What should be paid attention to in molecular sieve purification of air separation unit

Molecular sieve purification of air separation unit includes cooling unit stage, liquid accumulation stage and three chamber adjustment stage. In the start-up process, the main focus is to give full play to the refrigeration capacity of the expander, reasonably distribute the cooling capacity and fully cool the unit.

Attention should be paid to the following aspects:

1. The molecular sieve used for the first time should be activated and regenerated once to remove the water and carbon dioxide adsorbed during transportation and filling. The activation temperature is generally higher than 200 ℃ and lower than 250 ℃. When the outlet temperature reaches 80 ℃, it can be cold blown. The activation time is not less than two cycles;

2. When the molecular sieve is started, the air supply process should be slow, and the vent valve should be carefully closed to prevent the molecular sieve in the bed from being damaged due to pressure fluctuation;

3. When the two expanders need to be started, the return valve of the booster should be fully opened to reduce the pressure of the first expander, and then the two expanders should be loaded at the same time to prevent the surge of the later booster;

4. Pay attention to the temperature control in the middle of the heat exchanger;

5. Pay attention to the work of air cooling columnto ensure that the air after precooling meets the design requirements.