Medical high-purity oxygen purification process and system

Abstract

The invention discloses a medical high-purity oxygen purification process and system, the process takes industrial-grade oxygen as a raw material, adopts a four-section integrated process of pretreatment, low-temperature rectification, deep purification and sterile packaging, and removes particulate matters and oil mist through front three-stage filtration; water, carbon dioxide and part of hydrocarbons are efficiently removed through the double-bed adsorption tower, oxygen and nitrogen are accurately separated through the sieve plate rectifying tower, trace impurities and microorganisms are removed through activated carbon adsorption and ultraviolet sterile treatment, and finally high-purity oxygen meeting the medical standard is obtained through sterile packaging. According to the invention, the adsorbent ratio, the rectifying tower parameters and the sterile treatment flow are optimized, the product purity is greater than or equal to 99.5%, the dew point is less than or equal to-60 DEG C, the total hydrocarbon is less than or equal to 2ppm, the total bacterial count is less than or equal to 10CFU / m, and all indexes meet the national standard requirements of medical oxygen.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gas purification, and particularly relates to a medical high-purity oxygen purification process and system. BACKGROUND

[0002] Medical oxygen is an important material indispensable in clinical treatment and is widely used in scenes such as hypoxia disease treatment and surgical anesthesia assistance. The quality indexes such as purity and sterility of medical oxygen are directly related to the safety of patients. According to the standard requirements of “Medical Oxygen” (GB 8982-2014), the purity of medical oxygen needs to be ≥99.5%, the dew point needs to be ≤-60℃, and strict indexes such as oil-free, sterile, odor-free, total hydrocarbon content ≤2ppm, and total bacterial count ≤10CFU / m³ need to be met.

[0003] At present, the purification of medical oxygen is mostly based on industrial-grade oxygen as raw material, and the existing process mainly includes low-temperature rectification method, adsorption method, membrane separation method and the like. Among them, the low-temperature rectification method becomes the mainstream purification method due to high separation efficiency and stable product purity, but the existing low-temperature rectification process has the following shortcomings: first, the raw material gas pretreatment is not thorough enough, and the oil mist, fine particulate matter and trace impurities in industrial-grade oxygen are difficult to completely remove, which easily causes the subsequent rectification tower to be blocked and the equipment to be worn, and affects the product purity; second, the adsorbent regeneration parameter control is not accurate, which leads to rapid deactivation of the adsorbent, frequent replacement of the adsorbent not only increases the production cost, but also affects the production continuity; third, the rectification tower operation stability is poor, the tower pressure, temperature and reflux ratio fluctuate greatly, and problems such as liquid overflow and liquid leakage easily occur, which leads to product purity fluctuation; fourth, the sterilization process is not perfect, and some processes only use a single sterilization method, which is difficult to ensure that the microorganism removal meets the standards, and the equipment and pipelines are easy to cause secondary pollution; fifth, there are loopholes in safety protection measures, the risk of combustion and explosion caused by oxygen leakage is high, and there is a lack of effective real-time monitoring and emergency treatment mechanism.

[0004] In addition, the structure design of the existing medical oxygen purification system is relatively dispersed, the coordination between each unit is poor, the operation process is complicated, the production efficiency is low, and it is difficult to meet the demand of large-scale production. At the same time, the detection device of some systems is not comprehensive enough, and it is difficult to accurately detect various indexes of finished oxygen, which easily leads to unqualified products flowing into the market.

[0005] Therefore, it has become a technical problem to be solved in the current field to develop a medical high-purity oxygen purification process and system with high purification efficiency, stable product quality, safe and reliable operation, and suitable for large-scale production. SUMMARY

[0006] The purpose of the application is to overcome the shortcomings of the prior art, provide a medical high-purity oxygen purification process and system, so as to solve the problems of incomplete pretreatment, unstable distillation operation, poor sterilization effect, high safety risk and poor system synergy of the prior art, realize efficient, stable and safe production of medical high-purity oxygen, and ensure that various indexes of the product meet the medical standards.

[0007] The technical scheme of the application is a medical high-purity oxygen purification process, which comprises the following steps: (1) raw material gas pretreatment: industrial grade raw material oxygen is sequentially subjected to three-stage filtration, double-bed adsorption drying treatment to remove particulate matter, oil mist, moisture, carbon dioxide and part of hydrocarbon impurities; (2) low-temperature rectification separation: the pretreated gas is pre-cooled and liquefied, and then sent to a sieve plate rectification tower for oxygen-nitrogen rectification separation, nitrogen gas by-product is obtained at the top of the tower, and liquid crude oxygen is obtained at the bottom of the tower; (3) deep purification: after the liquid crude oxygen is gasified, it is sequentially subjected to active carbon adsorption tower to remove trace hydrocarbons, ultraviolet sterilizer to sterilize, and ceramic filter element to filter, so as to realize deep purification and sterilization treatment; (4) product storage and packaging: the deep-purified oxygen is stored in a medical storage tank, and after passing the detection, it is subjected to sterile filling to obtain medical high-purity oxygen product.

[0008] In some embodiments, the purity of the industrial grade raw material oxygen in step (1) is ≥99.2%, the moisture content is ≤1000ppm, the carbon dioxide content is ≤500ppm, the total hydrocarbon content is ≤100ppm, the solid particulate matter content is ≤1μm, and there is no oil stain, heavy metal or other toxic and harmful substances.

[0009] In some embodiments, the three-stage filtration in step (1) comprises coarse filtration, fine filtration and ultrafiltration, the coarse filtration uses a 5μm filter element, the fine filtration uses a 1μm filter element, and the ultrafiltration uses a 0.01μm polytetrafluoroethylene filter element; the process parameters of the three-stage filtration are: inlet pressure 0.8~1.0MPa, temperature 20~30℃, flow rate 50~100m³ / h, oil content in the filtered gas ≤0.01mg / m³, and the subsequent equipment is ensured not to be polluted by oil mist.

[0010] In some embodiments, the mixed adsorbent of 13X molecular sieve and activated alumina in the double-bed adsorption tower in step (1) is filled in a ratio of 1:1, with a particle size of 3-5 mm, wherein the static water adsorption capacity of 13X molecular sieve is ≥21%, and the specific surface area of activated alumina is ≥300 m² / g, which can assist in adsorbing moisture and part of hydrocarbon impurities. The double-bed adsorption tower uses an alternating adsorption and regeneration mode with a switching period of 4 hours to ensure continuous adsorption process. The adsorption process parameters are: adsorption pressure 0.7-0.9 MPa, temperature 25-35℃, and space velocity 1000-1500 h⁻¹; the adsorbent regeneration parameters are: regeneration temperature 200-220℃, regeneration time 2 hours, and regeneration gas flow rate 10% of the raw material gas. High-temperature regeneration can restore the adsorption performance of the adsorbent and avoid deactivation of the adsorbent. After adsorption and drying, the gas dew point is ≤-60℃, the carbon dioxide content is ≤1 ppm, and the part of hydrocarbon content is ≤5 ppm, effectively preventing the freezing and plugging problem of the subsequent low-temperature rectification system.

[0011] In some embodiments, the pre-cooling liquefaction in step (2) uses a plate-fin heat exchanger in cooperation with a low-temperature storage tank. The plate-fin heat exchanger has the characteristics of high heat exchange efficiency and compact structure, and can realize efficient heat exchange between the pretreated gas and the reflux oxygen and nitrogen. The pre-cooling temperature is controlled at -150~-160℃. Subsequently, the gas enters the liquefier for indirect heat exchange with liquid nitrogen. The liquefaction pressure is 0.5-0.6 MPa, the refrigerant is liquid nitrogen with a purity of ≥99.99%, and the refrigeration capacity is 50-80 kW. After pre-cooling and liquefaction, the liquefaction rate of the pretreated gas is ≥95%, and the temperature of the liquid mixed gas is -183℃, laying a foundation for subsequent rectification separation.

[0012] In some embodiments, the sieve plate rectification tower in step (2) is the core equipment for oxygen-nitrogen separation. The tower height is 15-20 m, the tower diameter is 0.8-1.2 m, the sieve plate number is 80-100, the sieve plate is made of stainless steel, the sieve hole diameter is 3-5 mm, and the hole spacing is 10-15 mm, which can ensure that the gas-liquid two phases are fully contacted in the tower. The process parameters of the rectification tower are strictly controlled as follows: tower top pressure 0.15-0.2 MPa, tower bottom pressure 0.2-0.25 MPa, tower top temperature -195.8℃ (nitrogen boiling point), tower bottom temperature -182.9℃ (oxygen boiling point), reflux ratio 3-5 (reflux liquid amount to distillate amount ratio), reboiler heating power 10-15 kW, and condenser cooling power 8-12 kW. The liquid mixed gas (oxygen-nitrogen molar ratio about 21:79) is fed from the middle of the rectification tower, and the gas-liquid countercurrent contact is realized in the tower. The reboiler at the bottom of the tower is heated to make part of the liquid vaporize, and the nitrogen content in the rising vapor increases. The condenser at the top of the tower is cooled to make part of the vapor liquefy, and the oxygen content in the reflux liquid increases. After multiple gas-liquid exchanges, the oxygen and nitrogen are accurately separated. Finally, the tower top produces nitrogen with a purity of ≥99.9%, which can be recycled as a byproduct; and the tower bottom produces liquid crude oxygen with a purity of ≥99.5%.

[0013] In some embodiments, in step (3), the activated carbon adsorption tower is filled with coal-based activated carbon, and the filling amount is 5-8 m³. The coal-based activated carbon has a large specific surface area and strong adsorption capacity, and can effectively adsorb residual hydrocarbons (such as methane, ethane, etc.) in the liquid crude oxygen. The adsorption process parameters are: pressure 0.2-0.3 MPa, temperature -180 to -170 ℃, flow rate 30-60 m³ / h, and space velocity 500-800 h⁻¹; after activated carbon adsorption, the total hydrocarbon content in the gas is ≤2 ppm, which avoids the accumulation of hydrocarbons in the oxygen to cause safety hazards.

[0014] In some embodiments, in step (3), sterile treatment adopts a combination of ultraviolet sterilization and ceramic filter element filtration to ensure complete removal of microorganisms. The liquid crude oxygen is first heated to 20-25 ℃ by a gasifier, which adopts an electric heating type with a heating power of 20-30 kW and a gasification efficiency of ≥98%. The gaseous oxygen enters an ultraviolet sterilizer, which has a power of 30-50 W and a wavelength of 254 nm. The ultraviolet light at this wavelength has strong sterilization capacity and can effectively kill bacteria, mold and other microorganisms, with a sterilization time of ≥3 seconds and a sterilization rate of ≥99.99%. Subsequently, the gas is filtered through a terminal ceramic filter element with a filtration precision of 0.2 μm and a filtration pressure of 0.1-0.2 MPa, which can further remove microbial debris and trace particulate matter after sterilization to ensure the sterile effect, and the total number of bacteria in the filtered gas is ≤10 CFU / m³.

[0015] In some embodiments, in step (4), the medical oxygen storage tank is made of 316L stainless steel, which has excellent corrosion resistance and sanitary performance, and can avoid contamination of the oxygen by the storage tank. The storage tank has a volume of 5-20 m³, a storage pressure of 0.8-1.0 MPa, and a temperature of 20-30 ℃. To ensure the cleanliness and sterility of the storage tank, it is cleaned and disinfected once a month with 30% food-grade hydrogen peroxide solution, and then dried by blowing sterile nitrogen gas. The storage tank is equipped with a pressure safety valve (jumping pressure 1.3 MPa), a liquid level gauge and a thermometer to monitor the pressure, liquid level and temperature in the storage tank in real time, ensuring storage safety.

[0016] The filling is performed on a medical oxygen filling platform with filling parameters of: filling pressure 12 MPa (cylinder pressure), and filling speed 5-8 m³ / h. Before filling, the cylinder needs to be subjected to strict pretreatment: first, a 22.5 MPa water pressure test is performed to detect the pressure resistance of the cylinder to ensure that there is no leakage; then, drying treatment is performed to make the dew point in the cylinder ≤-40 ℃, avoiding the influence of moisture in the cylinder on the quality of the finished oxygen.

[0017] The finished product detection adopts a multi-dimensional detection method, and the detection device includes a gas chromatograph, a dew point instrument, a microorganism detector and an infrared photometer, which respectively detect the purity, dew point, total bacterial count and oil content of the finished product oxygen. The finished product detection indexes need to meet: purity ≥ 99.5% (V / V), dew point ≤-60℃, carbon dioxide ≤1ppm, total hydrocarbon ≤2ppm, oil content ≤0.01mg / m³, total bacterial count ≤10CFU / m³, no odor, no visible impurities. Only after the detection is qualified, the factory can be labeled, so as to ensure that the product quality meets the medical standard.

[0018] In another aspect, the application also discloses a medical high-purity oxygen purification system, which comprises a raw gas pretreatment unit, a low-temperature rectification separation unit, a deep purification unit, a finished product storage and packaging unit and a safety control unit; all the equipment and pipelines in contact with oxygen are made of 304 or 316L stainless steel material, which avoids the pollution of the equipment to oxygen and improves the corrosion resistance and safety of the equipment.

[0019] The raw gas pretreatment unit comprises three-stage filters, a double-bed adsorption tower and an adsorbent regeneration device connected in sequence; the three-stage filters comprise 5μm coarse filter cartridges, 1μm fine filter cartridges and 0.01μm polytetrafluoroethylene ultrafiltration filter cartridges connected in sequence, which remove the particulate matters and oil mist in the raw gas step by step. The double-bed adsorption tower is two adsorption towers arranged side by side, which adopts an alternating adsorption and regeneration mode, and the switching period is 4 hours, so that the adsorption process can be continuously carried out, and the tower is filled with mixed adsorbents of 13X molecular sieve and activated alumina with a filling ratio of 1:1. The adsorbent regeneration device comprises a heater, a regeneration gas circulation pipeline and an adsorbent replacement reminding module; the heater adopts an electric heating type structure, the heating temperature precision is controlled within ±5℃, the regeneration temperature can be accurately controlled to 200-220℃, the regeneration gas circulation pipeline is provided with a flow regulating valve, the regeneration gas flow can be accurately controlled to 10% of the raw gas, and the adsorbent replacement reminding module triggers a replacement reminder once every 6 months, so that the adsorbent is not deactivated due to long-term use, and the adsorption effect is ensured.

[0020] The low-temperature rectification separation unit comprises a plate-fin heat exchanger, a liquefier, a sieve plate rectification tower, a tower top condenser and a tower bottom reboiler; the plate-fin heat exchanger is made of aluminum alloy material, has a heat exchange area of 50-80 m2 and a heat exchange efficiency of ≥95%, and can realize efficient heat exchange of the pretreated gas and the reflux gas. The liquefier is connected with a liquid nitrogen storage tank and is provided with a liquid nitrogen level monitoring and automatic supply device, so that the liquid nitrogen level can be monitored in real time, and the liquefaction process can be stably carried out when the liquid level is lower than the set value. The sieve plate in the sieve plate rectification tower is made of stainless steel material, has a sieve hole diameter of 3-5 mm, a hole spacing of 10-15 mm, a tower height of 15-20 m, a tower diameter of 0.8-1.2 m and a sieve plate number of 80-100; the tower top condenser is cooled by liquid nitrogen and has a cooling power of 8-12 kW; and the tower bottom reboiler is heated by electricity and has a heating power of 10-15 kW. The rectification tower is provided with a parameter monitoring module to monitor the tower pressure, temperature and reflux ratio in real time, and the reflux ratio fluctuation is controlled within ±0.5, so that the process parameters can be adjusted in time, the problems of liquid flooding or liquid leakage in the tower can be avoided, and the rectification separation can be stably carried out.

[0021] The deep purification unit comprises a gasifier, an activated carbon adsorption tower, an ultraviolet sterilizer and a terminal ceramic filter; the gasifier is an electric heating type gasifier, has a heating power of 20-30 kW, can quickly heat the liquid oxygen to 20-25℃, and has a gasification efficiency of ≥98%. The activated carbon adsorption tower is filled with coal-based activated carbon, has a filling amount of 5-8 m3, and is provided with a temperature and pressure monitoring device to monitor the adsorption process parameters in real time. The ultraviolet sterilizer has a power of 30-50 W and a wavelength of 254 nm, and is provided with a sterilization time control module to ensure that the sterilization time is ≥3 seconds. The terminal ceramic filter has a ceramic filter precision of 0.2 μm and is provided with a differential pressure monitoring device to remind replacement when the filter differential pressure exceeds the set value, so as to ensure the filtering effect.

[0022] The finished product storage and packaging unit comprises a medical oxygen storage tank, a filling table and a detection device; a pressure safety valve is arranged on the medical oxygen storage tank, the rectification tower and other key equipment to ensure that the pressure in the equipment does not exceed the rated value and avoid safety accidents caused by overpressure. An oxygen concentration monitor is arranged in the production workshop, and the alarm value is ≤23%; when the oxygen concentration in the workshop exceeds the alarm value, an alarm signal is sent in time to remind the staff to take measures. A nitrogen blowing device is connected to the vent of each equipment and pipeline for blowing replacement during system start and stop to avoid the mixing of oxygen and air to form an explosive mixture. An explosion-proof membrane is arranged in the vent pipeline of the rectification tower and the storage tank, and the burst pressure is 1.5 times of the rated pressure of the corresponding equipment; when the pressure in the equipment increases sharply, the explosion-proof membrane is broken to release the pressure and protect the safety of the equipment. The emergency stop device can trigger emergency stop, cut off the raw material gas supply and start nitrogen blowing when the oxygen concentration monitor alarms, the equipment pressure exceeds the standard or leakage occurs, so as to minimize the safety risk.

[0023] The safety control unit comprises a pressure safety valve, an oxygen concentration monitor, a nitrogen purging device and an explosion-proof membrane. The pressure safety valve is arranged on key equipment such as a medical oxygen storage tank and a rectifying tower, so as to ensure that the pressure in the equipment does not exceed the rated value and avoid overpressure to cause a safety accident. The oxygen concentration monitor is arranged in the production workshop, and the alarm value is ≤23%. When the oxygen concentration in the workshop exceeds the alarm value, an alarm signal is sent in time to remind the staff to take measures. The nitrogen purging device is connected to the vent of each device and pipeline, and is used for purging replacement during system start and stop, so as to avoid mixing of oxygen and air to form an explosive mixture. The explosion-proof membrane is arranged in the vent pipeline of the rectifying tower and the storage tank, and the burst pressure is 1.5 times the rated pressure of the corresponding equipment. When the pressure in the equipment increases sharply, the explosion-proof membrane is broken to release pressure, thereby protecting the safety of the equipment. The emergency stop device can trigger emergency stop, cut off the raw gas supply and start nitrogen purging when the oxygen concentration monitor alarms, the equipment pressure exceeds the standard or leakage occurs, thereby minimizing the safety risk.

[0024] Advantages: Compared with the prior art, the present application has the following advantages: (1) The pretreatment effect is remarkable: the pretreatment method combining three-stage filtration with double-bed adsorption drying is adopted, the three-stage filtration can remove particulate matter and oil mist step by step, and the oil content is controlled to be below 0.01 mg / m³; the double-bed adsorption tower adopts a mixed adsorbent with an optimized ratio, and cooperates with accurate regeneration parameters, so that water, carbon dioxide and part of hydrocarbons can be effectively removed, the dew point is ≤-60 ℃, and the carbon dioxide is ≤1 ppm, thereby providing high-quality raw gas for subsequent rectification separation, and avoiding equipment blockage and wear.

[0025] (2) The rectification separation efficiency is high and the stability is good: the structure parameters and operation parameters of the sieve plate rectifying tower are optimized, the sieve plate is reasonably designed, the gas-liquid contact is sufficient, the reflux ratio fluctuation is controlled to be within ±0.5, the problems such as liquid flooding and liquid leakage can be effectively avoided, the oxygen-nitrogen separation efficiency is high, the purity of the liquid crude oxygen output from the tower bottom is ≥99.5%, and the purity of the nitrogen gas at the tower top is ≥99.9%, which can be recovered as a byproduct, thereby improving the resource utilization rate.

[0026] (3) The deep purification and sterilization effect are reliable: trace hydrocarbons are removed by activated carbon adsorption, and the total hydrocarbon content is ≤2 ppm; the sterilization rate is ≥99.99% by combining ultraviolet sterilization with ceramic filter element filtration, and the total number of bacteria is ≤10 CFU / m³, so that the finished oxygen gas is impurity-free and sterile, meets the medical standards, and avoids secondary pollution.

[0027] (4) The safety protection is perfect: multiple safety protection measures such as a pressure safety valve, an oxygen concentration monitor, a nitrogen purging device, an explosion-proof membrane and an emergency stop device are arranged, the parameters such as pressure and oxygen concentration in the production process can be monitored in real time, sudden situations can be responded in time, the risk of combustion and explosion caused by oxygen leakage can be effectively prevented, and the production safety can be ensured.

[0028] (5) System synergy, high production efficiency: the structure of each unit of the system is compact, and the operation process is highly automated. The adsorbent regeneration, rectification parameter adjustment, and filling control are all precisely controlled, and the production continuity is strong, which is suitable for large-scale medical high-purity oxygen production. At the same time, a comprehensive detection device is provided to accurately detect various indicators of the finished product and ensure stable product quality.

[0029] (6) Long service life, low maintenance cost: all equipment and pipelines in contact with oxygen are made of 304 or 316L stainless steel, which is highly corrosion-resistant and has a long service life. The adsorbent regeneration efficiency is high, and it is replaced every 6 months, reducing the frequency of adsorbent replacement and reducing maintenance costs. Each device in the system is equipped with a monitoring and reminding module to facilitate timely maintenance and reduce downtime. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0031] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship shown, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the present application.

[0032] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] The present application will be further described in detail below through specific examples and in conjunction with the embodiments. EMBODIMENT

[0034] The present embodiment provides a medical high-purity oxygen purification process, and the specific steps are as follows: (1) Raw gas pretreatment The industrial grade oxygen is selected as the raw gas, with purity of 99.3%, moisture content of 800 ppm, carbon dioxide of 40 ppm, total hydrocarbon (calculated as methane) of 80 ppm, solid particles of 0.8 μm, no oil stain, heavy metal and other toxic and harmful substances.

[0035] The raw gas is sequentially filtered by three stages: 5 μm coarse filter filter core filter to remove large particle impurities, 1 μm fine filter filter core filter to filter small particles, and 0.01 μm polytetrafluoroethylene ultrafilter filter core filter to remove oil mist and colloids; the inlet pressure of the three-stage filtration is 0.9 MPa, the temperature is 25 ℃, and the flow rate is 80 m³ / h; the oil content of the filtered gas is 0.008 mg / m³.

[0036] The filtered gas enters a double-bed adsorption tower, which is filled with a mixed adsorbent of 13X molecular sieve and activated alumina at a filling ratio of 1:1, with a particle size of 4 mm, a static water adsorption capacity of 13X molecular sieve of 22%, and a specific surface area of activated alumina of 320 m² / g; the adsorption pressure of the double-bed adsorption tower is 0.8 MPa, the temperature is 30 ℃, the space velocity is 1200 h⁻¹, and the switching period is 4 hours; the regeneration temperature of the adsorbent is 210 ℃, the regeneration time is 2 hours, and the regeneration gas flow rate is 10% of the raw gas; after adsorption and drying, the dew point of the gas is -62 ℃, the carbon dioxide content is 0.8 ppm, and the partial hydrocarbon content is 4 ppm.

[0037] (2) Low-temperature rectification separation The pretreated gas enters a plate-fin heat exchanger and is pre-cooled to -155 ℃, and then enters a liquefier for indirect heat exchange with liquid nitrogen with a purity of 99.995%, at a liquefaction pressure of 0.55 MPa and a refrigeration capacity of 65 kW; the gas liquefaction rate is 96%, and the temperature of the liquid mixed gas is -183 ℃.

[0038] The liquid mixed gas is fed from the middle of a sieve plate rectification tower, which has a tower height of 18 m, a tower diameter of 1.0 m, 90 sieve plates, a sieve plate material of stainless steel, a sieve hole diameter of 4 mm, and a hole spacing of 12 mm; the tower top pressure of the rectification tower is 0.18 MPa, the tower bottom pressure is 0.22 MPa, the tower top temperature is -195.8 ℃, the tower bottom temperature is -182.9 ℃, the reflux ratio is 4, the reboiler heating power is 12 kW, and the condenser cooling power is 10 kW; after rectification separation, the nitrogen gas at the tower top has a purity of 99.92%, and the liquid crude oxygen at the tower bottom has a purity of 99.6%.

[0039] (3) Deep purification The liquid crude oxygen is heated to 22 ℃ by an electric heating type gasifier, which has a heating power of 25 kW and a gasification efficiency of 98.5%; the gaseous oxygen enters an activated carbon adsorption tower, which is filled with coal-based activated carbon with a filling amount of 6.5 m³, an adsorption pressure of 0.25 MPa, a temperature of -175 ℃, a flow rate of 45 m³ / h, and a space velocity of 650 h⁻¹; after adsorption, the total hydrocarbon content in the gas is 1.8 ppm.

[0040] Subsequently, the gas enters an ultraviolet sterilizer with a power of 40 W, a wavelength of 254 nm, a sterilization time of 3.5 seconds, and a sterilization rate of 99.992%; and then is filtered through a 0.2 μm ceramic filter with a filtration pressure of 0.15 MPa; and the total number of bacteria in the filtered gas is 8 CFU / m³.

[0041] (4) Product storage and packaging The deeply purified oxygen is stored in a 316L stainless steel medical storage tank with a volume of 15 m³, a storage pressure of 0.9 MPa, and a temperature of 25°C; and the storage tank is cleaned and disinfected once a month using 30% food-grade hydrogen peroxide solution.

[0042] During filling, the filling table has a filling pressure of 12 MPa and a filling speed of 6.5 m³ / h; and before filling, the gas cylinder is subjected to a 22.5 MPa water pressure test and dried to have a dew point of -42°C.

[0043] The detection results of the finished product are as follows: purity 99.6% (V / V), dew point -62°C, carbon dioxide 0.8 ppm, total hydrocarbons 1.8 ppm, oil content 0.008 mg / m³, total number of bacteria 8 CFU / m³, no odor, no visible impurities, and all indexes meet the requirements of "Medical Oxygen" (GB8982-2014). Embodiment

[0044] The embodiment provides a medical high-purity oxygen purification process, and the specific steps are as follows: (1) Raw gas pretreatment Industrial-grade oxygen is selected as the raw gas, which has a purity of 99.2%, a water content of 900 ppm, carbon dioxide of 45 ppm, total hydrocarbons (calculated as methane) of 90 ppm, solid particulate matter of 0.9 μm, no oil stains, and no toxic and harmful substances such as heavy metals.

[0045] The raw gas is sequentially filtered through three-stage filters: a 5 μm coarse filter cartridge filter, a 1 μm fine filter cartridge filter, and a 0.01 μm polytetrafluoroethylene ultrafilter cartridge filter; the inlet pressure of the three-stage filter is 0.8 MPa, the temperature is 22°C, and the flow rate is 60 m³ / h; and the oil content of the filtered gas is 0.009 mg / m³.

[0046] The filtered gas enters a double-bed adsorption tower filled with a mixed adsorbent of 13X molecular sieve and activated alumina at a ratio of 1:1, the particle size of the adsorbent is 3 mm, the static water adsorption capacity of the 13X molecular sieve is 21%, and the specific surface area of the activated alumina is 300 m² / g; the adsorption pressure of the double-bed adsorption tower is 0.7 MPa, the temperature is 25°C, the space velocity is 1000 h⁻¹, and the switching period is 4 hours; the regeneration temperature of the adsorbent is 200°C, the regeneration time is 2 hours, and the regeneration gas flow rate is 10% of the raw gas; after the adsorption and drying treatment, the dew point of the gas is -60°C, the carbon dioxide content is 1 ppm, and the partial hydrocarbon content is 5 ppm.

[0047] (2) Low-temperature rectification separation The pretreated gas enters a plate-fin heat exchanger and is precooled to -150°C, and then enters a liquefier to exchange heat indirectly with liquid nitrogen with a purity of 99.99%, the liquefaction pressure is 0.5 MPa, and the refrigeration capacity is 50 kW; the gas liquefaction rate is 95%, and the temperature of the liquid mixed gas is -183°C.

[0048] The liquid mixed gas is fed from the middle of the sieve plate rectification tower, the sieve plate rectification tower has a tower height of 15 m, a tower diameter of 0.8 m, 80 sieve plates, the sieve plates are made of stainless steel, the sieve hole diameter is 3 mm, and the hole spacing is 10 mm; the tower top pressure of the rectification tower is 0.15 MPa, the tower bottom pressure is 0.2 MPa, the tower top temperature is -195.8°C, the tower bottom temperature is -182.9°C, the reflux ratio is 3, the reboiler heating power is 10 kW, and the condenser cooling power is 8 kW; after rectification separation, the nitrogen gas with a purity of 99.9% is obtained at the tower top, and the liquid crude oxygen with a purity of 99.5% is obtained at the tower bottom.

[0049] (3) Deep purification The liquid crude oxygen is heated to 20°C by an electric heating vaporizer, the vaporizer heating power is 20 kW, and the vaporization efficiency is 98%; the gaseous oxygen enters an activated carbon adsorption tower, the adsorption tower is filled with coal-based activated carbon with a filling amount of 5 m³, the adsorption pressure is 0.2 MPa, the temperature is -180°C, the flow rate is 30 m³ / h, and the space velocity is 500 h⁻¹; after adsorption, the total hydrocarbon content in the gas is 2 ppm.

[0050] Subsequently, the gas enters an ultraviolet sterilizer, the sterilizer power is 30 W, the wavelength is 254 nm, the sterilization time is 3 seconds, and the sterilization rate is 99.99%; then the gas is filtered through a 0.2 μm ceramic filter element at a filtration pressure of 0.1 MPa; after filtration, the total number of bacteria in the gas is 10 CFU / m³.

[0051] (4) Product storage and packaging The oxygen after deep purification is stored in a 316L stainless steel medical storage tank with a volume of 5 m³, a storage pressure of 0.8 MPa, and a temperature of 20°C; the tank is cleaned and disinfected once a month using 30% food-grade hydrogen peroxide solution.

[0052] During filling, the filling table has a filling pressure of 12 MPa and a filling speed of 5 m³ / h; before filling, the gas cylinder is subjected to a 22.5 MPa water pressure test and dried to have a dew point of -40°C.

[0053] The product detection results are as follows: purity 99.5% (V / V), dew point -60°C, carbon dioxide 1 ppm, total hydrocarbon 2 ppm, oil content 0.009 mg / m³, total number of bacteria 10 CFU / m³, no odor and no visible impurities, and all indexes meet the requirements of Medical Oxygen (GB8982-2014). Example

[0054] The embodiment provides a medical high-purity oxygen purification process, and specific steps are as follows: (1) Raw gas pretreatment Industrial-grade oxygen is selected as the raw gas, the purity of which is 99.5%, the water content is 700 ppm, the carbon dioxide content is 30 ppm, the total hydrocarbon (calculated by methane) content is 70 ppm, the solid particle content is 0.7 μm, and there is no oil stain, heavy metal or other toxic and harmful substances.

[0055] The raw gas is sequentially filtered by three-stage filters: a 5 μm coarse filter, a 1 μm fine filter and a 0.01 μm polytetrafluoroethylene ultrafilter; the inlet pressure of the three-stage filter is 1.0 MPa, the temperature is 30 ℃, and the flow rate is 100 m³ / h; and the oil content of the filtered gas is 0.007 mg / m³.

[0056] The filtered gas enters a double-bed adsorption tower, which is filled with a mixed adsorbent of 13X molecular sieve and activated alumina at a filling ratio of 1:1, the particle size of the adsorbent is 5 mm, the static water adsorption capacity of the 13X molecular sieve is 23%, and the specific surface area of the activated alumina is 330 m² / g; the adsorption pressure of the double-bed adsorption tower is 0.9 MPa, the temperature is 35 ℃, the space velocity is 1500 h⁻¹, and the switching period is 4 hours; the regeneration temperature of the adsorbent is 220 ℃, the regeneration time is 2 hours, and the regeneration gas flow rate is 10% of the raw gas; after the adsorption and drying treatment, the dew point of the gas is -63 ℃, the carbon dioxide content is 0.7 ppm, and the partial hydrocarbon content is 3 ppm.

[0057] (2) Low-temperature rectification separation The pretreated gas enters a plate-fin heat exchanger and is pre-cooled to -160 ℃, and then enters a liquefier and is indirectly heat-exchanged with liquid nitrogen with a purity of 99.995%, the liquefaction pressure is 0.6 MPa, and the refrigeration capacity is 80 kW; the gas liquefaction rate is 97%, and the temperature of the liquid mixed gas is -183 ℃.

[0058] The liquid mixed gas is fed from the middle of a sieve plate rectification tower, the sieve plate rectification tower has a tower height of 20 m, a tower diameter of 1.2 m, 100 sieve plates, the sieve plates are made of stainless steel, the sieve hole diameter is 5 mm, and the hole spacing is 15 mm; the tower top pressure of the rectification tower is 0.2 MPa, the tower bottom pressure is 0.25 MPa, the tower top temperature is -195.8 ℃, the tower bottom temperature is -182.9 ℃, the reflux ratio is 5, the reboiler heating power is 15 kW, and the condenser cooling power is 12 kW; after the rectification separation, the nitrogen gas with a purity of 99.93% is obtained at the tower top, and the liquid crude oxygen with a purity of 99.7% is obtained at the tower bottom.

[0059] (3) Deep purification The liquid crude oxygen is heated to 25℃ by an electric heating gasifier, the heating power of the gasifier is 30kW, and the gasification efficiency is 99%; the gaseous oxygen enters an activated carbon adsorption tower, the activated carbon adsorption tower is filled with coal-based activated carbon, the filling amount is 8m³, the adsorption pressure is 0.3MPa, the temperature is-170℃, the flow rate is 60m³ / h, and the space velocity is 800h⁻¹; after adsorption, the total hydrocarbon content in the gas is 1.5ppm.

[0060] Subsequently, the gas enters an ultraviolet sterilizer, the sterilizer power is 50W, the wavelength is 254nm, the sterilization time is 4 seconds, and the sterilization rate is 99.995%; then the gas is filtered through a 0.2μm ceramic filter, and the filtration pressure is 0.2MPa; after filtration, the total number of bacteria in the gas is 6CFU / m³.

[0061] (4) Product storage and packaging The deeply purified oxygen is stored in a 316L stainless steel medical storage tank, the storage tank has a volume of 20m³, a storage pressure of 1.0MPa, and a temperature of 30℃; the storage tank is cleaned and disinfected once a month using 30% food-grade hydrogen peroxide solution.

[0062] During filling, the filling table has a filling pressure of 12MPa and a filling speed of 8m³ / h; before filling, the gas cylinder is subjected to a 22.5MPa water pressure test and dried to have a dew point of-43℃.

[0063] The product detection results are as follows: purity 99.7% (V / V), dew point-63℃, carbon dioxide 0.7ppm, total hydrocarbon 1.5ppm, oil content 0.007mg / m³, total number of bacteria 6CFU / m³, no odor and no visible impurities, and all indexes meet the requirements of "Medical Oxygen" (GB8982-2014). Embodiment

[0064] A system for purifying medical high-purity oxygen applied in Embodiment 1 to Embodiment 3 comprises a raw gas pretreatment unit, a low-temperature rectification separation unit, a deep purification unit, a product storage and packaging unit, and a safety control unit. The raw gas pretreatment unit comprises a three-stage filter, a double-bed adsorption tower, and an adsorbent regeneration device connected in sequence. The low-temperature rectification separation unit comprises a plate-fin heat exchanger, a liquefier, a sieve plate rectification tower, a tower top condenser, and a tower bottom reboiler. The deep purification unit comprises a gasifier, an activated carbon adsorption tower, an ultraviolet sterilizer, and a terminal ceramic filter. The product storage and packaging unit comprises a medical oxygen storage tank, a filling table, and a detection device. The safety control unit comprises a pressure safety valve, an oxygen concentration monitor, a nitrogen blowing device, and an anti-explosion membrane.

[0065] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the technical solution of the present application, can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, as long as it does not deviate from the technical solution of the present application, shall still fall within the scope of the technical solution of the present application.

Claims

1. A process for purifying high-purity medical oxygen, characterized in that: Includes the following steps: (1) Raw material gas pretreatment: Industrial grade raw material oxygen is sequentially filtered through three stages and dried by dual-bed adsorption to remove particulate matter, oil mist, moisture, carbon dioxide and some hydrocarbon impurities; (2) Low temperature distillation separation: The pretreated gas is precooled and liquefied, and then sent to a sieve plate distillation column for oxygen and nitrogen distillation separation. Nitrogen by-product is produced at the top of the column, and liquid crude oxygen is obtained at the bottom of the column. (3) Deep purification: After the liquid crude oxygen is oxidized, it is sequentially passed through an activated carbon adsorption tower to remove trace hydrocarbons, an ultraviolet sterilizer for sterilization, and a ceramic filter element for filtration, so as to achieve deep purification and sterilization. (4) Finished product storage and packaging: The deeply purified oxygen is stored in a medical storage tank. After passing the test, it is aseptically filled to obtain the finished medical high-purity oxygen product.

2. The medical high-purity oxygen purification process according to claim 1, characterized in that: The industrial-grade raw material oxygen mentioned in step (1) has a purity of ≥99.2%, a moisture content of ≤1000ppm, a carbon dioxide content of ≤500ppm, a total hydrocarbon content of ≤100ppm, a solid particulate matter content of ≤1μm, and is free from oil, heavy metals and other toxic and harmful substances.

3. The medical high-purity oxygen purification process according to claim 1, characterized in that: The three-stage filtration in step (1) includes coarse filtration, fine filtration and ultrafiltration. The coarse filtration uses a 5μm filter element, the fine filtration uses a 1μm filter element, and the ultrafiltration uses a 0.01μm polytetrafluoroethylene filter element. The process parameters of the three-stage filtration are: inlet pressure 0.8~1.0MPa, temperature 20~30℃, flow rate 50~100m³ / h, and oil content of the filtered gas ≤0.01mg / m³.

4. The medical high-purity oxygen purification process according to claim 1, characterized in that: The dual-bed adsorption tower described in step (1) is filled with a mixed adsorbent of 13X molecular sieve and activated alumina in a ratio of 1:

1. The adsorbent particle size is 3~5mm, wherein the static water adsorption capacity of 13X molecular sieve is ≥21%, and the specific surface area of ​​activated alumina is ≥300m² / g.

5. The process for purifying high-purity medical oxygen according to claim 1, characterized in that: In step (2), the pre-cooling liquefaction is carried out using a plate-fin heat exchanger in conjunction with a cryogenic storage tank. The pre-cooling temperature is -150~-160℃, the liquefaction pressure is 0.5~0.6MPa, the refrigerant is liquid nitrogen with a purity of ≥99.99%, and the cooling capacity is 50~80kW. After pre-cooling and liquefaction, the liquefaction rate of the pretreated gas is ≥95%, and the temperature of the liquid mixed gas is -183℃.

6. The process for purifying high-purity medical oxygen according to claim 1, characterized in that: The process parameters of the distillation column in step (2) are as follows: top pressure 0.15~0.2MPa, bottom pressure 0.2~0.25MPa, top temperature -195.8℃, bottom temperature -182.9℃, reflux ratio 3~5, reboiler heating power 10~15kW, condenser cooling power 8~12kW; the liquid mixed gas is fed from the middle of the distillation column, and after distillation separation, nitrogen with a purity ≥99.9% is produced at the top of the column, and liquid crude oxygen with a purity ≥99.5% is produced at the bottom of the column.

7. The process for purifying high-purity medical oxygen according to claim 1, characterized in that: The activated carbon adsorption tower in step (3) is filled with coal-based activated carbon with a filling amount of 5~8 m³. The process parameters are: pressure 0.2~0.3 MPa, temperature -180~-170℃, flow rate 30~60 m³ / h, space velocity 500~800 h⁻¹. After activated carbon adsorption, the total hydrocarbon content in the gas is ≤2 ppm.

8. A medical high-purity oxygen purification system, characterized in that: It includes a raw gas pretreatment unit, a low-temperature distillation and separation unit, a deep purification unit, a finished product storage and packaging unit, and a safety control unit; The raw gas pretreatment unit includes a three-stage filter, a dual-bed adsorption tower, and an adsorbent regeneration device connected in sequence. The low-temperature distillation and separation unit includes a plate-fin heat exchanger, a liquefier, a sieve plate distillation column, a top condenser, and a bottom reboiler. The deep purification unit includes a vaporizer, an activated carbon adsorption tower, an ultraviolet sterilizer, and a terminal ceramic filter. The finished product storage and packaging unit includes a medical oxygen storage tank, a filling station, and a testing device; The safety control unit includes a pressure safety valve, an oxygen concentration monitor, a nitrogen purging device, and an explosion-proof membrane.

9. A medical high-purity oxygen purification system according to claim 8, characterized in that: The sieve plates in the sieve plate distillation column are made of stainless steel, with a sieve hole diameter of 3~5mm and a hole spacing of 10~15mm; the top condenser is cooled by liquid nitrogen, and the bottom reboiler is electrically heated with a heating power of 10~15kW.

10. A medical high-purity oxygen purification system according to claim 8, characterized in that: The oxygen concentration monitor in the safety control unit is installed in the production workshop, with an alarm value of ≤23%; the nitrogen purging device is connected to the vent of each piece of equipment and pipeline for purging and replacement during system start-up and shutdown; the explosion-proof membrane is installed in the vent pipeline of the distillation column and storage tank, with a burst pressure of 1.5 times the rated pressure of the corresponding equipment.