Nitrogen purity issue
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Our company has a PSA1000 vertical nitrogen generation unit, and recently a certain issue has arisen; the cause has not been identified yet. We would appreciate it if experts out there could help analyze what might be causing it. Due to a malfunction in one of the cold dryers used in the previous processing stage, it was not in operation; however, an air micro-heated dryer was in use. As a result, the purity of the nitrogen (with an oxygen content below 20,000 ppm) often failed to meet the required standards. But when the nitrogen was disconnected from the nitrogen pipeline network, its purity became acceptable after a few hours of operation; yet once it was connected back to the network, the purity dropped again. The dew point of the air entering the nitrogen PSA unit was around -13 to -17 degrees Celsius. This is the current situation; please help analyze what the cause might be. The valves of the nitrogen PSA have been checked and are in good condition.
Is there any flow at the nitrogen outlet? Is it overloaded?
It is recommended to use valves to control the flow rate~~
1. Is the intake pressure too low? 2. Fault in the cold dryer; water entered the molecular sieve earlier. 3. Fault in oxygen content analysis. 4. Is the flow rate excessive?
1. Preliminarily, it is judged that moisture has penetrated due to the shutdown of the cold dryer and overload during microheat regeneration. Even if the compressed air source is an oil-injected screw compressor, the high temperature of the compressed air may cause some of the oil to be carried into the molecular sieve. To check the oil content of the molecular sieve. Otherwise, the molecular sieve is at risk of becoming unusable. 2. If the cold dryer is not repaired in time, the purity of nitrogen will continue to decline after it is connected to the network. The regeneration gas flow rate of the PSA equipment should be increased to remove the moisture adsorbed by the carbon molecular sieve. If oil has entered, the molecular sieve should be activated or replaced.
Is there any information on the activation of molecular sieves? You can share it
The activation of carbon molecular sieves must be sent back to the molecular sieve factory for processing