In the normal operation of the crude argon Tower, sometimes the resistance drop, the argon content drop and the oxygen content increase of the crude argon tower will happen suddenly, and the normal operation condition of the crude argon tower will be destroyed, it is called "nitrogen plug" working condition of crude argon tower. The direct reason for the "nitrogen plug" of the crude argon Tower is that the nitrogen content of the argon distillation in the upper tower exceeds, and generally the nitrogen content should not exceed 0.1%. This is because the separation of oxygen and argon is conducted in the crude argon Tower, and most of the oxygen in the argon distillation is condensed in the rising process, while the nitrogen component of low boiling point is not condensed, and all of them are left in the crude argon, making the nitrogen content in the crude argon be dozens of times larger than that in the argon distillation.
The heat transfer temperature difference of the crude argon Tower condenser is generally designed according to the nitrogen content of the crude argon which is 1.5%. If the content of the crude argon increases greatly, the temperature difference of the crude argon Tower condenser will be reduced, or even zero, in this way, the condensation of crude argon decreases or even does not condense, which will reduce the extraction of argon distillation and lower the flow rate of rising gas, causing leakage of the tower plate and finally leading to the failure of the crude argon tower to work normally. Once the "nitrogen plug" of the crude argon tower occurs, the blowing-off valve on the crude argon pipeline should be opened quickly first, so that the nitrogen gathered on the condensing side of the condenser of the crude argon tower can be discharged into the atmosphere quickly, then adjust the operating condition of the upper tower to make the nitrogen content of argon fraction gradually return to normal condition, and re-establish the crude argon column to return to normal rectification condition.
