Urea hydrolysate chloride ion on-line detection device and method

Abstract

The application discloses a urea hydrolysate chloride ion on-line detection device and method, and belongs to the technical field of chloride ion detection. The device comprises a hydrolysate container, a pipeline system connected with the hydrolysate container, a desalted water supply device, a urea hydrolysate supply device, a chloride ion concentration measuring system connected with the hydrolysate container and a regulator supply device. The desalted water supply device sends desalted water into the hydrolysate container through the pipeline system, and cleans the hydrolysate container and the pipeline system by the desalted water. The urea hydrolysate supply device sends urea hydrolysate into the hydrolysate container through the pipeline system, and mixes, dilutes and cools the urea hydrolysate with the desalted water. The chloride ion concentration measuring system mixes the regulator output by the regulator supply device with the urea hydrolysate output by the hydrolysate container to form a mixed solution, and measures the concentration of chloride ions in the mixed solution. The application effectively solves the technical problem of flash evaporation when directly sampling urea hydrolysate for measurement, and the accuracy of the detection result is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chloride ion detection, and more particularly to a urea hydrolysis liquid chloride ion on-line detection device and method. BACKGROUND

[0002] In the urea hydrolysis ammonia production process, the chloride ion concentration of urea solution is extremely low when it is input into the urea hydrolysis reactor, usually less than 1 mg / L, but after continuous enrichment and concentration in the urea hydrolysis reactor during operation, the chloride ion concentration in the urea hydrolysis liquid can reach hundreds or even tens of thousands of milligrams per liter, far exceeding the critical concentration of chloride ion corrosion resistance of 316L and other materials, which can easily lead to corrosion and cracking of the urea hydrolysis reactor cylinder and heat exchanger coil; therefore, during the operation of the urea hydrolysis reactor, the chloride ion concentration in the urea solution and the urea hydrolysis liquid needs to be monitored to adjust the operating conditions, so that the chloride ion concentration in the urea hydrolysis reactor is maintained at a normal level, achieving the purpose of reducing equipment corrosion.

[0003] The current detection methods such as ion chromatography, spectrophotometry, and Mohr method for determining chloride ion concentration are complex in operation and require manual operation and judgment, making it difficult to achieve full-automatic on-line monitoring; on the other hand, since the internal temperature of the urea hydrolysis reactor is maintained at 120-160℃ and the pressure is maintained at about 0.6 MPa during operation, it is difficult to sample the urea solution, and direct sampling of the urea hydrolysis liquid can cause flash evaporation, resulting in a detection result error of more than 10%, which cannot accurately reflect the real chloride ion concentration in the hydrolysis reactor. SUMMARY

[0004] The purpose of the present application is to solve the technical problem that the traditional detection method of directly sampling the urea hydrolysis liquid cannot accurately determine the real chloride ion concentration in the hydrolysis reactor, and a urea hydrolysis liquid chloride ion on-line detection device and method are proposed.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The present application provides a urea hydrolysis liquid chloride ion on-line detection device in the first aspect, which is connected with a desalted water supply device, a urea hydrolysis liquid supply device, and an adjusting agent supply device; the urea hydrolysis liquid chloride ion on-line detection device comprises:

[0007] a hydrolysis liquid container;

[0008] a pipeline system connected with the hydrolysis liquid container; the desalted water supply device delivers desalted water into the hydrolysis liquid container through the pipeline system, and the desalted water is used to clean the hydrolysis liquid container and the pipeline system; the urea hydrolysis liquid supply device delivers urea hydrolysis liquid into the hydrolysis liquid container through the pipeline system to mix and dilute with the desalted water for cooling;

[0009] A chloride ion concentration measuring system is connected to the hydrolysis solution container and the conditioning agent supply device, and is used to mix the conditioning agent output by the conditioning agent supply device with the urea hydrolysis solution output by the hydrolysis solution container to form a mixed solution, and measure the concentration of chloride ions in the mixed solution.

[0010] Further, the chloride ion concentration measuring system comprises:

[0011] A pH value adjusting container is connected to the conditioning agent supply device through a conditioning agent pipeline;

[0012] A conditioning agent pumping device is arranged on the conditioning agent pipeline, and is used to pump the conditioning agent along the conditioning agent pipeline to the pH value adjusting container;

[0013] A measuring device is connected to the pH value adjusting container, and is used to measure the concentration of chloride ions in the mixed solution output by the pH value adjusting container.

[0014] Further, the pipeline system comprises:

[0015] A first desalted water input pipeline is connected to the desalted water supply device at one end, and a first control valve is arranged on the first desalted water input pipeline;

[0016] A general conveying pipeline is connected to the hydrolysis solution container and the first desalted water input pipeline at two ends, and desalted water is input into the hydrolysis solution container through the first desalted water input pipeline and the general conveying pipeline; a third control valve is arranged on the general conveying pipeline;

[0017] A urea hydrolysis solution input pipeline is connected to the urea hydrolysis solution supply device and the general conveying pipeline at two ends, and urea hydrolysis solution is input into the hydrolysis solution container through the urea hydrolysis solution input pipeline and the general conveying pipeline; a second control valve is arranged on the urea hydrolysis solution input pipeline;

[0018] A first waste liquid discharge pipeline is connected to the hydrolysis solution container at one end, and a fourth control valve is arranged on the first waste liquid discharge pipeline;

[0019] A urea hydrolysis solution branch pipeline is connected to the urea hydrolysis solution input pipeline and the first waste liquid discharge pipeline at two ends, and is used to directly discharge the urea hydrolysis solution in the urea hydrolysis solution input pipeline; a fifth control valve is arranged on the urea hydrolysis solution branch pipeline;

[0020] A first mixed solution conveying pipe, two ends of the first mixed solution conveying pipe are communicated with the pH value adjusting container and the hydrolysis solution container respectively, and is used for conveying the diluted and cooled urea hydrolysis solution; the first mixed solution conveying pipe is provided with a sixth control valve;

[0021] A second mixed solution conveying pipe, two ends of the second mixed solution conveying pipe are communicated with the pH value adjusting container and the measuring device respectively, and is used for conveying the mixed solution after the adjustment; the second mixed solution conveying pipe is provided with a seventh control valve;

[0022] A second desalted water input pipe, two ends of the second desalted water input pipe are communicated with the pH value adjusting container and the first desalted water input pipe respectively, and is used for inputting the desalted water into the pH value adjusting container; the second desalted water input pipe is provided with an eighth control valve;

[0023] A second waste liquid discharge pipe, two ends of the second waste liquid discharge pipe are communicated with the pH value adjusting container and the first waste liquid discharge pipe respectively; the second waste liquid discharge pipe is provided with a ninth control valve.

[0024] Further, the measuring device adopts a chloride ion selective electrode or a spectrophotometer.

[0025] The second aspect of the present application provides a chloride ion detection method, which adopts the urea hydrolysis solution chloride ion on-line detection device in the first aspect, and comprises the following steps:

[0026] Washing the hydrolysis solution container and the pH value adjusting container;

[0027] Diluting and cooling the urea hydrolysis solution to obtain the diluted urea hydrolysis solution;

[0028] According to the type of the measuring device, the pH value of the diluted urea hydrolysis solution is adjusted to obtain the mixed solution;

[0029] Measuring the chloride ion concentration of the mixed solution;

[0030] According to the chloride ion concentration value of the mixed solution, the chloride ion concentration value of the urea hydrolysis solution is calculated and obtained.

[0031] Further, the washing of the hydrolysis solution container comprises the following steps:

[0032] Controlling the pipeline system to make the hydrolysis solution container communicated with the desalted water supply device;

[0033] Injecting the desalted water into the hydrolysis solution container to a set liquid level;

[0034] Discharging the desalted water in the hydrolysis solution container;

[0035] The washing pH value adjusting container step includes:

[0036] Controlling the pipeline system to connect the pH value adjusting container with the demineralized water supply device;

[0037] Injecting demineralized water into the pH value adjusting container to a set liquid level;

[0038] Emptying the demineralized water in the pH value adjusting container.

[0039] Further, the diluting and cooling the urea hydrolysate step includes:

[0040] Controlling the pipeline system to connect the hydrolysate container with the demineralized water supply device and injecting V1 volume of demineralized water into the hydrolysate container;

[0041] Removing the residual demineralized water in the pipeline system;

[0042] Controlling the pipeline system to connect the hydrolysate container with the urea hydrolysate supply device and injecting V2 volume of urea hydrolysate into the hydrolysate container.

[0043] Further, the adjusting the pH value of the diluted urea hydrolysate according to the type of measuring device step includes:

[0044] If the measuring device is a chloride ion selective electrode, adjusting the pH value of the diluted urea hydrolysate to below 5.8;

[0045] If the measuring device is a spectrophotometer, adjusting the pH value of the diluted urea hydrolysate to below 4.0 and injecting excess silver nitrate solution.

[0046] Further, the adjusting the pH value of the diluted urea hydrolysate to obtain a mixed solution step includes:

[0047] Controlling the pipeline system to connect the hydrolysate container with the pH value adjusting container and injecting V3 volume of the diluted urea hydrolysate into the pH value adjusting container;

[0048] Injecting V4 volume of the adjusting agent into the pH value adjusting container;

[0049] Controlling the pipeline system to connect the demineralized water supply device with the pH value adjusting container and injecting V5 volume of demineralized water into the pH value adjusting container.

[0050] Further, in the calculating and obtaining the chloride ion concentration value of the urea hydrolysate step, the chloride ion concentration value of the urea hydrolysate is calculated according to the following formula: c0=c*n1*n2.

[0051] In the formula, c0 is the chloride ion concentration value of the urea hydrolysate, c is the chloride ion concentration value of the mixed solution, n1 is the dilution multiple of the urea hydrolysate in the hydrolysate container, and n2 is the dilution multiple of the diluted urea hydrolysate in the pH value adjusting container.

[0052] The urea hydrolysate chloride ion on-line detection device and method provided by the application can effectively solve the technical problem of flash evaporation when directly sampling the urea hydrolysate for measurement, and the accuracy of the detection result is guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 Fig. 1 is a structure schematic diagram of a urea hydrolysate chloride ion on-line detection device provided in an embodiment of the application;

[0054] Figure 2 Fig. 4 is a flow direction schematic diagram of desalted water when cleaning the hydrolysate container in the embodiment of the application;

[0055] Figure 3 Fig. 5 is a flow direction schematic diagram of desalted water when cleaning the pH value adjusting container in the embodiment of the application;

[0056] Figure 4 Fig. 6 is a flow direction schematic diagram of urea hydrolysate when discharging residual desalted water in the pipeline in the embodiment of the application;

[0057] Figure 5 Fig. 7 is a flow direction schematic diagram of urea hydrolysate in the embodiment of the application;

[0058] The marks in the figure are as follows:

[0059] 1, hydrolysate container; 11, liquid level meter; 12, first stirring device;

[0060] 21, first desalted water input pipeline; 211, first control valve; 212, non-return valve; 22, urea hydrolysate input pipeline; 221, second control valve; 222, filter; 23, general conveying pipeline; 231, third control valve; 24, first waste liquid discharge pipeline; 241, fourth control valve; 25, urea hydrolysate branch pipeline; 251, fifth control valve; 26, first mixed solution conveying pipeline; 261, sixth control valve; 27, second mixed solution conveying pipeline; 271, seventh control valve; 28, second desalted water input pipeline; 281, eighth control valve; 29, second waste liquid discharge pipeline; 291, ninth control valve;

[0061] 31, pH adjusting vessel; 311, pH meter; 312, second stirring device; 321, acid regulator delivery pump; 322, silver nitrate solution delivery pump; 33, measuring device. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort fall within the protection scope of the present application.

[0063] It should be noted that all the directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications also change accordingly.

[0064] In the present application, unless otherwise explicitly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium; can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For a person of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0065] In addition, if the present application has descriptions involving "first", "second", etc., the "first", "second", etc. are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features with "first" and "second" can explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes A solution, or B solution, or A and B solutions. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope of the present application.

[0066] Please refer to Figures 1 to 5The embodiment of the application shown provides a urea hydrolysate chloride ion on-line detection device. In actual application, the urea hydrolysate chloride ion on-line detection device is connected with a desalted water supply device, a urea hydrolysate supply device and an adjusting agent supply device, and the desalted water, the adjusting agent and the urea hydrolysate to be detected are mixed in sequence, and then the chloride ion concentration in the urea hydrolysate is measured. It can be understood that the desalted water supply device can adopt any one of a reverse osmosis desalted water device, an EDI electric desalted water treatment device and an electrodialyzer, or other devices capable of supplying desalted water. The urea hydrolysate supply device can adopt a urea hydrolyzer or other devices capable of containing urea hydrolysate.

[0067] The urea hydrolysate chloride ion on-line detection device provided by the application comprises a hydrolysate container 1, a pipeline system and a chloride ion concentration measuring system. The hydrolysate container 1 is a place for dilution and cooling of the urea hydrolysate, and is provided with a liquid level gauge 11 connected thereto for observing the liquid level in the hydrolysate container 1. The pipeline system is connected with the hydrolysate container 1, and a desalted water supply device supplies desalted water into the hydrolysate container 1 through the pipeline system, and a urea hydrolysate supply device supplies urea hydrolysate into the hydrolysate container 1 through the pipeline system.

[0068] More specifically, the pipeline system comprises a first desalted water input pipeline 21, a urea hydrolysate input pipeline 22, a general conveying pipeline 23 and a first waste liquid discharge pipeline 24. One end of the first desalted water input pipeline 21 is connected with the desalted water supply device, and the two ends of the general conveying pipeline 23 are respectively connected with the hydrolysate container 1 and the first desalted water input pipeline 21. The desalted water output by the desalted water supply device flows into the hydrolysate container 1 through the first desalted water input pipeline 21 and the general conveying pipeline 23 in sequence. One end of the urea hydrolysate input pipeline 22 is connected with the urea hydrolysate supply device, and the other end thereof is connected with the general conveying pipeline 23. The urea hydrolysate output by the urea hydrolysate supply device flows into the hydrolysate container 1 through the urea hydrolysate input pipeline 22 and the general conveying pipeline 23 in sequence. One end of the first waste liquid discharge pipeline 24 is connected with the hydrolysate container 1, and the other end thereof can be connected with an external waste water treatment system or a directly connected underground waste water storage tank. The waste liquid generated in the hydrolysate container 1 is discharged from the urea hydrolysate chloride ion on-line detection device through the first waste liquid discharge pipeline 24.

[0069] By using the above technical scheme, the desalted water is injected into the hydrolysate container 1 through the pipeline system, and then the urea hydrolysate is injected into the hydrolysate container 1 to mix with the desalted water. The low-temperature desalted water absorbs the heat in the urea hydrolysate, so that the purpose of cooling and dilution is achieved, and the flash evaporation phenomenon during the subsequent chloride ion concentration measurement can be avoided. On the other hand, the desalted water is used to flush the hydrolysate container 1 and the pipelines of the pipeline system, so that the influence of the residual solution on the detection result is eliminated.

[0070] In the above technical solution, the pipeline system further comprises a urea hydrolysate branch pipeline 25, two ends of the urea hydrolysate branch pipeline 25 being communicated with the urea hydrolysate input pipeline 22 and the first waste liquid discharge pipeline 24 respectively; before the urea hydrolysate is input into the hydrolysate container 1, the urea hydrolysate continuously flushes the urea hydrolysate input pipeline 22 by using the urea hydrolysate output by the urea hydrolysate supply device, and the residual desalted water in the pipeline is discharged; after the flushing is completed, the waste liquid formed is discharged from the urea hydrolysate chlorine ion online detection device along the urea hydrolysate branch pipeline 25 and the first waste liquid discharge pipeline 24.

[0071] In the embodiment, the first desalted water input pipeline 21 is provided with a first control valve 211 and a check valve 212; the first control valve 211 is used for controlling the state of the desalted water supply device for delivering desalted water to the general conveying pipeline 23; and the check valve 212 is used for preventing the backflow of the desalted water and the urea hydrolysate into the desalted water supply device; the urea hydrolysate input pipeline 22 is provided with a second control valve 221 and a filter 222; the second control valve 221 is used for controlling the state of the urea hydrolysate supply device for delivering urea hydrolysate to the general conveying pipeline 23; and the filter 222 is used for filtering the suspended matter in the urea hydrolysate, further reducing the interference factors to the chlorine ion concentration detection result; the general conveying pipeline 23 is provided with a third control valve 231; the third control valve 231 is used as a total valve for controlling the on-off state between the hydrolysate container 1 and the first desalted water input pipeline 21 and the urea hydrolysate input pipeline 22; the first waste liquid discharge pipeline 24 is provided with a fourth control valve 241; the fourth control valve 241 is used for controlling the discharge state of the waste liquid in the hydrolysate container 1; and the urea hydrolysate branch pipeline 25 is provided with a fifth control valve 251; the fifth control valve 251 is used for controlling the flow direction of the urea hydrolysate in the urea hydrolysate input pipeline 22, so as to switch the flow direction of the urea hydrolysate between the two flow directions of being input into the hydrolysate container 1 for cooling, dilution and being input into the urea hydrolysate branch pipeline 25 for flushing the pipeline.

[0072] As a preferred embodiment of the present application, the hydrolysate container 1 is internally provided with a first stirring device 12; the first stirring device 12 is located at the bottom of the hydrolysate container 1, and is used for uniformly mixing the desalted water and the urea hydrolysate in the hydrolysate container 1.

[0073] The urea hydrolysate chlorine ion online detection device provided by the present application effectively solves the technical problem of the flash evaporation phenomenon occurring when the urea hydrolysate is directly sampled for measurement, and the accuracy of the detection result is guaranteed; and the pipeline system is controlled to flush and remove the residual solution, impurities and other interference factors by using the desalted water, further reducing the measurement error.

[0074] The chloride ion concentration measuring system is connected with the hydrolysis liquid container 1 and the regulator supply device; the chloride ion concentration measuring system comprises a pH value adjusting container 31, a regulator pumping device and a measuring device 33; the pH value adjusting container 31 is connected with the regulator supply device through a regulator pipeline, the regulator pumping device is arranged on the regulator pipeline and is used for pumping the regulator into the pH value adjusting container 31 to mix with the urea hydrolysis liquid; the measuring device 33 is connected with the pH value adjusting container 31; the diluted and cooled urea hydrolysis liquid in the hydrolysis liquid container 1 is transported to the pH value adjusting container 31 to adjust the pH value, so as to eliminate the influence of irrelevant ions on the measurement result; after the pH value adjustment is completed, the mixed solution formed is transported to the measuring device 33 to measure the chloride ion concentration; wherein the pH value adjusting container 31 is connected with a pH meter 311, which is used for cooperating with the regulator pumping device to control the pH value of the mixed solution.

[0075] In the above technical scheme, the pipeline system further comprises a first mixed solution transporting pipeline 26, a second mixed solution transporting pipeline 27, a second desalted water input pipeline 28 and a second waste liquid discharging pipeline 29; two ends of the first mixed solution transporting pipeline 26 are respectively connected with the pH value adjusting container 31 and the hydrolysis liquid container 1, and are used for transporting the urea hydrolysis liquid from the hydrolysis liquid container 1 to the pH value adjusting container 31; the first mixed solution transporting pipeline 26 is provided with a sixth control valve 261, which is used for controlling the on-off state of the first mixed solution transporting pipeline 26; two ends of the second mixed solution transporting pipeline 27 are respectively connected with the pH value adjusting container 31 and the measuring device 33, and are used for transporting the mixed solution in the pH value adjusting container 31 to the measuring device 33 to measure the chloride ion concentration; the second mixed solution transporting pipeline 27 is provided with a seventh control valve 271; two ends of the second desalted water input pipeline 28 are respectively connected with the pH value adjusting container 31 and the first desalted water input pipeline 21; the second desalted water input pipeline 28 is provided with an eighth control valve 281; before the urea hydrolysis liquid is input into the pH value adjusting container 31, the eighth control valve 281 is controlled, so that the desalted water enters the pH value adjusting container 31 along the second desalted water input pipeline 28 to flush the pH value adjusting container 31, so as to remove the residual solution in the pH value adjusting container 31; two ends of the second waste liquid discharging pipeline 29 are respectively connected with the pH value adjusting container 31 and the first waste liquid discharging pipeline 24; the second waste liquid discharging pipeline 29 is provided with a ninth control valve 291; the desalted water after flushing the pH value adjusting container 31 and the mixed solution remaining after the measurement are all discharged from the pH value adjusting container 31 through the second waste liquid discharging pipeline 29.

[0076] In the embodiment, the measuring device 33 can adopt a chloride ion selective electrode or a spectrophotometer; further, the regulator supply device can include an acid regulator supply device and a silver nitrate solution supply device; the regulator pumping device includes an acid regulator delivery pump 321 and a silver nitrate solution delivery pump 322; wherein the acid regulator supply device delivers the acid regulator to the pH value adjusting container 31 through the acid regulator delivery pump 321, and the acid regulator can be any one of nitric acid, sulfuric acid, and acetic acid; the silver nitrate solution supply device delivers the silver nitrate solution to the pH value adjusting container 31 through the silver nitrate solution delivery pump 322. The above design makes the urea hydrolysate chloride ion online detection device provided by the application applicable to two ways of measuring the concentration of chloride ions, thereby widening the use range of the detection device; when the measuring device 33 adopts a chloride ion selective electrode, the pH value of the mixed solution is adjusted to below 5.8 by the acid regulator, and the final pH value is preferably 4; when the measuring device 33 adopts a spectrophotometer, the pH value of the mixed solution is adjusted to below 4 by the acid regulator, and the final pH value is preferably 2, and then excess silver nitrate solution is introduced by the silver nitrate solution supply device; the chloride ions and silver ions generate silver chloride which is difficult to dissolve, and the absorbance at the maximum absorption wavelength of 470 nm is measured, compared with the standard curve, and then the chloride ion content in the mixed solution is determined; when the measuring device 33 adopts a spectrophotometer, the urea hydrolysate chloride ion online detection device provided by the application is suitable for the determination of trace chloride ions, and has high accuracy and linear relationship.

[0077] As a preferred embodiment of the application, the second stirring device 312 is arranged in the pH value adjusting container 31, for fully reacting the urea hydrolysate in the pH value adjusting container 31 with the regulator.

[0078] As a preferred embodiment of the application, the urea hydrolysate chloride ion online detection device provided by the application further includes a controller, the first control valve 211, the second control valve 221, the third control valve 231, the fourth control valve 241, the fifth control valve 251, the sixth control valve 261, the seventh control valve 271, the eighth control valve 281, the ninth control valve 291, the acid regulator delivery pump 321, and the silver nitrate solution delivery pump 322 are all in communication connection with the controller; so as to realize remote independent control of the control valves, the acid regulator delivery pump 321, and the silver nitrate solution delivery pump 322.

[0079] The design of the chloride ion concentration measuring system in the technical scheme of the application utilizes the regulator supply device to input the regulator into the urea hydrolysate, converts NH3 into ammonium, and converts carbonate into CO2, so as to eliminate the large amount of free ammonia and carbonate existing in the alkaline urea hydrolysate, thereby avoiding the strong interference of irrelevant ions in the determination of the chloride ion concentration by the spectrophotometry and the ion selective electrode method, and ensuring the accuracy of the final determination result.

[0080] The application also provides a chloride ion detection method in the embodiment, and the detection method adopts the urea hydrolysate chloride ion online detection device in the above embodiment.

[0081] Washing the hydrolysate container 1 and the pH value adjusting container 31;

[0082] The effective capacity of the hydrolysate container 1 is V; in this step, the pipeline system is first controlled to make the hydrolysate container 1 communicate with the desalted water supply device; as an embodiment of the application, please refer to Figure 2 The controller sends instructions to the first control valve 211 and the third control valve 231 to open the first control valve 211 and the third control valve 231, and desalted water is injected into the hydrolysate container 1; the liquid level meter 11 feeds back the liquid level to the controller during the process; after the set liquid level H1 is reached, the controller sends instructions to the first control valve 211 and the third control valve 231 to close the first control valve 211 and the third control valve 231, and the desalted water is used to clean the hydrolysate container 1; the set liquid level H1 can be corresponding to the capacity of the hydrolysate container 1 at most; after the hydrolysate container 1 is fully cleaned, the controller sends instructions to open the fourth control valve 241, and the desalted water in the hydrolysate container 1 is emptied; the liquid level meter 11 feeds back the liquid level signal to the controller during the emptying process, and after the liquid level height in the hydrolysate container 1 is zeroed, the controller sends instructions to close the fourth control valve 241, and thus the cleaning of the hydrolysate container 1 is completed.

[0083] When the pH value adjusting container 31 is cleaned, the pipeline system is first controlled to make the pH value adjusting container 31 communicate with the desalted water supply device; as an embodiment of the application, please refer to Figure 3 The controller sends instructions to open the first control valve 211 and the eighth control valve 281, and after the pH value adjusting container 31 is filled with desalted water, the eighth control valve 281 is closed, and the desalted water is used to clean the pH value adjusting container 31; after the pH value adjusting container 31 is fully cleaned, the controller sends instructions to open the ninth control valve 291, and the desalted water in the pH value adjusting container 31 is emptied, and thus the cleaning of the pH value adjusting container 31 is completed.

[0084] The urea hydrolysate is diluted and cooled to obtain a diluted urea hydrolysate;

[0085] In this step, the pipeline system is first controlled to connect the hydrolysate container 1 with the desalted water supply device; as an embodiment of the present application, the controller sends a command to open the first control valve 211 and the third control valve 231, and injects V1 volume of desalted water into the hydrolysate container 1. When the liquid level meter 11 measures that the desalted water reaches the corresponding liquid level, it feeds back the liquid level signal to the controller. The controller sends a command to close the first control valve 211 and the third control valve 231, and stops injecting desalted water.

[0086] Before injecting the urea hydrolysate into the hydrolysate container 1, the residual desalted water in the pipeline needs to be discharged to avoid mixing of the residual desalted water with the urea hydrolysate in the pipeline and then inputting into the hydrolysate container 1, so as to cause error in the total amount of the urea hydrolysate input into the hydrolysate container 1. Please refer to Figure 4 In this step, the controller sends a command to open the second control valve 221 and the fifth control valve 251. After the urea hydrolysate continuously flushes the pipelines for t1 time, it is discharged through the urea hydrolysate branch pipeline 25 and the first waste liquid discharge pipeline 24, and the second control valve 221 and the fifth control valve 251 are closed.

[0087] After the residual desalted water is discharged, the pipeline system is controlled to connect the hydrolysate container 1 with the urea hydrolysate supply device. Please refer to Figure 5 In this step, the controller sends a command to open the second control valve 221 and the third control valve 231. After the urea hydrolysate is filtered through the filter 222, it is injected into the hydrolysate container 1. The liquid level meter 11 feeds back the liquid level signal to the controller. When the urea hydrolysate injected into the hydrolysate container 1 reaches V2 volume, the controller sends a command to close the second control valve 221 and the third control valve 231, and stops injecting the urea hydrolysate. The first stirring device 12 in the hydrolysate container 1 is started to mix the urea hydrolysate and the desalted water uniformly, and dilute desalted water is obtained. At this time, the dilution multiple n1 of the urea hydrolysate in the hydrolysate container is (V1+V2) / V2.

[0088] According to the type of the measuring device 33, the pH value of the diluted urea hydrolysate is adjusted to obtain a mixed solution.

[0089] The step of adjusting the pH value of the diluted urea hydrolysate includes: controlling the pipeline system to connect the hydrolysate container with the pH value adjusting container 31; as an embodiment of the present application, the controller sends a command to open the sixth control valve 261, so that V3 volume of the diluted urea hydrolysate is injected from the hydrolysate container 1 into the pH value adjusting container 31; then the controller sends a command to start the adjusting agent pumping device to inject V4 volume of the adjusting agent into the pH value adjusting container 31, and synchronously starts the second stirring device 312 to make the adjusting agent fully react with the diluted urea hydrolysate; the pH value of the diluted urea hydrolysate in the pH value adjusting container 31 is detected by the pH meter 311, and a feedback signal is sent to the controller, and the adjusting agent pumping device is closed when the pH value detected by the pH meter 311 reaches the set value; the eighth control valve 281 is opened to connect the desalted water supply device with the pH value adjusting container 31, and V5 volume of the desalted water is injected into the pH value adjusting container 31, and the desalted water is uniformly mixed with the diluted urea hydrolysate and the adjusting agent to form a mixed solution; wherein the volume V3 of the diluted urea hydrolysate, the volume V4 of the adjusting agent and the volume V5 of the desalted water in the pH value adjusting container 31 satisfy: 0

[0090] In the above technical solution, the adjusting agent of the corresponding type should be selected according to the type of the measuring device 33, and the diluted urea hydrolysate should be controlled to be in different pH value ranges; if the measuring device 33 is a chloride ion selective electrode, the acidic adjusting agent pumping device 321 is started to adjust the pH value of the diluted urea hydrolysate to be below 5.8, and the optimal value is 4;

[0091] If the measuring device 33 is a spectrophotometer, the acidic adjusting agent pumping device 321 is first started to adjust the pH value of the diluted urea hydrolysate to be below 4, and the optimal value is 2; then the silver nitrate solution pumping device 322 is started to inject excess silver nitrate solution into the pH value adjusting container 31.

[0092] The chloride ion concentration of the mixed solution is measured; according to the chloride ion concentration value of the mixed solution, the chloride ion concentration value of the urea hydrolysate is calculated and obtained;

[0093] In this step, the seventh control valve 271 is opened to transport the mixed solution in the pH value adjusting container 31 to the measuring device 33 to measure and obtain the chloride ion concentration value c of the mixed solution; after the measurement is completed, the ninth control valve 291 is opened to empty the remaining mixed solution in the pH value adjusting container 31. According to the chloride ion concentration value c of the mixed solution, the chloride ion concentration value c0 of the urea hydrolysate is further obtained as c*n1*n2, and the dilution ratios n1 and n2 are calculated by volume ratio to ensure the linear relationship of the concentration conversion.

[0094] In the formula, c0 is the chloride ion concentration value of the urea hydrolysate; c is the chloride ion concentration value of the mixed solution; n1 is the dilution multiple of the urea hydrolysate in the hydrolysate container; and n2 is the dilution multiple of the diluted urea hydrolysate in the pH value adjusting container.

[0095] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solution and the inventive concept of the present application, can make equivalent replacements or changes within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for detecting chloride ions, using a urea hydrolysate chloride ion on-line detection device connected to a desalted water supply device, a urea hydrolysate supply device, and a conditioning agent supply device, characterized by, The urea hydrolysate chloride ion on-line detection device comprises: a hydrolysate container; a pipeline system connected with the hydrolysate container; a desalted water supply device supplies desalted water into the hydrolysate container through the pipeline system, and the hydrolysate container and the pipeline system are cleaned by the desalted water; a urea hydrolysate supply device supplies urea hydrolysate into the hydrolysate container through the pipeline system to mix, dilute and cool the urea hydrolysate with the desalted water; a chloride ion concentration measuring system connected with the hydrolysate container and an adjusting agent supply device, which is used to mix the adjusting agent output by the adjusting agent supply device with the urea hydrolysate output by the hydrolysate container to form a mixed solution, and measure the chloride ion concentration in the mixed solution; the chloride ion concentration measuring system comprises: a pH value adjusting container connected with the adjusting agent supply device through an adjusting agent pipeline; an adjusting agent pumping device arranged on the adjusting agent pipeline and used to pump the adjusting agent along the adjusting agent pipeline into the pH value adjusting container; a measuring device connected with the pH value adjusting container and used to measure the chloride ion concentration in the mixed solution output by the pH value adjusting container; the urea hydrolysate diluted and cooled in the hydrolysate container is supplied into the pH value adjusting container to adjust the pH value, so as to eliminate the influence of irrelevant ions on the measurement result; after the pH value adjustment is completed, the mixed solution is supplied into the measuring device to measure the chloride ion concentration; wherein the measuring device adopts a chloride ion selective electrode or a spectrophotometer; if the measuring device is a chloride ion selective electrode, the pH value of the diluted urea hydrolysate is adjusted to below 5.8; if the measuring device is a spectrophotometer, the pH value of the diluted urea hydrolysate is adjusted to below 4.0, and excess silver nitrate solution is introduced.

2. The method of claim 1, wherein the method is used to detect chloride ions. the pipeline system comprises: a first desalted water input pipeline, one end of which is connected with a desalted water supply device; a first control valve is arranged on the first desalted water input pipeline; a general conveying pipeline, two ends of which are respectively connected with the hydrolysate container and the first desalted water input pipeline; desalted water is input into the hydrolysate container through the first desalted water input pipeline and the general conveying pipeline; a third control valve is arranged on the general conveying pipeline; a urea hydrolysate input pipeline, two ends of which are respectively connected with a urea hydrolysate supply device and the general conveying pipeline; urea hydrolysate is input into the hydrolysate container through the urea hydrolysate input pipeline and the general conveying pipeline; a second control valve is arranged on the urea hydrolysate input pipeline; a first waste liquid discharge pipeline, one end of which is connected with the hydrolysate container; a fourth control valve is arranged on the first waste liquid discharge pipeline; A urea hydrolysate branch pipeline, two ends of the urea hydrolysate branch pipeline are communicated with the urea hydrolysate input pipeline and the first waste liquid discharge pipeline respectively, and the urea hydrolysate branch pipeline is used for directly discharging the urea hydrolysate in the urea hydrolysate input pipeline; the fifth control valve is arranged on the urea hydrolysate branch pipeline; A first mixed solution conveying pipeline, two ends of the first mixed solution conveying pipeline are communicated with the pH value adjusting container and the hydrolysate container respectively, and the first mixed solution conveying pipeline is used for conveying the diluted and cooled urea hydrolysate; the sixth control valve is arranged on the first mixed solution conveying pipeline; A second mixed solution conveying pipeline, two ends of the second mixed solution conveying pipeline are communicated with the pH value adjusting container and the measuring device respectively, and the second mixed solution conveying pipeline is used for conveying the mixed solution after adjustment; the seventh control valve is arranged on the second mixed solution conveying pipeline; A second desalted water input pipeline, two ends of the second desalted water input pipeline are communicated with the pH value adjusting container and the first desalted water input pipeline respectively, and the second desalted water input pipeline is used for inputting the desalted water into the pH value adjusting container; the eighth control valve is arranged on the second desalted water input pipeline; A second waste liquid discharge pipeline, two ends of the second waste liquid discharge pipeline are communicated with the pH value adjusting container and the first waste liquid discharge pipeline respectively; the ninth control valve is arranged on the second waste liquid discharge pipeline.

3. The method of claim 2, wherein the method is used to detect chloride ions. The chloride ion detection method comprises the following steps: Washing the hydrolysate container and the pH value adjusting container; Diluting and cooling the urea hydrolysate to obtain diluted urea hydrolysate; Adjusting the pH value of the diluted urea hydrolysate according to the type of the measuring device to obtain a mixed solution; Measuring the chloride ion concentration of the mixed solution; According to the chloride ion concentration value of the mixed solution, the chloride ion concentration value of the urea hydrolysate is calculated.

4. The method of claim 3, wherein the chloride ion is detected by a method comprising: The washing step of the hydrolysate container comprises: Controlling the pipeline system to connect the hydrolysate container with the desalted water supply device; Injecting the desalted water into the hydrolysate container to a set liquid level; Emptying the desalted water in the hydrolysate container; The washing step of the pH value adjusting container comprises: Controlling the pipeline system to connect the pH value adjusting container with the desalted water supply device; Injecting the desalted water into the pH value adjusting container to a set liquid level; Emptying the desalted water in the pH value adjusting container.

5. The method of claim 3, wherein the step of detecting the chloride ion is performed by using a chloride ion selective electrode. The diluting and cooling step of the urea hydrolysate comprises: Controlling the pipeline system to connect the hydrolysate container with the desalted water supply device and injecting V1 volume of the desalted water into the hydrolysate container; Removing the residual desalted water in the pipeline system; Controlling the pipeline system to connect the hydrolysate container with the urea hydrolysate supply device and injecting V2 volume of the urea hydrolysate into the hydrolysate container.

6. The method of claim 3, wherein the chloride ion is detected by a method comprising: The adjusting step of the pH value of the diluted urea hydrolysate to obtain a mixed solution comprises: Controlling the pipeline system to connect the hydrolysate container with the pH value adjusting container and injecting V3 volume of the diluted urea hydrolysate into the pH value adjusting container; Injecting V4 volume of the adjusting agent into the pH value adjusting container; Controlling the pipeline system to connect the desalted water supply device with the pH value adjusting container and injecting V5 volume of the desalted water into the pH value adjusting container.

7. The method of claim 3, wherein the method is used for detecting chloride ions. The calculation and acquisition of the urea hydrolysate chloride ion concentration value step, the urea hydrolysate chloride ion concentration value calculation formula is as follows: c0=c*n1*n2; In the formula, c0 is the urea hydrolysate chloride ion concentration value; c is the chloride ion concentration value of the mixed solution; n1 is the dilution multiple of the urea hydrolysate in the hydrolysate container; n2 is the dilution multiple of the diluted urea hydrolysate in the pH value adjusting container.

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