Device and method for measuring chlorine ion content in kettle liquid of urea hydrolyzer

Abstract

The invention discloses a urea hydrolyzer kettle liquid chloride ion content determination device and method, and the device comprises a sampling unit which is used for quantitatively collecting urea hydrolyzer kettle liquid; the ammonia distillation unit is connected with an outlet of the sampling unit and comprises a heating device and a gas release port, and the heating device is used for heating the urea hydrolyzer kettle liquid sample until urea is completely decomposed into NH3 and CO2; the quantifying unit is connected with an outlet of the ammonia distilling unit, the volume of the quantifying unit is the same as that of the sampling unit, and the quantifying unit is provided with a first demineralized water supplementing inlet so as to recover the volume of a kettle liquid sample of the urea hydrolyzer; and the measuring unit is connected with an outlet of the quantifying unit and is used for measuring the concentration of Cl <-> in the kettle liquid sample of the urea hydrolyzer. The invention aims to carry out online monitoring on chloride ions in the kettle liquid of the urea hydrolyzer so as to judge whether sewage needs to be discharged to reduce the concentration of the chloride ions in the kettle liquid and ensure the safe and economical operation of the urea hydrolyzer.

Description

Technical Field

[0001] The present invention relates to the field of online monitoring of thermal power plants, and in particular to a device and method for determining the chloride ion content of kettle liquid in a urea hydrolyzer. Background Art

[0002] Nitrogen oxides (NO x ) is one of the main causes of acid rain, photochemical smog and ozone layer depletion, which is extremely harmful to the atmospheric environment and human health. Environmental protection laws and regulations have strict restrictions on pollutant emissions from power plants. Denitrification is a necessary measure to meet ultra-low emission standards. Mainstream denitrification technologies (such as SCR and SNCR) can convert NO x The denitrification efficiency can reach over 90%. The basic principle of denitrification in coal-fired power plants is as follows: Ammonia is injected into the flue gas at 300-400℃ as a reducing agent under the action of a catalyst (such as V2O5-WO3 / TiO2) to convert NO x Reduced to N2 and H2O.

[0003] 4NO+4NH3+O2→4N2+6H2O

[0004] NO+NO2+2NH3→2N2+3H2O

[0005] Because liquid ammonia is a flammable, explosive, and toxic hazardous chemical, storage exceeding 40 tons poses a significant hazard, posing a significant threat to the safety of residents within the plant and surrounding areas. Urea, on the other hand, is non-toxic and non-flammable, requiring no special safety measures for transportation and storage. Its decomposition products (ammonia and CO2) fully participate in the denitrification reaction, eliminating secondary pollution and completely eliminating the risk of liquid ammonia leaks and explosions. Currently, the mainstream urea-to-ammonia processes used in SCR denitrification systems in coal-fired power plants are urea hydrolysis and urea pyrolysis. Urea hydrolysis involves the reaction of a urea solution with water at 140-160°C and a pressure of 0.4-0.6 MPa to produce ammonia (NH3) and carbon dioxide (CO2). Urea pyrolysis, on the other hand, involves directly heating an atomized urea solution at 600°C and atmospheric pressure to initially produce ammonia and isocyanic acid (HNCO). HNCO further reacts with water to produce NH3 and CO2. Urea hydrolysis offers advantages in energy efficiency, environmental friendliness, and cost-effectiveness, making it the preferred method for new SCR systems. Urea hydrolysis requires high raw material purity. Even if impurity ions in the raw materials are measured to be very low, as the urea solution decomposes during operation, the impurity ions will continue to concentrate within the urea hydrolysis reactor. Therefore, if the raw materials contain chloride ions, their continued concentration during operation will accelerate pitting corrosion of the hydrolysis reactor's stainless steel, shortening the equipment life. Unrestricted wastewater discharge from the urea hydrolysis reactor not only wastes raw materials and heat energy, but also discharges high-ammonia nitrogen wastewater, increasing the burden on power plant wastewater treatment. A device or method capable of online monitoring of impurity ions such as chloride ions in the reactor fluid could effectively address these issues.

[0006] At present, the main methods for determining chloride ions are silver nitrate titration, potentiometric titration, ion chromatography and electrode method. However, the urea hydrolyzer kettle liquid contains a large amount of ammonia and undecomposed urea. + The reaction produces [Ag(NH3)2] + Therefore, the silver nitrate titration method is not suitable for Cl in the urea hydrolysis reactor. - Similarly, potentiometric titration is not applicable; ion chromatography is suitable for the detection of low-concentration ions, but the urea hydrolyzer kettle liquid contains a large amount of ammonia, which will interfere with the determination of Cl - For the determination of impurity ions, if the ammonia content is reduced by dilution, the impurity ions may not even be detected after dilution because the concentration of impurity ions is much lower than the ammonia content; the pH value applicable to the electrode method is usually 2 to 12, but since the urea hydrolyzer kettle liquid contains a large amount of ammonia and is strongly alkaline, the electrode method is not applicable.

[0007] In summary, the existing methods for determining chloride ions are not applicable to urea hydrolyzer kettle liquid. If online determination is required, the difficulty is even higher. Therefore, there is an urgent need for a method to monitor chloride ions in urea hydrolyzer kettle liquid online to determine whether it is necessary to discharge the wastewater to reduce the Cl in the kettle liquid. - concentration to ensure the safe and economical operation of the urea hydrolysis reactor. Summary of the Invention

[0008] In response to the problems existing in the prior art, the present invention provides a device and method for measuring the chloride ion content in the kettle liquid of a urea hydrolyzer. The purpose is to perform online monitoring of the chloride ions in the kettle liquid of a urea hydrolyzer to determine whether sewage discharge is needed to reduce the chloride ion concentration in the kettle liquid, thereby ensuring the safe and economical operation of the urea hydrolysis reactor.

[0009] In order to solve the above technical problems, the present invention is implemented through the following technical solutions:

[0010] According to a first aspect of the present invention, there is provided a device for measuring chloride ion content in a urea hydrolyzer kettle liquid, comprising:

[0011] Sampling unit, used for quantitative collection of urea hydrolyzer kettle liquid;

[0012] an ammonia evaporation unit connected to the outlet of the sampling unit, comprising a heating device and a gas release port, wherein the heating device is used to heat the urea hydrolyzer kettle liquid sample until the urea is completely decomposed into NH3 and CO2;

[0013] a quantitative unit connected to the outlet of the ammonia distillation unit, the volume of the quantitative unit being the same as that of the sampling unit, and provided with a first desalted water replenishment inlet for restoring the volume of the urea hydrolyzer kettle liquid sample;

[0014] The measuring unit is connected to the outlet of the quantitative unit and is used to measure the Cl- concentration in the urea hydrolyzer kettle liquid sample.

[0015] In a possible implementation of the first aspect, the sampling unit adopts a bottom-in and top-out structure, with a sampling inlet for collecting urea hydrolyzer kettle liquid provided at the bottom and an overflow port provided at the top.

[0016] In a possible implementation of the first aspect, the online measurement system further includes:

[0017] The pre-purification unit is used to filter solid impurities in the kettle liquid of the urea hydrolyzer, and the outlet of the pre-purification unit is connected to the sampling inlet of the sampling unit.

[0018] In a possible implementation of the first aspect, a second desalted water supply inlet is further provided on the top of the sampling unit.

[0019] In a possible implementation of the first aspect, the gas release port is provided with a heating device, and the heating device is used to maintain the gas release temperature ≥ 140°C.

[0020] In a possible implementation of the first aspect, a volume of the ammonia evaporation unit is 1.5 to 1.8 times a volume of the sampling unit.

[0021] In a possible implementation of the first aspect, a third desalted water supply inlet is provided on the ammonia distillation unit.

[0022] In a possible implementation of the first aspect, a first cooling jacket is provided outside the sampling unit, and cooling water is passed through the first cooling jacket to cool the urea hydrolyzer kettle liquid sample in the sampling unit to 25±1° C.;

[0023] A second cooling jacket is provided on the outside of the quantitative unit, and cooling water is passed into the second cooling jacket to cool the urea hydrolyzer kettle liquid sample in the quantitative unit to 25±1°C.

[0024] In a possible implementation manner of the first aspect, the measuring unit is a Cl − selective electrode or an online ion chromatograph.

[0025] According to a second aspect of the present invention, a method for online determination of chloride ions in the kettle liquid of a urea hydrolyzer is provided, which uses the above-mentioned device for determining chloride ion content in the kettle liquid of a urea hydrolyzer, comprising the following steps:

[0026] The urea hydrolyzer kettle liquid is passed into the sampling unit, the urea hydrolyzer kettle liquid is quantitatively collected and transported to the ammonia distillation unit;

[0027] In the ammonia distillation unit, a heating device is used to heat the urea hydrolyzer kettle liquid sample until the urea is completely decomposed into NH3 and CO2;

[0028] Open the gas release port and keep the urea hydrolyzer kettle liquid sample boiling until NH3 and CO2 are discharged;

[0029] The treated urea hydrolyzer kettle liquid sample is transported to the quantitative unit, and the deionized water is replenished through the first deionized water replenishing inlet to the initial urea hydrolyzer kettle liquid quantitative collection volume;

[0030] Transported to the measuring unit for online detection of Cl- concentration.

[0031] Compared with the prior art, the present invention has at least the following beneficial effects:

[0032] The present invention provides a device for determining the chloride ion content in the kettle liquid of a urea hydrolyzer, based on the fact that urea can be completely decomposed into NH3 and CO2 at high temperature, and NH3 and CO2 will escape from water in the form of gas at high temperature, while the Cl in the sample - It will still retain the characteristics of being in the liquid phase. First remove the residual urea in the kettle liquid and the NH3 and CO2 produced by decomposition, and then measure the Cl- concentration online, which can effectively prevent Cl- - The risk of causing pitting corrosion of the urea hydrolysis reactor equipment is avoided, and at the same time, the problem of blindly discharging pollutants causing waste of raw materials, heat energy and the generation of a large amount of ammonia nitrogen wastewater is avoided. Since chloride ion concentration will accelerate the pitting corrosion of the stainless steel material of the hydrolysis reactor and shorten the life of the equipment, by accurately measuring the Cl- concentration in the kettle liquid, it can be timely judged whether it is necessary to discharge pollutants to reduce the Cl- concentration, and effectively prevent the risk of Cl-inducing pitting corrosion of the urea hydrolysis reactor equipment. In other words, the present invention can accurately judge the timing of pollutant discharge by measuring the Cl- concentration in the kettle liquid online, avoid the loss of raw materials and heat energy caused by blindly discharging pollutants, and reduce production costs. At the same time, it reduces the high ammonia nitrogen wastewater generated by pollutant discharge, alleviates the burden of wastewater treatment in power plants, saves wastewater treatment costs, and improves the overall economic benefits of power plants.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the specific embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1This is a schematic diagram of a device for measuring chloride ion content in a urea hydrolyzer kettle liquid according to Example 1 of the present invention.

[0036] Figure 2 This is a schematic diagram of a device for measuring chloride ion content in a urea hydrolyzer kettle liquid according to Example 2 of the present invention.

[0037] In the figure: 101-sampling unit; 102-sampling inlet; 103-overflow port; 104-second desalted water supply inlet; 105-first cooling jacket; 201-ammonia evaporation unit; 202-gas release port; 203-heating device; 204-third desalted water supply inlet; 301-quantification unit; 302-first desalted water supply inlet; 303-second cooling jacket; 401-measuring unit; 501-pre-purification unit. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] An embodiment of the present invention provides a device for measuring chloride ion content in the kettle liquid of a urea hydrolyzer. The device primarily comprises a sampling unit 101, an ammonia evaporation unit 201, a quantitative unit 301, a measuring unit 401, connecting pipes, and a corrosion-resistant pump. Each unit is connected by pipes and pumps to enable sequential sample transport and processing. The sample transport pipes, pumps, and containers in direct contact with the sample are all made of 316L stainless steel, ensuring the system's corrosion resistance.

[0040] The sampling unit 101 is a container with a fixed volume and a bottom-in, top-out structure. A sampling inlet 102 is located at the bottom for collecting urea hydrolyzer kettle liquid, and an overflow port 103 and a second desalted water supply inlet 104 are located at the top. A first cooling jacket 105 is installed externally, through which cooling water is passed to cool the sample to 25±1°C. During sampling, urea hydrolysis reactor kettle liquid enters the sampling unit 101 through the lower sampling inlet 102. As the kettle liquid continues to flow in, excess sample is discharged through the overflow port 103 of the sampling unit 101, ensuring that the container is full. During this process, cooling water circulates within the first cooling jacket 105, cooling the sample and stabilizing the sample temperature at 25±1°C. When flushing the pipeline is necessary, desalted water can be introduced into the sampling unit 101 through the second desalted water supply inlet 104. This desalted water is used to flush the pipeline and remove any impurities and residual sample.

[0041] Preferably, a pre-purification unit 501 is installed at the front end of the sampling unit 101. The pre-purification unit 501 can be in the form of a strong magnetic iron removal device, a filtering device, etc. When the kettle liquid of the urea hydrolysis reactor enters the pre-purification unit 501, the strong magnetic iron removal device can absorb ferromagnetic impurities in the kettle liquid, and the filtering device can filter out solid particles, corrosion products and other impurities in the kettle liquid, performing preliminary purification treatment on the kettle liquid to prevent these impurities from entering the subsequent system and extending the service life of the device. The kettle liquid treated by the pre-purification unit 501 is then transported to the sampling unit 101 through a pipeline for sampling.

[0042] The ammonia evaporation unit 201 is a container with a heating function, with a volume 1.5-1.8 times that of the sampling unit 101. It is equipped with a heating device, a gas release port 202, a heat tracer 203, and a third desalted water inlet 204. The heating device heats the sample to a high temperature, completely decomposing the urea into NH3 and CO2. The gas release port 202 is used to discharge the decomposition gas, the heat tracer 203 is used to maintain the gas release temperature at ≥140°C, and the third desalted water inlet 204 is used to replenish water lost during the gas release process. After the sample in the sampling unit 101 is completely transferred to the ammonia evaporation unit 201, all inlet and outlet valves of the ammonia evaporation unit 201 are closed. The heating device is activated to heat the temperature in the ammonia evaporation unit 201 to 175±5°C and maintain it for 40 minutes. Experiments have shown that a 50% urea solution at 175±5°C completely decomposes into NH3 and CO2 within 30 minutes. In this embodiment, the heating time is controlled to 40 minutes to ensure complete urea decomposition. During the heating process, the residual urea in the sample is completely decomposed into NH3 and CO2. The gas release port 202 of the ammonia evaporation unit 201 is then opened, along with the heating device 203 of the gas release pipeline, to prevent NH3 and CO2 from crystallizing in the pipeline due to the drop in temperature. During the gas release process, the heating function of the ammonia evaporation unit 201 is kept on, and deionized water is replenished through the third deionized water replenishment port 204 to prevent complete evaporation of the sample. The sample in the ammonia evaporation unit 201 is kept boiling for 20 minutes to completely release the dissolved NH3 and CO2 in the sample.

[0043] The quantification unit 301 is a container of the same volume as the sampling unit 101. It is equipped with a second cooling jacket 303, which cools the sample to 25±1°C through cooling water. After the sample in the ammonia evaporation unit 201 is completely transferred to the quantification unit 301, deionized water is replenished through the first deionized water replenishment inlet 302 on the quantification unit 301 to restore the sample volume to the sampling volume and prevent the impact of volume changes on the Cl- concentration. During the deionized water replenishment process, cooling water circulates within the second cooling jacket 303, cooling the sample and maintaining a stable temperature of 25±1°C.

[0044] Measurement unit 401 is connected to the outlet of quantification unit 301 and is used to measure the Cl- concentration in the urea hydrolyzer kettle liquid sample. Measurement unit 401 can utilize a Cl-selective electrode or an online ion chromatograph. After the sample is delivered to measurement unit 401, the Cl- concentration in the sample is measured online using the Cl-selective electrode or ion chromatograph. If a Cl-selective electrode is used, it reacts specifically with the Cl- in the sample, generating an electrical signal. The Cl- concentration is determined by measuring the magnitude of the electrical signal. If an online ion chromatograph is used, the Cl- in the sample is separated in a chromatographic column. The peak area or peak height of the Cl- is then detected by a detector, and the Cl- concentration is calculated based on a standard curve.

[0045] When performing online chloride ion measurement using the system for measuring chloride ions in the kettle liquid of a thermal power plant using this embodiment, the urea hydrolysis reactor kettle liquid is passed through the sampling unit 101, using a bottom-in, top-out method, until the kettle liquid fills the sampling unit 101. Excess sample is discharged through the overflow port 103. During this process, the sample is cooled to 25±1°C by cooling water in the first cooling jacket 105. The entire sample in the sampling unit 101 is transferred to the ammonia distillation unit 201, and all inlet and outlet valves of the ammonia distillation unit 201 are closed. The heating device is activated to heat the temperature in the ammonia distillation unit 201 to 175±5°C and maintain this temperature for 40 minutes to completely decompose the urea in the sample into NH3 and CO2. The gas release port 202 and the heating device 203 are then opened, and the sample is kept boiling for 20 minutes to release NH3 and CO2. During the gas release process, the heating function is kept on, and deionized water is replenished through the third deionized water replenishment port 204. The entire sample in the ammonia evaporation unit 201 is transferred to the quantitative unit 301. Deionized water is replenished through the first deionized water replenishment inlet 302 to restore the sample volume to the sampling volume. During this time, the sample is cooled to 25±1°C using cooling water in the second cooling jacket 303. The sample in the quantitative unit 301 is transferred to the measurement unit 401, where the Cl- concentration is measured online using a Cl-selective electrode or an online ion chromatograph.

[0046] Through the above specific implementation methods, the embodiments of the present invention can eliminate the influence of urea, NH3 and CO2 in the kettle liquid of the urea hydrolysis reactor on the Cl- determination, and then perform online measurement of the Cl- concentration, effectively preventing the risk of Cl- inducing pitting corrosion of the urea hydrolysis reactor equipment, and at the same time avoiding the problem of blind discharge of pollutants causing waste of raw materials, heat energy and the generation of a large amount of ammonia nitrogen wastewater.

[0047] Example 1

[0048] like Figure 1 As shown, the on-line chloride ion determination device for the kettle liquid of the urea hydrolyzer of a thermal power plant of this embodiment includes a sampling unit 101 , an ammonia evaporation unit 201 , a quantitative unit 301 and a determination unit 401 .

[0049] The sampling unit 101 features a bottom-in, top-out structure, with a sampling inlet 102 at the bottom connected to the urea hydrolyzer kettle liquid sampling port and an overflow port 103 at the top. A first cooling jacket 105 is installed outside the sampling unit 101, through which cooling water is passed to cool the kettle liquid sample to 25±1°C. A second demineralized water inlet 104 is located at the top of the sampling unit 101 for system flushing.

[0050] The inlet of the ammonia evaporation unit 201 is connected to the outlet of the sampling unit 101, and its volume is 1.5 to 1.8 times that of the sampling unit 101. The ammonia evaporation unit 201 has a built-in heating device that can heat the sample to 175±5°C. A gas release port 202 is located at the top of the ammonia evaporation unit 201, and a heat tracing device 203 is installed to maintain the pipeline temperature at least 140°C to prevent crystallization. A third demineralized water inlet 204 is located on the side wall of the ammonia evaporation unit 201 for replenishing water to prevent evaporation.

[0051] The inlet of quantitative unit 301 is connected to the outlet of ammonia evaporation unit 201, and its volume is the same as that of sampling unit 101. A first demineralized water replenishment inlet 302 is provided in quantitative unit 301 to restore the sample volume. A second cooling jacket 303 is provided outside quantitative unit 301 to pass cooling water to cool the sample to 25±1°C.

[0052] The inlet of the measuring unit 401 is connected to the outlet of the quantitative unit 301, and a Cl-selective electrode or an online ion chromatograph is used.

[0053] The method for online determination of chloride ions in the kettle liquid of a urea hydrolyzer in a thermal power plant of this embodiment is as follows: the kettle liquid enters the sampling unit 101 from the sampling inlet 102, and the overflow port 103 discharges excess sample to ensure full volume; cooling water is passed through the first cooling jacket 105 to keep the sample temperature constant at 25±1°C.

[0054] The sample is pumped into the ammonia evaporation unit 201, all valves are closed, and the sample is heated to 175±5°C and kept warm for 40 minutes (to ensure that the urea is completely decomposed into NH3 and CO2); the gas release port 202 and the heating device 203 are opened, and the gas is discharged in a boiling state for 20 minutes, and water is added through the third desalted water inlet 204 to prevent evaporation.

[0055] The treated sample is pumped into the quantitative unit 301 and replenished with water to the initial sampling volume through the first desalted water replenishment inlet 302; cooling water is passed through the second cooling jacket 303 to cool the sample to 25±1°C.

[0056] The sample enters the measurement unit 401 and the Cl − concentration is detected online by a Cl − selective electrode or an online ion chromatograph.

[0057] In this embodiment, all pipes, pumps and containers in contact with samples are made of 316L stainless steel.

[0058] This embodiment can eliminate the urea and NH3 and CO2 in the urea hydrolysis reactor kettle liquid. - The impact of the determination, and then the Cl - The concentration can be measured online to effectively prevent Cl - It reduces the risk of pitting corrosion in urea hydrolysis reactor equipment and avoids the problem of blind sewage discharge that wastes raw materials, heat energy and produces a large amount of ammonia nitrogen wastewater, with high safety, economic and social environmental benefits.

[0059] Example 2

[0060] like Figure 2 As shown, this embodiment adds a pre-purification unit 501 to the first embodiment. The pre-purification unit 501 is located at the front end of the sampling unit 101, with its inlet connected to the urea hydrolyzer kettle liquid sampling port and its outlet connected to the sampling inlet 102. The pre-purification unit 501 uses a strong magnetic iron removal or filtering device to remove solid impurities (such as corrosion products) in the kettle liquid to prevent them from entering subsequent systems, thereby extending the service life of the device.

[0061] Compared with the first embodiment, this embodiment has the same parts except for the addition of the pre-purification unit 501, so the usage thereof will not be described in detail.

[0062] This embodiment can eliminate the urea and NH3 and CO2 in the urea hydrolysis reactor kettle liquid. - The impact of the determination, and then the Cl - The concentration is measured online, and compared with the first embodiment, the service life of this embodiment is longer.

[0063] In the description of the present invention, it should be understood that the terms "upper", "lower", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0064] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0065] In the present invention, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can mean fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0066] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0067] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0068] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above-mentioned embodiments, ordinary technicians in this field should understand that any technician familiar with this technical field can still modify the technical solutions recorded in the above-mentioned embodiments within the technical scope disclosed by the present invention, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered by the protection scope of the present invention.

Claims

1. A device for measuring chloride ion content in a urea hydrolyzer kettle liquid, characterized in that: include: A sampling unit (101) is used for quantitatively collecting the urea hydrolyzer kettle liquid; an ammonia evaporation unit (201), connected to the outlet of the sampling unit (101), comprising a heating device and a gas release port (202), wherein the heating device is used to heat the urea hydrolyzer kettle liquid sample until the urea is completely decomposed into NH3 and CO2; a quantitative unit (301) connected to the outlet of the ammonia evaporation unit (201), the volume of the quantitative unit (301) being the same as that of the sampling unit (101), and being provided with a first desalted water replenishment inlet (302) for recovering the volume of the urea hydrolyzer kettle liquid sample; The measuring unit (401) is connected to the outlet of the quantitative unit (301) and is used to measure the Cl- concentration in the urea hydrolyzer kettle liquid sample.

2. A urea hydrolyzer kettle liquid chloride ion content measuring device according to claim 1, characterized in that, The sampling unit (101) adopts a bottom-in and top-out structure, with a sampling inlet (102) for collecting urea hydrolyzer kettle liquid provided at the bottom and an overflow port (103) provided at the top.

3. A urea hydrolyzer kettle liquid chloride ion content measuring device according to claim 2, characterized in that, The online measurement system also includes: The pre-purification unit (501) is used to filter solid impurities in the kettle liquid of the urea hydrolyzer, and the outlet of the pre-purification unit (501) is connected to the sampling inlet (102) of the sampling unit (101).

4. The device for measuring chloride ion content in urea hydrolyzer kettle liquid according to claim 1, wherein: A second desalted water replenishment inlet (104) is also provided on the top of the sampling unit (101).

5. A device for measuring chloride ion content in a urea hydrolyzer kettle liquid according to claim 1, characterized in that: The gas release port (202) is provided with a heating device (203), and the heating device (203) is used to maintain the gas release temperature ≥140°C.

6. The device for measuring chloride ion content in urea hydrolyzer kettle liquid according to claim 1, wherein: The volume of the ammonia evaporation unit (201) is 1.5 to 1.8 times the volume of the sampling unit (101).

7. The device for measuring chloride ion content in urea hydrolyzer kettle liquid according to claim 1, characterized in that: The ammonia distillation unit (201) is provided with a third desalted water replenishing inlet (204).

8. The device for measuring chloride ion content in urea hydrolyzer kettle liquid according to claim 1, wherein: The sampling unit (101) is provided with a first cooling jacket (105) on the outside, and the first cooling jacket (105) is used to pass cooling water to cool the urea hydrolyzer kettle liquid sample in the sampling unit (101) to 25±1°C; A second cooling jacket (303) is provided outside the quantitative unit (301), and the second cooling jacket (303) is used to pass cooling water to cool the urea hydrolyzer kettle liquid sample in the quantitative unit (301) to 25±1°C.

9. The device for measuring chloride ion content in urea hydrolyzer kettle liquid according to claim 1, wherein: The measuring unit (401) is a Cl-selective electrode or an online ion chromatograph.

10. A method for determining the chloride ion content in the kettle liquid of a urea hydrolyzer, characterized in that: The device for measuring chloride ion content in the kettle liquid of a urea hydrolyzer according to any one of claims 1 to 9 comprises the following steps: The urea hydrolyzer kettle liquid is passed into the sampling unit (101), the urea hydrolyzer kettle liquid is quantitatively collected and transported to the ammonia distillation unit (201); In an ammonia distillation unit (201), a urea hydrolyzer kettle liquid sample is heated by a heating device until the urea is completely decomposed into NH3 and CO2; Opening the gas release port (202) to keep the urea hydrolyzer kettle liquid sample in a boiling state until NH3 and CO2 are discharged; The treated urea hydrolyzer kettle liquid sample is transported to the quantitative unit (301), and the deionized water is replenished through the first deionized water replenishing inlet (302) to the initial urea hydrolyzer kettle liquid quantitative collection volume; The product is transported to the measuring unit (401) for online detection of Cl- concentration.

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