JPS5931377B2 - How to control ion exchange equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the operation of a moving bed ion exchange apparatus, particularly a moving bed mixed bed ion exchange apparatus.

In general, moving bed mixed bed ion exchange equipment uses a mixture of strongly acidic cation resin and strong basic anion resin, and because it produces highly purified water with very little residual electrolyte, it is suitable for boiler supply water. It has been widely adopted as a processing method.

Conventionally, the operation management method for this type of equipment is that the amount of water passed is determined by the quality of raw water and the amount of ion exchange resin circulated, so treatment is performed under almost constant operating conditions without major changes, and the water is processed about once a day. By measuring the electrical conductivity in the raw water, the amount of resin circulation or regeneration agent can be changed accordingly.

However, when the water quality of raw water fluctuates drastically during dry seasons or heavy rains, it is not possible to follow the fluctuations and obtain a stable quality of treated water, and it is necessary to use regeneration chemicals to always manage on the safe side. The amount was large and it was uneconomical.

□ The present invention was made to solve the above problems, and aims to provide ion-exchanged water with stable water quality, rationalization of work, and a control method for ion exchange equipment that uses less chemicals. It is something.

That is, the present invention provides a moving bed ion exchange device that includes:
A means for detecting the water flow rate, the conductivity of the raw water, and the silica value of the ion-exchanged water, and calculating the amount of regeneration agent to be injected into the regeneration tower based on the water flow rate and the conductivity, and converting the calculated value into the silica value. A method for controlling an ion exchange apparatus, comprising: a computation means for correction, and an amount of regenerating agent to be injected is adjusted based on a computed value of the computation means.

The present invention will be explained below with reference to the drawings.

Raw water is led to water flow rate 1 through pipe 2, and while this raw water passes through the resin layer in water flow rate 1 due to an upward flow, the resin layer is pushed up to the top of the tower to form a bed, and the water that has undergone ion exchange is It is discharged through screen 3 at the top of the column.

On the other hand, the resin that has undergone ion exchange is pumped together with the raw water from the lower part of the tower to the separation tower 5 through the pipe 4 due to the internal pressure generated by the raw water introduced into the water flow rate 1.

At water flow rate 1, the water flow valve 6 is closed by a timer at regular intervals, and at the same time, the drain valve 7 is opened, and the water within the water flow rate 1 is drained from the lower part of the tower, and the check valve 8 at the top of the tower is automatically opened. Then, the recycled resin stored in the mixing hopper 9 flows into the tower and fills the water flow rate 1.

Since the internal pressure of this radical decreases, the pressure feeding of the resin to the separation column 5 is stopped, and the mixing hopper 9 is filled with cation exchange resin (r
cERJ) and anion exchange resin (rAER)
Regenerated resin (referred to as J) is supplied through the cation resin hopper 12 and the anion resin hopper 13 by the pressure inside the regeneration towers 10 and 11, respectively.

When the water drain valve 7 is closed by a timer at several tens of sand diameters, the water flow valve 6 is simultaneously opened again, raw water is introduced again, and water flow begins.

The resin sent to the separation column 5 is separated into CER and AER by separated water at a constant flow rate from the pipe 14. CER is taken out from the bottom of the separation column 5 and AER is taken out from the top of the separation column 5. CER regeneration tower hopper 15 and AER
It is sent to the regeneration tower hopper 16.

In the CER regeneration tower 10, dilute hydrochloric acid is introduced through a pipe 17, and in the AER regeneration tower 11, an aqueous sodium hydroxide solution is introduced as a regeneration agent through a pipe 18, respectively, to regenerate the ion exchange resin.

Further, replacement water is led from the lower part of each regeneration tower 10, 110 through pipes 19, 20, and resin is taken out and filled in the same principle as in the water tower 1 described above.

During such operation, signals corresponding to the conductivity of the raw water by the conductivity meter 21 and the amount of treated water by the flow meter 22 are input to the calculator 23.

Next, in the calculator 23, the total anion amount TA and the total ion amount TC are calculated using a preset functional formula from the conductivity μ (for example, TA=a1μ+b□, TC=
a2μ+b2. al, a2. bl, b2 are coefficients) This T
A and TC, the flow rate F detected by the flow meter 22, and the ratio of each regenerating agent Ao, Co (ion exchange equivalent of the chemical (in terms of CaCO2)/ion exchange equivalent of the raw water (in terms of CaCO3))] Determine the amount of regeneration agent such as the amount H and the amount N of sodium hydroxide.

(For example, H=a3XFXTCXC02N=a4XFXT
AXAo, a3ta4 are coefficients) Next, the preset silica value (for example, 0.03 to 0.07 ppm
) and a fixed time interval (for example, 15 to 45
The ratio of each regenerating agent described above is changed according to the difference from the set position (for example, if the silica value is Q, Q7 ppm or more, C0tAO is increased by a certain ratio). , if it is 0.03 ppm or less, it is reduced at a certain rate.

) Correct the amount of each regeneration agent according to the above formula.

The amount of each regeneration agent is sent to the pumps 25 and 26, and by changing the stroke of the pump, the regeneration tower 10゜1
The operation of the ion exchange device is controlled by changing the amount injected into 1.

Of course, it goes without saying that the amount of regeneration agent can be controlled by using a control valve instead of changing the stroke of the pump.

Further, the formulas for determining the above-mentioned TA, TC, H, N, etc. can be arbitrarily determined depending on the processing capacity of the apparatus, the target raw water, etc.

In this way, the present invention is a method of changing the amount of regenerating chemicals in response to changes in the quality of raw water, but in addition to this, it is also possible to change the interval of the timer that controls the water flow valve 6, drain valve 7, etc. It is also possible to consider a method in which the amount of water taken or the amount of resin circulation is changed by changing the amount of water taken or the amount of resin circulated.

However, if this method is adopted, the resin in each group will become slack, resulting in a decrease in efficiency, and it will be necessary to change the displacement water, the opening degree of the resin transfer valve, etc., and the control system will become complicated, which is not preferable.

As a result of implementing the method of the present invention as described above, treated water having a nearly constant silica value was always obtained, and moreover, the amount of regeneration agent was able to be reduced by about 10% compared to the examples of the present invention. .

As described above, the method of the present invention can always obtain treated water of stable quality even if the quality of raw water changes significantly, can reduce the amount of regeneration chemicals, and can streamline the work. This is an extremely excellent method industrially.

[Brief explanation of drawings]

The figure is an outline of the flow related to the ion exchange device. In the figure, 1 is a water tower, 5 is a separation tower, 10° and 11 are regeneration towers, and 23 is a computing unit.

Claims (1)

[Claims] 1. In a moving bed type ion exchange device, means for detecting the water flow rate, the conductivity of raw water, and the silica value of ion exchange water, and calculating the amount of regeneration agent injected into the regeneration tower based on the water flow rate and conductivity. A method for controlling an ion exchange device, comprising: a calculation means for correcting the calculated value by a silica value, and an amount of regenerating agent to be injected is adjusted based on the calculation value of the calculation means.