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PSA Nitrogen Generator Produce High Quality And High-purity Nitrogen
Nov 01, 2017

PSA Nitrogen Generator in the use of the problems encountered in two is more common, one is the reliability is difficult to guarantee, the second is the security problems. Its reliability is difficult to ensure that the specific performance in some of the generator is not enough, nitrogen and hydrogen water content is high and there is a certain degree of corrosion, if the improper operation will be returned to the phenomenon of liquid. The above situation will cause the chromatograph is not easy to stabilize and column effect of chromatographic column reduction, serious can be gas road and chromatographic column scrap, or even lead to the total scrap of the chromatograph. The second is the use of the process of security problems, some PSA Nitrogen Generators in the use of the compressor in the process will produce overheating, gas road into the oil, leakage, and other phenomena, not only to the chromatograph caused damage, serious will endanger the life of the operator safety.

Because the chromatograph uses high-purity nitrogen or high-purity hydrogen to carry gas, in order to deal with the above problems, we have summed up some experiences from three aspects of PSA Nitrogen Generator, nitrogen generator and compressor safety reliability. Air as an auxiliary gas its purity requirements are not high, after dehydration after oil can basically meet the requirements of chromatographic Analyzer, so this article no longer detailed analysis.

First of all, the PSA Nitrogen Generator is mainly composed of electrolysis system, pressure control system, purifying system and display system. Electrolysis using the current membrane separation technology, from the infrared photoelectric feedback device and switching power supply of the pressure control system, so that the occurrence of hydrogen in accordance with the needs of the output automatically adjusted to maintain the output flow and pressure stability. Some of the main problems with hydrogen generated by this principle are:

1. The hydrogen produced by the hydrogenation generator with Koh aqueous solution is high in moisture content and has some corrosive property, which causes the instability of the chromatographic instrument to be debugged, and it is necessary to reduce the column effect of chromatographic column once the hydrogen gas is used for a long time.

2. If the hydrogen gas produced by this principle is used for a long time, it will cause serious reflux phenomenon. In order to prevent the return of liquid, manufacturers designed a variety of devices to try to solve the problem, but can not solve the fundamental problems. After all, it still wants to add liquid, once the backflow of the device failure will cause the gas road and chromatographic column scrap, serious may even lead to gas chromatograph all scrap.

3. Most of the gas purity has not been tested, although the baseline and pillar life can be judged by its purity, the result is to the chromatographic column caused unnecessary loss.

Therefore, hydrogen as an auxiliary gas is also OK, do not carry gas purity. In the selection of PSA Nitrogen Generator priority to ensure the quality of the manufacturers, but also can be installed on-line purity testing device to ensure the purity of the gas.

Secondly, whether the nitrogen generator can be used well in gas chromatographic analysis is very important to the principle of the generator. The working principle of nitrogen generator is roughly divided into three kinds:

1. The combination of electrochemical separation and physical adsorption method

2. The use of hollow fiber membrane separation

3. Separation of new synthetic molecular sieves by gas chromatography

There are a lot of problems with the nitrogen produced by the principle of electrochemical separation and physical adsorption. The main problems are:

1. The nitrogen in the nitrogen generator with KOH aqueous solution has high water content and a certain corrosive effect.

2. There is a phenomenon of reflux.

3. Low purity of nitrogen, the thermal conductivity of the detector of the chromatograph will cause oxidation, a long time the sensitivity of the detector to reduce.

In view of the above three points, many chromatograph manufacturers, instrument distributors and maintenance personnel do not recommend the use of this principle to produce nitrogen generator gas chromatograph.

Nitrogen membrane systems can increase the cost of nitrogen from 78% to more than 95% of the cheap air, with a maximum of 99.9% pure nitrogen. The nitrogen generator can be used in gas chromatograph to carry gas, only suitable for the analysis of the components of the industry with low requirements.

Separation of new synthetic molecular sieves by gas chromatography

This is a new type of air separation method, which is compressed air as raw material, synthetic molecular sieve as adsorbent, gas chromatography separation adsorption process, at ambient temperature and low pressure, the use of oxygen and nitrogen in the air diffusion in molecular sieve, the separation of oxygen and nitrogen, the purity of nitrogen and gas production can be adjusted according to customer needs. The gas flow rate is stable, the nitrogen purification is thorough, the nitrogen purity of the output is high, the highest can obtain 99.9995% pure nitrogen, suitable for various gas chromatograph detectors. The generator can produce high quality and high-purity nitrogen, running stably and reliably without any chemical consumables. Easy to operate, can be unattended for 24 hours. And it can operate without any supervision and minimum maintenance.

To sum up, the nitrogen generator using the separation method of synthetic molecular sieve by gas chromatography is better than that by using the electrochemical separation method and the physical adsorption method and the hollow fiber membrane method. It can be used in various types of gas chromatograph at home and abroad as a carrier gas, is a good performance maintenance of a new generation of nitrogen generator.

Finally, in order to ensure the safe and reliable operation of generator compressor, we need to pay attention to two points:

1, because the compressor is the perceptual load, through the power outage when the instantaneous current is several times higher than normal work, more easily fuse insurance. The start and stop of the compressor will cause interference to the power grid voltage, so the chromatograph and generator must be separated, or through a regulated power supply. There are two kinds of situations in the working process compressor will stop working, one is the compressor temperature too high thermal protection relay start-up, the second is the voltage instability caused by circuit failure. Therefore, in the use of generators not only the environment needs to ensure good ventilation, and the use of regulated power supply appears particularly important.

2, there are some manufacturers use refrigerators to replace the compressor compressors, this practice violates the relevant national security regulations, the use of the process will produce overheating, gas road into the oil, leakage and other phenomena, to the chromatograph caused damage, serious will endanger the lives of operators safety. In the purchase of generators must pay attention to the generator compressor to meet the requirements.

Now excellent generator manufacturers, the production of generator performance has been greatly improved, has been dedicated to 24 hours 365 days of continuous operation of the generator. Generator using multiple generators in parallel mode of gas supply, through the workstation monitoring the status of each generator, and determination of oxygen content, and other ways to monitor the working state of a single generator, and can automatically balance the work load of a single generator, balancing the supply of each generator. Once the monitoring system found that the single generator has not enough purity, low water level failure, the system will automatically stop the generator operation, and the generator load on average to all other generators. After maintenance and repair, the System Monitor generator is in good condition and will be automatically connected to the gas supply. In addition to the special chromatographic needs of high purity gas can not be satisfied, completely replace the cylinder gas supply, and safe and stable, the quality is relatively reliable.