Single-solvent nitrogen recovery system

Abstract

The utility model discloses a single-solvent nitrogen recovery system and relates to the technical field of nitrogen recovery. The device comprises a low-temperature liquid ring vacuum compressor, a gas-liquid separator, a condenser, an activated carbon adsorption column and a nitrogen buffer tank, the low-temperature liquid ring vacuum compressor is connected with the gas-liquid separator through a pipeline, the bottom of the gas-liquid separator is connected with the organic solvent circulating inlet through a pipeline, the low-temperature liquid ring vacuum compressor is connected with the organic solvent circulating outlet through a pipeline, and the bottom of the gas-liquid separator is connected with the low-temperature liquid ring vacuum compressor through a pipeline. According to the nitrogen recycling device, nitrogen in the industrial process can be recycled, recycling of the nitrogen is achieved, organic solvents can be recycled, and therefore environmental pollution is reduced; compared with direct discharge after use, the use cost of the solvent can be saved, and the economic benefit is obvious; the adsorption column is recycled, and the desorbed organic solvent can be recycled into a rectification system to be retreated and reused, so that control and use are convenient, and the use safety is good.

Description

Technical Field

[0001] This utility model belongs to the field of nitrogen recovery technology, and in particular relates to a single solvent nitrogen recovery system. Background Technology

[0002] Nitrogen is widely used in industrial production as a safe, readily available, and clean medium. It is used extensively for purging before plant start-up, ensuring safety during production, and guaranteeing product quality.

[0003] There are currently two main nitrogen production processes: (1) Cryogenic air separation nitrogen production, which involves liquefying compressed air and passing it into a fractionation tower. Then, by utilizing the different boiling points of oxygen and nitrogen, nitrogen with a purity of over 99.9% and oxygen-enriched gas with 35% oxygen + nitrogen are separated. This is generally suitable for large-scale air separation, and because the start-up time is over two hours, the start-up cost is high, and the requirement for continuous gas usage is very high. It is suitable for large-scale nitrogen users with high purity requirements and low fluctuations in continuous gas usage. (2) Pressure swing adsorption nitrogen production, also known as PSA, utilizes the different adsorption rates of nitrogen and oxygen by molecular sieves under different pressures to produce nitrogen. This is also the most suitable technology for small-scale nitrogen production, and the purity range of economical nitrogen production can be 99-99.9%.

[0004] Currently, in industrial production, nitrogen is mostly directly emitted after use. Due to the large volume and high cost of nitrogen, direct emission results in the loss of entrained organic solvents and environmental pollution. Developing a nitrogen recovery system could yield significant benefits with relatively small investment. Therefore, this project proposes a single-solvent nitrogen recovery process that can recover nitrogen from industrial processes, enabling its recycling, and also recover organic solvents, thereby reducing environmental pollution and achieving increased efficiency and revenue. Utility Model Content

[0005] This invention provides a single solvent nitrogen recovery system, which solves the above problems.

[0006] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0007] This utility model discloses a single solvent nitrogen recovery system, which includes a cryogenic liquid ring vacuum compressor, a gas-liquid separator, a condenser, an activated carbon adsorption column, and a nitrogen buffer tank.

[0008] The cryogenic liquid ring vacuum compressor is connected to the waste nitrogen collection pipeline and the fresh nitrogen inlet via a nitrogen recovery pipeline. The cryogenic liquid ring vacuum compressor is connected to the gas-liquid separator via a pipeline. The bottom of the gas-liquid separator is connected to the organic solvent circulation inlet via a pipeline. The cryogenic liquid ring vacuum compressor is connected to the organic solvent circulation outlet via a pipeline. The bottom of the gas-liquid separator is connected to the cryogenic liquid ring vacuum compressor via a pipeline.

[0009] The top of the gas-liquid separator is connected to the condenser via a pipeline, the condenser is connected to the activated carbon adsorption column via a pipeline, the activated carbon adsorption column is connected to the nitrogen buffer tank via a pipeline, the top of the nitrogen buffer tank is connected to the nitrogen-using equipment via a pipeline, and the bottom of the nitrogen buffer tank and the condenser are connected to the gas-liquid separator via pipelines.

[0010] Furthermore, a filter valve assembly and a cooler are installed on the pipeline connecting the bottom of the gas-liquid separator to the cryogenic liquid ring vacuum compressor.

[0011] Furthermore, the cooler and condenser are respectively equipped with coolant circulation pipelines connected to the coolant inlet and coolant outlet.

[0012] Furthermore, the gas-liquid separator is equipped with a first pressure transmitter, a first safety valve pressure relief port, a first field pressure gauge, a field level gauge, and a level transmitter. A first wire mesh demister is installed at the upper part of the gas-liquid separator where it is connected to the condenser.

[0013] Furthermore, the field level gauge and level transmitter are connected in parallel on the side of the gas-liquid separator, and the level transmitter is connected to a water pump through a pipeline. The water pump is connected to the solvent extraction valve group and the organic solvent replenishment valve group at the organic solvent circulation inlet through pipelines respectively. The solvent extraction valve group is also connected to the side of the gas-liquid separator and the organic solvent circulation outlet.

[0014] Furthermore, the activated carbon adsorption column is provided in two sets, and the top of the activated carbon adsorption column is respectively connected to a saturated steam pipeline with a steam regulating valve connected to the saturated steam inlet. A second field pressure gauge and a second pressure transmitter are installed on the main pipeline of the saturated steam pipeline.

[0015] Furthermore, the bottom of the activated carbon adsorption column is equipped with an eluent discharge and recovery treatment pipe with a control valve.

[0016] Furthermore, the nitrogen buffer tank is equipped with a third field pressure gauge, a third pressure transmitter, and a second safety valve pressure relief port. A combustible gas detector is installed on the pipeline connecting the nitrogen buffer tank and the condenser, and the condenser is equipped with a second wire mesh demister connected to the combustible gas detector via a pipeline.

[0017] Furthermore, a nitrogen recovery output valve is installed on the pipeline between the nitrogen buffer tank and the nitrogen-using equipment, and a nitrogen recovery reflux valve is installed on the pipeline between the cryogenic liquid ring vacuum compressor and the top of the nitrogen buffer tank.

[0018] Furthermore, the recovered nitrogen output valve is connected via pipeline to the fresh nitrogen replenishment valve at the fresh nitrogen inlet, the oxygen analyzer on the pipeline between the vacuum compressor and the fresh nitrogen inlet, and the recovered nitrogen reflux valve.

[0019] The present invention has the following advantages over the prior art:

[0020] (1) Achieve nitrogen recycling: It can recover nitrogen from industrial processes and realize the recycling of nitrogen. It can also recover organic solvents, thereby reducing environmental pollution;

[0021] (2) Significant economic benefits: After this nitrogen recovery system is applied to industrial production, compared with the original method of directly discharging nitrogen after use, this process will significantly reduce the cost of nitrogen use and create greater benefits; if it is not recycled and directly discharged, fresh nitrogen needs to be continuously prepared for the process; if it can be recycled and reused, the cost of nitrogen recycling is much less than the cost of preparing new nitrogen, and the long-term economic benefits are obvious; in addition, this device can also separate some solvents mixed in waste nitrogen and obtain them for recycling and reuse. Through the deep purification process of condensation + activated carbon adsorption, the organic solvent content in the recovered nitrogen can be reduced to about 40mg per cubic meter. Compared with direct discharge after use, it can save the cost of solvent use, and the economic benefits are obvious.

[0022] (3) It can reduce the organic solvent content in the recovered nitrogen: The added activated carbon adsorption device, i.e., the activated carbon adsorption column, can be used for the deep treatment of waste gas with high treatment degree and stable effect; the adsorption device adopts a one-in-one standby working mode. After the organic solvent in the recovered nitrogen is further adsorbed by the activated carbon, the nitrogen enters the nitrogen buffer tank for standby, realizing the process cycle; the activated carbon adsorption device, i.e., the activated carbon adsorption column, is regenerated by steam desorption after adsorption saturation. The adsorption column is used in a cycle, and the desorbed organic solvent can be recovered and entered into the distillation system for further treatment and reuse;

[0023] (4) Easy to control and use: With the cooperation of water pump, level transmitter and field level gauge, the liquid level in the gas-liquid separator is automatically controlled to ensure the continuous and stable supply of working fluid of the low temperature liquid ring vacuum compressor, so as to ensure the stable operation of the system; the collected organic solvent is automatically discharged to the solvent recovery system for reuse according to the liquid level in the gas-liquid separator.

[0024] (5) Safety in use: The system is also equipped with components such as pressure transmitter, level transmitter, and pneumatic regulating valve to improve the level of automation control of the system. The device is centrally displayed and controlled to realize unmanned and stable operation of the system. An oxygen analyzer with online oxygen content detection is set up to detect the oxygen content in the recovered nitrogen in real time to ensure the safe and stable operation of the system. If the oxygen content in the recovered nitrogen exceeds the standard, the system can replenish qualified nitrogen in time to ensure that the oxygen content in the recovered nitrogen is within a reasonable and safe range.

[0025] Of course, any product implementing this utility model does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments 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 these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a single solvent nitrogen recovery system according to the present invention;

[0028] The attached diagram lists the components represented by each number as follows:

[0029] 1- Cryogenic liquid ring vacuum compressor; 11- Waste nitrogen collection pipeline; 12- Fresh nitrogen inlet; 121- Fresh nitrogen replenishment valve; 122- Oxygen analyzer; 13- Saturated steam inlet; 14- Organic solvent circulation outlet; 15- Organic solvent circulation inlet; 16- Organic solvent replenishment valve assembly; 17- Filter valve assembly; 2- Gas-liquid separator; 21- First wire mesh demister; 22- First field pressure gauge; 23- First safety valve pressure relief port; 24- First pressure transmitter; 25- Field level gauge; 26- Level transmitter; 27- Solvent outlet valve Group, 28-Water pump, 3-Condenser, 31-Second wire mesh demister, 4-Activated carbon adsorption column, 41-Steam regulating valve, 42-Second field pressure gauge, 43-Second pressure transmitter, 44-Desorption liquid discharge and recovery treatment pipe, 5-Nitrogen buffer tank, 51-Third field pressure gauge, 52-Third pressure transmitter, 53-Second safety valve pressure relief port, 54-Nitrogen usage equipment, 55-Recovered nitrogen output valve, 56-Combustible gas detector, 6-Cooler, 61-Coolant inlet, 62-Coolant outlet, 63-Recovered nitrogen reflux valve. Detailed Implementation

[0030] 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 skilled in the art without creative effort are within the protection scope of the present utility model.

[0031] In the description of this utility model, it should be understood that the terms "entrance", "bottom", "exit", "top", "parallel", etc., which indicate orientation or positional relationship, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0032] Please see Figure 1 As shown, this utility model discloses a single solvent nitrogen recovery system for the recovery and recycling of high-purity nitrogen from a single solvent, comprising a cryogenic liquid ring vacuum compressor 1, a gas-liquid separator 2, a condenser 3, an activated carbon adsorption column 4, and a nitrogen buffer tank 5.

[0033] The cryogenic liquid ring vacuum compressor 1 is connected to the waste nitrogen collection pipeline 11 and the fresh nitrogen inlet 12 via a nitrogen recovery pipeline. The cryogenic liquid ring vacuum compressor 1 is connected to the gas-liquid separator 2 via a pipeline. The bottom of the gas-liquid separator 2 is connected to the organic solvent circulation inlet 15 via a pipeline. The cryogenic liquid ring vacuum compressor 1 is connected to the organic solvent circulation outlet 14 via a pipeline. The bottom of the gas-liquid separator 2 is connected to the cryogenic liquid ring vacuum compressor 1 via a pipeline. If the nitrogen system is protected by acetone, acetone is used for the organic solvent liquid circulation. If the nitrogen system is protected by ethanol, ethanol is used for the organic solvent liquid circulation.

[0034] The top of the gas-liquid separator 2 is connected to the condenser 3 via a pipeline. The condenser 3 is connected to the activated carbon adsorption column 4 via a pipeline. The activated carbon adsorption column 4 is connected to the nitrogen buffer tank 5 via a pipeline. The top of the nitrogen buffer tank 5 is connected to the nitrogen-using equipment 54 via a pipeline. The bottom of the nitrogen buffer tank 5 and the condenser 3 are connected to the gas-liquid separator 2 via pipelines.

[0035] Specific flow direction such as Figure 1 As shown, the process flow is as follows: nitrogen and other process gases in the device → cryogenic liquid ring vacuum compressor → gas-liquid separator (saturated steam liquefaction and nitrogen separation) → nitrogen is further separated into other process gases by condensation → activated carbon adsorption → gas storage tank → returned to the device as a gas source for recycling.

[0036] The gas-liquid separator 2 is connected to the cryogenic liquid ring vacuum compressor 1 via a pipeline with a filter valve group 17 and a cooler 6.

[0037] Cooler 6 and condenser 3 are respectively equipped with coolant circulation pipelines connected to coolant inlet 61 and coolant outlet 62.

[0038] The gas-liquid separator 2 is equipped with a first pressure transmitter 24, a first safety valve pressure relief port 23, a first field pressure gauge 22, a field level gauge 25, and a level transmitter 26. A first wire mesh demister 21 is installed at the position where the gas-liquid separator 2 is connected to the condenser 3.

[0039] The on-site level gauge 25 and level transmitter 26 are connected in parallel on the side of the gas-liquid separator 2. The level transmitter 26 is connected to the water pump 28 through a pipeline. The water pump 28 is connected to the solvent extraction valve group 27 and the organic solvent replenishment valve group 16 at the organic solvent circulation inlet 15 through pipelines. The solvent extraction valve group 27 is also connected to the side of the gas-liquid separator 2 and the organic solvent circulation outlet 14.

[0040] The activated carbon adsorption column 4 is provided in two sets. The top of the activated carbon adsorption column 4 is connected to a saturated steam pipeline with a steam regulating valve 41 connected to the saturated steam inlet 13. A second field pressure gauge 42 and a second pressure transmitter 43 are installed on the main pipeline of the saturated steam pipeline.

[0041] The bottom of the activated carbon adsorption column 4 is equipped with an eluent discharge and recovery treatment pipe 44 with a control valve.

[0042] The nitrogen buffer tank 5 is equipped with a third field pressure gauge 51, a third pressure transmitter 52, and a second safety valve pressure relief port 53. A combustible gas detector 56 is installed on the pipeline connecting the nitrogen buffer tank 5 and the condenser 3, and a second wire mesh demister 31 is installed on the condenser 3 and connected to the combustible gas detector 56 through a pipeline.

[0043] A nitrogen recovery output valve 55 is installed on the pipeline between the nitrogen buffer tank 5 and the nitrogen use equipment 54, and a nitrogen recovery reflux valve 63 is installed between the cryogenic liquid ring vacuum compressor 1 and the top of the nitrogen buffer tank 5 via a pipeline.

[0044] The recovered nitrogen output valve 55 is connected to the fresh nitrogen replenishment valve 121 at the fresh nitrogen inlet 12, the oxygen analyzer 122 on the pipeline between the vacuum compressor 1 and the fresh nitrogen inlet 12, and the recovered nitrogen return valve 63 via a pipeline.

[0045] like Figure 1As shown, the cryogenic liquid ring vacuum compressor 1 of this system is connected to the nitrogen outlet via a nitrogen recovery pipeline. It requires the configuration of a waste nitrogen collection pipeline, namely, a fresh nitrogen replenishment valve 121, a recovered nitrogen reflux valve 63, and the relevant positions of an oxygen analyzer 122. After collection, the waste nitrogen enters the core equipment of this system, the cryogenic liquid ring vacuum compressor 1. This liquid ring vacuum compressor 1 can mix and draw in gas and liquid. Existing high-pressure liquid ring compressors can be used, which is existing technology; its specific principles will not be elaborated in this technical solution. The organic solvent liquid carried in the gas drawn into the cryogenic liquid ring vacuum compressor 1 will not adversely affect the normal operation of the compressor. The vacuum liquid ring vacuum compressor exhibits minimal temperature rise and low exhaust temperature during suction and compression, eliminating the need for a complex gas cooling system. Its simple structure, with only one rotating part and no metal-to-metal contact, results in fewer malfunctions and easy maintenance, making it suitable for handling flammable and explosive gases. It utilizes recycled organic solvents as the circulating working medium. Since the temperature of this medium rises during use, a cooler (6) is installed. The cooler requires a cryogenic medium temperature between -5°C and -10°C to ensure the working fluid temperature after heat exchange remains within the normal operating range of the cryogenic vacuum compressor. Typically, the working fluid temperature is controlled within the range of 5-10°C to maintain the compressor's optimal operating condition. The cryogenic liquid ring vacuum compressor (1) has an inlet ultimate vacuum of -0.097 MPa, a maximum exhaust pressure exceeding 0.3 MPa, and is made of 316L stainless steel.

[0046] The recovered nitrogen gas is pressurized by the cryogenic liquid ring vacuum compressor 1 and then enters a gas-liquid separator 2. In this gas-liquid separator 2, the gas and liquid are initially separated. A cyclone wire mesh demister, namely the first wire mesh demister 21, is installed at the outlet of the gas-liquid separator 2 to prevent small droplets from flowing out with the gas flow. This gas-liquid separator 2 serves as a solvent recovery tank and also as a liquid supply tank for the working fluid of the cryogenic liquid ring vacuum compressor 1.

[0047] After initial separation, the waste nitrogen gas enters the system condenser, namely condenser 3. Condenser 3 adopts a high-efficiency shell and tube mixer. The low temperature medium of -5 degrees to -10 degrees Celsius in condenser 3 cools down the waste nitrogen gas and the solvent in it. The organic solvent in the waste nitrogen gas condenses and precipitates out at low temperature and separates from the nitrogen gas. A cyclone wire mesh demister, namely the second wire mesh demister 31, is installed at the gas outlet of condenser 3. This process can remove most of the organic solvent.

[0048] To further reduce the organic solvent content in the recovered nitrogen, an additional activated carbon adsorption unit, namely activated carbon adsorption column 4, is added. Activated carbon adsorption is widely used for the deep treatment of waste gas. Activated carbon is made by activating carbon-containing materials such as wood, coal, and fruit shells under high-temperature and oxygen-deficient conditions. It has a huge specific surface area (500-1700 m²). 2 / g). Granular carbon is used for filtration and adsorption here, with the main advantages of high treatment efficiency and stable performance. The adsorption unit operates in a one-in-one-out-of-service mode. After the organic solvent in the recovered nitrogen is further adsorbed by the activated carbon, the nitrogen enters the nitrogen buffer tank 5 for standby, realizing process recycling. The activated carbon adsorption unit, i.e., the activated carbon adsorption column 4, is regenerated by steam desorption after adsorption saturation. The adsorption column is recycled, and the desorbed organic solvent can be recovered and further processed in the distillation system for reuse.

[0049] This system also includes a liquid level detection and control system for the gas-liquid separator. By setting the liquid level, and with the cooperation of the water pump 28, the liquid level transmitter 26, and the field liquid level gauge 25, the system automatically controls the liquid level in the gas-liquid separator 2, ensuring a continuous and stable supply of working fluid to the cryogenic liquid ring vacuum compressor 1, thereby guaranteeing the stable operation of the system. The collected organic solvent is automatically discharged to the solvent recovery system for reuse based on the liquid level in the gas-liquid separator.

[0050] This system is also equipped with components such as pressure transmitters, level transmitters, and pneumatic control valves to improve the level of automation control. The devices are centrally displayed and controlled, enabling unmanned and stable operation of the system. An oxygen analyzer 112 is installed to detect the oxygen content in the recovered nitrogen in real time, ensuring the safe and stable operation of the system. If the oxygen content in the recovered nitrogen exceeds the standard, the system can promptly replenish qualified nitrogen to ensure that the oxygen content in the recovered nitrogen is within a reasonable and safe range.

[0051] A combustible gas online detection device, namely combustible gas detector 56, is set up to detect the content of combustible gas in the gas after activated carbon adsorption treatment in real time, ensuring that the organic solvent in the system is effectively recovered; the system is equipped with safety valves, namely the first safety valve pressure relief port 23 and the second safety valve pressure relief port 53, on the buffer tank to ensure that the system does not operate under overpressure.

[0052] After this nitrogen recovery system is applied to industrial production, compared to the previous method of directly discharging nitrogen after use, this process significantly reduces the cost of nitrogen use and creates greater benefits. Field verification shows that the production cost of 1 cubic meter of nitrogen is approximately 0.45 yuan. If it is not recycled and directly discharged, fresh nitrogen needs to be continuously produced for the process. However, if it can be recycled and reused, the cost of nitrogen recycling is far less than the cost of producing new nitrogen; the cost of nitrogen recovery is about 30% of the cost of nitrogen production, resulting in significant long-term economic benefits. Simultaneously, this device can also separate some solvents mixed in waste nitrogen for recycling and reuse. Through a deep purification process of condensation and activated carbon adsorption, the organic solvent content in the recovered nitrogen can be reduced to no more than 40 mg per cubic meter. Compared to direct discharge after use, this saves on solvent usage costs, resulting in significant economic benefits.

[0053] The preferred embodiments of this utility model disclosed above are merely illustrative of the present utility model. These preferred embodiments do not exhaustively describe all details, nor do they limit the utility model to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of this utility model, thereby enabling those skilled in the art to better understand and utilize it. This utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A single solvent nitrogen recovery system, characterized in that, It includes a cryogenic liquid ring vacuum compressor (1), a gas-liquid separator (2), a condenser (3), an activated carbon adsorption column (4), and a nitrogen buffer tank (5); The cryogenic liquid ring vacuum compressor (1) is connected to the waste nitrogen collection pipeline (11) and the fresh nitrogen inlet (12) through the nitrogen recovery pipeline. The cryogenic liquid ring vacuum compressor (1) is connected to the gas-liquid separator (2) through the pipeline. The bottom of the gas-liquid separator (2) is connected to the organic solvent circulation inlet (15) through the pipeline. The cryogenic liquid ring vacuum compressor (1) is connected to the organic solvent circulation outlet (14) through the pipeline. The bottom of the gas-liquid separator (2) is connected to the cryogenic liquid ring vacuum compressor (1) through the pipeline. The top of the gas-liquid separator (2) is connected to the condenser (3) via a pipeline. The condenser (3) is connected to the activated carbon adsorption column (4) via a pipeline. The activated carbon adsorption column (4) is connected to the nitrogen buffer tank (5) via a pipeline. The top of the nitrogen buffer tank (5) is connected to the nitrogen-using equipment (54) via a pipeline. The bottom of the nitrogen buffer tank (5) and the condenser (3) are connected to the gas-liquid separator (2) via pipelines.

2. A single solvent nitrogen recovery system according to claim 1, wherein, The gas-liquid separator (2) is connected to the low-temperature liquid ring vacuum compressor (1) by a filter valve group (17) and a cooler (6) on the pipeline.

3. A single solvent nitrogen recovery system according to claim 2, wherein, The cooler (6) and condenser (3) are respectively equipped with coolant circulation pipelines connected to the coolant inlet (61) and coolant outlet (62).

4. A single solvent nitrogen recovery system according to claim 1, wherein, The gas-liquid separator (2) is equipped with a first pressure transmitter (24), a first safety valve pressure relief port (23), a first field pressure gauge (22), a field level gauge (25), and a level transmitter (26). A first wire mesh demister (21) is installed at the position where the gas-liquid separator (2) is connected to the condenser (3).

5. A single solvent nitrogen recovery system according to claim 4, wherein, The field level gauge (25) and level transmitter (26) are connected in parallel on the side of the gas-liquid separator (2), and the level transmitter (26) is connected to the water pump (28) through a pipeline. The water pump (28) is connected to the solvent extraction valve group (27) and the organic solvent replenishment valve group (16) at the organic solvent circulation inlet (15) through pipelines respectively. The solvent extraction valve group (27) is also connected to the side of the gas-liquid separator (2) and the organic solvent circulation outlet (14).

6. A single solvent nitrogen recovery system according to claim 1, wherein, The activated carbon adsorption column (4) is provided in two sets. The top of the activated carbon adsorption column (4) is connected to a saturated steam pipeline with a steam regulating valve (41) connected to the saturated steam inlet (13). A second field pressure gauge (42) and a second pressure transmitter (43) are installed on the main pipeline of the saturated steam pipeline.

7. A single solvent nitrogen recovery system according to claim 6, wherein, The bottom of the activated carbon adsorption column (4) is provided with an eluent discharge and recovery treatment pipe (44) with a control valve.

8. A single solvent nitrogen recovery system according to claim 1, wherein, The nitrogen buffer tank (5) is equipped with a third field pressure gauge (51), a third pressure transmitter (52) and a second safety valve pressure relief port (53). A combustible gas detector (56) is installed on the pipeline connecting the nitrogen buffer tank (5) and the condenser (3). The condenser (3) is equipped with a second wire mesh demister (31) connected to the combustible gas detector (56) through a pipeline.

9. A single solvent nitrogen recovery system according to claim 1, wherein, A nitrogen recovery output valve (55) is installed on the pipeline between the nitrogen buffer tank (5) and the nitrogen use equipment (54), and a nitrogen recovery reflux valve (63) is installed on the pipeline between the cryogenic liquid ring vacuum compressor (1) and the top of the nitrogen buffer tank (5).

10. A single solvent nitrogen recovery system according to claim 9, wherein, The recovered nitrogen output valve (55) is connected via pipeline to the fresh nitrogen replenishment valve (121) at the fresh nitrogen inlet (12), the oxygen analyzer (122) on the pipeline between the vacuum compressor (1) and the fresh nitrogen inlet (12), and the recovered nitrogen return valve (63).

Images