Urea hydrolysate chloride ion online detection equipment and method

Abstract

The invention discloses a urea hydrolysate chloride ion online detection device and method, and belongs to the technical field of chloride ion detection. The pipeline system is connected with the hydrolysate container; a demineralized water supply device conveys demineralized water into the hydrolysate container through the pipeline system, and the hydrolysate container and the pipeline system are cleaned through the demineralized water; the urea hydrolysate supply equipment conveys urea hydrolysate into the hydrolysate container through the pipeline system, and the urea hydrolysate is mixed with demineralized water to be diluted and cooled; the chloride ion concentration measuring system is connected with the hydrolysate container and the regulator supply equipment and is used for mixing the regulator output by the regulator supply equipment and the urea hydrolysate output by the hydrolysate container to form a mixed solution and measuring the concentration of chloride ions in the mixed solution; according to the invention, the technical problem of flash evaporation during measurement by directly sampling the urea hydrolysate is effectively solved, and the accuracy of the detection result is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of chloride ion detection, and more specifically, to an on-line detection device and method for chloride ions in urea hydrolysis solution. Background Technique

[0002] In the urea hydrolysis to ammonia process, the chloride ion concentration of the urea solution is extremely low when it is input into the urea hydrolyzer, usually less than 1 mg / L. However, after being continuously enriched and concentrated during the operation of the urea hydrolyzer, the chloride ion concentration in the urea hydrolysis solution can reach hundreds or even tens of thousands of milligrams per liter, far exceeding the chloride ion corrosion critical concentration of materials such as 316L, which easily leads to corrosion and cracking of the cylinder body and heat exchanger coil of the urea hydrolyzer. Therefore, during the operation of the urea hydrolyzer, it is necessary to monitor the chloride ion concentration in the urea solution and urea hydrolysis solution to adjust the operating conditions so that the chloride ion concentration in the urea hydrolyzer is maintained at a normal level to achieve the purpose of reducing equipment corrosion.

[0003] At present, the operation of detecting the chloride ion concentration by using detection methods such as ion chromatography, spectrophotometry, and Mohr method is complex, requires manual operation and discrimination, and it is difficult to achieve full-automatic on-line monitoring. On the other hand, since the internal temperature of the urea hydrolyzer is maintained at 120°C - 160°C and the pressure is maintained at about 0.6 MPa during operation, it is difficult to sample the urea solution at this time, and direct sampling of the urea hydrolysis solution will cause flash evaporation, resulting in an error in the detection result reaching more than 10%, and it cannot accurately reflect the true chloride ion concentration in the hydrolyzer. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problem that the traditional detection method of directly sampling the urea hydrolysis solution cannot accurately measure the true chloride ion concentration in the hydrolyzer, and to propose an on-line detection device and method for chloride ions in urea hydrolysis solution.

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

[0006] The first aspect of the present invention provides an on-line detection device for chloride ions in urea hydrolysis solution, which is connected to a demineralized water supply device, a urea hydrolysis solution supply device, and a regulator supply device; the on-line detection device for chloride ions in urea hydrolysis solution includes:

[0007] A hydrolysis solution container;

[0008] A pipeline system, which is connected to the hydrolysis solution container; the demineralized water supply device transports demineralized water to the hydrolysis solution container through the pipeline system and cleans the hydrolysis solution container and the pipeline system with demineralized water; the urea hydrolysis solution supply device transports the urea hydrolysis solution to the hydrolysis solution container through the pipeline system to be mixed, diluted, and cooled with demineralized water;

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

[0010] Furthermore, the chloride ion concentration measuring system includes:

[0011] A pH value adjustment container, which is connected to the regulator supply device through a regulator pipeline;

[0012] A regulator pumping device, which is arranged on the regulator pipeline and is used to pump the regulator along the regulator pipeline into the pH value adjustment container;

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

[0014] Furthermore, the pipeline system includes:

[0015] A first demineralized water input pipeline, one end of which is connected to the demineralized water supply device; a first control valve is provided on the first demineralized water input pipeline;

[0016] A general conveying pipeline, both ends of which are respectively connected to the hydrolysis liquid container and the first demineralized water input pipeline. The demineralized water is input into the hydrolysis liquid container through the first demineralized water input pipeline and the general conveying pipeline; a third control valve is provided on the general conveying pipeline;

[0017] A urea hydrolysis liquid input pipeline, both ends of which are respectively connected to the urea hydrolysis liquid supply device and the general conveying pipeline. The urea hydrolysis liquid is input into the hydrolysis liquid container through the urea hydrolysis liquid input pipeline and the general conveying pipeline; a second control valve is provided on the urea hydrolysis liquid input pipeline;

[0018] A first waste liquid discharge pipeline, one end of which is connected to the hydrolysis liquid container; a fourth control valve is provided on the first waste liquid discharge pipeline;

[0019] A urea hydrolysis liquid branch pipeline, both ends of which are respectively connected to the urea hydrolysis liquid input pipeline and the first waste liquid discharge pipeline, and is used to directly discharge the urea hydrolysis liquid in the urea hydrolysis liquid input pipeline; a fifth control valve is provided on the urea hydrolysis liquid branch pipeline;

[0020] The first mixed solution delivery pipeline, with both ends of the first mixed solution delivery pipeline being respectively connected to the pH value adjustment container and the hydrolysis solution container, is used for delivering the diluted and cooled urea hydrolysis solution; a sixth control valve is provided on the first mixed solution delivery pipeline;

[0021] The second mixed solution delivery pipeline, with both ends of the second mixed solution delivery pipeline being respectively connected to the pH value adjustment container and the measuring device, is used for delivering the modulated mixed solution; a seventh control valve is provided on the second mixed solution delivery pipeline;

[0022] The second demineralized water input pipeline, with both ends of the second demineralized water input pipeline being respectively connected to the pH value adjustment container and the first demineralized water input pipeline, is used for enabling demineralized water to enter the pH value adjustment container; an eighth control valve is provided on the second demineralized water input pipeline;

[0023] The second waste liquid discharge pipeline, with both ends of the second waste liquid discharge pipeline being respectively connected to the pH value adjustment container and the first waste liquid discharge pipeline; a ninth control valve is provided on the second waste liquid discharge pipeline.

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

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

[0026] Wash the hydrolysis solution container and the pH value adjustment container;

[0027] Dilute and cool the urea hydrolysis solution to obtain a diluted urea hydrolysis solution;

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

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

[0030] According to the chloride ion concentration value of the mixed solution, calculate and obtain the chloride ion concentration value of the urea hydrolysis solution.

[0031] Further, for the step of washing the hydrolysis solution container, the steps include:

[0032] Control the pipeline system to connect the hydrolysis solution container to the demineralized water supply device;

[0033] Inject demineralized water into the hydrolysis solution container to the set liquid level;

[0034] Empty the demineralized water in the hydrolysis solution container;

[0035] The steps of adjusting the pH value of the washing container include:

[0036] Control the pipeline system to connect the pH value adjustment container with the demineralized water supply equipment;

[0037] Inject demineralized water into the pH value adjustment container to the set liquid level;

[0038] Empty the demineralized water in the pH value adjustment container.

[0039] Furthermore, the steps of diluting and cooling the urea hydrolysis solution include:

[0040] Control the pipeline system to connect the hydrolysis solution container with the demineralized water supply equipment, and inject V1 volume of demineralized water into the hydrolysis solution container;

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

[0042] Control the pipeline system to connect the hydrolysis solution container with the urea hydrolysis solution supply equipment, and inject V2 volume of urea hydrolysis solution into the hydrolysis solution container.

[0043] Furthermore, the steps of adjusting the pH value of the diluted urea hydrolysis solution according to the type of measuring device include:

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

[0045] If the measuring device is a spectrophotometer, adjust the pH value of the diluted urea hydrolysis solution to below 4.0, and introduce an excessive amount of silver nitrate solution.

[0046] Furthermore, the steps of adjusting the pH value of the diluted urea hydrolysis solution to obtain a mixed solution include:

[0047] Control the pipeline system to connect the hydrolysis solution container with the pH value adjustment container, and inject V3 volume of diluted urea hydrolysis solution into the pH value adjustment container;

[0048] Inject V4 volume of the regulator into the pH value adjustment container;

[0049] Control the pipeline system to connect the demineralized water supply equipment with the pH value adjustment container, and inject V5 volume of demineralized water into the pH value adjustment container.

[0050] Furthermore, in the step of calculating and obtaining the chloride ion concentration value of the urea hydrolysis solution, the calculation formula for the chloride ion concentration value of the urea hydrolysis solution is as follows: c0 = c * n1 * n2;

[0051] Wherein, c0 is the chloride ion concentration value of the urea hydrolysis solution; c is the chloride ion concentration value of the mixed solution; n1 is the dilution multiple of the urea hydrolysis solution in the hydrolysis solution container; n2 is the dilution multiple of the diluted urea hydrolysis solution in the pH value adjustment container.

[0052] The beneficial effects of the present invention are as follows: An on-line chloride ion detection device and method for urea hydrolysis solution provided by this application, through the design of the hydrolysis solution container and the pipeline system, the urea hydrolysis solution first enters the hydrolysis solution container, is mixed, diluted and cooled with demineralized water, and then goes to the subsequent chloride ion concentration measurement system to measure the chloride ion concentration, effectively solving the technical problem of flash evaporation during direct sampling of urea hydrolysis solution for measurement, and ensuring the accuracy of the detection results; and eliminating the strong interference caused by free ammonia and carbonate ions during the determination of chloride ion concentration by spectrophotometry and ion selective electrode method. Brief Description of the Drawings

[0053] Figure 1 It is a schematic structural diagram of an on-line chloride ion detection device for urea hydrolysis solution provided in an embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of the flow direction of demineralized water when cleaning the hydrolysis solution container in an embodiment of the present invention;

[0055] Figure 3 It is a schematic diagram of the flow direction of demineralized water when cleaning the pH value adjustment container in an embodiment of the present invention;

[0056] Figure 4 It is a schematic diagram of the flow direction of urea hydrolysis solution when discharging the residual demineralized water in the pipeline in an embodiment of the present invention;

[0057] Figure 5 It is a schematic diagram of the flow direction of urea hydrolysis solution in an embodiment of the present invention;

[0058] The markings in the figure are shown as follows:

[0059] 1. Hydrolysis solution container; 11. Liquid level gauge; 12. First stirring device;

[0060] 21. First demineralized water input pipeline; 211. First control valve; 212. Check valve; 22. Urea hydrolysis solution input pipeline; 221. Second control valve; 222. Filter; 23. General transfer pipeline; 231. Third control valve; 24. First waste liquid discharge pipeline; 241. Fourth control valve; 25. Urea hydrolysis solution branch pipeline; 251. Fifth control valve; 26. First mixed solution transfer pipeline; 261. Sixth control valve; 27. Second mixed solution transfer pipeline; 271. Seventh control valve; 28. Second demineralized water input pipeline; 281. Eighth control valve; 29. Second waste liquid discharge pipeline; 291. Ninth control valve;

[0061] 31. pH value adjustment container; 311. pH meter; 312. Second stirring device; 321. Acid regulator delivery pump; 322. Silver nitrate solution delivery pump; 33. Measuring device. Detailed implementation manners

[0062] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

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

[0064] In the present invention, unless otherwise clearly defined and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0065] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. 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 solution A, solution B, or a solution that satisfies both A and B at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0066] Please refer to Figures 1 to 5The embodiment of the present application shown provides an on-line chloride ion detection device for urea hydrolysis solution. In actual application, the on-line chloride ion detection device for urea hydrolysis solution is connected to the demineralized water supply device, the urea hydrolysis solution supply device, and the regulator supply device. First, demineralized water and a regulator are used to mix with the urea hydrolysis solution to be measured, and then the chloride ion concentration in the urea hydrolysis solution is further measured. It can be understood that the demineralized water supply device can be any one of a reverse osmosis demineralized water device, an EDI electro-deionized water treatment device, and an electrodialyzer, or other devices capable of supplying demineralized water. The urea hydrolysis solution supply device can be a urea hydrolyzer or other devices capable of containing urea hydrolysis solution.

[0067] The on-line chloride ion detection device for urea hydrolysis solution provided by the present application includes: a hydrolysis solution container 1, a pipeline system, and a chloride ion concentration measurement system. The hydrolysis solution container 1 is a place for diluting and cooling the urea hydrolysis solution. A liquid level gauge 11 is connected to the hydrolysis solution container 1 for observing the liquid level height in the hydrolysis solution container 1. The pipeline system is connected to the hydrolysis solution container 1. The demineralized water supply device transports demineralized water into the hydrolysis solution container 1 through the pipeline system, and the urea hydrolysis solution supply device transports the urea hydrolysis solution into the hydrolysis solution container 1 through the pipeline system.

[0068] More specifically, the pipeline system includes: a first demineralized water input pipeline 21, a urea hydrolysis solution input pipeline 22, a general transportation pipeline 23, and a first waste liquid discharge pipeline 24. One end of the first demineralized water input pipeline 21 is connected to the demineralized water supply device, and both ends of the general transportation pipeline 23 are respectively connected to the hydrolysis solution container 1 and the first demineralized water input pipeline 21. The demineralized water output by the demineralized water supply device flows through the first demineralized water input pipeline 21 and the general transportation pipeline 23 in sequence and enters the hydrolysis solution container 1. One end of the urea hydrolysis solution input pipeline 22 is connected to the urea hydrolysis solution supply device, and the other end is connected to the general transportation pipeline 23. The urea hydrolysis solution output by the urea hydrolysis solution supply device flows through the urea hydrolysis solution input pipeline 22 and the general transportation pipeline 23 in sequence and enters the hydrolysis solution container 1. One end of the first waste liquid discharge pipeline 24 is connected to the hydrolysis solution container 1, and the other end can be connected to an external wastewater treatment system or directly connected to a sump wastewater storage tank. The waste liquid generated in the hydrolysis solution container 1 is discharged from the on-line chloride ion detection device for urea hydrolysis solution through the first waste liquid discharge pipeline 24.

[0069] With the above technical solution, after injecting demineralized water into the hydrolysis solution container 1 through the pipeline system, the urea hydrolysis solution is then injected into the hydrolysis solution container 1 to mix with the demineralized water. The low-temperature demineralized water absorbs the heat in the urea hydrolysis solution to achieve the purpose of cooling and dilution, and can avoid the flash evaporation phenomenon during the subsequent chloride ion concentration measurement. On the other hand, the demineralized water is used to flush the hydrolysis solution container 1 and each pipeline of the pipeline system, eliminating the influence of the residual solution on the detection result.

[0070] In the above technical solution, the pipeline system further includes a urea hydrolysis solution branch pipeline 25. Both ends of the urea hydrolysis solution branch pipeline 25 are respectively communicated with a urea hydrolysis solution input pipeline 22 and a first waste liquid discharge pipeline 24. Before the urea hydrolysis solution is input into the hydrolysis solution container 1, the urea hydrolysis solution output by the urea hydrolysis solution supply device is used to continuously flush the urea hydrolysis solution input pipeline 22 to discharge the residual demineralized water in the pipeline. After the flushing is completed, the waste liquid formed is discharged from the urea hydrolysis solution chloride ion on-line detection device along the urea hydrolysis solution branch pipeline 25 and the first waste liquid discharge pipeline 24.

[0071] In this embodiment, a first control valve 211 and a check valve 212 are provided on the first demineralized water input pipeline 21. The first control valve 211 is used to control the state of the demineralized water supply device for supplying demineralized water to the general conveying pipeline 23, and the check valve 212 is used to prevent the demineralized water and urea hydrolysis solution from flowing back into the demineralized water supply device; a second control valve 221 and a filter 222 are provided on the urea hydrolysis solution input pipeline 22. The second control valve 221 is used to control the state of the urea hydrolysis solution supply device for supplying urea hydrolysis solution to the general conveying pipeline 23, and the filter 222 is used to filter out the suspended substances in the urea hydrolysis solution to further reduce the factors interfering with the chloride ion concentration detection result; a third control valve 231 is provided on the general conveying pipeline 23. The third control valve 231 is used as a main valve to control the on-off state between the hydrolysis solution container 1 and the first demineralized water input pipeline 21 and the urea hydrolysis solution input pipeline 22; a fourth control valve 241 is provided on the first waste liquid discharge pipeline 24. The fourth control valve 241 is used to control the discharge state of the waste liquid in the hydrolysis solution container 1; a fifth control valve 251 is provided on the urea hydrolysis solution branch pipeline 25. The fifth control valve 251 is used to control and change the flow direction of the urea hydrolysis solution in the urea hydrolysis solution input pipeline 22, so that the urea hydrolysis solution can be switched between two flow directions: cooling and diluting in the input hydrolysis solution container 1 and flushing the pipeline in the input urea hydrolysis solution branch pipeline 25.

[0072] As a preferred embodiment of the present application, a first stirring device 12 is provided inside the hydrolysis solution container 1. The first stirring device 12 is located at the bottom of the hydrolysis solution container 1 and is used to mix the demineralized water and urea hydrolysis solution in the hydrolysis solution container 1 evenly.

[0073] A urea hydrolysis solution chloride ion on-line detection device provided by the present application, through the design of the hydrolysis solution container 1 and the pipeline system, the urea hydrolysis solution first enters the hydrolysis solution container 1 to be mixed, diluted and cooled with the demineralized water, and then goes to the subsequent chloride ion concentration measurement system to measure the chloride ion concentration, effectively solving the technical problem of flash evaporation during direct sampling of urea hydrolysis solution for measurement, and ensuring the accuracy of the detection result; and the pipeline system is controlled to use demineralized water to flush and remove influencing factors such as residual solution and impurities, further reducing the measurement error.

[0074] The chloride ion concentration measurement system is connected to the hydrolysis solution container 1 and the regulator supply device; the chloride ion concentration measurement system includes: a pH adjustment container 31, a regulator pumping device, and a measurement device 33; the pH adjustment container 31 is connected to the regulator supply device through a regulator pipeline, and the regulator pumping device is arranged on the regulator pipeline for pumping the regulator into the pH adjustment container 31 to be mixed with the urea hydrolysis solution; the measurement device 33 is connected to the pH adjustment container 31; the urea hydrolysis solution after dilution and cooling in the hydrolysis solution container 1 is transported to the pH adjustment container 31 to adjust the pH value to eliminate the influence of irrelevant ions on the measurement result, and the mixed solution formed after the pH value adjustment is then transported to the measurement device 33 to measure the chloride ion concentration; wherein, a pH meter 311 is connected to the pH adjustment container 31 for cooperating with the regulator pumping device to control the pH value of the mixed solution.

[0075] In the above technical solution, the pipeline system further includes: a first mixed solution delivery pipeline 26, a second mixed solution delivery pipeline 27, a second demineralized water input pipeline 28, and a second waste liquid discharge pipeline 29; both ends of the first mixed solution delivery pipeline 26 are respectively communicated with the pH adjustment container 31 and the hydrolysis solution container 1 for transporting the urea hydrolysis solution from the hydrolysis solution container 1 to the pH adjustment container 31; a sixth control valve 261 is arranged on the first mixed solution delivery pipeline 26 for controlling the on-off state of the first mixed solution delivery pipeline 26; both ends of the second mixed solution delivery pipeline 27 are respectively communicated with the pH adjustment container 31 and the measurement device 33 for transporting the mixed solution in the pH adjustment container 31 to the measurement device 33 to measure the chloride ion concentration; a seventh control valve 271 is arranged on the second mixed solution delivery pipeline 27; both ends of the second demineralized water input pipeline 28 are respectively communicated with the pH adjustment container 31 and the first demineralized water input pipeline 21; an eighth control valve 281 is arranged on the second demineralized water input pipeline 28; before the urea hydrolysis solution enters the pH adjustment container 31, the eighth control valve 281 is controlled to enable the demineralized water to enter the pH adjustment container 31 along the second demineralized water input pipeline 28 to wash the pH adjustment container 31 to remove the residual solution in the pH adjustment container 31; both ends of the second waste liquid discharge pipeline 29 are respectively communicated with the pH adjustment container 31 and the first waste liquid discharge pipeline 24; a ninth control valve 291 is arranged on the second waste liquid discharge pipeline 29; the demineralized water after washing the pH adjustment container 31 and the remaining mixed solution after measurement are both discharged from the pH adjustment container 31 through the second waste liquid discharge pipeline 29.

[0076] In this embodiment, the measuring device 33 can adopt a chloride ion selective electrode or a spectrophotometer; further, the regulator supply device can include: an acidic regulator supply device and a silver nitrate solution supply device; the regulator pumping device includes: an acidic regulator transfer pump 321 and a silver nitrate solution transfer pump 322; wherein, the acidic regulator supply device transports the acidic regulator to the pH adjustment container 31 through the acidic regulator transfer pump 321, and the acidic regulator can be any one of nitric acid, sulfuric acid, and acetic acid; the silver nitrate solution supply device transports the silver nitrate solution to the pH adjustment container 31 through the silver nitrate solution transfer pump 322. The above design enables the on-line chloride ion detection device for urea hydrolysis solution provided by this application to be applicable to two chloride ion concentration measurement methods, broadening the scope of use 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 through the acidic regulator, and the final pH value is preferably 4 at this time; when the measuring device 33 adopts a spectrophotometer, the acidic regulator is introduced to adjust the pH value of the mixed solution to below 4, and the final pH value is preferably 2 at this time, and then an excessive amount of silver nitrate solution is introduced through the silver nitrate solution supply device; chloride ions react with silver ions to form insoluble silver chloride, and by measuring its absorbance at the maximum absorption wavelength of 470 nm and comparing it with the standard curve, the chloride ion content in the mixed solution is determined; when the measuring device 33 adopts a spectrophotometer, the on-line chloride ion detection device for urea hydrolysis solution provided by this application is applicable to the determination of trace chloride ions and has high accuracy and linear relationship.

[0077] As a preferred embodiment of this application, a second stirring device 312 is arranged inside the pH adjustment container 31 to enable the urea hydrolysis solution and the regulator in the pH adjustment container 31 to react fully.

[0078] As a preferred embodiment of this application, an on-line chloride ion detection device for urea hydrolysis solution provided by this application further includes a controller, and 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 acidic regulator transfer pump 321, and the silver nitrate solution transfer pump 322 are all communicatively connected to the controller; thereby realizing remote independent control of each control valve, the acidic regulator transfer pump 321, and the silver nitrate solution transfer pump 322.

[0079] In the design of the chloride ion concentration measurement system of the technical solution of this application, a regulator supply device is used to input a regulator into the urea hydrolysis solution, convert NH3 into ammonium ions, and convert carbonate ions into CO2, eliminating a large amount of free ammonia and carbonate ions existing in the alkaline urea hydrolysis solution, thereby avoiding strong interference caused by irrelevant ions when measuring the chloride ion concentration by spectrophotometry or ion selective electrode method, and ensuring the accuracy of the final measurement result.

[0080] The present invention also provides a chloride ion detection method in this embodiment. The detection method uses the on-line chloride ion detection device for urea hydrolysis solution in the above embodiment. Specifically, the steps of the control method include:

[0081] Wash the hydrolysis solution container 1 and the pH value adjustment container 31;

[0082] The effective capacity of the hydrolysis solution container 1 is V; in this step, first control the pipeline system to connect the hydrolysis solution container 1 with the demineralized water supply device; as an implementation manner of this application, please refer to Figure 2 , send instructions to the first control valve 211 and the third control valve 231 through the controller, open the first control valve 211 and the third control valve 231, and inject demineralized water into the hydrolysis solution container 1; during the process, the liquid level is fed back to the controller through the liquid level gauge 11; after reaching the set liquid level H1, send instructions to the first control valve 211 and the third control valve 231 through the controller again to close the first control valve 211 and the third control valve 231, and use demineralized water to wash the hydrolysis solution container 1; the set liquid level H1 can correspond to the maximum capacity of the hydrolysis solution container 1 at most; after the hydrolysis solution container 1 is fully washed, the controller sends instructions to the fourth control valve 241 to open the fourth control valve 241 to drain the demineralized water in the hydrolysis solution container 1; during the draining process, the liquid level gauge 11 feeds back the liquid level signal to the controller, and after the liquid level height in the hydrolysis solution container 1 returns to zero, the controller sends instructions to close the fourth control valve 241, thus completing the cleaning of the hydrolysis solution container 1.

[0083] When cleaning the pH value adjustment container 31, first control the pipeline system to connect the pH value adjustment container 31 with the demineralized water supply device; as an implementation manner of this application, please refer to Figure 3 , send instructions to open the first control valve 211 and the eighth control valve 281 through the controller. After the pH value adjustment container 31 is filled with demineralized water, close the eighth control valve 281, and use demineralized water to wash the pH value adjustment container 31. After the pH value adjustment container 31 is fully washed, the controller sends instructions to open the ninth control valve 291 to drain the demineralized water in the pH value adjustment container 31, thus completing the cleaning of the pH value adjustment container 31.

[0084] Dilute and cool the urea hydrolysis solution to obtain a diluted urea hydrolysis solution;

[0085] In this step, first, the pipeline system is controlled to connect the hydrolysis liquid container 1 with the demineralized water supply device. As an implementation manner of the present application, the controller sends an instruction to open the first control valve 211 and the third control valve 231, inject demineralized water with a volume of V1 into the hydrolysis liquid container 1. After the liquid level gauge 11 measures that the demineralized water reaches the corresponding liquid level, it feeds back a liquid level signal to the controller. The controller sends an instruction to close the first control valve 211 and the third control valve 231 to stop injecting demineralized water.

[0086] Before injecting the urea hydrolysis liquid into the hydrolysis liquid container 1, it is necessary to drain the residual demineralized water in the pipeline to avoid the residual demineralized water mixing with the urea hydrolysis liquid in the pipeline and then being input into the hydrolysis liquid container 1, which may cause an error in the total amount of the urea hydrolysis liquid input into the hydrolysis liquid container 1. Please refer to Figure 4 , in this step, the controller sends an instruction to open the second control valve 221 and the fifth control valve 251. After the urea hydrolysis liquid continuously flushes each pipeline for a time t1, it is discharged through the urea hydrolysis liquid branch pipeline 25 and the first waste liquid discharge pipeline 24, and then the second control valve 221 and the fifth control valve 251 are closed.

[0087] After draining the residual demineralized water, the pipeline system is controlled to connect the hydrolysis liquid container 1 with the urea hydrolysis liquid supply device. Please refer to Figure 5 , in this step, the controller sends an instruction to open the second control valve 221 and the third control valve 231. The urea hydrolysis liquid is filtered by the filter 222 and then injected into the hydrolysis liquid container 1. The liquid level gauge 11 feeds back a liquid level signal to the controller. When the volume of the urea hydrolysis liquid injected into the hydrolysis liquid container 1 reaches V2, the controller sends an instruction to close the second control valve 221 and the third control valve 231 to stop injecting the urea hydrolysis liquid; start the first stirring device 12 in the hydrolysis liquid container 1 to mix the urea hydrolysis liquid and the demineralized water evenly to obtain diluted demineralized water; at this time, the dilution multiple n1 of the urea hydrolysis liquid in the hydrolysis liquid container is n1=(V1 + V2) / V2.

[0088] According to the type of the measuring device 33, adjust the pH value of the diluted urea hydrolysis liquid to obtain a mixed solution;

[0089] The steps for adjusting the pH value of the diluted urea hydrolysis solution include: controlling the pipeline system to connect the hydrolysis solution container with the pH value adjustment container 31; as an implementation manner of the present application, sending an instruction through the controller to open the sixth control valve 261, so that a volume V3 of the diluted urea hydrolysis solution is injected from the hydrolysis solution container 1 into the pH value adjustment container 31; then the controller sends an instruction to start the regulator pumping device, inject a volume V4 of the regulator into the pH value adjustment container 31, and simultaneously start the second stirring device 312 to make the regulator fully react with the diluted urea hydrolysis solution; using the pH meter 311 to detect the pH value of the diluted urea hydrolysis solution in the pH value adjustment container 31 and simultaneously feedback a signal to the controller, and closing the regulator pumping device after the pH value measured by the pH meter 311 reaches the set value; opening the eighth control valve 281 to connect the demineralized water supply device with the pH value adjustment container 31, injecting a volume V5 of demineralized water into the pH value adjustment container 31, and the demineralized water, the diluted urea hydrolysis solution, and the regulator are mixed evenly to form a mixed solution; wherein, the volume V3 of the diluted urea hydrolysis solution, the volume V4 of the regulator, and the volume V5 of the demineralized water in the pH value adjustment container 31 respectively satisfy: 0 < V3 < V, 0 < V4 < V, 0 < V5 < V, and V3 + V4 + V5 = V; at this time, the dilution multiple n2 of the diluted urea hydrolysis solution in the pH value adjustment container 31 = (V3 + V4 + V5) / V3.

[0090] In the above technical solution, corresponding types of regulators must be selected according to the type of the measuring device 33 and the diluted urea hydrolysis solution is controlled to be in different pH value ranges; if the measuring device 33 is a chloride ion selective electrode, start the acidic regulator delivery pump 321 to adjust the pH value of the diluted urea hydrolysis solution to below 5.8, and the optimal value is 4;

[0091] If the measuring device 33 is a spectrophotometer, first start the acidic regulator delivery pump 321 to adjust the pH value of the diluted urea hydrolysis solution to below 4, and the optimal value is 2; then start the silver nitrate solution delivery pump 322 to inject an excessive amount of silver nitrate solution into the pH value adjustment container 31.

[0092] Measure the chloride ion concentration of the mixed solution; calculate and obtain the chloride ion concentration value of the urea hydrolysis solution according to the chloride ion concentration value of the mixed solution;

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

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

[0095] As mentioned above, it is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. An on-line chloride ion detection device for urea hydrolysis solution, the on-line chloride ion detection device for urea hydrolysis solution is connected to a demineralized water supply device, a urea hydrolysis solution supply device and a regulator supply device; characterized in that, The on-line chlorine ion detection device for urea hydrolysis solution includes: A hydrolysis solution container; A pipeline system, which is connected to the hydrolysis solution container; the demineralized water supply device transports demineralized water into the hydrolysis solution container through the pipeline system, and cleans the hydrolysis solution container and the pipeline system with demineralized water; the urea hydrolysis solution supply device transports the urea hydrolysis solution into the hydrolysis solution container through the pipeline system to be mixed, diluted and cooled with demineralized water; A chlorine ion concentration measurement system, which is connected to the hydrolysis solution container and the regulator supply device. The chlorine ion concentration measurement system is used to mix the regulator output by the regulator supply device with the urea hydrolysis solution output by the hydrolysis solution container to form a mixed solution, and measure the chlorine ion concentration in the mixed solution.

2. The on-line chloride ion detection device for urea hydrolysis solution according to claim 1, characterized in that, The chlorine ion concentration measurement system includes: A pH value adjustment container, which is connected to the regulator supply device through a regulator pipeline; A regulator pumping device, which is arranged on the regulator pipeline and is used to pump the regulator along the regulator pipeline into the pH value adjustment container; A measurement device, which is connected to the pH value adjustment container and is used to measure the chlorine ion concentration in the mixed solution output by the pH value adjustment container.

3. The on-line chloride ion detection device for urea hydrolysis solution according to claim 2, characterized in that, The pipeline system includes: A first demineralized water input pipeline, one end of which is connected to the demineralized water supply device; a first control valve is arranged on the first demineralized water input pipeline; A general-purpose transport pipeline, both ends of which are respectively connected to the hydrolysis solution container and the first demineralized water input pipeline. Demineralized water is input into the hydrolysis solution container through the first demineralized water input pipeline and the general-purpose transport pipeline; a third control valve is arranged on the general-purpose transport pipeline; A urea hydrolysis solution input pipeline, both ends of which are respectively connected to the urea hydrolysis solution supply device and the general-purpose transport pipeline. The urea hydrolysis solution is input into the hydrolysis solution container through the urea hydrolysis solution input pipeline and the general-purpose transport pipeline; a second control valve is arranged on the urea hydrolysis solution input pipeline; A first waste liquid discharge pipeline, one end of which is connected to the hydrolysis solution container; a fourth control valve is arranged on the first waste liquid discharge pipeline; A urea hydrolysis solution branch pipeline, both ends of which are respectively connected to the urea hydrolysis solution input pipeline and the first waste liquid discharge pipeline, 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; A first mixed solution transport pipeline, both ends of which are respectively connected to the pH value adjustment container and the hydrolysis solution container, and is used to transport the diluted and cooled urea hydrolysis solution; a sixth control valve is arranged on the first mixed solution transport pipeline; The second mixed solution delivery pipeline, with both ends of the second mixed solution delivery pipeline connected to the pH value adjustment container and the measuring device respectively, is used to deliver the modulated mixed solution; a seventh control valve is provided on the second mixed solution delivery pipeline; The second demineralized water input pipeline, with both ends of the second demineralized water input pipeline connected to the pH value adjustment container and the first demineralized water input pipeline respectively, is used to input demineralized water into the pH value adjustment container; an eighth control valve is provided on the second demineralized water input pipeline; The second waste liquid discharge pipeline, with both ends of the second waste liquid discharge pipeline connected to the pH value adjustment container and the first waste liquid discharge pipeline respectively; a ninth control valve is provided on the second waste liquid discharge pipeline.

4. The on-line chloride ion detection device for urea hydrolysis solution according to claim 3, characterized in that, The measuring device uses a chloride ion selective electrode or a spectrophotometer.

5. A method for detecting chloride ions, characterized in that, Using the on-line chloride ion detection equipment for urea hydrolysis solution described in claim 4, includes the following steps: Wash the hydrolysis solution container and the pH value adjustment container; Dilute and cool the urea hydrolysis solution to obtain a diluted urea hydrolysis solution; Adjust the pH value of the diluted urea hydrolysis solution according to the type of measuring device to obtain a mixed solution; Measure the chloride ion concentration of the mixed solution; Calculate and obtain the chloride ion concentration value of the urea hydrolysis solution according to the chloride ion concentration value of the mixed solution.

6. The chloride ion detection method according to claim 5, characterized in that, For the step of washing the hydrolysis solution container, the steps include: Control the pipeline system to connect the hydrolysis solution container with the demineralized water supply equipment; Inject demineralized water into the hydrolysis solution container to the set liquid level; Empty the demineralized water in the hydrolysis solution container; The steps for washing the pH value adjustment container include: Control the pipeline system to connect the pH value adjustment container with the demineralized water supply equipment; Inject demineralized water into the pH value adjustment container to the set liquid level; Empty the demineralized water in the pH value adjustment container.

7. A chloride ion detection method according to claim 5, characterized in that, For the step of diluting and cooling the urea hydrolysis solution, the steps include: Control the pipeline system to connect the hydrolysis solution container with the demineralized water supply equipment and inject V1 volume of demineralized water into the hydrolysis solution container; Remove the residual demineralized water in the pipeline system; Control the pipeline system to connect the hydrolysis solution container with the urea hydrolysis solution supply equipment and inject V2 volume of urea hydrolysis solution into the hydrolysis solution container.

8. A chloride ion detection method according to claim 7, characterized in that, For the step of adjusting the pH value of the diluted urea hydrolysis solution according to the type of measuring device, the steps include: If the measuring device is a chloride ion selective electrode, adjust the pH value of the diluted urea hydrolysis solution to below 5.8; If the measuring device is a spectrophotometer, adjust the pH value of the diluted urea hydrolysis solution to below 4.0 and introduce an excessive amount of silver nitrate solution.

9. The chloride ion detection method according to claim 8, characterized in that For the step of adjusting the pH value of the diluted urea hydrolysis solution to obtain a mixed solution, the steps include: Control the pipeline system to connect the hydrolysis solution container with the pH value adjustment container and inject V3 volume of diluted urea hydrolysis solution into the pH value adjustment container; Inject V4 volume of the regulator into the pH value adjustment container; Control the pipeline system to connect the demineralized water supply equipment with the pH value adjustment container and inject V5 volume of demineralized water into the pH value adjustment container.

10. A chloride ion detection method according to claim 5, characterized in that, In the step of calculating and obtaining the chloride ion concentration value of the urea hydrolysis solution, the calculation formula for the chloride ion concentration value of the urea hydrolysis solution is as follows: c0 = c * n1 * n2; Wherein, c0 is the chloride ion concentration value of the urea hydrolysis solution; c is the chloride ion concentration value of the mixed solution; n1 is the dilution multiple of the urea hydrolysis solution in the hydrolysis solution container; n2 is the dilution multiple of the diluted urea hydrolysis solution in the pH value adjustment container.

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