Interactive-circulation output-enhanced nitrogen separation and purification system

Abstract

The invention discloses an interactive circulation and output enhancement nitrogen separation and purification system, and belongs to the technical field of mechanical nitrogen filling. A nitrogen-rich gas cyclopolymerization module comprising a gas storage part is connected in series in a product gas discharge pipeline between a nitrogen-oxygen separation unit and an inerting protection closed space; the inner width of the maximum cross section of the gas storage part is not smaller than the inner diameter of a product gas discharge pipeline in butt joint with the gas storage part, and when nitrogen-rich product gas flows through the nitrogen discharge pipelines and the gas storage part with different cross section areas and then is conveyed to the closed space, Reynolds number change of flowing gas and a turbulence enhancement effect are formed; the gas storage part is connected in series in the nitrogen-rich tail gas backflow pipeline between the closed space and the nitrogen-oxygen separation unit through the other group of gas inlet and outlet holes, and the nitrogen-rich gas cyclic polymerization module plays a role in stabilizing and relaying the cyclic operation of the nitrogen-rich gas and the gas tail gas in the system; in the shutdown period of the nitrogen-oxygen separation unit, the nitrogen-rich gas can be continuously output into the inerting protection closed space, and the concentration compensation effect can be achieved.

Description

An interactive, enhanced-output nitrogen separation and purification system Technical Field

[0001] This invention relates to the field of mechanical nitrogen filling technology, and in particular to an interactive, enhanced nitrogen separation and purification system. Background Technology

[0002] Mechanical nitrogen purging technology is widely used in storage warehouses, unmanned industrial production sites, mines, oil tanks, petrochemical production workshops, control rooms and cabinets of power transmission and transformation systems, computer centers, equipment rooms, and ship cabins and engine rooms—places with flammable and explosive hazards. This technology replaces and reduces the oxygen concentration in these enclosed spaces to the lower limit of the flammability limit, disrupting the oxygen requirement for combustion and thus preventing the formation of a combustion chain reaction. This "inertization protection" method can also be used for the routine safety maintenance of valuable materials, archives, cultural relics, and military equipment, serving to prevent corrosion and pollution.

[0003] The enclosed space that is filled with inert nitrogen-rich gas for "inertization protection" is called an inertized enclosed space (hereinafter referred to as "enclosed space").

[0004] Mechanical nitrogen filling is the use of air separation equipment (referred to as "nitrogen-oxygen separation unit" in this article) to remove oxygen from the air and enrich nitrogen components in the air to form the required high-purity nitrogen-rich gas. The high-purity nitrogen enriched from the air is then filled into a designated sealed space and location through a gas pipeline. The air separation equipment for producing nitrogen mainly includes the following types: (1) Nitrogen generator: ① PSA pressure swing adsorption nitrogen generator, which uses air as raw material and carbon molecular sieve as adsorbent. It uses the principle of pressure swing adsorption and utilizes the selective adsorption of oxygen and nitrogen by carbon molecular sieve to separate nitrogen and oxygen. Its process flow is as follows: the air first passes through an air filter to remove dust and mechanical impurities and then enters an air compressor to be compressed to the required pressure. After oil removal, water removal, and dust removal purification treatment, clean compressed air is output. The clean air enters the working adsorption tower. When passing through the molecular sieve, oxygen, carbon dioxide and water are adsorbed by it. The gas flowing to the outlet is nitrogen. Another tower (desorption tower) allows the adsorbed oxygen, carbon dioxide and water to be released from the micropores of the molecular sieve and discharged into the atmosphere. The two towers operate alternately to complete nitrogen-oxygen separation, continuously outputting nitrogen gas with a purity of up to 99.5%; ② High-pressure membrane nitrogen generators utilize the different permeation and diffusion rates of oxygen and nitrogen in air separation membranes for deoxygenation and nitrogen enrichment. It consists of a compressor, refrigerated dryer, filter, air buffer tank, heater, hollow fiber membrane, pipes, and valves. Its basic process includes: compressed air is compressed, dried, filtered, and heated before entering the membrane separator. Water vapor, carbon dioxide, and oxygen in the air rapidly permeate through the membrane wall and are enriched and discharged on the other side; nitrogen permeates through the membrane wall at a relatively slower rate and is enriched in the membrane. The enriched nitrogen is then used as the product gas and transported to enclosed spaces and other application locations. The difference between a high-pressure membrane nitrogen generator and an oxygen generator lies in the target product gas. When oxygen is considered the product gas, it can be considered an oxygen generator; when nitrogen is considered the product gas, it can be considered a nitrogen generator; ③ Atmospheric pressure membrane nitrogen generators utilize the different permeation and diffusion rates of oxygen and nitrogen in air separation membranes for deoxygenation and nitrogen enrichment. It typically consists of a fan, dryer, filter, hollow fiber membrane, and vacuum pump. The basic process flow includes: air from a closed space is drawn in by the fan, dried, filtered, and then enters the membrane separator. Water vapor, carbon dioxide, and oxygen in the air rapidly permeate through the membrane wall under the negative pressure of the vacuum pump, entering the other side of the membrane where they are enriched, removed, and discharged. Nitrogen permeates through the membrane wall at a relatively slow rate and is enriched within the membrane. The enriched nitrogen is then used as the product gas and transported to closed spaces or other locations requiring inerting protection.

[0005] (2) VPSA deoxygenation nitrogen generator: This type of generator uses carbon molecular sieves to selectively adsorb nitrogen and oxygen to separate them. Unlike the PSA carbon molecular sieve nitrogen generator, it uses atmospheric pressure adsorption and vacuum desorption to separate oxygen and nitrogen. It typically includes a fan, carbon molecular sieve adsorption tower assembly, vacuum pump, control valves, and pneumatic power source. The basic process flow is as follows: air in a closed space is drawn in by a fan and enters the pressure swing adsorption tower through the inlet valve. Oxygen molecules in the air are adsorbed by the carbon molecular sieves and then desorbed and discharged under vacuum. Unadsorbed nitrogen gas passes through the adsorption bed and accumulates at the top of the adsorption tower, then is returned to the closed space through the outlet valve. The deoxygenator usually uses two towers connected in parallel, alternating between atmospheric pressure adsorption and vacuum desorption regeneration to obtain a continuous nitrogen-rich gas flow.

[0006] (3) Oxygen generators: ① PSA oxygen generator. It uses the selective adsorption characteristics of zeolite molecular sieves for nitrogen and oxygen and the difference in adsorption capacity under different pressure conditions to separate oxygen and nitrogen. It removes oxygen by pressurization adsorption and depressurization desorption and produces nitrogen. It generally includes an air compressor, refrigerated dryer, air filter, dryer, air buffer tank, pressure swing adsorption tower group, nitrogen buffer tank, etc. Its basic process flow includes: after the air is compressed by the air compressor, it enters the air buffer tank after dust removal, oil removal and drying. After pressurization, drying and filtration, the clean air enters the pressure swing adsorption tower through the air inlet valve. The tower pressure increases, and the nitrogen molecules and carbon dioxide in the compressed air are adsorbed by the zeolite molecular sieve. When the adsorption is saturated, the nitrogen generated during natural depressurization desorption is discharged through the outlet valve at the bottom of the adsorption tower. The unadsorbed oxygen passes through the adsorption bed and is discharged through the outlet valve at the top of the adsorption tower; ② VPSA oxygen generator. This method utilizes the selective adsorption characteristics of zeolite molecular sieves for nitrogen and oxygen, and the differences in adsorption capacity under different pressure conditions, to separate oxygen and nitrogen. Unlike PSA oxygen generators, it employs atmospheric pressure adsorption and vacuum desorption to separate oxygen and nitrogen. It typically includes an atmospheric pressure fan, carbon molecular sieve adsorption tower assembly, vacuum pump, control valves, and pneumatic power source. The basic process flow involves: air in a sealed space is drawn in by a fan and enters the pressure swing adsorption tower through an inlet valve. Nitrogen molecules and carbon dioxide in the air are adsorbed by the zeolite molecular sieves. When adsorption is saturated, vacuum depressurization and desorption occur, producing nitrogen gas which is discharged through the outlet valve at the bottom of the adsorption tower. Unadsorbed oxygen passes through the adsorption bed and is discharged through the outlet valve at the top of the adsorption tower. Oxygen generators using pressure swing adsorption typically employ two towers in parallel, alternating between adsorption and desorption regeneration to obtain a continuous high concentration of oxygen and nitrogen mixed with carbon dioxide. The nitrogen mixed with carbon dioxide produced by the oxygen generator can be used as the product gas for inerting protection.

[0007] In practical applications, the common drawbacks of the above-mentioned equipment are: ① High energy consumption during nitrogen generation systems, especially PSA pressure swing adsorption technology which requires special equipment management, resulting in high operating costs and relatively high maintenance difficulty. ② Low nitrogen content in the nitrogen produced by oxygen generation equipment, which cannot meet the inerting requirements.

[0008] In recent years, the "VRM (Vacuum Rotary Humidification Nitrogen Generation)" technology and integrated equipment, developed based on the "vacuum rotary humidification nitrogen generation" process, have become a rapidly popular nitrogen generation technology. This technology, with its low energy consumption, operation at atmospheric pressure, lack of pressure vessel control, and ability to retain moisture and carbon dioxide in confined spaces, is particularly suitable for rapid circulating nitrogen generation in confined spaces. The basic principle of "vacuum rotary humidification nitrogen generation" is to connect the confined space requiring nitrogen filling and the nitrogen generation equipment through pipelines to form a closed-loop gas circulation system. Taking a grain stack as an example, a sealed space for nitrogen inerting protection and controlled atmosphere pest control, a pipeline is connected from the product gas outlet of the nitrogen generator to the upper part of the sealed grain space (used to output product gas nitrogen, referred to as the product gas nitrogen "exhaust pipeline"). Another pipeline is led from the lower part of the sealed grain space to the raw material gas inlet of the nitrogen generator (used to extract low-concentration nitrogen from the sealed storage area into the equipment as raw material gas, referred to as the nitrogen tail gas "return pipeline"). The nitrogen generator, the sealed space, the exhaust pipeline, and the return pipeline together constitute a closed-loop nitrogen separation and purification system. The exhaust fan and vacuum pump in the equipment create a reciprocating flow of gas in the pipeline system. The composite molecular sieve in the gas path system separates nitrogen and oxygen from the gas flowing through it, thereby achieving nitrogen separation and nitrogen concentration repurification under normal pressure conditions.

[0009] The VRM humidifying nitrogen generation system operates at a pressure <0.1MPa, does not require reporting or control of special pressure equipment, has a maximum output concentration of humidifying nitrogen ≥99.5%, and a humidity and carbon dioxide circulation retention rate ≥95.0% within the sealed space. In other words, the nitrogen output from the VRM nitrogen generation equipment is actually a mixture containing inert gases such as water vapor and carbon dioxide from the sealed space. The following similar concepts and descriptions of "nitrogen" are the same as the concepts and meanings of "nitrogen-rich mixture" and "nitrogen-rich gas," and "nitrogen storage unit" is the same as "nitrogen-rich mixture storage unit," etc.

[0010] The main structural components of a VRM nitrogen generator include: a gas ring blower, a composite molecular sieve adsorption tower group containing zeolite molecular sieves, a dry vacuum pump, a cooling system, and a control system. Its working principle is based on an "atmospheric pressure adsorption + vacuum desorption" operating mode. The composite molecular sieve adsorbs oxygen from the air, and the blower serves as the power device for gas extraction and transportation. Oxygen molecules are adsorbed by the composite molecular sieve, then removed and discharged into the air. The vacuum pump desorbs and discharges the extracted nitrogen components. In other words, the process of "blower extraction and transportation of gas into a closed space into the adsorption tower + composite adsorption tower adsorption of nitrogen + vacuum pump desorption of nitrogen and transportation back to the closed space" achieves the separation of nitrogen and oxygen in the raw gas. Vacuum pressure rotary adsorption nitrogen generators typically use two sets of adsorption towers connected in parallel. According to the pre-programmed control system, the four operating steps of atmospheric pressure adsorption, purging, vacuum desorption, and pressure equalization are continuously performed on the zeolite molecular sieve according to process requirements to complete nitrogen-oxygen separation and obtain the required nitrogen.

[0011] With the widespread application of VRM nitrogen generators, although this technology has solved the problem of the incompatibility between low energy consumption and high purity in other equipment, it still has the following technical blind spots and process performance defects in application, just like other nitrogen and oxygen generators: VRM humidifying nitrogen generators are based on the "vacuum rotary humidifying nitrogen generator" process technology. In the process of nitrogen separation and purification of gas in a closed space, it can achieve a humidity and carbon dioxide circulation retention rate of ≥95.0% inside the closed space. In actual work, it has been found that the gas composition from different inerting protection closed spaces may be different. In particular, in multiple inerting protection sites connected in series or parallel, due to the different areas, volumes, and equipment and materials arranged in different sites, the air humidity and carbon dioxide concentration distribution at different points may also be different. This directly leads to the fact that the raw material gas composition obtained by the VRM humidifying nitrogen generator from the closed space is not completely the same. This directly leads to the inability to continuously maintain a stable content of moisture and carbon dioxide in the output product gas. This affects the homogeneity and consistency of the content of each component of the nitrogen-rich gas filled in several inerting protection sites, and affects the accurate monitoring and control in the circulating inerting protection process.

[0012] (2) In the case of a closed space, the series of technologies provided by the patented technologies ① Method for Packaging and Stacking of Agricultural Products in Mechanical Modified Atmosphere Mode (202010643448.0), ② A Method for Rapid Mechanical Deoxygenation and Nitrogen Enrichment in a Closed Space (2020112130976), and ③ A Method for Improving the Efficiency of Mechanical Nitrogen Filling for Insect Prevention in Whole Warehouse Mode (2021109382622) are connected to the raw material gas inlet and nitrogen outlet of the air separation device through the inlet and outlet gas pipes. The circulating (circulating) nitrogen generation technology can quickly achieve the nitrogen concentration target of nitrogen filling and modified atmosphere. However, when facing multiple application scenarios or closed spaces of different sizes, if any closed unit has nitrogen leakage, concentration decay, or needs to be partially purged with nitrogen, the nitrogen generation system needs to be activated quickly and synchronously. In this case, the equipment system must be in a continuous and uninterrupted operating state to respond point-to-point to each closed unit, and the energy consumption during the process remains high.

[0013] (3) When facing application scenarios that require the filling of high-purity nitrogen, if nitrogen is filled into the confined space or flammable and explosive sensitive sites in one direction for inerting protection by displacement method or purging method, the nitrogen generating equipment needs to run continuously to output nitrogen without interruption, and the equipment operating cost is too high. Summary of the Invention

[0014] In view of this, it is necessary to provide an interactive, enhanced nitrogen separation and purification system to solve the problems of unstable component content in the nitrogen-rich gas output by existing nitrogen-oxygen separation equipment, the need for continuous operation to meet the needs of each closed unit, and high system energy consumption.

[0015] This invention provides an interactive, cyclic, and enhanced-output nitrogen separation and purification system. Following a vacuum rotary humidification nitrogen generation process, the nitrogen-oxygen separation unit and the inerted space are interconnected via a product gas nitrogen exhaust pipe and a tail gas return pipe to form a closed-loop nitrogen separation and purification system. The nitrogen-rich gas generated by the nitrogen-oxygen separation unit flows through the product gas exhaust outlet and the product gas nitrogen exhaust pipe to the inerted space. The low-concentration nitrogen gas in the closed space, whose concentration has decreased, is returned as tail gas to the nitrogen-oxygen separation layer of the nitrogen-oxygen separation unit for recirculation and repurification. A nitrogen-rich gas is connected in series in the product gas exhaust pipe between the nitrogen-oxygen separation unit and the inerted space. The nitrogen-rich gas ring-polymerization module includes a gas storage unit for conveying and buffering nitrogen-rich gas. The gas storage unit has a set of inlet and outlet holes, which are connected in series with the nitrogen exhaust pipe of the product gas in the system. The inner width of the gas storage unit at the maximum cross-section is not less than the inner diameter of the product gas exhaust pipe. Under the drive of the fan and vacuum pump in the closed-loop nitrogen separation and purification system, the nitrogen-rich product gas generated by the nitrogen-oxygen separation unit flows sequentially through the nitrogen exhaust pipe between the nitrogen-oxygen separation unit and the gas storage unit, the gas storage unit in the nitrogen-rich gas ring-polymerization module, and the nitrogen exhaust pipe between the gas storage unit and the closed space before entering the closed space. During the process of the nitrogen-rich product gas flowing through the above three sections with different cross-sectional areas, the gas Reynolds number changes and "turbulence enhancement effect" is formed.

[0016] Furthermore, the gas storage unit in the nitrogen-rich gas cyclic polymerization module has another set of inlet and outlet ports, which connect the gas storage unit in series to the tail gas return pipeline that leads from the sealed space to the feed gas inlet of the nitrogen-oxygen separation unit. Each inlet and outlet port on the gas storage unit is connected to a pipeline control valve. The product gas outlet and feed gas inlet of the nitrogen-oxygen separation unit are connected to the gas storage unit through nitrogen exhaust pipeline and tail gas return pipeline, respectively, forming a closed-loop "nitrogen-rich gas circulation purification subsystem". In this subsystem, the gas storage unit is both the source of the feed gas for the nitrogen-oxygen separation unit and the accumulation point of its output product gas. The gas storage unit and the sealed space are also connected through nitrogen exhaust pipeline and tail gas return pipeline to form a closed-loop "nitrogen-rich gas inerting protection and nitrogen tail gas return subsystem". At this point, the gas storage unit is both the source of nitrogen-rich gas for this subsystem and the collection point for nitrogen-rich gas exhaust gas extracted and replaced from the closed space. By opening or closing different pipeline control valves and their combinations, the two subsystems can either operate interactively through the same gas storage unit or operate independently. The nitrogen-rich gas circulation module plays a role in stabilizing the pressure and relaying the operation of the system.

[0017] Furthermore, the gas storage unit of the nitrogen-rich gas cyclic polymerization module is equipped with a gas concentration sensor. By setting the threshold of the highest oxygen concentration or the lowest nitrogen concentration in the gas storage unit, the nitrogen-oxygen separation unit can be automatically triggered and started / stopped. During the period when the nitrogen-oxygen separation unit is stopped or operating intermittently, the "nitrogen-rich gas inerting protection and nitrogen tail gas return subsystem" can operate independently in a cycle, and the nitrogen-rich gas stored in the gas storage unit can continuously complete the effective delivery and supply of inerting protection sealed space.

[0018] Furthermore, the nitrogen-rich gas cyclopolymerization module comprises at least two sets of gas storage components connected in parallel.

[0019] Furthermore, the nitrogen-rich gas cyclopolymerization module comprises at least two sets of gas storage devices connected in series.

[0020] Furthermore, both the nitrogen-rich gas inerting protection and reflux subsystem and the nitrogen-rich gas circulation purification subsystem are equipped with fans capable of driving gas flow.

[0021] Furthermore, a confined space is a closed space that needs to be filled with nitrogen-rich gas for inerting protection, including production sites, warehouses, process control rooms and pipeline systems, underground spaces, carriages, compartments, engine rooms or containers.

[0022] Furthermore, the gas storage component is a hollow gas storage tank or an expandable flexible air bladder. The inner width at the maximum cross-section of the gas storage component is not less than 3.5 times the inner diameter of the product gas delivery pipe. The distance between the inlet and outlet of the gas storage component that connects to the gas delivery pipe is not less than 200cm. The gas buffered by the hollow gas storage tank or expandable flexible air bladder can enhance the output of nitrogen-rich gas from the system and compensate for its concentration.

[0023] Furthermore, a gas pressure sensor is installed in the gas storage unit. By setting the threshold of the highest or lowest gas pressure in the gas storage unit, the nitrogen-oxygen separation unit can be automatically triggered and started / stopped.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) An interactive circulation, output-enhanced nitrogen separation and purification system, in the space where nitrogen and oxygen are separated and nitrogen is used for inerting protection, the nitrogen generation equipment system and the application scenario of filling nitrogen for inerting protection are respectively set as a nitrogen-rich gas inerting protection and reflux subsystem and a nitrogen-rich gas circulation purification subsystem. The two circulation systems can operate independently, but are connected to each other by sharing the same "nitrogen-rich gas circulation module". The system repeatedly extracts the tail gas of nitrogen-rich gas in the inerting protection space as the raw material gas of the nitrogen-oxygen separation unit for circulation reflux and repurification, thereby continuously improving the nitrogen purity of the output nitrogen-rich gas; by using a gas storage tank or a retractable flexible air bag to make a gas storage component for conveying or buffering nitrogen-rich gas in series in the product gas discharge pipeline of the nitrogen-oxygen separation unit, at the maximum cross-section of the gas storage component When the inner width of the gas is not less than 3.5 times the inner diameter of the product gas exhaust pipe, and the distance between the inlet and outlet of the product gas exhaust pipe on the gas storage device is not less than 200 cm, the nitrogen-rich product gas undergoes a change in the Reynolds number and a "turbulence enhancement effect" as it passes through the three-stage process of "gas exhaust pipe → gas ring polymerization module → gas exhaust pipe and enters the closed space" with different cross-sectional areas. This makes the components in the nitrogen-rich mixed product gas containing water vapor and carbon dioxide obtained by vacuum rotary humidification nitrogen generation process and zeolite molecular sieve adsorption layer more uniform, which is beneficial to improving the control accuracy and effect of inerting protection. Even if there are differences in the concentration and composition of the tail gas fed back from different control points in the closed space, it can correct the fluctuations in the concentration values ​​of each component in the output product gas caused by the above differences, and avoid the occurrence of unstable and nonlinear concentration monitoring data.

[0025] (2) The present invention provides an interactive circulation and output-enhanced nitrogen separation and purification system, which sets the nitrogen generation equipment system and the application scenario of nitrogen filling for inerting protection as a nitrogen-rich gas inerting protection and reflux subsystem and a nitrogen-rich gas circulation purification subsystem, respectively. The two circulation systems can operate independently but share the same "nitrogen-rich gas circulation module", forming a circulation nitrogen filling system in which "double rings cross and overlap, and four gases converge from the same source" through gas storage components between the two loops. The nitrogen-enriched gas cyclic polymerization module effectively connects the two loops in an interactive, enhanced nitrogen separation and purification system. It also serves as a buffer and pressure regulator for the nitrogen generated by the system, as well as a relay for its delivery. This module plays a crucial role in maintaining nitrogen output quality, extending output distance, expanding the coverage of the nitrogen delivery network, and enhancing the safety of nitrogen delivery in various nitrogen-filling application scenarios that are complex in structure, long in distance, and widely distributed. It also stabilizes the pressure and relays the operation of the circulating nitrogen-enriched gas and the inerted protective tail gas extracted from the confined space. Furthermore, it helps improve the mixing degree between the components in the output product gas and the consistency of gas concentration, thereby increasing the continuity and stability of process concentration monitoring data.

[0026] (3) The present invention provides an interactive, cyclic, and output-enhanced nitrogen separation and purification system. By installing an oxygen or nitrogen concentration sensor in the gas storage unit of the nitrogen-rich gas cyclic polymerization module, the oxygen or nitrogen volume percentage concentration in the gas storage unit is used as the concentration threshold for automatic start-up and shutdown of the nitrogen-oxygen separation unit in the "nitrogen-rich gas circulating purification subsystem". This allows the nitrogen-rich mixed gas buffered in the gas storage unit to maintain the independent and effective operation of the "nitrogen-rich gas inerting protection and reflux subsystem" during the shutdown and discontinuous operation of the nitrogen-oxygen separation unit. This forms a "one-to-one" response mode where the start-up and shutdown of the nitrogen-oxygen separation unit are only related to the oxygen concentration in the nitrogen-rich gas cyclic polymerization module. In this mode, during the shutdown and discontinuous operation of the nitrogen-oxygen separation unit, the nitrogen-rich mixed gas buffered in the gas storage unit can still maintain the independent and effective operation of the "nitrogen-rich gas inerting protection and reflux subsystem". The gas can also ensure the independent and continuous operation of the "nitrogen-rich gas inerting protection and reflux subsystem". If the oxygen concentration exceeds the maximum allowable threshold in any closed space that requires inerting protection in the system, the pipeline control valve and fan on the nitrogen-rich gas circulation purification subsystem will start and transport the nitrogen-rich mixed gas in the gas storage unit to the designated location. This "one-to-many" start and stop response mode can avoid the "one-to-many" start and stop response mode that a nitrogen-oxygen separation unit has to meet the needs of multiple gas consumption spaces. The start or stop of the nitrogen-oxygen separation unit is only related to the oxygen or nitrogen concentration in the gas storage unit and responds in a "one-to-one" manner, reducing the occurrence of continuous and uninterrupted operation of the nitrogen generation equipment, and greatly reducing the operating time, start frequency and operating energy consumption of the equipment system.

[0027] Even when facing multiple application scenarios or enclosed spaces of varying sizes, and even if any enclosed unit experiences nitrogen leakage or concentration decay requiring local nitrogen purging or replenishment, the presence of the gas storage component in the system eliminates the need for the nitrogen generator to maintain continuous operation, thus avoiding various manpower, maintenance, and energy costs.

[0028] Effective isolation is achieved between the nitrogen-oxygen separation unit and the enclosed space where nitrogen is consumed. In the event of any fire risk in the nitrogen consumption space or the main equipment, it is difficult for the pipelines to penetrate and affect each other.

[0029] (4) The nitrogen separation and purification system of the present invention, which features interactive circulation and enhanced output, can compensate for nitrogen output when the nitrogen-oxygen separation unit is shut down or when the instantaneous demand for nitrogen in the inerted and protected sealed space increases, thereby improving the efficiency of system operation. Taking the volume of the designed nitrogen-rich gas storage device as M (cubic meters) as an example, without increasing equipment configuration or incurring new energy consumption, the maximum instantaneous output flow rate of nitrogen-rich gas can be increased from its rated output flow rate Vn to Vn+M. Attached Figure Description

[0030] The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 is a schematic structural diagram of an interactive, cyclic, output-enhanced nitrogen separation and purification system according to the present invention; Figure 2 is a schematic structural diagram of the parallel connection of gas storage components in the nitrogen-rich gas cyclic polymerization module according to the present invention; Figure 3 is a schematic structural diagram of the series connection of gas storage components in the nitrogen-rich gas cyclic polymerization module according to the present invention. In the figures, 100 is the nitrogen-rich gas cyclic polymerization module; 110 is the gas storage component; 200 is the nitrogen-rich gas inerting protection and reflux subsystem; 210 is the enclosed space; 300 is the nitrogen-rich gas circulating purification subsystem; 310 is the nitrogen-oxygen separation unit; and 320 is the gas replenishment component. Detailed Implementation

[0031] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0032] This embodiment presents an interactive, cyclic, and output-enhanced nitrogen separation and purification system in the field of mechanical nitrogen filling technology. It includes a nitrogen-rich gas cyclic polymerization module, comprising a gas storage unit for conveying and buffering nitrogen-rich gas. A gas storage unit with a set of inlet and outlet ports is connected in series in the product gas exhaust pipe between the nitrogen-oxygen separation unit and the inerted, protected sealed space. These inlet and outlet ports are connected in series with the nitrogen exhaust pipe of the product gas in the system. The inner width of the gas storage unit at its maximum cross-section is not less than the inner diameter of the product gas exhaust pipe. Driven by a fan and vacuum pump in the closed-loop nitrogen separation and purification system, the nitrogen-rich product gas generated by the nitrogen-oxygen separation unit flows sequentially through the nitrogen exhaust pipe between the nitrogen-oxygen separation unit and the gas storage unit, the gas storage unit in the nitrogen-rich gas cyclic polymerization module, and the nitrogen exhaust pipe between the gas storage unit and the sealed space before entering the sealed space. During the flow of the nitrogen-rich product gas through these three sections with different cross-sectional areas, a change in the gas Reynolds number and a "turbulence enhancement effect" occur.

[0033] The gas storage unit has another set of inlet and outlet ports. Each inlet and outlet port on the gas storage unit is connected to a pipeline control valve. The gas storage unit is connected in series with the tail gas return pipeline, which leads from the sealed space to the feed gas inlet of the nitrogen-oxygen separation unit. The nitrogen-rich gas circulation purification subsystem connects the product gas outlet and feed gas inlet of the nitrogen-oxygen separation unit to the gas storage unit via nitrogen exhaust pipelines and tail gas return pipelines, forming a closed-loop "nitrogen-rich gas circulation purification subsystem." The nitrogen-oxygen separation unit can produce nitrogen and discharge oxygen using a vacuum rotary humidification nitrogen generation process. In this subsystem, the gas storage unit serves as both the source of the feed gas for the nitrogen-oxygen separation unit and the collection point for its output product gas. Nitrogen-rich gas inerting protection and nitrogen tail gas return are also included. The flow subsystem includes a sealed space for inerting protection with nitrogen-rich gas, an exhaust pipe, and a return pipe. The sealed space is connected to a gas storage unit via the exhaust pipe to receive the nitrogen-rich gas. The sealed space is also connected to a nitrogen-oxygen separation unit via the return pipe to allow the exhaust gas displaced from the sealed space to be transported to the nitrogen-oxygen separation unit for recirculation and purification. The gas storage unit serves as both the source of the nitrogen-rich gas for this subsystem and the collection point for the nitrogen-rich gas exhaust gas extracted and displaced from the sealed space. By opening or closing different pipeline control valves and their combinations, the two subsystems can either operate interactively through the same gas storage unit or operate independently. The nitrogen-rich gas circulation module plays a role in stabilizing the pressure and relaying the operation of the system.

[0034] The nitrogen-rich gas cyclic polymerization module is equipped with a gas concentration sensor in its gas storage unit. By setting the threshold for the highest oxygen concentration or the lowest nitrogen concentration in the gas storage unit, the nitrogen-oxygen separation unit can be automatically triggered, started, and stopped. During the periods when the nitrogen-oxygen separation unit is stopped or operating intermittently, the "nitrogen-rich gas inerting protection and nitrogen tail gas reflux subsystem" can operate independently in a cyclical manner, and the nitrogen-rich gas stored in the gas storage unit can continuously complete the effective delivery and supply of inerting protection sealed space.

[0035] The nitrogen-rich gas cyclopolymerization module includes at least two sets of gas storage units connected in series.

[0036] Both the nitrogen-enriched gas inerting protection and reflux subsystem and the nitrogen-enriched gas circulation purification subsystem are equipped with pipeline control valves and fans. The pipeline control valves control the on / off state of the pipeline, and the fans drive the gas flow. Example 1:

[0037] The enclosed space 210 requiring inerting protection is similar to storage warehouses, mines, oil tanks, petrochemical production workshops, control rooms and control cabinets of power transmission and transformation systems, computing centers, equipment rooms, as well as spaces containing flammable and explosive hazards such as ship cabins, engine rooms, archives and cultural relics, and military equipment. In this case, mechanical nitrogen filling technology is used to fill the system requiring protection with inert nitrogen gas, so that the oxygen concentration in the enclosed space drops to the lower limit of the flammability limit to prevent the combustion chain reaction. In this embodiment, according to the flammable and explosive gas composition in the enclosed space, and in accordance with the requirements of the group standard "Guidelines for Inerting Protection of Petrochemical Power Distribution Rooms and Cabinets" (T / CI1146-2025), the oxygen concentration in the enclosed space 210 requiring inerting protection must not exceed the maximum limit oxygen concentration. The maximum allowable oxygen concentration threshold set for the enclosed space 210 is 2%.

[0038] Using a VRM (Vacuum Rotation Maintain-humidity) nitrogen generation system as the nitrogen-oxygen separation unit 310, the sealed space 210 and the nitrogen generation equipment are connected by pipelines to form a closed-loop gas operation system. A vacuum pump within the equipment creates a reciprocating gas circulation within the pipeline system. A composite molecular sieve in the gas path system separates nitrogen and oxygen from the gas flowing through it, thus achieving nitrogen generation under normal pressure conditions. This is referred to as VRM normal pressure humidification nitrogen generation technology. The raw material gas inlet of the nitrogen-oxygen separation unit is drawn from the inerted sealed space by an exhaust fan and enters the zeolite molecular sieve layer of the nitrogen-oxygen separation unit for nitrogen and oxygen separation. The oxygen component in the raw material gas is directly discharged through the molecular sieve. The remaining moisture, carbon dioxide, and nitrogen components undergo adsorption by the zeolite molecular sieve layer and desorption by the vacuum pump to become nitrogen-rich product gas. This nitrogen-rich product gas enters the sealed space through the product gas discharge pipeline. The above process is repeated until the sealed space is fully sealed. The gas concentration in the enclosed space meets the requirements for inerting protection. In this embodiment, the nitrogen-rich gas ring-polymerization module 100 includes a gas storage component 110 for conveying and buffering nitrogen-rich gas. The gas storage component 110 is connected in series in the product gas discharge pipeline of the nitrogen-oxygen separation unit 310. The gas storage component 110 is a hollow gas storage tank or an expandable flexible gas bag. The inner width at the maximum cross-section of the gas storage component 110 is not less than 3.5 times the inner diameter of the product gas discharge pipeline. The distance between the inlet and outlet of the gas storage component 110 that connects to the gas delivery pipeline is not less than 200 cm. In this embodiment... The nitrogen-rich gas inerting protection and reflux subsystem 200 includes a sealed space 210 for inerting protection by filling with nitrogen-rich gas. The sealed space 210 is connected to a gas storage unit 110 via a product gas exhaust pipe to receive the nitrogen-rich gas. The tail gas displaced from the inerting protection space is transported to the raw material gas extraction and reflux pipe of the nitrogen-oxygen separation unit 310 for recirculation and repurification via a gas reflux pipe. The gas in the nitrogen separation and purification system flows between the nitrogen-rich gas recirculation purification subsystem 300 and the nitrogen-rich gas inerting protection and reflux subsystem 200. In cyclic operation, the nitrogen-rich gas generated by the nitrogen-oxygen separation unit 310 enters the inerting protection space through a three-stage process: "gas exhaust pipeline → gas cyclone module → gas exhaust pipeline". Due to the different cross-sectional areas of the three stages, the Reynolds number of the nitrogen-rich gas changes, resulting in a "turbulence enhancement effect". This effectively reduces and stabilizes the peak values ​​and frequencies of fluctuations in moisture and carbon dioxide concentrations in the nitrogen-rich mixture output by the nitrogen-oxygen separation unit caused by differences in air humidity and carbon dioxide concentration distribution at different locations in the sealed space 210. Example 2:

[0039] Similar to Example 1, the difference lies in that the nitrogen-oxygen separation unit 310 extracts gas from the gas storage unit 110 through a raw material gas intake pipe and separates the nitrogen and oxygen components. The nitrogen separated by the VRM humidifying nitrogen generation system is returned to the gas storage unit 110 through a nitrogen-rich gas exhaust pipe, while the separated oxygen is discharged into the atmosphere. The gas storage unit 110 serves as both the source of raw material gas for the VRM humidifying nitrogen generation system and a buffer and collection point for the product nitrogen gas. The nitrogen-oxygen separation unit 310, the raw material gas intake pipe, the nitrogen-rich gas exhaust pipe, and the gas storage unit 110 are interconnected to form a "nitrogen-rich gas circulation purification subsystem 300". At least one nitrogen delivery pipe and a circulation return pipe are respectively connected to the two symmetrical ends of the gas storage unit 110. The other ends of the nitrogen-rich product gas exhaust pipe and the circulation return pipe are respectively connected to any two symmetrical ends of the sealed space 210 for storing agricultural products. The nitrogen-rich product gas exhaust pipeline extracts nitrogen from the gas storage unit 110 and transports it to the sealed space 210 that needs inerting protection. The original gas inside the sealed space 210 is simultaneously replaced and returned to the nitrogen storage unit 110 through the circulation return pipeline. This constructs a "nitrogen-rich gas inerting protection and reflux subsystem 200" centered on the gas storage unit 110, which includes nitrogen storage, output and application of nitrogen for inerting protection.

[0040] The airtightness of the enclosed space is modified and tested in accordance with the relevant provisions of the People's Republic of China National Standard GB / T25229-2010 "Grain and Oil Storage - Airtightness Requirements for Flat Warehouses". The aforementioned exhaust and ventilation pipes are selected from plastic, rubber, or metal pipes with an inner diameter of 10-200mm according to the size of the enclosed space 210. Airflow-driven fans are installed in the pipes to meet the operational objectives of various gas-driven functions. In this embodiment, the nitrogen-oxygen separation unit 310 is selected from the "duplex nitrogen generator" series equipment produced by Wuhan Dongchang Storage Technology Co., Ltd. using VRM humidification nitrogen generation technology. The rated concentration of nitrogen output from the nitrogen generator is set to 99.5%, and the oxygen volume concentration in the gas storage unit 110 is set to 99.5%. When the concentration falls below this set threshold, the VRM humidification nitrogen generation system automatically starts. The system operates by extracting gas from the gas storage unit 110 via the raw gas intake pipe as raw gas for circulating oxygen removal. The nitrogen separated by the nitrogen generator is returned to the gas storage unit 110 via the nitrogen-enriched gas exhaust pipe to ensure that the nitrogen volume concentration inside is not lower than the set threshold. The maximum allowable oxygen concentration threshold set for the enclosed space 210, which requires inerting protection, is 2%. The drive fans on the nitrogen-enriched product gas exhaust pipe and the circulation return pipe are turned on. The nitrogen-enriched product gas exhaust pipe extracts the stored nitrogen from the gas storage unit 110 and transports it to the enclosed space 210. The gas displaced by the nitrogen in the enclosed space 210 is returned to the nitrogen storage unit 110 via the circulation return pipe. This cycle continues until the nitrogen concentration in the enclosed space 210 reaches the set standard.

[0041] In this embodiment, the nitrogen volume concentration in the "nitrogen storage device 110" can be set to a variety of values, such as 98.5%, 99.0%, 99.5%, 99.9%, or even higher. The maximum allowable oxygen concentration in the inerted and protected sealed space 210 is also set to 2%. When the drive fan on the nitrogen-rich product gas exhaust pipe and the drive fan on the circulation return pipe are turned on, the nitrogen-rich product gas exhaust pipe extracts and stores nitrogen from the storage device 110 and transports it to the sealed space 210. The oxygen concentration in the sealed space 210 reaches the set standard more quickly and easily.

[0042] In this embodiment, even if the maximum permissible oxygen concentration in the inerted and protected sealed space 210 is still set to 2%, the nitrogen volume concentration in the nitrogen storage device 110 can be set higher, for example, to exceed 99.9%. In this case, the rated concentration of nitrogen output from the nitrogen generator also needs to be increased to not less than 99.9%. In the above case, the mixed product gas nitrogen accumulation or the output flow rate can be increased by adding air from the external environment to the product gas discharge pipe between the nitrogen storage device 110 and the sealed space 210. The above operations still need to ensure that the oxygen concentration in the mixed product gas delivered to the sealed space after adding ambient gas is not higher than 2%.

[0043] In this embodiment, the nitrogen storage device 110 is connected in series in the product gas discharge pipeline of the nitrogen-oxygen separation unit. It serves as both the source of raw material gas for the "nitrogen-rich gas circulation purification subsystem 300" and the source of nitrogen for the "nitrogen-rich gas inerting protection and reflux subsystem 200 for nitrogen storage, output and application of nitrogen for inerting protection". It is the gathering place of nitrogen in the product gas of the nitrogen-rich gas circulation purification subsystem 300 and the gathering place of the gas that is replaced or extracted in the "nitrogen storage, output and application of nitrogen for inerting protection and reflux subsystem 200", presenting a circulation nitrogen filling system with "double-ring cross-overlapping and four gases converging from the same source" between the two circulation loops (see Figure 1). The raw gas inlet of the nitrogen-oxygen separation unit is drawn from the inerted and sealed space by an exhaust fan and enters the zeolite molecular sieve layer of the nitrogen-oxygen separation unit for nitrogen and oxygen separation. The oxygen component in the raw gas is directly discharged through the molecular sieve. The remaining moisture, carbon dioxide and nitrogen components are adsorbed by the zeolite molecular sieve layer and desorbed by the vacuum pump to become nitrogen-rich product gas. The nitrogen-rich product gas enters the inerted and sealed space through the product gas discharge pipeline. The above process is repeated to complete the circulation and repurification of nitrogen-rich gas.

[0044] In the "Nitrogen-Rich Gas Circulation Purification Subsystem", the gas storage unit 110 serves as both the source of the raw material gas for the nitrogen-oxygen separation unit and the collection point for its output product gas. In the "Nitrogen-Rich Gas Inerting Protection and Reflux Subsystem", the gas storage unit 110 serves as both the source of the nitrogen-rich gas in the inerting protection closed space and the collection point for the tail gas from which nitrogen-rich gas is extracted and replaced in the closed space. The two systems are interconnected through the gas storage unit 110, and the nitrogen-rich gas tail gas from the inerting protection closed space is recycled as the raw material gas for the nitrogen-oxygen separation unit, forming a secondary separation and purification effect of circulating the raw material gas. In addition to forming the aforementioned "turbulence enhancement effect" of gas flow, the system also plays a role in stabilizing and relaying the operation of the circulating nitrogen-rich gas and the inerting protection tail gas extracted from the closed space. It also helps to improve the mixing degree between the components in the output product gas and the consistency of gas concentration, and increases the continuity and stability of process concentration monitoring data.

[0045] Oxygen or nitrogen concentration sensors and gas pressure sensors are installed in nitrogen storage tanks or flexible gas bags. Based on the nitrogen concentration threshold set by the system and the sensor monitoring data, the start-up and shutdown operation of the equipment system is automatically controlled.

[0046] In this embodiment, several pipeline control valves are installed in the connecting pipelines of the nitrogen-rich gas circulation purification subsystem 300 and the nitrogen-rich gas inerting protection and reflux subsystem 200, as well as at the inlet and outlet ports of the nitrogen-oxygen separation device 310, the gas storage device 110, and the enclosed space 210 requiring inerting protection. The valve start-stop execution program is set according to the requirements of the control process. Example 3:

[0047] Similar to Embodiments 1 and 2, the difference lies in that an oxygen or nitrogen concentration sensor is installed in the gas storage component 110 of the nitrogen-rich gas cyclic polymerization module 100. The oxygen volume percentage concentration in the gas storage component 110 is set as the start threshold of the nitrogen-oxygen separation unit. When the oxygen volume percentage concentration in the gas storage component 110 is greater than or equal to the set value, the nitrogen-oxygen separation unit starts to operate. At this time, the pipeline control valve on the gas return pipeline used to extract nitrogen-rich gas tail gas between the inerted protective sealed space and the gas storage component 110, and the pipeline control valve on the nitrogen-rich product gas discharge pipeline between the gas storage component 110 and the inerted protective sealed space are closed. The pipeline control valve on the extraction return pipeline between the raw material gas inlet of the nitrogen-oxygen separation unit and the gas storage component 110, and the pipeline control valve on the nitrogen-rich product gas discharge pipeline between the product gas outlet of the nitrogen-oxygen separation unit and the gas storage component 110 are opened, forming a "one-to-one" response mode in which the start and stop of the nitrogen-oxygen separation unit are only related to the oxygen concentration in the nitrogen-rich gas cyclic polymerization module 100.

[0048] Oxygen and nitrogen concentrations are monitored using gas sampling, centralized monitoring, and direct sensing combined with wireless signal transmission by placing sensors at monitoring sites, respectively. Oxygen sensors manufactured by Henan Zhengzhou Beibo Electronics Co., Ltd. can be used, with a detection range of 0-30% VOL and a detection error of ±1.0% VOL; oxygen sensors manufactured by Hubei Jiaxin Co., Ltd. also have a detection range of 0-30% VOL and a minimum display value of 0.1% VOL. In this embodiment, a wireless oxygen concentration monitor manufactured by Wuhan Dongchang Storage Technology Co., Ltd. is selected, with a detection range of 0-25% VOL and a detection error of ±0.7% VOL.

[0049] During periods of inactivity or discontinuous operation of the nitrogen-oxygen separation unit, the nitrogen-rich mixed gas in the gas storage unit 110 ensures the independent and effective operation of the "nitrogen-rich gas inerting protection and reflux subsystem." At this time, the pipeline control valves and fans on the nitrogen-rich gas circulation purification subsystem activate when the oxygen volume percentage concentration in any enclosed space requiring inerting protection is greater than or equal to the set value of the enclosed space 210. This ensures that the nitrogen-rich mixed gas in the gas storage unit 110 is delivered to the designated location, forming a "one-to-many point" start-stop response mode where "one gas storage unit 110 satisfies multiple gas consumption spaces." Example 4:

[0050] Similar to Examples 1, 2, and 3, the difference lies in that in spaces with flammable and explosive hazards, such as those in the petrochemical industry, pneumatic conveying of powders, or special manufacturing sections, mechanical nitrogen purging technology is used to purge high concentrations of inert nitrogen onto the surfaces of the sensitive parts that need protection and contain flammable and explosive hazards, as well as into the gaps where flammable and explosive powders are conveyed via pneumatic conveying. This prevents the flammable and explosive powders on the sensitive parts or during the pneumatic conveying process from forming conditions for combustion and explosion.

[0051] The VRM humidifying nitrogen generation system is used as the nitrogen-oxygen separation unit 310, and a gas storage tank or flexible gas bag is used as the nitrogen storage component 110. The nitrogen-oxygen separation unit 310 extracts gas from the gas storage component 110 through the raw material gas intake pipe and separates the nitrogen and oxygen components. The separated nitrogen is returned to the gas storage component 110 through the nitrogen-rich gas exhaust pipe, and the oxygen separated by the VRM humidifying nitrogen generation system is discharged into the atmosphere. The gas storage component 110 is both the source of raw material gas for the VRM humidifying nitrogen generation system and the storage place of the product gas nitrogen of the VRM humidifying nitrogen generation system. The nitrogen-oxygen separation unit 310, the raw material gas intake pipe, the nitrogen-rich gas exhaust pipe and the gas storage component 110 are interconnected and constitute a "nitrogen-rich gas circulation purification subsystem 300".

[0052] At least one nitrogen delivery pipeline and one circulation return pipeline are connected to the two symmetrical ends of the gas storage unit 110. The other end of the nitrogen-rich product gas exhaust pipeline is connected to the work site that requires high concentration of nitrogen. The nitrogen-rich product gas exhaust pipeline delivers nitrogen from the gas storage unit 110 to the site where nitrogen needs to be consumed for purging or blows nitrogen into the conveyed powder to prevent combustion and explosion accidents. The circulation return pipeline is connected to a new nitrogen generator to replenish the pressure difference between the inside and outside of the "nitrogen-rich gas circulation purification subsystem 300" caused by the rapid consumption of nitrogen gas by inputting new nitrogen. Similarly, the air inlet of the circulation return pipeline directly draws air from the atmosphere to replenish the pressure difference between the "nitrogen-rich gas circulation purification subsystem 300" and the external environment caused by the rapid consumption of nitrogen gas.

[0053] A gas replenishment port is set up at any stage of the "nitrogen-rich gas circulation purification subsystem 300". A new nitrogen generator is connected to the gas replenishment port to replenish the pressure difference between the inside and outside of the "nitrogen-rich gas circulation purification subsystem 300" caused by the rapid consumption of nitrogen gas. Similarly, a gas replenishment port that directly draws gas from the atmosphere is set up in the "nitrogen-rich gas circulation purification subsystem 300" to replenish the pressure difference between the inside and outside of the system caused by the rapid consumption of nitrogen gas.

[0054] The aforementioned exhaust and ventilation pipes are selected based on the size of the enclosed space 210, using plastic, rubber, or metal pipes with an inner diameter of 10-200mm. Airflow-driven fans are installed within the pipes. In this embodiment, the nitrogen concentration for inerting protection and on-site nitrogen purging is set to 98%. The driving fans on the nitrogen-rich product gas exhaust pipe and the circulating return pipe are activated to complete the nitrogen transport operation. The nitrogen-oxygen separation unit 310 is selected from the "duplex nitrogen generator" series equipment manufactured by Wuhan Dongchang Storage Technology Co., Ltd. using VRM humidification nitrogen generation technology. The nitrogen output concentration of the nitrogen generator is set at 99.5%, and the nitrogen volume concentration in the "nitrogen storage unit 110" is set to >98%. When it falls below this critical value, the VRM humidification nitrogen generation system automatically starts, extracting gas from the storage unit 110 through the raw material gas intake pipe as raw material gas for circulating oxygen removal. The nitrogen separated by the nitrogen generator is then returned to the storage unit 110 through the nitrogen-rich gas exhaust pipe to ensure that its nitrogen volume concentration is not lower than the set critical value.

[0055] Oxygen or nitrogen concentration sensors and gas pressure sensors are installed in nitrogen storage tanks or flexible gas bags. Based on the nitrogen concentration threshold set by the system and the data monitored by the sensors, the start-up and shutdown of the equipment system are automatically controlled. This realizes two independent and overlapping systems: the start-up and shutdown of the nitrogen-oxygen separation unit 310 are only related to the nitrogen concentration threshold set in the gas storage component 110, and the points where nitrogen is consumed for purging or nitrogen is blown into the conveying powder are only related to the nitrogen concentration threshold set in the gas storage component 110. The "nitrogen-rich gas circulation purification subsystem 300" is the nitrogen supply unit, and the gas storage component 110, nitrogen conveying pipeline, and the work site that requires high concentration of nitrogen are connected together to form the nitrogen consumption unit.

[0056] In this embodiment, when nitrogen purging is carried out at flammable and explosive sites that require inerting protection and special manufacturing, the drive fan on the nitrogen-rich product gas exhaust pipeline is turned on to complete the nitrogen delivery and purging operation. The gas storage unit 110 in the system plays the role of gas storage, relay and pressure regulation. At the same time, it isolates and protects the nitrogen-oxygen separation unit 310 from the purging operation site that consumes nitrogen, preventing safety and accident hazards from causing mutual penetration through the pipeline system.

[0057] In this embodiment, several pipeline control valves are installed in various connecting pipelines of the system, as well as in the nitrogen-oxygen separation device, gas storage room, and gas transmission pipelines at work sites requiring inerting protection. The opening and closing actions of the valves are controlled according to the execution program. Example 5:

[0058] Similar to embodiments 1, 2, 3, and 4, the difference lies in that the gas storage component 110 is a hollow gas storage tank. The inner width at the maximum cross-section of the gas storage tank is not less than 3.5 to 10 times the inner diameter of the product gas exhaust pipe. The distance between the inlet and outlet of the gas storage component 110 that connects to the product gas exhaust pipe is set at 200 to 800 cm. High-pressure gas storage tanks, low-pressure gas storage tanks, and atmospheric pressure gas storage tanks are selected according to different application scenarios and pressure requirements. The materials include carbon steel, low-alloy steel, stainless steel, etc., to ensure the reliability of the tank's safety devices, gauges, and production process quality.

[0059] In this embodiment, a flexible airbag can be used instead of a gas tank. The inner width of the flexible airbag at its maximum cross-section is not less than 3.5 to 10 times the inner diameter of the product's gas delivery pipe. The distance between the inlet and outlet of the gas storage component 110 that connects to the product's gas delivery pipe is set at 200-800 cm. Depending on the application scenario and the pressure to be withheld, one or a combination of airbags, air bags, or sealed tents made of plastic curtains can be selected to inject and store gas. The aforementioned airbags, air bags, or sealed plastic tents are made by selecting one or more single-film or composite film products from nylon, polyvinyl chloride, polyethylene, polypropylene, nylon composite film, polyvinylidene fluoride, rubber, textiles, and non-woven fabrics, which have certain flexibility and airtightness. Based on the available placement space in the sealed space, they are cut to suitable sizes and manufactured using heat sealing, bonding, or sewing methods. The gaps and joints are sealed to create a bag-like object or a tent-like object with a three-dimensional structure that can store gas. Example 6:

[0060] Similar to Examples 1-5, the difference lies in that: the gas storage component 110 is composed of two or more gas storage tanks or flexible airbags arranged in parallel (see Figure 2). Figure 2 shows a schematic diagram of three gas storage tanks or flexible airbags connected in parallel. The parallel arrangement of 3+N (N being 1, 2, 3, 4, 5...) can be incrementally combined according to the pattern in Figure 2. The main pipeline connects to each gas storage component 110 via ventilation branch pipes. Each ventilation branch pipe is equipped with a valve to control the participation or withdrawal of each gas storage component 110 from the system. Each gas storage component 110 can be opened synchronously or independently according to the control program. The sequence is started to operate one, two or three of them in combination. At this time, the gas storage unit 110 connected in parallel is not only the source of raw gas for the "nitrogen-rich gas circulation purification subsystem 300", the source of nitrogen for the "nitrogen storage, output and application of nitrogen for inerting protection of nitrogen-rich gas inerting protection and reflux subsystem 200", but also the gathering place of nitrogen product gas in the nitrogen-rich gas circulation purification subsystem 300 and the gathering place of gas displaced in the "nitrogen storage, output and application of nitrogen for inerting protection of nitrogen-rich gas inerting protection and reflux subsystem 200", linking the two loops into a "double-loop cross-overlapping, four-gas convergence and common source" circulation nitrogen filling system (see Figure 2). By increasing the number of gas storage tanks and flexible gas bags required for the nitrogen-rich gas storage component 110, the amount of nitrogen buffered in the system can be increased. Even if the instantaneous demand for nitrogen at any point exceeds the maximum nitrogen generation capacity of the nitrogen generator, the output of nitrogen in the storage room can be effectively regulated to meet the instantaneous demand for nitrogen consumption. This also mitigates system safety risks without increasing equipment capacity. Example 7:

[0061] The process is basically the same as in Examples 1-5, except that the gas storage unit 110 is arranged in a series of two or more units (see Figure 3). In this case, the outlet end of the circulation return pipeline can be directly connected to the inlet end of the raw material gas intake pipe of the nitrogen-oxygen separation unit 310. The gas replaced by nitrogen in the sealed space 210 is returned to the nitrogen-oxygen separation unit 310 through the circulation return pipeline and the raw material gas intake pipe for cyclic nitrogen-oxygen separation. The series connection of 3+N units (N being 1, 2, 3, 4, 5...) is arranged in an incremental combination as shown in Figure 3. The interconnected gas storage units 110 serve as both the nitrogen accumulation point for the "Nitrogen-Rich Gas Circulation Purification Subsystem 300" and the nitrogen source for the "Nitrogen-Rich Gas Inerting Protection and Recirculation Subsystem 200" (nitrogen storage, output, and inerting protection using nitrogen). The gas storage units 110 function as gas storage, relay, and pressure regulators, while also isolating the nitrogen-oxygen separation unit 310 from the nitrogen-consuming enclosed space 210, preventing safety and accident hazards from penetrating each other through the pipeline system. Example 8:

[0062] Similar to Examples 1-7, except that the nitrogen-oxygen separation unit 310 in the nitrogen-rich gas circulation purification subsystem 300 uses a VPSA deoxygenator. The deoxygenator extracts gas from the gas storage unit 110 via a raw material gas intake pipe as raw material gas and separates the nitrogen and oxygen therein. The nitrogen separated by the deoxygenator is returned to the gas storage unit 110 via a product gas nitrogen exhaust pipe. The deoxygenator has a gas replenishment port, which draws in gas from outside the system to replenish the pressure difference between the inside and outside of the system formed during the deoxygenation and nitrogen production process in the nitrogen-rich gas circulation purification subsystem 300. Example 9:

[0063] Similar to Examples 1-7, except that the nitrogen-oxygen separation unit 310 in the nitrogen-rich gas circulating purification subsystem 300 uses a PSA pressure swing adsorption nitrogen generator, and another gas supply unit 320 is connected to the nitrogen-rich gas circulating purification subsystem 300. The gas supply unit 320 can be a gas storage tank or an air compressor. The gas supply unit 320 can introduce new gas to replenish the pressure difference between the inside and outside of the system formed during the oxygen removal process of the nitrogen-rich gas circulating purification subsystem 300. Example 10:

[0064] Similar to Examples 1-7, except that the nitrogen-oxygen separation unit 310 uses a membrane separation nitrogen generator, and another gas replenishment device 320 is connected to the nitrogen-rich gas circulating purification subsystem 300. Specifically, the gas replenishment device 320 can be a gas storage tank or an air compressor. The gas replenishment device 320 can introduce new gas to replenish the pressure difference between the inside and outside of the nitrogen-rich gas circulating purification subsystem 300 formed during the oxygen removal process. Example 11:

[0065] The process is basically the same as in Examples 1-7, except that the nitrogen-oxygen separation unit 310 is a PSA oxygen generator or a VPSA oxygen generator. The target product gas of the equipment is a mixture of nitrogen and carbon dioxide, and the oxygen produced by the equipment is discharged into the external environment as exhaust gas. Products from Zhejiang Zhongyi Gas Technology Co., Ltd. can be selected. Example 12:

[0066] The method is basically the same as in Examples 1-11, except that an oxygen or nitrogen concentration sensor is installed in the gas storage unit 110 of the nitrogen-rich gas cyclopolymerization module 100. The threshold for automatic triggering and starting of the nitrogen-oxygen separation unit is set when the oxygen volume percentage concentration in the gas storage unit 110 reaches 7.5%. This ensures that during the shutdown of the nitrogen-oxygen separation unit, the nitrogen-rich mixed gas in the gas storage unit 110 can still ensure the independent and effective operation of the "nitrogen-rich gas inerting protection and reflux subsystem". The drive fan on the nitrogen-rich product gas exhaust pipeline and the drive fan on the circulation return pipeline are turned on. The nitrogen-rich product gas exhaust pipeline extracts the stored nitrogen from the gas storage unit 110 and transports it to the sealed space. The gas replaced by nitrogen in the sealed space is returned to the nitrogen gas storage unit 110 through the circulation return pipeline. This cycle continues until the nitrogen concentration in the sealed space reaches the set standard. This method can play a role in preventing corrosion and contamination during the daily safety maintenance of storing valuable materials, archives, cultural relics, and military equipment.

[0067] In this embodiment, an oxygen or nitrogen concentration sensor is installed in the gas storage component 110 of the nitrogen-rich gas cyclopolymerization module 100. The oxygen volume percentage concentration in the gas storage component 110 can be set to 10% as the threshold for automatic triggering and start-up of the nitrogen-oxygen separation unit. This ensures that during the shutdown period of the nitrogen-oxygen separation unit, the nitrogen-rich mixture in the gas storage component 110 can still guarantee the independent and effective operation of the "nitrogen-rich gas inerting protection and reflux subsystem." This reduces the oxygen concentration to the lower limit of flammability in unmanned operating areas, mines, oil tanks, various sections of petrochemical production, power and information control rooms and control cabinets, computing centers, equipment rooms, and spaces with flammable and explosive hazards such as ship cabins and engine rooms, achieving the goal of destroying the oxygen condition among the three elements of combustion at a higher standard. Example 13:

[0068] The method is basically the same as in Examples 1-12, except that an oxygen or nitrogen concentration sensor is installed in the gas storage unit 110 of the nitrogen-rich gas cyclopolymerization module 100. The oxygen volume percentage concentration in the gas storage unit 110 can be set at a lower level as the threshold for automatic triggering and starting of the nitrogen-oxygen separation unit, such as 2.0, 3.0, 4.0, 5.0, 6.0 or 7.0%, to ensure that during the shutdown operation of the nitrogen-oxygen separation unit, the nitrogen-rich mixed gas in the gas storage unit 110 can still ensure the independent and effective operation of the "nitrogen-rich gas inerting protection and reflux subsystem".

[0069] The oxygen volume percentage concentration in the gas storage unit 110 can be set at a higher level as the threshold for automatic triggering and starting of the nitrogen-oxygen separation unit, such as 8.0, 9.0, 10.0, 11.0, 12.0, and 13.0%. This ensures that the oxygen volume percentage concentration in the output nitrogen mixture does not exceed 15%, and also ensures that the nitrogen-rich mixture in the gas storage unit 110 can still guarantee the independent and effective operation of the "nitrogen-rich gas inerting protection and reflux subsystem" during the shutdown period of the nitrogen-oxygen separation unit.

[0070] The oxygen volume percentage concentration threshold set above for automatic triggering and startup of the nitrogen-oxygen separation unit can be an integer or a decimal within a certain allowable error range. Example 14:

[0071] The embodiments are basically the same as those 1-13, except that: the enclosed space 210 and the nitrogen purging terminal can be 1, 2, 3...N (N is an integer greater than 3), and they can exist in parallel, series, or a combination of series and parallel connections. Example 15:

[0072] Similar to Examples 1-14, except that the outlet of the circulating return pipeline of the sealed space 210 is directly connected to the inlet of the raw material gas intake pipe of the nitrogen-oxygen separation unit 310. Nitrogen gas from the operating terminal requiring ventilation in the sealed space 210 is returned to the nitrogen-oxygen separation unit 310 through the circulating return pipeline and the raw material gas intake pipe for circulating nitrogen-oxygen separation. Then, high-purity nitrogen gas meeting the critical value is input into the gas storage unit 110 as a nitrogen consumption unit, thereby achieving the goal of energy saving. Example 16:

[0073] The process is essentially the same as in Examples 1-15, except that the oxygen or nitrogen concentration sensor in the gas storage unit 110 of the nitrogen-rich gas agglomeration module 100 can be replaced by a gas pressure sensor. The pressure setpoint of the nitrogen-rich gas in the gas storage unit 110 is used as the activation threshold for the nitrogen-oxygen separation unit. When the pressure of the nitrogen-rich gas in the gas storage unit 110 is lower than the set value (gas pressure safety threshold less than 1.6 MPa), the nitrogen-oxygen separation unit starts operating. The gas pressure sensor is a resistance remote pressure gauge. A resistance remote pressure gauge converts the measured value into an electrical value through an internal sliding resistor transmitter and transmits it to a secondary instrument located far from the measurement point, thereby achieving centralized detection and remote control. Operating environment conditions: -40~60℃, relative humidity not exceeding 85%.

[0074] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of the present invention.

Claims

1. A nitrogen separation and purification system with interactive circulation and enhanced output, characterized in that, Following the vacuum rotary humidification nitrogen generation process, the nitrogen-oxygen separation unit in the system is interconnected with the sealed space to be inerted via a product gas nitrogen exhaust pipe and a tail gas return pipe to form a closed-loop nitrogen separation and purification system. The nitrogen-rich gas generated by the nitrogen-oxygen separation unit flows through the product gas exhaust outlet and the product gas nitrogen exhaust pipe to the sealed space to be inerted. The low-concentration nitrogen gas in the sealed space, whose concentration has decreased, is then returned as tail gas to the nitrogen-oxygen separation layer of the nitrogen-oxygen separation unit for recirculation and repurification. A nitrogen-rich gas circulation module is connected in series in the product gas exhaust pipe between the nitrogen-oxygen separation unit and the sealed space to be inerted. The system includes a gas storage unit for conveying and buffering nitrogen-rich gas. The gas storage unit has a set of inlet and outlet ports and is connected in series with the nitrogen exhaust pipe of the product gas in the system. The inner width of the gas storage unit at its maximum cross-section is not less than the inner diameter of the product gas exhaust pipe. Under the drive of the fan and vacuum pump in the closed-loop nitrogen separation and purification system, the nitrogen-rich product gas generated by the nitrogen-oxygen separation unit flows sequentially through the nitrogen exhaust pipe between the nitrogen-oxygen separation unit and the gas storage unit, the gas storage unit in the nitrogen-rich gas ring module, and the nitrogen exhaust pipe between the gas storage unit and the closed space before entering the closed space. During the process of the nitrogen-rich product gas flowing through the above three sections with different cross-sectional areas, the gas Reynolds number changes and "turbulence enhancement effect" is formed.

2. The nitrogen separation and purification system with interactive circulation and enhanced output according to claim 1, characterized in that, The gas storage unit in the nitrogen-rich gas cyclic polymerization module has another set of inlet and outlet ports, which connect the gas storage unit in series to the tail gas return pipeline that leads from the sealed space to the feed gas inlet of the nitrogen-oxygen separation unit. Each inlet and outlet port on the gas storage unit is connected to a pipeline control valve. The product gas outlet and feed gas inlet of the nitrogen-oxygen separation unit are connected to the gas storage unit through the nitrogen exhaust pipeline and tail gas return pipeline, respectively, forming a closed-loop "nitrogen-rich gas circulation purification subsystem". In this subsystem, the gas storage unit is both the source of the feed gas for the nitrogen-oxygen separation unit and its output product gas. The gas storage unit and the sealed space are connected by nitrogen exhaust pipes and tail gas return pipes to form a closed loop "nitrogen-rich gas inerting protection and nitrogen tail gas return subsystem". At this time, the gas storage unit is both the source of nitrogen-rich gas for this subsystem and the collection point of nitrogen-rich gas tail gas extracted and replaced from the sealed space. By opening or closing different pipeline control valves and their combinations, the two subsystems can either operate interactively through the same gas storage unit or operate independently. The nitrogen-rich gas circulation module plays a role in stabilizing pressure and relaying the operation of the system.

3. A nitrogen separation and purification system with interactive circulation and enhanced output according to claim 2, characterized in that, The nitrogen-rich gas cyclic polymerization module is equipped with a gas concentration sensor in its gas storage unit. By setting the threshold for the highest oxygen concentration or the lowest nitrogen concentration in the gas storage unit, the nitrogen-oxygen separation unit can be automatically triggered, started, and stopped. During the periods when the nitrogen-oxygen separation unit is stopped or operating intermittently, the "nitrogen-rich gas inerting protection and nitrogen tail gas reflux subsystem" can operate independently in a cyclical manner, and the nitrogen-rich gas stored in the gas storage unit can continuously complete the effective delivery and supply of inerting protection sealed space.

4. A nitrogen separation and purification system with interactive circulation and enhanced output according to any one of claims 1-3, characterized in that, The nitrogen-rich gas cyclopolymerization module includes at least two sets of gas storage units connected in parallel.

5. A nitrogen separation and purification system with interactive circulation and enhanced output according to any one of claims 1-3, characterized in that, The nitrogen-rich gas cyclopolymerization module includes at least two sets of gas storage units connected in series.

6. A nitrogen separation and purification system with interactive circulation and enhanced output according to claim 1, characterized in that, Both the nitrogen-enriched gas inerting protection and reflux subsystem and the nitrogen-enriched gas circulation purification subsystem are equipped with fans capable of driving gas flow.

7. A nitrogen separation and purification system with interactive circulation and enhanced output according to claim 1, characterized in that, Enclosed spaces are enclosed spaces that need to be filled with nitrogen-rich gas for inerting protection, including production sites, warehouses, process control rooms and pipeline systems, underground spaces, carriages, cabins, engine rooms or containers.

8. A nitrogen separation and purification system with interactive circulation and enhanced output according to claim 1, characterized in that, The gas storage component is a hollow gas storage tank or an expandable flexible air bladder. The inner width of the gas storage component at its maximum cross-section is not less than 3.5 times the inner diameter of the product gas delivery pipe. The distance between the inlet and outlet of the gas storage component that connects to the gas delivery pipe is not less than 200cm. The gas buffered by the hollow gas storage tank or expandable flexible air bladder can enhance the output of nitrogen-rich gas from the system and compensate for its concentration.

9. A nitrogen separation and purification system with interactive circulation and enhanced output according to claim 3, characterized in that, A gas pressure sensor is installed in the gas storage unit. By setting the threshold of the highest or lowest gas pressure in the gas storage unit, the nitrogen-oxygen separation unit can be automatically triggered and started / stopped.

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