JPS6010677Y2 - Ion exchange tower used for upstream regeneration - Google Patents

Description

[Detailed description of the invention] This invention forms a multi-layered bed filled with a weak electrolyte ion exchange resin in the upper layer and a strong electrolyte ion exchange resin in the lower layer in an ion exchange tower, and performs ion exchange treatment in a downward flow. This invention relates to an ion exchange tower that regenerates the multilayer bed using a regenerating agent such as acid or alkali in an upward flow.

In the regeneration of conventional multi-bed ion exchange towers, a collector for discharging regeneration waste liquid is buried slightly below the upper surface of the weak electrolyte ion exchange resin in the upper layer, and the regenerating agent and extruded water are flowed upward from the bottom of the ion exchange tower. At the same time, a fluid such as air or water is allowed to flow in from the upper part of the column, and both the fluid and the recycled waste liquid are discharged from the collector, and the resin layer is pressed and held by the inflow pressure of the fluid for regeneration. Do the following.

However, when regenerating with such a conventional ion exchange tower, the following problems occur.

In other words, when upstream regeneration is performed in the ion exchange tower described above, the collector installed above the ion exchange resin layer collects the fluid flowing from the top of the ion exchange tower and the regenerated waste liquid rising from the bottom of the ion exchange tower. will flow in at the same time,
The ion exchange resin around the collector is pressed against the collector, and an adhesive layer of ion exchange resin (hereinafter referred to as blocking) is formed around the collector.

) is formed. On the other hand, when a weak electrolyte ion exchange resin changes from a saturated type to a regenerated type, its volume decreases significantly (approximately 50% in the case of a weakly acidic cation exchange resin and approximately 20% in the case of a weakly basic anion exchange resin). In order to account for this decrease in volume, it is necessary to fill the upper part of the collector with extra weak electrolyte ion exchange resin and start upward regeneration. However, as mentioned above, during regeneration, weak electrolyte Blocking of ion exchange resin is formed,
This blocking prevents the weak electrolyte ion exchange resin filled in the upper part of the collector from falling to the lower part.

Therefore, a space is formed in the ion exchange resin layer at the bottom of the collector by the volume reduction of the weak electrolyte ion exchange resin. The disadvantage is that the layer becomes fluidized.

During upflow regeneration, if the strong electrolyte ion exchange resin in the lower layer becomes fluidized, the salt-type ion exchange resin will remain at the bottom of the ion exchange resin layer, which may reduce the purity of the treated water or reduce the yield. may decrease.

In particular, in multi-layer beds, the amount of regenerant used is minimized, so even a slight fluidization of the ion exchange resin will have a significant effect.

In addition, when forming such a multilayer bed, both ion exchange resins are separated by backwashing using the density difference between the weak electrolyte ion exchange resin and the strong electrolyte ion exchange resin, but depending on the ion exchange resin used, Since the densities of both ion exchange resins are similar, backwash separation may be impossible.

Therefore, the ion exchange resin used has the disadvantage that it is limited to some extent by its density.

The present invention solves these shortcomings of conventional ion exchange towers, and prevents fluidization of the strong electrolyte ion exchange resin in the lower layer during upflow regeneration, and uses both ion exchange resins with similar densities. The purpose of the present invention is to provide an ion exchange column that can always form a complete multilayer bed even when using

In other words, the ion exchange tower used for the upflow regeneration of the present invention is filled with a weak electrolyte ion exchange resin in the upper part of the ion exchange tower, a strong electrolyte ion exchange resin in the lower part, and the interface between both ion exchange resins. In addition, a shield plate is installed horizontally that can move up and down while rubbing against the inner wall of the ion exchange tower, allowing liquid to pass through but not allowing the ion exchange resin to pass through. Furthermore, the regenerant flows into the bottom of the strong electrolyte ion exchange resin packed bed. The pipe is characterized in that a recycled waste liquid discharge pipe is attached to the upper part of the weak electrolyte ion exchange resin packed bed.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the structure of an ion exchange tower that is an example of an embodiment of the present invention. In the figure, 1 is an ion exchange tower, and inside the tower there is a shield that can be moved up and down while rubbing against its inner wall. A plate 4 is attached, and this shielding plate 4 has a large number of holes 18 with a diameter of 10 to 30 m, and has a diameter slightly smaller than the inner diameter of the ion exchange column 1, and is a disc-shaped batten made of steel plate or synthetic resin. For example, 40 to 65 mesh Saran cloth 6 is placed on the top surface of 5.
A reinforcing plate 8 is attached perpendicularly to the outer periphery of the plate 5, and at two or more locations on the outer periphery of the reinforcing plate 8,
For example, by attaching a guide plate 7 with a length of 20 to 50 cm and a width of 10 to 300 cm, the shielding plate 4 can be attached to the ion exchange tower 1 and can be moved horizontally smoothly without tilting when moving up and down. I can do it.

Further, it is recommended to attach a sealing material 16 such as a rubber seal around the lower surface of the batten 5 so that its outer periphery protrudes slightly outward from the reinforcing plate 8 and the guide plate 7. 1 to completely seal the shielding plate 4 and the inner wall of the ion exchange column 1.

In addition, by making the frictional force generated between the sealing material 16 and the inner wall of the ion exchange tower 1 larger than the hydraulic pressure applied to the shielding plate 4 due to the upward flow of the regenerant and extruded water, the upward flow of the regenerant and extruded water increases. By keeping the shielding plate 4 horizontally within the ion exchange tower 1 without moving upwards due to the flow, and by making the frictional force smaller than the hydraulic pressure applied to the shielding plate 4 due to the rise of the backwash water, the reverse The shielding plate 4 can be moved upward by the upward flow of washing water.

In addition, a supporting bed 1 of ion exchange resin is placed at the bottom of the ion exchange column 1.
5 is provided, and a treated water outflow pipe 13 and a regenerant inflow pipe 14 are connected to the lower part of the support bed 15, and a distribution pipe/collection pipe 10 is provided above the ion exchange column 1, and the treated water flow is connected to the pipe 10. The inlet pipe 11 and the recycled waste liquid discharge pipe 12 are communicated.

In addition, a stopper 9 is provided at the upper limit of movement of the shielding plate 4,
As shown in Fig. 2, the shielding plate 4 is moved to the stopper 9 using backwash water, so that the strong electrolyte ion exchange resin 2 below the shielding plate 4 to be filled can be sufficiently expanded by backwashing as described later. At the same time, a backwash wastewater discharge pipe 17 is communicated with the ion exchange tower 1 slightly below the shielding plate 4 that has reached the stopper 9.

In such an ion exchange tower 1, for example, treated water is supplied in an upward flow from the treated water outflow pipe 13, the shielding plate 4 is moved and held at the stopper 9 position, and backwash wastewater is discharged below the shielding plate 4. The strong electrolyte ion exchange resin 2 is filled through the pipe 17, and then the water to be treated or the treated water is allowed to flow downward from the distribution pipe/collection pipe 10 through the water inflow pipe 11,
The shielding plate 4 is moved horizontally below the backwashing wastewater discharge pipe 17, and the weak electrolyte ion exchange resin 3 is filled above the shielding plate 4 from the backwashing wastewater discharge pipe 17, thereby forming a boundary between both ion exchange resins. A shielding plate 4 is placed on the surface.

When water is passed through this ion exchange tower, first, the water to be treated or the treated water is passed through the water to be treated through the inlet pipe 11 and the distribution pipe/collection pipe 10 at a downward flow velocity that allows the shielding plate 4 to move downward. Water shield plate 4 and ion exchange tower 1
is lowered while rubbing the inner wall of the shield plate 4, and the strong electrolyte ion exchange resin 2 below the shield plate 4 is pushed down, and the strong electrolyte ion exchange resin 2 is tightly fixed by the shield plate 4 so that there is no space.

Next, the strong electrolyte ion exchange resin 2 is applied to the shielding plate 4 in this way.
With the water fixed at is discharged from the treated water outflow pipe 13.

When the ion exchange capacity of both ion exchange resins decreases, regeneration is performed.

That is, the regenerant is supplied from the regenerant inlet pipe 14 to the strong electrolyte ion exchange resin 2 at a normal flow rate, for example, a linear velocity of 3 to 10 m/min.
Flow in with an upward flow of H.

At this time, the hydraulic pressure of the upward flow of regenerant is applied to the shielding plate 4, but
Since the frictional force generated between the sealing material 16 of the shielding plate 4 and the inner wall of the ion exchange column 1 is greater, the shielding plate 4 does not move upward and can be held at the position before the start of regeneration. It is possible to efficiently regenerate the strong electrolyte ion exchange resin 2 while keeping it fixed without fluidizing it.

The regenerant that has passed through the strong electrolyte ion exchange resin 2 is passed through the shielding plate 4
The weak electrolyte ion exchange resin 3 is fluidly regenerated by the upward flow of this regenerating agent.

Since the weak electrolyte ion exchange resin 3 has excellent regeneration efficiency, it can be sufficiently regenerated even in a fluidized state without forming a fixed bed, and the weak electrolyte ion exchange resin 3 can be backwashed at the same time as the regeneration. .

Note that the recycled waste liquid is discharged from the recycled waste liquid discharge pipe 12.

When the regenerating agent has finished flowing, extruded water is introduced from the regenerating agent inflow pipe 14 to push out the regenerating agent remaining in both ion exchange resins, which is then discharged from the regenerated waste liquid discharge pipe 12.

Note that in this extrusion as well, the hydraulic pressure of the extruded water is applied to the shielding plate 4 in the same way as when passing the regenerant, but since the frictional force is greater, the shielding plate 4 does not move upward.

After this extrusion is completed, the material is washed with the aforementioned downward flow of water, and the aforementioned water flow treatment is performed again.

As mentioned above, the weak electrolyte ion exchange resin 3 can be backwashed at the same time as the regeneration, but since turbidity gradually accumulates in the strong electrolyte ion exchange resin 2 and pressure loss increases, it is necessary to backwash the weak electrolyte ion exchange resin 3 once every few cycles. Strong electrolyte ion exchange resin at the rate of 2 times
Perform backwashing.

When backwashing the strong electrolyte ion exchange resin 2, prior to passing the regenerant as described above, a high flow rate of backwash water is applied to the regenerant inlet pipe 1.
4. Let the flow flow upward.

The hydraulic pressure applied to the shielding plate 4 due to the inflow of the backwashing water becomes greater than the frictional force generated between the sealing material 16 of the shielding plate 4 and the inner wall of the ion exchange tower 1. , the shielding plate 4 can be gradually moved upward, and the shielding plate 4 is pushed up to the stopper 9 as shown in FIG.

This allows the strong electrolyte ion exchange resin 2 below the shielding plate 4 to be sufficiently backwashed and expanded.

The backwash wastewater is discharged from the backwash wastewater discharge pipe 17 together with the suspended solids accumulated in the strong electrolyte ion exchange resin 2.

Note that the weak electrolyte ion exchange resin 3 above the shield plate 4 is pushed up above the ion exchange tower 1 as the shield plate 4 rises, and is held in a state separated from the strong electrolyte ion exchange resin 2 by the shield plate 4.

When the backwashing of the strong electrolyte ion exchange resin 2 is completed, the inflow of the backwash water is stopped, and after the strong electrolyte ion exchange resin 2 is calmed down, the water to be treated or the treated water is transferred to the water inlet pipe 11.
The flow is caused to flow through the distribution pipe/collection pipe 10 with a downward flow at a high velocity that can move the shielding plate 4 downward.
While allowing the outflow water to flow out from the treated water outflow pipe 13, the shielding plate 4 located at the stopper 9 is moved downward, and the first
As shown in the figure, a weak electrolyte ion exchange resin 3 is placed on a shielding plate 4.
At the same time, the strong electrolyte ion exchange resin 2 is tightly fixed with the shielding plate 4 so that there are no spaces.

After that, the above-mentioned regeneration process is performed.

The shield plate in the ion exchange tower of the present invention can be of any shape as long as it can move up and down while rubbing against the inner wall of the ion exchange tower and has a structure that allows liquid to pass through but not ion exchange resin. Usually, in this embodiment, a batten with many holes and a Saran cloth stretched over the top surface was used.
Saran cloth can be stretched on the bottom or both sides of the batten, or Saran cloth can be sandwiched between two batten boards, or Saran cloth can be layered with wire mesh and fixed to a reinforcing board. ').

In addition, a highly elastic sealing material such as a rubber packing or an oil seal is used to sufficiently seal the shielding plate and the inner wall of the ion exchange tower to prevent the two ion exchange resins from mixing.

In addition, the frictional force between the sealing material and the inner wall of the ion exchange tower may be affected by the shielding plate 4 depending on the upward flow of the regenerant and extruded water.
The material and shape of the sealing material can be adjusted so that the shielding plate does not move and the shielding plate moves due to the inflow of high-velocity backwash water.

As explained above, the ion exchange tower of the present invention can regenerate the strong electrolyte ion exchange resin without fluidizing it during upflow regeneration, and can efficiently regenerate the weak electrolyte ion exchange resin using the recycled waste liquid of the strong electrolyte ion exchange resin. can be played.

In addition, since the weak electrolyte ion exchange resin and the strong electrolyte ion exchange resin are completely separated by a shielding plate, it is possible to select the optimal both ion exchange resins and form a multilayer bed regardless of the density of both ion exchange resins. I can do it.

Furthermore, since the shielding plate can be moved by the hydraulic pressure of backwash water, sufficient backwashing can be achieved without discharging the strong electrolyte ion exchange resin outside the tower.

Furthermore, the structure of the shielding plate of the ion exchange tower of the present invention is simple and can be manufactured at low cost.

[Brief explanation of the drawing]

The drawings are explanatory diagrams showing the structure of an ion exchange tower used for upflow regeneration, which is an example of an embodiment of the present invention. Fig. 1 shows the state during water flow, and Fig. 2 shows the state during backwashing. It shows. 1... Ion exchange tower, 2... Strong electrolyte ion exchange resin, 3... Weak electrolyte ion exchange resin, 4... Shielding plate, 5... ... batten, 6.
... Saran cloth, 7 ... Information board, 8 ...
...Reinforcement plate, 9...Stopper, 1o...
...Distribution pipe and collection pipe, 11...Water to be treated inflow pipe, 12...Recycled waste liquid discharge pipe, 13...
- Treated water outflow pipe, 14... Regenerant inflow pipe, 15
... Support floor, 16 ... Sealing material, 17
...Backwash wastewater discharge pipe, 18...hole.

Claims (1)

[Scope of utility model registration request] A weak electrolyte ion exchange resin is filled in the upper part of the ion exchange tower, and a strong electrolyte ion exchange resin is filled in the lower part of the ion exchange tower, and at the interface of both ion exchange resins, the inner wall of the ion exchange tower is rubbed up and down. A movable shielding plate that allows liquid to pass through but not ion exchange resin is attached horizontally, and a regenerant inflow pipe is installed at the bottom of the strong electrolyte ion exchange resin packed bed and above the weak electrolyte ion exchange resin packed bed. An ion exchange tower used for upflow regeneration, characterized in that each regeneration waste liquid discharge pipe is attached.