JPH067799A - Transport and drying method by dehydrated cake pipeline - Google Patents

Abstract

PURPOSE:To prevent the rising of viscosity in a pipeline and to achieve the reduction of water content, in the transport and drying of org. sludge, by heating a dehydrated cake under stirring during transport by the hot water jacket provided to the outer periphery of a transport pipeline and charging the heated cake in a hopper under negative pressure to hold the same to a reduced pressure state. CONSTITUTION:A dehydrated cake is sent into a transport pipeline 2 by a uniaxial screw type pressure feed pump 1. A hot water jacket 3 is arranged to the outer periphery of the transport pipeline 2 and the dehydrated cake during transport is heated to be lowered in its viscosity. The dehydrated cake is stirred through a static mixer 5 to be uniformized in its viscosity and the heat conduction efficiency of the dehydrated cake is enhanced. The dehydrated cake thus fed is charged in a hopper 6 reduced in pressure by a suction fan 8 to be brought to a pressure reduced state and dried by the evaporation of moisture. The hopper 6 is connected to a deodorizing tower 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transporting a dehydrated cake of organic sludge by a pipe and a method for drying the dehydrated cake.

[0002]

2. Description of the Related Art Conventionally, organic sludge discharged from a sewage treatment plant or the like has been dehydrated to reduce its water content to some extent and then incinerated in an incineration plant or the like. When transporting the dehydrated cake, the water content is 75 to 85.
% Of the dehydrated cake was pushed into the pipeline by a uniaxial screw pump and pressure-fed to the cake hopper in the subsequent step through the pipeline.

[0003]

However, the dehydrated cake has a much higher viscosity than water, and the pump discharge pressure is as high as 5 to 10 kg / cm ² even if the pipe diameter is made three times larger than the pump bore diameter or more. Therefore, there is a problem that the required power of the uniaxial screw type pump reaches several tens of kW and the running cost becomes high. Also,
There is a problem that the total length of the uniaxial screw type pump becomes long and the drive motor also becomes large. Furthermore, since the flow velocity in the pipeline is as slow as 0.1 to 0.5 m / sec, the residence time of the dehydrated cake in the pipeline becomes long, and the viscosity of the dehydrated cake increases due to cooling by heat dissipation, resulting in a large pressure loss. was there.

On the other hand, if the water content is increased in order to suppress the viscosity of the dehydrated cake, there is a problem that the fuel used in the incineration process increases. The present invention is to solve the above problems, and to suppress the increase in the viscosity of the dehydrated cake in the middle of the pipeline, and to provide a method for transporting and drying the dehydrated cake by the pipeline that can reduce its water content. To aim.

[0005]

In order to solve the above-mentioned problems, according to the present invention, when the dehydrated cake is pressure-fed through the transportation pipeline to the hopper, hot water is passed through a jacket provided on the outer periphery of the transportation pipeline and transported. The dehydration cake in the pipeline is heated, the dehydration cake is stirred by a static mixer inserted in the middle of the transportation pipeline, and the dehydration cake is put into the negative pressure hopper from the transportation pipeline to reduce the pressure. Is.

Further, the dehydrated cake fed into the hopper is again pressure-fed to the rear-stage hopper through the rear-stage transportation pipeline, and the dehydrated cake is repeatedly pressure-fed and depressurized. Further, the inside of the hopper is decompressed by the suction fan through the intake pipe line, and the water vaporized from the dehydrated cake is collected by the mist separator provided in the middle of the intake pipe line.

[0007]

With the above structure, the hot water passing through the jacket provided on the outer periphery of the transportation pipeline heats the dehydrated cake flowing in the transportation pipeline, and its viscosity is lowered by the temperature rise. Also,
Stirring by the static mixer homogenizes the viscosity of the dehydrated cake in the transportation pipeline and updates the heat transfer surface of the dehydrated cake in contact with the transportation pipeline, which improves heat transfer efficiency and reduces heat loss.

Therefore, since the viscosity of the dehydrated cake is reduced, the pressure loss in the transportation pipeline is reduced, the discharge pressure of the pressure pump can be reduced, and the diameter of the transportation pipeline can be reduced. Cost and running cost can be reduced.

Further, the water content of the dehydrated cake can be reduced during the pressure feeding of the transportation pipeline by heating with hot water,
It is possible to reduce the volume of the dehydrated cake and reduce the amount of disposal in the subsequent process, thereby suppressing the consumption of fuel for incineration.

Then, the dehydrated cake charged into the hopper from the transportation pipeline is changed from the consolidated state in the transportation pipeline to the depressurized state, and the water content thereof is evaporated and dried. Further, the dehydrated cake put into the hopper is again pressure-fed to the hopper in the subsequent stage through the transportation pipeline in the subsequent stage, and by repeatedly feeding and depressurizing the dehydrated cake, even a dehydrated cake with a high water content can be dried to a desired moisture content. it can.

Further, the water evaporated from the dehydrated cake is collected by the mist separator and discharged out of the system.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the cake pressure feed pump 1 is a uniaxial screw pump, and a transport pipeline 2 is connected to the discharge side of the cake pressure feed pump 1. The transport pipe 2 is provided with a jacket 3 having a double tubular shape on the outer circumference.
A heater 4 communicating with the hot water pipe 4a and the cold water pipe 4b is connected to. As the heat source of the heater 4, the heat of combustion of the digestion gas generated in the sewage treatment plant, the exhaust heat of the boiler for heating the digestion tank, and the heat of extracting the sensible heat of the sewage with a heat pump are used. A static mixer 5 is inserted in the middle of the transportation pipeline 2, and the tip end side of the transportation pipeline 2 communicates with a hopper 6.

A suction fan 8 communicates with the hopper 6 through an intake pipe line 7, and a mist separator 9 is provided in the middle of the intake pipe line 7. A deodorizing tower 10 is connected to the discharge side of the suction fan 8.

The operation of the above configuration will be described below. A dehydrated cake of organic sludge having a low water content (80% or less) is passed through a transportation pipeline 2 by a cake pressure pump 1 to a hopper 6
Pump to. At this time, the warm water heated by the heater 4 flows into the jacket 3 through the warm water conduit 4a, and the warm water passing through the jacket 3 heats the dehydrated cake through the pipe wall of the transport conduit 2. The warm water of the jacket 3 gives heat to the dehydrated cake to become cold water, and returns to the heater 4 through the cold water pipeline 4b,
After being heated again by the heater 4, the jacket 3 is cycled.
The temperature of the dehydrated cake in the transportation pipeline 2 is raised by heating with warm water, and its viscosity is reduced. In the middle of the transportation pipeline 2, the static mixer 5 stirs the dehydrated cake,
Since the viscosity of the dehydrated cake is homogenized and the heat transfer surface of the dehydrated cake that contacts the inner wall surface of the transportation pipeline 1 is renewed, the heat transfer efficiency is improved and the heat loss is reduced.

Therefore, since the viscosity of the dehydrated cake is reduced, the pressure loss in the transportation pipeline 2 is reduced, the discharge pressure of the cake pressure pump 1 can be reduced, and the diameter of the transportation pipeline 2 is also reduced. It is possible to reduce equipment cost and running cost. Furthermore, the water content of the dehydrated cake can be reduced during heating the transportation pipeline 2 by heating with warm water, and the volume of the dehydrated cake can be reduced to reduce the amount of disposal in the subsequent process and suppress the consumption of fuel for incineration. can do.

Then, the dehydrated cake is introduced into the hopper 6 which is decompressed through the intake pipe 7 by the suction fan 8 from the transport pipe 2. At this time, the moisture content of the dehydrated cake that has been reduced from the consolidated state in the transportation pipeline 2 to the reduced state is dried by evaporation. The dried dehydrated cake is carried out from the hopper 6 to a treatment facility such as an incinerator.

Further, the odor and water generated from the dehydrated cake inside the hopper 6 are sucked by the suction fan 8, and the water evaporated from the dehydrated cake is collected by the mist separator 9 and discharged to the outside of the system. At 10, the odor is removed.

FIG. 2 shows another embodiment of the present invention. Members having the same functions as those of the previous embodiment are designated by the same reference numerals and the description thereof will be omitted. In FIG. 2, a second cake pressure feed pump 11 is provided in communication with the discharge port of the hopper 6, and a second transportation pipeline 12 is provided in communication with the second cake pressure feed pump 11. Further, a second jacket 13 is provided on the outer circumference of the second transportation pipeline 12, and the second jacket 13 communicates with the heater 4 via the second hot water pipeline 4c and the second cold water pipeline 4d. . Furthermore, the second transportation line 12
A second static mixer 15 is provided in the middle of the above, and a second hopper 16 is provided at the tip end side of the second transportation pipeline 12. Further, the hopper 6 and the second hopper 16
Communicates with the suction fan 8 via a mist separator 9.

This structure corresponds to a dehydrated cake having a relatively high water content, and the dehydrated cake dried by the heating in the upstream transport pipe 2 and the depressurization in the hopper 6 is transferred by the second cake pressure pump 11. From the hopper 6 to the second hopper 1 again through the second transport line 12 in the subsequent stage.
It is possible to dry even a dehydrated cake having a high water content up to a desired water content by sending the dehydrated cake to 6 and pressing and depressurizing the dehydrated cake repeatedly. Other functions and effects are similar to those of the previous embodiment.

[0020]

As described above, according to the present invention, the dehydration cake for pressure-feeding the transportation pipeline is heated while being stirred to reduce the viscosity, thereby reducing the pressure loss in the transportation pipeline and reducing the pressure of the pump. The discharge pressure can be reduced and the pipe diameter of the transportation pipeline can be reduced to reduce equipment costs and running costs. It is possible to reduce the volume of the dehydrated cake by reducing the water content of the dehydrated cake by heating, and to evaporate the moisture content of the dehydrated cake and dry it by reducing the pressure in the hopper, thereby suppressing the consumption of the fuel for incineration.
Further, by repeating the pressure feeding and the pressure reduction of the dehydrated cake, even a dehydrated cake having a high water content can be dried to a desired water content.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a process of transporting and drying a dehydrated cake according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram showing a transportation and drying process of a dehydrated cake according to another embodiment of the present invention.

[Explanation of symbols]

 1 Cake pressure pump 2 Transport line 3 Jacket 4 Heater 5 Static mixer 6 Hopper 8 Suction fan 9 Mist separator

Claims (3)

[Claims] 1. When the dehydrated cake is pressure-fed to the hopper through the transportation pipeline, hot water is passed through a jacket provided on the outer periphery of the transportation pipeline to heat the dehydrated cake in the transportation pipeline, and A method for transporting and drying a dehydrated cake through a pipeline, which comprises stirring the dehydrated cake with a static mixer inserted in the middle, and charging the dehydrated cake into a hopper under a negative pressure from the transport pipeline to reduce the pressure. 2. The dehydrated cake fed into the hopper is again pressure-fed to the rear-stage hopper through the rear-stage transportation pipeline, and the dehydration cake pressure-feeding and depressurization are repeated.
A method for transporting and drying the dehydrated cake described above by a pipe. 3. The suction fan reduces the pressure in the hopper through the intake pipe, and the water vaporized from the dehydrated cake is collected by a mist separator provided in the middle of the intake pipe. The method for transporting and drying the dehydrated cake according to item 2 by a pipe.