Optical fiber deuterium gas recycling system and method

Abstract

The invention relates to the technical field of deuterium-containing waste gas treatment, in particular to an optical fiber deuterium gas recycling system and method.The optical fiber deuterium gas recycling system at least comprises a nitrogen supplementing device, a deuterization cabinet, a vacuum system, a compression system, a purification and recovery system and a storage system. Wherein a purification system is further arranged between the purification and recovery system and the storage system. The deuterium-nitrogen mixed gas discharged from the deuterization cabinet is subjected to water removal, drying and VOC removal through the purification and recovery system, so that the deuterium-nitrogen mixed gas is recycled, meanwhile, the purification system is further arranged, the mixed gas is treated through the catalysis system, the purification equipment and the deuterium gas purification system in the purification system, the deuterium gas concentration can reach 99%, and the deuterium gas concentration can reach 99%. Meanwhile, a deuterium gas detector is arranged to adjust the concentration change in real time, so that the optical fiber processing requirement is met.

Description

Technical Field

[0001] The present invention relates to the technical field of deuterium-containing waste gas treatment, and in particular to an optical fiber deuterium gas recycling system and method. Background Art

[0002] During the drawing process of optical fiber, some disordered silicon oxygen free radicals will be generated. The silicon oxygen free radicals are easy to react with hydrogen in the air to form silanol, which is easy to cause the optical fiber to age. Deuterium treatment of optical fiber is the last step in optical fiber manufacturing. Its mechanism of action is to combine deuterium with silicon oxygen free radicals to form Si-OD bonds. The generation of Si-OD bonds prevents hydrogen from replacing the position of deuterium, allowing the optical fiber to withstand the erosion of hydrogen-containing environments for a long time.

[0003] Considering the high cost of using deuterium gas, it is often necessary to recycle the deuterium-nitrogen mixed gas discharged from the deuterium gas treatment tank in actual production. Patent application number is CN213060215U, which discloses a deuterium gas recovery and processing device for optical fiber preparation, and specifically discloses a deuterium gas treatment cabinet, a buffer tank, a drying and purification unit, a gas purification device, and a recovered gas storage tank. However, there are still problems with the above patent. Hydrogen will be generated during the deuterium gas treatment. When the deuterium-nitrogen mixed gas is recovered and processed, it is not considered to remove the hydrogen generated during the deuterium gas treatment to avoid the influence on the attenuation of the optical fiber at 1338nm when it is reused.

[0004] Patent CN1 17247237A discloses a fiber optic deuterium gas processing and recycling system and method, specifically disclosing a deuterium nitrogen gas supply device, a deuterium gas processing tank, a vacuum pumping device, a deuterium gas purification device, a recovery gas storage tank, a detection component and a control component. Although the system is aimed at removing hydrogen during 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 the present invention is to effectively recycle energy and improve the utilization efficiency of deuterium in deuterium-containing waste gas.

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

[0007] An optical fiber deuterium gas recycling system, the optical fiber deuterium gas recycling system at least comprises: a nitrogen gas replenishing device, a deuteration cabinet, a vacuum system, a compression system, a purification and recovery system, and a storage system. The purification and recovery system comprises a precooling 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 provide nitrogen to the deuteration cabinet;

[0009] The vacuum system is connected to the deuteration cabinet air collecting pneumatic valve 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, which includes a precooling system for removing free water and a VOC removal and drying system for absorbing VOC gas and performing drying treatment, which are connected in sequence;

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

[0013] The optical fiber deuterium gas recycling system is also provided with a purification system between the purification 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 gas purification system; the storage system includes a concentration system and storage tanks, and the storage tanks are recovery storage tanks and product storage tanks.

[0015] The nitrogen replenishing device is connected to the deuteration cabinet replenishing pneumatic valve by adjusting the nitrogen replenishing amount through the mass flow controller; the deuteration cabinet air collecting pneumatic valve is connected to the oil-free vacuum pump for providing deuterium-nitrogen mixed gas; a deuterium gas detector is also arranged between the oil-free vacuum pump and the low-pressure buffer tank, and the low-pressure buffer tank is used to store the deuterium-nitrogen mixed gas; the low-pressure buffer tank compresses the deuterium-nitrogen mixed gas into the pressure buffer tank through the oil-free compressor; the pressure buffer tank is connected to the precooling system for removing free water; the precooling system is connected to the VOC removal drying system for removing VOC gas and water, and the VOC removal drying system includes two adsorption cylinders, which are used alternately, and the adsorption cylinders include ZSM-5 molecular sieve or β molecular sieve; the VOC removal drying system is connected to the concentration system, and a deuterium gas detector is also arranged between the concentration system and the storage tank, and the storage tank is used to store the deuterium-nitrogen mixed gas with a deuterium concentration greater than 4.5%.

[0016] The VOC removal drying system is also connected to a catalytic system for catalytic synthesis of heavy water, wherein the catalytic system includes a catalyst Pd or Pt; the catalytic system is connected to a purification device, wherein the purification device is used for degassing electrolysis, wherein the purification device is a heavy water electrolysis cell, wherein the temperature required for degassing is 60° C. to 100° C., wherein the electrolyte in the electrolysis is sodium carbonate, potassium carbonate or sodium deuteride, and the purification device is connected to a deuterium gas purification system, wherein the deuterium gas purification system includes a deoxidation catalyst and an adsorbent, wherein the deoxidation catalyst is an activated alumina plated with palladium or a palladium carbon fiber catalyst, and the adsorbent is an activated alumina or a silver-X molecular sieve; the deuterium gas purification system is connected to a concentration system, wherein a deuterium gas detector is further provided between the concentration system and the storage tank, and the storage tank is used to store gas having a deuterium gas concentration of not less than 99%.

[0017] An optical fiber deuterium gas recycling method, characterized in that it comprises the following steps:

[0018] S1, the deuteration of the deuteration cabinet is completed, and the deuteration cabinet is evacuated;

[0019] S2, the deuterium-nitrogen mixed gas extracted from 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 mixed gas is precooled by the precooling system, then enters the VOC removal drying system, and is purified by the concentration system;

[0021] S4, the concentrated deuterium-nitrogen mixed gas is stored in a recovery storage tank and is returned to deuteration.

[0022] The S1 includes:

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

[0024] S1.2 Deuterium-nitrogen mixed gas is transported to the buffer tank, and nitrogen is introduced until the pressure of the deuteration cabinet reaches 20kPa~25kPa;

[0025] S1.3 Then evacuate the deuterated cabinet to -25kPa~-20kPa;

[0026] S1.4 Draw out the deuterium-nitrogen mixed gas in the deuteration cabinet and transport it to the buffer tank. Repeat this process 2 to 3 times until the deuterium gas detector at the vacuum pump outlet measures that the deuterium gas concentration in the mixed gas drops to 0. Then the vacuum pump stops working and the air collection pneumatic valve and air supply pneumatic valve are closed.

[0027] The S3 includes:

[0028] S3.1, the compressed deuterium-nitrogen mixture is precooled by a precooling system;

[0029] S3.2, enter the VOC removal and drying system to remove VOC, deoxidize and dry;

[0030] S3.3, after being purified by the concentration system, the deuterium gas concentration is detected by a deuterium gas detector. When the deuterium gas concentration is lower than 4.5%, the concentrated mixed gas returns to the low-pressure buffer tank and continues to circulate and concentrate until the deuterium gas concentration in the gas after the concentration system reaches more than 4.5%.

[0031] The steps include:

[0032] S1, the deuteration in the deuteration cabinet is completed and the vacuum pump is started;

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

[0034] S3, after the compressed deuterium nitrogen mixed gas passes through a pre-cooling system to remove a portion of free water, it enters a VOC removal drying system to remove VOC impurities and remove water from the mixed gas;

[0035] S4, catalyzing the mixed gas through a catalytic system, removing oxygen from the gas produced by the purification equipment through a deuterium gas purification system, and then passing through a deuterium gas detector to obtain a gas with a deuterium gas concentration of not less than 99%;

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

[0037] The S1 includes:

[0038] S1.1, start the vacuum pump and open the air receiving valve and air supply valve;

[0039] S1.2, adjusting the nitrogen replenishment amount through the mass flow controller;

[0040] S1.3, the amount of deuterium-nitrogen mixed gas 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 measures that the deuterium concentration in the mixed gas drops to 0, the vacuum pump stops working, and the air collection pneumatic valve and the air supply pneumatic valve are closed.

[0042] Beneficial effects: The present invention makes full use of energy, recovers and recycles deuterium gas and deuterium-nitrogen mixed gas from deuterium-containing waste gas, and saves costs; at the same time, the present invention sets a purification and recovery system to remove water, dry and remove VOC from the deuterium-nitrogen mixed gas discharged from the deuteration cabinet, so that the deuterium-nitrogen mixed gas can be recovered and utilized, and at the same time, a purification system is also set up, and the mixed gas is processed by the catalytic system, purification equipment and deuterium gas purification system in the purification system, so that the deuterium gas concentration can reach 99%, and at the same time, a deuterium gas detector is set up to adjust the concentration change in real time to meet the optical fiber processing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart of a method for recycling deuterium gas in optical fiber according to Example 1;

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

[0045] Figure 3 This is a flow chart of a method for recycling deuterium gas in optical fiber according to Example 2;

[0046] Figure 4 This is a structural schematic diagram of an optical fiber deuterium recycling system according to Example 2.

[0047] Among them, 01-air collection pneumatic valve, 02-air supply pneumatic valve, 03-return supply pneumatic valve, 04-air supply pneumatic valve. DETAILED DESCRIPTION

[0048] The present invention is further illustrated below in conjunction with specific embodiments. The embodiments are implemented based on the technical solutions of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used 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 gas recycling system, including a nitrogen gas replenishing device, a deuteration cabinet, a vacuum system, a compression system, a purification and recovery system, and a storage system.

[0051] Among them, the vacuum system includes an oil-free vacuum pump and a low-pressure buffer tank. After the optical fiber is deuterated in the deuterated cabinet, the vacuum pump evacuates the deuterated cabinet to -25kPa, extracts the deuterium-nitrogen mixed gas in the deuterated cabinet, and transports it to the low-pressure buffer tank, and then introduces nitrogen into the deuterated cabinet until the pressure of the deuterated cabinet reaches 20kPa, and then continues to evacuate the deuterated cabinet to -25kPa, extracts the deuterium-nitrogen mixed gas in the deuterated cabinet, and transports it to the buffer tank, and this is repeated three times. When the deuterium gas detector at the outlet of the vacuum pump measures that the deuterium concentration in the mixed gas drops to 0, the vacuum pump stops working, the 01 air collection valve and the 02 air supply valve are closed, and the deuterium-nitrogen mixed gas containing about 1.5% deuterium is recovered at the end of deuteration.

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

[0053] The deuterium-nitrogen mixed gas extracted from 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 drying system. The compressed deuterium nitrogen mixed gas is precooled by the precooling system, and then enters the VOC removal drying system to remove VOC and deoxygenate and dry, and then purified by the concentration system. The concentrated deuterium nitrogen mixed gas is tested for deuterium gas concentration by a deuterium gas detector. When the deuterium gas concentration is lower than 4.5%, the concentrated mixed gas returns to the low-pressure buffer tank after the vacuum pump, and continues to circulate and concentrate until the deuterium concentration of the gas purified and concentrated by the purification and concentration system reaches a product mixed gas of more than 4.5%. The mixed gas with a composite concentration is stored in a recovery tank and returned for deuteration.

[0055] When the pressure of the recovery storage tank meets the requirements for recycling, the deuteration cabinet is provided with recycling conditions. When the deuteration cabinet needs to add mixed deuterium, the 03 recycling valve is opened to supply the deuterium-nitrogen mixed gas in the recovery storage tank to the deuteration cabinet. When the pressure in the recovery tank does not meet the requirements for recycling, the 03 recycling valve is closed, and the fresh pure deuterium 04 gas supply valve from the deuterium gas bottle is opened to supply deuterium gas to the deuteration cabinet.

[0056] Example 2

[0057] like Figure 3 , Figure 4 As shown, this embodiment provides an optical fiber deuterium gas recycling system, including a nitrogen gas replenishing 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, the deuteration cabinet receives a signal indicating that the deuteration is complete, and the vacuum pump is started. The 01 air collection pneumatic valve and the 02 air supply pneumatic valve are opened, and the nitrogen supply amount is adjusted through the mass flow controller to balance the amount of deuterium-nitrogen mixed gas extracted by the vacuum pump and the amount of nitrogen supplied, so that the pressure of the deuteration cabinet is always maintained between ±100Pa. When the deuterium gas detector at the outlet of the vacuum pump measures that the deuterium concentration in the mixed gas drops to 0, the vacuum pump stops working, the 01 air collection valve and the 02 air supply valve are closed, and the collection is completed.

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

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

[0061] The compressed deuterium-nitrogen mixed gas passes through a precooling system to remove a portion of free water, enters a VOC removal drying system to remove VOC impurities and remove water from the mixed gas, and then passes through a catalytic system to catalyze the mixed gas to synthesize heavy water, the catalytic system includes a catalyst Pd or Pt; the catalytic system is connected to a heavy water electrolysis cell of a purification device, 60°C to 100°C is used for degassing, and then electrolysis is performed, the electrolyte is sodium deuterium oxide, the purification device is connected to a deuterium gas purification system, the deuterium gas purification system includes activated alumina plated with palladium, palladium carbon fiber catalyst, activated alumina and silver-X molecular sieve; the deuterium gas purification system is connected to a concentration system, a deuterium gas detector is also arranged between the concentration system and a storage tank, the storage tank is used to store gas with a deuterium gas concentration of not less than 99%, the gas is passed into a product storage tank for storage, and then is returned for deuteration.

[0062] When the purity and pressure of the pure deuterium in the product storage tank meet the requirements for recycling, the deuteration cabinet is given a condition for recycling. When the deuteration cabinet needs to add pure deuterium, the recycling valve is opened to supply the pure deuterium in the product storage tank to the deuteration cabinet for use. When the purity or pressure of the product in the product storage tank does not meet the requirements for recycling, the deuteration cabinet is given a condition for not recycling. When the deuteration cabinet needs to add pure deuterium, the recycling valve is closed, and the fresh pure deuterium supply valve from the deuterium gas bottle is opened to supply deuterium gas to the deuteration cabinet.

[0063] The above specific implementation methods further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above are only specific implementation methods of the present application and are not used to limit the protection scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the present application should be included in the protection scope of the present application.

Claims

1. An optical fiber deuterium gas recycling system, characterized in that: The optical fiber deuterium gas recycling system at least includes: a nitrogen gas supply 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 precooling system and a VOC removal and drying system, wherein: The nitrogen supply device is connected to the deuteration cabinet supply pneumatic valve via a mass flow controller, and is used to provide nitrogen to the deuteration cabinet; The vacuum system is connected to the deuteration cabinet air collecting pneumatic valve 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, which includes a precooling system for removing free water and a VOC removal and drying system for absorbing VOC gas and performing drying treatment, which are connected in sequence; The storage system is connected to the compression system and is used to store the purified recovered gas. The storage system is connected to the deuteration cabinet via a return pneumatic valve.

2. The optical fiber deuterium gas recycling system according to claim 1, characterized in that: The optical fiber deuterium gas recycling system is also provided with a purification system between the purification recovery system and the storage system.

3. The optical fiber deuterium gas recycling system according to claim 1 or 2, characterized in that: 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 gas purification system; the storage system includes a concentration system and storage tanks, and the storage tanks are recovery storage tanks and product storage tanks.

4. The optical fiber deuterium gas recycling system according to claim 3, characterized in that: The nitrogen replenishing device is connected to the deuteration cabinet replenishing pneumatic valve by adjusting the nitrogen replenishing amount through the mass flow controller; the deuteration cabinet air collecting pneumatic valve is connected to the oil-free vacuum pump for providing deuterium-nitrogen mixed gas; a deuterium gas detector is also arranged between the oil-free vacuum pump and the low-pressure buffer tank, and the low-pressure buffer tank is used to store the deuterium-nitrogen mixed gas; the low-pressure buffer tank compresses the deuterium-nitrogen mixed gas into the pressure buffer tank through the oil-free compressor; the pressure buffer tank is connected to the precooling system for removing free water; the precooling system is connected to the VOC removal drying system for removing VOC gas and water, and the VOC removal drying system includes two adsorption cylinders, which are used alternately, and the adsorption cylinders include ZSM-5 molecular sieve or β molecular sieve; the VOC removal drying system is connected to the concentration system, and a deuterium gas detector is also arranged between the concentration system and the storage tank, and the storage tank is used to store the deuterium-nitrogen mixed gas with a deuterium concentration greater than 4.5%.

5. The optical fiber deuterium gas recycling system according to claim 4, characterized in that: The VOC removal drying system is also connected to a catalytic system, which is used for catalytic synthesis of heavy water. The catalytic system includes a catalyst Pd or Pt; the catalytic system is connected to a purification device, which is used for degassing electrolysis. The purification device is a heavy water electrolysis cell. The temperature required for degassing is 60° C. to 100° C. The electrolyte in the electrolysis is sodium carbonate, potassium carbonate or sodium deuteride. The purification device is connected to a deuterium gas purification system, which includes a deoxygenation catalyst and an adsorbent. The deoxygenation catalyst is an activated alumina plated with palladium or a palladium carbon fiber catalyst, and the adsorbent is an activated alumina or a silver-X molecular sieve; the deuterium gas purification system is connected to a concentration system, and a deuterium gas detector is also provided between the concentration system and the storage tank. The storage tank is used to store gas with a deuterium gas concentration of not less than 99%.

6. An optical fiber deuterium recycling method, implemented based on the optical fiber deuterium recycling system according to claim 4, characterized in that: The steps include: S1, the deuteration of the deuteration cabinet is completed, and the deuteration cabinet is evacuated; S2, the deuterium-nitrogen mixed gas extracted from 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 mixed gas is precooled by the precooling system, then enters the VOC removal drying system, and is purified by the concentration system; S4, the concentrated deuterium-nitrogen mixed gas is stored in a recovery storage tank and is returned to deuteration.

7. The optical fiber deuterium recycling method according to claim 6, characterized in that: The S1 includes: S1.1 Evacuate the deuterated cabinet to -25kPa~-20kPa; S1.2 Deuterium-nitrogen mixed gas is transported to the buffer tank, and nitrogen is introduced until the pressure of the deuteration cabinet reaches 20kPa~25kPa; S1.3 Then evacuate the deuterated cabinet to -25kPa~-20kPa; S1.4 Draw out the deuterium-nitrogen mixed gas in the deuteration cabinet and transport it to the buffer tank. Repeat this process 2 to 3 times until the deuterium gas detector at the vacuum pump outlet measures that the deuterium gas concentration in the mixed gas drops to 0. Then the vacuum pump stops working and the air collection pneumatic valve and air supply pneumatic valve are closed.

8. The optical fiber deuterium recycling method according to claim 6, characterized in that: The S3 includes: S3.1, the compressed deuterium-nitrogen mixture is precooled by a precooling system; S3.2, enter the VOC removal and drying system to remove VOC, deoxidize and dry; S3.3, after being purified by the concentration system, the deuterium gas concentration is detected by a deuterium gas detector. When the deuterium gas concentration is lower than 4.5%, the concentrated mixed gas returns to the low-pressure buffer tank and continues to circulate and concentrate until the deuterium gas concentration in the gas after the concentration system reaches more than 4.5%.

9. An optical fiber deuterium recycling method, implemented based on the optical fiber deuterium recycling system of claim 5, characterized in that: The steps include: S1, the deuteration in the deuteration cabinet is completed and the vacuum pump is started; S2, the deuterium-nitrogen mixed gas extracted from the vacuum system is compressed by an oil-free compressor and then transported to a pressure buffer tank for storage; S3, after the compressed deuterium nitrogen mixed gas passes through a pre-cooling system to remove a portion of free water, it enters a VOC removal drying system to remove VOC impurities and remove water from the mixed gas; S4, catalyzing the mixed gas through a catalytic system, removing oxygen from the gas produced by the purification equipment through a deuterium gas purification system, and then passing through a deuterium gas detector to obtain a gas with a deuterium gas concentration of not less than 99%; S5, the concentrated gas is stored in a product storage tank and returned for deuteration.

10. The optical fiber deuterium recycling method according to claim 9, characterized in that: The S1 includes: S1.1, start the vacuum pump and open the air receiving valve and air supply valve; S1.2, adjusting the nitrogen replenishment amount through the mass flow controller; S1.3, the amount of deuterium-nitrogen mixed gas 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 measures that the deuterium concentration in the mixed gas drops to 0, the vacuum pump stops working, and the air collection pneumatic valve and the air supply pneumatic valve are closed.

Images