JP2007000820A - Pipe transportation method and apparatus of dehydrated cake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe transportation method of a dehydrated cake which improves suction efficiency of a pressure pump without using a special pushing device, and has a small increase in pressure loss resistance of a transport pipe on the discharge side of the pressure pump. <P>SOLUTION: Before the dehydrated cakes are fed to the pressure pump (20), a shearing force is applied to the cakes by a chopper (10) to fluidize or liquefy the dehydrated cakes, which are a plastic body. The fluidized or liquefied dehydrated cakes are directly fed to the pressure pump (20) through a screw feeder (30). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention supplies a dewatered cake obtained by dewatering from sewage sludge, sewage sludge, etc. generated in a sewage treatment plant, etc., to the pump, and drives the pump to transport the pipe to a predetermined location. More particularly, the present invention relates to a pipe transporting method and a transporting device for dehydrated cake characterized by the treatment of the dewatered cake before being supplied to a pump.

  Sewage sludge, sewage sludge, and the like generated at the sewage treatment plant are dehydrated by a filter press so as to have a moisture content of 60 to 80%, and are transported to an incinerator, for example, and incinerated. Such dewatered cake can be transported to an incinerator by an endless conveyor such as a belt conveyor, but pipe transportation is more suitable. Since it is transported in a closed space called a pipe, it has the advantage of less polluting the environment, the area occupied by the pipeline is small compared to the transport volume, and the transportation route can be changed freely by simply changing the piping. This is because it also has advantages such as.

  In order to transport such a dehydrated cake by a pipe, a pressure feed pump for pressing the dehydrated cake into the transport pipe, for example, a reciprocating volumetric pump is required. A typical example of a reciprocating positive displacement pump is a piston pump, which sucks a conveyed product into a cylinder during a piston suction stroke and press-fits it into a transport pipe during a discharge stroke. This piston pump is widely used because it has a high discharge pressure and can be transported over a long distance.

  However, there are various problems. For example, when transporting highly viscous substances such as dehydrated cakes by pipe, the pressure loss resistance in the transport pipe determines the discharge pressure of the pump, but generally the pressure loss resistance increases as the moisture content decreases. The pump's rated discharge pressure will be exceeded. Therefore, there is a problem that measures such as reducing the transportation amount must be taken. Moreover, the flow state of the dewatered cake deteriorates the state of inflow into the pump, and the suction efficiency of the dewatered cake is deteriorated, which may adversely affect the discharge amount performance of the dewatered cake itself. Furthermore, dehydrated cakes such as sewage sludge often have different physical properties such as pressure loss resistance and fluidity in the transport pipe even if the moisture content is the same due to differences in location, dehydration process, etc. There is also the problem of having to deal with this.

JP 7-291445 A Japanese Patent No. 3620871 Japanese Patent Publication No. 6-12160

  Thus, various methods for transporting dehydrated cake pipes have been proposed. For example, in Patent Document 1, when sludge is pushed into a reciprocating volumetric pump by a screw feeder, and the pump is driven and pumped, the pushing pressure by the screw feeder is controlled by the sludge transportation speed, moisture content, density, etc. However, a transportation method is shown in which the charging efficiency of the reciprocating positive displacement pump is constant. Further, in Patent Document 2, when a dehydrated cake is transported by injecting a lubricant such as water from a water injection device between the outer peripheral portion of the dehydrated cake and the inner peripheral wall of the transport pipe, the target absolute pressure in the transport pipe of the conveyed product Compare the measured absolute pressure with the measured absolute pressure, and if they are almost the same, the injection amount of the lubricant is also generally appropriate. In this case, even if the target pressure loss and the measured pressure loss are different, the injection amount is slightly changed. However, if the target absolute pressure is different from the measured absolute pressure, the current injection amount is not appropriate at this time, so the injection amount is changed relatively large. If the target pressure loss and the measured pressure loss are different at this time, a pumping method is disclosed in which the injection amount is changed relatively large. Furthermore, Patent Document 3 discloses a method of injecting a lubricant such as water in the middle of a transport pipe when a highly viscous substance is transported by a pump by two pumps. A pipe transportation method in which a lubricant is injected so that the pressure difference between the two is within a set value range is shown.

As described above, according to the invention described in Patent Document 1, the indentation pressure to the pressure pump is controlled by the sludge transport speed, moisture content, density, etc. The advantage of being able to push into is recognized. Moreover, according to the invention described in each of Patent Documents 2 and 3, the dehydrated cake is transported while injecting a lubricant such as water from the water injection device between the outer peripheral portion of the dehydrated cake and the inner peripheral wall of the transport pipe. As a result, the moisture content of sludge does not increase, the increase in pressure loss resistance in the transport pipe can be suppressed, and long-distance transport is possible without any clogging problems. Is recognized. In particular, according to the inventions described in Patent Documents 2 and 3, since the injection amount of water, lubricant, etc. is controlled by the detected pressure value in the transport pipe, there is an advantage that the injection amount can be controlled to the necessary minimum amount. Yes, there is no particular problem on the downstream side from the pressure pump, and it is implemented effectively.
However, there is room for improvement upstream of the pump, that is, on the suction side. To explain further, since a controlled amount of lubricant is injected in the middle of the transport pipe, transportation corresponding to various dehydrated cakes having different physical properties such as moisture content and specific gravity can be performed. The above-described lubricant injection operation in the transport pipe on the downstream side of the pressure pump has no effect on the suction side of the pressure pump. Therefore, there is nothing other than setting a low suction efficiency, and sufficient transport efficiency cannot be improved.

  However, since the invention described in Patent Document 1 is provided with a screw feeder, sludge can be pushed into the pumping pump without excess or deficiency with this feeder, but this screw feeder is a transport pipe downstream of the pumping pump. It is controlled by the transport speed, moisture content, etc. measured in the above, and does not improve the properties of the dehydrated cake supplied to the pressure pump. Moreover, according to the invention described in Patent Document 2, the pressure feed pump is supplied by a screw feeder, but this screw feeder only has an effect of pushing in the dewatered cake. Furthermore, in the accompanying drawing of Patent Document 3, a hopper is provided to supply the dehydrated cake to the pressure pump, and a stirring blade is shown in the hopper. It is presumed to be used and does not improve the physical properties of the dehydrated cake.

  More specifically, since the screw feeder is a rotary type, it is continuously supplied. However, since the pressure feed pump filled by the screw feeder is a reciprocating type, it is intermittently filled. In order to transport sludge in this way, continuous supply and intermittent filling must be matched, so the screw feeder alone changes the amount or speed of sludge transport, moisture content of sludge, specific gravity, etc. It is not possible to sufficiently cope with changes in the physical properties. For example, when the transport amount or transport speed increases and the piston pulling speed of the piston pump increases, the sludge cannot follow the piston pulling speed with a small pressing pressure. If it does so, the filling efficiency to the cylinder of a piston pump will become small. In an extreme case, a gap that is not filled in the cylinder may occur. When the packing density is low, the initial stage of the piston stroke is simply compressed without the sludge being transported, not only the transport efficiency is reduced, but also the discharge pressure is pulsated, and the pump is pumped. Also cause vibration of transportation pipes.

  When the filling efficiency is low in this way, the pipe transportation is hindered, but this problem can be solved to some extent by increasing the pushing pressure of the screw feeder. However, if it is made higher than necessary, the power cost of the screw feeder is increased and the structure must be made strong, resulting in a cost problem. Furthermore, when the pushing pressure is high, the piston pump may be blocked at the suction port.

  An object of the present invention is to provide a dehydrated cake pipe transport method and transport device that eliminates the above-mentioned conventional problems or drawbacks, and specifically, without using a special pushing device, a pressure pump An object of the present invention is to provide a pipe transporting method and a transporting device for a dehydrated cake, in which the suction efficiency of the water is improved and the increase in pressure loss resistance in the transport pipe on the discharge side of the pump is small.

Sludge generated from a sludge treatment plant or the like is generally dehydrated to a moisture content of 60 to 80% to form a dehydrated cake. A dehydrated cake having such a moisture content is soft, but is a plastic that can retain its shape. Therefore, in order to achieve the above object, the present invention applies a shearing force to the dewatered cake before supplying it to the pump. Then, the dehydrated cake that is a plastic body is fluidized or liquefied. The dewatered cake that has been fluidized or liquefied is supplied to the pressure pump directly or via a mechanical rotary feeder such as a screw feeder. Thus, the invention described in claim 1 supplies a dewatered cake obtained by dewatering from sewage sludge, sewage sludge, etc. generated in a sewage treatment plant etc. to a pump, and drives the pump to When the pipe is transported to a location, the dehydrated cake is supplied by being fluidized or liquefied by a shear blade before being supplied to the pressure pump.
The invention according to claim 2 supplies a dewatered cake obtained by dewatering from sewage sludge, sewage sludge, etc. generated in a sewage treatment plant etc. to a pump, and drives the pump to a predetermined location. When transporting the pipe, the dewatered cake is coarsely pulverized by a stirring blade and supplied by fluidization or liquefaction using a shear blade before being supplied to the pressure pump. According to a third aspect of the present invention, in the transport method according to the first or second aspect of the present invention, the dehydrated cake that has been fluidized or liquefied is supplied to a pressure pump by a rotary supply device.
The invention according to claim 4 is connected to the pressure pump, the supply device for supplying the dewatered cake to the pressure pump, and the downstream side of the pressure pump. A dewatering cake is supplied to the pumping pump via the supply device, and when the pumping pump is driven, the dewatering cake is pumped to a predetermined location via the transporting pipe. In the pipe transport device, the supply device is provided with a shear blade for fluidizing or liquefying the dewatered cake. According to a fifth aspect of the present invention, in the pipe transport device according to the fourth aspect, the supply device comprises a cake storage hopper, and a stirring blade and a shear blade are provided in the cake storage hopper. According to a sixth aspect of the present invention, in the pipe transport device according to the fourth aspect, the supply device is a mechanical rotary feeder, and a shear blade is provided on at least one of the supply side and the discharge side of the feeder. It has been. According to a seventh aspect of the present invention, in the pipe transportation device according to the fourth aspect, the supply device comprises a dehydrated cake introduction member connected to the suction port of the pressure pump, and a shear blade is provided inside the introduction member. It has been.

  As described above, according to the present invention, when the dewatering cake is supplied to the pumping pump, and the pumping pump is driven to transport the pipe to a predetermined place, before the dewatering cake is supplied to the pumping pump, the shearing blade is used. Since it is supplied after being fluidized or liquefied, the dewatering cake can sufficiently follow the pulling speed of the piston even if the pressure pump is reciprocating and intermittent suction is performed. The suction efficiency is improved. Therefore, the performance of the pressure pump is also improved. In addition, since the dehydrated cake is supplied after being fluidized or liquefied, the pressure loss resistance in the transport pipe is also reduced, and special water and lubricants are used to reduce the discharge pressure of the pressure pump. The injection of a new lubricant is also unnecessary. That is, injection of a lubricant such as water is a contradictory operation of adding water again to the dehydrated cake, although it is possible to transport the pipe, and this operation becomes unnecessary. Therefore, the effect which contributes to energy reduction, such as a combustion process which is a post process after pumping, is also acquired. Due to these effects, the pipe transportation apparatus is inexpensive, and the overall efficiency of the pumping pump is improved, and the pumping power cost, that is, the running cost is reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. First, as shown in FIG. 1A, an example in which the cake storage hopper 1 is applied as a supply device and the reciprocating volume pump 20 is applied as a pressure pump will be described. The pipe transport apparatus according to the present embodiment includes a cake storage hopper 1, a reciprocating volume pump 20, a transport pipe 25, and the like. The dehydrated cake is obtained as described with respect to the prior art and is temporarily stored in the cake storage hopper 1 and fluidized or liquefied. The dehydrated cake supplied to the reciprocating volume pump 20 and fluidized or liquefied by driving the reciprocating volume pump 20 is stored in a destination, for example, an incinerator or an incinerator. It is transported to the bottle.

  The cake storage hopper 1 includes a hopper 2 having a conventionally known form. At the top of the hopper 2, a dehydrated cake charging port 3 is provided, and the lower open end 4 is connected to the suction port of the reciprocating volumetric pump 10. Inside the hopper 2 configured in this manner, scrapers 5 and 5 are provided as pulverizing blades for roughly pulverizing the supplied dewatered cake. A chopper 10 composed of a plurality of blades is provided as a shear blade for fluidizing or liquefying. The arms 6 and 6 of the scrapers 6 and 6 are attached to a rotating body 7 rotatably provided on the upper portion of the hopper 2, and the rotating body 7 is connected to an electric motor or power via a power transmission means 8 such as a belt. The hydraulic motor 9 is driven to rotate at a relatively low speed.

  The shear blade or chopper 10 is schematically shown in FIG. 1, but one blade thereof has, for example, a propeller shape or a flat blade shape. And these blade | wings are provided in the cross shape or the spiral form so that it may balance with respect to rotation over the rotating shaft 11 over several steps at predetermined intervals. The chopper 10 configured in this way is located below the hopper 2 in the illustrated embodiment. The rotary shaft 11 extends upward, is connected to the output shaft of the transmission 12, and is driven to rotate at a relatively high speed by an electric motor or a hydraulic motor 13.

  A reciprocating positive displacement pump for pumping a highly viscous dewatering cake such as sludge is well known in the art, not to mention the literature name, and is generally composed of a cylinder and a piston. Is sucked into the cylinder and is pumped from the discharge port by forward movement. Such a reciprocating pump of the reciprocating volume pump has been proposed by the present applicant in Japanese Patent Application No. 58-60662, and will not be described in detail. Direction switching for appropriately switching between a pair of pumping piston / cylinder units for pumping the piston, a driving piston / cylinder unit for alternately driving the units, and a hydraulic circuit provided corresponding to these units It is roughly composed of a valve. As described above, the reciprocating double-row type positive displacement pump is well known in the art and is also disclosed in the above-mentioned patent application of the present applicant. Therefore, in FIG. A dynamic volume pump 20 and a driving piston / cylinder unit 21 are shown.

  Next, the operation of the above embodiment will be described. A dehydrated cake is supplied to the hopper 2. The scrapers 5 and 5 are driven to rotate at a relatively low speed by the motor 4. The chopper 10 is driven to rotate at high speed by the motor 13. Then, the dehydrated cake supplied in a lump shape is coarsely pulverized by the scrapers 5 and 5 and is sheared by the chopper 10 to be fluidized. Or it becomes liquid. The hydraulic oil is supplied to and discharged from the driving piston / cylinder unit 21. Then, the dewatered cake fluidized as described above is sucked into the reciprocating volume pump 20 for pressure feeding and discharged into the transport pipe 25. As a result, the dehydrated cake is sequentially pumped through the transport pipe 25 to a predetermined location.

  According to the present embodiment, since the dewatered cake is fluidized or liquefied before being supplied to the reciprocating volumetric pump 20, the piston of the reciprocating volumetric pump 20 can be removed without any special pushing device. Even if the pulling speed is high, the cylinder is efficiently sucked into the pump, and the filling efficiency of the pump into the cylinder does not decrease. Further, since it is fluidized or liquefied, the pressure loss resistance in the transport pipe 25 is small, and the injection of lubricant as described in the section of the prior art is not particularly required.

  A second embodiment of the supply device is shown in FIG. According to the present embodiment, the hopper 2 'and the two choppers 10' and 10 'are configured. These choppers 10 ′ and 10 ′ are all attached to the lower side wall of the hopper 2 ′, and are directly rotated by a motor 13 ′. Although the scraper is not shown in FIG. 1B, a scraper or a stirring blade can be provided as a grinding blade. It is clear that this embodiment also operates in substantially the same manner as the above-described embodiment.

  A third embodiment of the supply device is shown in FIG. According to the present embodiment, the screw feeder 30 is arranged in the horizontal direction, the upstream side is connected to a hopper (not shown), the downstream side is bent downward, and the tip is a reciprocating positive displacement pump as described above. It is designed to be connected to the inlet. Choppers 10 ′ and 10 ′ are provided on the supply side and the discharge side of the screw feeder 30 configured as described above. Although a motor for driving the screw 31 of the screw feeder 30 is not shown, the rotation speed of this motor is controlled by an inverter circuit, for example, so that the pushing pressure of the dewatering cake to the reciprocating volumetric pump can be kept at a predetermined value. It has become. It is obvious that the same operation as in the first and second embodiments is performed as a whole.

  The present invention is not limited to the above-described embodiment, and can be implemented in various forms. For example, the rotation speed of the motors 4, 13, 13 'can be changed according to the properties of the dewatered cake. Further, it is obvious that the number and arrangement positions of the scrapers and choppers are not limited to the illustrated embodiment. Further, it is obvious that the rotary feeder can be used instead of the screw feeder 30. Further, in FIG. 1B, two choppers 10 'and 10' are shown. However, one chopper can be implemented, or it can be combined with other stirring blades. In the embodiment shown in FIG. 1C, the chopper 10 ′ is provided on each of the supply side and the discharge side of the screw feeder 30, but the same effect can be obtained if provided on at least one of them. It is clear that is obtained. Furthermore, although not shown in FIG. 1, a dewatering cake introduction member can be provided at the suction port of the pressure pump, and a chopper 10 'can be provided inside the introduction member.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment of this invention typically, (b) is the whole, (b) is 2nd Embodiment of a supply apparatus, (c) is the 3rd of supply apparatus. It is sectional drawing which shows each embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cake storage hopper 1 2, 2 'hopper 5 Scraper 10, 10' Chopper 20 Reciprocating volumetric pump 25 Transport pipe
30 screw feeder

Claims (7)

When supplying dewatered cake obtained by dewatering from sewage sludge, sewage sludge, etc. generated in a sewage treatment plant to a pump, and driving the pump to transport the pipe to a predetermined location,
A method for transporting a dehydrated cake by pipe, wherein the dehydrated cake is supplied after being fluidized or liquefied by a shear blade before being supplied to the pump. When supplying dewatered cake obtained by dewatering from sewage sludge, sewage sludge, etc. generated in a sewage treatment plant to a pump, and driving the pump to transport the pipe to a predetermined location,
A method for transporting a dehydrated cake by pipes, characterized in that the dehydrated cake is coarsely pulverized by a stirring blade and fluidized or liquefied by a shear blade before being supplied to the pump.   3. The transport method according to claim 1 or 2, wherein the dehydrated cake that has been fluidized or liquefied is supplied to the pump by a rotary supply device. A pressure pump, a supply device provided on the upstream side of the pressure pump, and a dehydrating cake for supplying the dehydrated cake to the pressure pump; and a transport pipe connected to the downstream side of the pressure pump,
A dewatering cake is supplied to the pumping pump via the supply device, and when the pumping pump is driven, the dewatering cake is pumped to a predetermined location via the transporting pipe. And
The dehydrating cake pipe transporting apparatus, wherein the feeding device is provided with shear blades for fluidizing or liquefying the dewatering cake.   5. The pipe transport device according to claim 4, wherein the supply device is a cake storage hopper, and the stirring blade and the shear blade are provided in the cake storage hopper.   5. The pipe transport apparatus according to claim 4, wherein the supply device is a screw feeder, and at least one of the supply side and the discharge side of the screw feeder is provided with a shear blade. apparatus.   5. The pipe transport apparatus for dehydrated cake according to claim 4, wherein the supply device comprises a dehydrated cake introduction member connected to a suction port of a pumping pump, and a shear blade is provided inside the introduction member.

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