Online monitoring system and method for sulfite content in desulfurization slurry of power plant

Abstract

The invention discloses a power plant desulfurization slurry sulfite content on-line monitoring system and method, a sample input pipeline is communicated with an inlet of a sample sampling cup, an outlet of the sample sampling cup is communicated with an inlet of a reaction cup, the side surface of the top of the sample sampling cup is provided with an overflow port, a stirrer is arranged in the reaction cup, and the overflow port is communicated with the reaction cup. An outlet of the starch indicator box, an outlet of the Na2S2O3 solution box, an outlet of the hydrochloric acid solution box, an outlet of the iodine standard solution box and an outlet of the high-purity water box are communicated with an inlet of the reaction cup, and the reaction cup is of a transparent structure. According to the system and the method, the content of sulfite in the desulfurization slurry can be accurately measured, and manual operation is not needed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of power generation technology sample detection, and relates to a power plant desulfurization slurry sulfite content online monitoring system and method. BACKGROUND

[0002] Sulfite (such as calcium sulfite, bisulfite, etc.) in the desulfurization slurry is a key intermediate product in the wet desulfurization process (such as the limestone-gypsum method), and its content directly affects the desulfurization efficiency, system stability and by-product quality. Online monitoring of sulfite content has important industrial significance. Sulfite is an intermediate product after SO2 absorption, and its oxidation rate determines the overall efficiency of the desulfurization reaction. Online monitoring can provide real-time feedback on oxidation effects and avoid a decrease in desulfurization efficiency (such as SO2 escape) due to insufficient oxidation. Incomplete oxidation of sulfite in the slurry can easily form soft scale, blocking the spray layer or pipeline. Online monitoring can guide the adjustment of oxidation air volume and reduce the risk of scale formation. Residual sulfite can cause a decrease in gypsum purity, affecting commercial value. Real-time monitoring can ensure complete oxidation and guarantee gypsum quality. Therefore, online monitoring of the sulfite content in the desulfurization slurry is crucial.

[0003] Currently, the sulfite content in the desulfurization slurry of a power plant mainly relies on manual sampling for testing, which is cumbersome and has low measurement accuracy. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provides a power plant desulfurization slurry sulfite content online monitoring system and method, which can accurately measure the sulfite content in the desulfurization slurry without manual operation.

[0005] To achieve the above-mentioned purpose, the present application discloses a power plant desulfurization slurry sulfite content online monitoring system, comprising a sample input pipeline, a sample sampling cup, a reaction cup, a starch indicator tank, a Na2S2O3 solution tank, a hydrochloric acid solution tank, an iodine standard solution tank and a high-purity water tank.

[0006] The sample input pipeline is connected to the inlet of the sample sampling cup, the outlet of the sample sampling cup is connected to the inlet of the reaction cup, an overflow port is formed on the side of the top of the sample sampling cup, a stirrer is arranged in the reaction cup, the outlet of the starch indicator tank is connected to the inlet of the reaction cup, the outlet of the Na2S2O3 solution tank is connected to the inlet of the reaction cup, the outlet of the hydrochloric acid solution tank is connected to the inlet of the reaction cup, the outlet of the iodine standard solution tank is connected to the inlet of the reaction cup, the outlet of the high-purity water tank is connected to the inlet of the reaction cup, the reaction cup is of a transparent structure, and a color sensor is arranged on the outer wall of the reaction cup.

[0007] The further improvement of the power plant desulfurization slurry sulfite content online monitoring system according to the present application is that:

[0008] Further, the sample input pipeline is provided with a desulfurization slurry inlet valve.

[0009] Further, the starch indicator tank is connected with the inlet of the reaction cup through a starch indicator pump.

[0010] Further, the Na2S2O3 solution tank is connected with the inlet of the reaction cup through a Na2S2O3 solution pump.

[0011] Further, the hydrochloric acid solution tank is connected with the inlet of the reaction cup through a hydrochloric acid solution pump.

[0012] Further, the iodine standard solution tank is connected with the inlet of the reaction cup through an iodine standard solution pump.

[0013] Further, the high-purity water tank is connected with the inlet of the reaction cup through a high-purity water pump.

[0014] Further, the reaction cup is provided with a reaction cup blowdown valve at the blowdown port at the bottom of the reaction cup.

[0015] Further, the control and display device is connected with the desulfurization slurry inlet valve, the sample input pump, the reaction cup blowdown valve, the stirrer, the color sensor, the high-purity water pump, the iodine standard solution pump, the hydrochloric acid solution pump, the Na2S2O3 solution pump and the starch indicator pump.

[0016] The application discloses a kind of power plant desulfurization slurry sulfite content online monitoring method, comprising the following steps:

[0017] Control the desulfurization slurry inlet valve to open, and the desulfurization slurry enters sample sampling cup, is discharged through overflow port on sample sampling cup, is then pumped by sample input pump and is sent into reaction cup, is added to reaction cup by iodine standard solution pump, is added to reaction cup by high-purity water pump, is added to reaction cup by hydrochloric acid solution pump, starts stirrer and stirs, then is placed, is started again, Na2S2O3 solution pump is started and Na2S2O3 solution is added to reaction cup for titration, when color sensor detects that the color of liquid in reaction cup becomes light yellow, then stop Na2S2O3 solution pump;Starch indicator pump is started, and starch indicator is added to reaction cup, Na2S2O3 solution pump is started, and is titrated by Na2S2O3 solution, when color sensor detects that the color of water sample in reaction cup changes from blue to colorless, then it indicates that it reaches titration end point, stop Na2S2O3 solution pump, at this moment, the Na2S2O3 solution volume VmL consumed by Na2S2O3 solution pump is recorded.

[0018] According to the consumed Na2S2O3 solution volume VmL, the sulfite content in the sample expressed by sulfur dioxide is calculated.

[0019] The present application has the following beneficial effects:

[0020] The power plant desulfurization slurry sulfite content online monitoring system and method has the advantages that automatic sampling is adopted, automatic detection is performed through a color sensor, the volume VmL of the Na2S2O3 solution consumed is measured through automatic titration, and the sulfite content in the sample is calculated in terms of sulfur dioxide, so that the sulfite content in the desulfurization slurry is accurately measured without manual operation, and the practicability is extremely high. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The embodiments of the application, and their

[0022] Figure 1 is a structural diagram of the present application.

[0023] In the figure, 1 is a desulfurization slurry inlet valve, 2 is a sample sampling cup, 3 is a sample sampling pump, 4 is a reaction cup, 5 is a reaction cup blowdown valve, 6 is a stirrer, 7 is a color sensor, 8 is a high-purity water tank, 9 is a high-purity water pump, 10 is an iodine standard solution tank, 11 is an iodine standard solution pump, 12 is a hydrochloric acid solution tank, 13 is a hydrochloric acid solution pump, 14 is a Na2S2O3 solution tank, 15 is a Na2S2O3 solution pump, 16 is a starch indicator tank, 17 is a starch indicator pump, and 18 is a control and display. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0025] In the description of the present application, it should be understood that the terms "comprise" and "include" indicate the presence of described features, whole, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0026] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should be further understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items, and that the term "and / or" as used herein allows for the inclusion of only a single item, or the inclusion of any and all combinations of one or more items. In addition, the character " / " in the present application generally represents an "or" relationship between the objects before and after it.

[0028] It should be understood that, even though the terms first, second, third, etc. can be used herein to describe various ranges or elements, these ranges or elements should not be limited by these terms. These terms are only used to distinguish one range or element from another. For example, a first range could be termed a second range without departing from the scope of the example embodiments. Similarly, it will be understood that, unless otherwise specified, "a" or "an" can mean one or more than one.

[0029] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "upon determining" or "in response to determining" or "upon detecting [the stated condition or event]" or "in response to detecting [the stated condition or event]."

[0030] In order to make the purposes, technical solutions, and advantages of the example embodiments of the present application clearer, the technical solutions in the example embodiments of the present application will be described clearly and completely below with reference to the drawings in the example embodiments of the present application. Obviously, the described example embodiments are some but not all of the example embodiments of the present application. The components of the example embodiments of the present application described and shown in the accompanying drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the example embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected example embodiments of the present application. Based upon the example embodiments in the present application, all other example embodiments obtained by a person of ordinary skill in the art without creative work should be within the scope of the present application.

[0031] Various structural schematic diagrams according to the disclosed example embodiments of the present application are shown in the accompanying drawings. These diagrams are not drawn to scale, in which some details are exaggerated for the purpose of clarity, and some details can be omitted. The shapes of various regions, layers, and the relative size and position relationship between them shown in the diagrams are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and a person of ordinary skill in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0032] Embodiment one

[0033] Reference Figure 1 The power plant desulfurization slurry sulfite content online monitoring system comprises a sample input pipeline, a desulfurization slurry inlet valve 1, a sample sampling cup 2, a sample injection pump 3, a reaction cup 4, a reaction cup blowdown valve 5, a stirrer 6, a color sensor 7, a high-purity water tank 8, a high-purity water pump 9, an iodine standard solution tank 10, an iodine standard solution pump 11, a hydrochloric acid solution tank 12, a hydrochloric acid solution pump 13, a Na2S2O3 solution tank 14, a Na2S2O3 solution pump 15, a starch indicator tank 16, a starch indicator pump 17 and a control and display 18.

[0034] The sample input pipeline is connected with the inlet of the sample sampling cup 2, the sample input pipeline is provided with the desulfurization slurry inlet valve 1, the outlet of the sample sampling cup 2 is connected with the inlet of the reaction cup 4, the side of the top of the sample sampling cup 2 is provided with an overflow port, the reaction cup 4 is provided with the stirrer 6, and the reaction cup blowdown valve 5 is arranged at the blowdown port of the bottom of the reaction cup 4.

[0035] The starch indicator tank 16 is connected with the inlet of the reaction cup 4 through the starch indicator pump 17.

[0036] The Na2S2O3 solution tank 14 is connected with the inlet of the reaction cup 4 through the Na2S2O3 solution pump 15.

[0037] The hydrochloric acid solution tank 12 is connected with the inlet of the reaction cup 4 through the hydrochloric acid solution pump 13.

[0038] The iodine standard solution tank 10 is connected with the inlet of the reaction cup 4 through the iodine standard solution pump 11.

[0039] The high-purity water tank 8 is connected with the inlet of the reaction cup 4 through the high-purity water pump 9.

[0040] The reaction cup 4 is of a transparent structure, and the color sensor 7 is arranged on the outer wall of the reaction cup 4.

[0041] The control and display 18 is connected with the desulfurization slurry inlet valve 1, the sample injection pump 3, the reaction cup blowdown valve 5, the stirrer 6, the color sensor 7, the high-purity water pump 9, the iodine standard solution pump 11, the hydrochloric acid solution pump 13, the Na2S2O3 solution pump 15 and the starch indicator pump 17.

[0042] Embodiment two

[0043] The power plant desulfurization slurry sulfite content online monitoring method comprises the following steps:

[0044] The control desulfurization slurry inlet valve 1 is opened, the desulfurization slurry enters the sample sampling cup 2, is discharged through the overflow port on the sample sampling cup 2, 10 mL of the sample to be measured is sucked by the sample feeding pump 3 and is sent into the reaction cup 4, 5 mL of the iodine standard solution is added into the reaction cup 4 by the iodine standard solution pump 11, 100 mL of water is added into the reaction cup 4 by the high-purity water pump 9, 5 mL of the hydrochloric acid solution is added into the reaction cup 4 by the hydrochloric acid solution pump 13, the stirrer 6 is started to stir for 2 min, then is placed for 5 min, the stirrer 6 is started again, the Na2S2O3 solution pump 15 is started to add the Na2S2O3 solution into the reaction cup 4 for titration, when the color sensor 7 detects that the color of the liquid in the reaction cup 4 becomes light yellow, the Na2S2O3 solution pump 15 is stopped; the starch indicator pump 17 is started, 1 mL of the starch indicator is added into the reaction cup 4, the Na2S2O3 solution pump 15 is started to carry out titration, when the color sensor 7 detects that the color of the water sample in the reaction cup 4 changes from blue to colorless, it is indicated that the titration end point is reached, the Na2S2O3 solution pump 15 is stopped, at this time, the volume of the Na2S2O3 solution consumed by the Na2S2O3 solution pump is recorded as V mL, after the measurement is completed, the reaction cup drain valve 5 and the high-purity water pump 9 are opened to clean the measurement reaction cup 4.

[0045] The content of the sulfite substance expressed as sulfur dioxide in the sample is SO2%:

[0046] SO2%=(5-V)×0.05×64×100

[0047] It should be noted that each valve is an electric valve, the control ends of each valve are connected with the control and display device 18, the opening and closing of each valve is controlled by the built-in program of the control and display device 18, the operation and cleaning of the system are controlled by the built-in program after being set by the control and display device 18, and manual operation is not needed.

[0048] The control ends of each pump are connected with the control and display device 18, the opening and closing of each pump is controlled by the built-in program of the control and display device 18, wherein the high-purity water pump 9, the iodine standard solution pump 11, the hydrochloric acid solution pump 13 and the starch indicator pump 17 are metering pumps, the solution can be added quantitatively according to the set volume, the Na2S2O3 solution pump 15 can be a plunger pump or a metering pump and the like high-precision pump, and the volume can be accurately controlled and displayed.

[0049] Example three

[0050] The computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the power plant desulfurization slurry sulfite content online monitoring method when executing the computer program, for example, comprising: controlling the desulfurization slurry inlet valve 1 to open, the desulfurization slurry entering the sample sampling cup 2, being discharged through the overflow port on the sample sampling cup 2, then 10 mL of the sample to be measured is sucked by the sample feeding pump 3 and sent into the reaction cup 4, 5 mL of the iodine standard solution is added into the reaction cup 4 by the iodine standard solution pump 11, 100 mL of water is added into the reaction cup 4 by the high-purity water pump 9, 5 mL of the hydrochloric acid solution is added into the reaction cup 4 by the hydrochloric acid solution pump 13, the stirrer 6 is started to stir for 2 min, then is placed for 5 min, the stirrer 6 is started again, the Na2S2O3 solution pump 15 is started to add the Na2S2O3 solution into the reaction cup 4 for titration, when the color sensor 7 detects that the color of the liquid in the reaction cup 4 becomes light yellow, the Na2S2O3 solution pump 15 is stopped; the starch indicator pump 17 is started to add 1 mL of the starch indicator into the reaction cup 4, the Na2S2O3 solution pump 15 is started to titrate by the Na2S2O3 solution, when the color sensor 7 detects that the color of the water sample in the reaction cup 4 changes from blue to colorless, it is indicated that the titration end point is reached, the Na2S2O3 solution pump 15 is stopped, at this time, the volume of the Na2S2O3 solution consumed by the Na2S2O3 solution pump is recorded as V mL, and the content of the sulfite matter represented by sulfur dioxide in the sample is calculated. The memory can comprise a memory, for example, a high-speed random memory, and can also comprise a non-volatile memory, for example, at least one disk memory; the processor, the network interface and the memory are connected to each other through an internal bus, which can be an industry standard architecture bus, a peripheral component interconnect standard bus, an extended industry standard structure bus, etc., and the bus can be divided into an address bus, a data bus, a control bus, etc. The memory is used to store programs, specifically, the programs can comprise program codes, and the program codes comprise computer operation instructions. The memory can comprise a memory and a non-volatile memory, and provides instructions and data to the processor.

[0051] Embodiment four

[0052] A computer readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for on-line monitoring of the content of sulfite in desulfurization slurry of a power plant, for example, including: controlling the desulfurization slurry inlet valve 1 to open, the desulfurization slurry entering the sample sampling cup 2, being discharged through the overflow port on the sample sampling cup 2, then 10 mL of the sample to be measured is sucked by the sample feeding pump 3 and sent into the reaction cup 4, 5 mL of the iodine standard solution is added to the reaction cup 4 by the iodine standard solution pump 11, 100 mL of water is added to the reaction cup 4 by the high-purity water pump 9, 5 mL of the hydrochloric acid solution is added to the reaction cup 4 by the hydrochloric acid solution pump 13, the stirrer 6 is started to stir for 2 min, then stands for 5 min, the stirrer 6 is started again, the Na2S2O3 solution pump 15 is started to add the Na2S2O3 solution to the reaction cup 4 for titration, when the color sensor 7 detects that the color of the liquid in the reaction cup 4 becomes light yellow, the Na2S2O3 solution pump 15 is stopped; the starch indicator pump 17 is started to add 1 mL of the starch indicator to the reaction cup 4, the Na2S2O3 solution pump 15 is started to titrate by the Na2S2O3 solution, when the color sensor 7 detects that the color of the water sample in the reaction cup 4 changes from blue to colorless, it indicates that the titration end point is reached, the Na2S2O3 solution pump 15 is stopped, at this time, the volume of the Na2S2O3 solution consumed by the Na2S2O3 solution pump is recorded as V mL, and the content of the sulfite substance expressed by sulfur dioxide in the sample is calculated. Specifically, the computer readable storage medium includes but is not limited to, for example, volatile memory and / or non-volatile memory. The volatile memory can include random access memory (RAM) and / or cache memory, etc. The non-volatile memory can include read-only memory (ROM), hard disk, flash memory, optical disc, magnetic disc, etc.

[0053] Those skilled in the art will appreciate that embodiments of the application can be supplied as methods, systems, or computer program products. Accordingly, the application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage media, etc.) having computer usable program code embodied in the medium.

[0054] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0055] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0056] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0057] Those skilled in the art will readily identify other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0058] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0059] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. An online monitoring system for sulfite content in desulfurization slurry of a power plant, characterized in that: It comprises a sample input pipe, a sample sampling cup (2), a reaction cup (4), a starch indicator box (16), a Na2S2O3 solution box (14), a hydrochloric acid solution box (12), an iodine standard solution box (10) and a high-purity water tank (8); The sample input pipe is connected to the inlet of the sample sampling cup (2), the outlet of the sample sampling cup (2) is connected to the inlet of the reaction cup (4), an overflow port is provided on the side of the top of the sample sampling cup (2), a stirrer (6) is provided in the reaction cup (4), the outlet of the starch indicator box (16) is connected to the inlet of the reaction cup (4), the outlet of the Na2S2O3 solution box (14) is connected to the inlet of the reaction cup (4), the outlet of the hydrochloric acid solution box (12) is connected to the inlet of the reaction cup (4), the outlet of the iodine standard solution box (10) is connected to the inlet of the reaction cup (4), and the outlet of the high-purity water tank (8) is connected to the inlet of the reaction cup (4). The reaction cup (4) is a transparent structure, and a color sensor (7) is provided on the outer wall of the reaction cup (4).

2. The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 1 is characterized in that: A desulfurization slurry inlet valve (1) is provided on the sample input pipeline.

3. The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 2 is characterized in that: The starch indicator box (16) is connected to the inlet of the reaction cup (4) via the starch indicator pump (17).

4. The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 3 is characterized in that: The Na2S2O3 solution tank (14) is connected to the inlet of the reaction cup (4) via the Na2S2O3 solution pump (15).

5. The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 4 is characterized in that: The hydrochloric acid solution tank (12) is connected to the inlet of the reaction cup (4) via the hydrochloric acid solution pump (13).

6. The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 5, characterized in that: The iodine standard solution box (10) is connected to the inlet of the reaction cup (4) via the iodine standard solution pump (11).

7. The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 6, characterized in that: The high-purity water tank (8) is connected to the inlet of the reaction cup (4) via the high-purity water pump (9).

8. The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 7, characterized in that: A reaction cup drain valve (5) is provided at the drain outlet at the bottom of the reaction cup (4).

9. The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 8, characterized in that: The invention also includes a control and display device (18), which is connected to the desulfurization slurry inlet valve (1), the sample injection pump (3), the reaction cup sewage valve (5), the stirrer (6), the color sensor (7), the high-purity water pump (9), the iodine standard solution pump (11), the hydrochloric acid solution pump (13), the Na2S2O3 solution pump (15) and the starch indicator pump (17).

10. A method for online monitoring of sulfite content in desulfurization slurry of a power plant, characterized in that: The online monitoring system for sulfite content in desulfurization slurry of a power plant according to claim 8 comprises the following steps: The desulfurization slurry inlet valve (1) is controlled to be opened, and the desulfurization slurry enters the sample sampling cup (2), is discharged through the overflow port on the sample sampling cup (2), and then the sample to be tested is sucked by the sample injection pump (3) and sent to the reaction cup (4). The iodine standard solution is added to the reaction cup (4) through the iodine standard solution pump (11), water is added to the reaction cup (4) through the high-purity water pump (9), and hydrochloric acid solution is added to the reaction cup (4) through the hydrochloric acid solution pump (13). The stirrer (6) is started to stir, and then the mixture is allowed to stand. The stirrer (6) is started again, and the Na2S2O3 solution pump (15) is started to add Na2S2O3 to the reaction cup (4). The solution is titrated. When the color sensor (7) detects that the color of the liquid in the reaction cup (4) changes to light yellow, the Na2S2O3 solution pump (15) is stopped. The starch indicator pump (17) is started to add starch indicator to the reaction cup (4). The Na2S2O3 solution pump (15) is started to titrate with the Na2S2O3 solution. When the color sensor (7) detects that the color of the water sample in the reaction cup (4) changes from blue to colorless, it indicates that the titration end point has been reached. The Na2S2O3 solution pump (15) is stopped. At this time, the volume of the Na2S2O3 solution consumed by the Na2S2O3 solution pump is recorded as VmL. The sulfite content in the sample expressed as sulfur dioxide is calculated based on the volume VmL of the consumed Na2S2O3 solution.

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