The air separation equipment with an argon tower requires a particularly stable operating condition, as the distribution of argon in the upper tower is not fixed and unchanging. When the purity of oxygen and nitrogen changes, i.e. there is a slight change in operating conditions, the distribution of argon in the tower also changes accordingly. However, the position of the argon fraction extraction port is fixed, so the composition of the argon fraction extraction port will also change.
The change in argon fraction directly affects the argon fraction entering the crude argon tower. When the condensing capacity of the coarse argon tower condenser is constant, the higher the oxygen content in the argon fraction, the more argon fraction enters the coarse argon tower. On the contrary, there are fewer. At the same time, the liquid to gas ratio of the upper tower also changes accordingly. In this way, the working conditions of the crude argon tower are unstable and even unable to work.
How to adjust when the argon fraction changes? When the argon fraction does not meet the requirements and the nitrogen content is too high, the oxygen supply valve can be turned down and the nitrogen discharge valve can be turned up. At this point, the rich argon region in the distillation section rises, and the nitrogen content in the argon fraction decreases; At the same time, the oxygen content increases and the argon content also decreases. When the argon content in the fraction is too low, turning down the liquid nitrogen control valve and improving the nitrogen removal purity can increase the argon content in the fraction. During operation, special attention should be paid to the lifting and lowering of the liquid oxygen surface. The adjustment of oxygen and nitrogen production, as well as the adjustment of air volume, should be carried out slowly and in a timely and appropriate manner, striving for the stability of the liquid oxygen level.
