JP2002143694A - Method for predicting life of ion exchange resin and prediction system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a system such that the life of an ion exchange resin can be properly predicted while taking not only the ion load by the fluid to be treated but the pyrolysis into consideration when the ion exchange resin is used for the system applied with heat and requiring the ion exchange treatment at high temperature. SOLUTION: The method for predicting the life of an ion exchange resin and the prediction system have the following features. The relation between the temperature and the period until the ion exchange capacity of the ion exchange resin reaches to a specified low level in the process of treating the objective fluid under the temperature in the system applied with heat is preliminarily stored for each temperature. The decreased ion exchange capacity under the current conditions is calculated based on the stored relation formula under the current temperature while the decreasing amount is accumulated. When the accumulated decreasing amount reaches a preliminarily determined level, the ion exchange resin is judged at the end of its service life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and a system for predicting the life of an ion exchange resin, and more particularly to a method and a system for predicting the life when a heat load is applied to the ion exchange resin.

[0002]

2. Description of the Related Art In the case of performing a desalination treatment using an ion-exchange resin and operating near normal temperature, if the concentration of impurities in the ion-exchanged fluid can be grasped, the remaining operable time can be estimated. It is possible. That is, if the operation is at around normal temperature, the life of the ion exchange resin used can be roughly predicted from the calculation of the ion exchange capacity / impurity load. From this calculation, it is possible to construct a system that senses that the remaining amount of the ion exchange capacity has decreased during operation and notifies the user before the life of the ion exchange resin reaches the end of its life using current technology.

[0003]

However, when an ion-exchange resin is used in a system subjected to a heat load, the life of the ion-exchange resin cannot often be predicted by a simple calculation as described above. In particular, when a non-heat-resistant standard ion exchange resin, particularly an anion exchange resin which is easily affected by heat, is used at a high temperature, the life of the ion exchange resin cannot be predicted by the above-described method.

[0004] Anion exchange resins have the property of being easily affected by heat, and generally have a strong basic cation exchange resin in comparison with the operation temperature of about 100 ° C. In the anion exchange resin, the regeneration type (hydroxide ion type) is limited to around 50 ° C. When continuously removing anions under such temperature conditions exceeding the operating temperature, it is necessary to consider that the removal of the exchange group due to Hoffman decomposition due to heat, etc., will be a factor in reducing the processing time until ion breakthrough. There is. In other words, the Hoffman decomposition causes a phenomenon in which the exchange group itself disappears and a phenomenon in which, for example, the quaternary ammonium base becomes a lower base (becomes weakly basic), thereby decomposing the neutral salt such as carbonate and silica. Is gone,
These neutral salts cannot be removed by ion exchange treatment. Therefore, in the process at such a high temperature, since the ion exchange capacity decreases more rapidly than the operation at around normal temperature, the ion exchange capacity is divided by the ion load of the fluid to be treated as described above. There was a problem that the life could not be calculated by simple calculation.

Therefore, an object of the present invention is to apply a heat load,
When using ion-exchange resin in a system that requires ion-exchange treatment at high temperature, consider the thermal decomposition reaction in addition to the ion load of the fluid to be treated. It is an object of the present invention to provide a method and system capable of appropriately estimating the lifetime and appropriately predicting the lifetime.

[0006]

In order to solve the above-mentioned problems, a method for estimating the life of an ion-exchange resin according to the present invention is a method for estimating the life of an ion-exchange resin used in a system under heat load. The relationship between the temperature in the system or a system equivalent to the system, and the time until the ion exchange capacity of the ion exchange resin reaches a certain degree of reduction when the fluid to be treated is treated at the temperature, It is obtained and stored in advance for each of a plurality of temperatures, detects the temperature applied to the ion exchange resin currently used, and calculates the ion exchange capacity of the ion exchange capacity under the condition at that time based on the stored relationship from the detected temperature. Calculating a reduction amount, accumulating the calculated reduction amount of the ion exchange capacity, and determining that the ion exchange resin has reached the end of its life when the accumulated reduction amount reaches a predetermined value. Or It made.

[0007] The system for predicting the life of an ion-exchange resin according to the present invention is a system for predicting the life of an ion-exchange resin used in a system to which a heat load is applied. In a system equivalent to the system
Means for storing, for each of a plurality of temperatures, the relationship between the temperature and the time until the ion exchange capacity of the ion exchange resin reaches a certain degree of reduction when the fluid to be treated is processed at the temperature, Means for detecting a temperature applied to the ion exchange resin, and calculating a reduction amount of the ion exchange capacity under the condition at that time based on the relationship stored in the storage means from the temperature detected by the detection means. It has an ion exchange capacity reduction amount calculating / judging means for accumulating the reduced amount of the ion exchange capacity, and determining that the ion exchange resin has reached the end of its life when the accumulated reduction amount reaches a predetermined value. It consists of the features.

In this ion exchange resin life prediction system, it is preferable that the above-mentioned relationship is stored in the storage means for a plurality of types of ion exchange resins. This makes it possible to easily and accurately predict the lifetime according to the ion exchange resin used at that time.

The means for calculating / determining the ion exchange capacity reduction amount can be constituted by a microcomputer, and the means can be connected to an alarm output means. The alarm may be a simple display or an alarm that actually issues an alarm or the like. As a result, the user can reliably recognize the life end time when the life is reached or in advance.

In the method and system for predicting the life of an ion exchange resin according to the present invention, the characteristics of reducing the ion exchange capacity of the ion exchange resin in the system when a heat load is applied are grasped and stored in advance. And
In the actual operation, the temperature is detected every moment, the amount of reduction in the ion exchange capacity at the detected temperature is obtained from the above characteristics, and the obtained amount of reduction is accumulated with time. Therefore, the accumulated reduction amount of the ion exchange capacity is calculated as a value in consideration of the thermal decomposition characteristics due to the heat load, in addition to the ion load amount of the fluid to be treated in the system, This is grasped as a more realistic reduction amount of the ion exchange capacity corresponding to the temperature history. As a result, the service life of the ion-exchange resin when a heat load is applied, which could not be predicted conventionally, can be roughly, but roughly, predicted.

[0011]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a system for estimating the life of an ion exchange resin according to one embodiment of the present invention, in which a high-temperature device, for example, a high-temperature heat engine is cooled with cooling water, and the ion-exchange resin is circulated in the cooling water circulation system. The example which arrange | positioned is shown. In FIG. 1, reference numeral 1 denotes the entire system for predicting the life of the ion exchange resin, and reference numeral 2 denotes a heat exchange unit for cooling a high-temperature device, for example, a high-temperature heat engine. Cooling water as a fluid to be processed is circulated through the heat exchange section 2 in the circulation line 3 by the circulation pump 4.

A cooling unit 5 for cooling the circulating cooling water is provided in the circulating line 3. The cooling water is configured as a system in which the temperature of the cooling water may be considerably higher than normal temperature. The circulation line 3 is provided with an ion exchanger 6 filled with an ion exchange resin in order to remove impurities in the cooling water by an ion exchange treatment. In this cooling water circulation system, the flow rate of the cooling water circulated by the circulation pump 4 is set to a constant flow rate, and the circulation system is configured as a closed system. The ion load on the substrate is substantially constant. That is, the only factor that changes the degree of deterioration of the ion exchange resin charged in the ion exchanger 6 is substantially only the temperature.

Before and after the ion exchanger 6, temperature sensors 7a and 7b (TI1 and TI2) are provided as temperature detecting means for detecting the temperature of the cooling water treated by the ion exchange resin. As the temperature of the cooling water,
Average value of the detection values of both temperature sensors 7a and 7b (T =
0.5 (T1 + T2)). However, in this embodiment, two temperature sensors 7a,
Although 7b is provided, only one may be provided, preferably one at the inlet side of the ion exchanger 6.

Signals of the temperature of the cooling water (T: average value on the inlet and outlet sides) detected by the temperature sensors 7a and 7b are sent to a microcomputer 8 as a means for calculating and judging the ion exchange capacity reduction amount. In this embodiment, an alarm output means 9 is connected to the microcomputer 8 so that an appropriate alarm signal such as a display or an alarm (alarm sound or alarm lamp) can be output based on a command from the microcomputer 8. Has become.

The microcomputer 8 includes a storage means for storing the ion exchange capacity reduction characteristics of the ion exchange resin, which is grasped in advance, as described below, and a temperature sensor 7a,
7b, based on the signal of the temperature at that time, collating with the characteristic, calculating the ion exchange capacity reduction amount of the ion exchange resin at the temperature at that time, and calculating the calculated ion exchange capacity reduction amount with time. A judgment means for judging whether or not the accumulated ion exchange capacity reduction amount has reached a predetermined value is incorporated. In order to calculate the ion exchange capacity reduction amount of the ion exchange resin at the temperature at that time, an element of the duration of the state is necessary, so the microcomputer 8 counts the reference measurement time for the above calculation every moment. A clock counter is also included.

The life of the ion exchange resin in the above system according to the present embodiment is determined as follows. The characteristic of reducing the ion exchange capacity at each temperature of the ion exchange resin used is grasped in advance. The reduction characteristic is obtained in advance, for example, as a characteristic as shown in FIG. That is, when the fluid is continuously used at each of the temperatures T ₁ , T ₂ , T _3, ..., The fluid to be treated in the system (constant ion load characteristics, constant flow rate) or the ion load characteristics equivalent to the system and For systems with flow characteristics, the ion exchange capacity is
It decreases rapidly at a relatively early stage, and gradually decreases thereafter. This characteristic is grasped for each temperature. A large number of such ion-exchange capacity reduction characteristics have been reported to date by each technician and researcher, and in particular, the time-dependent ion-exchange capacity of a typical strongly basic anion exchange resin at each temperature. The change characteristics are shown.

In the characteristics shown in FIG. 2, if the standard for calculating the life of the ion exchange resin is, for example, the time for which the ion exchange capacity is halved (for example, the number of days for halving),
The half-life is the initial value of ion exchange capacity (100%)
As a point of intersection between the line of the ion exchange capacity of 50% and the characteristic line for each temperature. When the temperatures T ₁ , T ₂ , T ₃ ... And the half-life times t ₁ , t ₂ , t _3. Thereby, the reduction rate of the ion exchange capacity can be expressed as a function of the temperature.

For example, in the case of a strongly basic anion exchange resin, it is assumed that all the thermal degradation reactions are caused by Hoffman decomposition, and that the degradation rate is proportional to the production rate of trimethylamine from a quaternary ammonium base. . Then, as shown in FIG. 3, the reciprocal of the absolute temperature (1/1)
T [K ^-1 ]), the natural logarithm (ln (1 / HLD)) of the reciprocal of the time until the initial ion exchange capacity decreases to a fixed rate (for example, 50% as described above). , H .;
L. D: half-life of the ion exchange capacity), a straight line as shown in FIG. 3 is obtained, which can be regarded as a primary reaction.

A characteristic representing the relationship between the temperature and the ion exchange capacity reduction amount as shown in FIG. 3 is stored in the storage means of the microcomputer 8 in advance. This storage may be performed for a plurality of types of ion exchange resins, and the characteristics of the ion exchange resin used at that time may be read.

When the ion exchange process is actually performed, the temperature T detected by the temperature sensors 7a and 7b is input to the microcomputer 8, and based on the input signal, the microcomputer 8 having a timer function (time measuring function) is provided. Thus, the amount of reduction of the ion exchange capacity of the used ion exchange resin after a certain reference time at the temperature at that time is calculated substantially in real time. The temperature signal is input every time the reference time elapses by the clock counter function, and the above-mentioned ion exchange capacity reduction amount is accumulated. If the reference time is set to be relatively short, even if there is a temperature change in the fluid to be processed, the cumulative calculation can be performed by accurately following the change.

By subtracting the successively reduced amount of the ion exchange capacity from the initial value of the ion exchange capacity, the ion exchange capacity remaining at that time adds the temperature effect to the ion load. Calculated as a result, that is, the current actual state or a state very close to the current state. Therefore, from the accumulated reduction amount of the ion exchange capacity, whether or not the ion exchange resin has reached the exchange time, that is, whether or not the life has reached, can be accurately and accurately determined with a high accuracy. . For example, when the half time of the ion exchange capacity is set as the life, the reaching of the half time is accurately determined, or the timing of reaching the half time is accurately determined in advance. However,
The setting of the life reaching time is not limited to the time when the ion exchange capacity is halved, and may be arbitrarily determined according to the conditions of the system and the type of resin used.

In particular, as described above, if the characteristics as shown in FIG. 3 (in some cases, the characteristics as shown in FIG. 2) are stored in the microcomputer 8 as libraries for a plurality of types of ion exchange resins, As shown in the flow of data processing in FIG. 4, the input setting unit 11 inputs the unique name of the resin used at that time, and determines the replacement time when the amount of reduction in the ion exchange capacity is to be replaced. The notification allows the arithmetic processing unit 12 to search the data library 13 for the corresponding data characteristic, set a calculation formula based on the data characteristic, and perform the above-described sequential calculation.

As described above, the relationship between the temperature and the ion exchange capacity in consideration of the heat load is grasped in advance, and based on the relationship, the cumulative reduction amount of the ion exchange capacity is calculated while detecting the temperature history actually applied. By doing so, it becomes possible to predict the life of the ion exchange resin almost accurately even when thermal decomposition occurs.

[0024]

As described above, according to the method and system for predicting the life of an ion-exchange resin of the present invention, the life of an ion-exchange resin under a heat load, which could not be predicted conventionally, is actually reduced. Based on the added temperature history, it is possible to make an almost accurate prediction. Therefore, it is possible to replace the ion exchange resin at an appropriate time, and it is possible to prevent the occurrence of a trouble due to thermal deterioration of the ion exchange resin.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ion exchange resin life prediction system according to one embodiment of the present invention.

FIG. 2 is a graph showing a reduction characteristic of an ion exchange capacity at each temperature.

FIG. 3 is a characteristic diagram showing the relationship between the reciprocal of the absolute temperature and the logarithm of the reciprocal of the half-life of the ion exchange capacity.

FIG. 4 is a conceptual diagram illustrating an example of data processing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Expected life system of ion exchange resin 2 Heat exchange part 3 Circulation line 4 Circulation pump 5 Cooler 6 Ion exchanger 7a, 7b Temperature sensor 8 Microcomputer 9 Alarm output means 11 Input setting part 12 Arithmetic processing part 13 Data library

Claims (4)

[Claims] 1. A method for predicting the life of an ion-exchange resin used in a system to which a heat load is applied, wherein a temperature of the system or a system equivalent to the system and a fluid to be treated are treated at the temperature. In this case, the relationship with the time until the ion exchange capacity of the ion exchange resin reaches a certain degree of reduction is obtained and stored in advance for each of a plurality of temperatures, and the temperature applied to the ion exchange resin currently used is stored. Based on the stored temperature, the amount of reduction of the ion exchange capacity under the current condition is calculated based on the detected temperature, and the calculated amount of reduction of the ion exchange capacity is accumulated. A method for predicting the life of an ion-exchange resin, comprising determining that the life of the ion-exchange resin has reached a predetermined value. 2. A system for predicting the life of an ion-exchange resin used in a system subjected to a heat load, wherein the temperature and the temperature in the system or a system equivalent to the system are determined in advance. The means for storing the relationship between the time required for the ion exchange capacity of the ion exchange resin to reach a certain degree of reduction when the fluid to be treated is processed for each of a plurality of temperatures and the time required for the ion exchange resin currently used Means for detecting the temperature, and calculating the amount of reduction of the ion exchange capacity under the condition at that time based on the relationship stored in the storage means from the temperature detected by the detection means, It is characterized by having an ion exchange capacity reduction amount calculating / judging means for accumulating the reduction amount, and determining that the ion exchange resin has reached the end of its life when the accumulated reduction amount reaches a predetermined value. , Ion exchange resin life prediction system. 3. The system for predicting the life of an ion exchange resin according to claim 2, wherein said relationship is stored in said storage means for a plurality of types of ion exchange resins. 4. An alarm output means is connected to said ion exchange capacity reduction amount calculation / judgment means.
Life prediction system for ion exchange resins.