Nitrogen generator fault judgment

Nitrogen generator fault to judge nitrogen generator variable pressure adsorption empty sub-nitrogen (P.S.A nitrogen) is a gas separation technology, with imported carbon molecular sieve (CMS) as an adsorbent, using the principle of variable pressure adsorption (PSA) at room temperature to separate air to obtain high purity nitrogen.
Oxygen, nitrogen two gas molecules on the molecular screen surface diffusion rate is different, the diameter of smaller gas molecules (O2) diffusion rate is faster, more into the carbon molecule sieve micropores, the diameter of the larger gas molecules (N2) diffusion rate is slower, into the carbon molecule sieve micropores less.
the use of carbon molecular sieve on nitrogen and oxygen of this choice adsorption difference, resulting in a short period of time oxygen in adsorption phase abundance, nitrogen in gas phase concentration, so oxygen nitrogen separation, under PSA conditions to obtain gas phase rich nitrogen.
Carbon molecular sieve oxygen and nitrogen at different pressures at a certain time the difference curve of adsorption: First, after the nitrogen generator period, the molecular sieve adsorption of oxygen reached balance, according to the carbon molecular sieve at different pressures on the adsorption of adsorption of gas different characteristics, reduce the pressure so that carbon molecule sieve to remove the adsorption of oxygen, this process is regeneration.
can be divided into vacuum regeneration and normal pressure regeneration according to the regeneration pressure.
normal pressure regeneration is good for the complete regeneration of molecular sieve, easy to obtain high purity gas.
nitrogen generator (PSA nitrogen machine) is a nitrogen production device designed and manufactured according to variable pressure adsorption technology.
Usually using two adsorption towers in a union, by the fully automatic control system according to a specific nitrogen generator can be programmed to strictly control the timing, alternating pressure adsorption and decompression regeneration, complete nitrogen-oxygen separation, to obtain the required high purity of nitrogen.
of the dynamic adsorption and separation coefficient of carbon molecular sieve (CMS) determines the quality of the nitrogen machine.
II, nitrogen generator niobium catalyst deoxygenation process principle flow, purity of universal nitrogen and hydrogen nitrogen generator gas into the device at the same time, after a full mixing in the mixer, into a device equipped with niobium catalyst deoxygenator, under the action of deoxygenation catalyst to produce a chemical reaction of 2H2 plus O2, 2H2O, to achieve deoxygenation purposes.
Nitrogen generator deoxygenation of nitrogen in the water through the cooler dehydration, and then nitrogen continues to dry into the dryer, so that nitrogen dew point of about -60 degrees C, dryer configuration of two, one dryer for adsorption drying, the other has adsorbed saturated water dryer for regeneration, ready for the next cycle of adsorption work.
after the dry nitrogen through the filter dusting, the result is high purity nitrogen.
nitrogen generator uses material and gas chromatography separation technology to extract pure nitrogen directly from the air.
it is a purely physical separation method, eliminating the hidden dangers of electrochemical (watering) separation method corrosion instruments, with the advantages of safe use, reliable performance, long life and so on.
built-in compression pump can continuously output nitrogen for 24 hours, do not need to be accessed from the outside air, with the advantages of safe and convenient use, long life, high reliability, simple operation and so on so that the performance indicators of the gas generator, product quality is more uneven.
below only on the market commonly used three gas generators (hydrogen generator nitrogen generator, air compressor) structure, characteristics to do a simple analysis, for your reference: a nitrogen generator nitrogen generator from the principle of nitrogen production has a hollow fiber membrane separation method, variable pressure adsorption method, electrochemical separation method three.
1) The nitrogen purity directly produced by hollow fiber membrane separation method is generally about 99%, the flow range is 0-10 liters/min, and the market price is about tens of thousands to hundreds of thousands.
2) variable pressure adsorption method directly produces a wider range of nitrogen flow, purity is generally 99%, the market price is about 100,000 or less.
3) The nitrogen flow directly generated by electrochemical separation method is 0.3-0.5L/min, the oxygen content can be controlled in several ppm, and the gas dew point can reach -55 degrees C according to the adsorption agent efficacy.
price is about 10,000.
current domestic supporting gas chromatography nitrogen generator is mainly this type.
of electrochemical separation is derived from the electrolytic separation pool, where impurities in the air are separated by electrolytes and precious metals and electric field.
ionization pool electrolyte is mainly KOH or NaOH and distilled water preparation, some manufacturers in order to reduce manufacturing costs, the use of low-cost low-quality stainless steel, resulting in ionization pool is very easy to damage, and reduce the purity of nitrogen, affecting the normal use of the instrument.
At the same time, electrochemical separation method to produce nitrogen also requires the entire system to have a perfect pressure control, otherwise in the sudden power failure, the electrolyte separation pool does not have the role of electric field, air can not be separated, the output will be a large amount of air, if not timely shut down nitrogen output, a large amount of air directly into the column will cause early damage to the column.
so adding a power-off protection switch valve to the nitrogen output path is yes.
The nitrogen generators on the market generally have the function of starting delay draining, that is, nitrogen generators in just 10 minutes, due to low gas purity and air in the pipeline system, so the output gas needs to be discharged into the atmosphere.
exhaust air body flow control, most manufacturers are used in the drain valve exit plus fixed gas resistance, this method in the process of emptying, you can control the output of the gas flow, but the exhaust end, nitrogen switch to the chromatography gas road, due to the output of nitrogen to Soon in the connected line to establish pressure, so will make the nitrogen generator output flow quickly increased, electrolyte separation pool in a short period of time not to quickly separate air, so that a large number of unresisted air directly into the chromatography system, resulting in column damage or deoxygenation tube quickly failed.
Some manufacturers in front of the emptying port to increase the needle valve to limit flow, this method will have another problem, when the nitrogen system from the exhaust to the normal gas supply state, because the column pressure of the chromatography gradually increased and stabilized, the output flow of the nitrogen generator needle valve will slowly become smaller, if you want to get normal flow need to adjust the needle valve diameter again, so that the stable high purity nitrogen system is contaminated again, we use a large number of experiments, the use of limited flow.
Our company now introduced the nitrogen generator using a large capacity reservoir (8L), effectively reduce the operating temperature of the electrolyte separation pool at work, reduce the humidity of the output gas, extend the life of the electrolyte separation pool, but also reduce the user's daily maintenance workload, but also better solve the nitrogen generator electrolyte separation pool blockage and electrolyte rehydration and other issues.