JP4252516B2 - Method and apparatus for cleaning and dewatering slurry - Google Patents

Description

  The present invention relates to a method and an apparatus for washing and dewatering a slurry for recovering valuable materials contained in the slurry or removing harmful substances and obstacles.

In order to recover valuable materials contained in the slurry and remove harmful substances and obstacles, it is widely practiced to wash the slurry and then squeeze it to remove excess moisture. For example, in order to use incineration ash as a raw material for cement, incineration ash is put into water and stirred to form a slurry, which is washed and dehydrated using multiple washing tanks and multiple dehydrators, and chlor in the incineration ash. Methods for removing ions are known. (Patent Document 1)
JP 2003-211129 A

However, this type of conventional washing and dehydration method requires the use of a plurality of washing tanks and a plurality of dehydrators, which increases the installation space of the apparatus, and a large amount of washing water is required for washing through a plurality of processes. I was consuming. In addition, since the washing and dehydration are repeated, the operation management for balancing the amount of water is complicated.
The present invention has been made in view of the above points, and an object of the present invention is to effectively wash and dehydrate the slurry using a filter press known as a slurry dewatering apparatus.

That is, the present invention
A filter press comprising a filter chamber defined at least in part by a filter cloth, means for supplying slurry to the filter chamber, and pressure means for compressing the filter chamber by applying pressure to the filter chamber from the outside. In the slurry dehydration method using
A filtration step in which the slurry is supplied into the filter chamber at a predetermined pressure and filtered;
A washing step of supplying washing water into the filter chamber at a pressure higher than the predetermined pressure after the filtration step, and washing the filtration residue in the filter chamber;
There is provided a method for washing and dehydrating a slurry using a filter press, comprising: a pressurizing step of pressurizing a filter chamber by a pressurizing means after the cleaning step, and pressing the cleaned filtration residue in the furnace chamber.

  Specifically, in this washing and dehydrating method, it is preferable to repeat the filtration step and the washing step a plurality of times alternately.

Furthermore, the present invention provides
A filter press comprising a filter chamber defined at least in part by a filter cloth, a pressurizing chamber for compressing the filter chamber by applying pressure from the outside to the filter chamber;
Slurry pressure supply means for supplying the slurry at a predetermined pressure into the filter chamber and filtering the slurry; and
Wash water pressure supply means for supplying wash water to the filter chamber at a pressure higher than the predetermined pressure, and for washing the filtration residue in the filter chamber;
In order to compress the filter chamber and squeeze the filtration residue in the filter chamber, compressed water supply means for supplying compressed water to the pressure chamber;
The filter press apparatus characterized by having is provided.

  Specifically, the cleaning and dehydrating apparatus may include a control unit that alternately operates the slurry pressure supply unit and the cleaning water pressure supply unit a plurality of times, and then operates the compressed water supply unit. preferable.

Specifically, the slurry pressure supply means includes a slurry storage tank, a slurry supply line for supplying slurry from the slurry storage tank to the filter chamber, a first on-off valve provided in the slurry supply line, and a first A pump,
The cleaning water pressure supply means includes a water storage tank, a cleaning water supply line for supplying water for slurry cleaning from the water storage tank to the filter chamber, a second on-off valve provided in the cleaning water supply line, and a second 2 pumps,
The compressed water supply means includes a water storage tank, a compressed water supply line that supplies water for compressing and compressing the filter chamber to the pressurized chamber, a third on-off valve provided in the compressed water supply line, and a second 3 pumps.

Furthermore, the 1st on-off valve in a slurry supply line is provided in the upstream rather than the 1st pump,
A second on-off valve in the washing water supply line is provided upstream of the second pump;
The downstream side of the first pump of the slurry supply line and the downstream side of the second pump of the cleaning water supply line may be integrally connected to communicate with the filter chamber.

  In the present invention, the filtration, washing and squeezing and dewatering of the slurry are performed using a single filter press, so that the installation space is greatly increased compared to the conventional washing and dehydrating apparatus using a plurality of washing tanks and a plurality of dehydrators. Can be reduced.

  In addition, since a plurality of processes can be continuously performed in the filter press, complicated processes such as re-dissolution of the dehydrated cake in the washing water tank and re-washing of the slurry that has been dissolved in the conventional washing dehydration apparatus are required. Work can be omitted, and the amount of water required for re-dissolution and re-washing can be reduced.

  Furthermore, by supplying the water for washing at a higher pressure than when the slurry is fed into the filter chamber, the filtration residue solidified by filtration can be quickly crushed and washed. Enables cleaning work.

  Hereinafter, embodiments of a method for washing and dehydrating a slurry according to the present invention and a filter press device used in the method will be described with reference to the accompanying drawings.

  FIG. 1 shows an outline of a filter press apparatus 10 according to the present invention. That is, the filter press apparatus 10 cleans or squeezes the filter press 12, the slurry supply means 14 for supplying slurry to the filter press 12, and the slurry supplied into the filter press. And pressurized water supply means 16 for supplying pressurized water for the purpose.

  The filter press 12 includes a plurality of filter dewatering units for receiving and squeezing the slurry, as in a general case, and each unit includes a filter frame 18 and a filter frame as shown in FIG. A filter cloth 22 that is provided in the filter chamber 20 and that is provided between the filter cloth 22 and the inner surface of the filter frame 18, and that forms a pressurizing chamber 24 between the filter frame 18 and the inner surface of the filter frame 18. 26. Concavities and convexities 26-1 are formed on the surface of the diaphragm 26 in contact with the filter cloth 22, so that liquid exiting from the filter chamber 20 through the filter cloth 22 can flow between the diaphragm 26 and the filter cloth 22. .

  The slurry supply unit 14 includes a slurry tank 30 that stores the slurry S, and a slurry supply line 32 that supplies the slurry S from the slurry tank 30 to the filter chamber 20. The slurry supply line 32 is provided with an on-off valve 34 and a pump 36 from the upstream side.

The pressurized water supply means 16 includes a compressed water supply means 44 having a water storage tank 40 and a compressed water supply line 42 for supplying pressurized water W for compressing and compressing the filter chamber 20 to the pressure chamber 24. The compressed water supply line 42 is provided with an on-off valve 46 and a pump 48 from the upstream side.
In the filter press device 10 according to the present invention, the supply of washing water branched from the compressed water supply line 42 to supply the pressurized water supply means 16 with pressurized water for washing the filtration residue in the filter chamber 20 to the filter chamber. Washing water supply means 54 having a line 52 is provided. The cleaning water supply line 52 is provided with a pump 56 and an opening / closing valve 58.

  In the illustrated example, the slurry supply line 32 is connected to the cleaning water supply line 52 on the downstream side of the on-off valve 58.

  When washing and dehydrating the slurry S using this filter press apparatus, first, the on-off valve 34 is opened and the other on-off valves 46 and 58 are closed, and the slurry S is supplied into the filter chamber 20 by a pump 36 at a predetermined pressure. To do. The slurry supplied into the filter chamber 20 is filtered by the filter cloth 22 by pressurization with a pump, and the slurry remaining in the filter chamber 20 is in a state in which the solid content is high.

  Next, the on-off valve 34 is closed and the on-off valve 58 is opened, and the pressurized water W is supplied to the filter chamber 20 by the pump 56 at a pressure higher than the slurry supply pressure by the pump 36. The slurry residue left in the filter chamber 20 is rapidly stirred by the high-pressure pressurized water, and harmful substances left in the slurry residue flow out to the outside of the filter cloth together with water. The residue is washed.

  Further, as the next step, the on-off valve 58 is closed and the on-off valve 46 is opened, and pressurized water is supplied into the pressurizing chamber 24 by the pump 46 at a high pressure. The pressurized water supplied into the pressurizing chamber causes the diaphragm 26 to swell toward the filter chamber, whereby the slurry residue in the filter chamber 20 is squeezed to form a cake. The cake is discharged to the outside by opening the filter frame 18.

  The supply of the slurry to the filter chamber 20 and the cleaning of the slurry residue in the filter chamber are preferably repeated several times in order to increase the filter cleaning effect.

  In the figure, reference numeral 60 denotes a controller for sequence-controlling the on-off valves 34, 46, 58 and the pumps 36, 48, 56 in a predetermined order in order to perform the slurry supply filtration, slurry residue washing, and slurry residue pressing.

Hereinafter, the Example which performed the operation | work which removes the chloro ion contained in soybean meal using the filter press apparatus which concerns on this invention is described.

  The soybean meal slurry first treated with hydrochloric acid was stored in the slurry storage tank 30. At this time, the chlorine ion concentration of the soybean meal slurry was 18.2 gCl / kg-DS, and the slurry concentration was about 5%.

  First, the on-off valves 46 and 58 are closed, the on-off valve 34 is opened, and 150 liters of soybean meal slurry is supplied from the slurry storage tank 30 into the filter chamber 20 of the filter press 12 at a pressure of 0.6 MPa. After that, the on-off valve 34 is closed and the on-off valve 58 is opened, and 89 liters of washing water, which is 3.6 times the filtration chamber volume of 25 liters, is injected by the pump 56 of the washing water supply line 52 at a pressure of 0.8 MPa. The filter residue in the filter chamber was washed. Next, the on-off valve 58 is closed, the on-off valve 46 is opened, and pressurized water is supplied into the pressurizing chamber 24 at a pressure of 1.6 MPa by the pump 48, the filter chamber is compressed, and the filtration residue washed in the filter chamber is removed. It was pressed to obtain a dehydrated cake of soybean meal.

  As a result of the measurement, this dehydrated cake has a water content of 58.5%, a chloroion concentration of 2.3 gCl / kg-DS, and a numerical value less than the target value of chloroion concentration of 2.3 gCl / kg-DS. I understood.

  Thus, in the present invention, since it can be washed and dehydrated with a single filter press, complicated operations such as re-dissolution of the dehydrated cake in the washing water tank and re-washing work required in the conventional apparatus are required. In addition, a significant amount of water was saved. In addition, not only chloro ions but also dehydration-inhibiting substances may be removed during washing, and the moisture content of the cake after dehydration can be reduced as described above.

  Moreover, the washing time could be shortened by making the water supply pressure for washing the filter chamber higher than the slurry supply pressure. When the cleaning water pressure is set to 0.6 MPa, which is about the same as the slurry supply pressure, the time required for cleaning is about 7 minutes, compared with the result of setting the cleaning water supply pressure to 0.8 MPa in this example. The time required for washing could be about 3 minutes and less than 1/2.

  In the second example, the soybean meal slurry was divided into 50 liters in three portions, press-fitted into a filter press, and washed each time. The amount of washing water was 25 liters for the first time, 30 liters for the second time, and 34 liters for the third time. After washing, the water content of the dehydrated cake that had been pressed and dehydrated was 56.2%, and the chloroion concentration was 2.0 g Cl / kg-DS.

  That is, when the slurry was dividedly injected and washed, the moisture content of the cake was lowered and the chloro ion concentration was also lowered, resulting in a higher washing effect.

  Also, the time required for filtration was 15 minutes for batch cleaning, but was shortened to 12 minutes for divided cleaning, and the filtration speed of the filter press was improved. In this case, the amount of washing water may be the same amount, or the amount of water may be decreased sequentially, but it is preferable to gradually increase as in the above embodiment. Further, it is preferable that the amount of washing water at one time is at least the volume of the filter chamber.

  In the above embodiment, water is used to wash the slurry residue, but hot water may be used instead of water, and the slurry may be heated and supplied. In addition, a heat source device may be provided and heated while supplying slurry or water, and the filtrate discharge line may be placed under vacuum with a vacuum device to promote dehydration.

It is a figure which shows the outline | summary of the filter press apparatus which concerns on this invention. It is a figure which shows an example of the filtration pressing unit of the filter press used with the filter press apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Filter press apparatus 12 Filter press 14 Slurry supply means 16 Pressurized water supply means 18 Filter frame 20 Filter chamber 22 Filter cloth 24 Pressurization chamber 26 Diaphragm 26-1 Concavity and convexity 30 Slurry tank 32 Slurry supply line 34 On-off valve 36 Pump 40 Water storage tank 42 Pressed water supply line 44 Pressed water supply means 46 On-off valve 48 Pump 52 Wash water supply line 54 Wash water supply means 56 Pump 58 Open / close valve 60 Controller

Claims (6)

A filter press comprising a filter chamber defined at least in part by a filter cloth, means for supplying slurry to the filter chamber, and pressure means for compressing the filter chamber by applying pressure to the filter chamber from the outside. In the slurry dehydration method using
A filtration step in which the slurry is supplied into the filter chamber at a predetermined pressure and filtered;
A washing step of supplying washing water into the filter chamber at a pressure higher than the predetermined pressure after the filtration step, and crushing and washing the filtration residue in the filter chamber;
A method for cleaning and dehydrating a slurry using a filter press, comprising: a pressurizing step of pressurizing a filter chamber by a pressurizing means after the cleaning step, and pressing the cleaned filtration residue in the furnace chamber.   The washing of the slurry according to claim 1, wherein the filtration chamber is pressurized by a pressurizing means after the filtration step and the washing step are alternately repeated a plurality of times, and the washed filtration residue in the filtration chamber is squeezed. Dehydration method. A filter press comprising a filter chamber defined at least in part by a filter cloth, a pressurizing chamber for compressing the filter chamber by applying pressure from the outside to the filter chamber;
Slurry pressure supply means for supplying the slurry at a predetermined pressure into the filter chamber and filtering the slurry; and
Wash water pressure supply means for supplying wash water to the filter chamber at a pressure higher than the predetermined pressure, and pulverizing and washing the filtration residue in the filter chamber;
In order to compress the filter chamber and squeeze the filtration residue in the filter chamber, compressed water supply means for supplying compressed water to the pressure chamber;
Control means for controlling the operation of slurry pressure supply, wash water pressure supply, wash water pressure supply and compressed water supply ;
The filter press apparatus characterized by having. The control means according to claim 3, wherein the slurry pressure supply means and the washing water pressure supply means are alternately operated a plurality of times, and then the compressed water supply means is operated.
The filter press apparatus characterized by having. The slurry pressure supply means has a slurry storage tank, a slurry supply line for supplying slurry from the slurry storage tank to the filter chamber, and a first on-off valve and a first pump provided in the slurry supply line. ,
The cleaning water pressure supply means includes a water storage tank, a cleaning water supply line for supplying water for slurry cleaning from the water storage tank to the filter chamber, a second on-off valve provided in the cleaning water supply line, and a second 2 pumps,
The compressed water supply means includes a water storage tank, a compressed water supply line that supplies water for compressing and compressing the filter chamber to the pressurized chamber, a third on-off valve provided in the compressed water supply line, and a second 5. The filter press device according to claim 3, comprising three pumps. A first on-off valve in the slurry supply line is provided upstream of the first pump;
A second on-off valve in the washing water supply line is provided upstream of the second pump;
The downstream side of the first pump of the slurry supply line and the downstream side of the second pump of the washing water supply line are integrally connected and communicated with the filter chamber. Filter press device.

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