JP2005037096A - Reduced-pressure drying device and method, and carbonization treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduced-pressure drying device capable of realizing the drying operation of high efficiency while miniaturizing a device for drying a raw material, as a pre-processing for carbonizing the raw material such as a sludge cake, a reduced-pressure drying method, and a carbonization treatment device comprising the same. <P>SOLUTION: In the reduced-pressure drying device for drying the raw material under reduced-pressure as a pre-stage of carbonizing the raw material such as the sludge cake, the sludge is forcedly fed by a snake pump 4, and continuously conveyed, while sealing an opening at one end, of each of drying containers 7, 8 by the force-fed sludge. When the sludge is introduced into the drying containers 7, 8, the sludge is shaped into a plurality of cords by a cord-like cake shaper. Then the sludge is heated while being conveyed in the drying containers 7, 8 decompressed in advance, whereby the percentage of water content of the sludge is lowered to approximately 40 %. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is applied, for example, as a pre-process when carbonizing raw materials such as activated sludge dehydrated cake (hereinafter simply referred to as sludge cake) generated in a water treatment system, coffee beans, tea leaves, etc. The present invention relates to an apparatus and method for drying, and a carbonization apparatus equipped with the vacuum drying apparatus. In particular, the present invention relates to a measure for realizing a highly efficient vacuum drying operation with a small apparatus.

  Conventionally, a sludge cake obtained by dewatering concentrated sludge in a water treatment system has a moisture content of 70% or more, has a large volume, and requires a lot of labor and cost for transportation.

  Therefore, generally, this sludge cake is heated and carbonized. As a result, the volume is reduced to about 1/10 to 1/20 to facilitate subsequent processing (transportation, etc.), or the obtained carbide is used as a soil conditioner, deodorant, dehydration aid, fuel, Efficient use as materials is carried out.

  However, since this sludge cake before carbonization has high adhesiveness, even if it is to be transported by the screw conveyor provided in the transport path, it adheres to the screw or the pipe wall of the transport path by its adhesive force. As a result, good conveyance could not be performed.

  For this reason, for example, as disclosed in Patent Document 1 below, first, a sludge cake is supplied to a drying device, and the sludge cake is heated and dried in the drying device. As a result, the sludge cake has a moisture content of about 40% and can be easily transported.

Then, the sludge cake thus dried is taken out from the drying device and supplied to the carbonization device (carbonization carbonization furnace), and the sludge cake is heated in an oxygen-free state in the carbonization device. Carbonize. Thus, the sludge cake was carbonized by a two-stage process using individual devices.
Japanese Patent Laid-Open No. 11-60223

  However, in the method of performing the carbonization treatment using the drying apparatus and the carbonization apparatus, since it is necessary to install each apparatus individually, there is a problem that an increase in the size of the entire system cannot be avoided. In addition, since a predetermined amount of sludge cake is put inside the drying apparatus and the drying process is performed, the so-called batch processing is performed in which the sludge cake is taken out from the drying apparatus, so that the processing time can be shortened. There was a limit.

  In view of this point, a carbonization apparatus in which a drying processing unit and a carbonization processing unit are provided in a single furnace is configured, and before the sludge cake is put into the carbonization device, the already generated charcoal powder is mixed. By forming a charcoal adhesion layer on the surface of the sludge cake, clogging of the sludge cake in the conveyance path is prevented.

  However, in this method, the mixing process of the sludge cake and powdered coal becomes complicated, leading to an increase in the manufacturing cost of the apparatus, or the fine powder of charcoal burns due to the trace amount of oxygen remaining in the carbonization process. There is a drawback that ash is mixed with the carbonized product. Moreover, the carbide | carbonized_material produced | generated by this apparatus becomes a mixture of a granular thing and the thing of a fine powder form, and there exists a disadvantageous surface in the effective utilization of a product.

  This problem is not limited to carbonization of sludge cake, but carbonization of various wastes such as coffee beans, tea leaves, barns and stables, chicken manure, rice husks, vegetable waste, and grass. This also occurs in some cases.

  The present invention has been made in view of the above points, and the object of the present invention is to achieve high efficiency while reducing the size of the apparatus for drying the raw material as a pre-process for carbonizing the raw material such as sludge cake. Another object of the present invention is to provide a reduced-pressure drying apparatus, a reduced-pressure drying method, and a carbonization apparatus equipped with the reduced-pressure drying apparatus that realize a proper drying operation.

-Summary of invention-
In order to achieve the above object, the present invention provides, for example, a predetermined dry state by heating the raw material while transporting the raw material in a decompressed space when the raw material such as sludge cake is used as a pre-stage for carbonization. Is to be obtained. Thereby, it is possible to perform the drying process with high efficiency even in a small apparatus as compared with a conventional apparatus for drying a raw material by batch processing.

-Solution-
Specifically, the present invention is premised on a reduced-pressure drying apparatus that performs a drying treatment of a water-containing raw material. This vacuum drying apparatus is provided with a vacuum container, a vacuum unit, a raw material charging unit, a conveying unit, and a raw material outlet unit. The decompression container has a raw material inlet and a raw material outlet. The decompression means is for bringing the internal space of the decompression container into a decompressed state. The raw material charging means is for charging the raw material while sealing the raw material inlet with the raw material by continuously charging the raw material when the raw material is charged into the vacuum container from the raw material inlet. The conveying means gradually dries the water-containing raw material while conveying the raw material from the raw material inlet to the raw material outlet in the internal space of the decompression vessel. The raw material deriving means derives the raw material from the raw material discharge port of the decompression container while preventing the internal space of the decompression vessel from being released into the atmosphere from the raw material discharge port.

  According to this specific matter, first, the internal space of the decompression container is brought into a decompressed state by the decompression means. In this state, a water-containing raw material (for example, sludge having a water content of about 70%) is introduced toward the raw material inlet of the decompression vessel by the raw material charging means. At this time, since the water-containing raw material is continuously charged into the decompression vessel, the raw material itself serves to seal the raw material introduction port, and the internal space of the decompression vessel is not opened to the atmosphere from the raw material introduction port. . The hydrated raw material that has been continuously charged is conveyed toward the raw material discharge port by the conveying means. At this time, since it passes through the internal space of the depressurized container in a depressurized state, the moisture content contained in the raw material is reduced. The boiling point decreases, and a large amount of moisture is released from the raw material during this conveyance. As a result, the moisture content of the raw material is significantly reduced, for example, reaching a moisture content of about 40%. The raw material thus dried is derived from the raw material outlet of the decompression vessel by the raw material deriving means, and is transferred to, for example, the next carbonization step. The above operation is performed by a vacuum drying apparatus. Since the water-containing raw material is dried while being transported in this manner, it is possible to realize a highly efficient drying operation while reducing the size of the apparatus as compared with the conventional batch-type drying apparatus. That is, in the conventional batch-type drying apparatus, a predetermined amount of water-containing raw material is put into the drying apparatus, and after performing the drying process, it is necessary to take out the raw material from the drying apparatus. There was a limit to shortening the time. According to the present invention, it is possible to continuously feed and continuously feed raw materials while maintaining the internal space of the vacuum vessel in a reduced pressure state, and greatly increase the amount of raw materials that can be processed per unit time. be able to.

  In addition, the following is mentioned as a structure of the reduced pressure drying apparatus which can acquire the said effect | action without providing the said conveying means. That is, it is premised on a reduced-pressure drying apparatus that performs a drying process of the water-containing raw material. This vacuum drying apparatus is provided with a vacuum container, a vacuum means, a raw material charging means, and a raw material outlet means. The decompression container has a raw material inlet and a raw material outlet. The decompression means is for bringing the internal space of the decompression container into a decompressed state. The raw material charging means is for charging the raw material while sealing the raw material inlet with the raw material by continuously charging the raw material when the raw material is charged into the vacuum container from the raw material inlet. The raw material deriving means derives the raw material from the raw material discharge port of the decompression container while preventing the internal space of the decompression vessel from being released into the atmosphere from the raw material discharge port.

  Further, as a configuration for performing the drying operation in the internal space of the decompression vessel with high efficiency, more specifically, a heating unit for heating the raw material in the interior space of the decompression vessel is provided. As described above, since the boiling point of moisture contained in the raw material is reduced in the internal space of the decompression vessel, the moisture content of the raw material can be significantly reduced even with a heat source having a relatively low temperature. This is possible, and the running cost can be reduced.

  Moreover, the following are mentioned as a structure for drying a water-containing raw material more effectively. That is, it is the structure provided with the preheating means which heats a water-containing raw material prior to throwing a raw material into the inside of a pressure reduction container from a raw material inlet.

  According to this, at the same time that the raw material is introduced into the vacuum container from the raw material inlet, a large amount of moisture is released from the raw material, and early drying of the raw material can be realized. For this reason, the conveyance time in the conveyance means can be shortened, and the raw material can be dried with high efficiency.

  Furthermore, the following is mentioned as a structure which shape | molds the raw material thrown into the inside of a pressure reduction container in a certain shape. That is, it is provided with a string-shaped material forming means for forming a material charged into the decompression container from the material introduction port into a string shape extending along the charging direction.

  If the raw material is formed into a string shape by the string-shaped raw material forming means in this way, the surface area of the raw material can be increased, and the raw material can be dried more quickly. Moreover, since the raw material dried in the form of string is easily cut into a particulate dry raw material, the charcoal obtained after carbonization is granular. This granular charcoal is easy to transport and can be applied to various uses. In other words, according to the present solution, without requiring a special molding operation to form the charcoal obtained by carbonization into a granular form, the water-containing raw material is simply put into a vacuum vessel inside a string, It is possible to form an optimally shaped charcoal.

  Examples of the configuration for more effectively drying the water-containing raw material by discharging the moisture (water vapor) released from the water-containing raw material from the decompression vessel include the following. That is, an air injection means for injecting air into the internal space of the decompression vessel is provided. The air injection means is provided in the vicinity of the raw material introduction port in the decompression container, while the decompression means is provided in the vicinity of the raw material discharge port in the decompression container.

  According to this, when air is injected from the air injection means into the internal space of the decompression container, the air flows at a high speed toward the decompression means while expanding. The water vapor in the decompression vessel also flows toward the decompression means along the high-speed air flow, whereby the water vapor remaining in the decompression vessel is quickly discharged from the decompression vessel. Thereby, the quantity of the water | moisture content which retains in a pressure-reduced container falls significantly, and the drying of a water-containing raw material can be accelerated | stimulated significantly. Further, in the present solution, if dry air is used as the air to be injected, the effect can be further enhanced.

  Moreover, the carbonization processing apparatus provided with the reduced pressure drying apparatus which concerns on each solution means mentioned above is also the category of the technical idea of this invention. That is, a carbonization treatment apparatus for carbonizing a water-containing raw material by heating, and the reduced-pressure drying apparatus according to any one of the above-described solving means and the raw material dried by the reduced-pressure drying apparatus are input. And a carbonizing furnace for carbonizing the raw material by heating.

  Further, the reduced pressure drying method executed by the reduced pressure drying apparatus according to each of the above-described solutions is also within the scope of the technical idea of the present invention. In other words, the raw material is continuously introduced into the vacuum vessel while the raw material inlet of the vacuum vessel whose internal space is previously maintained in a reduced pressure state is sealed with the raw material, and the water-containing raw material that has been continuously added is decompressed. This is a reduced-pressure drying method in which drying is performed while being transported by a transport means in a container.

  As another method, the raw material is continuously introduced into the reduced pressure vessel while the raw material inlet of the reduced pressure vessel whose internal space is previously maintained in a reduced pressure state is sealed with the raw material. There is also a vacuum drying method in which the water-containing raw material is gradually dried while being stirred in a vacuum container.

  In the present invention, a predetermined dry state is obtained by heating a raw material such as a sludge cake in a decompressed space. In particular, it is possible to continuously feed raw materials while maintaining the decompressed state inside the vacuum vessel by continuously feeding the water-containing raw material inside the vacuum vessel and sealing the raw material inlet. I have to. As a result, it is possible to perform the drying process with high efficiency even with a small apparatus, compared to the conventional batch process for drying the raw material, and greatly increase the amount of raw material that can be processed per unit time. be able to.

  In addition, since the raw material introduced into the vacuum vessel from the raw material inlet is formed in a string shape extending along the direction of introduction, the surface area of the raw material can be increased and the raw material can be dried more quickly. It is possible to make it. In addition, since the raw material dried in a string form is easily cut into a particulate dry raw material, the charcoal obtained after the carbonization treatment becomes granular. This granular charcoal is easy to transport and can be applied to various applications, and it has the optimum shape without requiring special molding operation to form charcoal obtained by carbonization into granular form. It becomes possible to mold the charcoal.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This invention demonstrates the case where this invention is applied to the carbonization processing apparatus for carbonizing the sludge cake obtained by dehydrating concentrated sludge in a water treatment system.

  FIG. 1 is a diagram showing a schematic configuration of a carbonization apparatus 1 according to the present embodiment. As shown in FIG. 1, a carbonization treatment apparatus 1 according to this embodiment includes a reduced pressure drying apparatus 2 and a hot stove 3 as a carbonization furnace.

  The vacuum drying apparatus 2 includes a snake pump 4 as a raw material charging means, a cake preheater 5 as a preheating means, and a string cake forming as a string raw material forming means from the upstream side to the downstream side in the conveying direction of the sludge cake. A vessel 6, a first stage drying container 7, a second stage drying container 8, and a gate valve 9 as a raw material derivation means are arranged in this order. Hereinafter, each device will be described.

  The snake pump 4 includes a stator having a female screw formed of an elastic material inside a metal outer cylinder, and a male screw-shaped metal rotor inserted into the stator. The sludge cake is pumped toward the cake preheater 5 while the rotor is eccentrically revolving with respect to the stator. Since this snake pump is conventionally well-known, detailed description here is abbreviate | omitted. Since the conveying pressure by the snake pump 4 is generally higher than the conveying pressure of the screw conveyor, the sludge cake is forcibly fed toward the cake preheater 5 by a relatively high conveying pressure. Become. As a result, by continuously feeding the sludge cake to the first stage drying container 7, the sludge cake itself seals the upstream end opening of the first stage drying container 7 (sludge is upstream of the first stage drying container 7). As long as the sludge cake is continuously charged, the internal space of the first-stage drying container 7 is not opened to the atmosphere.

  The cake preheater 5 includes a sludge conveyance path 51 inside, and a warm air jacket 52 through which the warm air circulates on the outer periphery of the sludge conveyance path 51. A hot air introduction pipe 53 and a hot air discharge pipe 54 are connected to the hot air jacket 52. Thereby, the warm air (about 100 to 200 ° C.) introduced from the warm air introduction pipe 53 passes through the warm air jacket 52, and at this time, the thermal energy is given to the sludge in the sludge transporting path 51 to warm it. The air is exhausted from the wind exhaust pipe 54. Thereby, in the cake preheater 5, sludge is preheated and temperature rises to about 60-90 degreeC, for example. Further, steam may be used instead of warm air for cake preheating.

  Moreover, as shown in FIGS. 3A to 3C, the cross-sectional shape of the sludge conveyance path 51 in the cake preheater 5 changes from a circular shape to a flat shape gradually toward the downstream side in the conveyance direction. ing. 3A is a cross-sectional view taken along the line AA in FIG. 2 (a plan view of the periphery of the cake preheater 5), FIG. 3B is a cross-sectional view taken along the line BB in FIG. 2, and FIG. It is a CC sectional view taken on the line.

  The string-like cake molding machine 6 is configured to mold the sludge preheated in the cake preheater 5 and formed into a flat shape into a plurality of string-like shapes. Specifically, as shown in FIG. 2 (plan view), splitters 61, 61,... Are provided at a plurality of locations inside the sludge transport path, and sludge passes between the splitters 61, 61,. At this time, the sludge is formed into a plurality of strings extending along the conveying direction. In this embodiment, splitters 61, 61,... Are arranged at three locations inside the sludge conveyance path, and four string sludges are formed and introduced into the first stage drying container 7. Yes. As the shape of this splitter 61, as shown in FIG.4 and FIG.3 (d) (DD sectional view in FIG. 2), the triangular pyramid shape from which a cross-sectional area becomes large gradually toward the conveyance direction of sludge. Then, the edge 62 existing on the outer surface of the splitter 61 can prevent the sludge from clogging the fibers and the hair in the sludge and causing them to clog the sludge in the conveyance path. Yes.

  The first stage drying container 7 includes a belt conveyor 71 as a conveying means inside, and the sludge formed into a plurality of strings by the string cake forming device 6 is directed toward the second stage drying container 8. It is designed to be transported. On the other hand, the second-stage drying container 8 is disposed below the first-stage drying container 7, and includes a screw conveyor 81 as a conveying means therein, and is supplied from the first-stage drying container 7. The sludge is transported toward the gate valve 9.

  In addition, as a configuration of the connection portion between the first stage drying container 7 and the second stage drying container 8, sludge is disposed on the lower surface of the first stage drying container 7 and at a position corresponding to the downstream end in the conveying direction of the belt conveyor 71. While a discharge hole 72 is formed, a sludge introduction hole 82 is formed on the upper surface of the second stage drying container 8 at a position corresponding to the upstream end in the conveying direction of the screw conveyor 81. The sludge discharge hole 72 and the sludge introduction hole 82 are connected by a connecting pipe 73. With such a configuration, the first-stage drying container 7 and the second-stage drying container 8 constitute a decompression container referred to in the present invention. For this reason, the upstream opening of the first stage drying container 7 serves as a raw material introduction port referred to in the present invention, and the downstream opening of the second stage drying container 8 serves as a raw material discharge port referred to in the present invention.

  A suction pipe 83 is connected to the side wall of the second stage drying container 8 on the downstream side in the sludge transport direction, and a vacuum pump 84 as a decompression means is connected to the suction pipe 83. That is, as the vacuum pump 84 is driven, the air present in the first stage drying container 7 and the second stage drying container 8 is drawn out so that the internal spaces of these containers 7 and 8 are in a vacuum state. It has become. In this embodiment, for example, a degree of vacuum of about 1/10 atm is obtained. The degree of vacuum in the internal space of the containers 7 and 8 is not limited to this.

  Thus, the boiling point of the moisture contained in the sludge is lowered by transferring the sludge from the first-stage drying container 7 to the second-stage drying container 8 in a state where the internal space is in a vacuum state. However, a large amount of water is released from the sludge during the transportation. Further, a warm air jacket 85 as a heating means through which warm air circulates is provided on the outer periphery of the second stage drying container 8, and the sludge is heated while being conveyed by the warm air passing through the warm air jacket 85. As a result, a large amount of water is released from the sludge. Further, steam may be used instead of the warm air.

  Further, an air supply pipe 74 as an air injecting means for supplying air toward the internal space of the first stage drying container 7 is connected to the vicinity of the upstream end in the sludge transport direction on the upper surface of the first stage drying container 7. Has been. The air supply pipe 74 is provided with an open / close valve 75, and air is supplied to the internal space of the first stage drying container 7 when the open / close valve 75 is opened. Thus, when air is supplied to the internal space of the first-stage drying container 7, the internal space of the first-stage drying container 7 is depressurized, so that the air expands toward the vacuum pump 84. Will flow at high speed. The steam in the internal space of the first-stage drying container 7 and the second-stage drying container 8 also flows toward the vacuum pump 84 along this high-speed air flow, whereby the water vapor remaining in each of the drying containers 7 and 8 is Thus, the amount of water remaining in the drying containers 7 and 8 is greatly reduced, and the drying of sludge can be promoted. If dry air is used as the injected air, a higher effect can be obtained.

  In addition, the conveyance speed of the sludge in the belt conveyor 71 and the screw conveyor 81 is set according to the heat amount given to the sludge from the degree of vacuum in each drying container 7 and 8 and the warm air jacket 85. For example, as the sludge transport speed, the first stage drying container 7 has a sludge drying time of 30 to 45 minutes, and the second stage drying container 8 has a sludge drying time of 30 to 60 minutes. Is set.

  By such an operation, the moisture content of the sludge is significantly reduced, and for example, after reaching a moisture content of about 40%, the sludge falls from the downstream end of the second stage drying vessel 8 toward the gate valve 9. ing.

  FIG. 5 shows the state of sludge in each part of the first-stage drying container 7 and the second-stage drying container 8. FIG. 5A shows the state of sludge (string shape) on the belt conveyor 71 immediately after being discharged from the string cake forming device 6. FIG. 5B shows sludge in a state where moisture is released and the surface is substantially dried in the process of being conveyed on the belt conveyor 71 in the first-stage drying container 7. FIG. 5 (c) shows that the sludge is partially cut due to the influence of gravity when falling from the downstream end in the transport direction of the belt conveyor 71 in the first stage drying container 7 toward the connecting pipe 73. This shows the state of string sludge. That is, the string-like sludge is folded each time a predetermined dimension protrudes from the downstream end in the conveying direction of the belt conveyor 71, and the broken sludge becomes a short string-like sludge through the connecting pipe 73 and the second-stage drying container 8. Will fall. The sludge introduced into the second stage drying container 8 is conveyed while being stirred by the screw conveyor 81. FIG. 5 (d) shows sludge that is formed into a substantially spherical shape having a smooth surface, in which moisture is released in the course of being conveyed on the screw conveyor 81 in the second-stage drying container 8. In this way, in each of the dryers 7 and 8, the sludge that has been dried to a moisture content of about 40% and formed into a substantially spherical shape is dropped from the downstream end of the second stage drying vessel 8 toward the gate valve 9. Will be.

  Next, the gate valve 9 will be described. As shown in FIG. 6, the gate valve 9 includes two rotary valves (an upstream first rotary valve 91 and a downstream second rotary valve 92). These rotary valves 91 and 92 are rotationally driven independently of each other, and switch between opening and closing of the sludge conveyance path.

  Further, the upstream path I of the first rotary valve 91, the downstream path III of the second rotary valve 92, and the path II between the rotary valves 91 and 92 communicate with each other by pressure equalizing paths 93 and 94. The first on-off valve 95 is provided in the upstream pressure equalizing path 93 that connects the upstream path I of the first rotary valve 91 and the path II between the rotary valves 91 and 92, and the second rotary valve 92. The second on-off valve 96 is disposed in the downstream pressure equalizing path 94 that connects the downstream path III and the path II between the rotary valves 91 and 92. That is, when the first on-off valve 95 is opened, the pressure on the upstream path I of the first rotary valve 91 and the path II between the rotary valves 91 and 92 is equalized, while the second on-off valve 96. Is opened, the path III on the downstream side of the second rotary valve 92 and the path II between the rotary valves 91 and 92 are equalized.

  Hereinafter, the operation of the gate valve 9 will be described. First, as shown in FIG. 6 (a), when the first rotary valve 91 is closed and the second rotary valve 92 is opened, and when the on-off valves 95 and 96 are both closed, When sludge is dropped and supplied from the downstream end of the two-stage drying container 8 and the supply amount reaches a predetermined amount, first, the second rotary valve 92 is closed as shown in FIG. In this state, the first on-off valve 95 is opened, and the upstream path I of the first rotary valve 91 and the path II between the rotary valves 91 and 92 are equalized. Thereafter, as shown in FIG. 6C, the first rotary valve 91 is opened. Thereby, the sludge which existed in the path | route I of the upstream of the 1st rotary valve 91 falls in the path | route II between each rotary valve 91,92. At this time, since these spaces I and II are already in a pressure-equalized state, the sludge falls smoothly.

  Next, as shown in FIG. 6B, the first rotary valve 91 is closed. In this state, the first on-off valve 95 is closed and the second on-off valve 96 is opened, so that the path III on the downstream side of the second rotary valve 92 and the path II between the rotary valves 91 and 92 are equalized. Pressed. Thereafter, as shown in FIG. 6A, the second rotary valve 92 is opened. As a result, the sludge existing in the path II between the rotary valves 91 and 92 falls toward the hot stove 3. At this time, since these spaces II and III are already in a uniform pressure state, the sludge falls smoothly. By repeating such an operation, the sludge can be sequentially supplied to the hot stove 3 without the internal spaces of the drying containers 7 and 8 being opened to the atmosphere.

  As a feature of each of the rotary valves 91 and 92, as shown in FIG. 7 (a perspective view of a part of the rotary valves 91 and 92), a urethane rubber 9A is provided on the outer peripheral surface thereof. As a result, when the rotary valves 91 and 92 are in the closed state, the urethane rubber 9A is pressed against the inner surface of the supply passage, and the closed state of the valve can be obtained with high airtightness. Yes. That is, when the space below the rotary valves 91 and 92 is higher than the space above, the urethane rubber 9A is pressed against the inner surface of the supply path by the pressure difference, and has high airtightness. While a closed state of the valve is obtained, when a pressure equalizing operation is performed in association with opening of the on-off valves 95 and 96, there is no pressure difference between the lower space and the upper space of the rotary valves 91 and 92. Therefore, the urethane rubber 9A is not pressed against the inner surface of the supply path, and the rotary valves 91 and 92 can be easily rotated.

  Furthermore, the edge portion 9B on the outer peripheral surface of the rotary valves 91 and 92 is processed at an acute angle, and even when foreign matter is present in the supply path, it is cut by the edge portion 9B to a predetermined closed state. It can be rotated. Further, if the piping on the pressure reducing containers 7 and 8 side of the on-off valve 95 is connected as shown by the broken line in FIG. 6D (pipe 93A) and connected to the inlet air inlet side, The drying effect can be enhanced while reducing the amount of inflow of air.

  The hot stove 3 into which the sludge dried by the reduced pressure drying apparatus 2 configured as described above is installed includes a screw conveyor 31 for sludge conveyance and a gas burner 32 attached to the lower portion thereof. The inside of the hot stove 3 can be heated to about 500 to 700 ° C. by 32 flames. Note that LPG is used as the fuel for the gas burner 32, but the fuel for the burner may be LNG, kerosene, or heavy oil, and is not limited thereto.

  As described above, according to the carbonization treatment apparatus 1 according to the present embodiment, the drying treatment is performed while the sludge is being conveyed. Therefore, the highly efficient drying operation is achieved while reducing the size of the apparatus as compared with the conventional batch-type drying apparatus. Can be realized. The amount of raw materials that can be processed per unit time can be greatly increased.

-Other examples-
In the embodiment described above, the case where the present invention is applied to the carbonization apparatus for carbonizing the sludge cake obtained by dewatering the concentrated sludge in the water treatment system has been described. The present invention is not limited to this, and can be applied to various raw materials such as coffee beans, tea leaf straw, beef barn stables, chicken manure, rice husks, vegetable waste straw, cut grass, and the like. In particular, it is suitable for drying treatment of foods containing a large amount of starch. Moreover, the reduced pressure drying apparatus according to the present invention is not limited to use as a pretreatment for the carbonization treatment operation but can be applied to other uses. That is, you may use as a drying apparatus single-piece | unit.

  In the above embodiment, the case where the volume of the raw material having a water content of 70% is reduced to about 1/10 to 1/20 has been described. However, according to the present invention, the raw material having a water content of about 90% Can be sufficiently carbonized, and the volume of the raw material can be reduced to about 1/30.

  Further, although the hot air jacket 85 is employed as a means for heating the sludge conveyed in the second stage drying container 8, heating with a burner may be performed instead.

  Furthermore, each of the string-like sludges formed by the string-like cake forming machine 6 has an individual (not connected) string shape. However, as shown in a cross section in FIG. The shape may be connected in a direction orthogonal to each other. Also in this case, after the sludge is dried, the respective connecting portions D, D,... Are cut off, and as in the case of the above-described embodiment, a short string-like sludge is formed, which contributes to the generation of granular charcoal.

  Further, a stirrer may be provided in the drying containers 7 and 8 in place of the belt conveyor 71 and the screw conveyor 81 so that the hydrated raw material continuously fed is gradually dried while being stirred in the drying container. Good. Moreover, in the carbonization process part in a hot stove, it can replace with the screw conveyor 81 for a heating conveyance means, and can also use a rotary kiln system.

  The vacuum drying apparatus according to the present invention can be used when used as an apparatus for drying a sludge cake under reduced pressure as a pre-process when carbonizing sludge cake generated in a water treatment system to obtain a soil improvement material. is there.

It is a figure which shows schematic structure of the carbonization processing apparatus which concerns on embodiment. It is a top view which shows a 1st stage drying container and its peripheral part. 2A is a sectional view taken along line AA in FIG. 2, FIG. 2B is a sectional view taken along line BB in FIG. 2, FIG. 2C is a sectional view taken along line CC in FIG. FIG. It is a perspective view of a splitter. It is a perspective view which shows the state of the sludge in each part of a 1st stage drying container and a 2nd stage drying container. It is sectional drawing for demonstrating operation | movement of a gate valve. It is a perspective view which shows a part of rotary valve. It is a figure which shows the modification of the cross-sectional shape of the sludge shape | molded with a string-like cake shaper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Carbonization processing apparatus 2 Vacuum drying apparatus 3 Hot stove 4 Snake pump (raw material input means)
5 Cake preheater (preheating means)
6 String cake former 7 First stage drying container (depressurized container)
71 Belt conveyor (conveying means)
8 Second stage drying container (depressurized container)
81 Screw conveyor (conveying means)
84 Vacuum pump (pressure reduction means)
9 Gate valve (raw material derivation means)

Claims (9)

In a vacuum drying apparatus that performs a drying process of a hydrous raw material,
A decompression vessel having a raw material inlet and a raw material outlet;
Decompression means for bringing the internal space of the decompression container into a decompressed state;
When charging the raw material into the vacuum container from the raw material inlet, by continuously charging the raw material, raw material charging means for charging the raw material while sealing the raw material inlet by this raw material,
A vacuum drying apparatus, comprising: a raw material derivation unit for deriving the raw material from the raw material discharge port of the vacuum container while preventing the internal space of the vacuum container from being released to the atmosphere from the raw material discharge port. In a vacuum drying apparatus that performs a drying process of a hydrous raw material,
A decompression vessel having a raw material inlet and a raw material outlet;
Decompression means for bringing the internal space of the decompression container into a decompressed state;
When charging the raw material into the vacuum container from the raw material inlet, by continuously charging the raw material, raw material charging means for charging the raw material while sealing the raw material inlet by this raw material,
Conveying means for gradually drying the water-containing raw material while conveying the raw material from the raw material inlet to the raw material outlet in the internal space of the decompression vessel;
A vacuum drying apparatus, comprising: a raw material derivation unit for deriving the raw material from the raw material discharge port of the vacuum container while preventing the internal space of the vacuum container from being released to the atmosphere from the raw material discharge port. The reduced-pressure drying apparatus according to claim 1 or 2,
A reduced-pressure drying apparatus comprising heating means for heating the raw material in the inner space of the reduced-pressure container. The reduced-pressure drying apparatus according to claim 1, 2, or 3,
A vacuum drying apparatus comprising preheating means for heating a water-containing raw material prior to charging the raw material into the vacuum container from the raw material inlet. In the vacuum drying apparatus as described in any one of Claims 1-4,
A reduced-pressure drying apparatus comprising a string-shaped raw material forming means for forming a raw material charged into a vacuum container from a raw material inlet into a string shape extending along the charging direction. In the vacuum drying apparatus according to any one of claims 1 to 5,
An air injection means for injecting air into the internal space of the decompression vessel;
The vacuum drying apparatus, wherein the air injection means is provided in the vicinity of the raw material introduction port in the decompression container, while the decompression means is provided in the vicinity of the raw material discharge port in the decompression container. A carbonization apparatus for carbonizing a water-containing raw material by heating,
The reduced-pressure drying apparatus according to any one of claims 1 to 6,
A carbonization processing apparatus comprising: a carbonization furnace in which a raw material dried by the reduced pressure drying apparatus is charged and the raw material is carbonized by heating. In the vacuum drying method performed by the vacuum drying apparatus according to any one of claims 1 to 6,
The raw material is continuously introduced into the vacuum vessel while the raw material inlet of the vacuum vessel whose internal space is previously maintained in a reduced pressure state is sealed with the raw material, and the water-containing raw material that has been continuously added is placed in the vacuum vessel. A reduced-pressure drying method characterized by being dried gradually while being conveyed by a conveying means. In the vacuum drying method performed by the vacuum drying apparatus according to any one of claims 1 to 6,
The raw material is continuously introduced into the vacuum vessel while the raw material inlet of the vacuum vessel whose internal space is previously maintained in a reduced pressure state is sealed with the raw material, and the water-containing raw material that has been continuously added is placed in the vacuum vessel. A method of drying under reduced pressure, wherein the method is gradually dried while stirring.

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