What factors affect the argon content in the argon fraction?

There are many factors that affect the argon fraction. The level of the main cooling liquid, the pressure at the exit of the air compressor, which is also the pressure in the lower column; the yield of nitrogen and oxygen; the purity of the gas in the lower column; the liquid level in the second column for crude argon; the liquid level in the upper column; the amount of oxygen that is vented into the dirty nitrogen pipeline; and the amount of argon drawn from the refined argon column – all of these factors have an impact on the argon fraction. In short, any factor that can cause changes in the reflux ratio of the upper column will also lead to changes in the argon fraction.

⒈ Changes in oxygen production have a significant impact on the argon fraction; a 0.1% change in oxygen purity results in a 0.8%–1% change in the oxygen content of the argon fraction. The amounts of argon and nitrogen in the argon fraction increase as oxygen purity decreases. Changes in nitrogen production also have a certain effect on the argon fraction, though to a relatively minor extent; reducing nitrogen production leads to a slight increase in the nitrogen content in the argon fraction. ⒉ The amount of expansion increases or decreases; as the oxygen purity decreases or increases, the amounts of nitrogen and argon in the argon fraction also increase or decrease. ⒊ When the automatic adjustment of the throttling valve in the upper tower is unstable and subject to large fluctuations, the argon fraction will also fluctuate accordingly. When the valve is opened wider, the concentrations of argon and nitrogen in the argon fraction increase; conversely, these concentrations decrease. ⒋ When the automatic adjustment of the liquid-air throttle valve in the crude argon column condenser is unstable and experiences large fluctuations, it will also affect the argon fraction. When this valve is closed, the liquid air throttle valve leading to the upper column opens, resulting in an increase in the argon and nitrogen contents in the argon fraction ； When the valve is opened wider, the opposite is true. Second, in the molecular sieve process, during pressure equalization before switching molecular sieves, as the amount of air entering the unit decreases while the oxygen production remains unchanged, the concentrations of argon and nitrogen in the argon fraction increase. In the process where liquid oxygen is injected and an oxygen flow orifice plate is located after the liquid oxygen injection evaporator, when the oxygen production is set to automatic mode while the amount of liquid oxygen injected varies, the amount of oxygen that can be extracted for primary cooling cannot be determined due to the unpredictable amount of liquid oxygen that evaporates, which makes it difficult to control the levels of argon and nitrogen in the argon fraction. 4. For the process with a liquid-loaded adsorber, during pre-cooling before switching, the concentrations of argon and nitrogen in the argon fraction decrease ； In the case of parallel operation and liquid recovery (that is, when the adsorber to be heated does not discharge liquid, the outlet valve is closed, the inlet valve is opened, and the pressure at the top of the container increases due to liquid vaporization; this allows the liquid at the bottom to enter the inlet manifold, thereby achieving liquid recovery – a method generally used when there is a shortage of cooling capacity), the contents of argon and nitrogen in the argon fraction increase accordingly. 5. For the all-distillation hydrogen-free argon production process, large fluctuations in the amount of liquid sent from the liquid argon pump to Column I for crude argon processing can also affect the argon fraction. As the liquid volume increases, the concentrations of argon and nitrogen in the argon fraction will increase ； Conversely, it decreases. 6. When a large amount of liquid is discharged, compressed air from behind the air compressor is used as the evaporation spray gas. During liquid discharge, as the amount of air entering the device decreases, the concentrations of argon and nitrogen in the argon fraction increase accordingly.