JP5913698B1 - Electroosmotic rotary pressure dehydrator - Google Patents

Abstract

Electroosmosis capable of dehydrating an object more efficiently than a conventional rotary pressure dehydrator by a dehydration action by electroosmosis in addition to the original dehydration action as a rotary pressure dehydrator A rotary rotary dehydrator is provided. In an intermediate position in the width direction of the filter chamber (position spaced from each screen on both sides), the filter chamber protrudes from the inner peripheral surface of the outer spacer toward the inner spacer. Alternatively, the metal electrode portion 10 is disposed so as to protrude from the lower surface of the deflector 5 toward the outer spacer 4, the electrode portion 10 is electrically connected to the anode of the power supply device, and the screen 6 is connected to the power source. It was electrically connected to the cathode of the apparatus, and was configured to be able to perform electroosmotic dehydration by applying a DC voltage with the electrode portion 10 as an anode and the screen 6 as a cathode. [Selection] Figure 1

Description

  The present invention relates to a rotary pressure dehydrator that performs dehydration by gradually applying pressure to a processing object as it advances through an annular (C-shaped) filter chamber formed around a rotation axis, and in particular, a voltage is applied. Thus, the present invention relates to a rotary pressure dehydrator capable of generating an electroosmotic flow in a filter chamber and dehydrating a processing object more effectively.

  As shown in Japanese Patent Application Laid-Open No. 2001-113109, a rotary pressure dehydrator (rotary press filter) introduces a liquid processing object (processing stock solution) into an annular filter chamber formed around a rotating shaft. In addition, it is a device that advances a processing object forward by rotating two disk-shaped metal screens and gradually applies pressure to perform a dehydration process, and is widely used for sludge dehydration and the like.

  In addition to the rotary pressure dehydrator, various dehydrators exist as devices used for sludge dehydration and the like. For example, a dehydrator utilizing the principle of electroosmosis (electroosmotic dehydrator) is known. Electroosmosis is a phenomenon in which liquid moves to the cathode side when a voltage is applied to an object in which liquid and solid are mixed. As a conventional electroosmotic dehydrator using this principle, for example, An endless belt comprising a metal rotating drum, a metal belt (endless belt) disposed on the outer side (lower side) of the outer peripheral surface of the lower half, and a filter cloth disposed on the belt. By continuously supplying the object (cake) to the region between the upper filter cloth and the outer peripheral surface of the metal rotating drum, and applying a DC voltage with the metal rotating drum as the anode and the endless belt as the cathode In addition, there are those configured such that an object can be dehydrated by electroosmosis (Japanese Patent Laid-Open No. 2009-45587).

JP 2001-113109 A JP 2004-074066 A JP 2004-291036 A WO2005 / 0777848A1 WO2005 / 102495A1 WO2005 / 105263A1 JP 2006-341258 A JP 2007-326011 A JP 2009-45587 A

  The conventional electroosmosis dehydrator has a unique structure (the filter cloth and the cathode (metal endless belt) are arranged at the radially outer position of the annular filter chamber) so that the principle of electroosmosis can be used most efficiently. The anode (metal rotating drum) is arranged at the radially inner position), mainly in combination with other types of dehydrators (primary dehydrators) arranged in the previous stage (primary dehydrators) It was used as a secondary dehydrator for secondary dehydration of the processing object discharged from the dehydrator, but it must be installed and operated at the same time. There are problems in terms of installation space, installation cost, energy consumption, and the like.

  Therefore, for example, if it becomes possible to perform dehydration using the principle of electroosmosis in a rotary pressurization dehydrator, improvement of the dehydration performance of the rotary pressurization dehydrator can be expected, as well as the installation space and installation as described above. There is a possibility that both problems such as cost and energy consumption can be solved.

  However, the rotary pressure dehydrator is completely different from the electroosmotic dehydrator as described above in that the anode (corresponding to a metal rotating drum) is positioned radially inside the annular filter chamber. Although it is possible to arrange an element), it is extremely difficult to employ a configuration in which a cathode (element corresponding to a metal endless belt) and a filter cloth are arranged at a radially outer position opposite to this. Have difficulty. That is, it is considered that a rotary pressure dehydrator capable of dehydration utilizing the principle of electroosmosis cannot be configured by simply applying a conventional electroosmotic dehydrator configuration to a rotary pressure dehydrator.

  The present invention solves the problems in the prior art as described above, and in addition to the original dehydrating action as a rotary pressurizing dehydrator, the dehydrating action by electroosmosis is more effective than the conventional rotary pressurizing dehydrator. An object of the present invention is to provide an electroosmotic rotary pressure dehydrator capable of efficiently dehydrating an object.

  The electroosmotic rotary pressurization dehydrator according to the present invention has a rotating shaft, an inner spacer, an outer spacer, a deflector, and two metal screens, and is introduced into an annular filter chamber from a stock solution supply port. The object is advanced forward by rotating the two screens, and is gradually compressed and filtered and compressed. The intermediate position in the width direction of the filter chamber (space between each screen on both sides) The metal electrode portion is arranged so as to protrude from the inner peripheral surface of the outer spacer toward the inner spacer, or from the lower surface of the deflector toward the outer spacer, and the electrode Is electrically connected to the anode of the power supply, and the screen is electrically connected to the cathode of the power supply. The electrode is anode and the screen is negative. As by applying a DC voltage, it is characterized in that it is configured to be able to perform the electroosmotic dehydration.

  When this electroosmotic rotary pressure dehydrator is of a type having a vertical restrictor near the cake outlet, the electrode portion projects from the upper surface of the vertical restrictor toward the deflector or the inner spacer. Can be arranged as follows.

  The two screens are preferably electrically connected to the cathode of the power supply device via a rotating shaft and a sliding contact that is always in contact with the rotating shaft. It is preferable that a tapered portion having a uniform inclined surface on the left and right or a curved surface portion having a uniform curved surface on the left and right is formed on the side (the side where the object to be processed first comes in the filter chamber). Moreover, it is preferable to employ | adopt a straight plate-shaped thing with a flat side as an electrode part.

  The electroosmotic rotary pressure dehydrator according to the present invention is more efficient than the conventional rotary pressure dehydrator due to the dehydration action by electroosmosis in addition to the original dehydration action as a rotary pressure dehydrator. The object can be dehydrated. Specifically, by arranging the electrode section in the filter chamber, the cross-sectional area of the filter chamber decreases and the pressure in the filter chamber rises locally, and the increased pressure allows the target to be dehydrated more efficiently than before. Furthermore, electroosmosis can eliminate various problems that can be caused by an increase in the pressure in the filter chamber (decrease in recovery rate, increase in inlet pressure, and clogging of the screen). Compared with a pressure dehydrator, the object can be dehydrated more effectively.

  The conventional electroosmosis dehydrator is combined with other dehydrators (primary dehydrators) arranged in the previous stage (secondary dehydration to dehydrate the processing object discharged from the primary dehydrator after the primary dehydration. The electroosmotic rotary pressure dehydrator according to the present invention has a form in which the electroosmotic dehydrator is incorporated in the rotary pressure dehydrator. It has the same dehydration capacity as a conventional dehydration system composed of a dehydrator and a secondary dehydrator, and can save space, energy and cost.

FIG. 1 is a diagram showing an internal structure of an electroosmotic rotary pressurizing and dehydrating machine (first embodiment) according to the present invention. FIG. 2 is a cross-sectional view of the rotary pressure dehydrator 1 along the line XX shown in FIG. FIG. 3 is a perspective view of the electrode unit 10 shown in FIG. FIG. 4 is a diagram showing an internal structure of another configuration example (second embodiment) of the electroosmotic rotary pressurizing dehydrator according to the present invention. FIG. 5 is a diagram showing an internal structure of another configuration example (third embodiment) of the electroosmotic rotary pressurization dehydrator according to the present invention. FIG. 6 is a diagram schematically showing the situation in the filter chamber 9 of the rotary pressurization dehydrator 1 used in the first embodiment. FIG. 7 is a graph showing test results (relationship between electric power, moisture content difference and recovery rate) of Example 2 of the present invention. FIG. 8 is a diagram schematically showing the situation in the filter chamber 9 of the rotary pressurization dehydrator 1 used in the second embodiment.

  Hereinafter, embodiments of the “electroosmotic rotary pressure dehydrator” of the present invention will be described. FIG. 1 is a diagram showing an internal structure of an electroosmotic rotary pressurization dehydrator (hereinafter simply referred to as “rotary pressurization dehydrator 1”) according to the first embodiment of the present invention, and FIG. FIG. 2 is a cross-sectional view of the rotary pressurization dehydrator 1 along the line XX shown in FIG. 1. As shown in these drawings, the rotary pressure dehydrator 1 of this embodiment includes the basic components of a conventional rotary pressure dehydrator. Common with pressure dehydrator.

  Specifically, the rotary shaft 2, the inner spacer 3, the outer spacer 4, the deflector 5, the two metal screens 6, the casing (not shown), the drive motor, and the like are configured from the stock solution supply port 7 in an annular shape. A (C-shaped) filter chamber 9 (a space formed between the inner spacer 3 and the deflector 5 and the outer spacer 4 and having a rectangular cross section, from the stock solution supply port 7 to the cake outlet 8. The object to be treated (treatment stock solution) is introduced into the space), and the rotary shaft 2, the inner spacer 3 (fixed around the rotary shaft 2), and the screen 6 (fixed on both side surfaces of the inner spacer 3). The object to be processed is moved forward by rotating the filter, the pressure is gradually applied, the filter is compressed, and the dehydrated cake is discharged from the cake outlet 8. It can be.

  A characteristic matter in the rotary pressurization dehydrator 1 of the present embodiment is that an intermediate position in the width direction of the filter chamber 9 (both sides) at the rear stage of the filter chamber 9 (the cake outlet 8 side of the intermediate position of the filter chamber 9). A plurality of metal electrode portions 10 (10A to 10D) are arranged in series in the traveling direction of the object to be processed, at positions spaced from each screen 6). The electrode unit 10 is used as an anode and the screen 6 is used as a cathode so that a DC voltage can be applied. In addition to the original dehydration function as a rotary pressurization dehydrator, In comparison, the object can be dehydrated more efficiently.

  In more detail, each electrode part 10 arrange | positioned in the filter chamber 9 is electrically connected to the anode of the DC power supply device which is not shown in figure, and the screen 6 is the rotating shaft 2 and the rotating shaft 2. Is electrically connected to the cathode of the DC power supply device through a sliding contact (not shown) that is always in contact with the DC power supply.

  When a DC voltage is applied from the DC power supply device, an electroosmosis phenomenon occurs in the filter chamber 9 (region between the electrode unit 10 and the screen 6) using the electrode unit 10 as an anode and the screen 6 as a cathode. The liquid in the object moves toward the screen 6 which is a cathode, and the liquid passes through the eyes of the screen 6 and is discharged to the outside of the filter chamber 9 by the pressure in the filter chamber 9.

  In addition, due to electroosmosis, a repulsive force against the screen 6 acts on the solid content in the vicinity of the screen 6, and the clogging of the screen 6 that has been a problem in the conventional rotary pressurization dehydrator is suppressed. Dehydration can be performed efficiently.

  Furthermore, in the rotary pressure dehydrator 1 according to the present embodiment, the effective width dimension of the filter chamber 9 (and the capacity of the filter chamber 9 is equal to the thickness (lateral width) of the electrode portion 10 at the portion where the electrode portion 10 is disposed. ) Is reduced, and the compressive force applied to the object to be processed passing through the region between the electrode unit 10 and the screen 6 is increased, so that the dewatering efficiency is improved.

  Moreover, in this embodiment, the taper part 11 which has an equal (symmetric) inclined surface on either side in the front side (side in which the process target arrives first in the filter chamber 9) of each electrode part 10 is right. Is formed (see FIG. 3), and the load acting on the electrode unit 10 is reduced at the time of collision with the processing object traveling in the filter chamber 9, and the processing object is evenly distributed to the left and right of the electrode unit 10. As a result, it is possible to prevent the deviation of the pressure acting on the object to be treated, and thus the deviation of the degree of dehydration. In addition, instead of forming the taper part 11, the curved surface of the front side of each electrode part 10 can reduce the load at the time of a collision with a process target object, and can distribute a process target object to right and left equally. A part may be formed.

  Moreover, in this embodiment, as shown in FIG. 1, as the electrode part 10 arrange | positioned in the intermediate position of the width direction of the filter chamber 9, it is trapezoid type and thickness dimension is smaller than the width direction of the filter chamber 9. Although a total of four plate-shaped objects are arranged, the shape and quantity of the electrode portions 10 are not necessarily limited to these, and for example, as shown in FIG. In addition, only two of the four electrode portions 10A to 10D shown in FIG. 1 (for example, only the electrode portions 10A and 10B, or the electrode portions 10A and 10C) may be employed. Or a half-moon shaped plate-like electrode portion may be arranged, and is not limited to a straight plate having a smooth side surface. A corrugated plate or other shapes can also be employed.

  The object to which the electrode portion 10 is fixed is not particularly limited, and may be erected so as to protrude from the inner peripheral surface of the outer spacer 4 toward the inner spacer 3, or from the lower surface of the deflector 5 toward the outer spacer 4. You may install so that it may protrude. In addition, as shown in FIG. 5, a rotary pressure dehydrator of the type in which a vertical restrictor 12 (a back pressure device that compresses the dehydrated cake immediately before discharge by swinging the tip side up and down) at the cake outlet 8 is disposed. 1 may be configured to protrude from the upper surface of the vertical restrictor 12 (or the upper surfaces of the vertical restrictor 12 and the outer spacer 4) toward the deflector 5 or the inner spacer 2.

  Also, multiple electrodes are installed according to the properties of the object to be treated before introduction (solid content concentration, etc.), the properties of the dehydrated cake after discharge (moisture content, etc.), or measured values such as inlet pressure and recovery rate. In order to be able to appropriately select the portion 10 to be energized (for example, only the electrode portions 10A and 10B (or 10A and 10C) of the four electrode portions 10A to 10D shown in FIG. 1 depending on the situation). The electrode portions 10C and 10D (or 10B and 10D) are energized to reduce the effective width of the filter chamber 9, thereby increasing the compressive force on the object to be processed passing therearound. It can also be configured so that it can be operated only as an element for the purpose. In this case, selection and switching of the electrode unit 10 to be energized may be performed manually by an operator, or based on measured values such as moisture content and recovery rate of the dehydrated cake, or moisture content. It is also possible to automatically perform such control target items as in the target range.

  Furthermore, the value of the voltage applied to each electrode unit 10 is individually (for each electrode unit 10), manually, or automatically (based on measured values such as the moisture content and recovery rate of the dehydrated cake, or You may comprise so that control object items, such as a moisture content, can be changed or controlled so that it may exist in a target range.

Here, the result of the test done about the dehydration performance of the electroosmotic rotary pressure dehydrator 1 shown in FIG. 1 will be described as an example. First, an experimental machine (filter chamber diameter: 300 mm, filter chamber width: 50 mm, filter chamber capacity: 2.79 L) of the electroosmotic rotary pressurization dehydrator 1 shown in FIG. And the number of sheets is changed (specifically, the electrode part has a thickness of 10 mm (volume: 37 cm ³ , volume reduction rate: 1.3%) and 25 mm (volume: 92 cm ³ , volume reduction). (Rate: 3.3%) 4 pieces each, and the number of installations was set to 2 or 4), and the sludge of specific conditions was treated as an object to be processed without energizing the electrodes and screen ( Without performing electroosmosis), the dehydration treatment was performed under the following operating conditions, and the moisture content and the like of the discharged dehydrated cake were measured (present inventions 1 to 4).
・ Rotation speed: 1.0 min ⁻¹・ Set pressure: 30 kPa
・ Discharge pressure: 29 kPa ・ Supply amount: 300 L / h

  In addition, by removing the electrode unit 10 from the experimental machine (diameter 300 mm, width 50 mm of the filter chamber 9) of the electroosmotic rotary pressurization dehydrator 1 shown in FIG. The same composition as the pressure dehydrator) is prepared, and the sludge having the same conditions as those of the present invention 1 to 4 is treated, the dewatering process is performed under the same operating conditions, and the moisture content of the discharged dewatered cake, etc. Was measured (comparative example). The measurement results of the present inventions 1 to 4 and the comparative example are shown in the following table.

  From the above test results, in any of the present inventions 1 to 4 in which the electrode part is arranged, the moisture content of the dehydrated cake is lowered as compared with the comparative example in which the electrode part is not arranged even though the current is not conducted. It was confirmed that it was possible. In addition, it is thought that the factor of the moisture content fall is because the filter chamber capacity | capacitance (filter chamber cross-sectional area) decreased by attaching an electrode part in a filter chamber. In addition, it can be seen that if the volume reduction rate of the filter chamber is increased by attaching the electrode part, the moisture content in the dehydrated cake is reduced, but the recovery rate is also lowered. Furthermore, if the electrode part is attached, the inlet pressure increases. It was also confirmed that.

  As shown in FIG. 6, when the cross-sectional area of the filter chamber 9 is reduced by the electrode unit 10, the pressure around the electrode unit 10 is locally larger than the outlet pressure, and the solid content 13 in the processing object is reduced. As a result of passing through the eyes (holes 6a) of the screen 6 and being discharged to the outside of the filter chamber 9, it is considered that the recovery rate is lowered. In the high dehydration type rotary pressure dehydrator disclosed in WO2005 / 105263A1, the cross-sectional area of the filter chamber is reduced by arranging the protrusions on the inner peripheral surface of the outer spacer, and the moisture content is reduced. However, it is considered that problems such as a decrease in the recovery rate and an increase in the inlet pressure may occur.

  Next, in the present invention 1 to 4 used in Example 1, the dehydration treatment was performed while energizing the electrode part and the screen, that is, electroosmosis, and the moisture content and the like of the discharged dehydrated cake were measured. . The results are shown in the following table and FIG.

  From the above test results, it was confirmed that the water content decreased when the power was increased (see FIG. 7). Moreover, it was confirmed that when energization is performed, the inlet pressure is reduced and the recovery rate is improved as compared with the case where energization is not performed (see Tables 1 and 2). Furthermore, when the number of electrode portions is four, it was confirmed that the moisture content and the recovery rate were improved when the power was 2 kWh / h or more.

  When energized, as shown in FIG. 8, the solid content 13 located in the vicinity of the screen 6 moves toward the electrode portion 10 by electroosmosis, and the liquid moves toward the screen 6. Even if the pressure in the filter chamber 9 rises locally due to the reduction of the cross-sectional area of the filter chamber 9 due to the arrangement of the electrode portion 10, the solid content 13 passes through the eyes (holes 6a) of the screen 6. It is considered that the situation of being discharged to the outside of the filter chamber 9 was avoided and the recovery rate was improved. Even if the pressure in the filter chamber 9 rises locally, the liquid in the vicinity of the screen 6 is quickly discharged from the eyes of the screen 6 (holes 6a). As a result of suppressing the problem of clogging, it is considered that the problem of an increase in inlet pressure (see Table 1) has also been improved. Accordingly, even when compared with the high dehydration type rotary pressure dehydrator disclosed in WO2005 / 105263A1, it is possible to expect a significant advantage in terms of dewatering efficiency.

1: Rotary pressure dehydrator,
2: Rotating shaft,
3: Inner spacer,
4: Outer spacer,
5: Deflector,
6: Screen,
6a: hole,
7: Stock solution supply port,
8: Cake exit,
9: Filter chamber
10, 10A-10D: electrode part,
11: Tapered portion,
12: Vertical restrictor,
13: Solid content

Claims (5)

A rotating shaft, an inner spacer, an outer spacer, a deflector, and two metal screens fixed to both side surfaces of the inner spacer , and the inner spacer, the deflector, and the outer spacer from the stock solution supply port The processing object introduced into the annular filter chamber formed between the two screens is advanced forward by rotating the two screens, and the pressure is gradually increased. In the dehydrator
At an intermediate position in the width direction of the filter chamber, a metal is used so as to protrude from the inner peripheral surface of the outer spacer toward the inner spacer, or from the lower surface of the deflector toward the outer spacer. Are arranged,
The electrode unit is electrically connected to the anode of the power supply device, the screen is electrically connected to the cathode of the power supply device, and the electrode unit is used as an anode and the screen is used as a cathode to apply a DC voltage, An electroosmotic rotary pressure dehydrator characterized by being configured to perform electroosmotic dehydration. A rotating shaft, an inner spacer, an outer spacer, a deflector, two metal screens fixed to both side surfaces of the inner spacer , and a vertical restrictor, and the inner spacer and the deflector from the stock solution supply port ; The object to be treated introduced into the annular filter chamber formed between the outer spacer and the outer spacer is advanced forward by rotating the two screens, and is gradually compressed and filtered and compressed. In the rotary pressure dehydrator
At an intermediate position in the width direction of the filter chamber, a metal electrode portion is disposed so as to protrude from the upper surface of the vertical restrictor toward the deflector or the inner spacer,
The electrode unit is electrically connected to the anode of the power supply device, the screen is electrically connected to the cathode of the power supply device, and the electrode unit is used as an anode and the screen is used as a cathode to apply a DC voltage, An electroosmotic rotary pressure dehydrator characterized by being configured to perform electroosmotic dehydration.   The said two screens are electrically connected to the cathode of a power supply device through the said rotating shaft and the sliding contact which always contacts a rotating shaft. Item 3. The electroosmotic rotary pressure dehydrator according to Item 2.   The taper part which has an equal inclined surface on either side in the front side of the said electrode part, or the curved surface part which has an equal curved surface on either side is formed in any one of Claims 1-3 characterized by the above-mentioned. The electroosmotic rotary pressure dehydrator as described.   The electroosmotic rotary pressure dehydrator according to any one of claims 1 to 4, wherein the electrode part is a straight plate having a flat side surface.

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