JP2002174402A - Method and system for treating boiler water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and system for treating boiler water by which the management of various kinds of boilers can be performed easily, quickly, and highly safely by coping with the variation, etc., of the flow rate or quality of the feed water to the boilers. SOLUTION: The boiler water treating system is provided with a chemical adding means which adds a boiler water treating chemical to the boiler water of a soft water boiler or pure water boiler, a blow water quantity control means which controls the quantity of blow water discharged from the boiler, and an ion concentration measuring section which measures the concentration of a cationic component or anionic component contained in the boiler water. The system is also provided with a control section which controls the chemical adding means and/or blow water quantity control means based on the measured results of the ion concentration measuring section. The ion concentration measuring section is constituted of ion selective electrodes which measure the concentration in the boiler water of a cationic component or anionic component which is not contained substantially in soft water or pure water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating boiler water and a system for treating boiler water, and more particularly, to preventing problems such as corrosion, scale formation or selective carryover of silica in a boiler. The present invention relates to a boiler water treatment method for adding a boiler water treatment chemical while controlling the concentration of the boiler water treatment chemical added and the boiler water concentration, and a boiler water treatment system applied to this method.

[0002]

2. Description of the Related Art Conventionally, a raw water boiler using raw water such as industrial water and well water as it is, and a soft water boiler or pure water boiler using soft water or pure water obtained by treating the raw water are generally used. Used in Usually, the boiler controls the temperature of the boiler water under pressure to 1
It is operated at a temperature between 10 ° C and the critical temperature.

In a soft water boiler, so-called soft water from which most of the hardness components have been removed by soft water treatment using an ion exchange resin or the like is used as boiler water. Therefore, even when highly concentrated water is used, that is, the amount of blow water is relatively small. Even in this case, there is little occurrence of scale. However, since the anion components other than the hardness component, especially chloride ions, sulfate ions, etc., are not removed by the above-described soft water treatment, due to these anion components and oxygen present in the soft water,
Corrosion of iron-based metal in the boiler system easily causes pitting (pitting), which leads to serious obstacles.

Therefore, in a soft water boiler, conventionally, a deaerator using a deaerator or a deoxidizer by adding a deoxidizer such as a sulfite or hydrazine is used in combination with a soft water treatment. Phosphates and, if necessary, an alkali agent are further added to water to adjust the pH to 10 to 12.
By adjusting to, corrosion of iron-based metal in the boiler system,
In particular, a method for preventing pitting has been adopted.

On the other hand, in a pure water boiler, pure water having an electric conductivity of 0.1 mS / m or less, in which ionic components such as alkali metal ions, alkaline earth metal ions, sulfate ions and chloride ions are substantially removed, is used. Although ion-exchanged water is used as boiler water, pure water boilers also use iron-based metals in the boiler system due to carbonate ions and dissolved oxygen inevitably present in the boiler water due to the dissolution of carbon dioxide gas in the air. Are easily corroded, and pitting is likely to occur as in the case of a soft water boiler.

For this reason, in a pure water boiler, pure water is passed through a deaerator and an oxygen scavenger such as sulfite or hydrazine is added to perform a deoxygenation treatment. Further, morpholine, cyclohexylamine, dimethylmethanolamine, etc. Is added as a carbonic acid scavenger, and further, a phosphate-based anticorrosive is added to prevent corrosion of iron-based metals in the boiler system, particularly pitting corrosion.

[0007] Japanese Patent Application Laid-Open No. 8-105605 discloses a system for performing chemical injection for boiler water supply. Here, an electric conductivity meter for detecting the electric conductivity of the boiler feedwater is provided in the middle of the boiler water supply system, the detected electric conductivity is input to the chemical injection control device, and the calculation previously input to the chemical injection control device is performed. A chemical injection system for a boiler using electric conductivity in feed water has been proposed, which can calculate a chemical injection rate based on an equation and constantly perform an optimum chemical injection based on the calculated chemical injection rate. .

Japanese Unexamined Patent Publication (Kokai) No. 6-343949 discloses that an additive added to a raw water stream such as a boiler stream and / or a boiler system has a predetermined amount of an inert tracer, for example, one or two kinds. Addition of more than one fluorescent species and monitoring and measuring the fluorescence from the inert tracer at both the sampling and monitoring positions set upstream and downstream of the point where the additive is consumed, resulting in an additive consumption rate Is calculated, and the additive supply rate is arbitrarily adjusted according to the consumption amount.

Furthermore, Japanese Patent Application Laid-Open No. 51-11388 discloses a method for controlling the concentration of an added drug in water. In this method, a water-soluble salt of lithium is added to water as a tracer, and the concentration of the drug added to the water is controlled by measuring the concentration of lithium by an atomic absorption method.

[0010]

In a boiler water to which a boiler water treatment agent such as an oxygen scavenger, an alkali agent and an anticorrosive agent added for the above purpose is added, the concentration of the agent is as follows: Physical factors, such as the amount of boiler water treatment chemicals added, the amount of boiler water treatment chemicals mainly contained in blow water, the transfer of boiler water treatment chemicals to steam in the boiler water system, and thermal decomposition.・ Affected by the amount of drug that changes due to chemical effects.

[0011] The treatment chemicals in the boiler feedwater or boiler water are always affected by the above-mentioned conditions, and therefore, in order to sufficiently perform the boiler water treatment, it is necessary to constantly manage both of them. Therefore, conventionally, in a soft water boiler, in accordance with JIS B8223 and the like, the concentration of chlorine ions in the feed water and the boiler water is measured to calculate the concentration of the boiler water. The concentration of the residual chemical was measured, and the amount of the chemical treated in the boiler water was controlled in consideration of the result and the amount of the discharged chemical contained in the blow water.

In addition, the above is generated independently of the above, and the concentration control of the boiler water treatment chemical affected by the above is difficult to directly measure the concentration. By managing, a person skilled in the art can perform management to some extent empirically. However, the above and management required considerable skill.

On the other hand, drain recovery water whose flow rate changes as needed flows into the boiler feed water, and the chloride ion concentration also fluctuates with the flow. Therefore, the above-described measurement results of the chloride ion concentration in the feed water and the boiler water indicate that: , The concentration of boiler water could not be calculated accurately. Also, JIS
The above-mentioned method according to B8223 or the like requires two types of measurement, i.e., measurement of chloride ion concentration and measurement of residual drug concentration involving complicated operations, and furthermore, a pure water boiler in which chlorine ions do not exist in boiler water. There was a problem that it could not be applied.

The deoxidizer is usually used for chemically removing dissolved oxygen remaining in the water supplied from the deaerator, but is used when the deaerator is not provided. When the amount of the oxygen scavenger becomes considerable and an accompanying obstacle, for example, a large amount of sodium sulfite is added, the electric conductivity increases and an obstacle such as carryover occurs. Further, it has been difficult to constantly control and add the required amount of the oxygen scavenger and to control the discharge amount of the blow water.

[0015] In the interlocking chemical injection system of a boiler disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-105605, the above two types of operations are required in order to always perform the optimum chemical injection. It is considered that automation of boiler management involves difficulties in responding to changes in electrical conductivity due to fluctuations in water quality and managing the concentration of boiler water. Also,
In the above-mentioned JP-A-6-343949, it is essential to add an inert tracer such as a fluorescent species. However, since the fluorescent species has low thermal stability, it can be applied to a low-pressure boiler.
There was a problem that it could not be applied to high pressure boilers. Further, in the method described in JP-A-51-111388, a water-soluble salt of lithium is added to water as a tracer. However, since the method is a method for quantitatively analyzing lithium by an atomic absorption method, the operation is complicated. However, it required large-scale equipment, and was not suitable for implementation on site.

The present invention has been made in view of the above-described problems, and can respond to changes in the flow rate and water quality of boiler feedwater in various types of boilers at any time, making the boiler management simple and quick. And a highly safe boiler water treatment method and a boiler water treatment system.

[0017]

According to the present invention, when a boiler water treatment is performed by adding a boiler water treatment chemical to a boiler water of a soft water boiler or a pure water boiler, the soft water or the pure water substantially contains the same. A boiler water characterized by adding a cation or anion component not contained as a boiler water treatment chemical or separately to boiler water, measuring the concentration in the boiler water with an ion electrode, and managing the boiler water based on the result. A processing method is provided.

That is, the inventors of the present invention have conducted intensive studies in view of the above problems, and have found that a cation or anion component substantially not contained in soft water or pure water is used as a boiler water treatment agent or separately. By adding it to boiler water and measuring the concentration in the boiler water with an ion electrode, the chlorine ion concentration in the boiler water system and the concentration of the boiler water treatment chemical remaining in the boiler water (hereinafter referred to as “residual chemical concentration”) "), And a boiler water treatment method and a boiler water treatment system that can be applied to a pure water boiler in which chlorine ions do not exist in the boiler water have been completed.

That is, a cation or anion component is separately added to water or boiler water as a boiler water treatment agent, or the cation or anion component is correlated with the concentration of the boiler water treatment agent in the boiler water. By measuring the concentration at
Since the concentration of the boiler water treatment chemical in the boiler water can be ascertained, the concentration of the boiler water and / or
Alternatively, the boiler water treatment can be easily, quickly and accurately managed by controlling the amount of the boiler water treatment chemical added. Further, in the treatment method of the present invention, the use of an organic solvent, which has been conventionally performed when measuring the residual drug concentration, becomes unnecessary, so that the on-site safety can be improved.

The boiler water treatment chemical in the present invention is:
It is added to the water supplied to the boiler or to the boiler water supplied to the boiler, changes harmful impurities into harmless substances in the boiler, and adjusts the boiler water to a state suitable for preventing corrosion in the boiler. Means an agent to maintain. As chemicals constituting such boiler water treatment chemicals, phosphates, nitrites, carboxylates, cobalt salts, molybdates, tungsten salts, diethylenetriamine for suppressing corrosion of iron-based metals in contact with water. , Sodium hydroxide, potassium hydroxide, lithium hydroxide, polymeric phosphates, polymeric dispersants, anticorrosives, dispersants, reaction accelerators such as starch and amino acid derivatives, sulfites, hydrazine, sugars, aminopyrrolidine, tannin , Gallic acid, diethylhydroxylamine, methylethylketoxime, succinate, tannate, gluconate, ascorbic acid, erythorbic acid, carbohydrazide and other oxygen absorbers, morpholine, cyclohexylamine, dimethylmethanolamine, monoethanolamine, 2-amino-2-methyl-1-pro Nord, diethanolamine, ammonia, octadecylamine, and the like carbonate scavenger such as methoxypropyl amine. The boiler water treatment chemicals used in the method of the present invention are not limited to these chemicals, and those used in ordinary boiler water systems can be used as appropriate. In particular, one-pack type boiler water treatment chemical "Miracle Shan", which does not require the addition of a deoxidizer such as hydrazine, manufactured by Katayama Chemical Industry Laboratory Co., Ltd. [Miracle Shan is a product of Katayama Chemical Industry Laboratory Co., Ltd. Registered trademark] is preferred.

The "cation or anion component substantially not contained in soft water or pure water" in the present invention means that it cannot be present in boiler water except for being added to feed water or boiler water, or even if present. It is an extremely small amount of component compared to the amount added. Further, in the present invention, the cation or anion component measured by the ion electrode,
Also included are those generated or formed as boiler water treatment chemicals or by separate addition. In addition, "substantially not contained" means that even if it is present in a very small amount in boiler water, it is contained at such a concentration that does not affect the measurement result by the ion electrode.

The cation component or anion component is not particularly limited as long as it can be measured by an ion electrode. However, from the viewpoint of the boiler water treatment effect and the operability of the measurement by the ion electrode, monovalent or divalent components are used. Cations or anions are preferred. As the cation component,
Lithium ion, sodium ion, potassium ion,
Ammonium ions, magnesium ions, calcium ions, strontium ions and the like, in particular,
Lithium ion is preferred in terms of corrosion prevention and measurement accuracy with an ion electrode. Examples of the anion component include a carboxylate ion, a chloride ion, a bromine ion, and an iodine ion. In particular, a carboxylate ion is preferable in terms of corrosion prevention, scale prevention, and measurement accuracy with an ion electrode. In addition, polyvalent ions such as molybdate ion, phosphate ion and citrate ion are exemplified.

The substance which generates the cation or anion in the boiler water as described above is preferably a component which is harmless and does not pollute the environment without at least inhibiting the boiler water treatment effect in the boiler. The cation and / or anion components suitable for the properties of the water can be selected. Further, it is preferable that the cation or anion component forms a component which substantially acts as a boiler water treatment agent, or acts as a substantial boiler water treatment agent.
Examples include lithium hydroxide and gluconic acid. Further, a compound which does not substantially act as a boiler water treatment agent, but can release the above cation or anion in water, which can be measured using an ion electrode, may be added together with or separately from the boiler water treatment agent. it can. Examples of such compounds include lithium chloride. The amount (concentration) of the substance that generates the cation or anion in the boiler water as described above is not particularly limited, and may be any concentration as long as it can be detected using an ion electrode.

As the ion electrode used in the method of the present invention, for example, a carboxylate ion electrode, a lithium ion electrode, a chlorine ion electrode or the like can be appropriately used according to the ion to be measured.

In the method of the present invention, since the concentration of the residual chemicals in the boiler water and the degree of concentration of the boiler water are simultaneously grasped, whether the increase or decrease in the concentration of the residual chemicals is due to the added amount of the chemicals for treating the boiler water is considered. It becomes clear whether it is due to the discharge amount of the treatment chemical, and the water treatment of the boiler water can be appropriately managed based on the result. Therefore, corrosion of the inside of the boiler and generation of scale due to overconcentration of sludge, insoluble components or chloride ions serving as corrosion factors can be suppressed, and failures and accidents of the superheater and turbine due to carryover can be prevented.

According to the present invention, there is provided a deoxygenating means for removing oxygen from the boiler water, the dissolved oxygen concentration in the boiler feedwater is measured by a dissolved oxygen concentration meter, and the driving of the deoxygenating means is controlled based on the result. Thereby, the oxygen in the boiler feedwater can be easily and accurately removed. If the pH of the blow water from the boiler is measured and the discharge amount of the blow water from the boiler is controlled based on the result, the discharge of the blow water is performed more accurately.

According to another aspect of the present invention, a chemical adding means for adding a boiler water treatment chemical to boiler water of a soft water boiler or a pure water boiler, and a blow water amount for controlling an amount of blow water discharged from the boiler A control unit, an ion concentration measuring unit for measuring the concentration of the cation component or the anion component in the boiler water, and a control unit for controlling the chemical adding unit and / or the blow water amount control unit based on the measurement result of the ion concentration measuring unit. A boiler water treatment system, wherein the ion concentration measurement unit comprises an ion electrode for measuring the concentration of the cation component or the anion component in boiler water that is not substantially contained in soft water or pure water. Provided.

[0028] The apparatus further comprises deoxygenating means for removing oxygen from the boiler water, and a dissolved oxygen concentration meter for measuring the dissolved oxygen concentration in the boiler feedwater, and the control unit controls the dissolved oxygen concentration measured by the dissolved oxygen concentration meter. By controlling the deoxidizing means based on the above, it is possible to easily and accurately remove oxygen in the boiler feedwater. As the deoxidizing means in the present invention, a deaerator provided in the boiler water supply system and / or
Alternatively, a deoxidizer added to the boiler water system by a chemical adding means may be used. The above-described oxygen absorber is added to the boiler water treatment chemical as a one-pack type boiler water treatment chemical added to the boiler water together with the boiler water treatment chemical or separately from the boiler water treatment chemical. You.
When using the one-pack type boiler water treatment chemical, the addition amount of the one-pack boiler water treatment chemical added to the boiler water from the chemical addition means is based on the dissolved oxygen concentration measured by a dissolved oxygen concentration meter. Can be controlled. When adding an oxygen absorber to boiler water separately from the boiler water treatment agent, the amount of the boiler water treatment agent is controlled based on the ion concentration measured by the ion electrode, and the amount of the oxygen absorber added is dissolved. The control can be performed based on the dissolved oxygen concentration measured by the oximeter.

As described above, examples of the oxygen scavenger include sulfites, hydrazine, hydrazine derivatives, reducing sugars such as glucose, tannins, and oxygen scavenging amines.

Since the dissolved oxygen concentration changes depending on the chemical added from the chemical adding means, in order to accurately measure the dissolved oxygen concentration in the boiler feed water, the dissolved oxygen meter is provided by the boiler feed water upstream of the chemical adding means. Is preferably measured. Further, it is preferable to measure the dissolved oxygen concentration in the blow water from the boiler. The control unit further includes a pH meter for measuring the pH of the blow water from the boiler,
By controlling the blow water amount control means based on the pH of the boiler water measured by the H meter, the pH of the boiler water is controlled.
It can be said that this is a preferable embodiment because the adjustment of the temperature can be accurately performed and the comprehensive boiler water treatment management can be performed.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of a boiler water treatment method and a boiler water treatment system of the present invention will be described, but the present invention is not limited by the embodiment.

Embodiment 1 FIG. 1 schematically shows a configuration of a boiler plant to which the boiler water treatment method of the present invention is applied. In FIG. 1, a boiler plant 10 includes a water supply tank 2 disposed upstream of a boiler 1 via a water supply pipe 20, a chemical tank 4 for adding a boiler water treatment chemical to the water supply, and a blow water pipe 30. A blow valve 3 (blow water amount control means) and a heat exchanger 5 disposed downstream of the boiler 1;
It mainly comprises a drain recovery pipe 40 in which steam supplied from the boiler 1 is drained and recovered in the water supply tank 2.

The water supply pipe 20 further includes a pump (not shown) for supplying water from the water supply tank 2 to the boiler 1.
An ion concentration measuring section 6 for measuring the concentration of the cation component and / or the anion component in the feed water, which is branched from between the chemical tank 4 and the boiler 1, is provided. The ion concentration measuring unit 6 is connected to a sampling port 8 for sampling, which has an electromagnetic on-off valve 8a. In addition, blow water pipe 30
Has an ion concentration measurement unit 7 for measuring the concentration of the cation component and / or the anion component in the blow water provided downstream of the heat exchanger 5.
Is connected to a sampling port 9 for sampling, which is provided in the blow water pipe 30 and has an electromagnetic on-off valve 9a. The ion concentration measuring units 6 and 7 are composed of ion electrodes 16 and 17 and potentiometers 18 and 19 connected to the respective ion electrodes 16 and 17. When the ion concentration measuring units 6 and 7 are connected to the sampling ports 8 and 9, the boiler water collected from the sampling ports 8 and 9 immerses the ion electrodes 16 and 17, and the boiler water is measured by potentiometers 18 and 19. The concentration of the treatment agent is measured.

An example of the boiler water treatment method of the present invention using the boiler plant 10 will be described with reference to FIG.
The boiler plant 10 used a high-pressure boiler and was operated under the conditions shown in Table 1.

[0035]

[Table 1]

As the boiler water treatment chemical supplied from the chemical tank 4, a one-pack type boiler water treatment chemical mainly composed of a carboxylic acid amine salt [trade name: Miracle Shan 508S]
A product obtained by compounding lithium hydroxide hydrate with Katayama Chemical Industry Laboratory Co., Ltd. [Miracle, Shan and Miracle Shan are registered trademarks of Katayama Chemical Industry Laboratory Co., Ltd.] was used.

Ion electrode 1 for monitoring water supply and blow water
6 and 17, lithium ion electrodes [integrated type
A portable pH meter [model HM-21P manufactured by Toa Denpa Kogyo KK] was prepared as the potentiometers 18 and 19 using Toa Denpa Kogyo KK. The lithium ion electrode conforms to the sodium electrode specified in JIS K0101.

Using the above-mentioned boiler water treatment chemicals, the concentration measurement of the boiler water treatment chemicals performed for the boiler plant 10 and the management of the amount of the boiler water treatment chemicals added and the concentration of the boiler water based on the measurement results. Is described below. The drug concentrations were 10 mg / L, 100 mg / L, 100
Each standard solution was prepared at a liquid temperature of 25 ° C. at 0 mg / L and 10,000 mg / L. When the potential of a standard solution having a drug concentration of 1000 mg / L was measured, the indicated potential was -176 mV. Drug concentration is 1
When the potential of each standard solution of 0 mg / L, 100 mg / L and 10000 mg / L was measured, the indicated potential was -294 m each.
V, -235 mV and -117 mV. Based on the above results, a calibration curve showing the correlation between the drug concentration and the electromotive force was created. The boiler water treatment chemical was added from the chemical tank 4 to the water in the water supply pipe 20 based on the set values in Table 1. After operating the boiler 1 for a predetermined time, feed water and blow water (boiler water) were sampled from sampling ports 8 and 9 for sampling. The potentials of the sampled feed water and blow water were measured at a liquid temperature of 25 ° C., and the drug concentration in the feed water and the drug concentration in the blow water were calculated based on the calibration curve. From the calculated drug concentration, a change in the residual drug concentration was confirmed, and it was found that this change was caused by the concentration of the boiler water being outside the set value. Therefore, the opening of the blow valve 3 is adjusted based on these calculation results,
Further, the change of the drug concentration in the boiler 1 was monitored for several days. The concentration of the chemical in the boiler 1 was adjusted to the set value of 1500 mg / L by controlling the addition amount of the chemical for treating the boiler water and the concentration of the boiler water while monitoring the above-mentioned concentration transition.

FIG. 2 shows a change in the concentration of the boiler water treatment chemical in the boiler 1 performed according to the above procedure. As shown in FIG. 2, it can be seen that the drug concentration in the boiler 1, which fluctuated greatly in the initial stage, approached the set value of 1500 mg / L in the final stage. As a reference measurement, a conventional flame photometric measurement of lithium in the boiler water treatment chemicals in Table 2 was performed using the same sample in parallel with the above operation (FIG. 2).示 す).

The correlation coefficient between the lithium measurement result by the conventional method using the flame photometry method and the measurement result using the lithium electrode of the present invention was 0.99, and the measurement of the lithium ion concentration using the lithium electrode was performed. The results turned out to be accurate.

Embodiment 2 FIG. 3 schematically shows a configuration of a boiler plant to which a boiler water treatment system of the present invention for automatically controlling boiler water treatment is applied. In FIG. 3, a boiler plant 50 includes a water supply tank 2 disposed upstream of the boiler 1 via a water supply pipe 20, a chemical tank 14 and a pump 12 for adding a boiler water treatment chemical to water supply, a blower, An electromagnetic blow valve 13 and a heat exchanger 5 disposed downstream of the boiler 1 via a water pipe 30; and a drain recovery pipe in which steam supplied from the boiler 1 is drained and recovered in the water supply tank 2. 40 mainly. In the chemical tank 14, the amount of the boiler water treatment chemical added to the water supply can be arbitrarily set by drive control of the pump 12. The blow valve 13 can arbitrarily set the discharge amount of blow water discharged through the blow water pipe 30 by adjusting the opening degree.

Further, a pump (not shown) for feeding water from the water supply tank 2 to the boiler 1 is provided in the water supply pipe 20.
An ion concentration measuring section 6 for measuring the concentration of the cation component and / or the anion component in the feed water, which is branched from between the chemical tank 14 and the boiler 1, is provided. The ion concentration measuring unit 6 is connected to a sampling port 8 for sampling, which has an electromagnetic on-off valve 8a. In addition, blow water pipe 30
Has an ion concentration measurement unit 7 for measuring the concentration of the cation component and / or the anion component in the blow water provided downstream of the heat exchanger 5.
Is connected to a sampling port 9 for sampling, which is provided in the blow water pipe 30 and has an electromagnetic on-off valve 9a. The ion concentration measuring units 6 and 7 detect lithium ion electrodes 16 and 17 according to JIS K0101, potentiometers 18 and 19 connected to the respective ion electrodes 16 and 17, and a sample temperature collected from each sampling port. It comprises digital thermometers 22 and 23. The boiler water collected from each of the collecting ports 8 and 9 is immersed in the ion electrodes 16 and 17, and the concentrations of the boiler water treatment chemicals are measured by potentiometers 18 and 19.

Further, the boiler plant 50 includes the on-off valve 8
a, 9a, electromagnetic blow valve 13, pump 12, potentiometer 1
8, 19 and a control unit 60 connected to the input / output units of the digital thermometers 22 and 23 and including a computer having a CPU, a ROM, a RAM, a timer, and the like.

An example of a boiler water treatment method by the boiler plant 50 based on the operation of the control unit 60 will be described with reference to the flowcharts of FIGS. The chemical used in Embodiment 1 is used as the boiler water treatment chemical. The pump 12 is driven so that the boiler water treatment chemical is continuously added to the water supply from the chemical tank 14 at a set discharge rate of 75 to 85 mg / L.
No. 3 indicates that the concentration of the chemical in the boiler is set at 1500 to 1700 mg
The discharge amount of the blow water is set to the set opening so as to be / L, and the blow water is continuously discharged from the boiler 1 via the blow water pipe 30. When the control unit 60 is started, a test program for testing a preset calibration curve is started (step S1). The assay program was prepared using a standard solution at a liquid temperature of 25 ° C. and stored in a calibration curve (for example, by setting the drug concentrations to 10 mg / L, 100 mg / L, 1000 mg / L,
000 mg / L, and the potential of each standard solution was measured)
The test is performed according to the water temperature detected by the digital thermometers 22 and 23.

Next, the on-off valves 8a and 9a are opened, and a predetermined amount is automatically collected from the sampling ports 8 and 9 using the water containing the boiler water treatment chemical and the boiler water as sample water. When the lithium ion electrodes 16 and 17 of the ion concentration measuring units 6 and 7 are immersed in the collected sample water, a drug concentration setting program is started (step S2). The drug concentration setting program includes the lithium ion electrodes 16 and 17
The indicated potentials of the potentiometers 18 and 19 connected to are read, and the water supply and the boiler 1 are read based on the calibrated calibration curve.
Then, the drug concentration f in the feed water and the drug concentration b in the boiler are calculated.

Next, the addition amount of the boiler water treatment chemical is adjusted based on the calculated water supply chemical concentration f. First, in step S3, the water supply agent concentration f of the water supply collected from the collection port 8 is compared with the set discharge amount. If it is determined that the water supply chemical concentration f is smaller than the set value, the process proceeds to step S4, and the pump 1 is controlled to increase the discharge amount of the boiler water treatment chemical.
2 is controlled. On the other hand, if the determination in step S3 is no, the process proceeds to step S5 to compare the water supply chemical concentration f of the water supply with the set discharge amount. If it is determined that the water supply chemical concentration f is higher than the set value, the process proceeds to step S6, and the pump 1 is controlled to reduce the discharge amount of the boiler water treatment chemical.
2 is controlled. Next, the above-described measurement and calculation are repeated until the water supply chemical concentration f becomes the set discharge amount 75 to 85 mg / L, and the water supply chemical concentration f becomes the set discharge amount 75 to 85 mg / L.
Is reached, the discharge amount of the pump 12 is returned to the set discharge amount (steps S7 to S8). If the determination in step S5 is no, the process proceeds to step S9 to determine whether or not the water supply medicine concentration f matches the set discharge amount of 75 to 85 mg / L. If the water supply chemical concentration f is within the range of the set discharge amount, the process proceeds to the next step S10.
Move to step S3.

Next, the discharge amount of the blow water is adjusted (the concentration of the boiler water is adjusted) based on the calculated chemical concentration b in the boiler. First, in step S10, the collection port 9
Is compared with the set concentration in the boiler water collected from the boiler. If it is determined that the chemical concentration b in the boiler is higher than the set concentration, the process proceeds to step S11, and the opening of the blow valve 13 is increased so that the discharge amount of blow water increases. On the other hand, if the determination in step S10 is no, the process shifts to step S12 to compare the boiler drug concentration b with the set concentration. If it is determined that the chemical concentration b in the boiler is smaller than the set concentration, the process proceeds to step S13, and the opening of the blow valve 13 is reduced so that the discharge amount of blow water is reduced. Next, the chemical concentration b in the boiler is set at
The above measurement and calculation are repeated until the concentration reaches ~ 1700 mg / L, and the concentration b of the medicine in the boiler becomes the set concentration of 1500 to 17
When it reaches 00 mg / L, the opening of the blow valve 13 is returned to the set opening (steps S14 to S15). Step S1
If the determination in No. 2 is no, the process proceeds to step S16, where the drug concentration b in the boiler is set to the set concentration 1500 to 170.
It is determined whether the value matches 0 mg / L. If the chemical concentration b in the boiler is within the range of the set concentration, the adjustment of the discharge amount of the blow water is finished, and if no, the process proceeds to step S10.

The above-described series of programs are executed at preset intervals or by interruption, and the change in the drug concentration in the boiler 1 over several days or months is monitored. The transition of the drug concentration is stored in a time chart. Note that the calibration curve calibration in the above-described calibration program is preferably performed when the gradient of the calibration curve does not greatly vary depending on the temperature of the sample water, but the sampling ports 8 and 9 are measured using the digital thermometers 22 and 23. It is also possible to measure the sample water gradually cooled to the ambient temperature by using.

Embodiment 3 FIG. 6 schematically shows a configuration of a boiler plant to which a boiler water treatment system of the present invention for automatically controlling boiler water treatment is applied. In FIG. 6, a boiler plant 70 includes a furnace tube smoke tube boiler 1, a water supply tank 2 disposed upstream of the boiler 1 via a water supply pipe 20, and a dissolved oxygen concentration meter that measures the concentration of dissolved oxygen in the feedwater. 72, a chemical tank 14 and a pump 12 for adding a boiler water treatment chemical to feed water, an electromagnetic blow valve 13 and a heat exchanger 5 disposed downstream of the boiler 1 via a blow water pipe 30, 1 is mainly constituted by a drain recovery pipe 40 in which the steam supplied from 1 is drained and recovered in the water supply tank 2. The pump 12 can arbitrarily set the amount of the boiler water treatment chemical added from the chemical tank 14 to the boiler water supply by controlling the frequency of the stepping motor. The blow valve 13 is configured such that its opening is proportional to the flow rate.
The discharge amount of blow water discharged through 0 can be arbitrarily set.

Further, a pump (not shown) for supplying water from the water supply tank 2 to the boiler 1 is provided in the water supply pipe 20. Further, the blow water pipe 30 has a pH meter 73 disposed downstream of the heat exchanger 5 and an ion concentration measuring unit 7 for measuring the concentration of a cation component and / or an anion component in the blow water. Concentration measuring unit 7
Is connected to a sampling port 9 for sampling, which is provided in the blow water pipe 30 and has an electromagnetic on-off valve 9a. The ion concentration measuring unit 7 includes a lithium ion electrode 17 according to JIS K0101, a potentiometer 19 connected to the ion electrode 17, and a digital thermometer 23 for detecting a temperature of a sample collected from the sampling port 9. The boiler water collected from the collection port 9 is immersed in the ion electrode 17, and the concentration of the boiler water treatment chemical is measured by the potentiometer 19.

Further, the boiler plant 70 includes the on-off valve 9
a, electromagnetic blow valve 13, pump 12, potentiometer 19, digital thermometer 23, dissolved oxygen concentration meter 72, and pH meter 7
3 is connected to each input / output unit, and a CPU, a ROM, a RAM,
The control unit 80 includes a computer having a timer and the like.

An example of a boiler water treatment method by the boiler plant 70 based on the operation of the control unit 80 will be described. Table 2 shows the configuration of the boiler water treatment chemical supplied from the chemical tank 14.

[0053]

[Table 2]

The above-mentioned boiler water treatment chemical is a one-pack type boiler water treatment chemical containing sodium sulfite as an oxygen scavenger [trade name: Miracle FD530 manufactured by Katayama Chemical Industry Laboratory / Miracle is ( (Registered trademark of Katayama Chemical Industry Laboratory Co., Ltd.). Dissolved oxygen concentration meter 72
Used DO30A manufactured by Toa Denpa Kogyo KK p
As the H meter 73, HM-21P manufactured by Toa Denpa Kogyo KK was used.

The pump 12 sets the discharge amount of the boiler water treatment chemical based on the dissolved oxygen concentration in the boiler feed water. When using the one-pack type boiler water treatment chemicals in Table 2, the dissolved oxygen concentration is 1 mg / L and the sodium sulfite is 7.9 mg / L.
Is required, the discharge amount of the boiler water treatment chemical is set based on this. Further, the blow valve 13 is initially held in a state set to the standard setting opening. The boiler plant 70 has a drain recovery rate of 0 at 0.7 MPa.
Operating conditions were set to be ~ 50%.

The operation of the control unit 80 according to the third embodiment will be described with reference to the flowcharts of FIGS. As shown in the flowchart of FIG. 7, the boiler plant 70 sequentially starts a second test program (P1), a second drug concentration setting program (P2), a blow setting program (P3), and a pH correction program (P4) described later. By doing so, boiler water is managed. Fig. 8-
FIG. 10 is a flowchart illustrating each routine of the programs P2 to P4.

In FIG. 7, when the control section 80 is started, a second test program (step P1) for testing a preset calibration curve is started. Test 2
The program was created using standard solutions at a liquid temperature of 25 ° C and stored a calibration curve (for example, the potential of each standard solution with lithium ion drug concentrations of 1 mg / L, 10 mg / L, and 100 mg / L, respectively). The test is performed in accordance with the water temperature detected by the digital thermometer 23 using a relational expression showing a correlation between the oxygen content and the oxygen absorber based on the dissolved oxygen concentration measurement result obtained by the dissolved oxygen concentration meter 72. Next, a second drug concentration setting program is started (step P2).

The second drug concentration setting program (P2)
As shown in the flowchart of FIG. 8, first, the dissolved oxygen concentration A (mg / L) in the feed water was measured by the dissolved oxygen concentration meter 72 (step S21). Next, in step S22, the drug addition concentration A × B is set based on the second test program set in P1. B is a coefficient based on the concentration ratio of sodium sulfite ion in the boiler water treatment chemical, and is 40 in this example. Next, the frequency of the pulse to be supplied to the motor of the pump 12 was set based on the set drug addition concentration A × B, and the pump 12 was driven under the set conditions (steps S23 and S24). When the stop of the control by the second drug concentration setting program (P2) is commanded, the process proceeds to the blow setting program (P3) (step S25).

As shown in the flowchart of FIG. 9, the blow setting program (P3) first sets the drug concentration setting second.
Drug addition concentration A obtained in step S22 of the program
XB was multiplied by a coefficient C indicating the concentration ratio of lithium ions in the boiler water treatment chemical to obtain a chemical addition concentration AxBxC. In this example, C is 0.003. Further, the boiler concentration ratio was set. The set enrichment ratio Z is
Usually, it is 10 to 20, but here, it is set to 10 (times) (step S31). Next, in step S32, the lithium concentration D
(Mg / L) was measured. Next, in step S33, the actual boiler concentration ratio was calculated based on the measured values of the drug addition concentration A × B × C and the lithium concentration D.
This measurement concentration E can be obtained from D / (A × B × C). Next, in step S34, each numerical value of the set concentration ratio Z and the measured concentration ratio E was compared.

In the above comparison result, when Z <0.9E, the electromagnetic blow valve 13 is further opened by 10% from the standard opening degree (steps S35 and S36), and Z>
When the value reaches 1.1E, the electromagnetic blow valve 13 is further closed by 10% from the standard opening degree (steps S37 and S3).
8), when 0.9E ≦ Z ≦ 1.1E, the electromagnetic blow valve 13 is kept at the standard setting opening (step S3).
9). When the stop of the control by the blow setting program (P3) is commanded, the process shifts to the pH correction program (P4) (step S40).

As shown in the flowchart of FIG. 10, the pH correction program (P4) first measured the pH value F in the boiler water with the pH meter 73 (step S41). Next, in step S42, each of the numerical values of the preset pH value widths G to H was compared with the measured pH value F.

In the above comparison result, when F <G, the standard opening degree of the electromagnetic blow valve 13 is further increased by one.
0% closed (steps S43 and S44), and when F> H, the electromagnetic blow valve 13 is further opened by 10% from the standard opening degree (steps S45 and S46), and G ≦ F.
If ≤H, the electromagnetic blow valve 13 is kept at the standard setting opening (step S47). When the stop of the control by the pH correction program (P4) is commanded, the process returns to the second drug concentration setting program (P2) (step S48).

The above series of programs are executed within a predetermined period, and the transition of the drug concentration in the boiler 1 measured every day or every other day during this period is shown in FIGS. As shown in FIG. 11, the drug addition rate based on the measurement of the dissolved oxygen concentration is:
There was little change from the set value without much change.

FIG. 12 is a graph showing the pH value obtained by the pH correction program.
The drug addition rate and the blow rate (measurement concentration ratio E) based on the measurement of the dissolved oxygen concentration without correction are shown. In this case, the chemical addition rate and the blow rate based on the measurement of the dissolved oxygen concentration do not greatly deviate from the set values and change little, indicating that the blow water is managed substantially as set.

FIG. 13 is a graph showing the pH obtained by the pH correction program.
9 shows the drug addition rate and the blow rate (measurement concentration ratio E) based on the measurement of the dissolved oxygen concentration when the correction is performed. In this case, the chemical addition rate and the blow rate based on the measurement of the dissolved oxygen concentration do not greatly deviate from the set values and change little, indicating that the blow water is managed substantially as set.

FIG. 14 shows a change in pH of the boiler water.
As is clear from FIG. 14, the measurement date 2000 in FIG.
The case where the pH correction was not performed at the boundary of / 1/20 (FIG. 12) and the case where the pH correction was performed (FIG. 13)
The distribution of measured values is different. In other words, after the measurement date 2000/1/20 after the pH correction, the water is distributed within the pH range (pH 11.0 to 11.8) specified in JIS B8223, and the management of blow water is performed almost as set. You can see that it is done.

In the third embodiment, the chemical adding means is controlled based on the measurement of the dissolved oxygen concentration, and the blow water amount control means is controlled based on the measurement of the ion concentration measuring part. , And can be added accurately, and blow water can be accurately controlled. In the third embodiment, the control of the addition amount of the oxygen absorber of the present invention used in the boiler plant 70 having no deaerator has been described. It is clear that the control of is possible. When a carboxylate ion electrode is used as the ion electrode 17, it is preferable to measure the dissolved oxygen concentration by further connecting a dissolved oxygen concentration meter 72 to the upstream side of the ion electrode 17, for example, to the sampling port 9.

Another Embodiment FIG. 5 shows the structure of a carboxylate ion electrode used in the boiler water treatment method and boiler water treatment system of the present invention. This carboxylate ion electrode is described in Kobe Women's Junior College, 39, 57-71 (199
4) ”, and the description is omitted.

[0069]

According to the method of the present invention, the two-stage measurement of the chlorine ion concentration in the boiler water system and the measurement of the residual treatment agent concentration are not required, and the pure water boiler in which chlorine ions do not exist in the boiler water is not required. It is possible to provide a boiler water treatment method and a boiler water treatment system that can also be applied.

By measuring the concentration of the cation or anion component in the boiler water which correlates with the concentration of the boiler water treatment chemical in the feed water and boiler water, the concentration of the boiler water treatment chemical in the boiler water can be grasped. By controlling the concentration of the boiler water and / or the amount of the chemical for treating the boiler water, the water treatment of the boiler can be managed simply, quickly and accurately. Further, in the treatment method of the present invention, since the use of an organic solvent when measuring the concentration of the residual drug is not required, the safety on site can be improved.

Therefore, in various types of boilers, it is possible to cope with a change in the flow rate and water quality of the boiler feed water as needed.
A highly safe boiler water treatment method and a boiler water treatment system capable of easily and quickly managing a boiler are provided. The boiler water treatment system and the boiler water treatment system are provided. The generation of scale can be suppressed, and failures and accidents of the superheater and turbine due to carryover can be prevented.

Further, since the addition amount of the oxygen scavenger can be accurately controlled, it is possible to respond to changes in the flow rate and water quality of the boiler feed water at any time, so that boiler management can be performed simply and quickly, and safety can be improved. improves. Since the excessive addition of the oxygen scavenger can be prevented, the trouble accompanying the addition of the oxygen scavenger can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram schematically showing a configuration of a boiler plant in which a boiler water treatment method of the present invention has been implemented.

FIG. 2 is a graph showing changes in the concentration of a boiler water treatment chemical measured in the boiler plant of FIG.

FIG. 3 is a schematic diagram schematically showing a configuration of a boiler plant to which the boiler water treatment system of the present invention is applied.

FIG. 4 is a flowchart of a boiler water treatment system applied to the boiler plant of FIG.

FIG. 5 is a front sectional view showing a configuration of a carboxylate ion electrode used in the present invention.

FIG. 6 is a schematic diagram schematically showing a configuration of a boiler plant to which the boiler water treatment system of the present invention is applied.

FIG. 7 is a flowchart of a boiler water treatment system applied to the boiler plant of FIG.

FIG. 8 is a flowchart illustrating a subroutine of a second drug concentration setting program in FIG. 7;

FIG. 9 is a flowchart illustrating a subroutine of the blow setting program of FIG. 7;

FIG. 10 is a flowchart illustrating a subroutine of the pH correction program of FIG. 7;

FIG. 11 is a graph showing the transition of the drug addition rate based on the measurement of the dissolved oxygen concentration of the present invention.

FIG. 12 is a graph showing a drug addition rate and a blow rate based on the measurement of the dissolved oxygen concentration of the present invention.

FIG. 13 is a graph showing a drug addition rate and a blow rate based on the measurement of the dissolved oxygen concentration of the present invention.

FIG. 14 is a graph showing a change in the pH of boiler water due to the addition of a chemical performed based on the measurement of the dissolved oxygen concentration according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler 2 Water supply tank 3 Blow valve 4 Chemical tank 5 Heat exchanger 6 Ion concentration measuring part 7 Ion concentration measuring part 8 Sampling port 8a Open / close valve 9 Sampling port 9a Open / close valve 10 Boiler plant 12 Pump 13 Blow valve 14 Chemical tank 20 Water supply Pipe 30 Blow water pipe 40 Drain recovery pipe 50 Boiler plant 60 Control unit 70 Boiler plant 72 Dissolved oxygen concentration meter 73 pH meter 80 Control unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23F 11/12 101 C23F 11/12 101 11/18 11/18 14/02 14/02 A G01N 27/416 G01N 33/18 D 33/18 F22B 37/56 A // F22B 37/56 G01N 27/46 351B 351J (72) Inventor Takeyuki Otani 2-10-15 Higashiawaji, Higashiyodogawa-ku, Osaka-shi, Osaka Katayama Chemical Co., Ltd. F-term in the Industrial Research Laboratory (reference) 4D037 AA08 BA23 4D038 AA05 AB27 4K062 AA03 BA05 BB06 CA03 CA10 DA01 EA20 FA02 FA06 GA10

Claims (15)

[Claims] When a boiler water treatment is performed by adding a boiler water treatment agent to boiler water of a soft water boiler or a pure water boiler, a cation or anion component which is not substantially contained in the soft water or the pure water is treated. A boiler water treatment method characterized by adding to a boiler water as a chemical or separately, measuring the concentration in the boiler water with an ion electrode, and managing the boiler water based on the result. 2. The boiler water treatment method according to claim 1, wherein the concentration of the boiler water and / or the amount of the boiler water treatment chemical added is controlled based on the measurement result by the ion electrode. 3. The boiler water treatment method according to claim 1, wherein the cation or anion component is a monovalent or divalent cation or anion. 4. The boiler water treatment method according to claim 1, wherein the cation component is a lithium ion and the anion component is a carboxylate ion. 5. A method for calculating the concentration of residual chemicals in boiler water and / or the degree of concentration of boiler water from the measurement result obtained by the ion electrode, and adding the amount of chemicals for treating boiler water and / or discharging blow water from the boiler based on the results. The boiler water treatment method according to any one of claims 1 to 4, wherein the amount is controlled. 6. A deoxygenating means for removing oxygen in boiler water, wherein the dissolved oxygen concentration in the boiler feedwater is measured by a dissolved oxygen concentration meter, and the driving of the deoxygenating means is controlled based on the result. The boiler water treatment method according to any one of the above. 7. The boiler water treatment method according to claim 1, wherein the pH of the blow water from the boiler is measured, and the discharge amount of the blow water from the boiler is controlled based on the result. 8. A chemical adding means for adding a boiler water treatment chemical to boiler water of a soft water boiler or a pure water boiler; a blow water amount controlling means for controlling an amount of blow water discharged from the boiler; An ion concentration measuring unit for measuring the concentration of the component or the anion component, and a drug adding means and / or
Or a control unit for controlling the blow water amount control means, wherein the ion concentration measurement unit is constituted by an ion electrode for measuring the concentration in the boiler water of a cation component or an anion component substantially not contained in soft water or pure water. A boiler water treatment system characterized in that: 9. The boiler water treatment system according to claim 8, wherein the ion electrode is a lithium electrode for measuring the concentration of lithium ions or a carboxylic acid electrode for measuring the concentration of carboxylate ions. 10. The boiler water treatment system according to claim 8, wherein the chemical addition means adds the cation or anion component as a boiler water treatment chemical or separately to boiler water. 11. A deoxygenating means for removing oxygen in boiler water, and a dissolved oxygen concentration meter for measuring dissolved oxygen concentration in boiler feedwater, wherein the control unit is configured to control the dissolved oxygen concentration measured by the dissolved oxygen concentration meter. The boiler water treatment system according to claim 8, wherein the deoxygenating means is controlled based on the concentration. 12. The boiler water treatment system according to claim 11, wherein the deoxidizing means is a deaerator and / or a deoxidizing agent added to the boiler water system by a chemical adding means interposed in the boiler water supply system. 13. The boiler water treatment system according to claim 12, wherein the oxygen scavenger is added to the boiler water treatment chemical and added to the boiler water together with the boiler water treatment chemical or separately from the boiler water treatment chemical. 14. The boiler water treatment system according to claim 11, wherein the dissolved oxygen concentration meter measures the dissolved oxygen concentration in the boiler water upstream of the chemical adding means. 15. The apparatus according to claim 8, further comprising a pH meter for measuring the pH of the blow water from the boiler, wherein the control unit controls the blow water amount control means based on the pH of the boiler water measured by the pH meter. Boiler water treatment system.