrated sludge. , Provided.

  According to this transporting pretreatment method for dewatered sludge, the dewatered sludge agglomerated structure can be destroyed by the crushing process for crushing the dewatered sludge and the kneading process for kneading the dewatered sludge. Therefore, the aggregated structure is not immediately reconstructed, and the state in which the viscosity is lowered is maintained for a long time, so that a longer distance can be conveyed.

  According to the dewatered sludge conveyance system of the present invention, the sol state obtained by applying stress to the dehydrated sludge can be maintained for a longer time, and longer distance conveyance can be realized.

It is a block diagram for demonstrating the dehydration sludge conveyance system of 1st Example of this invention. It is a schematic explanatory drawing (front view) which shows the structure of the dewatering sludge conveyance system of 1st Example of this invention. It is a schematic explanatory drawing (plan view) which shows the structure of the dehydration sludge conveyance system of 1st Example of this invention. It is a schematic explanatory drawing which shows the change of the dewatering sludge aggregation structure and the state of the dewatered sludge when the kneading action and crushing action are given to the dewatered sludge. It is a block diagram for demonstrating the dehydration sludge conveyance system of the 2nd Example of this invention. It is a block diagram for demonstrating the dehydration sludge conveyance system of the 3rd Example of this invention. It is a schematic explanatory drawing which shows the structure of the dehydration sludge conveyance system of the 3rd Example of this invention. (A) is a front view, (B) is a plan view. It is a schematic explanatory drawing explaining the structure of the kneading | pulverizing crushing part in the dehydration sludge conveyance system of the 3rd Example of this invention. It is a schematic explanatory drawing which shows another shape about the cutter unit and sliding member used for the kneading crushing part of the dehydration sludge conveyance system of this invention. It is a schematic explanatory drawing which shows various shapes about the rotary blade used for the kneading crushing part of the dewatered sludge conveyance system of this invention. It is a schematic explanatory drawing which shows the structure of the dehydration sludge conveyance system of the 4th Example of this invention. (A) is a front view, (B) is a plan view. It is a schematic explanatory drawing (front view) which shows the structure of the dehydration sludge conveyance system of the 5th Example of this invention. It is a schematic explanatory drawing which shows another Example about the kneading crushing part of the dewatered sludge conveyance system of this invention. It is a schematic explanatory drawing which shows another Example about the kneading crushing part of the dewatered sludge conveyance system of this invention.

  The dewatered sludge conveyance system of the present invention is a system for conveying dehydrated sludge. Here, dewatered sludge is a dewatered cake obtained by dewatering sludge with a dehydrator. For example, sludge generated at a sewage treatment plant or wastewater treatment plant, paper sludge from a paper mill, waste water from a factory such as a food plant or a plating plant. And a dehydrated cake obtained by dehydrating pigment waste water and the like.

  The moisture content of the dewatered sludge is not particularly limited, but is usually 90% or less, preferably 80% or less, and more preferably 75% or less. The sludge having a low water content is difficult to be transported by a pump or the like, and the effects of the dewatered sludge transport system of the present invention can be further exhibited. Moreover, it is preferable that the dewatered sludge has thixotropic properties. The thixotropy is a property that when dehydrated sludge is stressed, it becomes sol and becomes liquid and returns to its original state when left untreated. The dewatered sludge conveying system of the present invention is particularly suitable for conveying dehydrated sludge having thixotropic properties because it has the effect of reducing the thixotropic properties of the dehydrated sludge and maintaining the flow state for a long time.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
In addition, in this specification, the description about each structure of the stirring and mixing apparatus of this invention shall also be described about the process process corresponding to each structure.

[First embodiment]
FIG. 1 is a block diagram illustrating the configuration of a dewatered sludge conveyance system 1 according to the first embodiment of the present invention. FIGS. 2 and 3 illustrate the dewatered sludge conveyance system 1 according to the first embodiment of the present invention. The schematic explanatory drawing which shows a structure is illustrated.

  As illustrated in FIG. 1, the dewatered sludge transport system 1 includes a crushing unit 2 that crushes the dehydrated sludge S, a kneading unit 3 that kneads the dehydrated sludge S crushed by the crushing unit 2, a crushing process, and a kneading process. A dewatering sludge S is provided. The dewatered sludge transport system 1 of the first embodiment processes the crushing unit 2 and the kneading unit 3 in this order, and then transports the dehydrated sludge S by the transport unit 4, but the order of processing steps in the crushing unit 2 and the kneading unit 3 is as follows. Is not particularly limited. Moreover, it is good also as a crushing kneading part which performs crushing and kneading simultaneously.

  A plurality of crushing units 2 and kneading units 3 may be installed, or may be configured in combination with a crushing and kneading unit, and can be appropriately designed according to the state of the dewatered sludge S. Further, these configurations may be installed in the middle of the transport unit 4.

Next, each configuration will be described.
(Crushing part)
The crushing unit 2 is configured to perform an operation of mechanically shearing the dewatered sludge S using a sharp blade or the like. The crushing part 2 of the first embodiment has a casing having an opening that is opened from the upper part toward the lower part in the approximate center, a rotating shaft that is installed across the opening, and a disk-like shape that is fixed to the rotating shaft. The dewatered sludge S, which is an apparatus provided with a cutter, is introduced from the upper inlet, passes through the opening while being mechanically sheared by a rotating disk-shaped cutter, and is discharged from the lower part.

  The configuration of the crushing unit 2 may be any device as long as it is an operation for mechanically shearing the dewatered sludge S with a blade or the like. In addition to the configuration of the first embodiment, for example, a rotating device such as a rotating shaft. In addition, a configuration in which a plurality of blades project from a movable device such as a reciprocating device that reciprocates, a configuration in which dewatered sludge S is passed through a fixed blade fixed to an inner wall surface of a casing, and the like is sheared.

(Kneading part)
The kneading unit 3 is configured to perform an operation for applying stress to the dewatered sludge S, and examples thereof include a kneading device, a kneader, a stirrer, a compressor, and a pulverizer. In the kneading section 3 of the first embodiment shown in FIG. 2, two sets of screws are provided in the casing toward the front of the page, the screw on the left side of the page rotates clockwise, and the screw on the right side of the page rotates counterclockwise. To do. The dewatered sludge S crushed by the crushing unit 2 is introduced into the casing from the opening on the back side of the paper surface of the kneading unit 3 and moved to the front side of the paper surface by the action of two sets of screws. At that time, a twisting stress is applied between the two sets of screws.

  As long as the kneading part 3 is configured to apply stress to the dewatered sludge S, any apparatus may be used. For example, in addition to the configuration provided with the two sets of screws of the first embodiment, for example, a kneading device provided with an axisless screw, a kneader that gives vibration, a stirrer such as a rotating drum, a compression such as a screw type extruder And grinders such as a ball mill and the like.

(Transport section)
The transport unit 4 is configured to transport the dewatered sludge S that has been subjected to the crushing process and the kneading process to a predetermined facility. The conveying unit 4 of the first embodiment is composed of a screw conveyor installed at the lower part of the discharge port of the kneading unit 3 and a uniaxial eccentric screw pump (Mono pump) connected to the tip thereof. The screw conveyor is used as a screw feeder that supplies the dewatered sludge S to the uniaxial eccentric screw pump.

  Any device may be used as the transport unit 4, for example, reciprocating pumps such as piston pumps, plunger pumps, diaphragm pumps, rotary pumps such as gear pumps, vane pumps, screw pumps, screw conveyors, belt conveyors. And conveyors such as bucket conveyors. A reciprocating pump or a rotary pump is preferable from the viewpoint of downsizing the apparatus. In addition, a rotary pump is preferable from the viewpoints of pulsation and quantitative transfer, and a uniaxial eccentric screw pump is particularly preferable from the viewpoint of making the apparatus compact.

  The transport unit 4 may be provided with a structure for supplying a lubricant such as water or a structure for heating the pipe as a structure for promoting the transport. However, it is preferable not to install the structure for supplying the lubricant to the piping in order to increase the moisture content of the dewatered sludge. Moreover, since the structure which heats piping requires the energy of a heating, it is preferable not to install.

(Dehydrated sludge aggregation structure)
Next, with reference to FIG. 4, the aggregation structure of the dewatered sludge S and the change in the state of the dewatered sludge S when the kneading action and the crushing action are applied to the dewatered sludge will be described.

  FIG. 4 (A) is a schematic explanatory view showing the aggregation structure of the dewatered sludge S. FIG. As shown in FIG. 4A, the aggregated structure of the dewatered sludge S is a structure in which the solid particles P are connected by the action of a coagulant and the like, and water W is included therein. When a kneading action is given to this, as shown in FIG. 4B, the structure of the solid particles P is crushed and the contained water exudes. And dehydrated sludge S turns into the sol-like fluid substance which the crushed aggregate disperse | distributed in the exuded water. This sol-like fluid is in a state suitable for transportation because it has fluidity, but the state of FIG. 4B is a temporary state, and the crushed aggregate sucks in the surrounding water and takes a short time. Returning to the state of FIG.

  On the other hand, when the crushing action is applied to the aggregated structure of FIG. 4A, as shown in FIG. 4C, the connection of the solid particles P is sheared (broken line), and the included water is surrounded from the shearing surface. Leak out. The state of FIG. 4C is also sol-like and has fluidity, but if left as it is, the cut surfaces are combined by re-aggregation, returning to the state of FIG. 4A and losing fluidity.

  Therefore, if the dewatered sludge S is crushed to obtain the state shown in FIG. 4C and then further kneaded, the aggregates of the sheared solid particles P are crushed as shown in FIG. 4D. Thus, a denser aggregate is formed. Since these densely aggregated small aggregates are structures that are difficult to reaggregate, it is difficult to return to the state of FIG. 4A, and fluidity can be maintained for a long time.

In addition, after giving the kneading action to the agglomerated structure of FIG. 4 (A), when the crushing action is further given, the state shown in FIG. The fluidity can be maintained for a long time.
In the dewatered sludge transport system and the dewatered sludge pre-transport method according to the present invention, the state shown in FIG. 4D is obtained, so that the effect of excellent transportability is exhibited.

[Second Embodiment]
FIG. 5 is a block diagram illustrating the configuration of the dewatered sludge transfer system 11 according to the second embodiment of the present invention.
In the dewatered sludge conveyance system 11 of the second embodiment, the dewatered sludge S is processed in this order of the kneading unit 3 and the crushing unit 2 and then supplied to the conveyance unit 4. The kneading unit 3, the crushing unit 2, and the conveying unit 4 are provided with a kneading apparatus having two sets of screws and a disk-shaped cutter fixed to the rotating shaft, like the dehydrated sludge conveying system 1 of the first embodiment. And a conveying device comprising a screw conveyor and a uniaxial eccentric screw pump.
Even if it processes in order of the kneading part 3 and the crushing part 2, like the 1st dehydration sludge conveyance system 1, the dehydration sludge conveyance system excellent in the conveyance property can be provided.

[Third embodiment]
FIG. 6 is a block diagram for explaining the configuration of the dewatered sludge conveyance system 12 according to the third embodiment of the present invention. FIG. 7 shows the structure of the dewatered sludge conveyance system 12 according to the third embodiment of the present invention. A schematic explanatory diagram is illustrated.
The dewatered sludge transport system 12 of the third embodiment has a configuration including a kneading and crushing section 5 capable of simultaneously providing a kneading action and a crushing action. The transport unit 4 has the same configuration as that of the first embodiment.

(Kneading crushing part)
The kneading crushing unit 5 has a configuration for performing an operation of applying stress to the dewatered sludge S and an operation of mechanically shearing the dewatered sludge S. The kneading and crushing unit 5 of the third embodiment is an apparatus including a plate-like rotary blade 61 and a plate-like scraping member 64 installed in the vicinity of the surface portion of the rotary blade 61.

  In FIG. 8, the schematic explanatory drawing explaining the structure of the kneading crushing part 5 of the 3rd Example is shown. As shown in FIG. 8, the kneading and crushing unit 5 includes a casing 63 having an opening opened from the upper part toward the lower part in the substantially center, a rotating shaft 62 installed across the opening, and a rotating shaft 62. The apparatus includes a cutter unit 6 having a plurality of fixed disk-shaped rotary blades 61, and a plate-shaped scraping member 64 disposed between the rotary blades 61 on one of the wall surfaces of the opening. The cutter unit 6 rotates so as to move from the upper part to the lower part of the scraping member 64. A blocking plate 65 is attached to the other wall surface of the opening to prevent the dewatered sludge S from staying between the cutter unit 6 and the other wall surface of the opening. According to the kneading and crushing unit 5, the dewatered sludge S input from the upper input port flows into the gap between the rotating rotary blade 61 and the scraping member 64, and the surface portion of the rotary blade 61 and the scraping member 64. It is scraped off by the surface part. When the dewatered sludge S is scraped, the aggregated structure shown in FIG. 4 (A) is sheared in the connection of the solid particles P (state of FIG. 4 (C)), and the sheared aggregate is rotated. While moving while rolling the surface portion of the blade 61 and the surface portion of the scraping member 64, it is crushed into small aggregates (state shown in FIG. 4D).

  FIG. 9 illustrates other shapes of the cutter unit and the scraping member. As illustrated in FIG. 9, the cutter unit 60 includes a plurality of rotary blades 610 each having a curved surface portion. The scraping member 640 is formed according to the shape of the curved surface portion of the rotary blade 610. Thus, the shape of the cutter unit and the scraping member is not particularly limited as long as it is a shape that slides on each face portion with a gap. The cutter unit and the scraping member are preferably plate-shaped from the viewpoint that a simple structure and processing are easy while forming a sliding surface large.

(Rotating blade shape)
Next, the shape of the rotary blades 61 and 610 used for the cutter unit of the kneading and crushing unit will be described. The shape of the rotary blades 61 and 610 is not particularly limited, and as shown in FIG. 10A, a shape having a plurality of cutting blade pieces 67 around it, a circular shape shown in FIG. It is good also as the polygonal shape shown to (C).

  By providing the cutting blade piece 67, the dewatered sludge S is caught on the cutting blade piece 67, and the dewatered sludge S can be guided into the gap. Moreover, the cutting blade piece 67 can heighten the effect | action which hooks the dewatering sludge S by setting it as the shape which inclines toward the rotation direction front. Furthermore, the effect | action which guide | induces the dewatering sludge S to a clearance gap can be heightened by setting it as the shape which inclines toward a surface part in the thickness direction of the rotary blades 61 and 610.

[Fourth embodiment]
In FIG. 11, the schematic explanatory drawing which shows the structure of the dehydration sludge conveyance system 13 of the 4th Example of this invention is illustrated.
In the dewatered sludge transport system 13 of the fourth embodiment, two cutter units 6 each having a plurality of plate-like rotary blades fixed to a rotating shaft are provided as a kneading crushing portion 51 capable of simultaneously providing a kneading action and a crushing action. The equipment provided was used. The two cutter units 6 are arranged side by side so that the rotary blades are engaged with each other, and are configured to rotate inward. Moreover, the opening part is obstruct | occluded by the obstruction | occlusion plate 65 in the upper part of the outer side of the cutter unit, and dewatering sludge S is prevented from staying outside the cutter unit 6.
The transport unit 4 has the same configuration as that of the first embodiment.

  In the kneading crushing part 51, the dewatered sludge S can be scraped off by the gaps in the surface parts of the rotary blades. Moreover, since it rotates mutually inside, the inflow to the clearance gap between the rotary blades of the dewatered sludge S can be accelerated | stimulated.

[Fifth embodiment]
In FIG. 12, the schematic explanatory drawing which shows the structure of the dewatered sludge conveyance system 14 of the 5th Example of this invention is illustrated.
In the dewatered sludge transport system 14 of the fifth embodiment, the kneading crushing section 52 of the fourth embodiment is provided with two kneading crushing sections 52 arranged in a column.
According to the kneading and crushing section 52, the agglomerated structure of the dewatered sludge S is further crushed, so that the fluidity can be maintained for a longer time.

As a configuration of the kneading and crushing section, as in the third to fifth embodiments, in addition to a device that gives an action to scrape the dewatered sludge S, two sets of screws used as the kneading section 3 of the first embodiment are used. In the kneading apparatus provided, a device in which a shearing action of the crushing portion 2 is added by projecting a plurality of cutting blades on a rotating shaft, a casing or the like may be used. Moreover, you may utilize the apparatus which provided the kneading crushing blade of the shape which has the effect | action of both shearing and kneading | mixing in the rotating shaft.
Since the dewatering sludge conveyance system provided with the kneading crushing section can be configured with a single apparatus for the kneading section and the crushing section, it exhibits an excellent effect in terms of compactness.

(Other examples of the kneading crushing part)
13 and 14 are schematic explanatory views showing the structure of the kneading crushing part of another embodiment.
The kneading and crushing section 7 shown in FIG. 13 is a device in which a plurality of cutting blades 71 are projected from a rotating shaft in a kneading device having two sets of screws. The kneading and crushing part of the present invention may be provided with a shearing action by providing a cutting blade or the like to a device for applying stress such as a known kneading device, kneader, stirrer, compressor, or pulverizer.

  Moreover, you may utilize the apparatus provided with the kneading | mixing crushing blade 81 of the shape which gives the effect | action of both a kneading effect | action and a crushing action to the dewatering sludge S like the kneading crushing part 8 shown in FIG.

  The dewatered sludge transport system of the present invention can be used to transport dewatered sludge such as a dewatered cake obtained by dewatering sludge to a predetermined facility. Moreover, since the dewatered sludge conveyance system of this invention can convey the dehydrated sludge with a low moisture content, it is utilized suitably in the incineration equipment of a dehydrated sludge.

DESCRIPTION OF SYMBOLS 1,11,12,13,14 ... Dehydrated sludge conveyance system, 2 ... Crushing part, 3 ... Kneading part, 4 ... Conveying part, 5, 51, 52 ... Kneading crushing part, 6,60 ... Cutter unit, 61,610 Rotating blade, 62 Rotating shaft, 63 Casing, 64, 640 Cutting member, 65 Blocking plate, 66 Shaft hole, 67 Cutting blade piece, 7 Kneading crushing part, 71 Cutting blade, 72 Screw , 8 ... kneading crushing part, 81 ... kneading crushing blade, S ... dehydrated sludge, W ... water, P ... solid particles, M ... motor

Claims (4)

In the dewatered sludge transport system that transports dehydrated sludge,
A dewatered sludge transport system comprising a crushing section for crushing the dehydrated sludge and a kneading section for kneading the dehydrated sludge.   The dewatering sludge conveyance system according to claim 1, wherein the crushing unit and the kneading unit include a rotary blade and a scraping member disposed in proximity to the rotary blade.   The dewatering sludge conveyance system according to claim 1 or 2, wherein the crushing unit and the kneading unit include two or more cutter units each having a plurality of rotary blades fixed to a rotation shaft. In the pretreatment method for transporting dewatered sludge,
Crushing step of crushing the dehydrated sludge;
And a kneading step for kneading the dehydrated sludge. A pretreatment method for conveying dehydrated sludge.

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