Optical fiber deuterium recycling system and method

Abstract

The present application relates to the technical field of deuterium-containing exhaust gas treatment, and particularly relates to a fiber deuterium gas recycling system and method, and the fiber deuterium gas recycling system at least comprises a nitrogen gas supplementing device, a deuterization cabinet, a vacuum system, a compression system, a purification and recovery system and a storage system. A purification system is further arranged between the purification and recovery system and the storage system. The present application is provided with the purification and recovery system, which removes water, dries and removes VOC from the deuterium-nitrogen mixed gas discharged from the deuterization cabinet, so that the deuterium-nitrogen mixed gas can be recycled. Meanwhile, the purification system is arranged, and the mixed gas is treated by the catalytic system, the purification equipment and the deuterium gas purification system in the purification system, so that the deuterium gas concentration can reach 99%. Meanwhile, the deuterium gas detector is arranged to adjust the concentration change in real time, so that the fiber processing requirements can be met.

Description

Technical Field

[0001] This invention relates to the field of deuterium-containing waste gas treatment technology, and in particular to a fiber optic deuterium gas recycling system and method. Background Technology

[0002] During the fiber drawing process, some disordered silicon-oxygen free radicals are generated. These free radicals readily react with hydrogen in the air to form silanol groups, which can easily cause fiber aging. Deuterium treatment is the final step in fiber manufacturing. Its mechanism is to combine deuterium with silicon-oxygen free radicals to form Si-OD bonds. The formation of Si-OD bonds prevents hydrogen from replacing the deuterium, allowing the fiber to withstand long-term corrosion in a hydrogen-containing environment.

[0003] Given the high cost of deuterium gas, it is often necessary to recover and reuse the deuterium-nitrogen mixture discharged from the deuterium treatment tank in actual production. Patent application CN213060215U discloses a deuterium gas recovery and treatment device for optical fiber fabrication, specifically including a deuterium gas treatment cabinet, a buffer tank, a drying and purification unit, a gas purification device, and a recovered gas storage tank. However, the above patent still has a problem: hydrogen gas is generated during deuterium gas treatment, and the deuterium-nitrogen mixture recovery and treatment does not consider removing the hydrogen gas generated during deuterium gas treatment to avoid its impact on attenuation at 1338nm in the optical fiber during reuse.

[0004] Patent CN1 17247237A discloses a fiber optic deuterium gas treatment and recycling system and method, specifically disclosing a deuterium-nitrogen gas supply device, a deuterium gas treatment tank, a vacuum device, a deuterium gas purification device, a recovery gas storage tank, a detection component, and a control component. Although it addresses the removal of hydrogen in the reaction, the reaction steps are cumbersome, and the concentration of deuterium in the recovered gas is not high. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to effectively recover and utilize energy and improve the utilization efficiency of deuterium in deuterium-containing waste gas.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] A fiber optic deuterium gas recycling system, comprising at least: a nitrogen replenishment device, a deuteration cabinet, a vacuum system, a compression system, a purification and recovery system, and a storage system, wherein the purification and recovery system includes a pre-cooling system and a VOC removal and drying system, wherein:

[0008] The nitrogen supply device is connected to the deuteration cabinet supply pneumatic valve via a mass flow controller and is used to supply nitrogen to the deuteration cabinet.

[0009] The vacuum system is connected to the gas collection pneumatic valve of the deuteration cabinet and is used to evacuate the deuteration cabinet into a vacuum.

[0010] The compression system is connected to the vacuum system and is used to compress the extracted gas;

[0011] The purification and recovery system is connected to the compression system and includes a pre-cooling system for removing free water and a VOC removal drying system for absorbing VOC gas and drying treatment, which are connected in sequence.

[0012] The storage system is connected to the compression system and is used to store purified and recovered gas. The storage system is connected to the deuteration cabinet through a pneumatic return valve.

[0013] The fiber optic deuterium gas recycling system also includes a purification system between the purification and recovery system and the storage system.

[0014] The vacuum system includes an oil-free vacuum pump and a low-pressure buffer tank; the compression system includes an oil-free compressor and a pressure buffer tank; the purification system includes a catalytic system, purification equipment, and a deuterium purification system; the storage system includes a concentration system and a storage tank, wherein the storage tank is a recovery storage tank and a product storage tank.

[0015] The nitrogen replenishment device is connected to the deuteration cabinet replenishment pneumatic valve via a mass flow controller to regulate the nitrogen replenishment amount. The deuteration cabinet collection pneumatic valve is connected to an oil-free vacuum pump to provide a deuterium-nitrogen mixture. A deuterium detector is also installed between the oil-free vacuum pump and the low-pressure buffer tank, which stores the deuterium-nitrogen mixture. The low-pressure buffer tank compresses the deuterium-nitrogen mixture into a pressure buffer tank via an oil-free compressor. The pressure buffer tank is connected to a pre-cooling system to remove free water. The pre-cooling system is connected to a VOC removal and drying system to remove VOCs and water. The VOC removal and drying system includes two adsorption cylinders that are used alternately. The adsorption cylinders include ZSM-5 molecular sieves or β molecular sieves. The VOC removal and drying system is connected to a concentration system. A deuterium detector is also installed between the concentration system and the storage tank, which stores a deuterium-nitrogen mixture with a deuterium concentration greater than 4.5%.

[0016] In addition to the VOC drying system, it is also connected to a catalytic system for the catalytic synthesis of heavy water. The catalytic system includes a catalyst, Pd or Pt. The catalytic system is connected to a purification device for degassing and electrolysis. The purification device is a heavy water electrolysis cell. The degassing temperature is 60℃~100℃. The electrolyte in the electrolysis is sodium carbonate, potassium carbonate, or sodium deuterium oxide. The purification device is connected to a deuterium purification system, which includes a deoxygenation catalyst and an adsorbent. The deoxygenation catalyst is palladium-plated activated alumina or palladium-carbon fiber catalyst. The adsorbent is activated alumina or silver-X molecular sieve. The deuterium purification system is connected to a concentration system. A deuterium detector is also installed between the concentration system and the storage tank. The storage tank is used to store gas with a deuterium concentration of not less than 99%.

[0017] A method for recycling deuterium gas in optical fibers, characterized by comprising the following steps:

[0018] S1, the deuteration process in the deuteration cabinet is complete, and the deuteration cabinet is evacuated;

[0019] S2, the deuterium-nitrogen mixture extracted by the vacuum system is compressed by an oil-free compressor and then transported to a pressure buffer tank for storage;

[0020] S3, the compressed deuterium-nitrogen mixture is pre-cooled by the pre-cooling system and then enters the VOC removal and drying system, and is purified by the concentration system;

[0021] S4, the concentrated deuterium-nitrogen mixture is stored in a recovery storage tank for reuse in deuteration.

[0022] S1 includes:

[0023] S1.1 Evacuate the deuteration cabinet to -25kPa to -20kPa;

[0024] S1.2 The deuterium-nitrogen mixture is transported to the buffer tank, and nitrogen is introduced until the pressure in the deuteration cabinet reaches 20 kPa to 25 kPa;

[0025] S1.3 Then, the deuteration cabinet is evacuated to -25 kPa to -20 kPa;

[0026] S1.4 Extract the deuterium-nitrogen mixture from the deuteration cabinet and transfer it to the buffer tank. Repeat this process 2-3 times until the deuterium concentration in the mixture measured by the deuterium detector at the vacuum pump outlet drops to 0. Then, stop the vacuum pump and close the gas collection pneumatic valve and the gas replenishment pneumatic valve.

[0027] S3 includes:

[0028] S3.1, the compressed deuterium-nitrogen mixture is pre-cooled by a pre-cooling system;

[0029] S3.2, enters the VOC removal and drying system to remove VOCs, deoxygenate, and dry;

[0030] S3.3 After purification by the concentration system, the deuterium concentration is detected by a deuterium detector. When the deuterium concentration is lower than 4.5%, the concentrated mixed gas is returned to the low-pressure buffer tank for continued circulation and concentration until the deuterium concentration in the gas after the concentration system reaches 4.5% or higher.

[0031] Includes the following steps:

[0032] S1, deuteration in the deuteration cabinet is complete, start the vacuum pump;

[0033] S2, the deuterium-nitrogen mixture extracted by the vacuum system is compressed by an oil-free compressor and then transported to a pressure buffer tank for storage;

[0034] S3, after being compressed, the deuterium-nitrogen mixture passes through a pre-cooling system to remove some of the free water, and then enters a VOC removal and drying system to remove VOC impurities and remove water from the mixture.

[0035] S4, after the mixed gas is catalyzed by the catalytic system, the gas produced by the purification equipment is purified by the deuterium purification system to remove oxygen, and then the gas is obtained by the deuterium detector with a deuterium concentration of not less than 99%.

[0036] S5, the concentrated gas is stored in the product storage tank and then supplied for deuteration.

[0037] S1 includes:

[0038] S1.1, Start the vacuum pump, open the gas collection valve and the gas supply valve;

[0039] S1.2, the nitrogen supply is adjusted by a mass flow controller;

[0040] S1.3, the amount of deuterium-nitrogen mixture extracted by the vacuum pump and the amount of nitrogen added are balanced, and the pressure of the deuteration cabinet is always maintained at ±100Pa;

[0041] S1.4 When the vacuum pump outlet analyzer detects that the deuterium concentration in the mixed gas has dropped to 0, the vacuum pump stops working, and the gas collection pneumatic valve and the gas replenishment pneumatic valve are closed.

[0042] Beneficial effects: This invention fully utilizes energy by recovering and recycling deuterium and deuterium-nitrogen mixtures from deuterium-containing waste gas, saving costs. Simultaneously, by setting up a purification and recovery system, the invention removes water, dries, and removes VOCs from the deuteration cabinet, enabling the recycling of the deuterium-nitrogen mixture. Furthermore, a purification system is included, which uses a catalytic system, purification equipment, and a deuterium purification system to treat the mixed gas, achieving a deuterium concentration of up to 99%. A deuterium detector is also installed to adjust the concentration changes in real time, ensuring it meets the requirements for fiber optic processing. Attached Figure Description

[0043] Figure 1 This is a flowchart of a method for recycling deuterium gas in optical fibers, as described in Example 1.

[0044] Figure 2 This is a schematic diagram of the structure of an optical fiber deuterium gas recycling system according to Example 1;

[0045] Figure 3 This is a flowchart of a method for recycling deuterium gas in optical fibers, as shown in Example 2.

[0046] Figure 4 This is a schematic diagram of the structure of an optical fiber deuterium gas recycling system in Example 2.

[0047] Among them, 01-receive air pneumatic valve, 02-replenish air pneumatic valve, 03-return supply pneumatic valve, and 04-supply air pneumatic valve. Detailed Implementation

[0048] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented under the premise of the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0049] Example 1

[0050] like Figure 1 , Figure 2 As shown, this embodiment provides an optical fiber deuterium recycling system, including a nitrogen replenishment device, a deuteration cabinet, a vacuum system, a compression system, a purification and recovery system, and a storage system.

[0051] The vacuum system includes an oil-free vacuum pump and a low-pressure buffer tank. After the optical fiber undergoes deuteration treatment in the deuteration cabinet, the vacuum pump evacuates the cabinet to -25 kPa, extracting the deuterium-nitrogen mixture and transferring it to the low-pressure buffer tank. Nitrogen is then introduced into the cabinet until the pressure reaches 20 kPa, and the cabinet is evacuated again to -25 kPa, extracting the deuterium-nitrogen mixture and transferring it to the buffer tank. This process is repeated three times. When the deuterium concentration in the mixture measured by the deuterium gas detector at the vacuum pump outlet drops to 0, the vacuum pump stops operating, and the O1 gas collection valve and O2 gas replenishment valve are closed. At the end of deuteration, approximately 1.5% deuterium-containing deuterium-nitrogen mixture is recovered.

[0052] The compression system includes an oil-free compressor and a pressure buffer tank.

[0053] The deuterium-nitrogen mixture extracted by the vacuum system is compressed by an oil-free compressor and then transported to a pressure buffer tank for storage.

[0054] The purification system includes a precooling system and a VOC removal and drying system. The compressed deuterium-nitrogen mixture is precooled by the precooling system, then enters the VOC removal and drying system to remove VOCs, oxygen, and dry the gas. Afterward, it is purified by a concentration system. The concentrated deuterium-nitrogen mixture is tested for deuterium concentration using a deuterium detector. When the deuterium concentration is below 4.5%, the concentrated mixture is returned to the low-pressure buffer tank after the vacuum pump for continued circulation and concentration until the deuterium concentration of the purified and concentrated gas reaches a product mixture of 4.5% or higher. The resulting mixture is then stored in a recovery storage tank for reuse in deuteration.

[0055] When the pressure in the recovery storage tank meets the requirements for reuse, the deuteration cabinet is provided with the necessary conditions for reuse. When the deuteration cabinet needs to be filled with mixed deuterium, the O3 return valve is opened to supply the deuterium-nitrogen mixture from the recovery storage tank to the deuteration cabinet. When the pressure in the recovery storage tank does not meet the requirements for reuse, the O3 return valve is closed, and the O4 fresh pure deuterium supply valve from the deuterium cylinder is opened to supply deuterium gas to the deuteration cabinet.

[0056] Example 2

[0057] like Figure 3 , Figure 4 As shown, this embodiment provides a fiber optic deuterium recycling system, including a nitrogen replenishment device, a deuteration cabinet, a vacuum system, a compression system, a purification and recovery system, a purification system, and a storage system.

[0058] The vacuum system consists of an oil-free vacuum pump and a low-pressure buffer tank. After the optical fiber is deuterated in the deuteration cabinet, a signal indicating the completion of deuteration is received, allowing for the recovery of the vacuum pump. The system then starts the vacuum pump, opens the 01 gas collection pneumatic valve and the 02 gas replenishment pneumatic valve, and adjusts the nitrogen replenishment rate via a mass flow controller to balance the amount of deuterium-nitrogen mixture extracted by the vacuum pump with the amount of nitrogen replenished, thus maintaining the pressure in the deuteration cabinet between ±100 Pa. When the deuterium concentration in the mixture measured by the deuterium gas detector at the vacuum pump outlet drops to 0, the vacuum pump stops operating, the 01 gas collection valve and the 02 gas replenishment valve close, and the collection process ends.

[0059] The compression system includes an oil-free compressor and a pressure buffer tank.

[0060] The deuterium-nitrogen mixture extracted by the vacuum system is compressed by an oil-free compressor and then transported to a pressure buffer tank for storage.

[0061] After compression, the deuterium-nitrogen mixture is pre-cooled to remove some free water, then enters a VOC removal and drying system to remove VOC impurities and water from the mixture. It then passes through a catalytic system to synthesize heavy water. The catalytic system includes a Pd or Pt catalyst. The catalytic system is connected to the heavy water electrolysis cell of the purification equipment, where degassing is performed at 60℃~100℃, followed by electrolysis using sodium deuterium oxide as the electrolyte. The purification equipment is connected to a deuterium purification system, which includes palladium-plated activated alumina, palladium-carbon fiber catalyst, activated alumina, and silver-X molecular sieves. The deuterium purification system is connected to a concentration system, which is also equipped with a deuterium detector between itself and a storage tank. The storage tank stores gas with a deuterium concentration of not less than 99%. The gas is then passed into a product storage tank for storage and reuse in deuteration.

[0062] When the purity and pressure of the product deuterium in the product storage tank meet the requirements for resupply, the deuteration tank is given the necessary conditions for resupply. When the deuteration tank needs to be filled with pure deuterium, the resupply valve is opened, supplying pure deuterium from the product storage tank into the deuteration tank. When the purity or pressure of the product in the product storage tank does not meet the requirements for resupply, the deuteration tank is given the necessary conditions for resupply. When the deuteration tank needs to be filled with pure deuterium, the resupply valve is closed, and the fresh pure deuterium supply valve from the deuterium cylinder is opened, supplying deuterium gas into the deuteration tank.

[0063] The above specific embodiments further illustrate the purpose, technical solution and beneficial effects of this application. It should be understood that the above are only specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of this application should be included within the scope of protection of this application.

Claims

1. A fiber optic deuterium gas recycling system, characterized in that, The fiber optic deuterium gas recycling system includes at least: a nitrogen gas replenishment device, a deuteration cabinet, a vacuum system, a compression system, a purification and recovery system, and a storage system. The purification and recovery system includes a pre-cooling system and a VOC removal and drying system. The nitrogen supply device is connected to the deuteration cabinet supply pneumatic valve via a mass flow controller and is used to supply nitrogen to the deuteration cabinet. The vacuum system is connected to the gas collection pneumatic valve of the deuteration cabinet and is used to evacuate the deuteration cabinet into a vacuum. The compression system is connected to the vacuum system and is used to compress the extracted gas; The purification and recovery system is connected to the compression system and includes a pre-cooling system for removing free water and a VOC removal drying system for absorbing VOC gas and drying treatment, which are connected in sequence. The storage system is connected to the compression system and is used to store purified and recovered gas. The storage system is connected to the deuteration cabinet through a return pneumatic valve. The fiber optic deuterium gas recycling system also includes a purification system between the purification and recovery system and the storage system. The vacuum system includes an oil-free vacuum pump and a low-pressure buffer tank; the compression system includes an oil-free compressor and a pressure buffer tank; the purification system includes a catalytic system, purification equipment, and a deuterium purification system; the storage system includes a concentration system and a storage tank, wherein the storage tank is a recovery storage tank and a product storage tank. In addition to the VOC drying system, it is also connected to a catalytic system for the catalytic synthesis of heavy water. The catalytic system includes a catalyst, Pd or Pt. The catalytic system is connected to a purification device for degassing and electrolysis. The purification device is a heavy water electrolysis cell. The degassing temperature is 60℃~100℃. The electrolyte in the electrolysis is sodium carbonate, potassium carbonate, or sodium deuterium oxide. The purification device is also connected to a deuterium purification system, which includes a deoxygenation catalyst and an adsorbent. The deoxygenation catalyst is palladium-plated activated alumina or palladium-carbon fiber catalyst. The adsorbent is activated alumina or silver-X molecular sieve. The deuterium purification system is also connected to a concentration system. A deuterium detector is installed between the concentration system and the storage tank. The storage tank is used to store gas with a deuterium concentration of not less than 99%. The nitrogen replenishment device is connected to the deuteration cabinet replenishment pneumatic valve via a mass flow controller to regulate the nitrogen replenishment amount. The deuteration cabinet collection pneumatic valve is connected to an oil-free vacuum pump to provide a deuterium-nitrogen mixture. A deuterium detector is also installed between the oil-free vacuum pump and the low-pressure buffer tank, which stores the deuterium-nitrogen mixture. The low-pressure buffer tank compresses the deuterium-nitrogen mixture into a pressure buffer tank via an oil-free compressor. The pressure buffer tank is connected to a pre-cooling system to remove free water. The pre-cooling system is connected to a VOC removal and drying system to remove VOCs and water. The VOC removal and drying system includes two adsorption cylinders that are used alternately. The adsorption cylinders include ZSM-5 molecular sieves or β molecular sieves. The VOC removal and drying system is connected to a concentration system. A deuterium detector is also installed between the concentration system and the storage tank, which stores a deuterium-nitrogen mixture with a deuterium concentration greater than 4.5%.

2. A method for recycling deuterium gas in optical fibers, implemented based on the optical fiber deuterium gas recycling system of claim 1, characterized in that, Includes the following steps: S1, the deuteration process in the deuteration cabinet is complete, and the deuteration cabinet is evacuated; S2, the deuterium-nitrogen mixture extracted by the vacuum system is compressed by an oil-free compressor and then transported to a pressure buffer tank for storage; S3, the compressed deuterium-nitrogen mixture is pre-cooled by the pre-cooling system and then enters the VOC removal and drying system, and is purified by the concentration system; S3 includes: S3.1, the compressed deuterium-nitrogen mixture is pre-cooled by a pre-cooling system; S3.2, enters the VOC removal and drying system to remove VOCs, deoxygenate, and dry; S3.3, after purification by the concentration system, the deuterium concentration is detected by a deuterium detector. When the deuterium concentration is lower than 4.5%, the concentrated mixed gas is returned to the low-pressure buffer tank for continued circulation and concentration until the deuterium concentration in the gas after the concentration system reaches more than 4.5%. S4, the concentrated deuterium-nitrogen mixture is stored in a recovery storage tank for reuse in deuteration.

3. The method for recycling deuterium gas in optical fibers according to claim 2, characterized in that, S1 includes: S1.1 Evacuate the deuteration cabinet to -25kPa to -20kPa; S1.2 The deuterium-nitrogen mixture is transported to the buffer tank, and nitrogen is introduced until the pressure in the deuteration cabinet reaches 20 kPa to 25 kPa; S1.3 Then, the deuteration cabinet is evacuated to -25 kPa to -20 kPa; S1.4 Extract the deuterium-nitrogen mixture from the deuteration cabinet and transfer it to the buffer tank. Repeat this process 2-3 times until the deuterium concentration in the mixture measured by the deuterium detector at the vacuum pump outlet drops to 0. Then, stop the vacuum pump and close the gas collection pneumatic valve and the gas replenishment pneumatic valve.

4. A method for recycling deuterium gas in optical fibers, implemented based on the optical fiber deuterium gas recycling system of claim 1, characterized in that, Includes the following steps: S1, deuteration in the deuteration cabinet is complete, start the vacuum pump; S2, the deuterium-nitrogen mixture extracted by the vacuum system is compressed by an oil-free compressor and then transported to a pressure buffer tank for storage; S3, after being compressed, the deuterium-nitrogen mixture passes through a pre-cooling system to remove some of the free water, and then enters a VOC removal and drying system to remove VOC impurities and remove water from the mixture. S4, after the mixed gas is catalyzed by the catalytic system, the gas produced by the purification equipment is purified by the deuterium purification system to remove oxygen, and then the gas is obtained by the deuterium detector with a deuterium concentration of not less than 99%. S5, the concentrated gas is stored in the product storage tank and then supplied for deuteration.

5. The method for recycling deuterium gas in optical fibers according to claim 4, characterized in that, S1 includes: S1.1, Start the vacuum pump, open the gas collection valve and the gas supply valve; S1.2, the nitrogen supply is adjusted by a mass flow controller; S1.3, the amount of deuterium-nitrogen mixture extracted by the vacuum pump and the amount of nitrogen added are balanced, and the pressure of the deuteration cabinet is always maintained at ±100Pa; S1.4 When the vacuum pump outlet analyzer detects that the deuterium concentration in the mixed gas has dropped to 0, the vacuum pump stops working, and the gas collection pneumatic valve and the gas replenishment pneumatic valve are closed.

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