The high water level interlock is installed in the air cooling tower of the air separation equipment to prevent the cooling water from being carried by the airflow into subsequent systems (such as molecular sieves, heat exchangers, or compressors) due to high liquid level, which may cause equipment damage, process abnormalities, or even production shutdown. This protection mechanism ensures the safe and stable operation of the system by automatically cutting off the incoming liquid or adjusting the process flow.
To prevent water from entering the subsequent system and protect critical equipment, if the water level in the air cooling tower is too high, the cooling water may be carried into the molecular sieve adsorber or switchable heat exchanger by high-speed airflow, causing water to enter these devices. Water may be brought into the inlet of the air compressor, causing compressor surge (severe airflow pulsation, mechanical vibration and noise), and in severe cases, damaging compressor blades or shaft seals. After water enters the subsequent system, it may trigger a chain reaction, ultimately leading to the forced shutdown of the air separation unit and affecting production continuity.
To avoid exacerbating water level issues due to abnormal pressure, when the pressure in the air cooling tower is too low, the airflow velocity decreases, and the impact and entrainment on the liquid level weaken. However, if the water level is already high at this time, it may actually cause poor cooling water flow due to insufficient pressure, further exacerbating the rise in water level. The high water level interlock usually works in conjunction with the low pressure interlock. When the pressure is too low, the system may increase the pressure or adjust the airflow through interlocking to prevent the water level from losing control due to abnormal pressure; At the same time, the high water level interlock directly responds to the liquid level exceeding the standard, quickly cutting off the source of risk.
To ensure process stability and heat exchange efficiency, the core function of an air cooling tower is to lower the air temperature to the required process value through heat exchange between cooling water and air. In extreme cases, a high water level may submerge the air inlet pipeline, causing airflow obstruction, system pressure fluctuations, and even vacuum damage, posing a threat to the safety of the entire air separation unit.
