变压吸附制氧

PSA oxygen

  变压吸附（PSA,VPSA）制氧机是一种新型高科技设备,它具有设备成本低，体积小、重量轻、操作简单、维护方便、运行费用小、现场制氧快捷、开关方便、无污染等优点,。空分制氧设备广泛运用于石油化工、电炉炼钢、玻璃生产、造纸、制取臭氧、水产养殖、航空航天、医疗保健等行业和领域，设备运行稳定，安全可靠，深受广大用户的青睐。 
2．PSA制氧工作原理： 
     变压吸附制氧机是以分子筛为吸附剂，利用加压吸附，降压解吸的原理从空气中吸附和释放氮气，从而分离出氧气的自动化设备。分子筛是一种经过特殊的孔型处理工艺加工而成的，表面和内部布满微孔的球形颗粒状吸附剂，呈白色。其孔型特性使其能够实现O2、N2的动力学分离。分子筛对O2、N2的分离作用是基于这两种气体的动力学直径的微小差别，N2分子在分子筛的微孔中有较快的扩散速率，O2分子扩散速率较慢。压缩空气中的水和CO2的扩散同氮相差不大。最终从吸附塔富集出来的是氧气分子。 
    变压吸附制氧正是利用分子筛的选择吸附特性，采用加压吸附，减压解吸的循环周期，使压缩空气交替进入吸附塔来实现空气分离，从而连续产出高纯度的产品氧气。 
3．PSA制氧基本工艺流程： 
空气经空压机压缩后，经过除尘、除油、干燥后，进入空气储罐，经过空气进气阀、左进气阀进入左吸附塔，塔压力升高，压缩空气中的氮分子被沸石分子筛吸附，未吸附的氧气穿过吸附床，经过左产气阀、氧气产气阀进入氧气储罐，这个过程称之为左吸，持续时间为几十秒。左吸过程结束后，左吸附塔与右吸附塔通过均压阀连通，使两塔压力达到均衡，这个过程称之为均压，持续时间为3~5秒。均压结束后，压缩空气经过空气进气阀、右进气阀进入右吸附塔，压缩空气中的氮分子被分子筛吸附，富集的氧气经过右产气阀、氧气产气阀进入氧气储罐，这个过程称之为右吸，持续时间为几十秒。同时左吸附塔中分子筛吸附的氧气通过左排气阀降压释放回大气当中，此过程称之为解吸。反之左塔吸附时右塔同时也在解吸。为使分子筛中降压释放出的氮气完全排放到大气中，氧气通过一个常开的反吹阀吹扫正在解吸的吸附塔，把塔内的氧气吹出吸附塔。这个过程称之为反吹，它与解吸是同时进行的。右吸结束后，进入均压过程，再切换到左吸过程，一直循环进行下去。 
制氧机的工作流程是由可编程控制器控制五个二位五通先导电磁阀，再由电磁阀分别控制七个气动管道阀的开、闭来完成的。五个二位五通先导电磁阀分别控制左吸、均压、右吸状态。左吸、均压、右吸的时间流程已经存储在可编程控制器中，在断电状态下，五个二位五通先导电磁阀的先导气都接通气动管道阀的关闭口。当流程处于左吸状态时，控制左吸的电磁阀通电，先导气接通左吸进气阀、左吸产气阀、右排气阀开启口，使得这三个阀门打开，完成左吸过程，同时右吸附塔解吸。当流程处于均压状态时，控制均压的电磁阀通电，其它阀关闭；先导气接通均压阀开启口，使得这阀门打开，完成均压过程。当流程处于右吸状态时，控制右吸的电磁阀通电，先导气接通右吸进气阀、右吸产气阀、左排气阀开启口，使得这三个阀门打开，完成右吸过程，同时左吸附塔解吸。每段流程中，除应该打开的阀门外，其它阀门都应处于关闭状态。 
4．PSA制氧系统设备 
4．1  空气压缩机 
因为PSA空分制氧是通过加压吸附、常压解吸从空气中直接制取氧气，所以空压机是提供气体压缩的动力源。目前广泛使用的空压机主要有螺杆空压机和活塞空压机两大类。这两种空压机各有其特点，都可用于制氧系统。一般来说，螺杆空压机气量损耗少，产气效率高，噪音低，维修量较小，但压缩空气中一般都含油，价格相对较高；活塞空压机现有无油润滑和有油润滑两种，对于制氧系统来说，最好配套使用无油润滑空压机。 
空压机的排气量根据制氧机的规格而定。一般为了不使空压机一直满负荷运转，有一定的卸载时间，有利于空压机长期有效使用，在选择空压机的排气量时，螺杆空压机的排气量一般要比制氧机要求的气量大10~15%，活塞空压机一般要比要求的排气量大20~25%。 
空压机的额定排气压力最好选择为0.5~0.7Mpa，排气压力过高、过低均不好。 
空压机排出的压缩空气中含油量必须≤10ppm w/w，最好使用无油空压机。 
PSA制氧系统中设备主要电力消耗就是空压机的功率消耗。 
4．2  压缩空气预处理设备 
因为制氧主机中分子筛对压缩空气的品质要求很高，而压缩空气中气体温度高，又含有大量的水分和一定的粉尘、油雾，所以在压缩空气进入制氧主机前必须进行除水、除油、除尘等处理，此部分设备主要就是为了此目的。 
对压缩空气的净化处理至关重要，这一点请用户千万不要忽视！因为压缩空气净化处理的好坏直接关系到分子筛的使用寿命，从而直接关系制氧机的长期有效使用。一旦分子筛油“中毒”，制氧机将效率下降，指标无法达到正常。 
对压缩空气除水主要采用吸附式干燥器。吸附式的无热再生干燥机是采用一种可再生的干燥剂作为吸附剂，利用压力变化、气体膨胀等原理，采用变压吸附分离水分的分离工艺，将压缩空气中的水分除去。 
如果要求氧气露点不是太低（≤—40℃常压），则不需要吸附式干燥器；如果要求氧气露点较低（≤—60℃常压），则需配置吸附式干燥器。吸附式干燥器有无热再生和微热再生两种类型，都对气量有一定损耗，一般采用无热再生干燥装置。 
对压缩空气除油、除尘主要采用不同类型、不同过滤精度的多级过滤器。过滤器是通过由很多微孔的纤维材料制成的滤芯或活性炭除去介质中的污染物（水、油、微粒、异味），所有过滤器都有除水、除油、除尘的作用，只不过不同类别的过滤器主要功能不同。主路过滤器主要起除尘和除液态水作用；初过滤器主要起一级除油作用；精过滤器主要是进一步除油，使介质含油量很少；活性炭除油过滤器主要是起深度除油和吸附碳氢化合物、除异味的作用。过滤器的配置主要根据空压机排出的压缩空气品质而定。配置太少，压缩空气得不到充分的净化处理，无法达到制氧机对压缩空气的品质要求，这是不允许的；配置太多，固然对压缩空气处理效果好，但会造成管路中气体压力损耗较多，同时也造成成本过高，没有必要。一般来说，对无油空压机，需配置一至两级过滤器，主要是除尘、除水；对含油空压机，则需配置三至四级过滤器。 
     
 制氧主机 
PSA制氧主机对压缩空气的要求如下： 
         压    力  ≥ 0.7Mpa , 
         残油含量  ≤ 0.008PPm, 
         机械杂质  ≤ 0.01mm   
        常压露点  ≤ —23℃ 
    制氧主机一般由罐体、管路阀门和电控柜三部分组成，具体地包括底盘、空气缓冲罐、氧气缓冲罐、吸附塔，沸石分子筛、布气系统、压紧装置，气动管道阀、电磁阀、单向管道阀、过滤减压阀等阀门，PLC控制器、高效消音器、测氧仪、流量计、压力表等仪器仪表，连接管路等附件。 
2． 工况条件 
环境温度：≤40℃ 
相对湿度：≤65% 
原料空气：机械杂质：≤20mg/m3 
          CO2含量：≤250ppm 
          C2H2含量：≤0.5ppm 
          CnHm含量：≤20ppm 
          不含刺鼻气味及腐蚀性气体 
电    源：3f380V、1f220V、50Hz 
 冷 却 水：水温：≤25℃，pH值：7~8，总硬度：≤3.2mmol/L， 
             悬浮物含量：≤100mg/L，进水压力：≥0.2Mpa 
3． 设备安装 
 设备安装由用户负责，我公司负责指导设备安装。 
所有设备就位后，设备之间的管路连接就根据实际情况现场配置。所有管路必须采用硬连接方式（螺纹连接或焊接），应由专业人员施工，以免发生泄漏现象。成品氧气出口至用 
将系统用电源和冷却水引至设备现场，备好配电盘、冷却水供应设施。变压供应设施。

PSA oxygen
  Pressure swing adsorption (PSA, VPSA) oxygen is a new high-tech equipment, it has a low equipment cost, small size, light weight, simple operation, easy maintenance, low operating costs, on-site oxygen fast, convenient switch, no pollution and other advantages. ASU oxygen equipment widely used in petrochemical, electric furnace steel, glass, paper, preparation of ozone, aquaculture, aerospace, medical care and other industries and fields, equipment operation and stability, safe and reliable, the majority of users of all ages .
2. PSA oxygen works:
     PSA oxygen machine is a molecular sieve adsorbent, the use of pressure adsorption, desorption principle buck adsorption and desorption of nitrogen from the air to separate the oxygen automation equipment. Zeolite is a kind of processed pass through a special treatment process, the surface and the interior covered with porous spherical particulate adsorbent white. Its features make it possible to pass to achieve O2, N2 separation kinetics. Separation of molecular sieves O2, N2 is based on small differences in kinetic diameter of these two gases, N2 molecules fast diffusion rate in the microporous molecular sieves, O2 molecular diffusion rate is slow. Water and compressed air in the diffusion of CO2 with nitrogen or less. Enrichment from the final out of the adsorption tower is molecular oxygen.
    PSA oxygen is the use of selective adsorption properties of molecular sieves, pressurized adsorption, desorption decompression cycle, the compressed air alternately into the adsorption tower to achieve air separation, thereby continuously output high purity oxygen product.
3. PSA oxygen basic process:
Compressor air is then compressed, after dust removal, degreasing, dry air entering the tank through the air inlet valve, the inlet valve into the left left adsorption column, column pressure increases, the compressed air is zeolite molecular nitrogen molecular sieve adsorption, unadsorbed oxygen passes through the adsorbent bed, left after production valve, the oxygen tank valve into the production of oxygen, a process known as the left suction, duration of tens of seconds. After completion of the process of absorbing the left, the left and right column adsorption adsorption column by equalizing valve in communication, so that the two column pressure equilibrium, a process known as grading, duration of 3 to 5 seconds. After equalizing the end of compressed air through the air inlet valve, the right intake valve into the right adsorber, compressed nitrogen molecules are molecular sieve adsorption, oxygen-enriched air valve through the right production, oxygen production valve into the oxygen tank this process is called a right suction, duration of tens of seconds. At the same time left oxygen adsorption by molecular sieve adsorption tower in the left exhaust valve is released back into the atmosphere among the buck, this process is called desorption. Conversely when the left and right column adsorption tower while also desorbed. For the molecular sieve is completely down release of nitrogen emissions into the atmosphere, the oxygen adsorption tower through a normally open purge valve purge are desorption tower blowing oxygen adsorption towers. This process is called blowback it and desorption are carried out simultaneously. Right after the end of the aspiration into the grading process, and then switch to the left suction process, it has been circulating continue.
Oxygen workflow is controlled by a programmable controller five two five-way pilot solenoid valve, controlled by a solenoid valve and then were seven pneumatic tube valve opening and closing to complete. Five two five-way pilot solenoid valve control the left suction, pressure equalization, the right suction state. Left suction, pressure equalization, the right time absorbing process has been stored in the programmable controller, in the off state, five two five-way solenoid pilot valve pilot gas valves are turned pneumatic tube closed mouth. When the process is left suction state, control of the left suction solenoid valve is energized, the pilot turned left air suction inlet valve, left suction valve production, the right to open the exhaust valve port, making it a three valve opens, complete the absorption process left , while the right column adsorption and desorption. When the equalizing process in the state, the equalizing control solenoid valve is energized, the other valve is closed; the pilot turned on the gas equalizing valve open mouth, so that the valve is open, complete grading process. When the suction flow in the right state, the right to control the suction solenoid valve is energized, the pilot turned the air sucked into the right valve, the right suction valve production, left open the exhaust valve port, making it a three valves open, the right to complete the absorption process while left adsorber desorption. Each process, in addition to the valves should be opened, other valves should be closed.
4. PSA oxygen system equipment
4.1 Air Compressor
Because PSA separating oxygen from air by pressure adsorption, desorption pressure direct preparation of oxygen from the air, so the air compressor to provide gas compression power source. Currently the main air compressor widely used screw air compressor and piston compressor two categories. Both compressors have their own characteristics, can be used for oxygen generation system. In general, the less wear and tear gas screw compressor, high gas production efficiency, low noise, small amount of maintenance, but compressed air is generally oil, the price is relatively high; the existing piston compressor oil-free and oil lubricating two types of oxygen systems for best supporting the use of oil-free air compressor.
Compressor displacement of oxygen according to specifications. In order not to make the general air compressor has been running at full capacity, there is a certain idle time is conducive to long-term effective use of air compressor, air compressor displacement in the choice of screw air compressor displacement than the general system gas is 10 to 15% oxygen machine requirements than the general requirements for the larger piston compressor displacement of 20 to 25%.
Rated compressor discharge pressure is preferably selected to be 0.5 ~ 0.7Mpa, discharge pressure is too high, too low are bad.
The oil content of the compressed air discharged from the compressor must ≤10ppm w / w, preferable to use oil-free compressor.
PSA oxygen system power consumption is the main equipment of air compressor power consumption.
4.2 Compressed air pretreatment equipment
Because the molecular sieve oxygen Host demanding quality compressed air, compressed air and gas temperature is high, and contains a lot of water and some dust, oil mist, so that the compressed air into oxygen before the host must be in addition to water, oil, dust and other processing equipment in this section is intended primarily for this purpose.
Compressed air purification treatment is essential, this user please do not ignore! Because the quality of compressed air purification process is directly related to the life of molecular sieve, which is directly related to long-term effective use of oxygen. Once the molecular sieve oil "poisoning" oxygen efficiency will decline, unable to reach the normal index.
In addition to the use of compressed air adsorption dryers water main. No heat regeneration adsorption dryer is the use of a renewable desiccant as adsorbent, using pressure changes, gas expansion and other principles, the use of pressure swing adsorption separation process water, compressed air moisture removed.
If you require oxygen dew point is not too low (≤-40 ℃ atmospheric pressure), you do not need adsorption dryer; if desired dew point low oxygen (≤-60 ℃ atmospheric pressure), you need to configure adsorption dryers. It has hot regenerated adsorption dryer and micro-thermal regeneration of two types, both have a certain loss of gas, generally used without heat regeneration dryer.
Compressed air degreasing, dust mainly uses different types of multi-stage precision filtration filter. Filter through activated carbon filter or by a number of microporous fibrous material to remove contaminants medium (water, oil, particulates, odors), all filters have a role in addition to water, oil, dust, but the main function of different filters in different categories. Mainly from the main line filter dust and liquid water in addition to the role; First filter plays a major role in oil; fine filter is a further major oil, medium oil content so little; activated carbon filter oil is mainly from the depth of the inter oil and adsorption of hydrocarbons, in addition to the role of smell. Filter configuration based primarily on the compressor discharge air quality may be. Configuring too little, not fully compressed air purification treatment, oxygen can not reach the quality requirements for compressed air, which is not allowed; configuration too much, although the effect of the compressed air, but will cause the pipeline gas pressure loss is more, but also result in high costs and unnecessary. In general, oil-free air compressor, you need to configure one to two filters, mainly dust, in addition to water; for oil air compressor, you need to configure three to four filters.
      
 Oxygen Host
PSA oxygen host compressed air requirements are as follows:
         Pressure ≥ 0.7Mpa,
         Residual oil content ≤ 0.008PPm,
         Mechanical impurities ≤ 0.01mm
        Pressure dew point ≤ -23 ℃
    Oxygen hosts generally consists of tanks, valves and piping cabinet composed of three parts, specifically including chassis, air buffer tank, oxygen buffer tank, adsorption tower, zeolite molecular sieves, gas distribution system, clamping device, pneumatic pipeline valve, solenoid valve, one-way pipeline valves, filter valves and other valves, PLC controller, high efficiency silencer, oxygen analyzer, flow meters, pressure gauges and other instruments, connecting pipe and other accessories.
2. Working conditions
Ambient temperature: ≤40 ℃
Relative Humidity: ≤65%
Feed air: mechanical impurities: ≤20mg / m3
          CO2 content: ≤250ppm
          C2H2 content: ≤0.5ppm
          CnHm content: ≤20ppm
          Excluding pungent odor and corrosive gases
Power source: 3f380V, 1f220V, 50Hz
 Cooling Water: Water temperature: ≤25 ℃, pH Value: 7-8, total hardness: ≤3.2mmol / L,
             Suspended solids content: ≤100mg / L, the water pressure: ≥0.2Mpa
3. device installation
 Equipment installed by the user is responsible, I am responsible for equipment installation guide.
After all the equipment in place, piping connections between devices based on the actual situation on-site configuration. All lines must be hard-wired (screwed or welded), by construction professionals, in order to avoid leakage phenomenon. Finished with oxygen outlets to
The system will lead to a power supply and cooling water equipment at the scene, ready distribution panels, cooling water supply facilities. Transformer supply facilities.