An on-line total iron analyzer suitable for use in the start-up phase chemical supervision

Abstract

This disclosure provides an online total iron analyzer suitable for chemical monitoring during startup, comprising: a sample introduction and acidification unit for introducing and acidifying a water sample; a digestion unit connected to the sample introduction and acidification unit for receiving the acidified water sample and digesting the ferrous ions therein into ferric ions; a reaction and colorimetric unit connected to the digestion unit for performing a complexation colorimetric reaction between the digested water sample and a colorimetric reagent under alkaline conditions in a reaction tank to generate a complex with characteristic absorption; a detection unit connected to the reaction and colorimetric unit for measuring the absorbance of the colorimetric sample at a specific wavelength; and a control and processing unit connected to the sample introduction and acidification unit, the digestion unit, the reaction and colorimetric unit, and the detection unit, for controlling the operation of the sample introduction and acidification unit, the digestion unit, the reaction and colorimetric unit, and the detection unit, and calculating the total iron content in the water sample based on the absorbance value.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of power plant chemical online monitoring and supervision technology, specifically relating to an online total iron analyzer suitable for chemical supervision during the start-up phase. Background Technology

[0002] During startup, it is necessary to monitor the iron content, conductivity, and pH value of feedwater, boiler water, and condensate to determine the progress of cold and hot water flushing and to identify the appropriate timing for its termination. Traditional manual sampling and testing methods are slow, time-consuming, and labor-intensive, resulting in significant delays in operators' assessment of water quality compliance. This not only wastes a large amount of high-quality demineralized water but may also affect the safe startup of the unit. Among the various chemical indicators that need to be monitored, iron determination is particularly time-consuming.

[0003] Therefore, there is an urgent need to develop an online total iron analyzer suitable for chemical monitoring during the start-up phase, in order to shorten the detection time and improve the timeliness and accuracy of monitoring. Summary of the Invention

[0004] The embodiments disclosed herein aim to at least address one of the technical problems existing in the prior art, and provide an online total iron analyzer suitable for chemical monitoring during startup.

[0005] One aspect of the embodiments of this disclosure provides an online total iron analyzer suitable for chemical monitoring during startup, comprising: The sample introduction and acidification unit is used to introduce water samples and acidify them. The digestion unit, connected to the sample injection and acidification unit, is used to receive the acidified water sample and digest the ferrous ions therein into ferric ions. The reaction and colorimetric unit is connected to the digestion unit and is used to perform a complexation and colorimetric reaction between the digested water sample and the colorimetric agent under alkaline conditions in the reaction tank to generate a complex with characteristic absorption. The detection unit, connected to the reaction and color development unit, is used to measure the absorbance of the sample after color development at a specific wavelength. The control and processing unit is connected to the sample injection and acidification unit, the digestion unit, the reaction and color development unit, and the detection unit, respectively, and is used to control the operation of the sample injection and acidification unit, the digestion unit, the reaction and color development unit, and the detection unit, and to calculate the total iron content in the water sample based on the absorbance value.

[0006] Optionally, the reaction and color development unit includes a reaction tank and a color development agent dosing module and an alkaline regulator dosing module respectively connected to the reaction tank.

[0007] Optionally, the colorimetric reagent dosing module includes a sulfosalicylic acid solution tank connected to the reaction tank, and a sulfosalicylic acid solution metering pump disposed in the pipeline between the sulfosalicylic acid solution tank and the reaction tank. The alkaline regulator dosing module includes a concentrated ammonia tank connected to the reaction tank, and a concentrated ammonia metering pump installed in the pipeline between the concentrated ammonia tank and the reaction tank.

[0008] Optionally, the reaction and color development unit further includes a pH meter and a liquid level sensor disposed within the reaction tank; The control and processing unit controls the start and stop of the alkaline regulator dosing module based on the feedback signal from the pH meter.

[0009] Optionally, the reaction and color development unit further includes a stirring magnetic element disposed within the reaction tank.

[0010] Optionally, the reaction and color development unit further includes a deionized water filling module, which includes a deionized water tank and a first deionized water pump connected to the deionized water tank. The outlet of the first deionized water pump is connected to the reaction tank. The control and processing unit controls the start and stop of the first deionized water pump according to the feedback signal from the liquid level sensor.

[0011] Optionally, the sample injection and acidification unit includes: a water sample tube connected to the digestion unit, a first valve disposed on the water sample tube, a concentrated hydrochloric acid tank connected to the water sample tube, a concentrated hydrochloric acid metering pump connected to the pipeline between the water sample tube and the concentrated hydrochloric acid tank, and a reaction coil disposed at the junction of the first valve and the concentrated hydrochloric acid metering pump, wherein the outlet of the reaction coil is connected to the digestion unit.

[0012] Furthermore, it also includes a cleaning unit, which includes: a second deionized water pump disposed in the pipeline between the deionized water tank and the water sample tube, a first discharge pump on the bypass connected to the inlet pipeline of the detection unit, and a second discharge pump disposed in the outlet pipeline of the detection unit; The control and processing unit flushes the water sample tube, the reaction tank, and / or the detection unit by controlling the start and stop of the second deionized water pump, the first discharge pump, and the second discharge pump.

[0013] Furthermore, it also includes: a first delivery pump disposed in the pipeline between the digestion unit and the inlet of the reaction tank, and a second delivery pump disposed in the pipeline between the outlet of the reaction tank and the detection unit.

[0014] The beneficial effects of the embodiments of this disclosure include: This application achieves rapid, continuous, and online monitoring of total iron content in water during the power plant startup phase through a fully automated control design: acidification of the water sample by the sample introduction and acidification unit, microwave digestion of the acidified water sample by the digestion unit, automatic dosing and pH adjustment by the reaction and colorimetric unit, photometric detection by the detection unit, and control and processing unit. The analyzer in this application can replace traditional time-consuming manual testing, significantly improving detection timeliness and accuracy, enabling operators to judge the water flushing process in real time and accurately determine the flushing endpoint. Furthermore, the analyzer not only saves a large amount of high-quality demineralized water and shortens unit startup time, but also provides strong support for the safe startup and stable operation of the unit through timely and reliable chemical monitoring. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an online total iron analyzer suitable for chemical monitoring during startup, according to an embodiment of this disclosure.

[0016] 1. First valve; 2. Concentrated hydrochloric acid metering pump; 3. Concentrated hydrochloric acid tank; 4. Reaction coil; 5. Digestion unit; 6. First transfer pump; 7. pH meter; 8. Stirring magnet; 9. Reaction tank; 10. Liquid level sensor; 11. Sulfosalicylic acid solution tank; 12. Sulfosalicylic acid solution metering pump; 13. Concentrated ammonia tank; 14. Concentrated ammonia metering pump; 15. Deionized water tank; 16. First deionized water pump; 17. Second deionized water pump; 18. Second transfer pump; 19. Detection unit; 20. First discharge pump; 21. Second discharge pump; 22. Water sample tube. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed descriptions and accompanying drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0019] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0020] like Figure 1 As shown, an online total iron analyzer suitable for chemical monitoring during startup includes a sample introduction and acidification unit, a digestion unit 5, a reaction and colorimetric unit, a detection unit 19, and a control and processing unit.

[0021] The sample introduction and acidification unit is used to introduce water samples and acidify them. The digestion unit 5 is connected to the sample introduction and acidification unit and is used to receive the acidified water sample and digest the ferrous ions in it into ferric ions.

[0022] The reaction and color development unit is connected to the digestion unit 5 and is used to perform a complexation and color development reaction between the digested water sample and the color development agent under alkaline conditions in the reaction tank 9 to generate a complex with characteristic absorption.

[0023] The detection unit 19 is connected to the reaction and color development unit and is used to measure the absorbance of the sample after color development at a specific wavelength.

[0024] The control and processing unit is connected to the sample injection and acidification unit, the digestion unit 5, the reaction and color development unit and the detection unit 19 respectively, and is used to control the operation of the sample injection and acidification unit, the digestion unit 5, the reaction and color development unit and the detection unit 19, and calculate the total iron content in the water sample based on the absorbance value.

[0025] This application achieves rapid, continuous, and online monitoring of total iron content in water during the power plant startup phase through a fully automated control design: acidification of the water sample by the sample introduction and acidification unit, microwave digestion of the acidified water sample by the digestion unit 5, automatic dosing and pH adjustment by the reaction and color development unit, photometric detection by the detection unit 19, and control and processing unit. The analyzer in this application can replace traditional time-consuming manual testing, significantly improving detection timeliness and accuracy, enabling operators to judge the water flushing process in real time and accurately determine the flushing endpoint. Furthermore, the analyzer not only saves a large amount of high-quality demineralized water and shortens unit startup time, but also provides strong support for the safe startup and stable operation of the unit through timely and reliable chemical monitoring.

[0026] In some embodiments, the digestion unit 5 includes a microwave digestion module, and the detection unit 19 includes a detection cell.

[0027] In some embodiments, the reaction and color development unit includes a reaction tank 9 and a color development agent dosing module and an alkaline regulator dosing module respectively connected to the reaction tank 9.

[0028] In this application, the reaction and color development unit adopts an integrated colorimetric reagent dosing module and an alkaline regulator dosing module, realizing a precise and automatic complexation color development design of iron ions and reagents in water samples.

[0029] In some embodiments, the colorimetric reagent dosing module includes a sulfosalicylic acid solution tank 11 connected to the reaction tank 9, and a sulfosalicylic acid solution metering pump 12 disposed in a pipeline between the sulfosalicylic acid solution tank 11 and the reaction tank 9.

[0030] The alkaline regulator dosing module includes a concentrated ammonia tank 13 connected to the reaction tank 9, and a concentrated ammonia metering pump 14 installed in the pipeline between the concentrated ammonia tank 13 and the reaction tank 9.

[0031] In this application, both the colorimetric reagent dosing module and the alkaline regulator dosing module adopt independent reagent tanks and metering pump combinations, which realizes the precise and quantitative addition of sulfosalicylic acid and concentrated ammonia, thereby ensuring the stability of the colorimetric reaction conditions and the reproducibility of the results.

[0032] In some embodiments, the reaction and color development unit further includes a pH meter 7 and a liquid level sensor 10 disposed within the reaction tank 9.

[0033] The control and processing unit controls the start and stop of the alkaline regulator dosing module based on the feedback signal from the pH meter 7.

[0034] In this application, by setting up a pH meter 7, real-time monitoring and closed-loop control can be achieved using the control and processing unit, realizing precise and automatic adjustment of the pH value of the reaction system, and ensuring that the colorimetric reaction proceeds stably under optimal alkaline conditions.

[0035] In some embodiments, the reaction and color development unit further includes a stirring magnet 8 disposed within the reaction tank 9.

[0036] In this application, the use of the stirring magnet 8 can ensure that the liquid in the reaction tank 9 is fully and uniformly mixed, thereby accelerating the reaction process and ensuring the uniformity of color development and pH adjustment.

[0037] In some embodiments, the reaction and color development unit further includes a deionized water dispensing module, which includes a deionized water tank 15 and a first deionized water pump 16 connected to the deionized water tank 15. The outlet of the first deionized water pump 16 is connected to the reaction tank 9. The control and processing unit controls the start and stop of the first deionized water pump 16 based on the feedback signal from the liquid level sensor 10.

[0038] In this application, the control and processing unit can realize closed-loop control of deionized water addition through the feedback signal of the liquid level sensor 10, and realize automatic and precise dilution and volume adjustment of the colorimetric solution in the reaction tank 9, ensuring the comparability of detection optical path and concentration between different samples, and improving the accuracy and repeatability of measurement.

[0039] In some embodiments, the sample injection and acidification unit includes a water sample tube 22 connected to the digestion unit 5, a first valve 1 disposed on the water sample tube 22, a concentrated hydrochloric acid tank 3 connected to the water sample tube 22, a concentrated hydrochloric acid metering pump 2 connected to the pipeline between the water sample tube 22 and the concentrated hydrochloric acid tank 3, and a reaction coil 4 disposed at the junction of the first valve 1 and the concentrated hydrochloric acid metering pump 2, wherein the outlet of the reaction coil 4 is connected to the digestion unit 5.

[0040] In this application, the sample introduction and acidification unit adopts a structured design of valves, metering pumps and reaction coil 4, which realizes the controlled introduction of water sample and the precise, online acidification and mixing design of acid, and can provide a stable and uniform acidic pretreated water sample for subsequent microwave digestion.

[0041] In some embodiments, a cleaning unit is also included, which includes a second deionized water pump 17 disposed in the pipeline between the deionized water tank 15 and the water sample tube 22, a first discharge pump 20 on the bypass 23 connected to the inlet pipeline of the detection unit 19, and a second discharge pump 21 disposed in the outlet pipeline of the detection unit 19.

[0042] The control and processing unit flushes the water sample tube 22, the reaction tank 9, and / or the detection unit 19 by controlling the start and stop of the second deionized water pump 17, the first discharge pump 20, and the second discharge pump 21.

[0043] In this application, an integrated combination of water pump and discharge pump is used to achieve automatic and efficient flushing of key pipelines and containers through which water samples flow, effectively preventing sample residue and cross-contamination, and ensuring the accuracy of continuous online measurement.

[0044] In some embodiments, the analyzer further includes a first delivery pump 6 disposed in a pipeline between the digestion unit 5 and the inlet of the reaction tank 9, and a second delivery pump 18 disposed in a pipeline between the outlet of the reaction tank 9 and the detection unit 19.

[0045] In this application, by setting up a first delivery pump 6 and a second delivery pump 18, the precise and quantitative transfer of samples between digestion, color development and detection stages is achieved, ensuring the automation of the process and the smooth connection between each step.

[0046] Specifically, when a sample needs to be tested, the first valve 1 and the concentrated hydrochloric acid metering pump 2 are opened. The water sample is mixed evenly with a certain amount of concentrated hydrochloric acid in the reaction chamber 4, and the water sample is acidified. The acidified water sample is then digested in the digestion unit 5, converting the iron in the water sample into ferric ions. The first delivery pump 6 is then opened, and the digested water sample enters the reaction tank 9 through the first delivery pump 6.

[0047] With the stirring of the magnetic stirrer 8, turn on the sulfosalicylic acid solution metering pump 12 and add a certain amount of sulfosalicylic acid to the water sample. Then, turn on the concentrated ammonia metering pump 14 and add a certain amount of concentrated ammonia to the water sample. Use a pH meter to monitor the pH of the water sample. When the pH of the water sample reaches 10±0.5, turn off the concentrated ammonia metering pump 14.

[0048] Turn on the first deionized water pump 16 to add deionized water to the reaction tank 9. Use the level sensor 10 to monitor the liquid level in the reaction tank 9. When the liquid level in the reaction tank 9 reaches the preset value, turn off the first deionized water pump 16. Turn on the second transfer pump 18 to transport the colored water sample to the detection unit 19. Then turn on the first discharge pump 20 to discharge the excess water sample.

[0049] After the test is completed, the second discharge pump 21 is turned on to discharge the water sample. At the same time, the second deionized water pump 17, the first transfer pump 6, and the second transfer pump 18 are turned on to flush the test system. The flushing wastewater is discharged through the first discharge pump 20 and the second discharge pump 21.

[0050] The online total iron analyzer of this application, applicable to chemical monitoring during the start-up phase, can automatically and accurately determine the iron content in water.

[0051] Determination Principle: First, a certain amount of concentrated hydrochloric acid is added to the water sample to prevent the hydrolysis of iron ions into precipitates, while simultaneously converting various forms of iron into free states. The acidified water sample is then digested using a microwave digestion module, converting all ferrous ions in the sample into ferric ions. Subsequently, a colorimetric reagent—sulfosalicylic acid—is added to the water sample. Sulfosalicylic acid initially complexes with iron ions, preventing hydrolysis in subsequent steps. Concentrated ammonia is then added to adjust the pH of the reaction system to the alkaline range (9.0~11.0). Under these conditions, sulfosalicylic acid reacts with ferric ions to form a yellow complex, which exhibits characteristic absorption at a wavelength of 425 nm. By measuring the absorbance of the sample solution and comparing it with an iron standard curve plotted under the same conditions, the iron content in the water sample can be calculated.

[0052] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. An online total iron analyzer suitable for chemical monitoring during startup, characterized in that, include: The sample introduction and acidification unit is used to introduce water samples and acidify them. The digestion unit, connected to the sample injection and acidification unit, is used to receive the acidified water sample and digest the ferrous ions therein into ferric ions. The reaction and colorimetric unit is connected to the digestion unit and is used to perform a complexation and colorimetric reaction between the digested water sample and the colorimetric agent under alkaline conditions in the reaction tank to generate a complex with characteristic absorption. The detection unit, connected to the reaction and color development unit, is used to measure the absorbance of the sample after color development at a specific wavelength. The control and processing unit is connected to the sample injection and acidification unit, the digestion unit, the reaction and color development unit, and the detection unit, respectively, and is used to control the operation of the sample injection and acidification unit, the digestion unit, the reaction and color development unit, and the detection unit, and to calculate the total iron content in the water sample based on the absorbance value.

2. The online total iron analyzer according to claim 1, characterized in that, The reaction and color development unit includes a reaction tank and a color development agent dosing module and an alkaline regulator dosing module, which are respectively connected to the reaction tank.

3. The online total iron analyzer according to claim 2, characterized in that, The colorimetric reagent dosing module includes a sulfosalicylic acid solution tank connected to the reaction tank, and a sulfosalicylic acid solution metering pump installed in the pipeline between the sulfosalicylic acid solution tank and the reaction tank. The alkaline regulator dosing module includes a concentrated ammonia tank connected to the reaction tank, and a concentrated ammonia metering pump installed in the pipeline between the concentrated ammonia tank and the reaction tank.

4. The online total iron analyzer according to claim 2 or 3, characterized in that, The reaction and color development unit also includes a pH meter and a liquid level sensor located in the reaction tank; The control and processing unit controls the start and stop of the alkaline regulator dosing module based on the feedback signal from the pH meter.

5. The online total iron analyzer according to claim 2 or 3, characterized in that, The reaction and color development unit also includes a stirring magnetic element disposed within the reaction tank.

6. The online total iron analyzer according to claim 4, characterized in that, The reaction and color development unit further includes a deionized water filling module, which includes a deionized water tank and a first deionized water pump connected to the deionized water tank. The outlet of the first deionized water pump is connected to the reaction tank. The control and processing unit controls the start and stop of the first deionized water pump according to the feedback signal from the liquid level sensor.

7. The online total iron analyzer according to claim 6, characterized in that, The sample injection and acidification unit includes: a water sample tube connected to the digestion unit, a first valve disposed on the water sample tube, a concentrated hydrochloric acid tank connected to the water sample tube, a concentrated hydrochloric acid metering pump connected to the pipeline between the water sample tube and the concentrated hydrochloric acid tank, and a reaction coil disposed at the junction of the first valve and the concentrated hydrochloric acid metering pump, wherein the outlet of the reaction coil is connected to the digestion unit.

8. The online total iron analyzer according to claim 7, characterized in that, It also includes a cleaning unit, which includes: a second deionized water pump disposed in the pipeline between the deionized water tank and the water sample tube, a first discharge pump on the bypass connected to the inlet pipeline of the detection unit, and a second discharge pump disposed in the outlet pipeline of the detection unit; The control and processing unit flushes the water sample tube, the reaction tank, and / or the detection unit by controlling the start and stop of the second deionized water pump, the first discharge pump, and the second discharge pump.

9. The online total iron analyzer according to claim 2, characterized in that, Also includes: A first delivery pump is installed in the pipeline between the digestion unit and the inlet of the reaction tank, and a second delivery pump is installed in the pipeline between the outlet of the reaction tank and the detection unit.

Images