The reason for water entering the molecular sieve of the air separation equipment is that the operation of the air cooling tower is out of control, and the liquid level is too high. When the liquid level of the air cooling tower exceeds 3500mm, water may flow back into the air inlet pipe. When the resistance exceeds 7kPa, a liquid suspension is formed inside the tower, and the fluctuation of the bottom water level causes water to enter the molecular sieve with the airflow. Excessive spray volume, excessive water spray volume, or malfunctioning automatic water level adjustment can exacerbate gas-liquid entrainment. The program switching is chaotic, and when the molecular sieve switches, the air suddenly empties, causing an increase in gas flow rate in the air cooling tower and carrying moisture. The decrease in instrument air pressure resulted in the failure of pneumatic valve self adjustment and abnormal increase in water level. Poor sealing of the switching valve or leakage of the steam heating tube can introduce moisture. The driving sequence is incorrect, starting the water pump first and then ventilating, or failing to blow off the drain valve before manually inflating. Incomplete regeneration, insufficient heating and cold blowing time, and incomplete removal of residual moisture. The separation efficiency is affected by improper water quality management, circulating water containing foam, unsuccessful dosing or scale accumulation.
Measures to prevent water from entering the molecular sieve include temperature control, ensuring the outlet air temperature of the air cooling tower, and reducing water carryover. Liquid level interlock, installation of liquid level alarm device, automatic drainage and shutdown when the liquid level is too high. Install a water trap at the top of the air cooling tower to enhance gas-liquid separation. Adopting spiral separator or built-in water separator to reduce mist entrainment. Install a drain valve at the lowest point of the air pipe entering the tower and regularly check the drainage situation. Select a dual sealed switching valve and conduct monthly helium leak testing. Standardize operating procedures, driving sequence, regeneration control, and online monitoring.
