JP3840583B2 - Sludge drying equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sludge drying apparatus, and more specifically, for example, sludge drying configured to dry sludge generated in a sewage treatment process of a sewage treatment facility with a high-temperature drying gas generated in a hot air generator. It relates to the device.
[0002]
[Prior art]
Domestic sewage discharged from ordinary households, offices, department stores, restaurants, etc. is treated with sewage treatment facilities, and sludge containing a large amount of organic matter is generated in the process. After drying this sludge, it heats and carbonizes further, and using the obtained carbide | carbonized_material as a soil improvement agent, a snow melting agent, etc. is performed. A treatment apparatus for carbonizing sludge includes a drying apparatus for drying sludge having a high water content to a moisture content suitable for carbonization, and a carbonization apparatus for heating and carbonizing the dried sludge dried by the drying apparatus. I have. The drying device is composed of a hot air generating furnace and a drying furnace for heating air to a required temperature, and supplies the high-temperature drying gas generated in the hot air generating furnace to a drying furnace supplied with sludge having a high water content. Thus, the sludge is dried in the drying furnace.
[0003]
[Problems to be solved by the invention]
In the drying apparatus, since the treated gas exhausted from the drying furnace is mixed with odors generated from sludge, if this is discharged directly to the outside, the surrounding environment is contaminated and becomes a problem. For this reason, a deodorizing furnace is provided on the exhaust side of the drying furnace, and the treated gas discharged from the drying furnace is deodorized by burning in the deodorizing furnace and then discharged to the outside. In this case, since a deodorizing furnace is required as ancillary equipment, the equipment cost increases, the entire apparatus becomes large, and a large installation space is required. In addition, it is pointed out that the cost of fuel used in the deodorization furnace increases and the overall running cost increases.
[0004]
OBJECT OF THE INVENTION
The present invention has been proposed in view of the above-mentioned drawbacks inherent in the sludge drying apparatus according to the prior art, and has been proposed to suitably solve this problem. An object of the present invention is to provide a sludge drying apparatus that can reduce the amount of water.
[0005]
[Means for Solving the Problems]
To overcome the above problems and achieve an object of Tokoro phase, drying apparatus of the sludge according to the present invention,
In a drying apparatus configured to dry the sludge by supplying a high-temperature drying gas generated in a hot-air generator to a drying furnace to which sludge is supplied,
Said a hot air generator furnace outlet and drying oven inlet of communicatively connected with the supply pipe, by supplying the drying gas into the drying furnace from the hot air generator furnace through the supply pipe,
Said drying oven outlet and the inlet of the hot air generator furnace return pipe connected communication, returns the processed gas that has been cooled by the sludge and heat exchange in a drying furnace via said return to pipe the hot air generator furnace And
Insert a heat exchanger into the return pipe,
A part of the drying gas flowing through the supply pipe is introduced into the heat exchanger via a bypass pipe branched from the supply pipe and connected to the heat exchanger,
The treated gas is heat-exchanged with the drying gas by the heat exchanger and heated to a required temperature, and then returned to the hot air generating furnace .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Next, the sludge drying apparatus according to the present invention will be described in detail with reference to the accompanying drawings by giving a preferred embodiment. FIG. 1 shows a schematic configuration of a carbonization processing apparatus employing a drying apparatus according to an embodiment, in which sludge (dehydrated cake having a water content of about 80%) transported by a truck or the like from a sewage treatment facility is stored. A fixed quantity supply device 11 such as a MONO pump (registered trademark) is connected to the receiving hopper 10. This fixed amount supply device 11 is connected to a rotary kiln type drying furnace 12 constituting a drying device, and is configured to continuously supply a predetermined amount of sludge from the fixed amount supply device 11 to the drying furnace 12. As shown in FIGS. 2 and 3, the drying furnace 12 includes a charging hopper 15 having a screw conveyor 14 built in an axial end of a cylindrical rotating cylinder 13 that is rotated in a predetermined direction by a driving means (not shown). The sludge from the quantitative supply device 11 is supplied to the charging hopper 15 and then supplied to the inside of the rotary cylinder 13 via the screw conveyor 14. A plurality of lifting rods 16 are disposed on the inner wall surface of the rotating cylinder 13 so as to be spaced apart from each other in the circumferential direction. The sludge supplied to the rotating cylinder 13 is moved to the bottom side by the lifting rod 16 as the rotating cylinder 13 rotates. Then, it is moved toward the outlet 13b while repeating the process of falling to the bottom by its own weight after being lifted to the top side. In the process in which the sludge falls to the bottom, the sludge is brought into contact with a high-temperature (for example, about 700 ° C.) drying gas supplied from a hot-air generating furnace 17 described later that constitutes a drying apparatus together with the drying furnace 12. Is made.
[0007]
Inside the rotating cylinder 13, a rotating shaft 18 is rotatably disposed at a position deviated from the axial center of the rotating cylinder 13, and the rotating shaft 18 is configured to be rotated in a predetermined direction by a drive motor 19. Is done. As shown in FIG. 2, the rotary shaft 18 is provided with a plurality of crushing and stirring blades 20 that are spaced apart in the axial direction. The sludge that is lifted from the bottom side to the top side by 16 and falls to the bottom by its own weight is finely crushed. In addition, the particle size of the dry sludge obtained with the said drying furnace 12 can be arbitrarily set by changing the shape and arrangement | positioning number of the crushing stirring blade 20, and the rotation speed of the rotating shaft 18. FIG.
[0008]
The other end of a supply pipe 21 having one end connected to the drying gas outlet 17 a in the hot air generating furnace 17 is connected to the air inlet 12 a of the drying furnace 12. The hot air generating furnace 17 is supplied with LPG for a pilot burner, kerosene for a heating burner and combustion air, and heats the gas to a predetermined temperature to generate a drying gas, and supplies the high-temperature drying gas to a supply pipe 21 to supply to the drying furnace 12. One end of the first return pipe 22 is connected to the exhaust port 12 b of the drying furnace 12, and the other end of the first return pipe 22 is connected to the intake port 23 a of the dust collector 23. Further, a second return pipe 24 connected to the gas inlet 17 b in the hot air generating furnace 17 is connected to the exhaust port 23 b of the dust collector 23, and the circulation blower 25 inserted in the second return pipe 24 is rotated. Thus, the high-temperature drying gas generated in the hot air generating furnace 17 is drawn into the drying furnace 12, and the treated gas from which dust has been removed by the dust collector 23 is returned to the hot air generating furnace 17 through the inlet 17b. .
[0009]
As shown in FIG. 1, the second return pipe 24 is connected to a first heat exchanger 28 to which an exhaust gas pipe 27 through which high-temperature exhaust gas generated in a carbonization furnace 26 described later flows, and from the supply pipe 21. A second heat exchanger 30 to which the branched bypass pipe 29 is connected is inserted in series. An exhaust blower 31 is inserted on the outlet side of the second heat exchanger 30 in the bypass pipe 29, and an exhaust gas pipe 27 is connected between the second heat exchanger 30 and the exhaust blower 31. By rotating 31, a part of the drying gas flowing through the supply pipe 21 is introduced into the bypass pipe 29, and the exhaust gas generated in the carbonization furnace 26 is passed through the exhaust gas pipe 27. That is, the treated gas that has been cooled by performing heat exchange in the drying furnace 12 exchanges heat with the exhaust gas in the first heat exchanger 28 and also exchanges heat with the drying gas in the second heat exchanger 30. After the temperature is raised to the temperature, the hot air generating furnace 17 is returned. Note that the air volume of the drying gas supplied to the drying furnace 12 controls the rotation of the circulation blower 25 and the exhaust blower 31 as well as the adjustment valve 46 and the second return pipe 24 inserted in the supply pipe 21. By adjusting the inserted adjustment valve 47 and the adjustment valve 48 inserted in the bypass pipe 29, the optimum state is maintained.
[0010]
A transfer device 32 is connected to the outlet 13 b of the drying furnace 12, and dried sludge dried to a required water content (about 40%) in the drying furnace 12 is supplied to the carbonization furnace 26 by the transfer device 32. . As shown in FIG. 4, the carbonization furnace 26 includes two primary furnace bodies 34 and 34 and a secondary furnace body 35 that are in communication with each other inside a furnace body 33. 34 and the secondary furnace body 35 are configured to communicate with each other through a through hole 36. The furnace body 33 is rotatably supported by a cylindrical rotary cylinder 37 penetrating the two primary furnace bodies 34, 34, and is configured to rotate in a predetermined direction by a drive motor 38. The dried sludge transferred by the transfer device 32 is supplied through the inlet 37a. The rotary cylinder 37 is provided with a plurality of dry distillation gas supply pipes 39 communicating with the primary combustion chamber 34 a defined in the primary furnace body 34, and the dry distillation gas generated inside the rotary cylinder 37. Is ejected to the primary combustion chamber 34a. Further, a plurality of auxiliary combustion burners 40 are disposed inside the primary furnace body 34, and the rotary cylinder 37 is heated by the burners 40 so that dry distillation gas can be generated (steamed state). After the dry distillation gas is generated, the inside of the rotary cylinder 37 is held in the dry distillation state by burning the dry distillation gas ejected from the rotary cylinder 37 into the primary combustion chamber 34a. The primary furnace body 34 is supplied with pilot burner LPG and auxiliary burner kerosene, and the rotary cylinder 37 is supplied with oxygen (air) sufficient to maintain a dry distillation state. It has become. The primary furnace body 34 disposed inside the furnace body 33 does not need to be divided into two groups, but is provided with one primary furnace body over substantially the entire length in the furnace body. It may be.
[0011]
A secondary combustion chamber 35a is defined inside the secondary furnace body 35, and a secondary combustion burner 41 is disposed, and unburned gas that could not be burned in the primary combustion chamber 34a is passed through. 36 is supplied to the secondary combustion chamber 35a and combusted. The secondary combustion chamber 35a is supplied with oxygen (air) in an amount capable of completely burning the unburned gas. The high-temperature exhaust gas generated by the combustion in the secondary combustion chamber 35a is supplied to the first heat exchanger 28 via the exhaust gas pipe 27 connected to the exhaust port 33a provided in the furnace body 33. Composed. The internal pressure of the carbonization furnace 26 is controlled by controlling the rotation of the exhaust blower 31 and adjusting a regulating valve 49 inserted in the exhaust gas pipe 27.
[0012]
As shown in FIG. 5, a plurality of lifting rods 42 are arranged on the inner wall surface of the rotary cylinder 37 arranged in the carbonization furnace 26 so as to be separated from each other in the circumferential direction, and the dried sludge supplied to the rotary cylinder 37 is As the rotary cylinder 37 is rotated, it is moved from the bottom side to the top side by the lifting rod 42 and then moved toward the outlet 37b while repeating the process of dropping to the bottom by its own weight. The lifting rod 42 is not an essential requirement and can be omitted.
[0013]
[Effect of the embodiment]
Next, the action of the sludge drying apparatus according to the above-described embodiment will be described in relation to the action of the entire carbonization apparatus. High-temperature drying gas generated in the hot air generating furnace 17 constituting the drying apparatus is sucked into the drying furnace 12 through the outlet 17a, the supply pipe 21 and the intake port 12a by the operation of the circulation blower 25. Further, the sludge (for example, moisture content of 80%) continuously supplied from the quantitative supply device 11 to the drying furnace 12 is lifted from the bottom side to the top side by the lifting rod 16 by the rotation of the rotary cylinder 13, and then its own weight. In the process of falling to the bottom, it is moved toward the outlet 13b while being exposed to the drying gas. In addition, the sludge is crushed to a predetermined size by the crushing stirring blade 20 that rotates integrally with the rotation of the rotating shaft 18.
[0014]
The dried sludge dried to the required moisture content (for example, 40%) in the drying furnace 12 is supplied to the rotating cylinder 37 of the carbonization furnace 26 via the transfer device 32. The inside of the rotary cylinder 37 is in a dry distillation state by the auxiliary burner 40, and dry distillation gas is generated from the dry sludge supplied to the rotary cylinder 37, and this gas undergoes primary combustion from the dry distillation gas supply pipe 39. It is ejected into the chamber 34a. And by burning the dry distillation gas injected into the primary combustion chamber 34a, the inside of the rotary cylinder 37 is maintained in a dry distillation state, and the internal dry sludge is carbonized. Note that the auxiliary burner 40 may be turned off after the inside of the rotary cylinder 37 is maintained in the dry distillation state by the combustion of the dry distillation gas. The unburned gas that could not be combusted in the primary combustion chamber 34a is supplied to the secondary combustion chamber 35a from the through hole 36 and combusted, and high-temperature exhaust gas generated in the secondary combustion chamber 35a. The gas is supplied to the first heat exchanger 28 via the exhaust gas pipe 27. Thus, deodorization is achieved by completely burning the unburned gas that could not be burned in the primary combustion chamber 34a in the secondary combustion chamber 35a.
[0015]
That is, in the drying furnace 12, the sludge is crushed while being dried from a moisture content of 80% to 40%, and the carbonized furnace 26 is configured to carbonize the dried sludge while rotating the rotary cylinder 37, so that fine carbide is produced. can do. Moreover, it becomes possible to manufacture carbides having an arbitrary particle diameter by changing the number of rotations of the rotary shaft 18 and the like. For example, as a soil conditioner used in horticulture or the like, a material having a size of about 5 mm is suitable, and a carbide having such a particle size can be obtained without crushing in a subsequent process.
[0016]
The treated gas that has been cooled down by exchanging heat with sludge inside the drying furnace 12 is exhausted from the exhaust port 12b and supplied to the dust collector 23 through the first return pipe 22, where dust is removed. . The treated gas from which dust has been removed by the dust collector 23 is discharged to the second return pipe 24 connected to the exhaust port 23b of the dust collector 23. And, in the process of the gas passing through the first heat exchanger 28 disposed in the second return pipe 24, heat is exchanged with the high-temperature exhaust gas generated in the second combustion chamber 35a, The treated gas whose temperature has been raised is supplied to the second heat exchanger 30. The second heat exchanger 30 is supplied with a high-temperature drying gas flowing through the bypass pipe 29 branched from the supply pipe 21, so that the treated gas passing through the second heat exchanger 30 is dried. The heat exchange is further performed with the working gas, and the treated gas whose temperature has been raised is returned to the hot air generating furnace 17 through the inlet 17b. Then, the treated gas returned to the hot air generating furnace 17 is combusted and heated to a required temperature, and is reused as a drying gas.
[0017]
That is, by configuring a part of the drying gas and the treated gas that has been heated using the high-temperature exhaust gas generated in the carbonization furnace 26 to be returned to the hot air generation furnace 17, Energy saving can be achieved. The treated gas exhausted from the drying furnace 12 is mixed with odor generated from sludge, but the odor is removed by burning in the hot air generating furnace 17. Therefore, it is not necessary to provide a separate deodorization furnace on the exhaust side of the drying furnace 12, and the equipment cost can be reduced and the apparatus can be downsized. Furthermore, by combining the generation of the drying gas and the deodorization of the treated gas in the hot air generating furnace 17, the fuel cost can be reduced and the running cost can be kept low.
[0018]
In addition, although the Example demonstrated about the case where the drying apparatus which consists of a drying furnace and a hot-air generation furnace was comprised as some facilities in a carbonization processing apparatus, this application is not limited to this, Only drying of sludge. It is also possible to configure as a main purpose facility. Further, the type of the drying furnace is not limited to the rotary kiln type as in the embodiment, and various types of types can be adopted.
[0019]
【The invention's effect】
As described above, the sludge drying apparatus according to the invention of claim 1 is configured to return the gas after the heat exchange with the sludge in the drying furnace to the hot air generating furnace and burn it. After treatment, the gas can be deodorized without providing an independent deodorizing furnace. That is, it is not necessary to provide a separate deodorizing furnace on the exhaust side of the drying furnace, so that the equipment cost can be reduced and the apparatus can be downsized. Further, by combining the generation of the drying gas and the deodorization of the treated gas in the hot air generating furnace, the fuel cost can be reduced and the running cost can be kept low. Furthermore, energy can be saved in the generating furnace by returning the treated gas to the hot air generating furnace. That is, the treated gas has a required amount of heat even if heat is exchanged in the drying furnace, so that energy is saved as compared with the case where the air for normal temperature is always heated to generate the drying gas. And since it heated up using a part of drying gas, and after the process gas was comprised so that it might return to a hot-air generator, the further energy saving in a hot-air generator can be achieved.
[0020]
According to the second aspect of the present invention, the temperature is raised using the high-temperature exhaust gas generated in the carbonization furnace, and then the treated gas is returned to the hot-air generator. Therefore, further energy saving in the hot-air generator Can be achieved. According to the invention of claim 3, the sludge that is lifted from the bottom side to the top side of the rotating cylinder by the lifting rod along with the rotation of the rotating cylinder and then falls to the bottom by its own weight is crushed by the crushing stirring blade. Thus, the sludge can be crushed to a predetermined size.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a carbonization apparatus employing a drying apparatus according to a preferred embodiment of the present invention.
FIG. 2 is a longitudinal sectional front view showing a schematic configuration of a drying furnace according to an embodiment.
FIG. 3 is a longitudinal side view showing a schematic configuration of a drying furnace according to an embodiment.
FIG. 4 is a longitudinal sectional front view showing a schematic configuration of a carbonization furnace according to an embodiment.
FIG. 5 is a longitudinal side view showing a schematic configuration of a carbonization furnace according to an embodiment.
[Explanation of symbols]
12 Drying furnace 12a Intake port 12b Exhaust port
13 Rotating cylinder
16 Lifting bag
18 Axis of rotation
19 Drive motor
20 Crushing blade
17 Hot air generator 17a Outlet 17b Inlet 21 Supply pipe (pipe)
22 First return pipe (tube)
24 Second return pipe (tube)
26 Carbonization furnace
27 Exhaust gas pipe
28 1st heat exchanger ( another heat exchanger )
29 Bypass pipe
30 Second heat exchanger ( heat exchanger )

Claims (3)

In the drying apparatus configured to dry the sludge by supplying the high-temperature drying gas generated in the hot air generator (17) to the drying furnace (12) to which the sludge is supplied,
Exit (17a) and the drying oven inlet (12) and (12a) are communicatively connected with the supply pipe (21) of the hot air generator furnace (17), hot air generator furnace via the feed pipe (21) ( 17) supply drying gas from the drying furnace (12)
The drying furnace (12) at the inlet (17b) tube back and (22, 24) are communicatively connected exhaust port (12b) and a hot air generator furnace (17), via said return to pipe (22, 24) it returns the drying oven (12) is cooled by sludge heat exchange the processed gas to the hot air generator furnace (17),
A heat exchanger (30) is inserted in the return pipe (24) ,
Via a bypass pipe (29) branched from the supply pipe (21) and connected to the heat exchanger (30) , a part of the drying gas flowing through the supply pipe (21) is converted into a heat exchanger (30 introduced into),
The post-treatment gas is configured to return to the hot air generating furnace (17) after heat-exchanging with a drying gas in the heat exchanger (30) and raising the temperature to a required temperature. Sludge drying equipment. The return pipe (twenty four) In the drying oven (12) Carbonization furnace for carbonizing dry sludge dried with (26) From exhaust pipe (27) Through the carbonization furnace (26) Heat exchanger in which exhaust gas generated in (28) Is inserted into the gas after the treatment, another heat exchanger (28) The sludge drying apparatus according to claim 1, wherein heat exchange with exhaust gas is performed. The drying furnace (12) Is rotated by the driving means and has a plurality of lifting rods on the inner wall surface. (16) Rotating cylinder in which sludge is supplied (13) And this rotating cylinder (13) The drive motor is rotatably arranged (19) Rotating shaft rotated by (18) And this axis of rotation (18) A plurality of crushing and stirring blades arranged axially apart from each other (20) And the rotating cylinder (13) Lifting rod along with the rotation of (16) By the rotating cylinder (13) The sludge that is lifted from the bottom side to the top side after falling to the bottom by its own weight, (20) The sludge drying apparatus according to claim 1, wherein the sludge drying apparatus is crushed with a slag.

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