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PSA Nitrogen Generator Easy To Maintain
Jul 01, 2017

PSA Nitrogen Generator is an advanced gas separation technology, high-quality imported carbon molecular sieve (CMS) as adsorbent, using pressure swing adsorption at room temperature (PSA) separation of air to produce high purity nitrogen.

Oxygen and nitrogen have different diffusion rates on the surface of molecular sieves. The smaller diffusion rate of gas molecules (O2) is faster, and the diffusion rate of gas molecules (N2) Slow, into the carbon molecular sieve pores less. The use of carbon molecular sieves for the selective adsorption of nitrogen and oxygen differences, resulting in a short time in the adsorption of oxygen in the adsorption phase, nitrogen enrichment in the gas phase, such as oxygen and nitrogen separation, in the PSA conditions to get gas phase nitrogen.

Carbon molecular sieve on the oxygen and nitrogen at different pressures at a certain time the amount of adsorption changes in the curve:

After a period of time, the adsorption of oxygen on the molecular sieve to balance, according to carbon molecular sieve at different pressures on the adsorbed gas adsorption capacity of different characteristics, reduce the pressure of carbon molecular sieve to remove the adsorption of oxygen, the process for regeneration. According to the different regeneration pressure, can be divided into vacuum regeneration and atmospheric regeneration. Atmospheric regeneration is conducive to the complete regeneration of molecular sieve, easy to obtain high purity gas.

PSA Nitrogen Generator is a set of equipment to extract nitrogen, its main application areas are: aerospace, nuclear nuclear energy, food and medicine, petrochemical, electronics industry, materials industry, national defense and scientific experiments and other fields. In order to understand the status quo, the following I have introduced several applications in the gas chromatography analysis of PSA Nitrogen Generator principle, for your reference.

1, electrochemical method of nitrogen;

2, using hollow fiber membrane separation method;

3, PSA pressure swing adsorption nitrogen.

The use of electrochemical method of PSA Nitrogen Generator can be made of pure nitrogen, oxygen and other gases. It uses a constant potential electrolysis method, the use of microporous membrane (such as asbestos film) as the separation of the two electrodes, porous gas diffusion electrode for the cathode, nickel mesh for the anode, and the electrode is installed using a hard support structure. The generator can be nitrogen, oxygen chamber pressure (1MPa) under the stable operation, to avoid cathodic hydrogen precipitation, to ensure the purity of nitrogen gas. The specific method of making nitrogen is to feed the gas into the electrolytic cell with air as the raw material. Between the two electrodes, the DC voltage of ≤ 1.5V is added, and oxygen is absorbed in the air in the tank to obtain nitrogen. The electrolyte with "forced circulation", driven by the electromagnetic pump electrolyte in the liquid circulation, improve the electrolysis efficiency.

This method can produce up to 99.995% of the nitrogen, but there are several obvious defects: First, the need to use a high concentration of potassium hydroxide solution as electrolyte, this strong alkali solution and gas in direct contact with the gas quality The second part of the unit cost is high, not suitable for large flow of PSA Nitrogen Generator; Third, the reaction process only to remove the oxygen in the air, other impurities are not involved in the gas, and the other The reaction process of the electrolytic cell production technology requirements are high, inappropriate electrolytic cell production technology will result in the order of nitrogen purity reduction. However, such PSA Nitrogen Generators, as a source of small flow nitrogen, are often used for chromatographic carrier gas and small capacity protection, the total cost of a few thousand dollars, is a low-cost solution.

When two or more gases are mixed through the polymer membrane, the relative permeation rates of the different gases in the membrane are different due to the difference in solubility and diffusion coefficient of the various gases in the membrane. According to this feature, the gas can be divided into "fast" and "slow gas".

When the mixed gas in the driving force - both sides of the pressure on both sides of the membrane under the action of a relatively rapid penetration rate of gas and water, oxygen, carbon dioxide and other membrane through the membrane after the infiltration side is enriched, and the infiltration rate is relatively slow Gas such as nitrogen, carbon monoxide, argon, etc. are concentrated in the retention side, so as to achieve the purpose of mixed gas separation.

When pressurized air is used as the gas source, inert gases such as nitrogen are enriched into high purity for production applications, and oxygen-enriched air is emptied from the permeate side. Nitrogen film system can be low in the air from 78% to 95%, up to 99.9% of pure nitrogen.

This method of nitrogen separation of membrane nitrogen in the industry has a lot of applications in the laboratory is mainly used for gas purity requirements are not particularly high purging, protection, replacement of oxygen and so on. The main advantages of this type of generator is the flow of large, while long life, and maintenance costs are very low; the disadvantage is that nitrogen purity can not achieve high purity, membrane components are currently imported, domestic can not provide high cost, instrument prices are relatively high.

The use of nitrogen and other gas molecules in the molecular sieve adsorption capacity difference, the formation of the concentration of the accumulation of different concentrations in the molecular sieve column output of high purity nitrogen. At the same time the use of two molecular sieve column, a suction at the same time leads to a part of the product gas for another analysis, to achieve molecular sieve online regeneration, the overall performance of the instrument is the continuous output of high purity nitrogen.

This type of generator can adjust the purity and flow rate of nitrogen according to the need, the maximum production of 99.999% of the nitrogen product, the flow can be from several hundred milliliters to tens of liters to several cubic feet per minute, the purity of the configuration flexibility, according to each demand Customized for a wide range of gas chromatograph detectors.

As described above, the PSA Nitrogen Generator using the PSA pressure swing adsorption nitrogen technology is superior to the PSA Nitrogen Generator using the electrochemical separation method and the physical adsorption method and the hollow fiber membrane method. It can be used at home and abroad for a variety of different types of gas chromatograph used as a carrier gas, is a good performance, easy maintenance of a new generation of PSA Nitrogen Generator, with the world's leading level.