Electronic grade ultra-high purity ammonia water gradient purification method and system

Abstract

This invention discloses a gradient purification method and system for electronic-grade ultra-high purity ammonia. The method involves real-time detection of oxygen, hydrogen, metal ion, and moisture concentrations in green ammonia raw materials using online mass spectrometry coupled with gas chromatography, and dynamic adjustment of process parameters based on the detection results. The raw materials are sequentially passed through a catalytic hydrogenation unit, a three-stage adsorption unit, a single-stage distillation unit, and a terminal polishing unit for gradient purification. An oxygen concentration threshold response mechanism is set: when oxygen > 1 ppm, the catalytic hydrogenation temperature is increased to 170℃ and the adsorption cycle is shortened to 12 hours; when oxygen < 1 ppm, the catalytic hydrogenation temperature is maintained at 150℃ and the adsorption cycle is maintained at 24 hours. This invention also provides a gradient purification system for implementing this method. This invention achieves stable production of electronic-grade ammonia with metal ion content ≤ 0.009 ppt, particulate matter concentration ≤ 0.8 particles / mL, and purity 7N+, reducing energy consumption by 42.9% and increasing raw material utilization by 16%, and can replace imported high-purity ammonia.

Description

Technical Field

[0001] This invention relates to a gradient purification method and system for electronic-grade ultra-high purity ammonia water, belonging to the field of electronic chemical preparation technology. Background Technology

[0002] As the semiconductor industry moves towards advanced processes of 3 nanometers and below, electronic-grade ammonia, a core wet electronic chemical in key processes such as wafer cleaning and etching, has seen its purity requirements rise from the traditional 6N (99.9999%) to the 7N (99.99999%) level. Currently, the mainstream production process for electronic-grade ammonia is based on multi-stage distillation and adsorption purification of industrial ammonia. This technology is relatively mature in processing traditional industrial ammonia and can achieve a purity of 6N.

[0003] However, with the large-scale application of the "green electricity-electrolysis of water-synthetic ammonia" pathway, green ammonia has entered the field of electronic-grade ammonia production as a novel raw material. Green ammonia raw materials have a unique impurity profile, including trace oxygen (0.1-5 ppm), residual hydrogen (0.05-2%), metal catalyst particles (0.01-0.5 ppb as Fe³⁺), and moisture, etc. Existing purification processes have the following technical shortcomings: First, the process and impurity profile are mismatched. Traditional multi-stage distillation processes are not designed for the unique impurity combination of green ammonia, and cannot efficiently convert oxygen impurities, requiring additional distillation steps, resulting in an increase in energy consumption of more than 30%. Metal catalyst residues and moisture are difficult to remove, and the metal ion content of the product cannot be stably kept below 5ppt, with a purity of only 6N.

[0004] Second, it cannot adapt to fluctuations in raw material impurities. Green ammonia production is affected by fluctuations in green electricity, and its impurity concentration exhibits dynamic changes. Existing fixed-parameter processes cannot achieve precise matching between impurities and process parameters.

[0005] Third, it has high energy consumption and low raw material utilization. The energy consumption per unit product is as high as 4.0-4.2 kWh / kg, and the raw material ammonia consumption is 1.2 tons / ton of product, which is far higher than the industry ideal value.

[0006] Fourth, China's semiconductor industry has long relied on imports of high-purity ammonia from companies such as BASF and Mitsubishi Gas, and a breakthrough in developing an independent supply chain is urgently needed.

[0007] While existing publicly available technologies involve ammonia purification, they are still based on the impurity profile of industrial ammonia and do not optimize the process for the unique impurity combination of green ammonia feedstock, thus failing to solve the aforementioned technical problems. Therefore, developing an electronic-grade ammonia purification method and system that can accurately match the unique impurity profile of green ammonia feedstock, achieve stable production of 7N purity, and possess low energy consumption and high yield characteristics is a technical challenge that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] This invention aims to solve the technical problems in the prior art, such as the mismatch between the unique impurity profile of green ammonia raw materials and the purification process, the difficulty in achieving product purity of 7N, high energy consumption, and low raw material utilization. It provides an electronic-grade ultra-high purity ammonia purification method and system that can dynamically respond to fluctuations in green ammonia impurities and achieve gradient precision purification.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A gradient purification method for electronic-grade ultra-high purity ammonia water includes the following steps: S1. Obtain green ammonia raw material, and use an online mass spectrometer and gas chromatography-coupled device to detect the impurity spectrum in the green ammonia raw material in real time. The impurity spectrum includes at least the concentrations of oxygen, hydrogen, metal ions and water. S2. Based on the detected impurity spectrum, dynamically adjust the purification process parameters; S3. The green ammonia raw material is sequentially passed through a catalytic hydrogenation unit, a three-stage adsorption unit, a single-stage distillation unit and a terminal polishing unit for gradient purification to obtain electronic-grade ultra-high purity ammonia water with a metal ion content ≤0.009ppt, a particulate matter concentration ≤0.8 particles / mL and a purity of 7N+. S4. When the detected oxygen concentration is higher than 1 ppm, the reaction temperature of the catalytic hydrogenation unit is increased to 170°C and the adsorbent switching cycle is shortened to 12 hours; when the oxygen concentration is lower than 1 ppm, the reaction temperature of the catalytic hydrogenation unit is maintained at 150°C and the adsorbent switching cycle is maintained at 24 hours.

[0010] As a preferred embodiment of the present invention, the catalytic hydrogenation unit uses a Pd-Pt / TiO2 bimetallic catalyst and reacts at a pressure of 2.0 MPa for 90-120 minutes to completely convert oxygen into water; the Pd-Pt / TiO2 bimetallic catalyst has a Pd loading of 0.5 wt% and a Pt loading of 0.3 wt%.

[0011] As a preferred embodiment of the present invention, the three-stage adsorption unit includes: First-stage adsorption: Using 3A molecular sieve, operating at a constant temperature of -15℃, the moisture content is controlled to 10ppb; Second-stage adsorption: Using a nickel-based catalyst, the oxygen residue was reduced to 0.5 ppb by operating at a constant temperature of 10℃. Third-stage adsorption: A composite adsorbent with a silica gel to activated carbon mass ratio of 3:1 was used and operated at a constant temperature of 20℃ to stabilize the heavy metal ion concentration at 0.1 ppb.

[0012] As a preferred embodiment of the present invention, the single-stage distillation unit adopts a structured packed column, the operating pressure is strictly maintained at 0.8 MPa, the top temperature is precisely controlled at -50°C, and the bottom temperature is precisely controlled at 35°C.

[0013] As a preferred embodiment of the present invention, the terminal polishing unit sequentially includes a chelating resin ion exchanger and a PTFE membrane filter with a pore size of 0.05 μm. After treatment, the metal ion concentration is stabilized at 0.007-0.009 ppt, and the particulate matter concentration is 0.6-0.8 particles / mL.

[0014] As a preferred embodiment of the present invention, the method further includes 100% recovery of the cooling capacity of the distillation column top condenser at -50°C and its use for precooling of the adsorption unit, and the use of a heat pump system to replace electric heating; the overall energy consumption of gradient purification is 2.3-2.5 kWh / kg, the ammonia recovery rate reaches 99.999%, and the raw material ammonia consumption is 1.02 tons / ton of product.

[0015] An electronic-grade ultra-high purity ammonia gradient purification system for implementing the above method includes: The impurity detection unit, consisting of an online mass spectrometer and a gas chromatograph, is used to detect the impurity spectrum in green ammonia raw materials in real time. The control unit is connected to the impurity detection unit and is used to dynamically adjust the operating parameters of subsequent units according to the impurity spectrum. The catalytic hydrogenation unit, connected to the control unit, is filled with a Pd-Pt / TiO2 bimetallic catalyst to convert oxygen in the green ammonia feedstock into water. The three-stage adsorption unit, connected to the outlet of the catalytic hydrogenation unit, includes a first-stage 3A molecular sieve adsorber, a second-stage nickel-based catalyst adsorber, and a third-stage silica gel-activated carbon composite adsorber connected in series, for removing moisture, residual oxygen, and heavy metal ions. The single-stage distillation unit is connected to the outlet of the three-stage adsorption unit and is a structured packed distillation column with an operating pressure of 0.8 MPa, a top temperature of -50°C, and a bottom temperature of 35°C. The terminal polishing unit, connected to the outlet of the single-stage distillation unit, includes a chelating resin ion exchanger and a PTFE membrane filter with a pore size of 0.05 μm connected in series.

[0016] As a preferred embodiment of the present invention, the catalytic hydrogenation unit is further provided with a temperature regulation device and an adsorbent switching device. When the impurity detection unit detects an oxygen concentration >1 ppm, the control unit instructs the temperature regulation device to raise the reaction temperature to 170°C and shorten the adsorbent switching cycle to 12 hours. When the oxygen concentration <1 ppm, the control unit instructs the temperature regulation device to maintain the reaction temperature at 150°C and maintain the adsorbent switching cycle at 24 hours.

[0017] As a preferred embodiment of the present invention, the top condenser of the single-stage distillation unit is connected to the precooling device of the three-stage adsorption unit through a cold energy recovery pipeline, for 100% recovery and utilization of the -50℃ cold energy; the bottom of the single-stage distillation unit is heated by a heat pump system.

[0018] As a preferred embodiment of the present invention, the impurity spectrum detected by the impurity detection unit includes at least oxygen 0.1-5 ppm, hydrogen 0.05-2%, iron ions 0.01-0.5 ppb, and moisture.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects: The product of this invention has a stable metal ion content of 0.007-0.009 ppt, which is 99.8% lower than the 3.2-4.8 ppt of the traditional process; a particulate matter concentration of 0.6-0.8 particles / mL, which is 81-82.7% lower than the 3.5-4.2 particles / mL of the traditional process; and a purity of 7N+ (99.99999%+), while the traditional process can only reach 6N (99.9999%), meeting the requirements of advanced processes of 3 nanometers and below.

[0020] This invention integrates a dynamic response gradient purification system and green processes such as 100% cold energy recovery and heat pump replacement of electric heating. The energy consumption per unit product of this invention is reduced to 2.3-2.5 kWh / kg, which is 42.9% lower than the traditional process of 4.0-4.2 kWh / kg. At the same time, the ammonia recovery rate of this invention reaches 99.999%, which is 4.499-4.999 percentage points higher than the traditional process of 95-95.5%. The raw material ammonia consumption is reduced from 1.2 tons / ton of product to 1.02 tons / ton of product, and the raw material utilization rate is increased by 16%.

[0021] This invention is based on the quantification and mapping mechanism of the unique impurity spectrum of green ammonia feedstock. When the oxygen concentration is >1ppm, a high temperature / short cycle mode is automatically triggered, and when the oxygen concentration is <1ppm, a low temperature / long cycle mode is maintained. This avoids the inefficient process of adding an additional distillation step in the traditional process and solves the core technical problem of the mismatch between the impurity fluctuation of green ammonia feedstock and the fixed parameter process.

[0022] This invention constructs an integrated system of "catalytic hydrogenation-three-stage adsorption-single-stage distillation-terminal polishing". By optimizing the process parameters, it achieves stable production with a purity of 7N+, breaking through the limitation of traditional multi-stage distillation processes that only achieve a purity of 6N.

[0023] This invention utilizes a distillation column top condenser with 100% recovery of -50℃ cold energy for precooling the adsorption unit, and a heat pump system to replace electric heating, achieving efficient synergy between energy and production, and meeting the needs of large-scale production of green electronic chemicals under the "dual carbon" target.

[0024] This invention directly solves the problem of the domestic semiconductor industry's reliance on imported high-purity ammonia, supports an increase in product gross profit margin from 40% to 55%, and provides key technical support for the security of my country's semiconductor industry chain. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the electronic-grade ultra-high purity ammonia gradient purification system in an embodiment of the present invention.

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0027] This invention addresses the core problem in existing technologies where the "unique impurity profile of green ammonia feedstock is mismatched with the purification process," solving the technical bottleneck that traditional industrial ammonia purification processes cannot adapt to the unique impurity combination of green ammonia feedstock. Existing technologies (such as traditional multi-stage distillation processes) fail to consider the unique impurity profile of green ammonia (O2 0.1-5ppm, Fe³⁺ 0.01-0.5ppb, H2 0.05-2%) generated by the "green electricity-electrolysis of water-synthetic ammonia" pathway. This leads to several technical defects in practical applications, including inefficient conversion of oxygen impurities (requiring an additional distillation step, increasing energy consumption by more than 30%), ineffective removal of residual metal catalysts and moisture (making it difficult to stabilize the metal ion content of the product below 5ppt), a purity of only 6N (99.9999%) which cannot meet the 7N (99.99999%) semiconductor-grade requirements, and low raw material utilization (1.2 tons / ton).

[0028] In view of the technical defects of existing technologies, such as the mismatch between the unique impurity spectrum of green ammonia raw materials and the purification process, the difficulty in achieving product purity of 7N, high energy consumption, and low raw material utilization, this invention proposes a technical solution to solve the above problems.

[0029] In a first aspect, the present invention provides a gradient purification method for electronic-grade ultra-high purity ammonia water, comprising the following steps: S1. Obtain green ammonia raw material, and use an online mass spectrometer and gas chromatography-coupled device to detect the impurity spectrum in the green ammonia raw material in real time. The impurity spectrum includes at least the concentrations of oxygen, hydrogen, metal ions and water. S2. Based on the detected impurity spectrum, dynamically adjust the purification process parameters; S3. The green ammonia raw material is sequentially passed through a catalytic hydrogenation unit, a three-stage adsorption unit, a single-stage distillation unit and a terminal polishing unit for gradient purification to obtain electronic-grade ultra-high purity ammonia water with a metal ion content ≤0.009ppt, a particulate matter concentration ≤0.8 particles / mL and a purity of 7N+. S4. When the detected oxygen concentration is higher than 1 ppm, the reaction temperature of the catalytic hydrogenation unit is increased to 170°C and the adsorbent switching cycle is shortened to 12 hours; when the oxygen concentration is lower than 1 ppm, the reaction temperature of the catalytic hydrogenation unit is maintained at 150°C and the adsorbent switching cycle is maintained at 24 hours.

[0030] Specifically, the catalytic hydrogenation unit uses a Pd-Pt / TiO2 bimetallic catalyst and reacts at a pressure of 2.0 MPa for 90-120 minutes to completely convert oxygen into water; the Pd-Pt / TiO2 bimetallic catalyst has a Pd loading of 0.5 wt% and a Pt loading of 0.3 wt%.

[0031] Specifically, the tertiary adsorption unit includes: First-stage adsorption: Using 3A molecular sieve, operating at a constant temperature of -15℃, the moisture content is controlled to 10ppb; Second-stage adsorption: Using a nickel-based catalyst, the oxygen residue was reduced to 0.5 ppb by operating at a constant temperature of 10℃. Third-stage adsorption: A composite adsorbent with a silica gel to activated carbon mass ratio of 3:1 was used and operated at a constant temperature of 20℃ to stabilize the heavy metal ion concentration at 0.1 ppb.

[0032] Specifically, the single-stage distillation unit uses a structured packed column, with the operating pressure strictly maintained at 0.8 MPa, the top temperature precisely controlled at -50°C, and the bottom temperature precisely controlled at 35°C.

[0033] Specifically, the terminal polishing unit includes a chelating resin ion exchanger and a PTFE membrane filter with a pore size of 0.05 μm. After treatment, the metal ion concentration is stabilized at 0.007-0.009 ppt and the particulate matter concentration is 0.6-0.8 particles / mL.

[0034] Specifically, the method also includes 100% recovery of the -50°C cooling capacity of the distillation column top condenser for precooling the adsorption unit, and the use of a heat pump system to replace electric heating; the overall energy consumption of gradient purification is 2.3-2.5 kWh / kg, the ammonia recovery rate is 99.999%, and the raw material ammonia consumption is 1.02 tons / ton of product.

[0035] In a second aspect, the present invention provides an electronic-grade ultra-high purity ammonia gradient purification system for implementing the above-described method, comprising: The impurity detection unit, consisting of an online mass spectrometer and a gas chromatograph, is used to detect the impurity spectrum in green ammonia raw materials in real time. The control unit is connected to the impurity detection unit and is used to dynamically adjust the operating parameters of subsequent units according to the impurity spectrum. The catalytic hydrogenation unit, connected to the control unit, is filled with a Pd-Pt / TiO2 bimetallic catalyst to convert oxygen in the green ammonia feedstock into water. The three-stage adsorption unit, connected to the outlet of the catalytic hydrogenation unit, includes a first-stage 3A molecular sieve adsorber, a second-stage nickel-based catalyst adsorber, and a third-stage silica gel-activated carbon composite adsorber connected in series, for removing moisture, residual oxygen, and heavy metal ions. The single-stage distillation unit is connected to the outlet of the three-stage adsorption unit and is a structured packed distillation column with an operating pressure of 0.8 MPa, a top temperature of -50°C, and a bottom temperature of 35°C. The terminal polishing unit, connected to the outlet of the single-stage distillation unit, includes a chelating resin ion exchanger and a PTFE membrane filter with a pore size of 0.05 μm connected in series.

[0036] Specifically, the catalytic hydrogenation unit is also equipped with a temperature regulation device and an adsorbent switching device. When the impurity detection unit detects an oxygen concentration >1 ppm, the control unit instructs the temperature regulation device to raise the reaction temperature to 170°C and shorten the adsorbent switching cycle to 12 hours. When the oxygen concentration <1 ppm, the control unit instructs the temperature regulation device to maintain the reaction temperature at 150°C and maintain the adsorbent switching cycle at 24 hours.

[0037] Specifically, the overhead condenser of the single-stage distillation unit is connected to the precooling device of the three-stage adsorption unit through a cold energy recovery pipeline, which is used to recover and reuse 100% of the -50℃ cold energy; the bottom of the single-stage distillation unit is heated by a heat pump system.

[0038] Specifically, the impurity spectrum detected by the impurity detection unit includes at least oxygen (0.1-5 ppm), hydrogen (0.05-2%), iron ions (0.01-0.5 ppb), and moisture.

[0039] This invention establishes a dynamic response relationship between impurity concentration and process parameters through a quantification and mapping mechanism based on the "unique impurity profile of green ammonia feedstock." This enables precise control of key parameters such as catalytic hydrogenation temperature (150-170℃) and adsorption cycle (12-24h), avoiding the inefficient process of adding a distillation step required by traditional methods. Simultaneously, it innovatively constructs a four-stage purification system consisting of catalytic hydrogenation, three-stage adsorption, single-stage distillation, and terminal polishing. By optimizing process parameters, the metal ion content is stabilized at 0.007-0.009 ppt, the particulate matter concentration at 0.6-0.8 particles / mL, the ammonia recovery rate at 99.999%, energy consumption reduced to 2.3-2.5 kWh / kg, and feedstock utilization increased to 1.02 tons / ton. This technology can be directly applied to the production of semiconductor electronic chemicals, solving the problem of reliance on imports in the domestic semiconductor industry. It achieves stable production of 7N purity while reducing energy consumption by 42% and increasing feedstock utilization by 16%, providing the semiconductor industry with a self-reliant and controllable green electronic chemical solution.

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific application and experimental embodiments. Those skilled in the art should understand that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0041] Unless otherwise specified in the examples, the conditions shall be performed in accordance with conventional conditions or the conditions recommended by the manufacturer; unless the manufacturer of the reagents or instruments used is specified, they are all conventional products that can be purchased commercially.

[0042] This invention establishes an electronic-grade ammonia purification process model based on Aspen Plus software, and verifies gradient purification for typical green ammonia raw materials (O2 1.2ppm, Fe³⁺ 0.2ppb, H2 0.5%).

[0043] The catalytic hydrogenation unit uses a Pd-Pt / TiO2 bimetallic catalyst (Pd content 0.5wt%, Pt content 0.3wt%), and reacts for 120 minutes at a precise temperature of 150℃ and a pressure of 2.0MPa to completely convert oxygen into water molecules.

[0044] The system then enters a three-stage adsorption system. The first stage, 3A molecular sieve, operates at a constant temperature of -15℃ to precisely control the moisture content at 10ppb. The second stage, nickel-based catalyst, operates at a constant temperature of 10℃ to precisely reduce the residual oxygen content to 0.5ppb. The third stage, composite adsorbent (silica gel and activated carbon in a mass ratio of 3:1), operates at a constant temperature of 20℃ to stabilize the heavy metal ion concentration at 0.1ppb.

[0045] The distillation unit uses a structured packed column, with the operating pressure strictly maintained at 0.8 MPa and the top temperature precisely controlled at -50℃ to achieve efficient recovery of light components. The bottom temperature is precisely controlled at 35℃ to prevent the decomposition of heat-sensitive impurities through falling film evaporation technology.

[0046] The terminal processing unit sequentially passes the ion exchange with chelating resin (metal ion concentration stabilized at 0.008 ppt), filtration through a 0.05 μm pore size PTFE membrane (particulate matter concentration 0.8 particles / mL), and precise dilution with ultrapure water to a concentration of 29.6%.

[0047] Simulation results show that the product has a metal ion content of 0.008 ppt, a particulate matter concentration of 0.8 particles / mL, an ammonia recovery rate of 99.999%, and an energy consumption of 2.4 kWh / kg. All indicators are significantly better than the SEMI C8 standard (metal <5 ppt, particles <5 particles / mL).

[0048] This embodiment, through the optimization of process parameter settings (such as temperature 150℃, pressure 2.0MPa, time 120 minutes), and the clear technical differences from the traditional multi-stage distillation process (energy consumption 4.2kWh / kg, metal ion concentration 3.2ppt), fully demonstrates the innovative breakthrough of this invention in three dimensions: purity improvement (7N+ vs 6N), energy consumption reduction (42.9%), and raw material utilization rate (1.02 tons / ton vs 1.2 tons / ton).

[0049] For high-impurity green ammonia feedstock (O2 4.5ppm, Fe³⁺ 0.4ppb, H2 1.5%), when the O2 concentration exceeds 1ppm, the catalytic hydrogenation unit strictly adopts a Pd-Pt / TiO2 bimetallic catalyst (Pd 0.5wt%, Pt 0.3wt%), and reacts for 90 minutes at a precise temperature of 170℃ and 2.0MPa to completely convert oxygen into water molecules.

[0050] The system then enters a three-stage adsorption system. The first stage, 3A molecular sieve, operates at a constant temperature of -15℃, with moisture content precisely controlled at 10 ppb. The second stage, nickel-based catalyst, operates at a constant temperature of 10℃, with O2 residue precisely reduced to 0.5 ppb. The third stage, composite adsorbent (silica gel and activated carbon in a mass ratio of 3:1), operates at a constant temperature of 20℃, with heavy metal ion concentration stabilized at 0.1 ppb.

[0051] The operating pressure of the distillation unit is strictly maintained at 0.8 MPa, the top temperature is precisely controlled at -50℃ to achieve efficient recovery of light components, and the bottom temperature is precisely controlled at 35℃ to prevent the decomposition of heat-sensitive impurities through falling film evaporation.

[0052] The terminal processing unit sequentially passes the ion exchange with chelating resin (metal ion concentration 0.009ppt), filtration through a 0.05μm pore size PTFE membrane (particulate matter concentration 0.7 particles / mL), and precise dilution with ultrapure water to a concentration of 29.6%.

[0053] Simulation results show that the product has 0.009 ppt of metal ions, 0.7 particles / mL of particulate matter, an ammonia recovery rate of 99.999%, and an energy consumption of 2.5 kWh / kg. All indicators are significantly better than the SEMI C8 standard (metal <5 ppt, particles <5 particles / mL).

[0054] This embodiment, by precisely defining the parameter thresholds (temperature 170℃, time 90 minutes) and adsorbent switching cycle (12 hours) when O2 > 1ppm, forms a clear technical difference from the traditional process (energy consumption 4.2kWh / kg, metal ions 3.2ppt), proving that the present invention can still achieve stable production of 7N purity under high impurity raw materials, and verifying the reproducibility of the dynamic response mechanism.

[0055] For low-impurity green ammonia feedstock (O2 0.3ppm, Fe³⁺ 0.05ppb, H2 0.1%), the catalytic hydrogenation unit strictly adopts a Pd-Pt / TiO2 bimetallic catalyst (Pd content 0.5wt%, Pt content 0.3wt%), and reacts for 120 minutes at a precise temperature of 150℃ and 2.0MPa to completely convert oxygen into water molecules.

[0056] The system then enters a three-stage adsorption system. The first stage, 3A molecular sieve, operates at a constant temperature of -15℃, with moisture content precisely controlled at 10 ppb. The second stage, nickel-based catalyst, operates at a constant temperature of 10℃, with O2 residue precisely reduced to 0.5 ppb. The third stage, composite adsorbent (silica gel and activated carbon in a mass ratio of 3:1), operates at a constant temperature of 20℃, with heavy metal ion concentration stabilized at 0.1 ppb.

[0057] The operating pressure of the distillation unit is strictly maintained at 0.8 MPa, the top temperature is precisely controlled at -50℃ to achieve efficient recovery of light components, and the bottom temperature is precisely controlled at 35℃ to prevent the decomposition of heat-sensitive impurities through falling film evaporation.

[0058] The terminal processing unit sequentially passes the ion exchange with chelating resin (metal ion concentration 0.007ppt), filtration through a 0.05μm pore size PTFE membrane (particulate matter concentration 0.6 particles / mL), and ultrapure water for precise dilution to a concentration of 29.6%.

[0059] Simulation results show that the product has 0.007 ppt of metal ions, 0.6 particles / mL of particulate matter, an ammonia recovery rate of 99.999%, and an energy consumption of 2.3 kWh / kg. All indicators are significantly better than the SEMI C8 standard (metal <5 ppt, particles <5 particles / mL).

[0060] This embodiment, by precisely defining the basic process parameters (temperature 150℃, time 120 minutes, adsorption cycle 24 hours) under low impurity conditions (O2 < 1ppm), forms a clear technical difference from the traditional process (energy consumption 4.2kWh / kg, metal ions 3.2ppt), proving that the present invention can still achieve stable production of 7N purity under low impurity raw materials, and verifying the ability of the gradient purification system to fully cover the impurity spectrum of green ammonia raw materials.

[0061] A typical green ammonia feedstock (O2 1.2ppm, Fe³⁺ 0.2ppb, H2 0.5%) was processed using a traditional process. The process parameters were strictly limited to a distillation column operating pressure of 0.6MPa, a column top temperature of -40℃, and a column bottom temperature of 45℃. After three stages of distillation, a single-stage adsorption was performed.

[0062] Simulation results show that the product has a metal ion concentration of 3.2 ppt, a particulate matter concentration of 3.5 particles / mL, an ammonia recovery rate of 95%, an energy consumption of 4.2 kWh / kg, and a purity of only 6N (99.9999%), which cannot meet the semiconductor-grade requirements of 7N (99.99999%).

[0063] The comparative data between this comparative example and Example 1 of the present invention clearly show that the metal ion concentration is 399 times higher (0.008ppt vs 3.2ppt), energy consumption increases by 76.2% (2.4kWh / kg vs 4.2kWh / kg), and ammonia recovery rate is 4.999% lower. The root cause of the failure of Comparative Example 1 is that it did not consider the unique impurity profile of green ammonia feedstock (O2 1.2ppm needs to be specifically removed). Traditional multi-stage distillation can only handle industrial ammonia impurities and cannot effectively remove the unique oxygen impurities and metal residues of green ammonia, leading to impurity accumulation. The parameters are set to a single fixed value (pressure 0.6MPa, temperature -40℃ / 45℃), but its technical solution is fundamentally different from the "catalytic hydrogenation pre-treatment - three-stage adsorption - single-stage distillation" gradient system of the present invention: the present invention directly converts O2 into H2O through catalytic hydrogenation, avoiding the inefficient process of adding an additional distillation step in the traditional process, and achieving precise removal of impurities.

[0064] Based on the existing publicly available process routes, only multi-stage distillation is used to deoxygenate typical green ammonia feedstock (O2 1.2ppm, Fe³⁺ 0.2ppb, H2 0.5%). The process parameters are strictly limited to the distillation column operating pressure of 0.7MPa, column top temperature of -45℃, column bottom temperature of 40℃, and 4-stage distillation.

[0065] Simulation results show that the product has a metal ion concentration of 4.8 ppt, a particulate matter concentration of 4.2 particles / mL, an ammonia recovery rate of 95.5%, and an energy consumption of 4.0 kWh / kg. The purity only reaches 6N (99.9999%), failing to meet the 7N (99.99999%) semiconductor-grade requirements. Compared to Example 1 of this invention, the metal ion concentration is 599 times higher (0.008 ppt vs 4.8 ppt), energy consumption increases by 66.7% (2.4 kWh / kg vs 4.0 kWh / kg), and the ammonia recovery rate is 4.499% lower.

[0066] The failure of Comparative Example 2 stemmed from its failure to design a process specifically for the unique impurity profile of green ammonia (O2 1.2 ppm, residual Pd / Pt metal catalyst) generated by the "green electricity-water electrolysis-ammonia synthesis" pathway. Instead, it merely applied industrial ammonia purification methods, resulting in inefficient conversion of oxygen impurities and severe accumulation of metal residues. While the parameters were set to a single fixed value (pressure 0.7 MPa, temperature -45℃ / 40℃), the technical solution fundamentally differed from the "catalytic hydrogenation pre-treatment-three-stage adsorption-single-stage distillation" gradient system of this invention. This invention directly converts O2 to H2O at 150℃ using a Pd-Pt / TiO2 catalyst, avoiding redundant steps in multi-stage distillation and achieving precise impurity removal. In contrast, existing multi-stage distillation methods can only handle conventional impurities and cannot respond to the unique impurity combination of green ammonia.

[0067] The detailed data comparison between the above embodiments and comparative examples is shown in the table below: Table 1: Comparison of Data from Examples Table 2: Comparison of comparative data .

Claims

1. A gradient purification method for electronic-grade ultra-high purity ammonia water, characterized in that, Includes the following steps: S1. Obtain green ammonia raw material, and use an online mass spectrometer and gas chromatography-coupled device to detect the impurity spectrum in the green ammonia raw material in real time. The impurity spectrum includes at least the concentrations of oxygen, hydrogen, metal ions and water. S2. Based on the detected impurity spectrum, dynamically adjust the purification process parameters; S3. The green ammonia raw material is sequentially passed through a catalytic hydrogenation unit, a three-stage adsorption unit, a single-stage distillation unit and a terminal polishing unit for gradient purification to obtain electronic-grade ultra-high purity ammonia water with a metal ion content ≤0.009ppt, a particulate matter concentration ≤0.8 particles / mL and a purity of 7N+. S4. When the detected oxygen concentration is higher than 1 ppm, the reaction temperature of the catalytic hydrogenation unit is increased to 170°C and the adsorbent switching cycle is shortened to 12 hours; when the oxygen concentration is lower than 1 ppm, the reaction temperature of the catalytic hydrogenation unit is maintained at 150°C and the adsorbent switching cycle is maintained at 24 hours.

2. The gradient purification method according to claim 1, characterized in that, The catalytic hydrogenation unit uses a Pd-Pt / TiO2 bimetallic catalyst and reacts for 90-120 minutes at a pressure of 2.0 MPa to completely convert oxygen into water; the Pd-Pt / TiO2 bimetallic catalyst has a Pd loading of 0.5 wt% and a Pt loading of 0.3 wt%.

3. The gradient purification method according to claim 1, characterized in that, The three-stage adsorption unit includes: First-stage adsorption: Using 3A molecular sieve, operating at a constant temperature of -15℃, the moisture content is controlled to 10ppb; Second-stage adsorption: Using a nickel-based catalyst, the oxygen residue was reduced to 0.5 ppb by operating at a constant temperature of 10℃. Third-stage adsorption: A composite adsorbent with a silica gel to activated carbon mass ratio of 3:1 was used and operated at a constant temperature of 20℃ to stabilize the heavy metal ion concentration at 0.1 ppb.

4. The gradient purification method according to claim 1, characterized in that, The single-stage distillation unit uses a structured packed column, with the operating pressure strictly maintained at 0.8 MPa, the top temperature precisely controlled at -50℃, and the bottom temperature precisely controlled at 35℃.

5. The gradient purification method according to claim 1, characterized in that, The terminal polishing unit includes, in sequence, a chelating resin ion exchanger and a PTFE membrane filter with a pore size of 0.05 μm.

6. The gradient purification method according to claim 1, characterized in that, It also includes recovering 100% of the cooling capacity of the -50°C top condenser of the distillation column and using it for precooling the adsorption unit, as well as replacing electric heating with a heat pump system.

7. An electronic-grade ultra-high purity ammonia gradient purification system for implementing the method according to any one of claims 1-6, characterized in that, include: The impurity detection unit, consisting of an online mass spectrometer and a gas chromatograph, is used to detect the impurity spectrum in green ammonia raw materials in real time. The control unit is connected to the impurity detection unit and is used to dynamically adjust the operating parameters of subsequent units according to the impurity spectrum. The catalytic hydrogenation unit, connected to the control unit, is filled with a Pd-Pt / TiO2 bimetallic catalyst to convert oxygen in the green ammonia feedstock into water. The three-stage adsorption unit, connected to the outlet of the catalytic hydrogenation unit, includes a first-stage 3A molecular sieve adsorber, a second-stage nickel-based catalyst adsorber, and a third-stage silica gel-activated carbon composite adsorber connected in series, for removing moisture, residual oxygen, and heavy metal ions. The single-stage distillation unit is connected to the outlet of the three-stage adsorption unit and is a structured packed distillation column with an operating pressure of 0.8 MPa, a top temperature of -50°C, and a bottom temperature of 35°C. The terminal polishing unit, connected to the outlet of the single-stage distillation unit, includes a chelating resin ion exchanger and a PTFE membrane filter with a pore size of 0.05 μm connected in series.

8. The gradient purification system according to claim 7, characterized in that, The catalytic hydrogenation unit is also equipped with a temperature regulation device and an adsorbent switching device. When the impurity detection unit detects an oxygen concentration >1 ppm, the control unit instructs the temperature regulation device to raise the reaction temperature to 170°C and shorten the adsorbent switching cycle to 12 hours. When the oxygen concentration <1 ppm, the control unit instructs the temperature regulation device to maintain the reaction temperature at 150°C and maintain the adsorbent switching cycle at 24 hours.

9. The gradient purification system according to claim 7, characterized in that, The overhead condenser of the single-stage distillation unit is connected to the precooling device of the three-stage adsorption unit through a cold energy recovery pipeline, which is used to recover and reuse 100% of the -50℃ cold energy; the bottom of the single-stage distillation unit is heated by a heat pump system.

10. The gradient purification system according to claim 7, characterized in that, The impurity spectrum detected by the impurity detection unit includes at least oxygen (0.1-5 ppm), hydrogen (0.05-2%), iron ions (0.01-0.5 ppb), and moisture.

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