Air separation recovery

When the power supply of the air separation unit of the molecular sieve adsorption purification process is resumed after the power failure, the operation should be conducted according to the following steps: 1) the possible influence on the mechanical equipment such as the air compressor when the power is suddenly cut off should be judged. If there is no influence, start-up preparation of the air compressor according to the operation specification of the air compressor; 2) check and confirm the switch state of the chain shutdown equipment valve; 3) check and confirm the alarm chain project of the air separation plant. Re-check and confirm the chain control of failure during power failure; 4) start the air compressor and air precooling system according to regulations; 5) start the molecular sieve adsorber according to regulations. Continue to complete the process before shutdown. If the downtime is long (more than 24 hours), the molecular sieve adsorber should recycle for one cycle; ...

A user of DEAR air separation reflected that when the air separation plant was put into operation, a large liquid nitrogen storage tank was equipped for emergency backup when the air separation was stopped or export of liquid products. The value of oxygen content in nitrogen product is designed to be less than 3ppm (i.e., < 3 ×10-6) due to the high requirement of users for nitrogen purity. But in fact, the oxygen content of liquid nitrogen in the tanks had been found more than 5ppm. The substandard purity of liquid nitrogen not only affects the export of products, but also directly affects the emergency backup of liquid nitrogen backup system.