DEAR Air separation unit.The overall heating procedure in cold state is shutdown - liquid discharge - standing - cold blowing - heating - system blowing. The end point of heating is until the outlet temperature of heating gas reaches normal temperature. The overall heating operation procedure in hot state is divided into two steps: heating and blowing. In order to completely remove the moisture and achieve the purpose of drying, the outlet temperature of heating gas should be higher than normal temperature. In order to remove solid impurities, the blowing out process is more important in the overall heating operation under hot state.Carbon dioxide precipitation stage. In this stage, only the switching heat exchanger is cryogenic to freeze the carbon dioxide in the heat exchanger, which is carried out by the low-pressure backflow gas until the cold end temperature reaches - 170 ℃; in the fourth stage, the purified low-temperature gas is used to further cool other equipment until liquid accumulates in the tower, and then the distillation condition is further adjusted.
DEAR Air separation unit.The heat capacity of the plate fin heat exchanger is small, and the start-up time of the air separation unit is short, at the level of 30-36 h; the start-up time of the air separation unit with the stone cold accumulator is 48-60 H. As far as operation is concerned, it is necessary to master the operation essentials: prevent moisture and carbon dioxide from entering the tower; strictly control the temperature difference between the cold end and the hot end; pay attention to the cooling of the main cooler; strictly control the temperature difference between the cold end and the hot end;The argon fraction is separated from oxygen and argon in a crude argon column. The argon fraction enters from the bottom and crude argon containing about 95% argon is obtained from the top. Because the boiling points of oxygen and argon are close to each other, it is difficult to separate them. About two thirds of argon is washed down.When the boiling point difference between rare gases and impurities is large, the method of segregation can be used to separate them. For example, nitrogen can be separated from neon and helium to obtain crude neon and helium.
DEAR Air separation unit.The refrigerating capacity provided by the refrigerator is usually precooled by the low-temperature working medium of the refrigerator in the air separation unit purified by molecular sieve, so as to improve the adsorption purification effect. This is the cooling capacity provided by the outside of the air separation unit, which refers to the heat carried away by the chilled water from the air. It can reduce the required throttling effect and the cooling capacity of the expander.DEAR Air separation unit.Check and confirm the opening and closing status of the equipment valves for interlock shutdown; check and confirm the alarm interlock items of the air separation unit. Recheck and confirm the interlock control that fails in case of power failure; start the air compressor and air precooling system according to the regulations; start the molecular sieve adsorber according to the regulations.DEAR Air separation unit.When measuring the pressure of piston compressor and similar equipment, shock absorber must be added in the pipeline to prevent the damage of pressure gauge components. Shock absorber usually uses buffer vessel with orifice, or directly uses needle valve instead of globe valve.
