High-efficiency purification system for high-purity ammonia water

Abstract

The invention relates to the technical field of ammonia water purification, in particular to a high-efficiency purification system for high-purity ammonia water, comprising: a purification module comprising an ion exchange unit, a rectification unit, a vacuum degassing unit, a membrane filtration unit and a chelation adsorption unit to obtain high-purity ammonia water; comprising a first acquisition unit, a second acquisition unit, a third acquisition unit and a fourth acquisition unit; the control module is used for judging whether purification of the refined ammonia water meets a preset standard or not according to the conductivity characterization value of the refined ammonia water and judging whether purification of the finished ammonia water meets the preset standard or not according to the particulate matter concentration of the finished ammonia water; the path selection module is used for determining a purification path under the condition that the purification of the refined ammonia water does not meet the preset standard; and the adjusting module is used for increasing the operating pressure of the membrane filtration unit. The ammonia water purification efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of ammonia purification technology, and in particular to a high-efficiency purification system for high-purity ammonia. Background Technology

[0002] High-purity ammonia water is mainly used in industries such as cleaning and etching of solar photovoltaic cells, printed circuit boards, integrated circuits and ultra-large-scale integrated circuit chips, and is a key chemical raw material in the industrial chain.

[0003] However, traditional purification technologies have significant limitations. Metal ion removal relies on ion exchange resins, but the short regeneration cycle and insufficient selectivity lead to concentration fluctuations. Low-boiling-point impurities are easily left behind by distillation due to issues with tray efficiency or reflux ratio. Dissolved gas removal is energy-intensive and inefficient. Membrane filtration lacks dynamic pressure regulation, resulting in insufficient particulate matter retention accuracy. The lack of multi-parameter collaborative control means that when conductivity, sodium ion concentration, and other parameters are abnormal, the optimal purification path cannot be intelligently selected, and the energy consumption of multi-stage units in series is superimposed.

[0004] Chinese Patent Application Publication No. CN103466656A discloses a method for preparing ultrapure ammonia water by membrane absorption, characterized by the following specific steps: (1) vaporizing liquid ammonia into gaseous ammonia; (2) removing oil from the gaseous ammonia in step (1); specifically, removing high-carbon oil from the gaseous ammonia by membrane method, removing low-carbon oil from the gaseous ammonia by chemical method, and removing water-soluble oil from the gaseous ammonia by resin method; (3) filtering the gaseous ammonia after oil removal in step (2) through membrane filtration to remove impurities; and (4) absorbing the filtered gaseous ammonia in step (3) through membrane absorption to prepare high-purity ammonia water.

[0005] It can be seen that the above technical solution does not take into account the dynamic changes of impurities such as metal ions and dissolved gases during the purification process. Instead, it uses a fixed process to process all materials, which forces high-purity raw materials to undergo redundant purification steps, while low-purity raw materials cannot receive targeted enhanced treatment, resulting in poor ammonia purification efficiency. Summary of the Invention

[0006] Therefore, the present invention provides a high-efficiency purification system for high-purity ammonia water, which overcomes the problem that the existing technology does not consider the dynamic changes of impurities such as metal ions and dissolved gases during the purification process, but instead uses a fixed process to process all materials. This results in high-purity raw materials being forced to undergo redundant purification steps, while low-purity raw materials cannot receive targeted enhanced treatment, thus leading to poor ammonia water purification efficiency.

[0007] To achieve the above objectives, the present invention provides a high-efficiency purification system for high-purity ammonia water, comprising: The purification module performs multi-stage purification of raw ammonia water to obtain high-purity ammonia water. It includes an ion exchange unit for preliminary removal of metal ions, a distillation unit for removing low-boiling-point impurities, a vacuum degassing unit for removing dissolved gases, a membrane filtration unit for retaining particulate matter and colloids, and a chelation adsorption unit for deep removal of metal ions. The data acquisition module, which is connected to the purification module, includes a first acquisition unit for acquiring the conductivity characterization value of the refined ammonia water, a second acquisition unit for acquiring the sodium ion concentration of the refined ammonia water, a third acquisition unit for acquiring the alkali consumption characterization value of the refined ammonia water, and a fourth acquisition unit for acquiring the particulate matter concentration of the finished ammonia water with a preset particle size. The control module, which is connected to the data acquisition module, is used to determine whether the purification of the refined ammonia water meets the preset standard based on the conductivity value of the refined ammonia water, to make a secondary determination whether the purification of the refined ammonia water meets the preset standard based on the sodium ion concentration of the refined ammonia water, and to determine whether the purification of the finished ammonia water meets the preset standard based on the particulate matter concentration of the finished ammonia water. The path selection module is connected to the purification module, the data acquisition module and the control module respectively, and is used to determine the purification path of the purified ammonia water under the condition that the purification does not meet the preset standard based on the alkali consumption characterization value of the purified ammonia water. An adjustment module, which is connected to the control module, is used to increase the operating pressure of the membrane filtration unit.

[0008] Furthermore, the distillation unit is located at the output end of the ion exchange unit; the output end of the distillation unit is connected to the chelation adsorption unit, the vacuum degassing unit, and the membrane filtration unit respectively; the output end of the chelation adsorption unit is connected to the vacuum degassing unit and the membrane filtration unit respectively; the output end of the vacuum degassing unit is connected to the membrane filtration unit.

[0009] Furthermore, the control module determines whether the purification of the refined ammonia water meets a preset standard based on the conductivity value of the refined ammonia water. If the conductivity value is less than the first preset conductivity value, it is determined that the purification of the refined ammonia water meets the preset standard, and the refined ammonia water is passed through the membrane filtration unit to obtain high-purity ammonia water. If the conductivity value is greater than or equal to the first preset conductivity value and less than the second preset conductivity value, it is determined that the purification of the refined ammonia water has a risk of not meeting the preset standard, and the purification of the refined ammonia water is further determined based on the sodium ion concentration of the refined ammonia water to determine whether the purification of the refined ammonia water meets the preset standard. If the conductivity characterization value is greater than or equal to the second preset conductivity characterization value, it is determined that the purification of the refined ammonia water does not meet the preset standard. The path selection module determines the purification path under the condition that the purification of the refined ammonia water does not meet the preset standard based on the alkali consumption characterization value of the refined ammonia water. The refined ammonia water is the product obtained by sequentially processing the raw ammonia water through the ion exchange unit and the distillation unit.

[0010] Further, the first acquisition unit is used to acquire the conductivity characterization value, including: Add NaOH solution dropwise to the purified ammonia water; Monitor and record the change in conductivity of the refined ammonia solution as NaOH solution is added to obtain a conductivity-volume change curve; Calculate the slope of the conductivity-volume change curve in the interval between the start of the droplet addition of NaOH solution and the point of minimum conductivity of the purified ammonia water, and record the slope as the conductivity characterization value.

[0011] Furthermore, the control module makes a secondary determination based on the sodium ion concentration of the refined ammonia water to determine whether the purification of the refined ammonia water meets the preset standard, wherein... If the sodium ion concentration is less than the preset sodium ion concentration, it is determined that the purification of the refined ammonia water meets the preset standard, and the refined ammonia water is passed through the membrane filtration unit to obtain high-purity ammonia water. If the sodium ion concentration is greater than or equal to the preset sodium ion concentration, it is determined that the purification of the refined ammonia water does not meet the preset standard, and the path selection module determines to execute the first purification path.

[0012] Furthermore, the path selection module determines the purification path for the refined ammonia water under the condition that the purification does not meet the preset standard based on the alkali consumption characterization value of the refined ammonia water, wherein, If the alkali consumption characterization value is less than the preset alkali consumption characterization value, then the second purification path is determined to be executed; If the alkali consumption characterization value is greater than or equal to the preset alkali consumption characterization value, then the third purification path is determined to be executed.

[0013] Furthermore, the third acquisition unit is used to acquire the alkali consumption characterization value of the refined ammonia water, including: The conductivity of the refined ammonia solution was measured during the dropwise addition of NaOH solution. Record the volume of alkali solution consumed when the change in conductivity of the refined ammonia water reaches a preset change amount. The ratio of the volume of alkali consumed to the preset volume of alkali consumed is recorded as the alkali consumption characterization value of the refined ammonia water.

[0014] Furthermore, the first purification path involves the refined ammonia water sequentially flowing through the chelation adsorption unit and the membrane filtration unit to obtain the finished ammonia water; The second purification path involves the refined ammonia water sequentially flowing through the vacuum degassing unit and the membrane filtration unit to obtain the finished ammonia water; The third purification path involves the refined ammonia water sequentially flowing through the chelation adsorption unit, the vacuum degassing unit, and the membrane filtration unit to obtain the finished ammonia water.

[0015] Furthermore, the control module determines whether the purification of the finished ammonia water meets a preset standard based on the particulate matter concentration of the finished ammonia water. If the particulate matter concentration is less than the preset particulate matter concentration, it is determined that the purification of the finished ammonia water meets the preset standard, and the finished ammonia water is high-purity ammonia water. If the particulate matter concentration is greater than or equal to the preset particulate matter concentration, it is determined that the purification of the finished ammonia water does not meet the preset standard, and the adjustment module increases the operating pressure of the membrane filtration unit according to the difference between the particulate matter concentration and the preset particulate matter concentration. The particulate matter concentration is the concentration of particulate matter in the finished ammonia water with a particle size greater than or equal to a preset particle size.

[0016] Furthermore, the adjustment module is equipped with several pressure adjustment methods for increasing the operating pressure of the membrane filtration unit, and each pressure adjustment method increases the operating pressure of the membrane filtration unit by a different amount.

[0017] Compared with existing technologies, the beneficial effects of this invention are that it transforms the traditional fixed purification process into an intelligent system that is decision-making and executable. Through coarse screening of conductivity characterization values, precise judgment of sodium ion concentration, grading of alkali consumption characterization values, and final judgment of particulate matter concentration, it achieves accurate identification in all dimensions. The multi-branch switchable unit connection mode allows for purification on demand, effectively avoiding energy waste and process extension caused by over-purification. At the same time, it eliminates the problem of substandard product purity caused by insufficient purification. The dynamic adjustment of the final judgment stage further ensures the stability of product purity and production continuity, thereby improving the efficiency of ammonia purification.

[0018] Furthermore, by defining flexible connection relationships between each purification unit, this invention provides diverse physical paths for material flow. This non-serial layout breaks the constraint that materials must pass through all units sequentially in the traditional process, allowing the system to intelligently and flexibly select the purification unit to flow through based on real-time diagnostic results, thereby improving system operating efficiency.

[0019] Furthermore, this invention achieves rapid initial screening and graded management of the purity of refined ammonia water by setting conductivity characterization values ​​for three-level judgment, quickly distinguishing between qualified, risky, and unqualified states, enabling rapid release of high-quality materials, key monitoring of risky materials, and targeted treatment of unqualified materials, thereby improving the accuracy of the purification process.

[0020] Furthermore, under the condition that the purification is at risk of not meeting the standard based on the conductivity characterization value, the present invention introduces sodium ion concentration for secondary judgment. Sodium ion concentration, as an indicator of the performance of the ion exchange unit, can directly determine whether the problem originates from metal ion contamination, thereby locating the ambiguous purity risk to a specific process failure, thus providing a key decision basis for subsequent path selection.

[0021] Furthermore, the present invention adopts different pressure adjustment methods for different degrees of particulate matter concentration deviation, thereby achieving precise control over the increase in operating pressure of the membrane filtration unit. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the module connection of a high-efficiency purification system for high-purity ammonia water according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating an embodiment of the present invention for determining whether the purification of the refined ammonia water meets a preset standard based on the conductivity characterization value of the refined ammonia water. Figure 3 This is a flowchart illustrating a secondary determination of whether the purification of refined ammonia water meets a preset standard based on the sodium ion concentration of the refined ammonia water according to an embodiment of the present invention. Figure 4 This is a flowchart illustrating the purification path for ammonia water under conditions where the purification does not meet preset standards, as described in this embodiment of the invention. Detailed Implementation

[0023] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0024] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0025] It should be noted that the data in this embodiment are all derived from a comprehensive analysis and evaluation of historical test data and corresponding historical test results from the three months prior to this test. Those skilled in the art will understand that the method described in this invention can determine the above-mentioned parameters in the following ways: selecting the value with the highest proportion based on the data distribution as the preset standard parameter; using weighted summation to obtain the value as the preset standard parameter; substituting each historical data point into a specific formula and using the value obtained by that formula as the preset standard parameter; or other selection methods, as long as the method described in this invention can clearly define different specific situations in the single-item judgment process through the obtained values.

[0026] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 The diagrams shown are: a module connection diagram of a high-efficiency purification system for high-purity ammonia water according to an embodiment of the present invention; a flowchart of an embodiment of the present invention for determining whether the purification of refined ammonia water meets a preset standard based on the conductivity characterization value of the refined ammonia water; a flowchart of an embodiment of the present invention for determining whether the purification of refined ammonia water meets a preset standard a second time based on the sodium ion concentration of the refined ammonia water; and a flowchart of an embodiment of the present invention for determining the purification path under the condition that the purification of refined ammonia water does not meet the preset standard.

[0027] This invention provides a high-efficiency purification system for high-purity ammonia water, comprising: The purification module performs multi-stage purification of raw ammonia water to obtain high-purity ammonia water. It includes an ion exchange unit for preliminary removal of metal ions, a distillation unit for removing low-boiling-point impurities, a vacuum degassing unit for removing dissolved gases, a membrane filtration unit for retaining particulate matter and colloids, and a chelation adsorption unit for deep removal of metal ions. The data acquisition module, which is connected to the purification module, includes a first acquisition unit for acquiring the conductivity characterization value of the refined ammonia water, a second acquisition unit for acquiring the sodium ion concentration of the refined ammonia water, a third acquisition unit for acquiring the alkali consumption characterization value of the refined ammonia water, and a fourth acquisition unit for acquiring the particulate matter concentration of the finished ammonia water with a preset particle size. The second acquisition unit is an inductively coupled plasma mass spectrometer, and the fourth acquisition unit is a laser particle counter.

[0028] The control module, which is connected to the data acquisition module, is used to determine whether the purification of the refined ammonia water meets the preset standard based on the conductivity value of the refined ammonia water, to make a secondary determination whether the purification of the refined ammonia water meets the preset standard based on the sodium ion concentration of the refined ammonia water, and to determine whether the purification of the finished ammonia water meets the preset standard based on the particulate matter concentration of the finished ammonia water. The path selection module is connected to the purification module, the data acquisition module and the control module respectively, and is used to determine the purification path of the purified ammonia water under the condition that the purification does not meet the preset standard based on the alkali consumption characterization value of the purified ammonia water. An adjustment module, which is connected to the control module, is used to increase the operating pressure of the membrane filtration unit.

[0029] Specifically, chelation adsorption is a process that utilizes the chelating effect of chelating resins on specific metal ions (a type of chemical adsorption) to achieve the deep removal of trace metal ions. The functional groups on the surface of the chelating resin (such as aminocarboxylic acid groups and phosphonic acid groups) can form stable chelates with metal ions like claws, thereby completely separating the metal ions from ammonia water.

[0030] Specifically, vacuum degassing involves placing refined ammonia water in a low-temperature (e.g., 5-15℃) and low-pressure (e.g., 0.05-0.09MPa) environment within a sealed container. Utilizing the physical principle that the solubility of gases in liquids decreases as pressure decreases, trace amounts of dissolved gases (e.g., CO2) in the ammonia water are released from the liquid as gaseous states. Then, a vacuum pump is used to extract the gaseous impurities, achieving a deep removal of trace dissolved gases.

[0031] Specifically, there are no restrictions on the specific structure of the data acquisition module, control module, path selection module, and adjustment module. They themselves and their units can be composed of logic components, including field-programmable components, computers, or microprocessors in computers.

[0032] It should be noted that the data in this embodiment are all results obtained through preliminary experiments before this test using the method described in this invention. Each preset value can be adjusted according to the specific application, as long as the method described in this invention can clearly define different specific situations in the single-item judgment process through the acquired values. The preset values ​​set in this embodiment are all obtained from preliminary experiments, including the correction coefficients, which were also selected through experimental verification.

[0033] Specifically, the distillation unit is located at the output end of the ion exchange unit; the output end of the distillation unit is connected to the chelation adsorption unit, the vacuum degassing unit, and the membrane filtration unit respectively; the output end of the chelation adsorption unit is connected to the vacuum degassing unit and the membrane filtration unit respectively; and the output end of the vacuum degassing unit is connected to the membrane filtration unit.

[0034] Specifically, the ion exchange unit uses a column packed with strong acidic cation exchange resin, with a resin loading of 20L, an operating temperature of 27℃, and a feed flow rate of 5L / h; the distillation unit uses a distillation column filled with θ-ring packing, with a top pressure of -0.09MPa, a bottom temperature of 40℃, and a reflux ratio of 3:1; the chelation adsorption unit uses an aminophosphonic acid-type chelating resin packed column, with a resin loading of 15L, an operating temperature of 25℃, and a feed flow rate of 3L / h; the vacuum degassing unit uses a vacuum degassing tank; and the membrane filtration unit uses a microfiltration membrane with a pore size of 0.1μm, an operating pressure of 0.2MPa, and a feed flow rate of 4L / h.

[0035] Specifically, the control module determines whether the purification of the refined ammonia water meets a preset standard based on the conductivity value of the refined ammonia water. If the conductivity value is less than the first preset conductivity value of 0.06 μS / (cm·mL), it is determined that the purification of the refined ammonia water meets the preset standard, and the refined ammonia water is passed through the membrane filtration unit to obtain high-purity ammonia water. If the conductivity characterization value is greater than or equal to the first preset conductivity characterization value and less than the second preset conductivity characterization value of 0.14 μS / (cm·mL), it is determined that the purification of the refined ammonia water has the risk of not meeting the preset standard, and the purification of the refined ammonia water is further determined based on the sodium ion concentration of the refined ammonia water to determine whether the purification of the refined ammonia water meets the preset standard. If the conductivity characterization value is greater than or equal to the second preset conductivity characterization value, it is determined that the purification of the refined ammonia water does not meet the preset standard. The path selection module determines the purification path under the condition that the purification of the refined ammonia water does not meet the preset standard based on the alkali consumption characterization value of the refined ammonia water. The refined ammonia water is the product obtained by sequentially processing the raw ammonia water through the ion exchange unit and the distillation unit.

[0036] Specifically, the first preset conductivity value ranges from [0.04 μS / (cm·mL), 0.08 μS / (cm·mL)] to [0.12 μS / (cm·mL), 0.16 μS / (cm·mL)]. Preferably, the first preset conductivity value is 0.06 μS / (cm·mL) and the second preset conductivity value is 0.14 μS / (cm·mL).

[0037] Specifically, the conductivity value characterizes the total amount and reaction rate of active impurities in refined ammonia water that can react with external hydroxide ions. In other words, it characterizes the ability of refined ammonia water to resist pH changes and consume alkali solution, i.e., the dynamic chemical stability of refined ammonia water.

[0038] Specifically, the three-level judgment method based on conductivity characterization values ​​monitors the response slope of the added alkali solution, sensitively amplifies the signals of metal ions and dissolved gases, and quickly classifies materials into three levels: qualified, risky, and unqualified. This triggers three differentiated follow-up processes: direct release, precise secondary judgment, and targeted in-depth treatment, ensuring that problematic materials can be treated in a targeted manner. Ultimately, this improves purification efficiency while ensuring product quality.

[0039] Specifically, the first acquisition unit is used to acquire the conductivity characterization value, including: A 50 mL sample of purified ammonia was taken from the outlet of the distillation unit and transferred to a 25°C constant temperature sample cell. A 0.01 mol / L NaOH solution was added dropwise to the purified ammonia sample at a titration rate of 0.5 mL / min. The conductivity of the purified ammonia water sample was monitored synchronously using a conductivity meter, and the change in conductivity with the volume of NaOH added was recorded in real time. The conductivity-volume change curve was plotted. Calculate the slope of the interval from the titration start point to the minimum conductivity of the refined ammonia solution, and record the slope as the conductivity characterization value of the refined ammonia solution.

[0040] Specifically, the control module makes a secondary determination based on the sodium ion concentration of the refined ammonia water to determine whether the purification of the refined ammonia water meets the preset standard, wherein... If the sodium ion concentration is less than the preset sodium ion concentration of 0.08 ppb, it is determined that the purification of the refined ammonia water meets the preset standard, and the refined ammonia water is passed through the membrane filtration unit to obtain high-purity ammonia water. If the sodium ion concentration is greater than or equal to the preset sodium ion concentration, it is determined that the purification of the refined ammonia water does not meet the preset standard, and the path selection module determines to execute the first purification path.

[0041] In this embodiment, the preset sodium ion concentration is 0.08 ppb, but the above value is not limited to this. Those skilled in the art can adjust the above value according to actual needs.

[0042] Specifically, sodium ion concentration is introduced for secondary judgment when the conductivity characterization value is within the critical range. The selection of sodium ion concentration as the core indicator for secondary judgment is based on its special role in electronic-grade high-purity ammonia: on the one hand, due to its small radius and strong penetrability, sodium ions are the most easily missed metal ions in the preceding ion exchange unit, and their risk of exceeding the standard is higher than other heavy metal ions; on the other hand, sodium ions are significantly harmful in semiconductor manufacturing, easily migrating to the wafer surface to form conductive channels, leading to a decrease in device insulation performance, making it a key metal impurity that must be strictly controlled in electronic-grade ammonia. After coarse screening based on conductivity characterization values, sodium ion concentration is introduced within the critical range for precise judgment. This avoids the limitations of a single characterization method and ensures the targeted selection of subsequent purification paths. Only when the sodium ion concentration exceeds the standard is the first purification path, centered on chelation adsorption, initiated; otherwise, it directly enters the membrane filtration unit, thereby improving purification efficiency.

[0043] Specifically, the path selection module determines the purification path for the refined ammonia water under the condition that the purification does not meet the preset standard based on the alkali consumption characterization value of the refined ammonia water. If the alkali consumption characterization value is less than the preset alkali consumption characterization value of 1.4, then the second purification path will be executed. If the alkali consumption characterization value is greater than or equal to the preset alkali consumption characterization value, then the third purification path is determined to be executed.

[0044] Specifically, the alkali consumption index quantifies the total amount and intensity of acidic impurities in refined ammonia water that can react with external OH- ions. In this embodiment, these impurities mainly refer to dissolved CO2 and its derived carbonate and bicarbonate ions. A higher alkali consumption index not only means a higher total amount of acidic impurities in the refined ammonia water, but also indicates that more carbonate ions that are difficult to remove through physical degassing may have been generated in the refined ammonia water, thus requiring more intensive chemical treatment.

[0045] Specifically, the preset alkali consumption characterization value is 1.4. Titration tests and data analysis were performed on 50 ammonia water samples with known impurity components and concentrations. All samples whose CO2 concentration exceeded the standard (i.e., CO2 concentration greater than 50 ppb) were confirmed by gas chromatography. Their alkali consumption characterization values ​​were consistently above 1.5. However, the above value is not limited to this. Those skilled in the art can adjust the above value according to actual needs.

[0046] Specifically, the third acquisition unit is used to acquire the alkali consumption characterization value of the refined ammonia water, including: During the process of adding NaOH solution dropwise to the refined ammonia water, the conductivity of the refined ammonia water was continuously monitored using a conductivity meter; Record the volume of alkali solution consumed when the change in conductivity of the refined ammonia water reaches a preset change of 1.0 μS / cm; The ratio of the volume of alkali consumed to the preset volume of alkali consumed (0.2 mL) is recorded as the alkali consumption characterization value of the refined ammonia water.

[0047] Specifically, the first purification path involves the refined ammonia water flowing sequentially through the chelation adsorption unit and the membrane filtration unit to obtain the finished ammonia water. The second purification path involves the refined ammonia water sequentially flowing through the vacuum degassing unit and the membrane filtration unit to obtain the finished ammonia water; The third purification path involves the refined ammonia water sequentially flowing through the chelation adsorption unit, the vacuum degassing unit, and the membrane filtration unit to obtain the finished ammonia water.

[0048] Specifically, the control module drives electric valves to achieve directional flow of refined ammonia water between the chelation adsorption unit, the vacuum degassing unit, and the membrane filtration unit.

[0049] Specifically, a first control valve, a second control valve, and a third control valve are connected in parallel at the outlet of the distillation unit, respectively connected to the inlet of the chelation adsorption unit, the inlet of the vacuum degassing unit, and the inlet of the membrane filtration unit; a fourth control valve and a fifth control valve are connected in parallel at the outlet of the chelation adsorption unit, respectively connected to the inlet of the vacuum degassing unit and the inlet of the membrane filtration unit; and a sixth control valve is connected at the outlet of the vacuum degassing unit to the inlet of the membrane filtration unit. All valves are ammonia-resistant electric ball valves.

[0050] In this embodiment, when the first purification path is executed, the control module opens the first control valve and the fifth control valve, and closes the other control valves, so that the refined ammonia water flows directly into the membrane filtration unit after passing through the chelation adsorption unit. When the second purification path is executed, the control module opens the second control valve and the first flow control valve, and closes the other control valves, so that the refined ammonia water flows through the vacuum degassing unit and then enters the membrane filtration unit. When the third purification path is executed, the control module opens the first control valve, the fourth control valve, and the sixth control valve, and closes the remaining control valves, so that the refined ammonia water flows sequentially through the chelation adsorption unit, the vacuum degassing unit, and the membrane filtration unit.

[0051] Specifically, the control module determines whether the purification of the finished ammonia solution meets a preset standard based on the particulate matter concentration of the finished ammonia solution. If the particulate matter concentration is less than the preset particulate matter concentration of 25 particles / mL, then the purification of the finished ammonia water is determined to meet the preset standard, and the finished ammonia water is high-purity ammonia water. If the particulate matter concentration is greater than or equal to the preset particulate matter concentration, it is determined that the purification of the finished ammonia water does not meet the preset standard, and the adjustment module increases the operating pressure of the membrane filtration unit according to the difference between the particulate matter concentration and the preset particulate matter concentration. The particulate matter concentration is the concentration of particulate matter in the finished ammonia water with a particle size greater than or equal to a preset particle size of 0.1 μm.

[0052] In this embodiment, statistical analysis of data from 100 qualified finished ammonia solutions showed that the particulate matter concentration of the qualified finished ammonia solutions was less than 20 particles / mL. Therefore, the preset particulate matter concentration was 25 particles / mL. However, the above value is not limited to this, and those skilled in the art can adjust the above value according to actual needs.

[0053] Specifically, the adjustment module has several pressure adjustment methods for responding to increases in the operating pressure of the membrane filtration unit, wherein, If the particulate matter concentration deviation is less than the first preset concentration deviation value of 4 particles / mL, the operating pressure of the membrane filtration unit is increased to the corresponding value using the first adjustment coefficient of 1.03. If the particulate matter concentration deviation is greater than or equal to the first preset concentration deviation and less than the second preset concentration deviation of 9 particles / mL, then the operating pressure of the membrane filtration unit is increased to the corresponding value using the second adjustment coefficient of 1.06. If the particulate matter concentration deviation is greater than or equal to the second preset concentration deviation, the operating pressure of the membrane filtration unit is increased to the corresponding value using a third adjustment coefficient of 1.09. The particulate matter concentration deviation value is the difference between the particulate matter concentration and the preset particulate matter concentration, as determined by the adjustment module.

[0054] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high efficiency purification system for high purity aqueous ammonia, characterized by, The application relates to a high-purity ammonia water production system, which comprises: a purification module for multi-stage purification of raw ammonia water to obtain high-purity ammonia water, which comprises an ion exchange unit for preliminary removal of metal ions, a rectification unit for removal of low-boiling impurities, a vacuum degassing unit for removal of soluble gases, a membrane filtration unit for interception of particulate matter and colloids, and a chelation adsorption unit for deep removal of metal ions; a data acquisition module connected with the purification module, which comprises a first acquisition unit for acquisition of the conductance characteristic value of refined ammonia water, a second acquisition unit for acquisition of the sodium ion concentration of refined ammonia water, a third acquisition unit for acquisition of the caustic consumption characteristic value of refined ammonia water, and a fourth acquisition unit for acquisition of the particulate matter concentration of product ammonia water with a preset particle size; a control module connected with the data acquisition module, which is used for determining whether the purification of refined ammonia water meets preset standards according to the conductance characteristic value of the refined ammonia water, for secondarily determining whether the purification of refined ammonia water meets preset standards according to the sodium ion concentration of the refined ammonia water, and for determining whether the purification of product ammonia water meets preset standards according to the particulate matter concentration of the product ammonia water; a path selection module connected with the purification module, the data acquisition module and the control module respectively, which is used for determining the purification path of refined ammonia water under the condition that the purification of refined ammonia water does not meet preset standards according to the caustic consumption characteristic value of the refined ammonia water; an adjustment module connected with the control module, which is used for increasing the operating pressure of the membrane filtration unit.

2. The high efficiency purification system for high purity aqueous ammonia according to claim 1, characterized by, The rectification unit is arranged at the output end of the ion exchange unit; the output end of the rectification unit is connected with the chelation adsorption unit, the vacuum degassing unit and the membrane filtration unit respectively; the output end of the chelation adsorption unit is connected with the vacuum degassing unit and the membrane filtration unit respectively; and the output end of the vacuum degassing unit is connected with the membrane filtration unit.

3. The high efficiency purification system for high purity aqueous ammonia according to claim 2, characterized by, The control module determines whether the purification of refined ammonia water meets preset standards according to the conductance characteristic value of the refined ammonia water, wherein, if the conductance characteristic value is less than a first preset conductance characteristic value, it is determined that the purification of refined ammonia water meets preset standards, and the refined ammonia water is subjected to the membrane filtration unit to obtain high-purity ammonia water; if the conductance characteristic value is greater than or equal to the first preset conductance characteristic value and less than a second preset conductance characteristic value, it is determined that the purification of refined ammonia water has the risk of not meeting preset standards, and it is secondarily determined whether the purification of refined ammonia water meets preset standards according to the sodium ion concentration of the refined ammonia water; if the conductance characteristic value is greater than or equal to the second preset conductance characteristic value, it is determined that the purification of refined ammonia water does not meet preset standards, and the path selection module determines the purification path of refined ammonia water under the condition that the purification of refined ammonia water does not meet preset standards according to the caustic consumption characteristic value of the refined ammonia water; The refined ammonia water is the product obtained after the raw ammonia water is sequentially subjected to the ion exchange unit and the rectification unit.

4. The high efficiency purification system for high purity aqueous ammonia according to claim 3, characterized by, The first acquisition unit for acquisition of the conductance characteristic value comprises: dropping NaOH solution into the refined ammonia water; monitoring and recording the change of the conductivity of the refined ammonia water with the dropping of NaOH solution to obtain a conductivity-volume change curve; The slope of the interval between the minimum point of the conductivity of the refined ammonia water and the start of the NaOH solution dropping to the refined ammonia water is calculated, and the slope is recorded as a conductivity characterization value.

5. The high efficiency purification system for high purity aqueous ammonia according to claim 4, characterized by, The control module determines whether the purification of the refined ammonia water meets the preset standard according to the sodium ion concentration of the refined ammonia water, wherein, if the sodium ion concentration is less than a preset sodium ion concentration, it is determined that the purification of the refined ammonia water meets the preset standard, and the refined ammonia water is filtered through the membrane filtration unit to obtain high-purity ammonia water; if the sodium ion concentration is greater than or equal to the preset sodium ion concentration, it is determined that the purification of the refined ammonia water does not meet the preset standard, and the path selection module determines to execute a first purification path.

6. The high efficiency purification system for high purity aqueous ammonia according to claim 5, characterized by, The path selection module determines the purification path of the refined ammonia water when the purification of the refined ammonia water does not meet the preset standard according to the alkali consumption characterization value of the refined ammonia water, wherein, if the alkali consumption characterization value is less than a preset alkali consumption characterization value, the second purification path is determined to be executed; if the alkali consumption characterization value is greater than or equal to the preset alkali consumption characterization value, the third purification path is determined to be executed.

7. The high efficiency purification system for high purity aqueous ammonia according to claim 6, characterized by, The third acquisition unit is configured to acquire the alkali consumption characterization value of the refined ammonia water, comprising: detecting the conductivity of the refined ammonia water during the process of dropping the NaOH solution to the refined ammonia water; recording the alkali consumption volume corresponding to the change amount of the conductivity of the refined ammonia water reaching a preset change amount; the ratio of the alkali consumption volume to a preset alkali consumption volume is recorded as the alkali consumption characterization value of the refined ammonia water.

8. The high efficiency purification system for high purity aqueous ammonia according to claim 7, characterized by, The first purification path is that the refined ammonia water flows through the chelate adsorption unit and the membrane filtration unit in sequence to obtain finished ammonia water. The second purification path is that the refined ammonia water flows through the vacuum degassing unit and the membrane filtration unit in sequence to obtain finished ammonia water. The third purification path is that the refined ammonia water flows through the chelate adsorption unit, the vacuum degassing unit and the membrane filtration unit in sequence to obtain finished ammonia water.

9. The high efficiency purification system for high purity aqueous ammonia according to claim 8, characterized by, The control module determines whether the purification of the finished ammonia water meets the preset standard according to the particulate matter concentration of the finished ammonia water, wherein, if the particulate matter concentration is less than a preset particulate matter concentration, it is determined that the purification of the finished ammonia water meets the preset standard, and the finished ammonia water is high-purity ammonia water; if the particulate matter concentration is greater than or equal to the preset particulate matter concentration, it is determined that the purification of the finished ammonia water does not meet the preset standard, and the adjustment module increases the operating pressure of the membrane filtration unit according to the difference between the particulate matter concentration and the preset particulate matter concentration; The particulate matter concentration is the concentration of particulate matter with a particle size greater than or equal to a preset particle size in the finished ammonia water.

10. The high efficiency purification system for high purity aqueous ammonia according to claim 9, characterized in that, The adjustment module is provided with several pressure adjustment modes for the increase of the operating pressure of the membrane filtration unit, and each pressure adjustment mode has a different increase range of the operating pressure of the membrane filtration unit.

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