JP3369726B2 - Filtration and desalination equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtration and desalination apparatus used in power plants and the like, and more particularly to a filtration and desalination apparatus corresponding to the charge of a powdered ion exchange resin to be applied. Related to salt equipment. 2. Description of the Related Art For purification of reactor water and spent fuel storage pool water of a nuclear power plant, microfiltration and ion exchange are simultaneously performed, and pressure precoat type microfiltration desalination using powder ion exchange resin as a filter medium. The device is being used. [0003] The filter medium in this filter desalination apparatus is a mixture of powdered anion exchange resin and cation exchange resin in water, and is precoated with pressure on the outer peripheral surface of a number of filter elements installed in the filter desalter. Used. When an anion resin and a cation resin are mixed in water, the binding force changes depending on the ratio of the anion resin and the cation resin. However, since the agglomeration is usually highly agglomerated, it is uniformly applied to the filtration element as it is. Cannot be pre-coated. [0005] For this purpose, a polyelectrolyte solution, which is a coagulation inhibitor, has been conventionally added to a mixed solution slurry of an anionic resin and a cationic resin so that the outer peripheral surface of the filtration element can be precoated with an appropriate porosity. The state of aggregation is adjusted. [0006] Generally, a filtration and desalination apparatus is composed of a filtration and desalination tower, a backwash precoat facility, and a control facility for them, and a filtration and desalination apparatus used up to a specified design value uses ion exchange used by backwash operation. The resin is discarded and a new ion exchange resin is pre-coated and used. As shown in the flow chart of FIG. 3, during normal operation of the filter and desalination apparatus, water to be filtered and desalinated is supplied to the system 1.
It is led into the filtration and desalination tower 4 via the valve 2 and the pipe 3. The system water filtered and desalinated in the filtration and desalination tower 4 is returned to a predetermined system 7 through a pipe 5 and a valve 6. In the filtration and desalination tower 4, the ion exchange resin layer 9 made of the powdered ion exchange resin precoated on the surface of the filtration element 8 consumes the ion exchange capacity due to the filtration and desalination treatment of the filtration and desalination tower 4. . When this reaches the so-called ion break state, air or water for backwashing flows from the pipe 5 in a direction opposite to the above-mentioned normal water flow direction, and the ion-exchange resin which has been pre-coated so far is used. The layer 9 is peeled off from the filtration element 8, passed through the pipe 3, the valve 10, and the pipe 11, and back-transferred to the waste treatment system 12. Next, the filter element 8 in the filter desalination tower 4
When the ion-exchange resin layer 9 is formed by pre-coating a new powder ion-exchange resin, first, a pre-coat tank
13 is charged with powdered ion exchange resin 14 and water is added. Further, a predetermined amount of a polyelectrolyte solution 15 as an aggregation inhibitor per unit weight of the ion exchange resin is manually charged and stirred by a stirrer 16 to form a uniform slurry. Sampling is performed, and the mixture is left for a certain period of time to measure the specific volume of the mixed solution slurry in which the powder ion exchange resin 14 has settled. After confirming that these are within the reference value range, the precoat pump 17 is operated, and the valve 18 and the piping 3
Through the filter element 8 in the filter and desalination tower 4, and the water passed through the pipe 5 and the valve 19 is returned to the precoat tank 13 again. By this operation, an ion exchange resin layer 9 made of the powder ion exchange resin 14 is formed on the surface of the filtration element 8 in the filtration and desalination tower 4. If the specific volume at this time is equal to or larger than a specified value by the sampling, the polyelectrolyte solution
Add 15 and stir according to the same procedure as above, mix and measure again by sampling again. When the specific volume is equal to or less than the specified value, the powder ion exchange resin slurry in the precoat tank 13 is discarded, and the slurry is adjusted by a new powder ion exchange resin 14 according to the above procedure. In the case where the ion exchange resin layer 9 is formed on the filtration element 8 in the filtration and desalination tower 4,
The predetermined amount of the polyelectrolyte solution 15 as the coagulation inhibitor to be charged into the precoat tank 13 is set based on the amount per unit weight of the powdered ion exchange resin 14 obtained by experiments and the like. However, the powder ion exchange resin 14
The charge may be different in the manufacturing process and the like, and this difference in charge may result in a different agglomeration rate with respect to the width of the specific volume reference value, for example, even when a predetermined amount of the polyelectrolyte solution 15 is charged. Therefore, there was a problem that the filtration and desalination performance varied. As shown in the characteristic diagram of FIG. 2A, when the polyelectrolyte solution 15 charged for the purpose of coagulation adjustment exceeds a certain amount even when the polyelectrolyte solution Since the change tends to be small, the polyelectrolyte solution 15 is likely to be excessively charged. At this time, the excess polyelectrolyte solution 15 exceeding the agglomeration rate of the powdered ion exchange resin 14 is discharged out of the filtration and desalination apparatus, so that the TOC
(Total organic carbon content) and other adverse effects on water quality are caused.
From these facts, it is desirable that an appropriate amount of the polyelectrolyte solution 15 is added to the specific agglomeration rate due to the charge of each powder ion exchange resin 14. It is an object of the present invention to provide a filter desalting apparatus for automatically adjusting a powder ion exchange resin slurry having an optimum coagulation rate by providing a conductivity measuring device and a coagulant charging device in a precoat tank. To provide. [0020] [0021] [0022] [0023] Means for Solving the Problems] filtration demineralizer according to the invention of <br/> claim 1, wherein for achieving the above object, the filtration demineralizer In a filtration and desalination apparatus equipped with a precoat tank for preparing a slurry by adding a flocculation inhibitor to the powder ion exchange resin and forming the powder ion exchange resin as a filter medium,
In the pre-coat tank, a slurry made of powder ion exchange resin is used.
When the electric conductivity measuring means and the coagulation inhibitor input means are installed,
In both cases, the saturated state of the slurry by the powder ion exchange resin is determined from the correlation between the conductivity from the conductivity measurement unit and the specific volume and conductivity of the polyelectrolyte that is the aggregation inhibitor for the powder ion exchange resin set in advance. A control device that instructs the coagulation inhibitor input means to input the coagulation inhibitor so as to set the coagulation inhibitor into an appropriate coagulation state in the case of an inappropriate coagulation state as a filter medium
Is provided . [0024] [0025] [0026] [0027] [action] first aspect of the present invention, the conductivity of the slurry by powder ion exchange resin precoat tank that conductivity measuring means has measured and preset powder From the correlation between the specific volume of the coagulation inhibitor and the conductivity for the ion exchange resin,
To determine the saturation of the slurry by powder ion exchange resin in the case of improper aggregated state as filter media and issued a closing command of the aggregation inhibitor such as a suitable aggregating state aggregation inhibitor dosing means, powders ion Slurry with exchange resin
Adjust to the collection state . An embodiment of the present invention will be described with reference to the drawings. The same components as those of the above-described conventional technology are denoted by the same reference numerals, and detailed description thereof will be omitted. As shown in the block diagram of FIG. 1, the water to be filtered and desalinated is introduced from a system 1 into a filtration and desalination tower 4 via a valve 2 and a pipe 3, The filtered and desalinated system water is returned to a predetermined system 7 through a pipe 5 and a valve 6. The filtration element 8 in the filtration desalination tower 4
Is precoated with an ion-exchange resin layer 9 of powdered ion-exchange resin 14. When the ion exchange capacity is consumed by the filtration and desalination treatment of the system water in the filtration and desalination tower 4, and when a so-called ion break state is reached, the pipe 5 is moved in the opposite direction to the normal flow direction described above. A backwash operation in which air or water for backwash flows from the filter element, thereby peeling off the ion-exchange resin layer 9 previously coated on the surface of the filter element 8 and piping the powder ion-exchange resin 14 into a pipe. 3 and transferred to a waste treatment system 12 (not shown). The precoat tank 13 for adjusting the slurry of the powder ion exchange resin 14 for forming the ion exchange resin layer 9 by precoating the filter element 8 in the filter desalination tower 4 of the filter desalination apparatus is provided by A stirrer 16 is provided for charging the ion-exchange resin 14 and water, charging the polyelectrolyte solution 15 as an agglutination inhibitor, and stirring these so as to form a uniform slurry. The precoat tank 13 is provided with a precoat pump 17 for sending the slurry of the powdered ion exchange resin 14 to the filter desalination tower 4 between the pipe 3 and the precoat tank 13. Valve 19 for returning excess water is pipe 5
And between them. Further, the precoat tank 13 is provided with a coagulation inhibitor charging device 20 as a coagulation inhibitor charging device and a supernatant water conductivity measuring device 21 as a slurry conductivity measuring device. Connect with 23. The coagulation inhibitor input device 20 and the conductivity measuring device 21 of the supernatant water are provided with a conductivity signal from the conductivity measuring device 21 and a polyelectrolyte solution feeding amount obtained in advance through experiments, a supernatant conductivity and a ratio. By the correlation of the volume, the saturation state of the powder ion exchange resin slurry is determined by measuring the supernatant conductivity, and if the conductivity is equal to or less than the predetermined conductivity, the polyelectrolyte solution 15 is automatically fed to the coagulation inhibitor feeding device 20. It is configured to be connected to a control device 24 that issues a command. Next, the operation of the above configuration will be described. Initially, the powder ion-exchange resin 14 manually charged into the precoat tank 13 is added with an appropriate amount of a polyelectrolyte solution 15 as an aggregation inhibitor by manual charging, and stirred by a stirrer 16 to form a slurry. The slurry of the powder ion exchange resin 14 is
The supernatant water is led to a conductivity measuring device 21 via a pipe 23. The controller 24 determines whether the supernatant water conductivity of the slurry of the powdered ion exchange resin 14 measured by the conductivity measuring device 21 is a predetermined value. As shown in the characteristic diagrams of FIGS. 2 (a) and 2 (b), this discrimination is based on the correlation between the input amount of the polyelectrolyte obtained in the experiment, the supernatant water conductivity and the specific volume, and the supernatant water conductivity. The saturated state (agglomerated state) of the ion exchange resin 14 is determined. When the conductivity of the supernatant water of the slurry of the powdered ion exchange resin 14 is equal to or less than a predetermined value, the control device 24 issues an operation command signal to the coagulation inhibitor input device 20 to supply a predetermined amount of the polyelectrolyte solution 15 to the piping. Automatically put into the precoat tank 13 from 22. The stirrer 16 stirs the slurry, and the conductivity measuring device 21 measures the supernatant water conductivity. Control device 24
Is repeated until the supernatant water conductivity reaches a predetermined value. The slurry of the powdered ion exchange resin 14 drawn into the conductivity measuring device 21 of the supernatant water from the precoat tank 13 via the pipe 23 is returned to the precoat tank 13 again from the pipe 22 after measuring the conductivity of the supernatant water. . When a predetermined amount of the polyelectrolyte solution 15 is automatically charged from the pipe 22 into the precoat tank 13 and is stirred by the stirrer 16 and the slurry of the powder ion exchange resin 14 is in a state suitable for the precoat, the controller 24 Stops charging the polyelectrolyte solution 15 into the coagulation inhibitor charging device 20. As a result, the slurry of the powdered ion exchange resin 14 in the precoat tank 13 is supplied to the powdered ion exchange resin 14 at which the agglomeration rate is optimized by introducing the optimal amount of the polyelectrolyte solution 15 for each powdered ion exchange resin 14. The slurry is adjusted automatically. Further, since the polyelectrolyte solution 15 is not excessively charged, the deterioration of the water quality of the plant waste liquid due to the discharge of the surplus polyelectrolyte solution 15 out of the filtration and desalination apparatus is mitigated. Thereafter, by operating the precoat pump 17, a new ion exchange resin layer 9 is formed on the filter element 8 in the filter and desalination tower 4 by the precoat having excellent filtration and desalination performance by the powder ion exchange resin 14. Can be formed. As described above, according to the present invention, an excessive amount of the coagulation inhibitor is prevented by automatically adding an appropriate amount of the coagulation inhibitor to the coagulation rate of each powder ion exchange resin. In addition, there is an effect that the performance of the filtration and desalination apparatus is stabilized, the waste liquid is reduced, and the burden on the operator is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a filtration and desalination apparatus according to the present invention. FIG. 2 is a characteristic diagram showing a correlation between polyelectrolyte input and electric conductivity, wherein (a) shows polyelectrolyte mass and specific volume, and (b) shows polyelectrolyte mass and electric conductivity of supernatant water. FIG. 3 is an explanatory diagram of a flow of a conventional filtration and desalination apparatus. [Explanation of symbols] 1,7 ... system, 2,6,10,18,19 ... valve, 3,5,11,
22, 23… Piping, 4… Filter desalination tower, 8… Filter element,
9: Powder ion exchange resin layer, 12: Waste treatment system, 13: Precoat tank, 14: Powder ion exchange resin, 15: Polyelectrolyte solution, 16: Stirrer, 17: Precoat pump, 20: Aggregation inhibitor feeding device , 21… Conductivity measuring device for supernatant water, 24…
Control device.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-209643 (JP, A) JP-A-55-51480 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21F 9/06 C02F 1/42

Claims (1)

(57) [Claims 1] A pre-coat tank for preparing a slurry by forming a powder ion-exchange resin as a filter medium in a filtration desalination tower and adding a coagulation inhibitor to the powder ion-exchange resin. In the filtration desalination apparatus, the powder is stored in the precoat tank.
Slurry conductivity measuring means and aggregation suppression by ion exchange resin
A slurry feeding means is provided based on the correlation between the conductivity from the conductivity measuring means and the specific volume and conductivity of the polyelectrolyte, which is a coagulation inhibitor, for the powder ion exchange resin. In the case of an unsuitable aggregation state as a filter medium by judging the saturation state of the filter medium, a control device for instructing the injection of the aggregation inhibitor to provide an appropriate aggregation state to the aggregation inhibitor input means is provided. to Carlo <br/> over demineralizer.