Boiler water quality evaluation system

Abstract

To enhance usefulness as an index for water quality adjustment of boiler water in water quality evaluation of the boiler water in a boiler in operation.SOLUTION: The water quality evaluation system 20 of the boiler water in the boiler main body 120 in operation includes a determination part 400 for determining the timing of collecting the boiler water from the boiler main body 120 in operation, and an analysis part 300 for evaluating the water quality of the boiler water. The determination unit 400 determines a timing of collecting the boiler water from the boiler main body 120 based on an operation state of the boiler main body 120 such as a concentration progress degree of the boiler water in the boiler main body 120 in operation. The analysis unit 300 prepares sample water for evaluating the water quality of the boiler water from the boiler water collected at the time determined by the determination unit 400, and evaluates the water quality of the boiler water using the sample water.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a boiler water quality evaluation system, and more particularly to a boiler water quality evaluation system for boiler water in an operating boiler. [Background technology]

[0002] A typical boiler system for supplying steam to load equipment such as heat exchangers generates steam by heating boiler feedwater as boiler water, and supplies this steam to the load equipment through a steam line. Because the inside of a boiler is a high-temperature, high-pressure environment, the heat transfer surfaces of the water tubes that generate the steam can become corroded or scale can form on them due to the influence of various dissolved components in the feedwater. Scale that forms on the heat transfer surfaces impedes heat conduction, reducing the boiler's operating efficiency. Furthermore, if corrosion of the heat transfer surfaces progresses, it can damage the water tubes, hindering the stable and continuous operation of the boiler.

[0003] Therefore, when operating a boiler system, calcium ions and magnesium ions that cause scale are usually removed from the water supplied to the boiler, as well as dissolved oxygen that causes corrosion.In addition, the quality of the boiler water is adjusted by adding various water treatment agents to the supply water and controlling the concentration rate of the boiler water, in order to suppress the formation of scale and the progression of corrosion in the boiler.

[0004] For example, Patent Document 1 discloses a system that automatically collects boiler water from a boiler during combustion based on the duration of combustion, analyzes the water quality, and adjusts the quality of the boiler water by controlling the addition of a water treatment agent to the boiler water and the concentration ratio in light of the results. This system makes it possible to determine the quality of the boiler water in real time and quickly reflect the results in adjusting the quality of the boiler water, thereby enabling appropriate management of the operation of the boiler equipment.

[0005] On the other hand, the boiler water quality of an operating boiler is unstable due to a variety of factors, including fluctuations in the quality of the raw water used for feedwater and the boiler's operating history, such as its operating rate (e.g., steam generation rate), and the factors that cause fluctuations in water quality are complex. Therefore, standard water quality assessments based on the boiler's continuous combustion time are not very useful as indicators for adjusting the water quality of boiler water, and water quality adjustments based on such water quality assessments may not be timely. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-162200 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to improve the usefulness of the water quality evaluation of boiler water in an operating boiler as an index for adjusting the water quality of the boiler water. [Means for solving the problem]

[0008] The present invention relates to a boiler water quality evaluation system for a boiler in operation. The water quality evaluation system includes a determination unit that determines when to sample boiler water from the boiler based on the boiler's operating status, and an analysis unit that evaluates the boiler water quality. The analysis unit includes a boiler water treatment unit that samples boiler water from the boiler at the time determined by the determination unit and prepares sample water for boiler water quality evaluation, and evaluates the boiler water quality using the sample water prepared by the boiler water treatment unit.

[0009] In one embodiment of the water quality evaluation system of the present invention, the analysis unit is equipped with multiple analyzers for evaluating multiple water quality items of boiler water, and the boiler water processing unit uses boiler water collected at the time determined by the judgment unit to prepare sample water for the multiple analyzers.

[0010] In this embodiment, the boiler water processing section prepares sample water for each of the multiple analyzers, for example.

[0011] In the water quality evaluation system of the present invention, the sample water prepared by the boiler water treatment unit is, for example, a primary sample water obtained by cooling collected boiler water or a secondary sample water obtained by diluting the primary sample water.

[0012] In another form of the water quality evaluation system of the present invention, the boiler is a group of boilers consisting of multiple individual boilers, and the judgment unit selects an individual boiler from the group of boilers from which boiler water will be collected by the boiler water processing unit based on the operating status of each individual boiler. [Effects of the Invention]

[0013] The boiler water quality evaluation system of the present invention determines the time to collect boiler water from the boiler based on the operating conditions of the boiler in a judgment unit, and also collects boiler water from the boiler at the time determined by the judgment unit in a boiler water treatment unit to prepare sample water for evaluating the boiler water quality, thereby increasing the usefulness of the boiler water quality evaluation in the analysis unit as an indicator for adjusting the boiler water quality. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram of a boiler apparatus equipped with one embodiment of a boiler water quality evaluation system according to the present invention; [Figure 2] 2 is a schematic diagram of a boiler unit of the boiler device. FIG. [Figure 3] FIG. [Figure 4] FIG. 3 is a schematic diagram of a determination unit according to the embodiment. [Figure 5] 10 is a flowchart of a water quality evaluation program according to the embodiment. [Figure 6] FIG. 10 is a schematic diagram of a modified example of a part of the analysis unit in the embodiment. [Figure 7] FIG. 10 is a schematic diagram of another modified example of a part of the analysis section in the embodiment. [Figure 8]FIG. 10 is a schematic diagram of a modified example of the boiler unit of the boiler device. DETAILED DESCRIPTION OF THE INVENTION

[0015] An example of a boiler apparatus equipped with one embodiment of a boiler water quality evaluation system according to the present invention will be outlined below with reference to Fig. 1. In Fig. 1, the boiler apparatus 1 mainly comprises a boiler section 10, a boiler water quality evaluation system 20, and a control section 30 for controlling the operation of the boiler apparatus 1.

[0016] The boiler section 10 is intended to supply steam to a load device 110, which is steam-using equipment such as a heat exchanger, steam boiler, reboiler, or autoclave, and as shown in Figure 2, mainly comprises a boiler body 120, a water supply device 130, and a chemical supply device 140.

[0017] The boiler body 120 has a large number of standing water pipes (not shown) inside, stores water supplied from the water supply device 130 as boiler water, and generates steam by heating this boiler water through the heat transfer surfaces of the water pipes. The boiler body 120 has a blow path 121 for discharging a portion of the boiler water, and this blow path 121 has a first control valve 122 for adjusting the amount of boiler water discharged. Furthermore, a steam supply pipe 123 that connects to the load device 110 extends from the top of the boiler body 120.

[0018] The water supply device 130 supplies feedwater to be used as boiler water in the boiler body 120, and typically extends from a water supply tank (not shown) for storing feedwater that has been treated to remove hardness components and dissolved oxygen from raw water supplied from a water source such as tap water, industrial water, or groundwater, and has a water supply path 131 that connects to the bottom of the boiler body 120. The water supply path 131 has a water supply pump (not shown) for sending the feedwater stored in the water supply tank to the boiler body 120.

[0019] The chemical supply device 140 adds a water treatment agent to the feedwater supplied from the water supply device 130 to the boiler body 120, and is capable of controlling the timing and amount of addition of the water treatment agent based on operational commands from the control unit 30. Examples of water treatment agents include pH adjusters, scale dispersants, and anticorrosive agents. The pH adjuster adjusts the pH of the boiler water to an alkaline range to suppress corrosion within the boiler body 120. For example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are used. The scale dispersant suppresses scale formation within the boiler 120 by sealing out hardness components remaining in the feedwater. For example, chelating agents such as ethylenediaminetetraacetic acid (EDTA) and polymer compounds such as polyacrylic acid compounds are used. The anticorrosive agent suppresses corrosion of the water pipes and the like within the boiler body 120. Typically, oxygen scavengers or film-forming agents are used. The oxygen scavengers remove dissolved oxygen remaining in the feedwater. For example, ascorbic acid or sulfites are used. The film-forming agent forms an anticorrosive film on water pipes and the like, and is, for example, a silicate-based compound such as silicon dioxide. The water treatment agent may be supplied individually from the chemical supply device 140 to the water supply, or may be supplied as a composite agent in which multiple types of water treatment agent are premixed. The water treatment agent may also contain a tracer substance for determining the amount of water treatment agent added to the water supply. For example, a fluorescent dye is used as the tracer substance.

[0020] The water quality evaluation system 20 is for evaluating the quality of boiler water from an operating boiler unit 10, and mainly comprises a determination unit 400 for determining when to sample boiler water from the operating boiler unit 10, and an analysis unit 300 for evaluating the quality of the sampled boiler water. The determination unit 400 is incorporated into the control unit 30 and operates as part of the control unit 30. The analysis unit 300 has a boiler water treatment unit 200 that samples boiler water from the boiler unit 10 at the time determined by the determination unit 400 and prepares sample water for evaluating the water quality of the boiler water.

[0021] As shown in FIG. 3, the boiler water treatment unit 200 mainly includes a collection path 210, a cooler 220, a pressure reducer 230, a water storage tank 240, a water supply path 250, and a supply path 260 for dilution water.

[0022] The collection path 210 branches off from the blow path 121 on the upstream side of the first control valve 122 (FIG. 2), and has a second control valve 211 for adjusting the flow of boiler water from the boiler body 120.

[0023] Cooler 220 is a water-cooled heat exchanger and includes a refrigerant jacket 221 that houses a portion of collection path 210. Refrigerant jacket 221 includes an inlet path 212 equipped with a first on-off valve 213 for introducing cooling water as a refrigerant, and an outlet path 214 for discharging the introduced cooling water. Inlet path 212 branches off from a path that supplies raw water or softened water that has been processed to remove hardness components from raw water to water supply device 130. Collection path 210 has a coil portion 223 formed in a portion housed within refrigerant jacket 221, and its tip extends from refrigerant jacket 221 to water tank 240.

[0024] The pressure reducer 230 is a throttling mechanism arranged in the collection path 210 between the refrigerant jacket 221 and the water tank 240, and is, for example, a constant flow valve or an orifice. However, it is preferable to use a constant flow valve because it is easier to stabilize the cooling capacity of the boiler water in the cooler 220, which is a water-cooled heat exchanger.

[0025] The water tank 240 is a container for storing boiler water from the collection path 210 and is open to the atmosphere, and mainly includes a first overflow path 241, a drainage path 242, and a water volume adjustment path 243. The water tank 240 also includes a first analyzer 310 on its top. The first analyzer 310 is a sensor for measuring the electrical conductivity of the boiler water, and also for detecting that the boiler water, etc. has been stored in the water tank 240 up to a predetermined water level.

[0026] The first overflow path 241 limits the amount of stored water by allowing boiler water to overflow when a certain amount of boiler water or more is supplied, and is connected to a discharge path 214 from the cooler 220. The drainage path 242 extends from the bottom of the water tank 240 and is connected to the discharge path 214 from the cooler 220, and has a second on-off valve 244 for controlling the discharge of boiler water stored in the water tank 240. The water amount adjustment path 243 extends from between the bottom of the water tank 240 and the first overflow path 241 and is connected to the discharge path 214 from the cooler 220, and has a third on-off valve 245.

[0027] The water supply path 250 extends from near the bottom of the water tank 240 and is connected to the analysis section 300, and has a pump 251 for pumping out the boiler water stored in the water tank 240. Further, downstream of the pump 251, the water supply path 250 branches off into a circulation path 252 whose tip is connected to the top of the water tank 240, and this circulation path 252 has a fourth on-off valve 253.

[0028] Dilution water supply path 260 has a main path 261 branching off from cooling water inlet path 212 on the downstream side of first on-off valve 213, and a sub-path 262 branching off from main path 261. Main path 261 is equipped with an activated carbon filter 263 and an ion exchange resin filter 264 arranged in series from upstream to downstream, and its tip is connected to metering tank 265. In addition, main path 261 has a fifth on-off valve 266 between ion exchange resin filter 264 and metering tank 265.

[0029] The metering tank 265, which is connected to the main passage 261, is capable of storing a predetermined amount of dilution water, and is provided with a second overflow passage 267 that allows the dilution water to overflow when the dilution water exceeds the predetermined amount, and a communication passage 268 that extends from the bottom to the storage tank 240. The second overflow passage 267 is connected to the discharge passage 214 from the cooler 220, and the communication passage 268 has a sixth on-off valve 269.

[0030] The sub-path 262 branches off from the main path 261 between the activated carbon filter 263 and the ion exchange resin filter 264 , has a seventh on-off valve 270 , and is connected to the reservoir tank 240 at its tip.

[0031] The analysis unit 300 further includes a second analyzer 320, a third analyzer 330, and a fourth analyzer 340 connected to the water supply path 250. The second analyzer 320 and the third analyzer 330 are colorimeters that use colorimetry to measure the evaluation water quality parameters of the water sample, such as pH, silica concentration, chloride ion concentration, sulfate ion concentration, hardness, or iron concentration. The colorimeters of the analyzers 320 and 330 each include a cell (not shown) for storing the water sample, and this cell is equipped with multiple pairs of sensors (not shown) each consisting of a light-emitting element and a light-receiving element corresponding to the measurement parameters so as to accommodate multiple measurement parameters. The cell is also connected to a reagent supply device (not shown) that can select and add a color-developing reagent corresponding to the measurement parameter to the water sample stored in the cell.

[0032] The fourth analyzer 340 is a fluorometer for measuring a fluorescent dye when the water treatment agent added to the supply water from the chemical supply device 140 contains the fluorescent dye as a tracer substance. The fluorometer is equipped with a cell for storing the sample water, and an excitation light source and a detector are arranged relative to this cell.

[0033] Each of the analyzers 320, 330, and 340 has a first inlet valve 321, a second inlet valve 331, and a third inlet valve 341, respectively, for introducing sample water from the water supply path 250 into the cell, and also has a first waste water channel 322, a second waste water channel 332, and a third waste water channel 342, respectively, for discharging the sample from the cell. Each of the waste water channels 322, 332, and 342 is connected to the discharge path 214 from the cooler 220.

[0034] The control unit 30 is a computer equipped with an operating program for controlling the operation of the boiler apparatus 1, and includes a processing device 410 equipped with an information input unit 420 and a command output unit 430, as shown in FIG. 4. The operating program includes a subprogram for evaluating the quality of boiler water, which functions as the judgment unit 400 of the water quality evaluation system 20. The processing device 410 includes a memory device for storing various types of information and a timer for measuring the operating time of the boiler main body 120. The information input unit 420 sends input information from the operation panel, operating information of the boiler main body 120, measurement results from the analysis unit 300, and other information to the processing device 410. In addition to the operation panel, the information input unit 420 is connected to the electrodes for measuring the electrical conductivity within the boiler main body 120, thermocouples for measuring the temperature of the heat transfer surfaces of the water tubes, and the analyzers 310, 320, 330, and 340 installed in the boiler main body 120. The command output unit 430 is used to send the required display information from the processing device 410 to a display panel that shows the operating status of the boiler device 1, and to send the required operating commands to each part of the boiler device 1.In addition to the display panel, it is connected to the control valves, pumps, chemical supply device 140 and other operating parts of each part of the boiler unit 10, as well as the control valves, on-off valves, pumps and other operating parts of each part of the analysis unit 300.

[0035] The boiler apparatus 1 basically operates as follows in accordance with the operation program of the control unit 30.

[0036] In the boiler apparatus 1, feedwater is supplied to the boiler body 120 from a feedwater tank by a feedwater pump via a feedwater path 131. The boiler body 120 stores the supplied feedwater as boiler water and generates steam by heating the boiler water through the heat transfer surfaces of the water pipes. This steam is supplied to the load device 110 via steam supply piping 123. During this process, a required water treatment agent is added to the feedwater supplied to the boiler body 120 from the feedwater path 131 in a timely manner from an chemical supply device 140. Furthermore, since the boiler water is concentrated by the generation of steam, a portion of the boiler water is discharged via the blow path 121 by appropriately opening and closing the first control valve 122, and the concentration level is controlled by the replenished feedwater.

[0037] In the boiler apparatus 1 that operates as described above, while the boiler main body 120 is in operation, the water quality evaluation system 20 evaluates the water quality of the boiler water based on the water quality evaluation program of the judgment unit 400, and based on the evaluation results, controls the addition of water treatment agents to the feedwater from the chemical supply device 140, and controls the discharge of a portion of the boiler water through the blow path 121, thereby controlling the water quality of the boiler water in the boiler main body 120 to be suitable for corrosion prevention and scale inhibition.

[0038] Water quality evaluation using the water quality evaluation program basically involves collecting a portion of high-temperature, high-pressure boiler water from the boiler body 120 in the analysis unit 300 to prepare sample water for evaluating the water quality, and then using this sample water to evaluate the required water quality items.

[0039] The water quality evaluation process by the water quality evaluation program will be described with reference to Figure 5. The water quality evaluation program determines in step S1 whether the boiler body 120 has started operating, and when the boiler water 120 has started operating, proceeds to step S2, where it performs initial settings such as operating a timer in the treatment device 410 to start measuring the operating time of the boiler body 120.

[0040] After the initial settings are complete, the water quality evaluation program proceeds to step S3, where it acquires information about each part of the boiler body 120 in operation, such as the operating time of the boiler body 120 measured by the timer and the operating information sent to the information input unit 420, i.e., the combustion time, the electrical conductivity inside the boiler body 120 measured by the electrode, the temperature of the heat transfer surface of the water tube measured by the thermocouple, the feedwater amount, and the amount of boiler water discharged (blowdown amount) through the blowdown path 121 controlled by the first control valve 122, and continuously monitors the operating status of the boiler body 120 throughout the operation of the boiler body 120. Then, in step S4, the water quality evaluation program determines the timing to sample boiler water from the boiler body 120 based on the operating status being monitored.

[0041] The degree of concentration of the boiler water can be used as a criterion for determining when to collect boiler water based on the operating status of the boiler body 120. The degree of concentration of the boiler water can be evaluated in light of the above-mentioned operating information. Generally, the time elapsed since the start of operation of the boiler body 120, the electrical conductivity and heat transfer surface temperature of the water pipes inside the boiler body 120, the amount of feedwater, and the amount of boiler water blown down are used as indicators for evaluating the degree of concentration, but here, one or more of these operating information are appropriately selected, and the degree of concentration is evaluated in light of the selected operating information.

[0042] Furthermore, the timing of boiler water sampling based on the degree of concentration of the boiler water can be determined in light of the boiler water conditions that need to be evaluated, such as the corrosion progression trend, the concentration of the water treatment agent supplied via the water supply from the chemical supply device 140, or the tendency for scale formation. The concentration of the water treatment agent is a condition related to both the corrosion progression trend and the tendency for scale formation. Table 1 shows examples of combinations of operational information referenced to determine the degree of concentration of the boiler water conditions and water quality items evaluated by the analysis unit 300.

[0043] [Table 1]

[0044] When the water quality evaluation program determines that the degree of concentration of the boiler water has reached a state where evaluation of any of Examples 1 to 4 is required, the water quality evaluation program proceeds from step S4 to step S5, and the boiler water treatment unit 200 performs the sample water preparation process and analysis process 1.

[0045] In the sample water preparation process, in the boiler water treatment unit 200, the first on-off valve 213 is opened to continuously introduce cooling water into the refrigerant jacket 221 through the inlet path 212, and the cooling water pressed out from the refrigerant jacket 221 is continuously flowed to the outlet path 214. At the same time, the second control valve 211 is controlled to send a portion of the boiler water in the boiler body 120 from the blow path 121 to the collection path 210. The boiler water sent to the collection path 210 is cooled by the cooling water in the refrigerant jacket 221 as it passes through the coil section 223. The cooled high-pressure boiler water is reduced in pressure by passing through the pressure reducer 230 and stored in the water storage tank 240. Here, the boiler water is usually cooled to 40°C or below, which is a temperature suitable for water quality measurement.

[0046] The boiler water flowing from the collection path 210 into the water tank 240 is cooled and then depressurized, thereby suppressing the generation of flash steam that causes fluctuations in water quality. As a result, the boiler water stored in the water tank 240 is maintained at the same water quality as the boiler water in the boiler body 120, and is used as sample water (primary test water) for evaluating the water quality.

[0047] In evaluating the quality of boiler water, if the amount of boiler water collected is too large, it can result in instantaneous energy loss and affect the operation control of the boiler body 120. Furthermore, it is also necessary to increase the amount of cooling water required to cool the boiler water in the cooler 220. Therefore, it is preferable to limit the amount of boiler water stored in the water tank 240 to the amount necessary for analysis by the analysis unit 300. Therefore, in the water tank 240, the first analyzer 310, which is an electrical conductivity sensor, detects a rise in the water level in the water tank 240 due to the inflow of boiler water from the collection path 210, and controls the timing of closing the second control valve 211 accordingly. This stops the supply of boiler water to the water tank 240, and boiler water that flows into the water tank 240 above a predetermined water level overflows into the first overflow path 241. As a result, the amount of boiler water collected is not increased unnecessarily, and the required amount of boiler water is stored in the water tank 240.

[0048] When a predetermined amount of boiler water is stored in the water tank 240, the fourth on-off valve 253 is opened and the pump 251 is operated for a predetermined time. As a result, the boiler water stored in the water tank 240 is sent from the water supply path 250 to the circulation path 252 and returned to the water tank 240. As a result, the boiler water is circulated and agitated, thereby improving the homogeneity of the water quality in the water tank 240. When the pump 251 stops after the predetermined time has elapsed, the fourth on-off valve 253 is also closed, stopping the circulation of the boiler water. The electrical conductivity of the sample water (primary test water) stored in the water tank 240 in this manner is measured by the first analyzer 310 (analysis step 1).

[0049] After the water sample preparation process and analysis process 1 are completed, the water quality evaluation program proceeds to step S6, where it executes a process for allocating and configuring analyzers. Here, it is determined whether any of the water quality items to be subsequently evaluated require dilution of the water sample (primary test water). For example, as boiler water becomes more concentrated, water quality items such as silica concentration and chloride ion concentration often become higher in concentration than other water quality items. If the boiler water stored in the water storage tank 240 is used as the water sample as is, the measurement range of the analyzer 300 may be significantly exceeded or measurement accuracy may be impaired. Therefore, if any of these water quality items is present, the water sample must be diluted to the required ratio in the water storage tank 240 and used as the water sample (secondary test water).

[0050] When it is determined in step S4 that the condition of the boiler water requiring evaluation has reached Example 1, since silica concentration is one of the water quality items along with electrical conductivity and pH, the water quality evaluation program determines in step S6 that there is a water quality item requiring dilution of the sample water (primary test water), assigns the second analyzer 320 on the upstream side to pH measurement, and assigns the third analyzer 330 on the downstream side to silica concentration measurement, and sets the second analyzer 320 and the third analyzer 330 for pH measurement and silica concentration measurement, respectively. Specifically, the second analyzer 320 selects a sensor for pH measurement from a group of multiple pairs of sensors and selects a reagent for pH measurement from the reagent supply device 140 as a color-developing reagent to be added to the cell, and the third analysis unit 330 selects a sensor for silica concentration measurement from a group of multiple pairs of sensors and selects a reagent for silica concentration measurement from the reagent supply device 140 as a color-developing reagent to be added to the cell.

[0051] If it is determined in step S4 that the condition of the boiler water requiring evaluation has reached Example 2, then, since the water quality items other than electrical conductivity are chloride ion concentration and silica concentration, in step S6 the water quality evaluation program determines that dilution of the sample water (primary test water) is required to measure all remaining water quality items other than electrical conductivity measured in analysis step 1. Then, for example, the second analyzer 320 on the upstream side is assigned to measure chloride ion concentration, and the third analyzer 330 on the downstream side is assigned to measure silica concentration, with the second analyzer 320 and the third analyzer 330 set to measure chloride ion concentration and silica concentration, respectively. Specifically, the second analyzer 320 selects a sensor for measuring chloride ion concentration from a group of multiple pairs of sensors and also selects a reagent for measuring chloride ion concentration as a color-developing reagent to be added to the cell from the reagent supply device 140, and the third analysis unit 330 selects a sensor for measuring silica concentration from a group of multiple pairs of sensors and also selects a reagent for measuring silica concentration as a color-developing reagent to be added to the cell from the reagent supply device 140. In Example 2, the allocation of water quality items to the second analyzer 320 and the third analyzer 330 may be reversed.

[0052] Furthermore, if it is determined in step S4 that the boiler water condition requiring evaluation has reached Example 3, since hardness and iron concentration are included as water quality items in addition to electrical conductivity, the water quality evaluation program determines in step S6 that dilution of the sample water (primary water test) is unnecessary for measuring water quality items other than electrical conductivity measured in analysis step 1. Then, for example, the second analyzer 320 on the upstream side is assigned to measure hardness, and the third analyzer 330 on the downstream side is assigned to measure iron concentration, and the second analyzer 320 and the third analyzer 330 are set to measure hardness and iron concentration, respectively. Specifically, the second analyzer 320 selects a sensor for hardness measurement from a group of multiple pairs of sensors and selects a reagent for hardness measurement from the reagent supply device 140 as a color-developing reagent to be added to the cell. Furthermore, the third analysis unit 330 selects a sensor for iron concentration measurement from a group of multiple pairs of sensors and selects a reagent for iron concentration measurement from the reagent supply device 140 as a color-developing reagent to be added to the cell. In Example 3, the allocation of water quality items to the second analyzer 320 and the third analyzer 330 may also be reversed.

[0053] If it is determined in step S4 that the boiler water condition requiring evaluation has reached Example 4, then, since pH and tracer substance concentration are included as water quality items in addition to electrical conductivity, in step S6 the water quality evaluation program determines, as in Example 3, that dilution of the sample water (primary test water) is not required for measuring water quality items other than electrical conductivity measured in analysis step 1. Then, the second analyzer 320 or the third analyzer 330, which is a colorimeter, is assigned and set for pH measurement, and the fourth analyzer 340, which is a fluorometer, is assigned for measuring the tracer substance concentration. In setting the second analyzer 320 or the third analyzer 330, a sensor for pH measurement is selected from a group of multiple sensor pairs, and a reagent for pH measurement is selected as the color-developing reagent to be added to the cell from the reagent supply device 140.

[0054] After step S6 is completed, the water quality evaluation program proceeds to step S7, where it determines whether dilution of the sample water (primary test water) is necessary for measuring all water quality items other than electrical conductivity, based on the settings made in step S6.

[0055] If it is determined in step S4 that Example 1 has been reached, dilution of the water sample (primary water sample) is not necessary for pH measurement, and the water quality evaluation program proceeds from step S7 to step S8, where analysis step 2 is executed. That is, the pH of the water sample (primary water sample) is measured by the second analyzer 320. Here, the second inlet valve 321 is opened and the pump 251 is operated to introduce the water sample (primary water sample) from the water storage tank 240 into the cell of the second analyzer 320 through the water supply path 250. Then, the pump 251 is stopped and the second inlet valve 321 is closed, after which the second analyzer 320 is operated to measure the pH of the water sample (primary water sample). At an appropriate time after the pH measurement, the water sample in the cell is discharged through the second waste water path 322.

[0056] After the analysis step 2 is completed, the water quality evaluation program proceeds to step S9, where it determines whether the sample water (primary test water) stored in the water storage tank 240 needs to be diluted in the next measurement by the third analyzer 330, based on the setting in step S6. Here, since the third analyzer 330 is assigned to measure silica concentration, the water quality evaluation program proceeds to step S11, where it executes a dilution step for the sample water (primary test water). In this dilution step, the fifth on-off valve 266 is opened while the first on-off valve 213 is kept open, and cooling water from the introduction path 212 is supplied as dilution water to the main path 261 of the supply path 260. The dilution water supplied to the main path 261 is purified by passing through the activated carbon filter 263 and the ion exchange resin filter 264 in this order, and then flows into the metering tank 265. Here, dilution water that flows into the metering tank 265 above a predetermined water level overflows into the second overflow path 267. As a result, a predetermined amount of dilution water is stored in the measuring tank 265.

[0057] Next, in the water tank 240, the third on-off valve 245 is opened, and a portion of the boiler water is discharged from the water tank 240 through the water volume adjustment path 243. This lowers the water level of the sample water (primary test water) in the water tank 240, and the amount of sample water (primary test water) remaining in the water tank 240 is adjusted. Subsequently, the sixth on-off valve 269 is opened, and the entire amount of dilution water is supplied from the metering tank 265 to the water tank 240 through the communication path 268. This causes the sample water (primary test water) in the water tank 240 to be diluted with the dilution water and prepared as sample water (secondary test water) suitable for measuring the silica concentration in the third analyzer 330. At this time, the remaining amount of the sample water (primary test water) in the water tank 240 is adjusted to a predetermined amount by the water volume adjustment path 243, and the sample water is diluted by supplying a predetermined amount of dilution water stored in the metering tank 265, thereby achieving highly accurate control to a desired dilution ratio. Furthermore, when diluting to a required ratio, the amount of sample water (primary test water) in the water storage tank 240 is reduced and then diluted with dilution water, thereby reducing the amount of dilution water used.

[0058] The water sample (secondary water sample) prepared by diluting the water sample (primary water sample) in the water storage tank 240 is circulated through the circulation path 252 by reopening the fourth open valve 253 and operating the pump 251, whereby the water sample is stirred and homogenized. This reduces the effects of measurement errors and the like caused by diluting the water sample (primary water sample), and improves the accuracy of the water quality evaluation (here, the accuracy of measuring the silica concentration). Once the dilution of the water sample (primary water sample) is complete, the water quality evaluation program proceeds to step S10, where analysis step 3 is executed. That is, the silica concentration of the water sample (secondary water sample) is measured by the third analyzer 330.

[0059] Here, the third inlet valve 331 is opened and the pump 251 is operated to introduce the sample water (secondary test water) from the water storage tank 240 through the water supply path 250 into the cell of the third analyzer 330. Then, the pump 251 is stopped and the third inlet valve 331 is closed, after which the third analyzer 330 is operated to measure the silica concentration of the sample water (secondary test water). The silica concentration of the collected boiler water is calculated based on the silica concentration measured for the sample water (secondary test water) and the dilution ratio of the sample water (primary test water). At an appropriate time after measuring the silica concentration, the sample water in the cell is discharged through the third waste water path 332.

[0060] If it is determined in step S4 that Example 2 has been reached, dilution of the water sample (primary water sample) is necessary for both chloride ion concentration measurement and silica concentration measurement. Therefore, the water quality evaluation program proceeds from step S7 to step S12, where the water sample (primary water sample) dilution process is performed in the same manner as in step S11. The water quality evaluation program then proceeds to step S13, where analysis process 2 is performed, i.e., the process of measuring the chloride ion concentration of the water sample (secondary water sample) using the second analyzer 320. The operation here is the same as step S8, except that the water sample (secondary water sample) introduced from the water storage tank 240 into the cell of the second analyzer 320 is the secondary water sample prepared by diluting the primary water sample in step S12, and the selected sensor and color reagent are different. After step S13 is completed, the water quality evaluation program proceeds to step S10, where analysis process 3 is performed, i.e., the process of measuring the silica concentration of the water sample (secondary water sample) using the third analyzer 330. The operation here is the same as that of step S10 described above, except that the sample water introduced into the cell of the third analyzer 330 is the secondary water sample, as in step S13.

[0061] If it is determined in step S4 that Example 3 or Example 4 has been reached, dilution of the primary water sample is not required for measuring any of the water quality items. Therefore, the water quality evaluation program proceeds from step S7 to step S8, and then from step S9 to step S10. By sequentially supplying the primary water sample to the specified analyzers according to the settings in step S6, analysis steps 2 and 3 for the specified water quality items are performed. In analysis step 3 of Example 4, the fourth inlet valve 341 is opened and the pump 251 is operated to introduce the water sample (primary water sample) from the water storage tank 240 through the water supply path 250 into the cell of the fourth analyzer 340. Then, the pump 251 is stopped and the fourth inlet valve 341 is closed, after which the fourth analyzer 340 is operated to measure the tracer concentration of the water sample (primary water sample). At an appropriate time after measuring the tracer concentration, the water sample in the cell is discharged through the fourth wastewater channel 342.

[0062] The operation program of the boiler apparatus 1 adjusts the quality of the boiler water by controlling the amount of water treatment agent added to the feedwater from the chemical supply device 140 and the amount of boiler water blown from the boiler body 120 in light of the water quality of the sample water evaluated by the water quality evaluation program. In this embodiment, the degree of concentration of the boiler water is used as a criterion for judging the operating status of the boiler body 120, and the timing of boiler water sampling is determined in light of this criterion. Therefore, the water quality evaluation by the water quality evaluation program reflects the condition of the sample water, i.e., the management status of the boiler water, and is highly useful as an index for adjusting the water quality of the boiler water. The water quality adjustment of the boiler water based on this water quality evaluation can effectively suppress the progression of corrosion and scale formation and is highly timely.

[0063] After the end of analysis step 3 in step S10 and while the boiler body 120 is operating, the water quality evaluation program returns to step S4 to determine whether the degree of concentration of the boiler water has reached any of examples 1 to 4. When the degree of concentration has reached any of examples 1 to 4, the water quality evaluation program repeats step S5 and subsequent steps to evaluate the water quality items of the corresponding example.

[0064] The water quality items of boiler water evaluated in water quality evaluation system 20 at each stage of the boiler water sampling period are not measured on boiler water sampled individually from boiler body 120 with a time lag for each evaluation, but on sample water (primary test water or secondary test water) allocated from boiler water sampled all at once without time lag from boiler body 120, so the results accurately reflect each water quality item at the time the boiler water was sampled and are highly reliable. Furthermore, because multiple items are selected as the water quality items to be evaluated rather than simply one, the management status of the target boiler water can be comprehensively assessed from the perspective of, for example, whether the concentrations of water treatment agents and corrosion-suppressing components are appropriate relative to the concentration of corrosion-promoting components, or whether excessive concentration is likely to promote the precipitation of scale components, enabling more precise water quality adjustment. Therefore, the boiler apparatus 1 equipped with the water quality evaluation system 20 is particularly effective in water quality management to suppress scale and corrosion in the multi-tube once-through boiler, when the boiler section 10 is a multi-tube once-through boiler (a special circulation boiler defined by the Japanese Industrial Standards (JIS)) in which the water quality of the boiler water fluctuates significantly.

[0065] In the boiler apparatus 1 described above, the boiler water quality evaluation system 20 can be modified in various ways, for example, as follows.

[0066] (1) In the above-described embodiment, the degree of concentration of the boiler water is used as a criterion for determining the operating status of the boiler body 120. However, the criterion for determining the operating status may be a criterion that combines the degree of concentration with other factors that may affect corrosion or scale formation in the boiler body 120, or may be a criterion different from the degree of concentration.

[0067] As another factor that may be combined with the degree of concentration, for example, fluctuations in the quality of the raw water can be referenced. The quality of the raw water can then be evaluated by the water quality evaluation system 20. In evaluating the quality of the raw water by the water quality evaluation system 20, the first on-off valve 213 of the supply path 260 is opened and the seventh on-off valve 270 of the sub-path 262 is opened. As a result, the raw water to be used as cooling water flows into the sub-path 262 of the supply path 260 and is supplied to the water storage tank 240. The raw water stored in the water storage tank 240 is then sent to the analysis unit 300, where its quality is evaluated. Fluctuations in the quality of the raw water can be monitored by appropriately repeating the evaluation of the quality of the raw water in parallel with monitoring the degree of concentration.

[0068] On the other hand, examples of criteria for judgment other than the concentration progress degree include the operating mode of the boiler body 120, the circulation state of the boiler water in the boiler body 120, or the water quality state of the feedwater replenished to the boiler body 120. These criteria may be used individually or in combination in place of the concentration progress degree, or may be used individually or in combination in conjunction with the concentration progress degree.

[0069] The operating mode of the boiler body 120 can refer to the operating pattern set based on the operating pressure and combustion amount inside the boiler body 120, and the status of alarms issued for operational anomalies in the boiler body 120. For example, by sampling boiler water every time the boiler body 120 enters a specific operating pattern and evaluating the water quality, such as its electrical conductivity, pH, and chloride ion concentration, it is possible to continuously predict the water quality trend inside the boiler body 120 for each operating pattern. In light of this standard, it is possible to evaluate the possibility of corrosion and scale formation in the boiler body 120 and optimize the operating state of the boiler body 120.

[0070] The boiler water circulation state in the boiler body 120 fluctuates due to the influence of the feedwater supplied to the lower header of the boiler body 120, which can cause corrosion by lowering the pH of the boiler water and increasing the dissolved oxygen concentration. The boiler water circulation state can be evaluated, for example, based on the operation signal of the feedwater pump in the feedwater path 131 and the temperature of the lower header of the boiler body 120, and by evaluating the pH, dissolved oxygen, etc. of boiler water sampled at a water sampling time determined based on this evaluation, the tendency for corrosion to occur in the boiler body 120 can be grasped.

[0071] The water quality status of the feedwater supplied to the boiler body 120 can be referenced to the occurrence of alarms for operational abnormalities in the water supply device 130, such as hardness leakage or insufficient injection of water treatment agents. For example, by sampling boiler water when an alarm is issued and evaluating the water quality for items related to each alarm (hardness in the case of a hardness leakage alarm, pH or tracer substance concentration in the case of an insufficient injection alarm of water treatment agents), it is possible to grasp the tendency for corrosion and scale formation in the boiler body 120 in real time.

[0072] (2) In the water quality evaluation system 20 according to the above-described embodiment, the boiler water treatment unit 200 prepares sample water for the second analyzer 320, the third analyzer 330, or the fourth analyzer 340, respectively, and supplies the sample water to the second analyzer 320, the third analyzer 330, and the fourth analyzer 340 individually. However, if diluted sample water (secondary test water) is not required, the prepared sample water (primary test water) can be modified to be supplied serially and in turn from the water storage tank 240 to the second analyzer 320, the third analyzer 330, and the fourth analyzer 340 in that order.

[0073] In this case, as shown in Figure 6, the water supply path 250 extending from the water tank 240 is connected in series in this order to the second analyzer 320, the third analyzer 330, and the fourth analyzer 340, with the second inlet valve 321, the third inlet valve 331, and the fourth inlet valve 341 provided on the inlet side, respectively, and the discharge side of the fourth analyzer 340 is connected to the discharge path 214.

[0074] In this modification, the pump 251 is operated while the second inlet valve 321, the third inlet valve 331, and the fourth inlet valve 341 are opened and closed in sequence, and the sample water in the water storage tank 240 is supplied in turn to the second analyzer 320, the third analyzer 330, and the fourth analyzer 340 through the water supply path 250. As a result, the sample water has predetermined water quality items measured in sequence in the second analyzer 320, the third analyzer 330, and the fourth analyzer 340, and then flows from the fourth analyzer 340 to the discharge path 214 and is discarded.

[0075] 7, in the analyzing unit 300 of the above-described embodiment and modified example, a dedicated path 350 for measuring water quality items that do not require diluted water sample (secondary water test) can be provided in addition to the second analyzer 320, the third analyzer 330, and the fourth analyzer 340. This dedicated path 350 branches off from the water supply path 250 at a position downstream of the circulation path 252 and includes three dedicated analyzers 320a, 330a, and 340a arranged in series. The dedicated path 350 also has an inlet valve 351 upstream of the dedicated branch 320a. When the inlet valve 351 is opened and the pump 251 is operated, the water sample (primary water test) stored in the water storage tank 240 is supplied to the dedicated path 350. The water sample (primary water test) flows continuously through the dedicated analyzers 320a, 330a, and 340a in this order, and predetermined water quality items are measured in each of the dedicated analyzers 320a, 330a, and 340a.

[0076] (3) As shown in FIG. 8, the boiler section 10 of the boiler device 1 may be a boiler group having a plurality of boiler units, for example, three boiler bodies 120a, 120b, and 120c, and these boiler bodies 120a, 120b, and 120c may be operated simultaneously or appropriately selected to supply steam to the load device 110 through the steam supply pipe 123.

[0077] When the boiler section 10 has such a configuration, the water supply device 130 has water supply paths 131a, 131b, and 131c that connect to the boiler bodies 120a, 120b, and 120c, respectively, and each of the water supply paths 131a, 131b, and 131c has an individual water supply pump (not shown) for sending the water supply stored in a water supply tank to the corresponding boiler body 120a, 120b, and 120c. Also, each of the water supply paths 131a, 131b, and 131c has an individual chemical supply device 140a, 140b, and 140c for adding a water treatment agent to the water supply supplied to the corresponding boiler body 120a, 120b, and 120c, respectively.

[0078] In addition, in this boiler section 10, the boiler bodies 120a, 120b and 120c have blow paths 121a, 121b and 121c, respectively, and each blow path 121a, 121b and 121c has a first control valve 141a, 141b and 141c, respectively, for adjusting the amount of boiler water discharged from the corresponding boiler bodies 120a, 120b and 120c.

[0079] In the boiler apparatus 1 equipped with this boiler section 10, the sampling path 210 of the water quality evaluation system 20 branches into three branches in the boiler section 10, and each branch path is provided with a second control valve 211a, 211b, and 211c, respectively, and is connected individually to each of the boiler bodies 120a, 120b, and 120c. This allows the water quality evaluation system 20 to sample boiler water individually from the boiler bodies 120a, 120b, and 120c.

[0080] In this modification, the judgment unit 400 of the water quality evaluation system 20 individually monitors the operating status of each of the boiler bodies 120a, 120b, and 120c, and individually judges the time to collect boiler water for each of the boiler bodies 120a, 120b, and 120c. Then, the boiler body 120a, 120b, or 120c that is judged to have reached the time to collect boiler water is selected as the boiler water collection target. Then, by controlling the corresponding second control valve 211a, 211b, or 211c of the selected boiler body 120a, 120b, or 120c, a portion of the boiler water is collected to prepare sample water, and the water quality is evaluated. The operating program of the boiler apparatus 1 controls the amount of boiler water blown from the boiler body 120a, 120b or 120c from which the boiler water was collected, and the amount of required water treatment agent added to the supply water from the corresponding chemical supply device 140a, 140b or 140c, in accordance with the evaluated water quality of the sample water, thereby controlling the water quality of the boiler water in the target boiler body 120a, 120b or 120c.

[0081] (4) In the above-described embodiment, the analysis unit 300 of the water quality evaluation system 20 includes a first analyzer 310, which is a sensor for measuring electrical conductivity to measure required water quality items, two colorimeters, namely, a second analyzer 320 and a third analyzer 330, and a fourth analyzer 340, which is a fluorometer, but the number of analyzers can be increased or decreased in advance depending on the condition of the boiler water that needs to be evaluated and the number of water quality items that need to be evaluated. The condition of the boiler water that needs to be evaluated varies depending on conditions such as the structure and operating load of the boiler unit 10, and the water quality items to be evaluated accordingly are also examined in advance from a technical perspective and appropriately determined accordingly. For example, in the case of a once-through boiler, which has a relatively small water retention volume relative to the amount of evaporation and whose boiler water quality is prone to extreme fluctuations depending on the boiler's operating conditions, it is necessary to pay close attention to the concentration of corrosion-promoting components and scale components in a highly concentrated state, but in the case of a furnace boiler or water tube boiler, which has a large water retention volume and whose boiler water quality is likely to be stable, it is also possible to manage the concentration of water treatment agents so that it remains within a certain range at a normal concentration. Also, in the case of a boiler with a low operating load, the boiler water remains in a state where it is relatively difficult to concentrate, so it is possible to prioritize evaluation of water quality items such as pH and silica in order to suppress the progression of corrosion in an unconcentrated state.

[0082] Furthermore, the second analyzer 320 and the third analyzer 330 used in the above-described embodiments each have multiple pairs of sensors arranged in the cell corresponding to the measurement items so as to be capable of handling multiple measurement items, and are connected to a reagent supply device that can select and add a color-developing reagent corresponding to the measurement item to the sample water stored in the cell. However, in the analysis unit 300, an analyzer may be provided corresponding to each measurement item. In other words, the analysis unit 300 may be equipped with analyzers for the number of water quality items that need to be measured. In this case, according to Examples 1 to 4 shown in Table 1, six analyzers would be installed in addition to the first analyzer 310 for measuring electrical conductivity.

[0083] Furthermore, in the above-described embodiment, since the water quality items evaluated in Example 4 include tracer substance concentration, a fourth analyzer 340, which is a fluorometer for measuring the tracer substance concentration, is installed in the analysis unit 300. However, if a colorimeter that can also be used as a fluorometer is available, the fourth analyzer 340 can be omitted by using such a colorimeter as the second analyzer 320 or the third analyzer 330.

[0084] (5) In the above-described embodiment, a sensor for measuring electrical conductivity is used as the first analyzer 310 in the water tank 240, which measures the electrical conductivity of the boiler water and detects the water level of the boiler water in the water tank 240. However, the water level of the boiler water may also be detected by a water level sensor provided separately from the electrical conductivity sensor used as the first analyzer 310, such as a float-type, electrode-type, or laser-type level sensor.

[0085] (6) In the above-described embodiment, purified water passed through activated carbon filter 263 and ion exchange resin filter 264 is used as the dilution water supplied from dilution water supply path 260 to metering tank 265. However, if the water quality standards required for dilution water are met, activated carbon filter 263 and ion exchange resin filter 264 may be omitted from main path 261. In this case, raw water used as cooling water or softened water obtained by removing hardness components from raw water is used as the dilution water sent from supply path 260 to metering tank 265.

[0086] (7) In the above embodiment, the second analyzer 320 and the third analyzer 330 of the analysis unit 300 are colorimeters, but depending on the water quality items to be evaluated, electrode-type water quality meters can also be used as these analyzers.

[0087] (8) In the above-described embodiment, the results of evaluation by the water quality evaluation system 20 can be used as data for the manager or maintenance service personnel of the boiler equipment 1 to make adjustments such as adding water treatment agents on-site, and the boiler equipment 1 can also be controlled thereby.

[0088] This disclosure will contribute to the safe and efficient operation of boilers and the stable supply of heat through the evaluation of boiler water quality, and may therefore contribute to the realization of Goal 7 of the United Nations-led Sustainable Development Goals (SDGs), "Affordable and clean energy." [Explanation of symbols]

[0089] 10 Boiler section 20 Water Quality Assessment System 120, 120a, 120b, 120c Boiler body 200 Boiler water treatment section 300 Analysis Department 310 1st Analyzer 320 Second analyzer 330 Third analyzer 340 4th Analyzer 400 Judgment Department

Claims

1. A boiler water quality evaluation system for an operating boiler, comprising: a determination unit that determines a time to collect the boiler water from the boiler based on an operating condition of the boiler; an analysis unit for evaluating the water quality of the boiler water; Equipped with The analysis unit includes a boiler water processing unit that collects the boiler water from the boiler at a time determined by the determination unit and prepares sample water for evaluating the water quality of the boiler water, and evaluates the water quality of the boiler water using the sample water. Boiler water quality evaluation system.

2. the analysis unit includes a plurality of analyzers for evaluating a plurality of water quality items of the boiler water; The boiler water processing unit prepares the sample water to be supplied to the plurality of analyzers using the boiler water collected at the time determined by the determination unit. The boiler water quality evaluation system according to claim 1 .

3. The boiler water quality evaluation system according to claim 2 , wherein the boiler water processing unit prepares the sample water for each of the plurality of analyzers.

4. A water quality evaluation system for boiler water as described in any one of claims 1 to 3, wherein the sample water prepared by the boiler water treatment unit is a primary test water obtained by cooling the collected boiler water or a secondary test water obtained by diluting the primary test water.

5. The boiler is a boiler group consisting of a plurality of boiler units, The determination unit selects a boiler unit from the boiler group as a target from which boiler water is to be collected by the boiler water processing unit based on the operating status of each of the boilers. The boiler water quality evaluation system according to claim 1 .

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