Nitrogen production plant

Abstract

The utility model discloses a kind of nitrogen production device, it is related to industrial nitrogen production technical field, wherein, nitrogen production device includes compressor, valve assembly, air filter and cold box, valve assembly includes first valve and second valve, the outlet end of first valve, the outlet end of second valve is connected after parallel and the inlet of compressor is communicated;The inlet end of first valve is connected in series with air filter;Cold box is communicated with the outlet of compressor, and cold box is used for purifying nitrogen gas.The utility model is switched by the double pass of valve assembly Design, realize the raw material gas type according to gas source condition flexible selection, when having low-purity nitrogen gas supply condition, energy consumption can be reduced, when there is no low-purity nitrogen gas supply, normal production can be ensured, compared with only air as single raw material of prior art, both nitrogen production energy consumption is reduced and supply stability is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of industrial nitrogen production technology, and in particular to a nitrogen production device. Background Technology

[0002] Nitrogen generators are a common piece of technical equipment in modern industry, used to provide nitrogen products to various industrial and mining enterprises. They are widely used in photovoltaic, chemical, battery, rubber, metallurgy and materials fields, providing various important applications such as gas power and atmosphere protection for various industrial sectors.

[0003] Common nitrogen generators use air as raw material and extract nitrogen from the air through steps such as compression, purification, cooling, liquefaction, and distillation. In this process, compressing and liquefying the air requires additional energy, so the energy consumption performance of a nitrogen generator is an important indicator for measuring its performance.

[0004] However, such nitrogen generators can only use air as raw material due to their process design. Since the nitrogen content in air is low, the energy required to produce nitrogen is also high.

[0005] Therefore, there is an urgent need for a new type of nitrogen generator to solve the problem of how to reduce the energy consumption of nitrogen production. Utility Model Content

[0006] The main purpose of this invention is to propose a nitrogen generation device that aims to solve the problem of how to reduce the energy consumption of nitrogen production.

[0007] To achieve the above objectives, the nitrogen generator proposed in this utility model includes a compressor, a valve assembly, an air filter, and a cold box. The valve assembly includes a first valve and a second valve. The outlet ends of the first valve and the second valve are connected in parallel and then connected to the inlet of the compressor. The inlet end of the first valve is connected in series with the air filter. The cold box is connected to the outlet of the compressor and is used to purify nitrogen.

[0008] In one embodiment, the valve assembly further includes a third valve and a fourth valve, the inlet end of the third valve and the inlet end of the fourth valve being connected in parallel and then connected to the outlet of the compressor; the nitrogen generator further includes a filter device, the inlet end of the filter device being connected in series with the outlet end of the third valve, the outlet end of the filter device and the outlet end of the fourth valve being connected in parallel and then connected to the cold box, the filter device being used to filter out carbon dioxide and water from the gas.

[0009] In one embodiment, the cold box includes a main heat exchanger and a distillation column. The outlet end of the filter device and the outlet end of the fourth valve are connected in parallel and communicated with the main heat exchanger. The distillation column is also connected to the main heat exchanger. The main heat exchanger is used to cool the incoming raw material gas. The distillation column is used to distill the cooled raw material gas and discharge the distilled nitrogen gas from the top and the lean nitrogen liquid from the bottom.

[0010] In one embodiment, the distillation column has a cavity containing multiple layers of sieve plates or packing.

[0011] In one embodiment, the cold box further includes a condenser connected to the top of the distillation column cavity via heat exchange pipes for heat exchange. The condenser is used to cool the nitrogen gas in the top of the distillation column cavity.

[0012] In one embodiment, the bottom of the distillation column is provided with a first opening, which is connected to the bottom of the cavity. The first opening is connected to the condenser through a first pipeline, and a throttling valve is provided on the first pipeline. The lean nitrogen liquid located at the bottom of the cavity flows into the condenser as a coolant through the first pipeline.

[0013] In one embodiment, the temperature of the lean nitrogen solution after passing through the throttling valve is 1 to 5°C lower than that of the nitrogen gas at the top of the distillation column.

[0014] In one embodiment, the top of the distillation column cavity is also connected to the main heat exchanger, and the distilled nitrogen gas discharged from the top of the distillation column cavity undergoes heat exchange in the main heat exchanger and is then discharged as product gas.

[0015] In one embodiment, the condenser is also connected to the main heat exchanger and the filter device in sequence through a second pipeline. The lean nitrogen liquid in the condenser is evaporated into waste nitrogen gas, which is then passed through the main heat exchanger via the second pipeline for heat exchange and then introduced into the filter device as regeneration gas.

[0016] In one embodiment, the top of the distillation column is provided with a liquid nitrogen supply port that communicates with the cavity, and the liquid nitrogen supply port is equipped with a switch.

[0017] The technical solution of this utility model adopts a valve assembly including a first valve and a second valve, and connects the outlet end of the first valve and the outlet end of the second valve in parallel to the compressor inlet, thereby forming a switchable dual gas source passage. The inlet end of the first valve is connected in series with an air filter to form a processing passage using air as the raw material gas, ensuring that the air must be purified to remove impurities before being used as raw material. The second valve forms a processing passage using low-purity nitrogen gas with a nitrogen content of 80% to 95% as the raw material gas. This low-purity nitrogen gas can be obtained from waste nitrogen gas from air separation units or from upstream industrial production processes such as pressure swing adsorption nitrogen generators. Based on this, when the upstream supply can provide low-purity nitrogen, the operator or system closes the first valve and opens the second valve, allowing the low-purity nitrogen to directly enter the compressor. Since the concentration of the target component in the raw material gas is higher than that of air, the energy required for compression and subsequent purification by the compressor can be reduced. Furthermore, the higher the nitrogen concentration in the raw material gas, the greater the energy savings in nitrogen production, thus effectively reducing nitrogen production energy consumption. When the upstream supply cannot provide low-purity nitrogen, the operator or system closes the second valve and opens the first valve, allowing air to enter the compressor after purification through an air filter, still ensuring a stable supply of nitrogen. In addition, by connecting the cold box to the compressor outlet, both types of raw materials can undergo compression and purification processes through the same compressor and cold box, ultimately obtaining high-purity nitrogen products.

[0018] Overall, this embodiment achieves flexible selection of raw material gas type according to gas source conditions through the dual-path switching design of the valve assembly. It reduces energy consumption when low-purity nitrogen is available and ensures normal production when low-purity nitrogen is unavailable. Compared with the existing technology that can only use air as a single raw material, it reduces nitrogen production energy consumption and ensures supply stability. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 A schematic diagram of an embodiment of the nitrogen generation device provided by this utility model.

[0021] Explanation of icon numbers: 1. Compressor; 2. Valve assembly; 21. First valve; 22. Second valve; 23. Third valve; 24. Fourth valve; 3. Air filter; 4. Cold box; 41. Main heat exchanger; 42. Distillation column; 43. Condenser; 44. Throttling valve; 5. Filtration device.

[0022] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0024] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0025] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0026] Nitrogen generators are a common piece of technical equipment in modern industry, used to provide nitrogen products to various industrial and mining enterprises. They are widely used in photovoltaic, chemical, battery, rubber, metallurgy and materials fields, providing various important applications such as gas power and atmosphere protection for various industrial sectors.

[0027] Common nitrogen generators use air as raw material and extract nitrogen from the air through steps such as compression, purification, cooling, liquefaction, and distillation. In this process, compressing and liquefying the air requires additional energy, so the energy consumption performance of a nitrogen generator is an important indicator for measuring its performance.

[0028] However, such nitrogen generators can only use air as raw material due to their process design. Since the nitrogen content in air is low, the energy required to produce nitrogen is also high.

[0029] Therefore, there is an urgent need for a new type of nitrogen generator to solve the problem of how to reduce the energy consumption of nitrogen production.

[0030] To address the aforementioned problems, this utility model proposes a nitrogen generation device.

[0031] Please see Figure 1 In one embodiment of the present invention, the nitrogen generating device includes a compressor 1, a valve assembly 2, an air filter 3, and a cold box 4. The valve assembly 2 includes a first valve 21 and a second valve 22. The outlet end of the first valve 21 and the outlet end of the second valve 22 are connected in parallel and connected to the inlet of the compressor 1. The inlet end of the first valve 21 is connected in series with the air filter 3. The cold box 4 is connected to the outlet of the compressor 1 and is used to purify nitrogen.

[0032] The technical solution of this utility model adopts a valve assembly 2 including a first valve 21 and a second valve 22, and connects the outlet end of the first valve 21 and the outlet end of the second valve 22 in parallel to the inlet of the compressor 1, thereby forming a switchable dual gas source passage. The inlet end of the first valve 21 is connected in series with the air filter 3 to form a processing passage with air as the raw material gas, ensuring that the air must be purified to remove impurities before being used as raw material. The second valve 22 forms a processing passage with low-purity nitrogen gas with a nitrogen content of 80% to 95% as the raw material gas. This low-purity nitrogen gas can be obtained from the waste nitrogen gas of the air separation unit or from upstream industrial production processes such as pressure swing adsorption nitrogen generation units. Based on this, when the upstream supply of low-purity nitrogen is available, the operator or system closes the first valve 21 and opens the second valve 22, allowing the low-purity nitrogen to directly enter the compressor 1. Since the concentration of the target component in the raw material gas is higher than that of air, the energy required for compression and subsequent purification using the compressor 1 can be reduced. Furthermore, the higher the nitrogen concentration in the raw material gas, the greater the energy savings in nitrogen production, thus effectively reducing nitrogen production energy consumption. When the upstream supply of low-purity nitrogen is unavailable (e.g., due to upstream shutdown for maintenance), the operator or system closes the second valve 22 and opens the first valve 21, allowing air to enter the compressor 1 after purification by the air filter 3, ensuring a stable supply of nitrogen. In addition, by connecting the cold box 4 to the outlet of the compressor 1, both types of raw materials can undergo compression and purification processes through the same compressor 1 and cold box 4, ultimately obtaining a high-purity nitrogen product.

[0033] Overall, this embodiment achieves flexible selection of raw material gas type according to gas source conditions through the dual-path switching design of valve assembly 2. It can reduce energy consumption when low-purity nitrogen is available and ensure normal production when low-purity nitrogen is unavailable. Compared with the existing technology that can only use air as a single raw material, it reduces nitrogen production energy consumption and ensures supply stability.

[0034] Please see Figure 1 In an embodiment of this utility model, the valve assembly 2 further includes a third valve 23 and a fourth valve 24. The inlet end of the third valve 23 and the inlet end of the fourth valve 24 are connected in parallel and then connected to the outlet of the compressor 1. The nitrogen generator further includes a filter device 5. The inlet end of the filter device 5 is connected in series with the outlet end of the third valve 23. The outlet end of the filter device 5 and the outlet end of the fourth valve 24 are connected in parallel and then connected to the cold box 4. The filter device 5 is used to filter out carbon dioxide and water from the gas.

[0035] In this embodiment, by including a third valve 23 and a fourth valve 24 in the valve assembly 2, and connecting their inlet ends in parallel to the outlet of the compressor 1, a switchable dual-passage structure is formed on the outlet side of the compressor 1. This corresponds to the first valve 21 and the second valve 22 on the inlet side of the compressor 1, enabling segmented control of the raw gas processing flow. Furthermore, by setting a filter device 5 and connecting its inlet end in series with the outlet end of the third valve 23, and simultaneously connecting its outlet end in parallel with the outlet end of the fourth valve 24 to the cold box 4, a selectively usable purification processing path is constructed. This filter device 5 can filter out carbon dioxide and water from the gas, effectively preventing these impurities from entering the cold box 4 and causing ice blockage or organic matter accumulation, thus ensuring the stable operation of the cold box 4.

[0036] Specifically, when the upstream supply is low-purity nitrogen gas free of carbon dioxide and water (such as polluted nitrogen gas obtained from cryogenic air separation), the operator or system closes the first valve 21 and the third valve 23, and opens the second valve 22 and the fourth valve 24, allowing the gas to bypass the filter device 5 and directly enter the cold box 4. This avoids the additional pressure loss caused by flowing through the filter device 5, while reducing unnecessary consumption of the desiccant in the filter device 5 and extending its service life. When the upstream supply is low-purity nitrogen gas containing carbon dioxide and water (such as low-purity nitrogen gas from a pressure swing adsorption (PSA) unit), (Because the PSA unit does not remove water and carbon dioxide from nitrogen), the operator or system closes the first valve 21 and the fourth valve 24, and opens the second valve 22 and the third valve 23 to allow the low-purity nitrogen to pass through the filter device 5 and remove the carbon dioxide and water from the low-purity nitrogen; when the upstream cannot supply low-purity nitrogen and air must be used as raw material, the operator or system closes the second valve 22 and the fourth valve 24, and opens the first valve 21 and the third valve 23 to force the air discharged from the compressor 1 to pass through the filter device 5 for purification before entering the cold box 4, ensuring that impurities are completely removed.

[0037] Overall, this embodiment achieves flexible selection of whether to perform purification treatment based on the quality of the raw gas by adding a switching valve on the outlet side of the compressor 1 and cooperating with the filter device 5. When using low-purity nitrogen, it further reduces system resistance and operating costs, and when using air, it can still ensure the purification effect. Thus, while ensuring the safe operation of the cold box 4, it further improves the energy efficiency and economy of the device.

[0038] It should be noted that the compressor 1 is connected to the cold box 4 through the third valve 23 and the filter device 5, or through the fourth valve 24, rather than being directly connected to the cold box 4.

[0039] Please see Figure 1 In an embodiment of this utility model, the cold box 4 includes a main heat exchanger 41 and a distillation column 42. The outlet end of the filter device 5 and the outlet end of the fourth valve 24 are connected in parallel and communicate with the main heat exchanger 41. The distillation column 42 is connected with the main heat exchanger 41. The main heat exchanger 41 is used to cool the incoming raw material gas. The distillation column 42 is used to distill the cooled raw material gas and discharge the distilled nitrogen gas from the top and the lean nitrogen liquid from the bottom.

[0040] In this embodiment, the cold box 4 is equipped with a main heat exchanger 41 and a distillation column 42, which are connected together to form a functional module that couples cooling and distillation. The outlet of the filter device 5 is connected in parallel with the outlet of the fourth valve 24 and then connected to the main heat exchanger 41. This allows raw materials supplied from different gas sources to be cooled to near their condensation point via the main heat exchanger 41, thus preparing for subsequent distillation separation. Furthermore, the distillation column 42 is connected to the main heat exchanger 41, enabling the distillation separation of the cooled raw materials. By utilizing the difference in boiling points between nitrogen and other components, the raw materials are separated within the distillation column 42. The distillation column 42 discharges high-purity nitrogen from the top as the product, while simultaneously discharging lean nitrogen liquid from the bottom to remove impurities. This completes the nitrogen purification process and maintains material balance and continuous operation within the column, improving the overall energy efficiency and operational reliability of the nitrogen generator.

[0041] It should be noted that lean nitrogen liquid refers to a liquid with a nitrogen content (mass ratio) lower than that of the feed gas. In distillation separation, the feed gas is a mixture with components having different volatility. By utilizing this difference in volatility, lighter components (low-boiling substances) in the liquid phase can be transferred to the gas phase, while heavier components (high-boiling substances) in the gas phase can be transferred to the liquid phase, thus achieving separation. The nitrogen content of the separated liquid phase is lower than that of the feed gas, hence the name lean nitrogen liquid. Under gravity, the lean nitrogen liquid collects at the bottom of the cavity within distillation column 42 and is then discharged.

[0042] As an optional implementation, the main heat exchanger 41 can be configured as a plate-fin heat exchanger or a coiled tube heat exchanger, both of which can achieve heat exchange. Preferably, the main heat exchanger 41 is configured as a plate-fin heat exchanger, thereby achieving efficient heat exchange over a wide temperature range from -180°C to room temperature, and its compact structure can reduce the volume of the cold box 4.

[0043] In addition, as an optional implementation, the distillation column 42 has a cavity with multiple layers of sieve plates or packing.

[0044] In this embodiment, the distillation column 42 constructs a multi-stage gas-liquid contact mass transfer structure within its cavity by setting multiple layers of sieve plates or packings distributed vertically at intervals. During the ascent of the raw gas, it comes into contact with the liquid phase on the sieve plates or packings multiple times and undergoes repeated heat and mass transfer, enabling efficient separation of components with different boiling points and improving the nitrogen purity to over 99.999%.

[0045] When the cavity contains multiple sieve plates, the distillation column is a sieve plate column (also known as a plate column). The multiple sieve plates are distributed vertically at intervals, and each sieve plate has multiple openings, allowing the feed gas to contact the liquid phase on the sieve plate and transfer heat and mass through the openings. When the cavity contains multiple packing layers, the distillation column is a packed column, and the multiple packing layers can also be distributed vertically at intervals. The design of multiple sieve plates or multiple packing layers distributed vertically at intervals extends the gas-liquid contact path, thereby improving separation efficiency and product yield, better adapting to trace impurities that may be present in the feed gas, and ensuring the long-term stable operation of distillation column 42.

[0046] Furthermore, a distributor can be installed on every certain number of sieve plates or packing layers. The distributor is used to redistribute the liquid in the cavity of the distillation column 42, thereby ensuring that the liquid on each sieve plate or packing layer is distributed as evenly as possible. Generally, 2 to 3 distributors can be installed in the entire distillation column 42. Of course, the actual number can be changed according to the needs and is not limited here.

[0047] Please see Figure 1 In an embodiment of this utility model, the cold box 4 further includes a condenser 43, which is connected to the top of the cavity of the distillation column 42 through a heat exchange pipeline and performs heat exchange. The condenser 43 is used to cool the nitrogen gas in the top of the cavity of the distillation column 42.

[0048] The condenser 43 is used to liquefy and cool the nitrogen gas in the top of the cavity of the distillation column 42. A portion of the nitrogen gas that is not liquefied is discharged through the top of the cavity of the distillation column 42, which is the nitrogen gas after distillation. The remaining liquefied liquid nitrogen flows back into the cavity of the distillation column 42 as reflux liquid to participate in the distillation.

[0049] In this embodiment, by adding a condenser 43 to the cold box 4 and connecting the condenser 43 to the top of the cavity of the distillation column 42 through a heat exchange pipeline for heat exchange, a cooling and reflux structure for nitrogen at the top of the column is constructed. The condenser 43 cools the nitrogen in the top of the cavity of the distillation column 42, causing some of the nitrogen to condense into liquid nitrogen and reflux back into the distillation column 42, providing the required reflux liquid for the distillation process, enhancing the separation effect of the distillation column 42, and improving the product purity.

[0050] The distillation column 42 has a liquid collection tray and a distributor at the top of its cavity. The liquid collection tray can catch the liquid nitrogen that is cooled back from the condenser 43, and the distributor can distribute the liquid nitrogen on the liquid collection tray to the sieve plate or packing below, thus achieving the above-mentioned distribution effect.

[0051] Additionally, it should be noted that the condenser 43 has a first chamber and a second chamber that are separated from each other. Heat exchange can occur between the first chamber and the second chamber, and the heat exchange pipeline is a circulation pipeline. Nitrogen gas located at the top of the cavity of the distillation column 42 reaches the first chamber of the condenser 43 through the circulation pipeline and exchanges heat with the second chamber to obtain cooled liquid nitrogen. The cooled liquid nitrogen flows back to the top of the cavity of the distillation column 42 through the circulation pipeline and is caught by the aforementioned liquid collection tray. In this way, the cooling and reflux of nitrogen gas can be achieved.

[0052] Please see Figure 1 In an embodiment of this utility model, a first opening is provided at the bottom of the distillation column 42, the first opening is connected to the bottom of the cavity, the first opening is connected to the condenser 43 through a first pipeline, and a throttling valve 44 is provided on the first pipeline; the lean nitrogen liquid located at the bottom of the cavity flows into the condenser 43 as a coolant through the first pipeline.

[0053] In this embodiment of the invention, a first opening communicating with the bottom of the cavity is provided at the bottom of the distillation column 42, and the first opening is connected to the condenser 43 through a first pipeline. A throttling valve 44 is installed on the first pipeline, thus establishing a pathway for the outlet and utilization of lean nitrogen liquid. Based on the Joule-Thomson effect, the temperature of the lean nitrogen liquid decreases due to the reduced pressure after passing through the throttling valve 44, allowing it to cool and flow into the condenser 43 as a coolant. The low-temperature characteristics of the lean nitrogen liquid are used to cool the nitrogen gas at the top of the column, achieving cascaded utilization of internal cooling capacity and avoiding additional consumption from external cooling sources. Furthermore, the throttling valve 44 allows for precise regulation of the flow rate and pressure of the lean nitrogen liquid, maintaining appropriate evaporation pressure and temperature when it enters the condenser 43. This ensures a stable and sufficient supply of cooling capacity to the condenser 43, while preventing excessive flow of lean nitrogen liquid from causing low bottom liquid levels or fluctuations in internal operating conditions, thus guaranteeing the coordinated and stable operation of the distillation column 42 and the condenser 43.

[0054] It should be noted that the lean nitrogen liquid is introduced into the second chamber of the condenser 43, so that the lean nitrogen liquid in the second chamber exchanges heat with the nitrogen in the first chamber, so that the nitrogen is cooled and partially liquefied, while the lean nitrogen liquid absorbs heat and evaporates into waste nitrogen.

[0055] As an alternative implementation, the temperature of the lean nitrogen solution after passing through the throttle valve 44 is 1 to 5°C lower than that of the nitrogen gas at the top of the chamber of the distillation column 42.

[0056] In this embodiment of the invention, by setting the temperature of the lean nitrogen liquid after passing through the throttling valve 44 to be 1 to 5°C lower than that of the nitrogen gas at the top of the distillation column 42, a reasonable and stable heat transfer temperature difference is formed in the condenser 43. This temperature difference range ensures that the condenser 43 can efficiently absorb the heat of the nitrogen gas at the top of the column, allowing the nitrogen gas to be fully condensed and refluxed, while avoiding the problem of frost formation on the surface of the condenser 43 or a decrease in heat transfer efficiency due to excessive temperature difference. In addition, the temperature difference control of 1 to 5°C makes the evaporation process of the lean nitrogen liquid in the condenser 43 more stable, and the temperature of the waste nitrogen gas after evaporation is moderate, which is conducive to the subsequent recovery of cold energy in the main heat exchanger 41. At the same time, this setting also reduces the risk of insufficient condensation load and insufficient reflux liquid volume due to excessively small temperature difference, which affects the distillation separation effect. Thus, it takes into account both condensation efficiency and system energy efficiency, and improves the overall performance and stability of the device.

[0057] Please see Figure 1 In an embodiment of this utility model, the top of the cavity of the distillation column 42 is also connected to the main heat exchanger 41. The distilled nitrogen gas discharged from the top of the cavity of the distillation column 42 is discharged as product gas after heat exchange through the main heat exchanger 41.

[0058] In this embodiment of the invention, the top of the cavity of the distillation column 42 is connected to the main heat exchanger 41, and the distilled nitrogen gas is discharged as product gas after heat exchange in the main heat exchanger 41, thereby realizing the recovery of cold energy and temperature regulation of the product nitrogen gas. Due to the cooling of the condenser 43, the high-purity nitrogen gas discharged from the top of the distillation column 42 is at a low temperature. If it is directly transported to downstream users as product gas, it will cause a large amount of cold energy waste and may lead to condensation in the pipeline or embrittlement of the materials. Therefore, by passing the distilled nitrogen gas into the main heat exchanger 41 to exchange heat with the feed gas, on the one hand, the distilled nitrogen gas is reheated to near room temperature, meeting the usage requirements of downstream users and facilitating safe transportation; on the other hand, it can supply some cold energy to the main heat exchanger 41, cooling the feed gas to near the condensation point, realizing the recovery of cold energy in the product gas, reducing the refrigeration load of the main heat exchanger 41, and thus reducing the consumption of liquid nitrogen replenishment and the overall energy consumption of the system.

[0059] Please see Figure 1 In this embodiment of the present invention, the condenser 43 is also connected to the main heat exchanger 41 and the filter device 5 in sequence through the second pipeline. The lean nitrogen liquid in the condenser 43 is evaporated into waste nitrogen gas, and after heat exchange through the main heat exchanger 41 via the second pipeline, it is introduced into the filter device 5 as regeneration gas.

[0060] In this embodiment, the condenser 43 is connected to the main heat exchanger 41 and the filter device 5 in sequence via a second pipeline. The lean nitrogen liquid evaporated in the condenser 43 becomes waste nitrogen gas, which then passes through the main heat exchanger 41 for heat exchange and the filter device 5 for regeneration, thus establishing a comprehensive utilization pathway for waste nitrogen gas. In the main heat exchanger 41, the waste nitrogen gas exchanges heat with the raw material gas or product gas, further recovering residual cold energy and improving the system's energy utilization rate. Furthermore, the waste nitrogen gas is used as regeneration gas in the filter device 5. Utilizing its low temperature, dryness, high nitrogen purity, and absence of carbon dioxide, the adsorbent in the filter device 5 is backflushed and regenerated. This achieves resource utilization of the waste gas while avoiding the increased equipment complexity and energy consumption caused by introducing an additional regeneration gas source. Simultaneously, the low-pressure regeneration gas improves the regeneration effect of the adsorbent, extends its service life, and reduces the maintenance cost and operating expenses of the device.

[0061] Since the third valve 23 opens and closes according to whether the raw gas contains carbon dioxide and water, waste nitrogen gas needs to be introduced into the filter device 5 as regeneration gas whenever any raw gas containing carbon dioxide and water is introduced into the filter device 5. Therefore, a reversing valve can be installed on the second pipeline between the main heat exchanger 41 and the filter device 5. When no raw gas containing carbon dioxide and water has been introduced into the filter device 5, the reversing valve is adjusted so that the regeneration gas is directly discharged into the air; when raw gas containing carbon dioxide and water has been introduced into the filter device 5, the reversing valve is adjusted so that the regeneration gas can be introduced into the filter device 5 to regenerate the filter device 5.

[0062] In an embodiment of this utility model, the top of the distillation column 42 is provided with a liquid nitrogen supply port that communicates with the cavity, and the liquid nitrogen supply port is provided with a switch.

[0063] In an embodiment of this utility model, a liquid nitrogen supply port connected to the cavity is opened at the top of the distillation column 42 and a switch is provided, so that liquid nitrogen is supplied to the cavity through the liquid nitrogen supply port as needed, so as to balance the heat loss of the entire nitrogen generating device due to heat exchange loss and heat leakage from the cold box 4. At the same time, the supplied liquid nitrogen can also be used as part of the reflux liquid of the distillation column 42 to improve the efficiency of the entire nitrogen generating device.

[0064] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A nitrogen generating device, characterized in that, include: compressor; A valve assembly, comprising a first valve and a second valve, wherein the outlet ends of the first valve and the second valve are connected in parallel and then connected to the inlet of the compressor; An air filter, wherein the inlet end of the first valve is connected in series with the air filter; A cold box, which is connected to the outlet of the compressor, is used to purify nitrogen.

2. The nitrogen generator as described in claim 1, characterized in that, The valve assembly further includes a third valve and a fourth valve, wherein the inlet end of the third valve and the inlet end of the fourth valve are connected in parallel and communicate with the outlet of the compressor; The nitrogen generator also includes a filter device. The inlet of the filter device is connected in series with the outlet of the third valve. The outlet of the filter device and the outlet of the fourth valve are connected in parallel and then connected to the cold box. The filter device is used to filter out carbon dioxide and water from the gas.

3. The nitrogen generator as described in claim 2, characterized in that, The cold box includes a main heat exchanger and a distillation column. The outlet end of the filter device and the outlet end of the fourth valve are connected in parallel and communicate with the main heat exchanger. The distillation column is connected with the main heat exchanger. The main heat exchanger is used to cool the incoming raw gas. The distillation column is used to distill the cooled raw gas and discharge the distilled nitrogen from the top and the lean nitrogen liquid from the bottom.

4. The nitrogen generator as described in claim 3, characterized in that, The distillation column has a cavity, and the cavity is equipped with multiple layers of sieve plates or packing.

5. The nitrogen generator as described in claim 4, characterized in that, The cold box also includes a condenser, which is connected to the top of the distillation column cavity via heat exchange pipelines for heat exchange. The condenser is used to cool the nitrogen gas in the top of the distillation column cavity.

6. The nitrogen generator as described in claim 5, characterized in that, The bottom of the distillation column is provided with a first opening, which is connected to the bottom of the cavity. The first opening is connected to the condenser through a first pipeline, and a throttling valve is provided on the first pipeline. The nitrogen-deficient liquid located at the bottom of the cavity flows into the condenser as a coolant through the first pipe.

7. The nitrogen generator as described in claim 6, characterized in that, The temperature of the lean nitrogen solution after passing through the throttling valve is 1 to 5°C lower than that of the nitrogen gas at the top of the distillation column.

8. The nitrogen generator as described in claim 6, characterized in that, The top of the cavity of the distillation column is also connected to the main heat exchanger. The distilled nitrogen gas discharged from the top of the cavity of the distillation column undergoes heat exchange in the main heat exchanger and is then discharged as product gas.

9. The nitrogen generator as described in claim 6, characterized in that, The condenser is also connected to the main heat exchanger and the filter device in sequence through a second pipeline. The lean nitrogen liquid in the condenser is evaporated into waste nitrogen gas, which is then exchanged with heat through the main heat exchanger via the second pipeline and then introduced into the filter device as regeneration gas.

10. The nitrogen generating apparatus according to any one of claims 5 to 9, characterized in that, The top of the distillation column is provided with a liquid nitrogen supply port that connects to the cavity, and the liquid nitrogen supply port is equipped with a switch.

Images