The molecular sieve purification system is the key purification unit of the air separation unit. Once a water inflow accident occurs, the molecular sieve adsorption failure and chalking hardening will be caused, which not only shortens the service life of consumables, but also causes water entrainment and heat exchange blockage in the cold box, and seriously affects the safe and stable operation of the air separation equipment. In combination with the production conditions, it is necessary to prevent water ingress from equipment, operation, operation and maintenance.
First, strictly control the front-end cooling system, which is the main source of water inflow. Regularly check the packing and water distributor of the air cooling tower to eliminate spray deflection and entrainment of steam and water; Strictly control the pressure and liquid level of cooling water to prevent water from entering the tower due to ultra-high liquid level. Meanwhile, ensure the temperature control stability of the chiller unit to avoid air precipitation of condensed water.
Secondly, regulate manual operation and procedure control. The startup and shutdown of the unit shall strictly follow the pressure rise and drop rate, and fast pressure relief is prohibited to cause water entrainment of airflow vortex; In the process of molecular sieve switching, control the action rhythm of the valve, and strictly prevent water backflow caused by internal leakage of the valve. Check the drain valve and blow-off valve daily to ensure smooth automatic drainage and timely discharge the residual condensate water in the pipeline.
Finally, patrol inspection and maintenance shall be strengthened. Focus on monitoring the aftercooler of air compressor and pipeline heat tracing equipment, and eliminate pipeline leakage hazards; Regularly check the working condition of molecular sieve and timely handle the caking caused by damp. Through the source control, standard operation and regular inspection, the water inflow accident of the purification system is completely eradicated to ensure the long-term stable operation of the air separation unit.
