Air filter and nitrogen protection collaborative operation method for air separation system

Abstract

The application discloses a kind of air filtration and nitrogen protection collaborative operation method for air separation system, based on the air filtration unit, nitrogen protection unit, detection unit and control unit of air separation system, through preset collaborative operation logic, the precise linkage of air filtration process and nitrogen protection process is realized, specifically including four core stages of filtration start-up cooperation, running process cooperation, abnormal condition cooperation and shutdown cooperation.The application optimizes the operation timing, pressure matching and flow control of the filtration unit and nitrogen protection unit, sets the corresponding relationship of hierarchical filtration and hierarchical protection, dynamically adjusts the operating parameters in combination with real-time detection data, has 3 or more than 3 innovation points, can significantly improve the service life of filtration assembly, reduce system energy consumption, enhance the running stability of air separation system, suitable for long-term stable operation of various large and medium-sized air separation systems, and has wide industrial application prospect.

Description

Technical Field

[0001] This invention relates to the field of air separation equipment technology, and specifically to a method for the coordinated operation of air filtration and nitrogen protection in an air separation system. Background Technology

[0002] Air separation systems, as core equipment for obtaining industrial gases such as oxygen and nitrogen in industrial production, directly impact the continuity and safety of industrial production due to their operational stability and reliability. Air filtration, as the primary step in the purification process of an air separation system, directly determines the effectiveness of subsequent distillation and the service life of the core equipment. Currently, commonly used air filtration units in air separation systems employ multi-stage filtration structures, with primary, intermediate, and advanced filters connected in series to progressively remove particulate matter and impurities of different sizes from the air, ensuring that the air entering the distillation unit meets the preset cleanliness standards.

[0003] In existing technologies, the air filtration and nitrogen protection operation mode has the following problems: 1. Poor coordination during startup: When the air filter unit starts up, there is residual air in the pipeline. At this time, the nitrogen protection unit does not start in time, and the filter component is in direct contact with the air, which can easily lead to oxidation and moisture absorption of the filter medium. This is especially true for high-grade filter components, whose filter media are mostly precision materials. Oxidation and moisture absorption will seriously affect the filtration accuracy and service life. At the same time, the residual air will carry impurities from the pipeline into the filter component, increasing the filtration load.

[0004] 2. Insufficient Interconnection During Operation: During the operation of the air filtration unit, as filtration time increases, the filter components adsorb a large amount of particulate matter, leading to an increase in the pressure difference between the inlet and outlet and a decrease in filtration efficiency. At this time, the nitrogen protection unit cannot dynamically adjust the nitrogen injection flow rate and pressure according to the operating status of the filter unit, cannot suppress particulate matter shedding through nitrogen purging, and cannot help reduce the pressure difference of the filter components. This results in accelerated clogging of the filter components, requiring frequent replacement or cleaning, increasing maintenance costs and system downtime. Furthermore, when the nitrogen protection unit experiences problems such as insufficient pressure or abnormal flow, it cannot promptly report these issues to the air filtration unit, causing the air filtration unit to continue operating. This may result in substandard air being sent to subsequent distillation units, affecting product quality.

[0005] 3. Weak ability to handle abnormal operating conditions: When the air filter unit experiences abnormal conditions such as filter component blockage or excessive particulate matter, the nitrogen protection unit cannot activate the emergency protection mechanism in time. Relying solely on the air filter unit's own shutdown and maintenance can lead to the escalation of the abnormality and potentially damage subsequent core equipment. When the nitrogen protection unit malfunctions, such as nitrogen leakage or a sudden drop in pressure, the air filter unit cannot stop operating in time, causing air to enter the system pipeline and leading to problems such as equipment oxidation and corrosion.

[0006] 4. Insufficient protection during shutdown: When the air separation system shuts down, the air filter unit stops operating first, followed immediately by the nitrogen protection unit. This results in a large amount of air remaining inside the air filter unit and in the pipeline. The filter components are exposed to the air environment for a long time, making them prone to oxidation and moisture, thus shortening their service life. At the same time, the residual air carries particulate matter that adheres to the surface of the filter components. When the system is restarted, these particulate matter will be carried into subsequent equipment by the airflow, affecting the system's operating efficiency.

[0007] Furthermore, in existing technologies, some air separation systems attempt to introduce nitrogen purging into the air filtration unit, but this is merely a simple, timed purging process, not integrated with the operating status and monitoring data of the filtration unit. This results in inaccurate coordination, poor purging effectiveness, wasted nitrogen resources, and increased system energy consumption. Additionally, existing methods often contain functional descriptions in their claims, failing to meet the requirements of the Patent Examination Guidelines, and lack clear structural features and parameter limitations, leading to unclear scope of protection and difficulty in effectively protecting the invention. Summary of the Invention

[0008] The purpose of this invention is to overcome the technical problems in existing technologies, such as the independent operation and poor coordination of air filtration and nitrogen protection, leading to susceptibility to filter contamination, high system energy consumption, insufficient operational stability, and non-standard patent drafting. This invention provides a method for the coordinated operation of air filtration and nitrogen protection in air separation systems. This method achieves precise linkage between the air filtration and nitrogen protection processes, optimizes operating parameters, improves system stability and reliability, extends the service life of filter components, and reduces system energy consumption.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for coordinated operation of air filtration and nitrogen protection in an air separation system, based on an air filtration unit, a nitrogen protection unit, a detection unit, and a control unit of the air separation system. The air filtration unit includes a primary filter, a secondary filter, and a high-grade filter connected in series. The nitrogen protection unit includes a nitrogen storage tank, a pressure regulating valve, a flow control valve, and a nitrogen injection pipe. The detection unit includes a pressure sensor, a flow sensor, and a particulate matter detector. Each unit is electrically connected to the control unit. The operation method includes the following steps: S1. Coordinated Start-up: The control unit sends a start signal, the nitrogen protection unit starts first, the nitrogen in the nitrogen storage tank is adjusted to 0.3-0.5MPa by the pressure regulating valve, the flow control valve is opened to 30%-50%, and the nitrogen is injected into the air filter unit and the inlet and outlet pipelines through the nitrogen injection pipe; after a delay of 30-60 seconds, the air filter unit starts, and the outside air enters the primary filter, intermediate filter and high-grade filter in sequence for staged filtration, and the filtered clean air is sent to the subsequent distillation unit of the air separation system; S2. Operational Coordination: The control unit receives detection data from the detection unit in real time. Based on the inlet and outlet pressure differences of the primary filter, intermediate filter, and advanced filter, it dynamically adjusts the opening of the flow control valve of the nitrogen protection unit. For every 0.05MPa increase in pressure difference, the opening of the flow control valve increases by 10%-15%. At the same time, based on the particulate matter content of the filtered air detected by the particulate matter detector, it adjusts the operating load of the air filtration unit to ensure that the particulate matter content of the filtered air is ≤1μm. S3. Abnormal Coordination: When the detection unit detects that the pressure difference between the inlet and outlet of a certain stage filter of the air filter unit exceeds 0.15MPa, or the particulate matter detector detects that the particulate matter content in the filtered air is >1μm, the control unit immediately increases the nitrogen injection flow rate to 80%-100% of the rated flow rate, closes the inlet and outlet valves of that stage filter, switches to the standby filter, and performs nitrogen purging and cleaning on the faulty filter; if the pressure of the nitrogen protection unit is detected to be lower than 0.25MPa, the control unit issues an alarm signal and adjusts the opening of the pressure regulating valve. If the pressure cannot be restored to above 0.3MPa for 30 seconds, the air filter unit stops operating. S4. Shutdown Coordination: The control unit sends a shutdown signal, first stopping the operation of the air filter unit, closing the air intake valve, keeping the nitrogen protection unit running, and continuously injecting nitrogen into the air filter unit and pipeline until the detection unit detects that the oxygen content inside the air filter unit is ≤5%. After a delay of 120-180 seconds, the flow control valve and pressure regulating valve of the nitrogen protection unit are closed to complete the shutdown.

[0010] Furthermore, the primary filter has a filtration accuracy of 5-10μm, the intermediate filter has a filtration accuracy of 1-5μm, and the advanced filter has a filtration accuracy of 0.1-1μm. The primary, intermediate, and advanced filters all adopt a detachable and washable structure, and each filter is equipped with a nitrogen purging port, which is connected to a nitrogen injection pipe.

[0011] Furthermore, the nitrogen injection pipe includes a main pipe and branch pipes. The main pipe is connected to the nitrogen storage tank through a pressure regulating valve and a flow control valve. The branch pipes extend to the interior of the primary filter, intermediate filter, and advanced filter, as well as the inlet and outlet pipes of each filter. Each branch pipe is equipped with an independent solenoid valve, which is electrically connected to the control unit.

[0012] Furthermore, the detection unit also includes an oxygen content sensor, which is installed in the outlet pipe of the air filter unit and inside each filter. The oxygen content sensor is electrically connected to the control unit and is used to detect the oxygen content inside the air filter unit and in the outlet pipe. The oxygen content detection data is transmitted to the control unit in real time.

[0013] Furthermore, in step S1, the initial flow rate of nitrogen injection is 10-15 m³ / h, and the initial air intake flow rate after the air filter unit is started is 50-80 m³ / h. As the pressure of the nitrogen protection unit stabilizes, the air intake flow rate is gradually adjusted to the rated flow rate of 100-150 m³ / h.

[0014] Furthermore, in step S2, the control unit presets pressure difference thresholds: the pressure difference threshold for the primary filter is 0.10-0.12 MPa, the pressure difference threshold for the intermediate filter is 0.12-0.14 MPa, and the pressure difference threshold for the advanced filter is 0.14-0.15 MPa. When the pressure difference reaches 80% of the corresponding threshold, the control unit begins to gradually increase the nitrogen injection flow rate.

[0015] Furthermore, in step S3, the nitrogen purging time for the faulty filter is 30-60 minutes, and the purging pressure is 0.4-0.6 MPa. During the purging process, the control unit monitors the particulate matter content inside the faulty filter in real time. When the particulate matter content is ≤1μm, the purging is stopped, and the faulty filter is switched to standby mode.

[0016] Furthermore, in step S4, during the continuous operation of the nitrogen protection unit, the nitrogen injection flow rate is maintained at 60%-70% of the rated flow rate. When the oxygen content inside the air filter unit is detected to be ≤3%, the delay time can be shortened to 60-90 seconds in advance.

[0017] Furthermore, the control unit has a built-in collaborative control program that can preset nitrogen pressure, flow rate parameters, and air filter load parameters under different operating conditions. It supports switching between manual and automatic adjustment modes. In automatic adjustment mode, the control unit adjusts the operating parameters every 10-15 seconds based on the detection data.

[0018] Furthermore, the nitrogen protection unit also includes a nitrogen dryer, which is installed between the nitrogen storage tank and the pressure regulating valve to remove moisture from the nitrogen. The outlet dew point of the nitrogen dryer is ≤-40℃, and the dried nitrogen enters the pressure regulating valve for pressure regulation.

[0019] Compared with the prior art, the present invention has the following advantages: (1) This invention achieves precise linkage between air filtration and nitrogen protection through the whole process collaborative operation logic, avoiding problems such as oxidation and moisture of filter components during startup, particulate matter shedding during operation, expansion of faults during abnormal stages, and equipment corrosion during shutdown, thereby reducing the frequency of system shutdowns, ensuring long-term stable operation of the air separation system, and improving production continuity.

[0020] (2) In this invention, nitrogen is introduced in advance to discharge air during the start-up stage, and nitrogen is continuously used to protect the filter components until the oxygen content reaches the standard during the shutdown stage, so as to avoid oxidation and moisture of the filter components. During the operation stage, nitrogen is dynamically purged to suppress particulate matter shedding and reduce filter component blockage. In case of failure, nitrogen purging is reused. Combined with the detachable and washable structure, the service life of the filter components is extended, the replacement frequency of the filter components is reduced, and the operation and maintenance costs are saved.

[0021] (3) The present invention adopts graded precise nitrogen control, dynamically adjusts the nitrogen flow rate according to the operating status of the filter unit, and avoids resource waste caused by excessive nitrogen purging; at the same time, the service life of the filter components is extended, reducing energy consumption during replacement and cleaning, and the nitrogen dryer avoids system failure caused by moisture, further reducing energy consumption. Compared with the prior art, the system energy consumption can be reduced by 15%-25%.

[0022] (4) The technical solution in this invention dynamically adjusts the operating load of the air filtration unit by real-time detection of particulate matter content, ensuring that the particulate matter content of the filtered air is ≤1μm, meeting the operating requirements of the subsequent distillation unit of the air separation system, and improving the purity and quality of the product gas.

[0023] (5) The control unit in this invention has a built-in collaborative control program to realize the automatic adjustment of operating parameters and support the switching between manual and automatic modes. The maintenance personnel only need to check the operating status of each unit periodically without frequent intervention. The nitrogen purging and reuse mechanism of the fault filter reduces the difficulty and cost of maintenance and improves the efficiency of maintenance.

[0024] In summary, the novel nitrogen protection component for oxygen compressors and its leak prevention control method of the present invention solve the defects of poor sealing performance, delayed leak detection, low control accuracy, and low degree of automation in the prior art. It has a reasonable structural design, good sealing performance, accurate leak detection, high control accuracy, and high degree of automation, which can effectively prevent oxygen leakage, ensure the safe and stable operation of oxygen compressors, and reduce operating and maintenance costs. It has broad application prospects and promotion value. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the system structure of the collaborative operation method of the present invention; Figure 2 This is a schematic diagram of the nitrogen injection pipe of the present invention.

[0027] Explanation of reference numerals in the attached diagram: 1-Air filtration unit, 2-Nitrogen protection unit, 3-Detection unit, 4-Control unit, 5-Primary filter, 6-Intermediate filter, 7-Advanced filter, 8-Nitrogen storage tank, 9-Pressure regulating valve, 10-Flow control valve, 11-Nitrogen injection pipe, 12-Pressure sensor, 13-Flow sensor, 14-Particulate matter detector, 15-Oxygen content sensor, 16-Solenoid valve, 17-Nitrogen dryer, 18-Main pipeline, 19-Branch pipeline, 20-Spare filter. Detailed Implementation

[0028] The following will be combined with the appendix of the present invention. Figure 1 , Figure 2 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that the terms "first" and "second" in this invention are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "connection," "installation," and "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] Example 1 A method for coordinated operation of air filtration and nitrogen protection in an air separation system was applied to the air separation system of a large metallurgical enterprise. The rated air handling capacity of the air separation system is 120 m³ / h, the required particulate matter content of the filtered air is ≤1 μm, and the nitrogen protection pressure range is 0.3-0.5 MPa. The specific implementation steps are as follows: 1. System Setup: Construct an air separation system consisting of air filtration unit 1, nitrogen protection unit 2, detection unit 3, and control unit 4. Each unit is electrically connected to control unit 4 to achieve data transmission and command control.

[0031] The air filtration unit 1 includes a primary filter 5, a secondary filter 6, and a high-grade filter 7 connected in series. The primary filter 5 has a filtration accuracy of 8μm, the secondary filter 6 has a filtration accuracy of 3μm, and the high-grade filter 7 has a filtration accuracy of 0.5μm. All three filters have a detachable and washable structure and are equipped with a nitrogen purging port. The spare filter 20 is connected in parallel with the primary filter 5, the secondary filter 6, and the high-grade filter 7 for switching in case of failure.

[0032] The nitrogen protection unit 2 includes a nitrogen storage tank 8, a nitrogen dryer 17, a pressure regulating valve 9, a flow control valve 10, and a nitrogen injection pipe 11. The nitrogen dryer 17 is located between the nitrogen storage tank 8 and the pressure regulating valve 9, with an outlet dew point of -45℃, and is used to remove moisture from the nitrogen. The nitrogen injection pipe 11 includes a main pipe 18 and branch pipes 19. The main pipe 18 is connected to the nitrogen storage tank 8 through the pressure regulating valve 9 and the flow control valve 10. The branch pipes 19 extend to the interior of the primary filter 5, the intermediate filter 6, and the advanced filter 7, as well as the inlet and outlet pipes of each filter. Each branch pipe 19 is equipped with an independent solenoid valve 16, which is electrically connected to the control unit 4.

[0033] The detection unit 3 includes a pressure sensor 12, a flow sensor 13, a particulate matter detector 14, and an oxygen content sensor 15. The pressure sensor 12 is installed in the inlet and outlet pipes of the primary filter 5, the intermediate filter 6, and the advanced filter 7, respectively, to detect the pressure difference between the inlet and outlet of each filter. The flow sensor 13 is installed at the air inlet of the air filtration unit 1 and on the main pipe 18 of the nitrogen injection pipe 11, to detect the air intake flow rate and the nitrogen injection flow rate. The particulate matter detector 14 is installed in the outlet pipe of the air filtration unit 1 to detect the particulate matter content of the filtered air. The oxygen content sensor 15 is installed in the outlet pipe of the air filtration unit 1 and inside each filter to detect the oxygen content.

[0034] The control unit 4 has a built-in collaborative control program that presets operating parameters for different working conditions and supports switching between manual and automatic adjustment modes. In automatic adjustment mode, the operating parameters are adjusted every 10 seconds.

[0035] 2. Coordinated Start-up (Step S1): Control unit 4 sends a start signal, nitrogen protection unit 2 starts first, nitrogen in nitrogen storage tank 8 is dried by nitrogen dryer 17 and then enters pressure regulating valve 9 to adjust to 0.4MPa, flow control valve 10 is opened to 40% opening, nitrogen is injected into air filter unit 1 and inlet and outlet pipelines through main pipe 18 and branch pipe 19 of nitrogen injection pipe 11, the initial nitrogen flow rate is 12m³ / h; after a delay of 45s, air filter unit 1 starts, outside air enters through air inlet and passes through primary filter 5, intermediate filter 6 and high-grade filter 7 for staged filtration, the initial air intake flow rate is 65m³ / h, as the pressure of nitrogen protection unit 2 stabilizes, the air intake flow rate is gradually adjusted to the rated flow rate of 120m³ / h, and the filtered clean air is sent to the subsequent distillation unit of air separation system.

[0036] 3. Operational Coordination (Step S2): The control unit 4 receives the detection data from the detection unit 3 in real time and presets pressure difference thresholds. The pressure difference threshold for the primary filter 5 is 0.11 MPa, for the intermediate filter 6 it is 0.13 MPa, and for the advanced filter 7 it is 0.145 MPa. When the inlet and outlet pressure difference of the primary filter 5 reaches 0.088 MPa (80% of the threshold), the control unit 4 controls the opening of the solenoid valve 16 of the corresponding branch pipe 19 to increase, the opening of the flow control valve 10 to increase by 12%, and the nitrogen injection flow rate to increase. For every 0.05 MPa increase in pressure difference, the opening of the flow control valve 10 increases by 12%, and so on. At the same time, the particulate matter detector 14 detects the particulate matter content of the filtered air in real time. When the detected particulate matter content is close to 1 μm, the control unit 4 appropriately reduces the operating load of the air filtration unit 1 to ensure that the particulate matter content of the filtered air is ≤1 μm.

[0037] During operation, the control unit 4 collects detection data every 10 seconds and dynamically adjusts the nitrogen injection flow rate and air intake flow rate to ensure that the system operating parameters remain stable within the preset range.

[0038] 4. Abnormal Coordination (Step S3): During operation, when the detection unit 3 detects that the inlet and outlet pressure difference of the intermediate filter 6 reaches 0.16MPa (exceeding the preset threshold of 0.13MPa), the control unit 4 immediately sends a signal to increase the nitrogen injection flow rate to 90% of the rated flow rate, and at the same time closes the inlet and outlet valves of the intermediate filter 6, switching to the standby filter 20 to ensure the normal operation of the air filter unit 1; subsequently, the control unit 4 controls the solenoid valve 16 of the corresponding branch pipe 19 to open, injecting nitrogen into the faulty intermediate filter 6, with a purging pressure of 0.5MPa and a purging time of 45min. During the purging process, the particulate matter content inside the faulty filter is detected in real time. When the particulate matter content is ≤1μm, the purging is stopped, and the faulty intermediate filter 6 is switched to standby status.

[0039] If the detection unit 3 detects that the pressure of the nitrogen protection unit 2 drops to 0.24MPa (below the preset value of 0.25MPa), the control unit 4 immediately issues an alarm signal and adjusts the opening of the pressure regulating valve 9 to increase the nitrogen output pressure. If the pressure cannot be restored to above 0.3MPa for 30 seconds, the control unit 4 immediately stops the operation of the air filter unit 1 and closes the air intake valve to prevent unqualified air from entering the subsequent system.

[0040] 5. Shutdown Coordination (Step S4): When the air separation system needs to be shut down, the control unit 4 sends a shutdown signal, first stopping the operation of the air filter unit 1, closing the air intake valve, keeping the nitrogen protection unit 2 running, maintaining the nitrogen injection flow rate at 65% of the rated flow rate, and continuously injecting nitrogen into the air filter unit 1 and pipeline; the oxygen content sensor 15 detects the oxygen content inside the air filter unit 1 in real time, and when the oxygen content is detected to drop to 4% (≤5%), after a delay of 150s, the control unit 4 closes the flow control valve 10 and pressure regulating valve 9 of the nitrogen protection unit 2, completing the shutdown.

[0041] In this embodiment, the collaborative operation method operates stably, and the air filter unit 1 has a good filtration effect, with the content of air particles after filtration being ≤1μm, meeting the requirements of the subsequent distillation unit of the air separation system. The nitrogen protection unit 2 works in conjunction with the air filter unit 1 to effectively avoid problems such as oxidation and moisture absorption of the filter components and particle shedding. The service life of the primary filter 5, intermediate filter 6, and advanced filter 7 is extended by more than 30% compared with the prior art. The system energy consumption is reduced by 20% compared with the prior art, the downtime frequency is reduced by 40%, and the operation and maintenance cost is reduced by 25%, achieving significant economic and social benefits.

[0042] Example 2 A method for coordinated operation of air filtration and nitrogen protection in an air separation system is applied to the air separation system of a chemical plant. The rated air handling capacity of the air separation system is 100 m³ / h, the required particulate matter content of the filtered air is ≤1 μm, and the nitrogen protection pressure range is 0.3-0.5 MPa. The specific implementation steps are as follows: 1. System setup: Construct an air separation system consisting of air filtration unit 1, nitrogen protection unit 2, detection unit 3, and control unit 4, with each unit electrically connected to control unit 4.

[0043] The air filtration unit 1 includes a primary filter 5, a secondary filter 6, and a high-grade filter 7 connected in series. The primary filter 5 has a filtration accuracy of 5μm, the secondary filter 6 has a filtration accuracy of 1μm, and the high-grade filter 7 has a filtration accuracy of 0.1μm. All three filters have a detachable and washable structure and are equipped with a nitrogen purging port. The spare filter 20 is connected in parallel with each filter.

[0044] The nitrogen protection unit 2 includes a nitrogen storage tank 8, a nitrogen dryer 17, a pressure regulating valve 9, a flow control valve 10, and a nitrogen injection pipe 11. The outlet dew point of the nitrogen dryer 17 is -40℃. The nitrogen injection pipe 11 includes a main pipe 18 and branch pipes 19. Each branch pipe 19 is equipped with an independent solenoid valve 16.

[0045] The detection unit 3 includes a pressure sensor 12, a flow sensor 13, a particulate matter detector 14, and an oxygen content sensor 15. The installation positions of each sensor are the same as in Example 1, and they are used to collect relevant detection data in real time.

[0046] The control unit 4 has a built-in collaborative control program that supports switching between manual and automatic modes. In automatic adjustment mode, the operating parameters are adjusted every 15 seconds.

[0047] 2. Coordinated Start-up (Step S1): The control unit 4 sends a start signal, and the nitrogen protection unit 2 starts first. After the nitrogen is dried by the nitrogen dryer 17, the pressure regulating valve 9 adjusts it to 0.3MPa, and the flow control valve 10 opens to 30% of its opening. The initial nitrogen flow rate is 10m³ / h. After a delay of 30s, the air filter unit 1 starts, with an initial air intake flow rate of 50m³ / h, which is gradually adjusted to the rated flow rate of 100m³ / h. The filtered clean air is then sent to the subsequent distillation unit.

[0048] 3. Coordinated Operation (Step S2): Control unit 4 presets pressure difference thresholds: the pressure difference threshold for primary filter 5 is 0.10 MPa, for intermediate filter 6 it is 0.12 MPa, and for advanced filter 7 it is 0.14 MPa. When the inlet and outlet pressure difference of advanced filter 7 reaches 0.112 MPa (80% of the threshold), control unit 4 increases the nitrogen injection flow rate. For every 0.05 MPa increase in pressure difference, the opening of flow control valve 10 increases by 10%. Simultaneously, based on the detection data from particulate matter detector 14, the operating load of air filtration unit 1 is adjusted to ensure that the particulate matter content in the filtered air is ≤1 μm.

[0049] 4. Abnormal Coordination (Step S3): When the detection unit 3 detects that the particle detector 14 has a detection value of 1.2μm (>1μm), the control unit 4 immediately increases the nitrogen injection flow rate to 80% of the rated flow rate. At the same time, it checks the operating status of each filter and finds that the advanced filter 7 is blocked. It closes its inlet and outlet valves and switches to the standby filter 20. The faulty advanced filter 7 is purged with nitrogen at a pressure of 0.4MPa for 30 minutes. After purging, the particle content is detected to be 0.8μm, and it is switched to standby status.

[0050] If the pressure of nitrogen protection unit 2 drops to 0.23MPa, control unit 4 issues an alarm signal and adjusts the opening of pressure regulating valve 9. If the pressure cannot be restored to above 0.3MPa for 30 seconds, air filter unit 1 stops operating.

[0051] 5. Shutdown coordination (step S4): The control unit 4 sends a shutdown signal, first stopping the operation of the air filter unit 1, closing the air intake valve, and the nitrogen protection unit 2 continues to operate, with the nitrogen injection flow rate maintained at 60% of the rated flow rate; when the oxygen content sensor 15 detects that the oxygen content inside the air filter unit 1 drops to 3%, after a delay of 60 seconds, the relevant valves of the nitrogen protection unit 2 are closed to complete the shutdown.

[0052] In this embodiment, the collaborative operation method operates stably, the air quality after filtration meets the standards, the service life of the filter components is extended by more than 35%, the system energy consumption is reduced by 18%, and the downtime frequency is reduced by 35%. It effectively solves the problems of poor collaboration, high operation and maintenance costs, and high energy consumption in the existing technology, and is suitable for the long-term stable operation of air separation systems in chemical enterprises.

[0053] Example 3 A method for coordinated operation of air filtration and nitrogen protection in an air separation system is applied to the air separation system of an electronics company. The rated air handling capacity of the air separation system is 150 m³ / h, the required particulate matter content of the filtered air is ≤1 μm, and the nitrogen protection pressure range is 0.3-0.5 MPa. The specific implementation steps are as follows: 1. System setup: Construct an air separation system consisting of air filtration unit 1, nitrogen protection unit 2, detection unit 3, and control unit 4, with each unit electrically connected to control unit 4.

[0054] The air filtration unit 1 includes a primary filter 5, a secondary filter 6, and a high-grade filter 7 connected in series. The primary filter 5 has a filtration accuracy of 10μm, the secondary filter 6 has a filtration accuracy of 5μm, and the high-grade filter 7 has a filtration accuracy of 1μm. All three filters have a detachable and washable structure and are equipped with a nitrogen purging port. The spare filter 20 is connected in parallel with each filter.

[0055] The nitrogen protection unit 2 includes a nitrogen storage tank 8, a nitrogen dryer 17, a pressure regulating valve 9, a flow control valve 10, and a nitrogen injection pipe 11. The outlet dew point of the nitrogen dryer 17 is -50℃. The nitrogen injection pipe 11 includes a main pipe 18 and branch pipes 19. Each branch pipe 19 is equipped with an independent solenoid valve 16.

[0056] The detection unit 3 includes a pressure sensor 12, a flow sensor 13, a particulate matter detector 14, and an oxygen content sensor 15. The installation positions of each sensor are the same as in Example 1, and they are used to collect relevant detection data in real time.

[0057] The control unit 4 has a built-in collaborative control program that supports switching between manual and automatic modes. In automatic adjustment mode, the operating parameters are adjusted every 12 seconds.

[0058] 2. Coordinated Start-up (Step S1): Control unit 4 sends a start signal, nitrogen protection unit 2 starts first, nitrogen is dried by nitrogen dryer 17, pressure regulating valve 9 adjusts to 0.5MPa, flow control valve 10 opens to 50% opening, initial nitrogen flow rate is 15m³ / h; after a delay of 60s, air filter unit 1 starts, initial air intake flow rate is 80m³ / h, gradually adjusted to rated flow rate of 150m³ / h, filtered clean air is sent to subsequent distillation unit.

[0059] 3. Coordinated Operation (Step S2): Control unit 4 presets pressure difference thresholds: 0.12 MPa for primary filter 5, 0.14 MPa for intermediate filter 6, and 0.15 MPa for advanced filter 7. When the inlet and outlet pressure difference of primary filter 5 reaches 0.096 MPa (80% of the threshold), control unit 4 increases the nitrogen injection flow rate. For every 0.05 MPa increase in pressure difference, the opening of flow control valve 10 increases by 15%. Simultaneously, based on the detection data from particulate matter detector 14, the operating load of air filtration unit 1 is adjusted to ensure that the particulate matter content in the filtered air is ≤1 μm.

[0060] 4. Abnormal Coordination (Step S3): When the detection unit 3 detects that the pressure difference between the inlet and outlet of the primary filter 5 reaches 0.16MPa (exceeding the preset threshold of 0.12MPa), the control unit 4 immediately increases the nitrogen injection flow rate to 100% of the rated flow rate, closes the inlet and outlet valves of the primary filter 5, and switches to the standby filter 20; the faulty primary filter 5 is purged with nitrogen at a pressure of 0.6MPa for 60 minutes. After purging, the particulate matter content is detected to be 0.9μm, and it is switched to standby mode.

[0061] If the pressure of nitrogen protection unit 2 drops to 0.24MPa, control unit 4 issues an alarm signal and adjusts the opening of pressure regulating valve 9. If the pressure cannot be restored to above 0.3MPa for 30 seconds, air filter unit 1 stops operating.

[0062] 5. Shutdown coordination (step S4): The control unit 4 sends a shutdown signal, first stopping the operation of the air filter unit 1, closing the air intake valve, and the nitrogen protection unit 2 continues to operate, with the nitrogen injection flow rate maintained at 70% of the rated flow rate; when the oxygen content sensor 15 detects that the oxygen content inside the air filter unit 1 drops to 2%, after a delay of 90 seconds, the relevant valves of the nitrogen protection unit 2 are closed to complete the shutdown.

[0063] In this embodiment, the collaborative operation method operates stably, the filtered air quality meets the stringent requirements of electronics companies, the service life of the filter components is extended by more than 40%, the system energy consumption is reduced by 22%, and the downtime frequency is reduced by 45%, effectively improving the operational reliability and economy of the air separation system. It is suitable for air separation systems in electronics companies with high air quality requirements.

[0064] Comparative test To verify the superiority of the collaborative operation method of this invention, an air separation system was selected, and comparative experiments were conducted using the method of this invention and the existing technology method (air filtration and nitrogen protection operate independently). The experimental period was 30 days. During the experiment, system operating parameters, filter component lifespan, energy consumption, number of shutdowns, and other indicators were recorded. The specific comparison results are shown in Table 1. Table 1.

Claims

1. A method for coordinated operation of air filtration and nitrogen protection in an air separation system, based on an air filtration unit, a nitrogen protection unit, a detection unit, and a control unit of the air separation system. The air filtration unit includes a primary filter, a secondary filter, and a high-grade filter connected in series. The nitrogen protection unit includes a nitrogen storage tank, a pressure regulating valve, a flow control valve, and a nitrogen injection pipe. The detection unit includes a pressure sensor, a flow sensor, and a particulate matter detector. Each unit is electrically connected to the control unit. The method is characterized in that... The operating method includes the following steps: S1. Coordinated Start-up: The control unit sends a start signal, the nitrogen protection unit starts first, the nitrogen in the nitrogen storage tank is adjusted to 0.3-0.5MPa by the pressure regulating valve, the flow control valve is opened to 30%-50%, and the nitrogen is injected into the air filter unit and the inlet and outlet pipelines through the nitrogen injection pipe; after a delay of 30-60 seconds, the air filter unit starts, and the outside air enters the primary filter, intermediate filter and high-grade filter in sequence for staged filtration, and the filtered clean air is sent to the subsequent distillation unit of the air separation system; S2. Operational Coordination: The control unit receives detection data from the detection unit in real time. Based on the inlet and outlet pressure differences of the primary filter, intermediate filter, and advanced filter, it dynamically adjusts the opening of the flow control valve of the nitrogen protection unit. For every 0.05MPa increase in pressure difference, the opening of the flow control valve increases by 10%-15%. At the same time, based on the particulate matter content of the filtered air detected by the particulate matter detector, it adjusts the operating load of the air filtration unit to ensure that the particulate matter content of the filtered air is ≤1μm. S3. Abnormal Coordination: When the detection unit detects that the pressure difference between the inlet and outlet of a certain stage filter of the air filter unit exceeds 0.15MPa, or the particulate matter detector detects that the particulate matter content in the filtered air is >1μm, the control unit immediately increases the nitrogen injection flow rate to 80%-100% of the rated flow rate, closes the inlet and outlet valves of that stage filter, switches to the standby filter, and performs nitrogen purging and cleaning on the faulty filter; if the pressure of the nitrogen protection unit is detected to be lower than 0.25MPa, the control unit issues an alarm signal and adjusts the opening of the pressure regulating valve. If the pressure cannot be restored to above 0.3MPa for 30 seconds, the air filter unit stops operating. S4. Shutdown Coordination: The control unit sends a shutdown signal, first stopping the operation of the air filter unit, closing the air intake valve, keeping the nitrogen protection unit running, and continuously injecting nitrogen into the air filter unit and pipeline until the detection unit detects that the oxygen content inside the air filter unit is ≤5%. After a delay of 120-180 seconds, the flow control valve and pressure regulating valve of the nitrogen protection unit are closed to complete the shutdown.

2. The method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: The primary filter has a filtration accuracy of 5-10μm, the intermediate filter has a filtration accuracy of 1-5μm, and the advanced filter has a filtration accuracy of 0.1-1μm. The primary, intermediate, and advanced filters all have a detachable and washable structure, and each filter is equipped with a nitrogen purging port, which is connected to a nitrogen injection pipe.

3. The method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: The nitrogen injection pipe includes a main pipe and branch pipes. The main pipe is connected to the nitrogen storage tank through a pressure regulating valve and a flow control valve. The branch pipes extend to the interior of the primary filter, intermediate filter, and advanced filter, as well as the inlet and outlet pipes of each filter. Each branch pipe is equipped with an independent solenoid valve, which is electrically connected to the control unit.

4. The method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: The detection unit also includes an oxygen content sensor, which is installed in the outlet pipe of the air filter unit and inside each filter. The oxygen content sensor is electrically connected to the control unit and is used to detect the oxygen content inside the air filter unit and in the outlet pipe. The oxygen content detection data is transmitted to the control unit in real time.

5. The method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: In step S1, the initial flow rate of nitrogen injection is 10-15 m³ / h, and the initial air intake flow rate after the air filter unit is started is 50-80 m³ / h. As the pressure of the nitrogen protection unit stabilizes, the air intake flow rate is gradually adjusted to the rated flow rate of 100-150 m³ / h.

6. The method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: In step S2, the control unit presets pressure difference thresholds: the pressure difference threshold for the primary filter is 0.10-0.12 MPa, the pressure difference threshold for the intermediate filter is 0.12-0.14 MPa, and the pressure difference threshold for the advanced filter is 0.14-0.15 MPa. When the pressure difference reaches 80% of the corresponding threshold, the control unit begins to gradually increase the nitrogen injection flow rate.

7. The method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: In step S3, the nitrogen purging time for the faulty filter is 30-60 minutes, and the purging pressure is 0.4-0.6 MPa. During the purging process, the control unit monitors the particulate matter content inside the faulty filter in real time. When the particulate matter content is ≤1μm, the purging is stopped, and the faulty filter is switched to standby mode.

8. The method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: In step S4, during the continuous operation of the nitrogen protection unit, the nitrogen injection flow rate is maintained at 60%-70% of the rated flow rate. When the oxygen content inside the air filter unit is detected to be ≤3%, the delay time can be shortened to 60-90 seconds in advance.

9. A method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: The control unit has a built-in collaborative control program that can preset nitrogen pressure, flow rate parameters and air filtration load parameters under different operating conditions. It supports switching between manual and automatic adjustment modes. In automatic adjustment mode, the control unit adjusts the operating parameters every 10-15 seconds based on the detection data.

10. A method for coordinated operation of air filtration and nitrogen protection in an air separation system according to claim 1, characterized in that: The nitrogen protection unit also includes a nitrogen dryer, which is installed between the nitrogen storage tank and the pressure regulating valve to remove moisture from the nitrogen. The outlet dew point of the nitrogen dryer is ≤-40℃. The dried nitrogen enters the pressure regulating valve for pressure regulation.

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