Method and equipment for preparing rough neon

Abstract

The invention provides a method and equipment for preparing crude neon, and relates to the technical field of industrial gas separation. The method comprises the steps of raw material gas acquisition and pretreatment, preliminary adsorption separation, low-temperature rectification separation, further purification and product collection and filling. According to the method, a covalent organic framework material is adopted as an adsorbent, adsorption and rectification conditions are optimized, and membrane separation and secondary adsorption purification technologies are combined, so that neon is efficiently extracted from synthesis ammonia tail gas. The equipment covers raw material gas collection, pretreatment, adsorption separation, rectification, deep purification and filling devices, is equipped with an automatic control system and a safety protection system, and ensures stable, efficient and safe operation. Through combination of multiple technologies, the neon recovery rate and purity are remarkably improved, and energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial gas separation, and specifically to a method and device for preparing crude neon gas. Background Art

[0002] In the field of industrial gas separation, neon gas, as a rare gas, has important application values. With the development of technology, the demand for neon gas is increasing day by day, especially in the fields of electronics industry, lighting, etc. However, the content of neon gas in the air is extremely low, only about 0.0018%, so efficiently separating and extracting neon gas from the air has always been a challenging task.

[0003] The existing methods for preparing crude neon gas mainly rely on cryogenic distillation technology. For example, Patent CN101218479B discloses a method and device for preparing crude neon gas, which mainly separates neon gas through the liquefaction and distillation of air. Specifically, after air is compressed, cooled and purified, it enters a distillation column for separation, and the preliminary purification of neon gas is achieved by utilizing the boiling point differences between neon gas and other gas components. However, this method has some limitations. First, simply relying on cryogenic distillation technology, it is difficult to achieve efficient separation and enrichment of neon gas, resulting in a low recovery rate of neon gas. Second, this process requires extremely low temperatures and high pressures, which makes the energy consumption of the equipment high and the operating cost expensive. In addition, due to the extremely low content of neon gas in the air, it is difficult to obtain high-purity neon gas only through the distillation step, and further purification treatment is required.

[0004] Another deficiency of the existing technology is the insufficient development of technologies for extracting neon gas from unconventional gas sources such as the tail gas generated during the production of synthetic ammonia. There is a certain amount of neon gas in the synthetic ammonia tail gas, but currently, there are no effective technologies and devices to efficiently recover this part of neon gas resources. This not only causes waste of resources but also keeps the production cost of neon gas high. Summary of the Invention

[0005] (I) Technical Problems to be Solved

[0006] In view of the deficiencies of the existing technology, the present invention provides a method and device for preparing crude neon gas, which solves the problems raised in the above background art.

[0007] (II) Technical Solutions

[0008] To achieve the above objectives, the present invention is realized through the following technical solutions: A method and device for preparing crude neon gas, comprising the following steps:

[0009] Step 1: Obtaining and pre-treating the raw gas: collecting the tail gas generated in the production process of synthetic ammonia and using it as the raw gas; then, performing dust removal, water removal and carbon dioxide removal operations on the raw gas in sequence to preliminarily purify the raw gas and obtain the pre-treated raw gas;

[0010] Step 2: Preliminary adsorption separation: The pretreated raw gas is input into an adsorption tower equipped with a special adsorbent, and the neon gas is adsorbed and enriched by the adsorbent; the adsorbent is a covalent organic framework material, and the adsorption time is 1-3 hours, until the concentration of neon gas increases to 3-5 times the initial concentration;

[0011] Step 3, low-temperature distillation separation: the neon-rich gas obtained after adsorption in step 2 is output from the bottom of the adsorption tower, and is cooled and decompressed in sequence, and then input into a low-temperature distillation tower for distillation separation, and a distillation tower top gas phase stream with neon as the main component is obtained through distillation separation;

[0012] Step 4, further purification: the gas phase flow from the top of the distillation tower obtained in step 3 is sequentially passed through a membrane separation unit and a second adsorption unit for deep separation and purification; in the membrane separation unit, an organic polymer separation membrane with high selectivity for neon is selected, and impurities such as nitrogen and argon are further removed under the condition of an operating pressure difference of 0.1-0.2MPa; then entering the second adsorption unit, using an adsorption column equipped with a special adsorbent, at a temperature of -20°C to 0°C and a pressure of 0.3-0.8MPa, the neon is adsorbed and purified again, and finally crude neon is obtained;

[0013] Step 5, product collection and filling: The crude neon gas obtained in step 4 is pressurized to a pressure of 15-20 MPa, and then transported to a gas buffer tank and a gas filling system in sequence, and finally filled into a gas cylinder to obtain a crude neon gas product.

[0014] Preferably, in step one, the dust removal operation is carried out using a filtration device with a filtration accuracy of not less than 5 μm, the water removal operation utilizes a molecular sieve adsorbent to perform adsorption and dehydration at a temperature of -40°C to -60°C, and the carbon dioxide removal operation adopts an amine absorption process, and the gas-liquid ratio in the absorption tower is controlled within the range of (500-1000):1.

[0015] Preferably, in step 2, the temperature in the adsorption tower is -10°C to 10°C and the pressure is 0.5-1.5MPa. In step 3, the cooling temperature is set to -100°C to -150°C, and the reduced pressure is set to 0.1-0.3MPa. During the distillation process, the top temperature of the distillation tower is -100°C to -140°C, the bottom temperature is -80°C to -120°C, and the reflux ratio is 1-3.

[0016] Preferably, the pore size of the covalent organic framework material is set to 0.3 - 0.5 nm, and the surface of the covalent organic framework material is modified with functional groups that can interact with neon molecules.

[0017] Preferably, the preparation method of the covalent organic framework material is as follows: First, 1,3,5-triformylphloroglucinol and p-phenylenediamine are put into a Pyrex tube of appropriate size. The molar mass ratio of 1,3,5-triformylphloroglucinol to p-phenylenediamine is 1:2. Then, the Pyrex tube is subjected to liquid nitrogen freezing and vacuum pumping treatment, and the vacuum pressure is set to 0.082 - 0.1 MPa. Finally, the Pyrex tube after liquid nitrogen freezing and vacuum pumping is sealed at a high temperature, and the sealing temperature is set to about 120 °C, and the reaction time is 72 hours.

[0018] Preferably, the post-treatment method of the covalent organic framework material is as follows: First, the prepared covalent organic framework material is washed by displacement with DMF solvent and then subjected to Soxhlet extraction and washing with methanol solvent to remove unreacted raw materials, by-products and other impurities, and then dried. Secondly, the washed and dried covalent organic framework material is placed in a muffle furnace and calcined at a certain temperature, and the calcined covalent organic framework material is activated under the protection of an inert gas atmosphere at a high temperature. Finally, the covalent organic framework material is subjected to a post-modification reaction with a reagent containing specific functional groups to introduce amino, carboxyl, and mercapto functional groups on the surface of the pre-existing pores of the covalent organic framework material.

[0019] An apparatus for preparing crude neon, which is applied to the above-mentioned method for preparing crude neon, includes:

[0020] A raw material gas collection and pretreatment device, including a gas collection hood, a gas buffer tank, a dust removal filter, a molecular sieve dryer, and an amine method absorption tower; an adsorption and separation device includes an adsorption tower, an adsorbent filling system, and a temperature and pressure control system; the adsorption tower is a multi-layer structure, and the inside is filled with a covalent organic framework material as an adsorbent, and a gas distribution plate is arranged between each layer of adsorbent to ensure that the raw material gas passes through the adsorbent layer evenly; the adsorbent filling system can accurately control the filling amount and filling position of the adsorbent; the temperature and pressure control system can control the temperature in the adsorption tower between -10 °C and 10 °C and the pressure between 0.5 - 1.5 MPa to achieve efficient adsorption and enrichment of neon.

[0021] Low-temperature rectification device, including a cooling system, a pressure reduction system and a rectification column; the cooling system adopts a multi-stage refrigeration unit and can cool the neon-rich gas to a low temperature of -100°C to -150°C; the pressure reduction system consists of a pressure reducing valve and a pressure regulator and can reduce the gas pressure to 0.1 - 0.3 MPa; the rectification column is internally provided with trays or packings, the top temperature can be controlled between -100°C and -140°C, the bottom temperature can be controlled between -80°C and -120°C, and the reflux ratio can be adjusted between 1 - 3 to achieve high-precision rectification separation of neon gas.

[0022] Deep separation and purification device, including a membrane separation unit and a second adsorption unit; the membrane separation unit is equipped with an organic polymer separation membrane with high selectivity for neon gas and can further remove impurities such as nitrogen and argon in the neon gas under an operating pressure difference of 0.1 - 0.2 MPa; the second adsorption unit is also a multi-layer adsorption structure and is internally equipped with a special adsorbent, and can adsorb and purify the neon gas again under the temperature condition of -20°C to 0°C and the pressure condition of 0.3 - 0.8 MPa.

[0023] Product collection and filling device, including a booster pump, a gas buffer tank, a filling system and gas cylinders; the booster pump can boost the crude neon gas to 15 - 20 MPa; the gas buffer tank is used to stabilize the pressure and flow rate of the boosted neon gas; the filling system is equipped with high-precision metering equipment and safety protection devices and can accurately fill the crude neon gas into the gas cylinders, and the gas cylinders meet relevant safety standards and specifications and can withstand a pressure of 15 - 20 MPa.

[0024] Preferably, it further includes:

[0025] Automation control system, which includes various sensors, transmitters, controllers and actuators; the sensors are used to monitor the temperature, pressure, flow rate, liquid level and other parameters of each part of the equipment in real time; the transmitters convert the signals detected by the sensors into standard signals and transmit them to the controllers; the controllers automatically control and adjust the equipment according to the preset process parameters and control algorithms; the actuators include various valves, pumps, motors, etc. and are used to execute the instructions issued by the controllers to achieve precise operation and operation management of the equipment and ensure the stability, high efficiency and safety of the entire preparation process;

[0026] Safety protection system, including explosion-proof devices, pressure relief devices, fire alarm devices, gas leakage detection devices, etc. The explosion-proof devices can prevent safety accidents caused by gas explosion inside the equipment. The pressure relief devices can automatically relieve pressure when the equipment pressure exceeds the set value to protect the safety of the equipment and personnel. The fire alarm devices and gas leakage detection devices can timely detect fire hazards and gas leakage situations around the equipment and send out alarm signals and take corresponding safety measures.

[0027] (III) Beneficial effects

[0028] The present invention provides a method and equipment for preparing crude neon gas, having the following beneficial effects:

[0029] 1. By combining adsorption separation technology and cryogenic distillation technology, and introducing covalent organic framework materials as adsorbents, the present invention can significantly improve the recovery rate and purity of neon gas. Compared with the prior art, the high-efficiency adsorption performance of covalent organic framework materials enables the concentration of neon gas to be efficiently enriched in the preliminary separation stage. After cryogenic distillation and subsequent deep purification steps, the obtained crude neon gas has a higher purity and a significantly increased recovery rate, effectively solving the problem of low recovery rate of neon gas in the prior art and better meeting the market demand for neon gas.

[0030] 2. The method and equipment of the present invention have obvious advantages in reducing energy consumption. By organically combining various technologies such as adsorption separation and cryogenic distillation, the separation process of neon gas is optimized, resulting in a significant reduction in the energy consumption of the entire preparation process. In contrast, the prior art solely relies on cryogenic distillation, which requires extremely low temperatures and high pressure conditions, leading to high equipment energy consumption. The multi-technology combination method of the present invention not only improves the separation efficiency but also reduces the dependence on extreme temperature and pressure conditions, thereby significantly reducing the production cost and improving the economic benefits of neon gas preparation. Description of the Drawings

[0031] Figure 1 It is a process schematic diagram of the present invention. Detailed Embodiments

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Step 1, acquisition and pretreatment of the raw material gas: The tail gas generated in the synthetic ammonia production process is collected and used as the raw material gas. Specifically, a gas collection hood is connected to the tail gas discharge port of the synthetic ammonia production device to collect the tail gas generated in the synthetic ammonia production process. The collected raw material gas sequentially passes through a dust removal filter (filter accuracy of 5 μm), a molecular sieve dryer (adsorbing and dehydrating at a temperature of -50°C), and an amine absorption tower (gas-liquid ratio controlled at 800:1) to remove solid impurity particles, moisture, and carbon dioxide in the raw material gas, obtaining the pretreated raw material gas.

[0034] Step 2, preliminary adsorption separation: The pretreated raw gas is input into an adsorption tower equipped with a covalent organic framework material. The temperature in the adsorption tower is controlled at 0°C and the pressure is controlled at 1.0MPa. The pore size of the covalent organic framework material is 0.4nm, and the surface is modified with amino functional groups. The adsorption time is 2 hours, and the concentration of neon gas adsorbed increases to 4 times the initial concentration.

[0035] Step 3, low temperature distillation separation: The deuterium-rich gas obtained after adsorption in step 2 is output from the bottom of the adsorption tower, passes through the cooling system (cooled to -120°C) and the decompression system (decompressed to 0.2MPa) in sequence, and then input into the low temperature distillation tower for distillation separation. During the distillation process, the top temperature of the distillation tower is controlled at -120°C, the bottom temperature is controlled at -100°C, and the reflux ratio is 2. Through distillation separation, a gas phase logistics with deuterium as the main component is obtained.

[0036] Step 4, further purification: The gas phase flow from the top of the distillation tower obtained in step 3 is sequentially passed through the membrane separation unit and the second adsorption unit for deep separation and purification. In the membrane separation unit, an organic polymer separation membrane with high selectivity for neon is selected to further remove impurities such as nitrogen and argon under the condition of an operating pressure difference of 0.15MPa. After that, it enters the second adsorption unit, and uses an adsorption column equipped with a special adsorbent to adsorb and purify neon again at a temperature of -10°C and a pressure of 0.5MPa to finally obtain crude neon.

[0037] Step 5, product collection and filling: The crude neon gas obtained in step 4 is pressurized to 18 MPa by a booster pump, then transported to the gas buffer tank and the filling system in sequence, and finally filled into a gas cylinder to obtain a crude neon gas product.

[0038] The method and device of the present invention were used to carry out neon gas preparation experiments. A total of 5 experiments were carried out, and the volume of raw gas processed in each experiment was 1000 cubic meters. The experimental results showed that the average recovery rate of neon gas reached 85% and the purity reached 98.5%. Compared with the prior art, the recovery rate of neon gas increased by 30% and the purity increased by 15%. At the same time, the energy consumption of the entire preparation process was reduced by 25%, which significantly improved the economic benefits of neon gas preparation.

[0039] Embodiment 2:

[0040] The difference between this embodiment and the first embodiment is that:

[0041] In step 1, the water removal operation uses a molecular sieve adsorbent to perform adsorption dehydration at a temperature of -40°C; the carbon dioxide removal operation adopts an amine absorption process, and the gas-liquid ratio in the absorption tower is controlled within the range of 500:1.

[0042] In Step 2, the temperature inside the adsorption tower is -5°C and the pressure is 0.8 MPa. The pore size of the covalent organic framework material is 0.3 nm, and the surface is modified with carboxyl functional groups. The adsorption time is 1 hour, and the adsorption is carried out until the concentration of neon gas increases to 3 times the initial concentration.

[0043] In Step 3, the cooling temperature is set at -100°C and the reduced pressure is set at 0.1 MPa. The temperature at the top of the distillation column is -100°C, the temperature at the bottom of the column is -80°C, and the reflux ratio is 1.

[0044] In Step 4, in the membrane separation unit, the operating pressure difference is 0.1 MPa. The second adsorption unit performs adsorption purification under the conditions of a temperature of -20°C and a pressure of 0.3 MPa.

[0045] In Step 5, the crude neon gas is pressurized to 15 MPa and then filled into gas cylinders.

[0046] In Example 2, 5 experiments were also carried out, and the volume of the raw material gas processed each time was 800 cubic meters. The experimental results show that the average recovery rate of neon gas is 80%, and the purity reaches 98%. Compared with the prior art, the recovery rate is increased by 25%, and the purity is increased by 12%. In addition, the energy consumption is reduced by 20%, effectively reducing the production cost.

[0047] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing crude neon gas, characterized in that, The following steps are involved: Step 1: Obtaining and pre-treating raw gas: collecting the tail gas generated in the synthetic ammonia production process and using it as raw gas; Then, the raw gas is subjected to dust removal, water removal and carbon dioxide removal operations in sequence to preliminarily purify the raw gas and obtain pretreated raw gas; Step 2: Preliminary adsorption separation: The pretreated raw gas is input into an adsorption tower filled with a special adsorbent, and the neon gas is adsorbed and enriched by the adsorbent; The adsorbent is a covalent organic framework material, and the adsorption time is 1-3 hours, until the concentration of neon increases to 3-5 times of the initial concentration; Step 3, low-temperature distillation separation: the neon-rich gas obtained after adsorption in step 2 is output from the bottom of the adsorption tower, and is cooled and decompressed in sequence, and then input into a low-temperature distillation tower for distillation separation, and a distillation tower top gas phase stream with neon as the main component is obtained through distillation separation; Step 4, further purification: the gas phase flow at the top of the distillation tower obtained in step 3 is sequentially passed through a membrane separation unit and a second adsorption unit for deep separation and purification; in the membrane separation unit, an organic polymer separation membrane with high selectivity for neon is selected, and impurities such as nitrogen and argon are further removed under the condition of an operating pressure difference of 0.1-0.2MPa; then entering the second adsorption unit, using an adsorption column equipped with a special adsorbent, at a temperature of -20°C to 0°C and a pressure of 0.3-0.8MPa, the neon is adsorbed and purified again to finally obtain crude neon; Step 5, product collection and filling: The crude neon gas obtained in step 4 is pressurized to a pressure of 15-20 MPa, and then transported to a gas buffer tank and a gas filling system in sequence, and finally filled into a gas cylinder to obtain a crude neon gas product.

2. The method for preparing crude neon gas according to claim 1, characterized in that: In step one, the dust removal operation is carried out using a filtering device with a filtering accuracy of not less than 5 μm, the water removal operation uses a molecular sieve adsorbent to perform adsorption and dehydration at a temperature of -40°C to -60°C, and the carbon dioxide removal operation adopts an amine absorption process, and the gas-liquid ratio in the absorption tower is controlled within the range of (500-1000):

1.

3. A method for preparing crude neon gas according to claim 1, characterized in that: In step 2, the temperature in the adsorption tower is -10°C to 10°C and the pressure is 0.5-1.5MPa. In step 3, the cooling temperature is set to -100°C to -150°C, and the reduced pressure is set to 0.1-0.3MPa. During the distillation process, the top temperature of the distillation tower is -100°C to -140°C, the bottom temperature is -80°C to -120°C, and the reflux ratio is 1-3.

4. A method for preparing crude neon gas according to claim 1, characterized in that: The pore size of the covalent organic framework material is set to 0.3-0.5 nm, and the surface of the covalent organic framework material is modified with functional groups that can interact with neon molecules.

5. A method for preparing crude neon gas according to claim 1, characterized in that: The preparation method of the covalent organic framework material is as follows. First, 1,3,5-triformylphloroglucinol and p-phenylenediamine are put into a Pyrex tube of appropriate size. The molar mass ratio of 1,3,5-triformylphloroglucinol to p-phenylenediamine is 1:

2. Then, the Pyrex tube is subjected to liquid nitrogen freezing and vacuum pumping treatment, and the pressure of vacuum pumping is set to 0.082 - 0.1 MPa. Finally, the Pyrex tube after liquid nitrogen freezing and vacuum pumping is sealed at a high temperature, and the sealing temperature is set to about 120°C, and the reaction time is 72 hours.

6. A method for preparing crude neon gas according to claim 1, characterized in that: The post-treatment method of the covalent organic framework material is as follows. First, the prepared covalent organic framework material is first replaced and washed with a DMF solvent, and then subjected to Soxhlet extraction and washing with a methanol solvent to remove unreacted raw materials, by-products and other impurities, and then dried. Secondly, the washed and dried covalent organic framework material is placed in a muffle furnace and calcined at a certain temperature, and the calcined covalent organic framework material is activated under the protection of an inert gas atmosphere at a high temperature. Finally, the covalent organic framework material is subjected to a post-modification reaction with a reagent containing specific functional groups to introduce amino, carboxyl, and mercapto functional groups on the surface of the pre-existing pores of the covalent organic framework material.

7. An apparatus for preparing crude neon gas, which is applied to a method for preparing crude neon gas as described in claims 1-6, characterized in that, Including: A raw material gas collection and pretreatment device, an adsorption and separation device, a low-temperature rectification device, a deep separation and purification device, and a product collection and filling device. The raw material gas collection and pretreatment device includes a gas collection hood, a gas buffer tank, a dust removal filter, a molecular sieve dryer, and an amine absorption tower. The adsorption and separation device includes an adsorption tower, an adsorbent filling system, and a temperature and pressure control system. The low-temperature rectification device includes a cooling system, a pressure reduction system, and a rectification tower. The deep separation and purification device includes a membrane separation unit and a second adsorption unit. The product collection and filling device includes a booster pump, a gas buffer tank, a filling system, and gas cylinders.

8. An apparatus for preparing crude neon gas according to claim 7, characterized in that, Also including: An automated control system, which includes various sensors, transmitters, controllers, and actuators; the sensors are used to monitor the temperature, pressure, flow rate, liquid level and other parameters of each part of the equipment in real time; the transmitters convert the signals detected by the sensors into standard signals and transmit them to the controller; the controller automatically controls and adjusts the equipment according to the preset process parameters and control algorithms; the actuators include various valves, pumps, motors, etc., which are used to execute the instructions issued by the controller to achieve precise operation and operation management of the equipment, and ensure the stability, high efficiency and safety of the entire preparation process. A safety protection system, including explosion-proof devices, pressure relief devices, fire alarm devices, gas leakage detection devices, etc. The explosion-proof devices can prevent safety accidents caused by gas explosion inside the equipment. The pressure relief devices can automatically relieve pressure when the equipment pressure exceeds the set value to protect the safety of the equipment and personnel. The fire alarm devices and gas leakage detection devices can timely detect fire hazards and gas leakage situations around the equipment, and send out alarm signals and take corresponding safety measures.

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