Discussion on the operation of the air separation liquid accumulation purification valve
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Hello, masters. When the main coolant level exceeds 2000 mm and the process shifts from liquid accumulation to purification, how should V6 (liquid nitrogen return valve to the lower column) and HV1 (throttle valve for liquid nitrogen going to the upper column) be operated to facilitate liquid accumulation and purification and reduce the time required?
The degree of opening of the two valves directly affects the thermal load of the condensation evaporator; when liquid accumulates, it is necessary to keep the thermal load of the condensation evaporator as low as possible. To adjust the purity, first adjust the liquid nitrogen reflux valve in the lower column in order to modify the purity of that column; the specific opening degree should be set based on the resistance in the lower column. Once the conditions in the lower column are satisfactory, then adjust the liquid nitrogen throttle valve in the upper column.
At the end of the liquid accumulation phase, the valve for returning liquid nitrogen to the lower tower should be opened first; the valve for returning liquid nitrogen to the upper tower is used to adjust the purity of that tower. If the adjustments are made too aggressively or too quickly, it can lead to an increase in the air flow into the lower tower, resulting in overpressure in the upper tower.
The reflux can be initiated in stages, slowly. At first, the pressure and resistance in the system change significantly; once the level of the main cooling liquid becomes relatively stable, the reflux can continue； The liquid nitrogen valve at the top of the tower is difficult to open fully, which reduces the cooling load