JP3598656B2 - Ion exchange resin ion composition measuring device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for measuring the ion composition of an ion exchange resin for measuring the proportion of a sulfate ion type resin in an anion exchange resin in a sample resin containing the anion exchange resin. More specifically, the present invention relates to an ion composition measuring apparatus suitable for measuring a sulfate ion composition of a regenerated resin of an ion exchange resin layer used in an ammonia type condensate desalination apparatus.
[0002]
[Prior art]
Ammonia-type condensate desalination system is designed to pass ammonia-containing condensate through a mixed bed of H-type cation exchange resin and OH-type anion exchange resin, so that impurity ions such as sodium ions and chlorine ions in the condensate are condensed. The H-type cation exchange resin is normally used (when there is no abnormality such as seawater leak) because it contains almost no impurities such as sodium ion and chlorine ion. Even if the water is saturated by water, regeneration is not performed, and water is passed in the form of ammonia. In general, the operation is stopped due to the pressure difference loss due to the resin clad capture, and the resin is regenerated.
[0003]
The resin is regenerated by separating the cation exchange resin and the anion exchange resin by backwashing the mixed bed (upflow washing), separately pouring the sulfuric acid aqueous solution into the cation exchange resin, An alkali solution such as sodium hydroxide is injected into the anion exchange resin to regenerate the cation exchange resin into the H form and the anion exchange resin into the OH form.
[0004]
However, if the separation of the resin in the regeneration is not complete, the resin that has been reversely recycled will remain. For example, when regeneration is performed with sulfuric acid in a state where the anion exchange resin is mixed with the cation exchange resin, the mixed anion exchange resin becomes a sulfuric acid form. Similarly, when regeneration is performed with sodium hydroxide in a state where the cation exchange resin is mixed in the anion exchange resin, the mixed cation exchange resin becomes a sodium form.
[0005]
Generally, the quality of treated water of an ion exchange device is determined by the ionic composition of the resin used. Therefore, during the regeneration of the resin, if a large amount of reverse regenerated resin has been generated, even if the washing is performed, the treated water quality will not be the purity suitable for the condensate treatment, Abnormalities such as discharging more corrosive components than usual occur. Conventionally, as these abnormality detection methods, the quality of the treated water after actually passing water is used to determine the quality, so a large amount of washing water is required, and in some cases, the purity is low (more than the control value). The treated water (containing corrosive components) may leak to the boiler. The above problem can be solved by measuring the ionic composition of the resin after regeneration at every regeneration and detecting defective regeneration before passing water.However, conventionally, there is only a method of manual analysis, and time and cost are reduced. Thus, it is almost impossible to measure the resin ion composition at every regeneration.
[0006]
As a method for measuring the sodium ion fraction of the mixed ion exchange resin in the ammonia type condensate desalination apparatus, an eluent is passed through a column filled with a sample resin, and the sodium content is determined from the change over time in the sodium concentration of the eluent. A measuring method has been proposed (Japanese Patent Publication No. 3-10376).
However, since no apparatus for measuring the sulfuric acid concentration has been obtained, the above method cannot be applied to the measurement of the sulfate ion composition of the anion exchange resin.
[0007]
In general, since the ion concentration has a correlation with the electric conductivity, the ion concentration is measured by measuring the electric conductivity. However, when the sulfate ion is eluted by contacting the anion exchange resin on which the sulfate ion is adsorbed with an eluent such as an aqueous ammonia solution, when the sulfate ion composition of the anion exchange resin is less than 40%, the amount of the sulfate ion eluted is reduced. And the sulfate ion composition of the anion exchange resin cannot be accurately measured.
[0008]
FIG. 3 shows the sulfate ion composition R-SO ₄ of the anion exchange resin when the sulfate ion is eluted by bringing the anion exchange resin containing sulfate ions into contact with 0.3 mg / l, 1 mg / 1, and 3 mg / l aqueous ammonia. %) And the concentration of the eluted sulfate ion (leak SO ₄ ) (μg / l), showing that there is no substantial difference in the eluted ion when the sulfate ion composition is less than 40%.
However, in actual ion-exchange apparatus, unless there is no abnormality during playback, R-SO ₄ is 10 to 35 wt%, in such a sulfate ion composition, to accurately measure the sulfate ion composition of the anion exchange resin Can not.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to solve the above problems by measuring the sulfate ion composition of the anion exchange resin quickly, accurately and at low cost with a simple apparatus and method even when the sulfate ion composition is less than 40%. It is an object of the present invention to provide a device for measuring the ion composition of an ion exchange resin.
[0010]
[Means for Solving the Problems]
The present invention provides an elution tank for introducing a sample resin, bringing the sample into contact with sulfate ions in an amount such that the sulfate ion composition becomes 40% or more, and further bringing the sample resin into contact with an eluent to elute ions adsorbed on the resin;
A sulfuric acid supply path for supplying sulfuric acid to the elution tank,
An eluent supply path for supplying an eluent to the elution tank,
A cation exchange column for receiving a part of the eluent in the elution tank and performing cation exchange,
A conductivity meter for measuring the conductivity of the effluent of the cation exchange column,
The sulfate ion concentration in the eluent is calculated from the measured value of the conductivity meter by the following equation (1) or an equation including the equivalent equation, and the following equation (2) or an equation including the equivalent equation is calculated from the calculation result. Calculates the sulfate ion composition in the sample resin by first subtracting the amount of sulfate ions introduced into the elution tank and adsorbed on the anion exchange resin, thereby calculating the sulfate ion composition in the sample resin before sulfate ion adsorption. An ion composition measuring device for an ion exchange resin, comprising: an arithmetic device.
_{SO 4 = (1000 × S +} { [1000 × S] ² -4 × [2 × L1 + L2] ^{× L3 × 0.5 × 10 -14}} 1/2) / (2 × [2 × L1 + L2]) ...・ (1)
(1) where:
SO ₄ : SO ₄ concentration [eq / l]
S: conductivity [ms / m]
L1: H ion equivalent conductivity
L2: equivalent conductivity of SO ₄ ion
L3: Equivalent conductivity of OH ion
[SO ₄ ] = (1 / k2) × ([R-SO ₄ %] / [R-OH]) × [NH ₄ ] (2)
(2) where
[SO ₄ ]: Eluent SO ₄ concentration (eq / l)
k2 : Selection coefficient of OH and SO ₄
[R-SO ₄ %]: ratio of SO ₄ ions adsorbed on the resin
[R-OH]: ratio of OH ions adsorbed on the resin
[NH ₄ ]: concentration of NH ₄ inflow (eq / l)
R-OH + R-SO ₄ = 1 (100%)
[0011]
In the present invention, the sample resin to be measured is an anion exchange resin, and a single anion exchange resin or a mixture of an anion exchange resin and a cation exchange resin can be measured. Further, the resin after regeneration in a condensate desalination apparatus, particularly an ammonia type condensate desalination apparatus, is suitable as a target. In this case, the regenerated anion exchange resin can be used alone or as a sample resin in a state of being mixed with the cation exchange resin.
[0012]
If the resin after regeneration has been completely separated from the anion exchange resin and the cation exchange resin prior to regeneration, the resin having the opposite ionicity will not be included, so the reverse regenerated resin will not be generated, but the separation will not occur. When the resin is incomplete, the resin having the opposite ionicity is contained, so that a reverse regenerated resin is generated. In the present invention, it can be used for detecting a reproduction failure due to the generation of the reverse reproduction resin. In the case of a condensate desalination apparatus, the resin is regenerated with an aqueous solution of sulfuric acid for the cation exchange resin and an aqueous solution of sodium hydroxide for the anion exchange resin.
[0013]
Such regeneration failure often occurs in either the cation exchange resin or the anion exchange resin. When measuring only the anion exchange resin after regeneration, the sulfate ion composition due to incomplete regeneration of the anion exchange resin is measured. When the measurement is performed in a state in which the anion exchange resin and the cation exchange resin are mixed, the regeneration failure due to the incomplete separation and the sulfate ion composition due to the incomplete regeneration are measured.
[0014]
The sample resin is usually introduced into the elution tank by introducing 0.1 to 10 liters, preferably 0.5 to 2 liters, for measurement. In the case of a mixture of an anion exchange resin and a cation exchange resin, the amount of each resin is determined in advance, and the injection amount of the drug is determined based on the amount.
As the sulfuric acid to be brought into contact with the sample resin, an aqueous solution of 1 to 10% by weight of sulfuric acid can be used. In this case, it is preferable to use an aqueous solution of sulfuric acid as a regenerant. The amount of sulfuric acid is such that the sulfate ion composition in the anion exchange resin is at least 40%, preferably 45 to 80%.
The eluent to be brought into contact with the sample resin is for eluting sulfate ions, and is preferably an ammonia-containing water, and is preferably an aqueous ammonia solution of 0.1 to 20% by weight, preferably about 10% by weight.
[0015]
The elution tank has a sample resin layer so that the sample resin is brought into contact with sulfuric acid to convert the anion exchange resin into a sulfuric acid form, and further contacted with an eluent to elute the sulfate ions adsorbed on the resin. A structure in which the sample resin is brought into contact with a sulfate ion or an eluent under stirring so as to reach an equilibrium in the inside is preferable, but a liquid-flow type may be used. It is preferable that the liquid in the tank after contact with sulfuric acid is discharged as it is from the tank as it is, and the eluent eluted by contact with the eluent is taken out of the tank in a state separated from the sample resin.
[0016]
Cation exchange columns adsorb cations in the eluent. The cation exchange resin to be filled therein may be a strongly acidic resin having a neutral salt decomposability, and its use amount is usually about 1 to 10 liters, preferably about 2 to 4 liters. When a mixed resin is used as the sample resin, an anion exchange column can be provided to measure the ionic composition of the cation exchange resin, and anion in the eluent can be adsorbed. The anion exchange resin to be filled therein may be a strong basic resin having a neutral salt decomposability, and its use amount is usually about 0.1 to 3 liters, preferably about 0.5 to 2 liters.
[0017]
A conductivity meter is provided to measure the conductivity of the effluent of the cation exchange column. When an anion exchange column is provided, a measuring device can be provided to measure the conductivity or ion concentration of the effluent.
[0018]
It is preferable that the arithmetic unit calculates the sulfate ion in the eluent from the measured value of the conductivity meter, and calculates the sulfate ion composition of the anion exchange resin in the sample resin from this value. When a mixed resin is used, it can be configured to calculate a cation composition such as sodium ion from a measured value of a measuring device provided in the anion exchange column.
[0019]
In the measuring method using the above apparatus, first, a sample resin is introduced into an elution tank, and after draining water, sulfuric acid such as a sulfuric acid aqueous solution is introduced to convert the anion exchange resin into a sulfuric acid form. After draining the solution in the tank, an eluent such as ammonia-containing water is introduced and brought into contact with the sample resin to elute the sulfate ions exchanged and adsorbed on the sample resin. When the cation exchange resin is mixed, cations are also eluted, but when the eluent is ammonia-containing water, ammonium ions are exchange-adsorbed to the cation exchange resin in the sample resin, thereby causing other cations such as sodium ions to be adsorbed. Is eluted, and the pH of the resin becomes high due to the adsorption of ammonium ions, whereby sulfate ions exchanged and adsorbed on the anion exchange resin are also eluted and flow out into the eluent. Such an elution operation is continued until equilibrium is reached. The contact time with sulfuric acid and the eluent varies depending on the amount of the sample resin, the kind of the eluent, the concentration, etc., but is generally about 1 to 30 minutes, preferably about 5 to 20 minutes.
[0020]
By passing the eluate eluted in the elution tank as described above through a cation exchange column, cations in the eluate are exchanged and removed, and a solution containing sulfate ions flows out. It is measured by a meter. In the case of a resin mixed with a cation exchange resin, an eluent is injected without injecting sulfuric acid, and a part of the eluate in the elution tank is passed through an anion exchange column, whereby anions (acids) in the eluate are reduced. The eluate containing the cations such as sodium ions is exchanged and removed, and the conductivity or ion concentration of the effluent is measured by a measuring instrument.
[0021]
These measurement signals are input to an arithmetic unit, and the sulfate ion concentration in the eluate is calculated from the conductivity of the effluent, and the sulfate ion composition in the sample resin is calculated based on the calculation result. In this case, the calculation is performed such that the amount of sulfate ion first introduced into the elution tank and adsorbed on the anion exchange resin is subtracted. In the case of a mixed resin, to measure the cation composition, the cation composition of the sample resin is calculated based on the conductivity measured by a conductivity meter. The arithmetic unit determines the presence or absence of a reproduction failure based on the result, and the result is displayed on a display device. If the reproduction is defective, an alarm is issued.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system diagram showing an apparatus for measuring the ion composition of an ion exchange resin according to one embodiment.
[0023]
In FIG. 1, an elution tank 1 introduces an anion exchange resin or an anion exchange resin mixed with a cation exchange resin as a sample resin 2 in an amount necessary for the test (for example, 500 to 2000 ml) from a resin introduction path 3 and a sulfuric acid introduction path. 4, an amount of sulfuric acid solution necessary to make the sulfate ion composition of the anion exchange resin 40% or more is introduced, or an eluent such as ammonia-containing water is supplied from the eluent introduction path 5 to an amount required for the test (for example, 2 ８8 liters), and is configured to be brought into contact by being stirred by the stirrer 6. And on top contact eluent passage 8 for taking out the intracisternal solution 7 as eluent, the discharge portion 9 are in communication via valve 10 at the bottom.
[0024]
The eluent path 8 is branched via a pump P into branch paths 8a and 9b. A cation exchange column 11 and an anion exchange column 12 are provided in the branch channels 8a and 8b, respectively, and are filled with a cation exchange resin 11a and an anion exchange resin 12a different from the resin to be tested, respectively. The outflow water channels 13 and 14 communicate with each other, and conductivity meters S ₁ and S ₂ are provided, respectively. The measurement signals of the conductivity meters S ₁ and S ₂ are connected to be input to the arithmetic unit 15.
[0025]
Arithmetic unit 15 calculates the concentration of sulfate ion in the eluent from the measured value of the conductivity meter S _1, calculates the sulfate ion composition of the sample resin from this value, also sodium from the measured value of the conductivity meter S ₂ ions It is configured to calculate the concentration and calculate the sodium ion composition of the sample resin from the calculated value. When using the ion concentration meter instead of the conductivity meter S ₂ are sodium ion concentration directly is detected.
[0026]
A method for measuring the ion composition of the ion exchange resin including the reverse regeneration resin by the above-described apparatus will be described. First, the sample resin 2 is introduced into the elution tank 1 from the resin introduction passage 3, and the accompanying water is discharged from the discharge passage 9 through the valve 9. Use 10 to drain and drain. Then, a certain amount of sulfuric acid solution is introduced from the sulfuric acid introduction path 4 and stirred by the stirrer 6 and brought into contact with the resin for a predetermined time, usually 5 to 10 minutes, until the equilibrium is reached. To After the contact, the valve 10 is opened and the liquid in the tank is discharged from the discharge passage 9.
[0027]
Next, a certain amount of ammonia-containing water is introduced as an eluent from the eluent introduction path 5, and the mixture is stirred by the stirrer 6 and brought into contact for 5 to 10 minutes as a time until equilibrium is reached. At this time, by contact with the ammonia-containing water, cations such as sodium ions and anions such as sulfate ions which are exchange-adsorbed to the sample resin 2 are eluted. In this case, if the sample resin 2 contains a cation exchange resin, the cations adsorbed on the cation exchange resin are eluted by exchange adsorption of ammonium ions.
[0028]
When the pH of the two layers of the sample resin becomes high due to the contact with ammonium ions, the sulfate ions adsorbed on the anion exchange resin are eluted.
After the elapse of a predetermined time, when the stirring is stopped and the sample resin 2 is allowed to settle, the eluent is separated as an in-tank liquid 7 above the resin 2. 8 taken out and passed through the branch passage 8a to a cation exchange column 11. Since cations by cation exchange column 11, the cation exchange resin 11a is adsorbed and removed, it flows out effluent containing sulfate ion, the conductivity of the effluent containing sulfuric acid ions are measured by the conductivity meter S _1, computing device 15 Is input to
[0029]
When measuring the cation composition such as the sodium composition of the mixed resin, the cation is eluted by introducing ammonia-containing water without contacting the sulfuric acid solution, and the eluent is introduced into the anion exchange column. Since anion by anion exchange column 12, the anion exchange resin 12a is adsorbed and removed, runoff water flows containing cations such as sodium, the conductivity of the effluent water containing cations is detected by the conductivity meter S _2, computing device 15 is input.
[0030]
Calculating a sulfate ion concentration of the eluate from the measured value of the arithmetic unit 15 is input conductivity meter S ₁ by the equation including the following (1) or formula of the equivalent, equation (2) or from the value The sulfate ion composition adsorbed on the sample resin 2 is calculated by an equation including an equivalent equation . When measuring the cation composition calculation of cation composition is made from the measured values of S _2.
[0031]
Hereinafter, a method for calculating the sulfate ion composition will be described.
(1) SO ₄ concentration of sulfate ions (SO ₄₎ concentration eluent is calculated by the following equation.
[0032]
_{SO 4 = (1000 × S +} { [1000 × S] ² -4 × [2 × L1 + L2] ^{× L3 × 0.5 × 10 -14}} 1/2) / (2 × [2 × L1 + L2]) ...・ (1)
(1) where:
SO ₄ : SO ₄ concentration [eq / l]
S: conductivity [ms / m]
L1: Equivalent conductivity of H ion L2: Equivalent conductivity of SO ₄ ion L3: Equivalent conductivity of OH ion
(2) Sulfate ion composition (R-SO ₄ %)
Formula for R-SO ₄ is as follows.
SO ₄ concentration of the eluent from the ion equilibrium of the ion exchange resin and the liquid [SO _4] = (1 / k2) × ([R-SO _4%) / (R-OH]) × [NH _4] ...・ ・ (2)
(2) where
[SO ₄ ]: Eluent SO ₄ concentration (eq / l)
k2: OH and SO ₄ in the selected coefficients [R-SO _4%]: SO ₄ ions percentage adsorbed on the resin [R-OH]: OH ions percentage adsorbed on the resin [NH _4]: inflow NH ₄ concentration (eq / l)
[0034]
Since R-OH + R-SO ₄ = 1 (100%),
[SO ₄ ] = (1 / k2) × ([R-SO ₄ %] / [1- [R-SO ₄ %]]) × [NH ₄ ] (3)
[R-SO ₄ %] = k2 × [SO ₄ ] / ([NH ₄ ] + k2 × [SO ₄ ]) ... (4)
Therefore, [R-SO ₄ %] can be calculated from the [SO ₄ ] concentration of the eluate calculated in (1).
However, since the calculated here the R-SO _4% is a value associated with the addition of SO _4, if subtracted R-SO _4% added here, R-SO _4% of the sample resin can be calculated.
[0035]
【Example】
In FIG. 1, an anion exchange resin having an exchange capacity of 1.2 eg / l was introduced into a 1 liter elution tank 1 as a sample resin. Then, in order to inject 0.48 eg / l of sulfuric acid corresponding to 40% of the exchange capacity of the resin, 480 ml of a 1N aqueous sulfuric acid solution was introduced, and the mixture was brought into contact with the mixture by stirring for 1 to 10 minutes to adjust the sulfuric acid composition to 40% or more. After stirring, water was discharged.
[0036]
Next, a 10 g / l aqueous ammonia solution was introduced into the elution tank and stirred for 1 to 10 minutes to elute sulfate ions. After the completion of the stirring, the resin was allowed to stand for 1 to 3 minutes to settle the resin, the solution in the tank was passed through a cation exchange column as an eluent, and the conductivity was measured by a conductivity meter.
[0037]
The sulfuric acid concentration in the eluate was calculated from the measured conductivity by the above formula, and the sulfate ion composition of the sample resin was calculated from the value by the formula. Leak SO ₄ concentration (mg / l) and resin sulfate ion composition _R-SO 4 obtained by subtracting the SO ₄ concentration injected from SO ₄ concentration in the eluent relationship (%) shown in FIG.
[0038]
In the above operation, since equilibrium is reached in a short time in the elution tank, the sulfate ion composition of the sample resin 2 can be accurately measured in a short time at low cost. Can be determined. For this reason, when a regeneration failure occurs, the regeneration operation can be performed again before the actual water flow, whereby the completely regenerated resin without the regeneration failure can be subjected to the condensate treatment, and the treated water deteriorates. Can be prevented in advance.
[0039]
【The invention's effect】
According to the present invention, after the sample resin is brought into contact with the sulfate ion in the elution tank and then brought into contact with the eluent, even when the sulfate ion composition of the sample resin is low, the sulfate ion adsorbed on the sample resin is eluted. Thus, the sulfate ion concentration of the eluate can be measured, whereby the sulfate ion composition of an anion exchange resin such as sulfate ions can be measured quickly, accurately and at low cost with a simple apparatus and method.
[Brief description of the drawings]
FIG. 1 is a system diagram of an apparatus for measuring an ion composition of an ion exchange resin according to an embodiment.
FIG. 2 is a graph showing the relationship between the concentration of leak SO ₄ and R-SO ₄ in an example.
FIG. 3 is a graph showing the relationship between the concentration of leaked SO ₄ and R-SO ₄ .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Elution tank 2 Sample resin 3 Resin introduction path 4 Sulfuric acid introduction path 5 Eluent introduction path 6 Stirrer 7 Liquid in tank 8 Eluent paths 8 a and 8 b Separation path 9 Discharge path 10 Valve 11 Cation exchange column 12 Anion exchange column 11 a Cation exchange Resin 12a Anion exchange resin 15 Arithmetic unit P Pump S ₁ , S ₂ Conductivity meter

Claims (1)

An elution tank for introducing the sample resin, bringing the sulfate ion composition into contact with sulfate ion in an amount of 40% or more, and further bringing the sample resin into contact with an eluent to elute ions adsorbed on the resin;
A sulfuric acid supply path for supplying sulfuric acid to the elution tank,
An eluent supply path for supplying an eluent to the elution tank,
A cation exchange column for receiving a part of the eluent in the elution tank and performing cation exchange,
A conductivity meter for measuring the conductivity of the effluent of the cation exchange column,
The sulfate ion concentration in the eluent is calculated from the measured value of the conductivity meter by the following formula (1) or a formula including the equivalent formula, and the formula (2) or a formula including the equivalent formula is calculated from the calculation result. Calculates the sulfate ion composition in the sample resin by subtracting the amount of sulfate ions first introduced into the elution tank and adsorbed on the anion exchange resin, thereby calculating the sulfate ion composition in the sample resin before sulfate ion adsorption. An ion exchange resin ion composition measuring device, comprising: an arithmetic device.
_{SO 4 = (1000 × S +} { [1000 × S] ² -4 × [2 × L1 + L2] ^{× L3 × 0.5 × 10 -14}} 1/2) / (2 × [2 × L1 + L2]) ...・ (1)
(1) where:
SO ₄ : SO ₄ concentration [eq / l]
S: conductivity [ms / m]
L1: H ion equivalent conductivity
L2: equivalent conductivity of SO ₄ ion
L3: Equivalent conductivity of OH ion
[SO ₄ ] = (1 / k2) × ([R-SO ₄ %] / [R-OH]) × [NH ₄ ] (2)
(2) where
[SO ₄ ]: Eluent SO ₄ concentration (eq / l)
k2 : Selection coefficient of OH and SO ₄
[R-SO ₄ %]: ratio of SO ₄ ions adsorbed on the resin
[R-OH]: ratio of OH ions adsorbed on the resin
[NH ₄ ]: concentration of NH ₄ inflow (eq / l)
R-OH + R-SO ₄ = 1 (100%)

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