JP5875142B2 - Calcium scale prevention device and prevention method - Google Patents

Description

  The present invention relates to a calcium scale prevention device and prevention method, and more particularly to an apparatus and method for preventing the generation of scale due to calcium in a final disposal site, a cement manufacturing process, and the like.

  Waste disposal sites and other final disposal sites are facilities for disposing of wastes that are difficult to recycle. However, in view of the danger of exhaustion, effective use of wastes that have been treated at the final disposal site so far Is promoted. For example, incineration ash generated when municipal waste is incinerated has recently been recycled as a cement raw material. Of municipal incineration ash, fly ash that is carried with gas and collected by the dust collector contains 10 to 20% of chlorine, so water-soluble chlorine contained in fly ash using water washing and desalination equipment After removing the compound with water, it is used as a cement raw material (see, for example, Patent Document 1).

  On the other hand, a chlorine bypass facility that removes chlorine that causes problems such as blockage of a preheater is used in a cement manufacturing facility. In recent years, recycling of waste containing incinerated ash as cement raw material or fuel has been promoted, and as the amount of waste processed increases, the amount of volatile components such as chlorine brought into the cement kiln also increases. The amount of dust generated is also increasing. Therefore, all the chlorine bypass dust cannot be used in the cement pulverization process, and the chlorine bypass dust is also washed with water (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 11-100343 JP 2001-129513 A

However, at the final disposal site, calcium ions (Ca ²⁺ ) contained in the leachate and SO ₄ ^2- produce calcium sulfate (CaSO ₄ ), which is used as a scale in leachate treatment equipment and the wastewater treatment process in the subsequent stage. There was a problem that it adhered to the apparatus and the stable operation was hindered. In addition, the incineration ash and chlorine bypass dust washing filtrate in the cement manufacturing process have the same problems as the leachate in the final disposal site.

  Therefore, for example, as shown in FIG. 6, the leachate W1 from the final disposal site 50 is stored in the sedimentation / regulation pond 51, and the calcium that causes scale generation from the leachate W2 discharged from the sedimentation / regulation pond 51. In addition, in order to remove harmful heavy metals, chemicals are added in the chemical reaction tank 52, these are precipitated and removed by the filtration device 53, and then discharged after disinfection through COD treatment and removal of suspended solids (SS). .

  However, in order to remove the calcium, it is necessary to add a large amount of sodium carbonate or potassium carbonate, which increases the cost of the drug and raises the operating cost.

  Therefore, the present invention has been made in view of the problems in the above-described conventional technology, and minimizes adverse effects on operation due to scale adhesion at a final disposal site or the like, and reduces operation costs including drug costs. The purpose is to suppress.

To achieve the above object, the present invention provides a a calcium scale preventing apparatus, Ca ²⁺ and, SO ₄ ^2-or / and C _² O ₄ ^2- and solution filtration unit for filtering the containing, the filtration has been the solution with discharge from the machine and reclaimed water are supplied alternately, first a solution Ca ²⁺ concentration is low SO ₄ ^2-or / and C _² O ₄ ^2- concentration is high, high Ca ²⁺ concentration And an amphoteric ion exchange resin that alternately discharges a second solution having a low concentration of SO ₄ ²⁻ and / or C ₂ O ₄ ²⁻ with the passage of time.

Then, according to the present invention, and by using an amphoteric ion exchange resin Ca ²⁺ concentration first SO ₄ ^2-or / and C _² O ₄ ^2- concentration is high low solution, high Ca ²⁺ concentration Since it is separated into the second solution having a low concentration of SO ₄ ²⁻ and / or C ₂ O ₄ ^{2−, the} scale is made of CaSO ₄ or the like without adding sodium carbonate or the like to remove calcium ions as in the prior art. Can be minimized, and the operating cost can be greatly reduced.

In addition, since a solution containing Ca ²⁺ and SO ₄ ²⁻ and / or C ₂ O ₄ ²⁻ is filtered with a filter and then passed through the amphoteric ion exchange resin, the amphoteric ion exchange resin itself has a calcium scale. It is possible to prevent the resin from adhering and solidifying, and the stable operation of the amphoteric ion exchange resin can be maintained.

In the above calcium scale inhibition device, the said Ca ²⁺ amphoteric ion-exchange resin, the supply pipe for supplying a solution containing the SO ₄ ^2-or / and C _² O ₄ ^2-, comprising the filtration device it can, thereby, the raw water can correspond directly to the scale adhesion (and Ca ^2+, SO ₄ ^2- or / and C _² O ₄ ^2- and a solution containing a).

In the calcium scale inhibition device, the said Ca ²⁺ in the amphoteric ion-exchange resin, a supply pipe for supplying a solution containing SO ₄ ^2-or / and the C _² O ₄ ^2-, wherein the amphoteric ion-exchange resin downstream plumbing confluence of the regeneration water supply pipe for supplying regeneration water can comprise the filtration unit. As a result, the filter can be washed with reclaimed water, and the filter can be operated for a long period of time.

  In the above calcium scale prevention device, the filter may be one in which the maximum diameter of particles to be removed is set to 10 μm or less. When a filter type is adopted for the filter, the diameter of the hole through which the particles pass can be 10 μm or less. When a sand filter is employed, it is possible to adjust the speed of the solution passing through the filter medium and the filter so that the maximum diameter of particles to be removed is 10 μm or less.

The present invention also relates to a calcium scale prevention method, wherein a solution containing Ca ²⁺ and SO ₄ ²⁻ and / or C ₂ O ₄ ²⁻ is filtered, and the filtered solution and reclaimed water are combined. amphoteric ion-exchange resin is passed through alternately, Ca ²⁺ concentration is low SO ₄ ^2-or / and C _² O ₄ ^2- concentration and high first solution, Ca ²⁺ concentration is high SO ₄ ^2-or / And the second solution having a low C ₂ O ₄ ²⁻ concentration is alternately discharged over time. According to the present invention, as in the case of the above-described invention, the generation of scale due to CaSO ₄ or the like can be minimized, and the operating cost can be greatly reduced, and the calcium scale adheres to the amphoteric ion exchange resin itself. Thus, the resin can be prevented from solidifying, and the stable operation of the amphoteric ion exchange resin can be maintained.

In the calcium scale prevention method, a filter for performing the filtration is installed in a supply pipe for supplying a solution containing the Ca ²⁺ and SO ₄ ²⁻ and / or C ₂ O ₄ ²⁻ to the amphoteric ion exchange resin. The speed of the solution passing through the filter can be controlled to 200 m / day or less. As a result, it is possible to directly cope with the scale adhesion of raw water, and by controlling the speed of the solution passing through the filter to 200 m / day or less, that is, by installing a filter with a large capacity, Long-term operation of the machine can be ensured.

In the calcium scale inhibition method, the recycled water the said Ca ²⁺ amphoteric ion-exchange resin, a supply pipe for supplying a solution containing SO ₄ ^2-or / and C _² O ₄ ^2-, and the amphoteric ion-exchange resin The filter which performs the said filtration is installed in the piping of the downstream of the confluence | merging point with the reclaimed water supply piping which supplies water, and the speed | rate of this solution which passes this filter can be controlled to 200 m / day or more. As a result, the filter is washed with reclaimed water to ensure a long-term stable operation of the filter, and the speed of the solution passing through the filter is controlled to 200 m / day or more, that is, the filter has a small capacity. By installing, it can prevent that raw | natural water and reclaimed water mix and separation performance (filtration performance) falls.

  As described above, according to the present invention, it is possible to minimize the adverse effect on the operation due to the adhesion of the scale at the final disposal site, etc., and to keep the operation cost including the drug cost low.

It is a flowchart which shows the leachate treatment system of the final disposal site using 1st Embodiment of the calcium scale prevention apparatus concerning this invention. It is the schematic for demonstrating operation | movement of the amphoteric ion exchange resin used for the leachate treatment system of the final disposal site shown in FIG. It is a graph which shows the operation example of amphoteric ion exchange resin shown in FIG. It is a flowchart which shows the Example of the leachate treatment system of the final disposal site shown in FIG. It is a flowchart which shows the leachate treatment system of the final disposal site using 2nd Embodiment of the calcium scale prevention apparatus concerning this invention. It is a flowchart which shows an example of the leachate treatment system of the conventional final disposal site.

  Next, modes for carrying out the present invention will be described with reference to the drawings. In the following description, a case where the present invention is used for preventing calcium scale in a final disposal site will be described as an example.

FIG. 1 shows a leachate treatment system (hereinafter abbreviated as “treatment system”) at a final disposal site using the first embodiment of the calcium scale prevention apparatus according to the present invention. The adjustment tank 3 for storing the leachate W1 from the disposal site 2, the filter 4 for filtering the leachate W2 from the adjustment tank 3, and the solution L1 discharged from the filter 4 into a solution having a high calcium ion concentration ( The amphoteric ion exchange resin 5 which is separated into a solution L3 having a low calcium ion concentration and a high SO ₄ ²⁻ concentration (hereinafter referred to as “SO ₄ containing water”) L4, and an amphoteric ion exchange resin. a recycled water tank 6 for storing the regeneration water L2 supplied to 5, calcium-containing water tank 7 for storing the calcium-containing water L3 and SO ₄ containing water L4 discharged from amphoteric ion-exchange resin 5 each Comprising a SO ₄ containing water tank 8, a heavy metal removing device 9, and a COD processor 10.

  The adjustment tank 3 collects the leachate W1 such as rainwater that has permeated through the waste layer of the final disposal site 2, and is prepared to suppress the change in the water quality and the amount of the leachate W1 and to make it uniform. A sand settling tank for sedimentation and separation of earth and sand is provided.

  In order to filter the leachate W2 from the adjustment tank 3, the filter 4 is arrange | positioned at the piping which supplies the leachate W2 to the amphoteric ion exchange resin 5, and filters the leachate W2 directly. When the sand filter is used, the filter 4 has a maximum diameter of sand or other filter medium of 2.0 mm or less and a minimum diameter of 0.15 mm or more so that the maximum diameter of particles to be removed is 10 μm or less. The speed of the leachate W2 passing through the filter 4 can be a relatively large filter of 100 to 200 m / day.

  The amphoteric ion exchange resin 5 is provided to remove calcium contained in the solution L1 discharged from the filter 4. The amphoteric ion exchange resin has a function of allowing ion exchange with both cation and anion by making the base material cross-linked polystyrene or the like and having a quaternary ammonium group and a carboxylic acid group in the same functional group chain. Resin. For example, amphoteric ion exchange resin, Diaion (registered trademark), AMP03 manufactured by Mitsubishi Chemical Corporation can be used. The amphoteric ion exchange resin 5 can separate the electrolyte and the non-electrolyte in the aqueous solution, and can also separate the electrolytes from each other.

The heavy metal removing device 9 is provided for removing heavy metals such as lead contained in the SO ₄ -containing water L4, and a commonly used device such as a chemical reaction tank or a filter press can be used.

The COD processing apparatus 10 is provided for reducing the COD of the SO ₄ -containing water L4 from which heavy metals have been removed by the heavy metal removing apparatus 9, and a general septic tank or the like can be used.

  Next, the operation of the processing system 1 having the above configuration will be described with reference to FIG.

  The leachate W1 from the final disposal site 2 is collected in the adjustment tank 3 to suppress changes in water quality and water volume, and then the leachate W2 from the adjustment tank 3 is filtered by the filter 4. This prevents calcium scale from adhering to the amphoteric ion exchange resin 5 itself and causing the resin to solidify.

Next, the filtered solution L1 is supplied to the amphoteric ion exchange resin 5, and the solution L1 is separated into calcium-containing water L3 and SO ₄ -containing water L4. As shown in FIG. 2, this amphoteric ion exchange resin 5 performs batch processing continuously, and is previously filled with water (FIG. 2A), and then the amphoteric ion exchange resin from the filter 4. The solution L1 is introduced into 5, and then reclaimed water (engineering water) L2 for regenerating the amphoteric ion exchange resin 5 is introduced (FIG. 2 (b)). Then, as shown in FIG. 2 (c), it is first discharged SO ₄ containing water L4, then, calcium-containing water L3 is discharged in this order over time. The SO ₄ -containing water L4 and the calcium-containing water L3 discharged from the amphoteric ion exchange resin 5 are temporarily stored in the SO ₄ -containing water tank 8 and the calcium-containing water tank 7, respectively.

Next, the calcium-containing water L3 stored in the calcium-containing water tank 7 is discharged. On the other hand, the SO ₄ -containing water L ₄ stored in the SO ₄ -containing water tank 8 removes heavy metals using the heavy metal removing device 9, further reduces COD by the COD processing device 10, and then discharges it.

As described above, according to the present embodiment, the leachate W2 is separated into the calcium-containing water L3 and the SO ₄ -containing water L4 through the filter 4 and the amphoteric ion exchange resin 5, and then each is separated separately. Since the treatment is performed, the generation of scale due to CaSO ₄ can be minimized without adding sodium carbonate or the like for removing calcium as in the prior art, and the operating cost can be greatly reduced.

  In addition, since the leachate W2 is filtered in advance by the filter 4 to prevent the calcium scale from adhering to the amphoteric ion exchange resin 5 itself and preventing the resin from solidifying, the amphoteric ion exchange resin 5 can be operated stably. Can be maintained. Here, since the leachate W2 is directly filtered by the filter 4, it is possible to directly cope with the scale adhesion of the leachate W2, and the speed of the leachate W2 passing through the filter 4 is 200 m / day or less. The long-term operation of the filter 4 can be ensured by controlling the filter 4, that is, by installing a filter having a large capacity.

Next, an embodiment of the calcium scale prevention device and the prevention method used in the processing system 1 will be described. As the filter 4, a cartridge filter having a diameter of 10 μm is used, the speed of the leachate W2 passing through the filter 4 is controlled at 59 m / day, and the amphoteric ion exchange resin 5 is used as the amphoteric ion manufactured by the above-mentioned Mitsubishi Chemical Corporation. Using the exchange resin, Diaion AMP03, as raw water, the leachate W2 of the final disposal site 2 having the chemical components shown in Table 1 is passed through the filter 4 and the amphoteric ion exchange resin 5, and the reclaimed water L2 of the leachate W2 is recycled. Twice the amount of fresh water was passed. Table 2 and FIGS. 3 and 4 show the relationship between the flow rate and the concentration of each component contained in the treatment liquid that has passed through the amphoteric ion exchange resin 5 and the water balance in the treatment system 1 at that time. In FIG. 4, the numbers in the ellipses indicate the weight ratio of each water. Incidentally, Table 1, Table 2 and Figure 3, the measured electric conductivity Cl ^- shows in terms of concentration.

In Table 2 and FIG. 3, the water flow rate / raw water amount 0.14 to 1.43 is SO ₄ -containing water L4, and the water flow rate / raw water amount 1.43 and later is calcium-containing water L3. As apparent from the table and graph, in the SO ₄ -containing water L4, in addition to SO ₄ ²⁻ , Cl ⁻ and Na ⁺ can be recovered, and Pb ²⁺ , COD and NH ₄ ⁺ are also SO _{4. Since} it can isolate | separate toward ₄ containing water L4, about these calcium containing water L3, these removal facilities become unnecessary and can suppress an installation cost and an operating cost low.

In addition, as shown in FIG. 4, when the solution L1 having a weight of 0.67 and the regenerated water L2 having a weight of 1.33 are supplied to the amphoteric ion exchange resin 5, the water balance at this time is as follows. 1 SO ₄ -containing water L4 is generated and treated separately and discharged.

  Next, a processing system using the second embodiment of the calcium scale preventing apparatus according to the present invention will be described with reference to FIG.

The treatment system 11 includes an adjustment tank 3 that stores the leachate W1 from the final disposal site 2, a filter 14 that filters the leachate W2 from the adjustment tank 3, and a solution L5 discharged from the filter 14. Amphoteric ion exchange resin that separates into a solution with high calcium ion concentration (hereinafter referred to as “calcium-containing water”) L6 and a solution with low calcium ion concentration and high SO ₄ ²⁻ concentration (hereinafter referred to as “SO ₄ -containing water”) L7. 5, a reclaimed water tank 6 for storing reclaimed water L2 supplied to the filter 14, a calcium-containing water tank 7 for storing calcium-containing water L6 and SO ₄ -containing water L7 discharged from the amphoteric ion exchange resin 5, and SO _4. A contained water tank 8, a heavy metal removing device 9, and a COD processing device 10 are provided. The amphoteric ion exchange resin 5 to the COD processing apparatus 10 has the same configuration as the processing system 1 in the first embodiment.

  In order to filter the leachate W2 from the adjustment tank 3, the filter 14 is disposed in a pipe downstream of the junction M between the supply pipe for the leachate W2 and the supply pipe for the reclaimed water L2, and filters the leachate W2. At the same time, the filter 14 is washed with the reclaimed water L2. When this filter 14 employs a sand filter, the maximum diameter of the filter medium such as sand is 2.0 mm or less and the minimum diameter is 0.3 mm or more so that the maximum diameter of particles to be removed is 10 μm or less. A relatively small filter having a speed of the leachate W2 and the reclaimed water L2 passing through the filter 14 of 200 to 500 m / day can be employed.

  Next, the operation of the processing system 11 having the above configuration will be described with reference to FIG.

  After the leachate W1 from the final disposal site 2 is collected in the adjustment tank 3 to suppress changes in water quality and water volume, the leachate W2 from the adjustment tank 3 and the reclaimed water L2 from the reclaimed water tank 6 are filtered by the filter 14 to be amphoteric. It prevents the calcium scale from adhering to the ion exchange resin 5 itself and solidifying the resin.

Next, the filtered solution L5 is supplied to the amphoteric ion exchange resin 5, and the solution L5 is separated into calcium-containing water L6 and SO ₄ -containing water L7. The SO ₄ -containing water L7 and the calcium-containing water L6 discharged from the amphoteric ion exchange resin 5 are temporarily stored in the SO ₄ -containing water tank 8 and the calcium-containing water tank 7, respectively.

Next, the calcium-containing water L6 stored in the calcium-containing water tank 7 is discharged. On the other hand, the SO ₄ -containing water L 7 stored in the SO ₄ -containing water tank 8 removes heavy metals using the heavy metal removing device 9, further reduces COD by the COD treatment device 10, and then discharges it.

As described above, according to the present embodiment, the leachate W2 is separated into the calcium-containing water L6 and the SO ₄ -containing water L7 through the filter 14 and the amphoteric ion exchange resin 5, and then each is separately separated. Since the treatment is performed, the generation of scale due to CaSO ₄ can be minimized without adding sodium carbonate or the like for removing calcium as in the prior art, and the operating cost can be greatly reduced.

  In addition, since the leachate W2 is filtered together with the regenerated water L2 in advance with the filter 14 to prevent the calcium scale from adhering to the amphoteric ion exchange resin 5 itself to prevent the resin from solidifying, the stability of the amphoteric ion exchange resin 5 is stabilized. Operation can be maintained. Here, by supplying the reclaimed water L2 to the filter 14 and washing the filter 14, the long-term stable operation of the filter 14 is ensured, and the speed of the leachate W2 and the reclaimed water L2 passing through the filter 14 is set to 200 m. / By controlling more than a day, that is, by installing a filter having a small capacity, it is possible to prevent the leachate W2 and the reclaimed water L2 from mixing and separating performance (filtration performance) from being lowered. .

In the above embodiment, the case where the calcium scale prevention device and the prevention method according to the present invention are applied to the leachate treatment system of the final disposal site is exemplified, but in addition to the leachate treatment system, incineration ash, Filtration obtained by washing chlorine bypass dust obtained in the cement manufacturing process, drainage of salt recovery equipment that recovers salt from seawater, etc., a solution containing calcium ions, SO ₄ ^2- , oxalate ions, etc. The present invention can be applied to any solution that may cause a scale due to calcium ions.

1 Final leachate treatment system 2 Final disposal site 3 Conditioning tank 4 Filter 5 Amphoteric ion exchange resin 6 Recycled water tank 7 Calcium-containing water tank 8 SO ₄ -containing water tank 9 Heavy metal removal device 10 COD treatment device 11 Final disposal site Leachate treatment system 14

Claims (7)

And Ca ^2+, and SO ₄ ^2-or / and C _² O ₄ ^2- and filtration machine for filtering a solution comprising,
And the solution drained from the filtration unit and reclaimed water are supplied alternately, Ca ²⁺ first and solution concentration SO ₄ ^2-or / and C _² O ₄ ^2- concentration low is high, Ca ²⁺ concentration And an amphoteric ion exchange resin that alternately discharges a second solution having a high SO ₄ ²⁻ and / or a low concentration of C ₂ O ₄ ²⁻ as time elapses. It said Ca ²⁺ in the amphoteric ion-exchange resin, the supply pipe for supplying a solution containing SO ₄ ^2-or / and the C _² O ₄ ^2-, to claim 1, characterized in that it comprises the filtration machine The calcium scale prevention apparatus of description. The Ca ²⁺ and, SO ₄ ^2-or / and C _² O ₄ ^2- and reclaimed water supply pipe for supplying a supply pipe for supplying a solution, said regeneration water amphoteric ion-exchange resin containing the amphoteric ion-exchange resin The calcium scale prevention device according to claim 1 , wherein the filter is provided in a pipe on the downstream side of the junction with the calcium scale.   The calcium scale prevention device according to claim 1, 2 or 3, wherein the maximum diameter of particles removed by the filter is 10 µm or less. And Ca ^2+, SO ₄ ^2- or / and C _² O ₄ ^2- and a solution containing filtered,
The The filtered and the solution after the regeneration water is passed alternately amphoteric ion-exchange resin, and the SO ₄ ^2-or / and C _² O ₄ ^2- concentration low Ca ²⁺ concentrations higher first solution, Ca ^A method for preventing calcium scale, characterized in that a second solution having a high ²⁺ concentration and a low SO ₄ ²⁻ and / or C ₂ O ₄ ²⁻ concentration is alternately discharged over time. A filter for performing the filtration is installed in a supply pipe for supplying a solution containing the Ca ²⁺ and SO ₄ ^2- or / and C ₂ O ₄ ^2- to the amphoteric ion exchange resin. 6. The calcium scale prevention method according to claim 5, wherein the speed of the solution passing through is controlled to 200 m / day or less. The Ca ²⁺ and, SO ₄ ^2-or / and C _² O ₄ ^2- and reclaimed water supply pipe for supplying a supply pipe for supplying a solution, said regeneration water amphoteric ion-exchange resin containing the amphoteric ion-exchange resin The filter which performs the said filtration is installed in piping downstream from the confluence | merging point, and the speed | velocity | rate of this solution which passes this filter is controlled to 200 m / day or more. Calcium scale prevention method.

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