JP4586581B2 - Dephosphorization device - Google Patents

Description

  The present invention relates to a dephosphorization apparatus.

  The water to be treated is blown into one of the dephosphorization devices for removing phosphate ions contained in the water to be treated by blowing air in the presence of magnesium ions and ammonium ions to the water to be treated supplied from the lower part of the device. There is a device for precipitating a phosphoric acid compound and dephosphorizing it, and discharging this supernatant liquid as treated water (see, for example, Patent Documents 1 to 5).

In such a dephosphorization apparatus, the water to be treated is supplied into the reaction vessel from the lower part of the reaction vessel, and the water to be treated is stirred by air in the reaction vessel to promote the precipitation of the phosphate compound. Then, the precipitated phosphate compound is settled to the lower part of the reaction vessel by its own weight, the phosphate compound is extracted from the lower part of the reaction vessel, and the supernatant in the reaction vessel from which the phosphate ions have been removed is treated from the upper part of the reaction vessel. It is discharged as water.
Japanese Patent Laid-Open No. 8-252584 JP-A-9-206760 JP-A-11-309464 JP-A-8-24875 Japanese Patent Laid-Open No. 10-263769

  However, in the conventional dephosphorization apparatus, the granulation time of the phosphate compound precipitated in the reaction vessel is not particularly defined, and the particle size of the extracted phosphate compound varies. The phosphoric acid compound deposited and granulated in the dephosphorization apparatus can be recycled as, for example, plant fertilizer. However, if the particle size of the extracted phosphoric acid compound varies, its value as a product Will fall. For this reason, the technique which makes the particle size of the phosphoric acid compound extracted from a dephosphorization device constant is desired. Moreover, when using a phosphoric acid compound as a product, it is preferable that the phosphoric acid compound has a certain size (for example, 1 to 2 mm), but in a conventional dephosphorization apparatus, Since the granulation time of the precipitated phosphate compound is not sufficient, the phosphate compound having a desired particle size could not be stably extracted.

  The present invention has been made in view of the above-described problems, and an object thereof is to stably extract a phosphate compound having a desired particle size.

  In order to achieve the above object, in the present invention, as a first means, by blowing air in the presence of magnesium ions and ammonium ions into the water to be treated which contains phosphate ions and is supplied from the lower part of the apparatus, A dephosphorization device for precipitating a phosphate compound from the water to be treated and dephosphorizing it, and discharging the supernatant liquid as treated water from the upper part of the apparatus, which is disposed at the bottom of the apparatus and contains the phosphate compound inside. A granulation vessel for granulation, and a reaction that is arranged on the granulation vessel in communication with the granulation vessel and precipitates the phosphate compound by blowing the air into the water to be treated inside. A structure in which the water to be treated is supplied to the granulation container at a flow rate at which a phosphoric acid compound having a desired particle size floats at a desired height in the granulation container. To use.

  As a second means, in the first means, by defining the container diameter of the granulation container, a flow rate at which a phosphoric acid compound having a desired particle diameter floats at a desired height in the granulation container is achieved. Adopting a configuration to do.

  As a third means, in the first or second means, the horizontal section of the granulation container is circular, and the water to be treated is supplied into the granulation container from the tangential direction of the granulation container. Adopting a configuration to do.

  As a fourth means, in any one of the first to third means, a configuration is adopted in which a flow rate adjusting means for adjusting the flow rate of the water to be treated in the granulation vessel is further provided.

  As a fifth means, in the fourth means, the flow rate adjusting means is a pump that circulates a part of the water to be treated in the reaction vessel and supplies it to the granulation vessel. .

  As a sixth means, in any one of the first to fifth means, a recovery container that is arranged on the reaction container in communication with the reaction container and collects the air from the treated water inside. A configuration of providing is adopted.

  As a seventh means, in the sixth means, the recovery container is disposed on the recovery unit for recovering the air from the treated water, and the air is recovered by the recovery unit. In addition, a configuration is adopted in which a storage section for storing the water to be treated is provided, and at least the cross-sectional area of the recovery section in the recovery container is set wider than the cross-sectional area of the reaction container.

  As an eighth means, in the sixth or seventh means, the water to be treated collected together with the air is separated from the air, and the water to be treated after separation is separated into the granulation vessel and the reaction vessel. A configuration is adopted in which a separation / circulation means is provided.

  As a ninth means, in the eighth means, the separation / circulation means raises the air collected in the collection container together with a part of the treated water and collects the riser pipe, together with the air A gas-liquid separator that separates the recovered water to be treated and the air; and a downer pipe that supplies the treated water after separation to the granulation vessel and the reaction vessel. A configuration is adopted in which the height on the surface of the water to be treated is set so that the air does not leak from the collection container.

  As a tenth means, in any one of the means 6 to 9, a configuration is adopted in which a cross section of the collection container is set in a rectangular shape.

  According to the present invention, since the water to be treated is supplied to the granulation vessel at a flow rate at which the phosphoric acid compound having a desired particle size floats at the desired height in the granulation vessel, the phosphate compound is removed from the desired height. By extracting, a phosphate compound having a desired particle diameter can be always stably extracted. Moreover, since the phosphoric acid compound having a particle size smaller than the desired particle size is present in the granulation vessel until the desired particle size is obtained, the phosphoric acid compound precipitated in the reaction vessel becomes sufficiently large. Until it becomes possible to granulate sufficiently.

  Hereinafter, an embodiment of a dephosphorization apparatus according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to facilitate recognition of each member.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a dephosphorization apparatus 1 according to the present embodiment. As shown in this figure, the dephosphorization apparatus 1 according to the present embodiment includes a granulation container 2, a reaction container 3, and a recovery container 4.

The granulation container 2 is a container set in a cylindrical shape, and is disposed as the bottom of the dephosphorization apparatus 1. Then, in the interior of the granulating vessel 2, granulation of the phosphoric acid ion _(HPO ^{4 2-)} phosphoric acid compounds precipitated from the water to be treated X containing (MgNH ₄ PO ₄₎ is performed. Moreover, in order to supply the to-be-processed water X to the lower part of this granulation container 2, the extraction line 27 for extracting the phosphoric acid compound granulated in the granulation container 2, and the granulation container 2 To-be-treated water supply line 22 is connected. In the dephosphorization apparatus 1 of the present embodiment, the container diameter of the granulation container 2 is such that the flow rate of the water X to be treated supplied into the granulation container 2 is the desired particle diameter. The height at which the acid compound floats is defined to be the height (desired height) of the extraction line 27. That is, the container diameter of the granulation container 2 is specified in order to obtain a flow rate at which a phosphate compound having a desired particle diameter (for example, 1 to 2 mm) floats at the height of the extraction line 27. In addition, by controlling the flow rate of the water to be treated X supplied to the granulation container 2, it is possible to obtain a flow rate at which a phosphate compound having a desired particle size floats at the height of the extraction line 27. The treated water X is continuously supplied from the outside at an approximately constant flow rate, and the dephosphorization apparatus 1 needs to continuously treat the treated water X at the constant flow rate. For this reason, it is more stable to obtain the above-mentioned flow rate by regulating the container diameter of the granulation vessel 2 than to obtain the above-mentioned flow rate by defining the flow rate of the to-be-treated water X. Processing can be performed.

The reaction vessel 3 is arranged on the granulation vessel 2 in communication with the granulation vessel 2. Similarly to the granulation vessel 2, the reaction vessel 3 is a vessel set in a cylindrical shape, and the vessel diameter of the reaction vessel 3 is larger than the vessel diameter of the granulation vessel 2. The granulation container 2 is arranged coaxially. And in this reaction container 3, the phosphoric acid compound is precipitated from the to-be-processed water X by blowing the air Y with respect to the to-be-processed water X, and the dephosphorization process of the to-be-processed water X is performed.
Inside the reaction vessel 3, a stirring assist pipe 5 for stirring the water to be treated X and the air Y in the reaction vessel 3 is disposed. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1. As shown in this figure, the stirring assisting tube 5 is disposed coaxially with the reaction vessel 3 and is about half the diameter of the reaction vessel 3. The cylindrical tube has a diameter. Further, the lower end 5a of the stirring assisting tube 5 is separated from the granulation container 2 by 80 to 100 cm, and the upper end 5b is separated from the collection container 4 described later by 80 to 100 cm. That is, the reaction vessel 3 has a double tube structure of the reaction vessel main body and the stirring assisting tube 5. In addition, the stirring assistance pipe | tube 5 is supported by connecting with the reaction container main body by the support part not shown.
Further, as shown in FIGS. 1 and 2, a plurality of air diffusers 6 that are arranged vertically below the stirring assisting tube 5 and blow air Y toward the inside of the stirring assisting tube 5 inside the reaction vessel 3. The air Y is blown into the reaction vessel 3 by supplying the air Y to the air diffuser 6 via the air injection line 21. In addition, it is preferable that the ejection angle of the air Y of the air diffuser 6 is set so that almost all of the air Y ejected from the air diffuser 6 is blown into the stirring assist pipe 5.

  A treated water supply line 22 is also connected to the lower part of the reaction vessel 3, and the treated water X is also supplied into the reaction vessel 3 through the treated water supply line 22. And the to-be-processed water supply line 22 connected to the granulation container 2 and the to-be-processed water supply line 22 connected to the reaction container 3 are a tangential direction in planar view with respect to the granulation container 2 and the reaction container 3. It is connected. The reaction vessel 3 is connected to a sodium hydroxide supply line 23 for supplying sodium hydroxide (NaOH) into the reaction vessel 3. By supplying sodium hydroxide into the reaction vessel 3 through the sodium hydroxide supply line 23, the pH (7.7) suitable for the water to be treated X in the reaction vessel 3 to precipitate the phosphate compound. To 9.5, preferably 8.1).

  The recovery container 4 is arranged on the reaction container 3 so as to be connected to the reaction container 3, and the cross section is set to a substantially square shape (rectangular shape) and is wider than the cross section (cross sectional area) of the reaction container 3. Container. The recovery container 4 is disposed on the recovery unit 41 for recovering the air Y supplied to the water to be treated X in the reaction container 3, and the air Y is recovered by the recovery unit 41. The storage part 42 which stores the to-be-processed water X was comprised.

  FIG. 3 is a perspective view of the collection unit 41. As shown in this figure, the collection unit 41 includes an air collection unit 43 and a gas hood 44. The gas hood 44 is disposed from the air collecting part 43 to the inner wall surface of the collection container 4. In the present embodiment, the gas hood 44 is disposed in a plurality of stages and in four stages in the horizontal direction. The air collecting part 43 is a box having a hollow inside, and an opening 45 corresponding to each gas hood 44 is formed. And the air Y supplied with respect to the to-be-processed water X is collected by the gas hood 44 of the collection | recovery part 41 comprised in this way, The collected air Y is with a part of to-be-processed water X. The air is collected in the air collecting unit 43 through the opening 45. Here, in the dephosphorization apparatus 1 which concerns on this embodiment, the cross-sectional shape of the collection container 4 is made into substantially square. For this reason, it is possible to secure a sufficient area for collecting the air Y, to make the lengths of all the gas hoods 44 the same, and to collect the air Y uniformly in the entire plan view of the collection container 4. be able to. For this reason, it is possible to prevent the air Y from leaking from the collection unit 41, and it is possible to prevent the air Y from leaking to the storage unit 42.

  Returning to FIG. 1, a riser pipe 7 is connected to the upper portion of the air collecting section 43, and this riser pipe 7 is connected to a gas-liquid separator 8 disposed above the collection container 4. As will be described in detail later, the height of the upper portion 71 of the riser pipe 7 from the collection container 4, that is, the height of the upper portion 71 from the water surface of the treated water X is set to a height at which the air Y does not leak from the gas hood 44. Has been. The gas-liquid separator 8 of the riser pipe 7 separates the air Y and the water to be treated X supplied through the riser pipe 7, exhausts the air Y through the ventilation line 24, The liquid is supplied to a downer tube 9 connected to the liquid separator 8. The downer pipe 9 is branched into two pipes 91 and 92 at an intermediate position, the pipe 91 is connected to the reaction vessel 3, and the tube 92 is connected to the granulation vessel 2. The pipe 91 is obliquely connected to the reaction vessel 3 so as to supply the treated water X into the reaction vessel 3 from above to below, and is connected above the lower end 5 a of the stirring assisting tube 5. Yes. As shown in FIG. 2, the tube 91 is connected to the reaction vessel 3 from the tangential direction in plan view. Further, a pump 10 (flow rate adjusting means) for adjusting the flow rate of the water to be treated X flowing into the pipe 92 and a flow meter 11 for measuring the flow rate of the pipe 92 are installed. The pump 10 circulates and supplies a part of the water to be treated X supplied through the riser pipe 7, that is, a part of the water to be treated X in the reaction vessel 3 to the granulation vessel 2. Therefore, the flow rate of the water to be treated X in the granulation vessel 2 can be adjusted by the flow rate of the water to be treated X supplied from the pump 10.

Further, in order to supply magnesium (Mg) and ammonium (NH ₄ ) to the pH meter 12 for measuring the pH of the water to be treated X and the water to be treated X in the middle part of the downer pipe 9 before branching. Are connected to the magnesium / ammonium supply line 25. Based on the measurement result of the pH meter 12, sodium hydroxide is appropriately supplied into the reaction vessel 3 from the sodium hydroxide supply line 23 described above.
In addition, a treated water discharge line 26 is connected to the upper part of the reservoir 42 for discharging the supernatant Z collected in the reservoir 42 as treated water to the outside of the dephosphorization apparatus 1. In addition, a plurality of spray nozzles 46 for ejecting water or the like toward the supernatant liquid Z collected in the storage unit 42 are installed in the upper part of the storage unit 42.

  In the present embodiment, the separation / circulation means in the present invention includes the riser pipe 7, the gas-liquid separator 8, the downer pipe 9, the pipes 91 and 92, and the pump 10.

  Next, operation | movement of the dephosphorization apparatus 1 which concerns on this embodiment comprised as mentioned above is demonstrated.

First, the water to be treated X supplied to the lower part of the granulation vessel 2 and the reaction vessel 3 via the water to be treated supply line 22 is reacted inside the reaction vessel 3 via the air injection line 21 and the air diffuser 6. 3 is mixed with the air Y blown into the interior 3 and rises in the dephosphorization apparatus 1. Of the to-be-treated water X rising in the reaction vessel 3, the to-be-treated water X that has flowed into the stirring assistance pipe 5 is discharged from the upper end 5b of the stirring assistance pipe 5 and the rising flow N1 and the stirring assistance. A flow N2 that circulates outside the tube 5 and flows downward between the stirring assisting tube 5 and the main body of the reaction vessel 3 is divided. Therefore, a vertical swirl flow S as shown in FIG. 1 is formed in the reaction vessel 3, and the water to be treated X and the air Y are agitated. As will be described later, the water to be treated X supplied with magnesium ions and ammonium ions is supplied into the reaction vessel 3 through the pipe 91, so that the phosphate compound is contained in the water to be treated X in the reaction vessel 3. It is deposited.
And in the dephosphorization apparatus 1 which concerns on this embodiment, since the to-be-processed water X and the air Y in the reaction container 3 are stirred by the stirring assistance pipe 5, precipitation of a phosphoric acid compound is accelerated | stimulated, and to-be-processed water The removal efficiency of phosphate ions contained in X can be improved. In the reaction vessel 3, a phosphoric acid compound having a particle size of about 60 μm is deposited.

Here, in the dephosphorization apparatus 1 according to the present embodiment, the air diffuser 6 is disposed vertically below the stirring assist pipe 5 and is disposed so as to blow air toward the inside of the stirring assist pipe 5. For this reason, the air Y supplied from the air diffuser 6 enters the inside of the stirring assist pipe 5 and promotes the rise of the treated water X inside the stirring assist pipe 5. Further, since almost all of the air Y ejected from the air diffuser 6 is set to be blown into the stirring assisting pipe 5, almost all the air Y ejected from the air diffuser 6 is stirred. The air Y does not interfere with the flow N2 that flows downward between the stirring assist pipe 5 and the main body of the reaction vessel 5. Therefore, the swirl flow S having a strong flow can be formed, and the precipitation of the phosphoric acid compound can be further promoted.
Further, in the dephosphorization apparatus 1 according to the present embodiment, the container diameter of the reaction container 3 is larger than the container diameter of the granulation container 2, and the reaction container 3 and the granulation container 2 are coaxially arranged. Has been placed. For this reason, the to-be-processed water X rising toward the reaction vessel 3 from the granulation vessel 2 rises mainly in the central portion of the reaction vessel 3. Accordingly, it is possible to prevent the flow N2 flowing downward between the stirring assist pipe 5 and the main body of the reaction vessel 3 from being hindered.

  Subsequently, the to-be-treated water X discharged from the upper end 5 b of the stirring assist pipe 5 rises to the collection unit 41 of the collection container 4 while being mixed with the air Y. And the to-be-processed water X which rose to the collection | recovery part 41 collects the air Y by the collection | recovery part 41. In addition, the phosphoric acid compound contained in the to-be-processed water X hits the gas hood 44 of the collection | recovery part 41, and settles with dead weight. And the to-be-processed water X from which the air Y was collect | recovered and from which the phosphate ion was removed overflows from the upper part of the storage part 42 as the supernatant liquid Z, and the dephosphorization apparatus 1 as treated water through the treated water discharge line 26 Is discharged outside. Note that a plurality of spray nozzles 46 that eject water or the like toward the supernatant liquid Z are arranged in the upper part of the reservoir 42. For this reason, the foam which generate | occur | produces in the surface layer of the supernatant liquid Z can be defoamed, and the overflow of the supernatant liquid Z from the storage part 42 can be performed smoothly. The spray angle of the spray nozzle 46 is preferably about 120 °. As a result, for example, the number of spray nozzles 46 can be reduced as compared with the case where spray nozzles having a jet angle of 90 ° are installed.

Here, in the dephosphorization apparatus 1 according to the present embodiment, the cross-sectional area of the recovery container 4 is made wider than the cross-sectional area of the reaction container 3 as described above. For this reason, the rising flow rate of the supernatant liquid Z is slower than the rising flow rate of the water to be treated X in the reaction vessel 3. Therefore, even if the phosphate compound passes through the collection unit 41, it is possible to prevent the phosphate compound from reaching the upper part of the storage unit 42.
In addition, since the cross-sectional area of the recovery container 4 is larger than the cross-sectional area of the reaction container 3 and the cross-section of the recovery container 4 is rectangular, the air Y leaks from the recovery unit 41 as described above. Can be deterred. For this reason, it is possible to suppress an increase in the ascending flow rate of the supernatant liquid Z due to the air Y leaked from the recovery unit 41, and it is also possible to suppress the phosphate compound from reaching the upper part of the storage unit 42.
Therefore, according to the dephosphorization apparatus 1 which concerns on this embodiment, since it can suppress that a phosphate compound reaches | attains to the upper part of the storage part 42, it suppresses that a phosphate compound mixes in process water. Is possible.

Further, the phosphate compound that precipitates due to its own weight finally settles into the granulation vessel 2. And in the dephosphorization apparatus 1 of this embodiment, the phosphoric acid compound with the desired particle size (for example, 1-2 mm) floats in the height of the extraction line 27 in the flow rate of the to-be-processed water X in the granulation container 2. The flow rate is For this reason, the phosphoric acid compound extracted from the extraction line 27 has only a desired particle size, and has a high commercial value. In addition, since the phosphoric acid compound having a desired particle size or less is lighter than the phosphoric acid compound having the desired particle size, the phosphoric acid compound is positioned above the extraction line 27 until it is granulated to the desired particle size. Will be located. For this reason, a phosphoric acid compound having a desired particle size or less can be sufficiently present in the granulation vessel, and granulation can be performed until the desired particle size is obtained.
Moreover, in the dephosphorization apparatus 1 of this embodiment, the to-be-processed water supply line 22 connected with the granulation container 2 is connected with respect to the granulation container 2 from the tangent direction by planar view. For this reason, a swirling flow with the vertical direction as the central axis is formed in the granulation vessel 2. For this reason, while the to-be-processed water X in the reaction container 3 is stirred, the residence time in the granulation container 2 of the to-be-processed water X containing many phosphate ions becomes long, and in the granulation container 2 more efficiently It becomes possible to granulate the phosphoric acid compound.

  Therefore, according to the dephosphorization apparatus 1 of this embodiment, the to-be-processed water X is supplied to the granulation container 2 at a flow rate at which a phosphate compound having a desired particle size floats at the position of the extraction line 27 in the granulation container 2. Therefore, the phosphate compound having a desired particle diameter can be always extracted with stability. Moreover, since the phosphoric acid compound having a particle size smaller than the desired particle size is present in the granulation vessel 2 until the desired particle size is obtained, the phosphate compound precipitated in the reaction vessel 3 is sufficiently large. Until it becomes, it becomes possible to granulate sufficiently.

Subsequently, the air Y that has reached the recovery unit 41 in a state of being mixed with the water to be treated X is collected by the recovery unit 41 together with a part of the water to be treated X, and then the gas-liquid separator via the riser pipe 7. 8 is supplied. Here, the air Y rises with the to-be-treated water X in the riser pipe 7 without requiring a driving force such as a pump. This is because the air Y accumulates in the gas hood 44 of the recovery unit 41, thereby increasing the pressure in the gas hood 44, and as a result, the air Y rises in the riser pipe 7 together with the treated water X. Therefore, as the length of the riser pipe 7 becomes longer, the pressure loss in the riser pipe 7 becomes higher, and a higher pressure is required for the air Y to rise in the riser pipe 7. For example, when the pressure loss in the riser pipe 7 is particularly high, even if the air Y is fully accumulated in the gas hood 44, sufficient pressure cannot be obtained so that the air Y can rise. Air Y leaks out. Thus, when the air Y leaks from the gas hood 44, the rising flow rate of the supernatant liquid Z by the air Y increases as described above, and there is a possibility that the phosphate compound reaches the upper part of the reservoir 42. Therefore, it is not preferable.
For this reason, in order to suppress the leakage of the air Y from the gas hood 44 due to the pressure loss in the riser pipe 7, it is preferable to shorten the length of the riser pipe 7. The pressure loss in the riser pipe 7 is particularly high in the upper portion 71 from the recovery container 4 of the riser pipe 7, that is, in the upper portion 71 from the water surface of the treated water X. Therefore, in order to suppress the leakage of the air Y from the gas hood 44 due to the pressure loss in the riser pipe 7, it is most efficient to shorten the length of the upper portion 71 of the riser pipe 7.
That is, as in the dephosphorization apparatus 1 according to the present embodiment, the height of the upper portion 71 from the collection container 4 of the riser pipe 7, that is, the height of the upper portion 71 from the water surface of the water to be treated X It is possible to prevent the air Y from leaking out of the gas hood 44 by setting the height so that the air does not leak.
Then, the air Y that has risen along the riser pipe 7 together with a part of the water to be treated X is separated from the water to be treated X by the gas-liquid separator 8 and exhausted to the outside of the dephosphorization device 1 through the ventilation line 24. The Further, the water to be treated separated from the air Y by the gas-liquid separator 8 is supplied to the downer pipe 9.

  To-be-treated water X supplied to the downer pipe 9 is supplied with magnesium and ammonium through a magnesium / ammonium supply line 25 installed in the middle of the downer pipe 9. Thereafter, the water to be treated X is divided into the pipe 91 and the pipe 92 and supplied to the reaction vessel 3 and the granulation vessel 2. Specifically, a part of the for-treatment water X supplied through the riser pipe 7 is caused to flow into the pipe 92 by the pump 10 installed in the pipe 92, and the remaining for-treatment water X flows into the pipe 91. . And the to-be-processed water X circulated and supplied to the granulation container 2 via the pipe | tube 92 by the pump 10 is supplied in order to supplement the flow rate of the to-be-processed water X in the granulation container 2. FIG. That is, the flow rate of the water to be treated X in the granulation vessel 2 is adjusted by the water to be treated X supplied by the pump 10. By installing such a pump 10, even if the flow rate of the treated water X supplied from the outside via the treated water supply line 22 fluctuates, it is supplied to the granulation container 2 via the pipe 92. The flow rate of the treated water X to be supplied can be adjusted, whereby the flow rate of the treated water X in the entire granulation vessel 2 is extracted from the height at which the phosphate compound having a desired particle size floats. The height can be adjusted to 27. For example, when the water to be treated X supplied to the granulation container 2 through the water to be treated supply line 22 is not sufficient to obtain the above-described flow velocity, the water to be treated supplied through the pipe 92 is used. The above flow rate can be obtained by increasing X with respect to the reference flow rate by the pump 10. In addition, when the amount of the water to be treated X is too much to obtain the above-described flow velocity, the above-described flow velocity is obtained by reducing the amount of the water to be treated X supplied via the pipe 92 with respect to the reference flow rate by the pump 10. It becomes possible.

  Further, the water to be treated X supplied to the reaction vessel 3 and the granulation vessel 2 through the pipes 91 and 92 is recovered by the recovery unit 41 and separated by the gas-liquid separator 8. Still contains some phosphate compounds. For this reason, by supplying the to-be-processed water X containing such a phosphoric acid compound to the granulation container 2, granulation of the phosphoric acid compound in the granulation container 2 can be promoted, and such By supplying the water to be treated X containing the phosphate compound to the reaction vessel 3, precipitation of the phosphate compound in the reaction vessel 3 can be promoted.

Further, in the dephosphorization apparatus 1 according to the present embodiment, the magnesium / ammonium supply line 25 is installed in the middle of the downer tube 9 before branching, so that not only the reaction vessel 3 but also the granulation vessel 2 has magnesium. The to-be-processed water X containing an ion and ammonium ion can be supplied easily. Thus, by supplying the to-be-processed water X containing magnesium ion and ammonium ion to the granulation container 2, it becomes possible to further promote the granulation of a phosphoric acid compound.
As described above, the dephosphorization apparatus 1 according to this embodiment includes the separation / circulation means (the riser pipe 7, the gas-liquid separator 8, the downer pipe 9, the pipes 91 and 92, and the pump 10). It is possible to promote the precipitation of the phosphoric acid compound in 3 and promote the granulation of the phosphoric acid compound in the granulation container 2.
In addition, as described above, the pipe 91 is obliquely connected to the reaction container 3 so as to supply the water to be treated X from above to the reaction container 3, and the lower end of the stirring assist pipe 5. It is connected above 5a. For this reason, it can suppress that the to-be-processed water X supplied in the reaction container 3 via the pipe | tube 91 prevents the swirling flow S. Moreover, since the to-be-processed water X supplied into the reaction vessel 3 through the pipe 91 is stirred in the reaction vessel 3, magnesium ions and ammonium ions can be easily distributed throughout the reaction vessel 3. it can. Moreover, the pipe | tube 91 is connected with respect to the reaction container 3 from the tangent direction by planar view, as shown in FIG. For this reason, a swirling flow with the vertical direction as the central axis is formed in the reaction vessel 3. Therefore, since the to-be-processed water X in the reaction container 3 is further stirred, precipitation of a phosphoric acid compound can be promoted more. In addition, since the to-be-treated water supply line 22 for supplying the to-be-treated water X to the reaction vessel 3 from the outside is also connected to the reaction vessel 3 from the tangential direction in a plan view, the swivel around the vertical direction is the center axis. The flow can be further strengthened, and the treated water X in the reaction vessel 3 can be further stirred.

  As mentioned above, although preferred embodiment of the dephosphorization apparatus based on this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the said embodiment, in order to adjust the flow rate of the to-be-processed water X in the granulation container 2, a part of the to-be-processed water X supplied via the riser pipe | tube 7 was used. However, this invention is not limited to this, You may adjust the flow rate of the to-be-processed water X in a granulation container by supplying liquid, such as water, to the granulation container 2 from the outside.

  For example, in the above-described embodiment, the stirring assist pipe 5 is disposed in the reaction vessel 3, but the present invention is not limited to this, and a stirring device such as a propeller may be disposed in the reaction vessel 3. . However, since the phosphoric acid compound is very easy to bond with a metal, when an apparatus having a sliding part or a driving source is arranged in the reaction vessel 3, it is not preferable because frequent inspection work is required. Therefore, it is preferable to dispose the stirring means having no sliding portion and a driving source in the reaction vessel 3 like the stirring assist pipe 5 shown in the above embodiment.

  Moreover, in the said embodiment, in order to ensure an air collection area, the cross-sectional area of collection container 4 itself was made larger than the cross-sectional area of reaction container 3. However, the cross-sectional area of the recovery part 41 of the recovery container 4 may be substantially the same as the cross-sectional area of the reaction container 3 as long as the phosphate compound does not reach the supernatant Z.

It is sectional drawing which showed schematic structure of the dephosphorization apparatus 1 which concerns on one Embodiment of this invention. It is the sectional view on the AA line in FIG. It is a perspective view of collection part 41 with which dephosphorization device 1 concerning one embodiment of the present invention is provided.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Dephosphorization device 2 ... Granulation container 3 ... Reaction container 4 ... Recovery container 41 ... Recovery part 42 ... Reservoir part 5 ... Agitation assistance pipe 6 ... Diffuser 10 ... Pump (flow velocity) Adjustment means)
X …… Water to be treated Y …… Air Z …… Supernatant

Claims (7)

By blowing air in the presence of magnesium ions and ammonium ions into the water to be treated which contains phosphate ions and is supplied from the lower part of the apparatus, a phosphoric acid compound is precipitated from the water to be treated and dephosphorized. A dephosphorization device for discharging the supernatant liquid as treated water from the upper part of the device,
A granulation container that is disposed at the bottom of the apparatus and granulates the phosphoric acid compound therein, and is disposed in communication with the granulation container on the granulation container and is disposed in the treated water inside. A reaction vessel that deposits the phosphoric acid compound by blowing air; a recovery vessel that is disposed on the reaction vessel in communication with the reaction vessel and collects the air from the treated water inside; Separation / circulation means for separating the water to be treated collected together with the air and the air, and supplying the treated water after separation to the granulation vessel and the reaction vessel ,
Supplying the water to be treated to the granulation vessel at a flow rate at which a phosphoric acid compound having a desired particle size floats at a desired height in the granulation vessel ;
The separation / circulation means raises the air collected in the collection container together with a part of the water to be treated and collects the riser pipe and the water to be treated and the air collected together with the air. A gas-liquid separator, and a downer pipe for supplying the treated water after separation to the granulation container and the reaction container, wherein the height of the riser pipe above the treated water surface is from the recovery container. The dephosphorization device is set so that the air does not leak out . 2. The dephosphorization according to claim 1, wherein a flow rate at which a phosphoric acid compound having a desired particle diameter floats at a desired height in the granulation container is achieved by defining a container diameter of the granulation container. apparatus. The dephosphorization apparatus according to claim 1 or 2, wherein a horizontal cross section of the granulation vessel is circular, and the water to be treated is supplied into the granulation vessel from a tangential direction of the granulation vessel. . The dephosphorization apparatus according to any one of claims 1 to 3, further comprising a flow rate adjusting means for adjusting a flow rate of the water to be treated in the granulation vessel. The dephosphorization apparatus according to claim 4, wherein the flow rate adjusting means is a pump that circulates a part of the water to be treated in the reaction vessel and supplies the water to the granulation vessel. The recovery container includes a recovery unit that recovers the air from the treated water, and a storage unit that is disposed on the recovery unit and stores the treated water from which the air has been recovered by the recovery unit. The dephosphorization device according to claim 1, wherein at least the cross-sectional area of the recovery portion of the recovery container is set wider than the cross-sectional area of the reaction container . The dephosphorization device according to any one of claims 1 to 6, wherein a cross section of the collection container is set to a rectangular shape .

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