An overview of several nitrogen generators commonly found on the market

Nitrogen generator is a set of nitrogen extraction equipment, it is mainly used in aerospace, nuclear power, food and medicine, petrochemicals, electronics industry, materials industry and scientific experiments and other fields.
in order to facilitate everyone to understand the status quo, I would like to introduce several nitrogen generator principles applied to gas chromatography experiments, for your reference only.
1. A combination of electrochemical separation and physical adsorption 2. Hollow fiber membrane separation method 3. An overview of the gas chromatography column adsorption separation technology, electrochemical separation method and physical adsorption method (requires "liquid addition"): the generator using electrochemical separation method and physical adsorption method can produce pure nitrogen, oxygen and other gases.
It uses a constant-inductive electrolysis method, using a microporous film (e.g. asbestos film) as a dividing plate for two electrodes, a porous gas diffusion type of oxygen electrode is extremely cathode, a nickel mesh is an anode, and electrode installation is a hard support structure.
the generator can work steadily under nitrogen and oxygen chamber pressure differential (1MPa), avoiding cathode hydrogen production and ensuring the purity of nitrogen produced by the gas.
The specific method of producing nitrogen is to feed the gas into an electrolyte-producing electrolyte electrolyte with air as a raw material, adding a voltage of ≤1.5V of direct current between the two electrodes, at which point oxygen is absorbed in the air in the tank and nitrogen is obtained.
the electrolyte is "forced circulation mode", the electrolyte is driven by the electromagnetic pump to circulate in the liquid road, which improves the electrolyte efficiency.
many problems with nitrogen produced by using this principle.
The main problems are: 1. Nitrogen generators with KOH liquid (water) produce high water content and a certain corrosiveness, easy to cause the chromatography debugging instability, once the use of nitrogen for a long time will inevitably lead to a reduction in the efficiency of the column column.
2. Nitrogen produced by this principle can cause a serious rehydration (rehydration) phenomenon if used at normal pressure (standard atmospheric pressure) for a long time.
to prevent rehydration, manufacturers have designed various devices to try to solve this problem, but can not solve the fundamental problem.
After all, it is still to add fluid, once the device failure of anti-rehydration will cause gas road and chromatography column scrap, serious may even lead to gas chromatography all scrap.
3. The low purity of nitrogen causes oxidation of the thermal element of the thermal conductor detector of the chromatography, and the sensitivity of the thermal guide detector is reduced over a period of time.
in view of the existence of the above three points of the problem, many chromatography manufacturers, instrument dealers and maintenance personnel are not recommended to use this principle to produce nitrogen generator to do gas chromatography gas.
II, the use of hollow fiber membrane method (no need to "add fluid"): two or more gases mixed through the polymer membrane, due to the differences in the solubility and diffusion coefficients of various gases in the membrane, resulting in different gases in the membrane relative penetration rate is different.
according to this characteristic, the gas can be divided into "fast" and "slow gas".
When the mixture gas in the driving force --- membrane pressure difference on both sides of the role of the relatively fast penetration rate of gas and water, oxygen, carbon dioxide, etc. through the membrane after the membrane permeation side is rich, and the penetration rate of relatively slow gas such as nitrogen, carbon monoxide, argon, etc. in the residual side is rich, so as to achieve the purpose of gas separation.
when the pressurized purified air as the gas source, nitrogen and other inert gases are rich in integrated high purity for production applications, by the permeable side of the exhaust for oxygen-rich air.
system can increase the inexpensive air nitrogen from 78% to more than 95%, and can obtain 99.9% of the pure nitrogen.
nitrogen generator can be used in gas chromatography to do gas, analysis components are not high requirements of the industry.
3. The use of gas chromatography separation technology (no need to "add liquid"): This is a new air separation method, it is compressed air as raw material, synthetic molecular sieve as an adsorbent, the use of gas chromatography column adsorption process, at room temperature pressure, the use of oxygen and nitrogen in the air in the molecular sieve diffusion speed is different, oxygen and nitrogen separation, nitrogen purity and gas production can be adjusted according to customer needs.
produces a stable gas flow rate, nitrogen purification thoroughly, the output of nitrogen purity is high, high can obtain 99.9995% of pure nitrogen, suitable for a variety of gas chromatography detector.
the series of high purity generators can produce high-quality and high-purity nitrogen at the click of a switch, and are stable and reliable to operate, it is important that it does not require any chemical consumables.
easy to operate and can be left unattended 24 hours a day.
and it can operate without any supervision or maintenance without fault.