JPS6133625B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for regenerating a single-bed ion exchange tower filled with a single strong electrolyte ion exchange resin, and includes providing a collection and distribution pipe for a regenerated chemical solution in the ion exchange resin layer. The ion exchange resin layer below the liquid collection and distribution pipe is regenerated by the downward flow of the regenerated chemical solution, the regenerated waste liquid is recovered, and the regenerated waste liquid is passed downwardly from the upper part of the ion exchange column to the ion exchange column. By regenerating the ion exchange resin layer above the liquid collection and distribution pipe, the purpose is to reduce the amount of regenerated chemical solution used, increase regeneration efficiency, and improve the purity of treated water. Traditionally, the ion exchange treatment method was to use downward flow water.
The most commonly used methods are the downflow regeneration method (hereinafter referred to as the downflow regeneration method) and the downflow water/upflow regeneration method (hereinafter referred to as the upflow regeneration method). The downflow regeneration method is the most stable and simple regeneration method, but unregenerated impurities exist at the bottom of the resin layer after regeneration, and these impurities leak into the treated water during water flow, causing a decrease in the purity of the treated water. It also has the disadvantage of low regeneration efficiency. For example, to explain an ion exchange column filled with a strongly acidic cation exchange resin in a water purification device, calcium ions, When raw water containing ions such as magnesium ions and sodium ions is passed through in a downward flow, the arrangement of ion forms in the strongly acidic cation exchange resin layer at the end point of the water flow is from the upper layer to the lower layer: calcium, magnesium ions, etc. The sodium form is followed by the hydrogen form. This arrangement of ionic forms is due to the selectivity of each ion with respect to the strongly acidic cation exchange resin, but when regenerating a strongly acidic cation exchange resin layer with such an arrangement of ionic forms, it is necessary to use, for example, a regenerated chemical solution as it is. When an aqueous solution of hydrochloric acid is allowed to flow downward, the adsorbed sodium ions from the upper layer to the middle layer of the resin layer are desorbed, and the regenerated chemical solution containing impurities such as sodium ions flows into the lower layer of the ion exchange resin. By flowing down, sodium ions and the like are adsorbed again to the strongly acidic cation exchange resin in the hydrogen form located in the lower layer of the ion exchange resin. Therefore, since sodium forms are generated in the lower layer of the ion exchange resin after the regeneration, this sodium ion leaks into the treated water during water passage, resulting in a disadvantage that the purity of the treated water is reduced. The upflow regeneration method solves the drawbacks of the downflow regeneration method. In other words, when the regenerated chemical solution flows upward, the lower layer of the ion exchange resin is regenerated with the regenerated chemical solution that does not contain impurities such as sodium ions and calcium ions, so the lower layer of the ion exchange resin is completely regenerated into hydrogen form. Since the hydrogen-type ion-exchange resin present at the end of raw water flow can be retained in the lower layer of the resin, more hydrogen-type ion-exchange resin can be produced through regeneration, and unregenerated ion-exchange resin can be Since the calcium type and sodium type ion exchange resins exist only in the middle and upper layers of the resin layer, it is possible to obtain a larger amount of treated water with higher purity than with the downflow regeneration method during water flow. However, in the upward flow regeneration method, the flow of the resin bed during regeneration and the one-sided flow of the regenerated chemical solution cause a decrease in regeneration efficiency and a decrease in the purity of the treated water, so water or pressurized air is introduced from the top of the resin tower during regeneration. The drawbacks are that the device is complicated and operation is extremely difficult, such as requiring a special structure to prevent the flow of the ion exchange resin and a specially constructed distributor. The present invention solves the drawbacks of the conventional regeneration method in a single bed ion exchange column packed with a single strong electrolyte ion exchange resin. To regenerate the tower, the regenerated chemical solution is introduced in a downward flow from a liquid collection and distribution pipe provided in the ion exchange resin layer to regenerate the ion exchange resin layer below the liquid collection and distribution pipe,
A step of collecting the regenerated waste liquid, by causing the regenerated waste liquid to flow downward from the upper part of the ion exchange tower and discharging this effluent from the liquid collection and distribution pipe, thereby forming an ion exchange resin layer above the liquid collection and distribution pipe. This is a method for regenerating an ion exchange column, comprising the step of regenerating the ion exchange column. The present invention will be explained in detail below using the drawings. The figure is an explanatory diagram of a flow showing an example of an embodiment of the present invention. In the figure, 1 is an ion exchange tower in which an ion exchange resin layer 2 is formed, and a liquid collection and distribution pipe 3 and a Distributors 4 are disposed above the ion exchange resin layer 2, respectively. The liquid collection and distribution pipe 3 is connected to the recycled chemical liquid discharge pipe 13,
Further, the dilution water inflow pipe 14 and the regenerating chemical liquid tank 5 are communicated via the ejector 7 . The distributor 4 communicates with the recovery and regeneration drain tank 6 through a regeneration drain pipe 17 equipped with a pump 8 . In addition, at the top of the ion exchange tower 1, there is an inlet pipe 9 and an outlet pipe 1 for the water to be treated.
6, connect a pipe 10 to the lower part of the ion exchange tower 1, and further connect a backwash water inflow pipe 15, a treated water outflow pipe 11, and a recovery and regeneration drain pipe 12 to the pipe 10,
One end of the recovered and regenerated drain pipe 12 is connected to the recovered and regenerated drain tank 6 . When treating water with the above-mentioned apparatus, the water to be treated flows downward from the water inlet pipe 9 into the ion exchange tower 1, and the ion exchange resin layer 2 flows downward.
The treated water is made to flow out from the treated water outflow pipe 11. After the water to be treated flows downward, backwashing is performed depending on the pressure loss of the ion exchange resin layer and the degree of contamination due to turbidity. Backwashing is carried out by a normal backwashing method, in which backwash water is passed through the ion exchange tower 1 in an upward flow from the backwash water inflow pipe 15, the entire ion exchange resin layer 2 is backwashed, and the backwash wastewater is sent to the discharge pipe. Although the water may be discharged from the ion exchange resin layer 2 which is filled with turbidity, backwash water may be discharged from the liquid collection and distribution pipe 3.
It is also possible to backwash only the middle and upper parts of the tank. Next, the regenerated liquid and extruded water obtained by regenerating the ion exchange resin layer 2'' below the liquid collection and distribution pipe 3 in the previous cycle are stored in the recovery and regenerated liquid tank 6, and the regenerated liquid is used to operate the pump 8. The regenerated liquid is allowed to flow downward from the distributor 4 through the regeneration drain pipe 17 into the ion exchange tower 1, and the effluent is discharged from the liquid collection and distribution pipe 3 through the discharge pipe 13, and is discharged upward from the liquid collection and distribution pipe 3. The ion exchange resin layer 2' is regenerated. At this time, water is flowed into the ion exchange tower 1 from the backwash water inlet pipe 15 in an upward flow at a low flow rate so that the regenerated liquid does not flow into the ion exchange resin layer 2''. You may let them. Next, the extruded water is caused to flow downward into the ion exchange tower 1 from the water inflow pipe 9 to be treated, and the residual regenerated liquid in the ion exchange resin layer 2' is discharged from the liquid collection and distribution pipe 3 through the discharge pipe 13. Next, the new regenerated chemical solution in the regenerated chemical tank 5 is activated by the ejector 7 to flow downwardly into the ion exchange tower 1 from the liquid collection and distribution pipe 3 to regenerate the ion exchange resin layer 2'' located below the liquid collection and distribution pipe 3. The regenerated waste liquid is collected through the collected and regenerated liquid drain pipe 12 into the collected and regenerated liquid drain tank 6, and is used for the regeneration of the ion exchange resin layer 2' in the next regeneration process.The regeneration of the ion exchange resin layer 2'' is completed. After that, dilute the extruded water into the water inlet pipe 1
4, and descends from the collection and distribution pipe 3 to the ion exchange tower 1.
The regenerated liquid of the ion exchange resin layer 2'' is extruded, and this extruded waste water is also collected in the recovery and regeneration liquid tank 6 to be used for the next regeneration of the ion exchange resin layer 2'. The water may be passed downward from the treated water inlet pipe 9 to the ion exchange tower 1 to push out the regenerated liquid from the entire ion exchange resin layer 2, and then collected from the collected and regenerated liquid drain pipe 12 to the collected and regenerated liquid drain tank 6. Next, the water to be treated flows downward into the ion exchange tower 1 from the water inflow pipe 9 to wash the ion exchange resin layer 2, and the washed wastewater is passed through the outflow pipe 11 for the treated water.
Emit more. If the ion exchange tower 1 is, for example, a cation tower for a pure water production device filled with a strongly acidic cation exchange resin, monovalent cations such as sodium ions are present in the lower layer of the ion exchange resin layer 2 at the end of water flow. However, these sodium ions are easily eluted by the hydrogen ions of hydrochloric acid used as a regenerating chemical solution and regenerated into hydrogen form. In addition, since the regenerated chemical solution is passed and extruded in a downward flow from the liquid collection and distribution pipe 3 in the ion exchange resin layer 2, unlike the conventional down flow regeneration method, the regenerated chemical solution is eluted from the calcium form above the ion exchange resin layer 2. It does not contain impurities such as valent cations and is more completely regenerated into hydrogen form. In the present invention, the position of the liquid collection and distribution pipe 3 disposed within the ion exchange resin layer 2 depends on the quality of the water to be treated, the required quality of the treated water, the required amount of the treated water, the diameter of the ion exchange tower, the height of the resin bed, etc. However, it is usually desirable to arrange the resin layer between the lower one-third position and the upper half position of the total resin layer height. In addition, in this embodiment, in order to regenerate the ion exchange resin layer 2' above the liquid collection and distribution pipe 3, the recycled waste liquid of the ion exchange resin layer 2'' below the liquid collection and distribution pipe 3 collected in the previous cycle was used. However, prior to regenerating the ion exchange resin layer 2', the ion exchange resin layer 2'' may be regenerated with a new regenerating agent, and the ion exchange resin layer 2' may be regenerated using the recycled waste liquid. . According to the present invention, a liquid collection and distribution pipe is disposed within a strong electrolyte ion exchange resin layer, and the regenerated waste liquid obtained by regenerating the ion exchange resin layer below the liquid collection and distribution pipe is transferred to the ion exchange resin layer above the liquid collection and distribution pipe. By using it for regeneration, the amount of regenerated chemical solution can be reduced and the regeneration efficiency can be increased. At the same time, the lower layer of the ion exchange resin layer is regenerated with the regenerated chemical solution that does not contain impurities, so the lower layer of the ion exchange resin layer Highly purified treated water can be obtained without leaving unregenerated ion exchange resin in the water, and without leaking impurities into the treated water in the downstream flow. Further, the present invention has the advantage that the regenerating chemical solution is passed through the upper and lower layers of the ion exchange resin layer in a downward flow, so that a complicated device is not required and the treatment operation can be performed easily. Examples of the present invention will be described below. Example A column serving as an ion exchange tower with an inner diameter of 33 mm and a straight section height of 1000 mm was filled with 570 ml of Amberlite (registered trademark) IR-120B (resin bed height 666 mm) as a strongly acidic cation exchange resin, and was placed under the ion exchange resin layer. A liquid collection and distribution pipe with porous holes was installed internally at a height of 222 mm. When regenerating the ion exchange resin layer above the liquid collection and distribution pipe, a 5% hydrochloric acid solution was used to regenerate the ion exchange resin layer below the liquid collection and distribution pipe in the pre-regeneration process.
A total of 1,050 ml of 780 ml of recycled waste liquid and its extrusion waste water are collected in a collection and recycled liquid tank, and this recycled waste liquid is
1050 ml is passed through the ion exchange resin layer above the collection and distribution pipe at a downward flow rate of 4/h (SV) from above the column and discharged from the collection and distribution pipe, followed by raw water with the composition shown in Table 1. 570 ml of water was passed in a downward flow to perform extrusion, and the effluent was discharged from the liquid collection and distribution pipe to regenerate the ion exchange resin layer above the liquid collection and distribution pipe. Next, when regenerating the ion exchange resin layer below the liquid collection and distribution pipe, use 94ml of 36% hydrochloric acid as the regeneration chemical solution.
(d=1.18) was diluted to about 5% to 780 ml, and passed through the liquid collection and distribution pipe in a downward flow at a flow rate of 4/h (SV). Then, 270 ml of pure water was passed through the liquid collection and distribution pipe for extrusion. The lower ion exchange resin layer was regenerated. At this time, a total of 1050 ml of recycled waste water from the ion-exchange resin layer below the liquid collection and distribution pipe and extrusion waste water is collected in the recovery and regeneration liquid tank, and the ion-exchange resin layer above the liquid collection and distribution pipe will be used in the next regeneration process. Store for regeneration. Next, flow the raw water from above the column at
Water was passed through the column at a downward flow rate of 12/h (SV) for 30 minutes and discharged from the bottom of the column to wash the ion exchange resin layer. Thereafter, raw water was passed through in a downward flow at a flow rate of 20/h (SV). The end point of water flow is a separate, fully regenerated strong basic anion exchange resin Amberlite.
The treated water of this example was passed through a column filled with IRA-400, and the point was determined that the electrical conductivity of the water flowing out of the strongly basic anion exchange resin column reached 10 μυ/cm. The regeneration and water flow explained above are each performed 5 times.
When repeated several times, the average conductivity of the treated water was 2.0μ
The average throughput was 490/- resin. On the other hand, as a conventional method for comparison, using the same column, ion exchange resin, and amount as in the example of the present invention, 94 ml of 36% hydrochloric acid was diluted to about 780 ml of 5%, and the flow rate was 4/h ( SV) and then raw water with the composition shown in Table 1.
855 ml of water was forced out by flowing downward at a flow rate of 3.4/h (SV), and then this raw water was flowed in at a downward flow at a flow rate of 12/h (SV) for 30 minutes for pre-cleaning. Next, this raw water was passed through in a downward flow at a flow rate of 20/h (SV). The end point of the water flow was set as the point at which the electrical conductivity of the water flowing out of the strongly basic anion exchange resin column reached 10 μυ/cm in the same manner as in the examples of the present invention. When the above regeneration and water flow were repeated 5 times each, the average conductivity of the treated water was 4.7μυ/cm, and the average treatment amount was
470/- It was resin. In addition, in both the present invention and the conventional method, when the water flow was finished, the regeneration was performed without performing backwashing. As shown in the above results, the present invention was superior to the conventional method in terms of treated water quality and throughput. 【table】

[Brief explanation of the drawing]

The figure is an explanatory diagram of a flow showing an example of an embodiment of the present invention. 1...Ion exchange tower, 2...Ion exchange resin layer, 3...Liquid collection and distribution pipe, 4...Distributor, 5...Regenerating chemical liquid tank, 6...Recovery and regenerating waste liquid tank,
7... Ejector, 8... Pump, 9... Treated water inflow pipe, 10... Pipe, 11... Treated water outflow pipe, 12... Recovery and regeneration drain pipe, 13... Regeneration chemical solution discharge pipe, 14 ...Dilution water inflow pipe, 15...Backwash water inflow pipe, 16...Discharge pipe, 17...Regeneration drain pipe.

Claims (1)

[Claims] 1. When regenerating a single-bed ion exchange tower filled with a single strong electrolyte ion exchange resin, the regenerated chemical solution is allowed to flow downward from the liquid collection and distribution pipe provided in the ion exchange resin layer, and is then flowed downward from the liquid collection and distribution pipe. A step of regenerating the ion exchange resin layer in the ion exchange column and collecting the regenerated effluent, by causing the regenerated effluent to flow downward from the upper part of the ion exchange tower and discharging the effluent from the liquid collection and distribution pipe. A method for regenerating an ion exchange tower, comprising a step of regenerating an ion exchange resin layer above a liquid collection and distribution pipe.