Switching purification process what problems should be paid attention to when the air separation plant restarts after a short-term stop?

Switching purification process air separation equipment refers to self-cleaning of moisture and carbon dioxide in the passageway of switching Plate-fin Heat Exchanger (or cooler) through switching valve. Switching purification process the air separation equipment mostly adopts the method of circulation or extraction to reduce the temperature difference of the cold end of the Plate-fin Heat Exchanger (or the cooler); it adopts the expansion heat exchanger to recover the cooling, further reduce the temperature of the expansion gas; use the liquid supercooler to further reduce the liquid temperature of the throttle entering the upper tower. Therefore, when switching purification process air separation plant restarts after short-term parking, attention should be paid:
1) before recovery, determine the start-up circuit according to the temperature recovery situation at the cold end;
2) for the air separation equipment with liquid supercooler, a part of the liquid from the lower tower and the main cooling should be drained before starting to prevent the blocking of the liquid supercooler;
3) when the temperature at the cold end reaches-150℃, the circular flow should be reduced as much as possible to prevent carbon dioxide from blocking the circulation channel;
4) shorten the switching time and reduce the cold end temperature as soon as possible;
5) when the temperature at the cold end reaches the technological requirements and the air separation starts into the fourth stage, the expansion heat exchanger should not be started first to prevent carbon dioxide from blocking the expansion heat exchanger.