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There are two common problems encountered in the use of gas generators, one is that the reliability is difficult to guarantee, and the other is that there are problems with safety
.
Its reliability is difficult to guarantee.
The specific performance is that the purity of some generators is not enough, the water content in nitrogen and hydrogen is high, and it is also corrosive to a certain extent.
If the operation is improper, there will be liquid backflow
.
The above situation will make the chromatograph not easy to stabilize and the column efficiency of the chromatographic column will be reduced.
In severe cases, the gas path and the chromatographic column may be scrapped, and even the chromatograph will be scrapped
.
Secondly, there are safety problems during use.
Some compressors of gas generators will overheat, oil in the gas path, and electricity leakage during use, which will not only cause damage to the chromatograph, but also endanger the operator in severe cases.
life safety
.
Because the chromatograph uses high-purity nitrogen or high-purity hydrogen as the carrier gas, in order to deal with the above problems, we have summarized some experiences from three aspects of the safety and reliability of the hydrogen generator, nitrogen generator and compressor for your reference
.
Air as an auxiliary gas does not require high purity, and it can basically meet the analysis requirements of chromatograph after dehydration and oil removal, so this article will not analyze it in detail
.
The hydrogen generator is mainly composed of electrolysis system, pressure control system, purification system and display system
.
The electrolysis adopts the current membrane separation technology and a pressure control system composed of an infrared photoelectric feedback device and a switching power supply, so that the amount of hydrogen generated is automatically adjusted according to the output needs, and the output flow and pressure are kept stable
.
The main problems of hydrogen produced by this principle are: 1.
The hydrogen generated by the hydrogen generator with KOH aqueous solution has high water content and certain corrosiveness, which is easy to cause unstable debugging of the chromatograph.
Once used for a long time The hydrogen used as the carrier gas will inevitably reduce the column efficiency of the chromatographic column
.
2.
If the hydrogen produced by this principle is used for a long time, it will cause serious liquid return phenomenon
.
In order to prevent liquid backflow, manufacturers have designed various devices to try to solve this problem, but none of them can solve the fundamental problem
.
After all, it still needs to be added liquid.
Once the anti-liquid return device fails, the gas path and the chromatographic column will be scrapped, and even the gas chromatograph may be completely scrapped
.
3.
The purity of the gas is mostly untested.
Although the purity can be judged by the baseline and the service life of the column, the result is unnecessary loss to the chromatographic column
.
Therefore, hydrogen can be used as an auxiliary gas, but the purity of the carrier gas is not enough
.
When choosing a hydrogen generator, priority is given to manufacturers with guaranteed quality, and an online purity detection device can also be installed to ensure the purity of the gas
.
Secondly, whether the nitrogen generator can be well used in gas chromatography analysis experiments has a lot to do with the principle of the generator
.
The working principle of nitrogen generator is roughly divided into three types: 1.
Combining electrochemical separation method and physical adsorption method 2.
Using hollow fiber membrane separation 3.
Using gas chromatography technology to separate by new synthetic molecular sieve 1.
Electrochemical separation method And physical adsorption method: There are many problems with nitrogen produced by this principle
.
The main problems are: 1.
The nitrogen produced by the nitrogen generator with KOH aqueous solution has high water content and certain corrosiveness
.
2.
There is a phenomenon of backflow
.
3.
The purity of nitrogen gas is low, which will cause oxidation to the thermal element of the thermal conductivity detector of the chromatograph, and the sensitivity of the thermal conductivity detector will decrease over time
.
In view of the above three problems, many chromatograph manufacturers, instrument dealers and maintenance personnel do not recommend using this principle to generate nitrogen generators as carrier gas for gas chromatographs
.
2.
Using hollow fiber membrane method: The nitrogen membrane system can increase the cheap nitrogen in the air from 78% to more than 95%, and the high one can get 99.
9% pure nitrogen
.
This nitrogen generator can be used as a carrier gas for gas chromatographs, and is only suitable for industries with low requirements for analyzing components
.
3.
Separation with a new type of synthetic molecular sieve by gas chromatography technology: This is a new type of air separation method.
It uses compressed air as raw material, synthetic molecular sieve as adsorbent, and gas chromatography separation and adsorption process.
Oxygen and nitrogen have different diffusion rates in molecular sieves.
To separate oxygen and nitrogen, the purity and gas production of nitrogen can be adjusted according to customer needs
.
The flow rate of the generated gas is stable, the nitrogen is thoroughly purified, and the nitrogen produced is of high purity.
The high purity nitrogen can be obtained at 99.
9995%, which is suitable for various gas chromatography detectors
.
The generator can produce high quality and high purity nitrogen with stable and reliable operation without any chemical consumables
.
It is easy to operate and can be unattended 24 hours a day
.
And it can run trouble-free without any supervision and with minimal maintenance
.
To sum up, the nitrogen generator using the gas chromatography separation technology and the synthetic molecular sieve separation method is superior to the nitrogen generator using the electrochemical separation method, the physical adsorption method and the hollow fiber membrane method
.
It can be used as carrier gas in various types of gas chromatographs at home and abroad, and is a new generation nitrogen generator with excellent performance and easy maintenance
.
Finally, in order to ensure the safe and reliable operation of the generator compressor, it is necessary to pay attention to two points: 1.
Because the compressor is an inductive load, the instantaneous current during power-on and power-off is several times higher than that during normal operation, and it is easier to fuse the insurance
.
The start and stop of the compressor will interfere with the grid voltage, so the power supply of the chromatograph and the generator must be separated or supplied through a regulated power supply
.
There are two situations in the working process that the compressor will stop working.
One is that the compressor temperature is too high and the thermal protection relay is activated, and the other is that the voltage is unstable and the circuit is faulty
.
Therefore, when using the generator, not only the environment needs to ensure good ventilation, but also it is particularly important to use a regulated power supply for power supply
.
2.
Some manufacturers use refrigerator compressors instead of air compressors.
This practice violates relevant national safety regulations.
During the use process, phenomena such as overheating, oil entering the gas path, and electricity leakage will occur, which will cause damage to the chromatograph and cause serious damage.
will endanger the life of the operator
.
When purchasing a generator, you must pay attention to whether the compressor of the generator meets the requirements
.
.
Its reliability is difficult to guarantee.
The specific performance is that the purity of some generators is not enough, the water content in nitrogen and hydrogen is high, and it is also corrosive to a certain extent.
If the operation is improper, there will be liquid backflow
.
The above situation will make the chromatograph not easy to stabilize and the column efficiency of the chromatographic column will be reduced.
In severe cases, the gas path and the chromatographic column may be scrapped, and even the chromatograph will be scrapped
.
Secondly, there are safety problems during use.
Some compressors of gas generators will overheat, oil in the gas path, and electricity leakage during use, which will not only cause damage to the chromatograph, but also endanger the operator in severe cases.
life safety
.
Because the chromatograph uses high-purity nitrogen or high-purity hydrogen as the carrier gas, in order to deal with the above problems, we have summarized some experiences from three aspects of the safety and reliability of the hydrogen generator, nitrogen generator and compressor for your reference
.
Air as an auxiliary gas does not require high purity, and it can basically meet the analysis requirements of chromatograph after dehydration and oil removal, so this article will not analyze it in detail
.
The hydrogen generator is mainly composed of electrolysis system, pressure control system, purification system and display system
.
The electrolysis adopts the current membrane separation technology and a pressure control system composed of an infrared photoelectric feedback device and a switching power supply, so that the amount of hydrogen generated is automatically adjusted according to the output needs, and the output flow and pressure are kept stable
.
The main problems of hydrogen produced by this principle are: 1.
The hydrogen generated by the hydrogen generator with KOH aqueous solution has high water content and certain corrosiveness, which is easy to cause unstable debugging of the chromatograph.
Once used for a long time The hydrogen used as the carrier gas will inevitably reduce the column efficiency of the chromatographic column
.
2.
If the hydrogen produced by this principle is used for a long time, it will cause serious liquid return phenomenon
.
In order to prevent liquid backflow, manufacturers have designed various devices to try to solve this problem, but none of them can solve the fundamental problem
.
After all, it still needs to be added liquid.
Once the anti-liquid return device fails, the gas path and the chromatographic column will be scrapped, and even the gas chromatograph may be completely scrapped
.
3.
The purity of the gas is mostly untested.
Although the purity can be judged by the baseline and the service life of the column, the result is unnecessary loss to the chromatographic column
.
Therefore, hydrogen can be used as an auxiliary gas, but the purity of the carrier gas is not enough
.
When choosing a hydrogen generator, priority is given to manufacturers with guaranteed quality, and an online purity detection device can also be installed to ensure the purity of the gas
.
Secondly, whether the nitrogen generator can be well used in gas chromatography analysis experiments has a lot to do with the principle of the generator
.
The working principle of nitrogen generator is roughly divided into three types: 1.
Combining electrochemical separation method and physical adsorption method 2.
Using hollow fiber membrane separation 3.
Using gas chromatography technology to separate by new synthetic molecular sieve 1.
Electrochemical separation method And physical adsorption method: There are many problems with nitrogen produced by this principle
.
The main problems are: 1.
The nitrogen produced by the nitrogen generator with KOH aqueous solution has high water content and certain corrosiveness
.
2.
There is a phenomenon of backflow
.
3.
The purity of nitrogen gas is low, which will cause oxidation to the thermal element of the thermal conductivity detector of the chromatograph, and the sensitivity of the thermal conductivity detector will decrease over time
.
In view of the above three problems, many chromatograph manufacturers, instrument dealers and maintenance personnel do not recommend using this principle to generate nitrogen generators as carrier gas for gas chromatographs
.
2.
Using hollow fiber membrane method: The nitrogen membrane system can increase the cheap nitrogen in the air from 78% to more than 95%, and the high one can get 99.
9% pure nitrogen
.
This nitrogen generator can be used as a carrier gas for gas chromatographs, and is only suitable for industries with low requirements for analyzing components
.
3.
Separation with a new type of synthetic molecular sieve by gas chromatography technology: This is a new type of air separation method.
It uses compressed air as raw material, synthetic molecular sieve as adsorbent, and gas chromatography separation and adsorption process.
Oxygen and nitrogen have different diffusion rates in molecular sieves.
To separate oxygen and nitrogen, the purity and gas production of nitrogen can be adjusted according to customer needs
.
The flow rate of the generated gas is stable, the nitrogen is thoroughly purified, and the nitrogen produced is of high purity.
The high purity nitrogen can be obtained at 99.
9995%, which is suitable for various gas chromatography detectors
.
The generator can produce high quality and high purity nitrogen with stable and reliable operation without any chemical consumables
.
It is easy to operate and can be unattended 24 hours a day
.
And it can run trouble-free without any supervision and with minimal maintenance
.
To sum up, the nitrogen generator using the gas chromatography separation technology and the synthetic molecular sieve separation method is superior to the nitrogen generator using the electrochemical separation method, the physical adsorption method and the hollow fiber membrane method
.
It can be used as carrier gas in various types of gas chromatographs at home and abroad, and is a new generation nitrogen generator with excellent performance and easy maintenance
.
Finally, in order to ensure the safe and reliable operation of the generator compressor, it is necessary to pay attention to two points: 1.
Because the compressor is an inductive load, the instantaneous current during power-on and power-off is several times higher than that during normal operation, and it is easier to fuse the insurance
.
The start and stop of the compressor will interfere with the grid voltage, so the power supply of the chromatograph and the generator must be separated or supplied through a regulated power supply
.
There are two situations in the working process that the compressor will stop working.
One is that the compressor temperature is too high and the thermal protection relay is activated, and the other is that the voltage is unstable and the circuit is faulty
.
Therefore, when using the generator, not only the environment needs to ensure good ventilation, but also it is particularly important to use a regulated power supply for power supply
.
2.
Some manufacturers use refrigerator compressors instead of air compressors.
This practice violates relevant national safety regulations.
During the use process, phenomena such as overheating, oil entering the gas path, and electricity leakage will occur, which will cause damage to the chromatograph and cause serious damage.
will endanger the life of the operator
.
When purchasing a generator, you must pay attention to whether the compressor of the generator meets the requirements
.
