Performance evaluation indicators for molecular sieves
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RT, our plant’s liquid nitrogen washing unit uses 5A molecular sieves. I would like to ask what the performance evaluation criteria for molecular sieves are, and how to determine their condition of use.
Specific surface area, bulk density, adsorption capacity
How is adsorption capacity determined? How to determine that a molecular sieve has reached the end of its operational life
Do you mean during operation, or the service life? As for the service life, I found online that it is roughly 5-8 years, but no standard was identified. During operation, the decision is made based on the dew point; for my first attempt, I used the dew point value, and later I reduced the time interval to a more reasonable value.
During operation, we have not encountered any penetration issues yet
“What does “using dew point” mean?
It’s equivalent to specifying a temperature limit for the process; in my case, the required dew point range is < -65°C. When this range is exceeded, it is considered that the drying efficiency has declined, and the tower system needs to be regenerated.
Check whether there is CO2 in the molecular sieve inlet; if so, consider extending the adsorption time of the molecular sieve to estimate its capacity to absorb CO2.