JP2004074143A - Sludge treatment method and sludge treatment equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sludge treatment equipment which can rapidly lower the moisture content of a sludge agitated and mixed with a solidifying agent. <P>SOLUTION: The sludge treatment equipment is provided with an agitating and mixing section 11 for agitating and mixing the sludge with the solidifying agent and a crushing and drying section 6 for crushing and drying the sludge by bringing hot gas into collision against the sludge agitated and mixed with the solidifying agent. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a sludge treatment method for dewatering and drying sludge such as drainage sludge and food sludge, and a sludge treatment apparatus used for carrying out the sludge treatment method.
[0002]
[Prior art]
2. Description of the Related Art As a sludge treatment apparatus for solidifying sludge, an apparatus for stirring and mixing sludge with a solidifying agent is conventionally known. When the sludge is mixed with the solidifying agent with stirring, the water content is reduced and the handling property is improved.
[0003]
In recent years, for example, drainage sludge of food factories, organic sludge such as food sludge, etc. are dewatered and dried, and then pulverized. It has been proposed to recycle it as fertilizer by mixing it with the fertilizer.
[0004]
In order to convert the raw material sludge in the form of slurry into dry sludge in the form of powder, first, a solidifying agent is mixed with the raw material sludge in a sludge treatment apparatus, and then carbon dioxide gas is blown into the raw material sludge to remove as much water as possible from the raw material sludge. Next, the sludge is sun-dried or mechanically dried, and the dried and solidified sludge is crushed into a powdery sludge (for example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent No. 2987136
[0006]
[Problems to be solved by the invention]
However, in general, it takes a certain amount of time after stirring and mixing with a solidifying agent until the water content of the sludge becomes sufficiently low, which is one of the factors that hinder improvement in the sludge treatment efficiency.
[0007]
In addition, a large amount of time is required to sufficiently dry the sludge from which water has been removed by the sludge treatment apparatus by solar drying or mechanical drying.
Furthermore, since the dried sludge solidified by sun drying or mechanical drying is solidified, it takes time to pulverize the sludge into a powder having a sufficiently small particle size that can be used in a garbage bag.
[0008]
The present invention has been made to solve the above problems, and a first object of the present invention is to provide a sludge treatment capable of rapidly reducing the water content of sludge mixed and stirred with a solidifying agent or a dehydrating agent. It is to provide a device.
[0009]
Another object of the present invention is to provide a sludge treatment method that can quickly turn into powdery dry sludge.
Further, a third object is to provide a sludge treatment apparatus used for performing the above-mentioned sludge treatment method.
[0010]
[Means for Solving the Problems]
In order to achieve the first object, according to the first aspect of the present invention, after mixing and mixing the sludge with the solidifying agent, the sludge mixed with the solidifying agent is crushed with hot gas to crush the sludge. It is characterized by drying.
[0011]
The invention according to claim 2 is characterized in that after removing a part of the water contained in the raw material sludge, the sludge is dispersed and dried by a high-temperature, high-speed airflow.
In order to achieve the second object, the invention according to claim 3 is characterized in that, in the invention according to claim 2, the dispersed and dried dry sludge is mixed with the sludge before being dispersed and dried. And
[0012]
In order to achieve the third object, the invention according to claim 4 is characterized in that a stirring and mixing means for stirring and mixing the sludge with the solidifying agent and a hot gas impinging on the sludge stirred and mixed with the solidifying agent. And a pulverizing and drying means for pulverizing and drying the sludge.
[0013]
According to a fifth aspect of the present invention, there is provided a mixing means for mixing a dewatering agent with raw sludge, and a drying means for dispersing and drying the sludge mixed with the dewatering agent by a high-temperature, high-speed airflow. And
[0014]
The invention according to claim 6 is the invention according to claim 5, further comprising a re-charging means for adding a part of the dried sludge dispersed and dried by the drying means to the sludge before the drying means is dried. It is characterized by having.
[0015]
According to a seventh aspect of the present invention, in the sixth aspect of the invention, the re-introducing means adds the dry sludge to the sludge before the mixing means mixes the dehydrating agent.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
[0017]
FIG. 1 is a schematic diagram schematically showing the entire configuration of the sludge treatment apparatus of the present embodiment. As shown in the figure, the sludge treatment device of the present embodiment is provided with a stirring and mixing unit 11. The stirring and mixing section 11 is for stirring and mixing the sludge with the solidifying agent. Here, first, the stirring and mixing section 11 will be described with reference to FIG. FIG. 2 is a front view showing the stirring and mixing unit 11 of the sludge treatment apparatus of the present embodiment.
[0018]
As shown in FIG. 2, the stirring and mixing section 11 is provided with a rotating drum 12. Sludge from a sludge hopper 13 and a solidifying agent from a solidifying agent hopper (not shown) are supplied to the rotating drum 12. Then, the sludge and the solidifying agent put into the rotary drum 12 are mixed and stirred in the rotary drum 12 driven to rotate by the motor 14. The sludge mixed and stirred with the solidifying agent is discharged from the rotary drum 12 and transferred to the pulverizing and drying unit 16 (see FIG. 1) by the conveyor 15 (transferring means). The solidifying agent used here is preferably a quick calcareous solidifying agent, that is, calcium oxide or a substance mainly composed of calcium oxide, and its addition amount is preferably 5 to 25 vol% with respect to the sludge.
[0019]
Next, returning to FIG. 1, the configuration of the sludge treatment device other than the stirring and mixing unit 11 will be described. As shown in FIG. 1, a steam jet injector 17 is connected to a pulverizing and drying unit 16 provided downstream of the stirring and mixing unit 11. The steam jet injector 17 includes a boiler 17a and an ejector 17b. The boiler 17a generates steam (hot gas), and the steam generated by the boiler 17a is sent to the pulverizing and drying unit 16 via the ejector 17b. The steam supplied from the steam jet injector 17 to the pulverizing / drying unit 16 is tangentially blown into the inside of the pulverizing / drying unit 16 which forms a cylinder, and swirls in the pulverizing / drying unit 16 to form a spiral. The sludge collides with the sludge sent from the plant and is crushed and dried. It is preferable that the speed of the steam supplied from the steam jet injector 17 to the pulverizing and drying unit 16 is equal to or greater than the Mach number 1. The speed of the steam can be increased, for example, by narrowing the cross-sectional area of the passage at the tip (injection port) of the ejector 17b to be smaller than that at the upstream side.
[0020]
In the pulverizing and drying section 16, coarse particles (sludge that is not sufficiently pulverized and dried) move toward the outer peripheral portion and fine particles (sludge that has been pulverized and dried) gather at the center due to centrifugal force generated by the steam swirling inside. It is discharged to the cyclone separator 18 along the axial flow. The cyclone separator 18 is disposed downstream of the pulverizing and drying unit 16 and separates sludge sent from the pulverizing and drying unit 16 into coarse particles and fine particles by a difference in specific gravity. The coarse particles are returned from the cyclone separator 18 to the conveyor 15 and reprocessed in the pulverizing and drying unit 16. On the other hand, the fine particles are sucked by a suction device (not shown), collected by the bag filter 19, and recovered as solidified sludge (calcium carbonate substance) sufficiently pulverized and dried. Then, the solidified sludge collected by the bag filter 19 is sent to the collection pit by the conveyor 20 (transporting means).
[0021]
The sludge treatment device of the present embodiment is provided with a control device 21. The control device 21 measures the amount of sludge sent from the crushing and drying unit 16 to the cyclone separator 18 and controls the amount of sludge sent from the stirring and mixing unit 11 to the crushing and drying unit 16. At the same time, the internal temperature and humidity of the crushing and drying unit 16 are measured, and the flow rate and temperature of steam supplied from the steam jet injector 17 to the crushing and drying unit 16 are controlled.
[0022]
The effects obtained by the present embodiment will be described below.
(1) The sludge treatment apparatus of the present embodiment is provided with a crushing and drying section 16 for crushing and drying the sludge by colliding steam (hot gas) with the sludge mixed and stirred with the solidifying agent. Therefore, the water content of the sludge mixed and stirred with the solidifying agent can be rapidly reduced, and the sludge treatment efficiency can be improved.
[0023]
Incidentally, when sludge having a water content of 80% is treated by the sludge treatment apparatus of the present embodiment, the sludge which has been stirred and mixed with the solidifying agent in the stirring and mixing section 11 to have a water content of about 70% is crushed and dried. At 16, the water content drops to around 10% in about one hour. On the other hand, when sludge having a water content of 80% is treated by a conventional sludge treatment device having no crushing and drying section 16, it takes about 168 hours to obtain solidified sludge having a water content of about 10%.
[0024]
(2) According to the sludge treatment apparatus of the present embodiment, the sludge mixed and stirred with the solidifying agent can be crushed simultaneously with drying, so that the soil improving material and the special fertilizer can be used without being crushed again using a crusher. It can be provided as a material.
[0025]
(3) Since the sludge treatment apparatus of the present embodiment returns coarse particles from the cyclone separator 18 to the conveyor 15 and reprocesses them in the crushing and drying unit 16, it is possible to convert all sludge into required fine powder. it can.
[0026]
(2nd Embodiment)
Next, a second embodiment in which the present invention is embodied in a sludge treatment plant will be described with reference to FIGS.
[0027]
As shown in FIGS. 3 and 4, the sludge treatment plant 30 includes a kneader 31, a blower 32, a heater 33, a hot-air transport type dryer 34, a first bag filter 35, a temporary storage tank 36, a return pressure sending pipe 37, a blower 38, a classifier 39, a first product tank 40, a second bag filter 41, a second product tank 42, and the like.
[0028]
In the sludge treatment plant 30, first, a dehydrating agent (for example, quicklime) and a powdery dry sludge are added to the slurry raw sludge, and these are mixed by the kneader 31. In this process, the moisture of the raw material sludge is chemically reacted with the dehydrating agent to remove a part of the moisture, and the dried sludge is mixed with the powdered sludge to obtain a dehydrated sludge having a reduced moisture content. Furthermore, the dewatered sludge is made into a gravel state by kneading. The dried sludge in powder form is obtained by dewatering and drying in the present sludge treatment plant 30. In the present embodiment, the kneading machine 31 is a mixing unit.
[0029]
Next, the gravel-like dewatered sludge is flash-dried by a hot-air conveying dryer (hereinafter simply referred to as a dryer) 34 using a high-temperature and high-speed air flow supplied from a blower 32 and a heater 33. By this process, the gravel-like dewatered sludge is dispersed and dried to make powdery dry sludge. In the present embodiment, the blower 32, the heater 33, and the dryer 34 constitute a drying unit.
[0030]
Next, the dried sludge is collected by the first bag filter 35 and stored in the temporary storage tank 36. Then, a part of the dried sludge stored in the temporary storage tank 36 is pneumatically conveyed by the return pressure feed pipe 37 and the blower 38 and added to the raw sludge to be fed into the kneader 31. In the present embodiment, the temporary storage tank 36, the return pressure feed pipe 37, and the blower 38 constitute a re-charging unit.
[0031]
On the other hand, the dried sludge in the temporary storage tank 36 is separated into coarse particles and fine particles by the classifier 39, and the dried sludge of coarse particles is stored in the first product tank 40.
Further, the fine sludge dried sludge is conveyed from the classifier 39 to the second bag filter 41, collected from the airflow by the second bag filter 41, and stored in the second product tank 42.
[0032]
That is, in this sludge treatment plant, the raw material sludge in the form of slurry is dried into powder, and this is commercialized as dried sludge divided into coarse particles and fine particles. Of these, dried sludge of fine particles is used for garbage bags.
[0033]
Next, the sludge treatment plant 30 will be described in detail.
In the kneader 31, raw sludge directly loaded from the outside of the plant or raw sludge dehydrated to a certain extent by a filter press is continuously fed by a screw conveyor 44 from an intermediate storage hopper 43 for temporarily storing the sludge. Supplied. The water content of the raw sludge is 80 to 95 wt%.
[0034]
To the raw sludge supplied to the kneader 31, a dehydrating agent for removing a part of the water content of the raw sludge and a dry sludge dried into a powder are added at a predetermined mixing ratio.
[0035]
The dehydrating agent is conveyed from the dehydrating agent hopper 45 by the screw conveyor 46 and is added to the raw sludge from the middle of the screw conveyor 44.
In addition, dry sludge dewatered and dried in the present sludge treatment plant 30 is added to the raw sludge at a predetermined ratio. The dried sludge is pneumatically conveyed from the temporary storage tank 36 in which the dried sludge that has been subjected to the drying processing is temporarily stored by the air flow generated by the blower 38 through the return pressure pipe 37. The transported dry sludge is added to the raw sludge to which the dehydrating agent has been added in the middle of the screw conveyor 44.
[0036]
The kneading machine 31 includes a rotary drum 31a, and mixes the raw sludge, the dried sludge, and the dehydrating agent continuously fed from the inlet thereof. Then, the water is removed from the raw sludge by the action of the dehydrating agent. For example, when quicklime is used as the dehydrating agent, the water in the raw sludge is reacted with calcium carbonate to form calcium hydroxide, thereby reducing the water in the raw sludge and the heat of reaction at that time. This causes water to evaporate from the raw sludge.
[0037]
The water vapor generated in the rotating drum 31a is sucked into the blower 48 through the deodorizing cover 47 provided on the discharge port side of the rotating drum 31a, and is discharged from the deodorizing tower 49 into the outside air.
[0038]
The kneading machine 31 also lowers the water content of the entire mixed sludge by mixing the raw sludge with the dry sludge.
By the dewatering and kneading in the kneading machine 31, the raw material sludge is discharged as dehydrated sludge solidified in a gravel state. The water content of the dewatered sludge is 35 to 40 wt%. In the present embodiment, a larger amount of the dewatering agent than the mixing ratio required in the kneading machine 31 is added to the raw material sludge so that the dewatered sludge contains a certain amount of the dewatering agent that has not reacted with water. . This is because the unreacted dehydrating agent is reacted in the dryer 34.
[0039]
The kneader 31 mixes the raw sludge, the dried sludge and the quicklime while moving the mixture to the outlet side thereof, and continuously supplies the raw sludge to the dryer 34 from an outlet chute 31b connected to the outlet. At this time, the supply amount is adjusted by the rotary valve 50.
[0040]
The high-temperature and high-speed air generated by the blower 32 and the heater 33 is continuously supplied to the dryer 34. The blower 32 is a turbo fan, and the heater 33 is an LPG gas burner. Further, air is continuously sucked from the dryer 34 by the blower 51 through the first bag filter 35. This blower 51 is a roots blower. That is, the dryer 34 is continuously supplied with an amount of air set by the amount of air supplied by the blower 32 and the heater 33 and the amount of air discharged by the blower 51.
[0041]
The dryer 34 continuously flash-drys the gravel-like dewatered sludge supplied from the kneader 31 by a high-temperature, high-speed air flow. Then, the dewatered sludge is dispersed and dried to form a powdery dry sludge. The moisture content of the dried sludge is about 10% by weight.
[0042]
The dryer 34 is manufactured by Seishin Enterprise Co., Ltd. (trade name: Flash Jet Dryer), and has an upright annular main body portion 34a, in which dehydrated sludge and air are circulated. An annular airflow drying passage is provided. The main body has an inlet for introducing dewatered sludge into the flash drying passage, a supply port for introducing high-temperature, high-speed air into the flash drying passage, and an air flow for drying and drying powdery dispersed and dried sludge. An outlet is provided for discharging air from the drying passage together with air.
[0043]
The dewatered sludge introduced into the airflow passage of the main body 34a from the inlet is blown off in the airflow passage by high-temperature, high-speed air introduced into the airflow passage from the supply opening, and is rapidly dispersed and dried. At this time, the high-temperature, high-speed air collides with the large sludge particles of the dewatered sludge, whereby the sludge is broken into a plurality of small sludge particles, and the water contained therein evaporates rapidly. In addition, the water contained therein reacts with the dehydrating agent that has not reacted in the kneading machine 31, thereby promoting dehydration from the dewatered sludge.
[0044]
Then, the sludge particles dispersed and dried to a particle size smaller than a certain level are discharged as dry sludge to the outside from the discharge port through the discharge port by air from the discharge port. On the other hand, sludge particles having an insufficient degree of dispersion and drying and having a relatively large particle size are not discharged from the discharge port, and circulate again in the air flow passage until they are sufficiently dispersed and dried. Therefore, the dryer 34 discharges only the sufficiently dispersed and dried powdery sludge as dry sludge.
[0045]
The dried sludge that has been dispersed and dried by the drier 34 is pneumatically conveyed to the first bag filter 35 by an airflow flowing in the main body 34a.
The first bag filter 35 continuously collects powdery dried sludge conveyed from the dryer 34 by air.
[0046]
The dried sludge collected by the first bag filter 35 is continuously conveyed to the temporary storage tank 36 by the screw conveyor 53 while the conveyance amount is adjusted by the rotary valve 52.
[0047]
The temporary storage tank 36 stores the dried sludge transported from the first bag filter 35.
A part of the sludge stored in the temporary storage tank 36 passes through a return pressure feed pipe 37 that connects the temporary storage tank 36 and the screw conveyor 44, and is generated by an airflow generated by a blower 38 provided on the return pressure feed pipe 37. It is conveyed by air and added to the raw sludge before being put into the kneader 31. The blower 38 is a roots blower.
[0048]
At this time, the amount of dry sludge added to the raw sludge is adjusted by a rotary valve 54 provided between the temporary storage tank 36 and the blower 38.
The dried sludge stored in the temporary storage tank 36 is separated by the airflow generated by the blower 55 provided on the pipe connecting the second bag filter 41 and the deodorization tower 49 with the classifier 39 and the second bag filter. The air is sucked through 41 and continuously conveyed to the classifier 39 by air. At this time, the transport amount is adjusted by a rotary valve 56 provided between the temporary storage tank 36 and the classifier 39.
[0049]
The classifier 39 is a cyclone filter, and collects coarse particles from the powdery dry sludge conveyed from the temporary storage tank 36 by air.
The dried sludge of coarse particles collected by the classifier 39 is sent to and stored in the first product tank 40 with the transport amount adjusted by the rotary valve 57.
[0050]
On the other hand, the dried sludge of fine particles not collected by the classifier 39 is air-conveyed to the second bag filter 41 by the airflow generated by the blower 55.
The second bag filter 41 continuously collects fine particles of the dried sludge conveyed from the classifier 39 by air.
[0051]
The dried sludge of the fine particles collected by the second bag filter 41 is sent to and stored in the second product tank 42 with the transport amount adjusted by the rotary valve 58.
The air after the dried sludge is collected by the second bag filter 41 is discharged from the deodorization tower 49 into the outside air.
[0052]
Next, the operation of the present embodiment configured as described above will be described.
The slurry raw material sludge introduced into the kneader 31 removes a part of its water content by mixing a dehydration treatment agent, and its moisture content is reduced by mixing dry dried sludge. Then, by being kneaded, dehydrated sludge solidified in a gravel state is obtained.
[0053]
In the present embodiment, when sludge having a water content of 80 to 85 wt% is introduced into the kneading machine 31, the water content of the dewatered sludge becomes 35 to 40 wt%. On the other hand, when only the dewatering agent was added without adding the dried sludge, the water content was 65 to 70 wt%.
[0054]
The dewatered sludge supplied to the dryer 34 is dispersed by the high-temperature and high-speed air flow supplied from the heater 33, and is rapidly dried to dry powder sludge.
In the present embodiment, the moisture content of the dried sludge is about 10 vol%. And, from the dewatered sludge having a water content of 35 to 40 wt%, dry sludge having a water content of about 10 wt% can be continuously generated.
[0055]
On the other hand, in order to continuously produce the same amount of dry sludge from cake-like sludge having a water content of 65 to 70%, a dryer 34 having a much larger processing capacity is used and supplied from the heater 33. The amount of high-temperature and high-speed air needed to be much larger.
[0056]
In addition, when the dry sludge was added at the following ratio to the case where dry sludge was not added to the raw material sludge, the throughput per unit time was larger.
a. When the weight ratio between the raw sludge and the dry sludge is in the range of 5:95 to 95: 5, the throughput per unit time is larger than when the dry sludge is not added to the raw sludge.
[0057]
b. When the weight ratio between the raw sludge and the dried sludge is in the range of 25:75 to 75:25, the throughput per unit time is further increased as compared with the case of a.
c. When the weight ratio of the raw sludge to the dried sludge is in the range of 40:60 to 60:40, the throughput per unit time is the largest.
[0058]
In addition, the average particle size of the dried sludge generated in the present embodiment was about 1 to 20 μm. On the other hand, the average particle size of the dried sludge generated from the sludge having a water content of 65 to 70 wt% was about 100 μm.
[0059]
Next, the effects of the present embodiment described in detail above will be listed.
(4) The dewatered sludge generated by mixing the raw material sludge with the dewatering treatment agent in the kneader 31 is dispersed and dried in the dryer 34 using the high-temperature and high-speed air flow generated by the blower 32 and the heater 33.
[0060]
Therefore, the dewatered sludge can be dried more quickly than when it is dried by solar drying or the like. Further, since the dispersion and the drying are performed at the same time, the sludge is not solidified by the drying, unlike the case of drying in the sun. Therefore, it is not necessary to pulverize the solidified dry sludge with a pulverizer, so that powdery dry sludge can be obtained more quickly.
[0061]
(5) The powdery dry sludge dispersed and dried by the dryer 34 is added to the raw sludge and mixed by the kneader 31 to obtain a gravel-like dehydrated sludge having a water content of 35 to 40 wt%. The dewatered sludge is dispersed and dried by the dryer 34 to obtain powdery dried sludge.
[0062]
For this reason, since the dryer 34 can efficiently disperse and dry the gravel-like dewatered sludge, the amount of dry sludge generated per unit time is larger than when the dry sludge is not added to the raw material sludge. More.
[0063]
Therefore, it is possible to use the dryer 34 having a smaller processing capacity and to further reduce energy consumption for generating high-temperature and high-pressure air. As a result, the equipment cost can be lower and the running cost can be lower.
[0064]
(6) Since a part of the dried sludge dried by the dryer 34 is returned to the raw material sludge and dispersed and dried again as dewatered sludge, the average particle size of the dried sludge is smaller than in the case where the dried sludge is not returned. Become.
[0065]
Therefore, when dry sludge is mixed in a sheet material for making a garbage bag, sludge particles do not fall off the sheet material, and a higher quality garbage bag can be obtained.
Next, embodiments other than the first and second embodiments will be listed.
[0066]
In the first embodiment, the sludge mixed and stirred with the solidifying agent is caused to collide with steam as a hot gas to pulverize and dry the sludge. However, instead of steam, heated air, heated nitrogen gas, or steam is used. A hot gas other than steam, such as a mixed gas of air and heated air, may be used. When a mixed gas of steam and heated air is used instead of steam, the temperature of the hot gas supplied to the crushing and drying unit 16 can be easily increased, and the drying efficiency can be improved.
[0067]
-In the said 1st Embodiment, in order to insulate the inside and the outside of the pulverization drying part 16, the pulverization drying part 16 may be made into a double wall structure. In this way, the drying efficiency in the crushing and drying section 16 can be increased.
[0068]
In the first embodiment, as the stirring and mixing means, a mortar mixer-type stirring and mixing in which a fixed amount of the raw material sludge is stirred and mixed with the dehydrating agent instead of the continuous stirring and mixing section 11 having the rotary drum 12. It may be a unit. In this case, even when treating a small amount of raw material sludge, the mixing ratio with the dewatering agent can be set accurately, so that, for example, waste of the dewatering agent is eliminated, or the water content of the raw material sludge is reduced. It can be reliably reduced to a predetermined value.
[0069]
In the second embodiment, the powdery sludge may be added to the slurry raw sludge before the dewatering agent.
In the second embodiment, the heater that generates high-temperature and high-speed air to be supplied to the dryer is not limited to the LPG heater, and may be a heater using energy other than LPG as a heat source, such as a heavy oil heater, a steam heater, and an electric heater. There may be.
[0070]
In the second embodiment, the dewatered sludge dewatered by the filter press may be directly dispersed and dried by the dryer 34 without using the kneader 31. This configuration also has the effects described in (4) to (6) of the second embodiment.
[0071]
-In 2nd Embodiment, it is good also as a structure which supplies carbon dioxide gas to the kneading machine 31, and makes the water | moisture content evaporate from raw sludge by the heat | fever generated by making it react with calcium oxide of a dehydration treatment agent. In this case, since the dewatered sludge having a lower moisture content can be supplied to the dryer 34, a sludge having a smaller treatment capacity can be used, and energy consumption for generating high-temperature and high-pressure air can be reduced. Can be reduced.
[0072]
In the second embodiment, a configuration may be adopted in which dry air is supplied to the kneader 31 and steam generated by the reaction heat between the moisture of the raw sludge and the dehydrating agent is forcibly discharged from the kneader 31. In this case, dewatered sludge having a lower moisture content can be supplied to the dryer 34.
[0073]
In the second embodiment, a coarse particle may be collected by the classifier 39 from all of the dried sludge collected by the first bag filter 35, and a part of the coarse particle may be added to the raw sludge. . In this case, the dried sludge of coarse particles is again dispersed and dried by the dryer 34, and a part of the dried sludge becomes fine particles, so that the yield of dry sludge of fine particles increases.
[0074]
In the second embodiment, a part of the high-temperature (for example, about 100 ° C.) airflow discharged from the first bag filter 35 may be returned to the high-temperature airflow supplied by the heater 33. In this case, since a part of the energy can be recovered from the high-temperature air stream discharged from the dryer 34, for example, the gas consumption of the heater 33 can be reduced, and thus the entire sludge treatment plant 30 can be reduced. Energy consumption can be reduced.
[0075]
In the second embodiment, two kneading machines are provided, and the first kneading machine mixes a dewatering agent with the slurry raw sludge to remove a part of water, and the second kneading is performed on the sludge. It is good also as composition which mixes powdery dry sludge with a machine and lowers a moisture content. According to such a configuration, in the first kneader, the reaction between the water in the raw material sludge and the dehydrating agent can be promoted. For example, it is possible to eliminate the unreacted and wasteful dehydrating agent. it can.
[0076]
In the second embodiment, the sludge treated by the kneader was supplied to two dryers, and all of the dewatered sludge treated by the first dryer was mixed with the raw sludge and treated by the second dryer. All of the dewatered sludge may be sent to the classifier 39.
[0077]
Hereinafter, technical ideas grasped from the above embodiments will be listed.
(1) The sludge treatment apparatus according to claim 4, further comprising means for returning coarse particles of the sludge after being crushed and dried by the crushing and drying means to the crushing and drying means. In this way, all the sludge can be made into the required fine powder.
[0078]
(2) The treatment of crushing and drying the sludge in the crushing and drying means by colliding a hot gas with the solidifying agent and stirring and mixing the sludge is performed in a system in which the inside and outside are insulated. 5. The sludge treatment device according to 4. By doing so, the drying efficiency of the pulverizing and drying means can be increased.
[0079]
(3) The sludge treatment apparatus according to claim 4, wherein the hot gas is a mixed gas of steam and heated air. With this configuration, the temperature of the hot gas can be easily increased, and the drying efficiency of the pulverizing and drying unit can be improved.
[0080]
(4) The sludge treatment method according to claim 3, wherein the dispersed and dried dry sludge is mixed with the raw material sludge.
(5) The sludge treatment method according to (4), wherein the raw material sludge and the dried sludge are mixed so that the weight ratio is in the range of 5:95 to 95: 5. In this case, the amount of sludge that can be dried per unit time is larger than when not adding sludge to the raw sludge.
[0081]
(6) The sludge treatment method according to (4), wherein the raw material sludge and the dried sludge are mixed so that the weight ratio thereof is in the range of 25:75 to 75:25. In this case, the amount of sludge that can be dried per unit time is further increased.
[0082]
(7) The sludge treatment method according to (4), wherein the raw sludge and the dried sludge are mixed so that a weight ratio thereof is in a range of 40:60 to 60:40. In this case, the amount of sludge that can be dried per unit time is the largest.
[0083]
(8) The sludge treatment apparatus according to claim 6 or 7, wherein the re-injection unit conveys the dried sludge by air and adds the dried sludge to the sludge before the drying unit is dried. According to such a configuration, powdery sludge can be continuously added.
[0084]
【The invention's effect】
According to the first to seventh aspects of the present invention, the water content of sludge mixed and stirred with a solidifying agent or a dehydrating agent can be rapidly reduced.
[0085]
According to the third, sixth, and seventh aspects of the present invention, it is possible to quickly turn into powdery dry sludge.
[Brief description of the drawings]
FIG. 1 is a schematic diagram schematically showing the entire configuration of a sludge treatment apparatus according to a first embodiment.
FIG. 2 is a front view showing a stirring and mixing section of the sludge treatment apparatus.
FIG. 3 is a schematic diagram showing a main part of a sludge treatment device according to a second embodiment.
FIG. 4 is a schematic view showing a part of a sludge treatment device.
[Explanation of symbols]
11: stirring and mixing unit as stirring and mixing means, 16: pulverizing and drying unit as pulverizing and drying means, 30: sludge treatment plant, 31: kneader as mixing means, 32: blower as drying means, 33: heater, Reference numeral 34 denotes a hot-air transfer type dryer, 36 denotes a temporary storage tank as a re-injecting means, 37 denotes a return pressure feed pipe, and 38 denotes a blower.

Claims (7)

A method for treating sludge, comprising mixing and mixing sludge with a solidifying agent, and then colliding the sludge mixed with the solidifying agent with hot gas to pulverize and dry the sludge. A method for treating sludge, comprising removing a part of water contained in raw material sludge, and then dispersing and drying the sludge with a high-temperature, high-speed airflow. The sludge treatment method according to claim 2, wherein the dispersed and dried dried sludge is mixed with the sludge before being dispersed and dried. A sludge comprising stirring and mixing means for stirring and mixing sludge with a solidifying agent, and crushing and drying means for crushing and drying the sludge by colliding hot gas with the sludge mixed and stirred with the solidifying agent. Processing equipment. Mixing means for mixing the dewatering agent with the raw sludge,
A sludge treatment apparatus comprising: drying means for dispersing and drying sludge mixed with a dehydrating agent by a high-temperature, high-speed airflow. The sludge treatment apparatus according to claim 5, further comprising: a re-injection unit that adds a part of the dried sludge dispersed and dried by the drying unit to the sludge before the drying unit is dried. The sludge treatment apparatus according to claim 6, wherein the recharging unit adds the dried sludge to the sludge before the mixing unit mixes the dewatering agent.

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