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The stability and adjustment of the working condition of argon production system
Generally speaking, the refined argon system has little influence on the main tower and the crude argon system, which is mainly the contradiction between the crude argon system and the liquid nitrogen rectification system of the main tower.
First of all, the oxygen content of argon fraction must be well controlled to make it within the normal range, because it is the basic guarantee for the whole rectification of argon production, its control is mainly realized through the working condition adjustment of the main tower and the crude argon system.
Another major monitoring quantity is the oxygen content on the top of the first-class crude argon, because whether the crude argon system affects the rectification of the main tower or the rectification of the main tower affects the crude argon system, all of them must be shown through the transition point of oxygen content on the top of the first-level crude argon tower in the middle, which can reflect the whole set of interstate rectification working condition of air separation condition in time.
If the oxygen content on the top of the first-class crude argon tower is lower than the normal one, there are two possibilities: first, the gas extraction volume of crude argon products at the top of the first-level crude argon tower is too small or the inlet argon distillation volume of the first-level crude argon tower is too large. Rough method: air volume in the Tower: Content of argon fraction: crude argon flow = 1:0. 31: 0.00806, if the gas extraction volume of crude argon product is too small, it will cause excess content of argon in the crude argon tower, which will make the content of argon in the gas and liquid fraction higher and the content of oxygen lower during the rectification process of the crude argon tower, it will show the purity on the top of the first-class crude argon Tower, and the result of this situation is that the excess argon gradually returns to the upper tower through the reflux of the liquid in the crude argon tower, it is bound to cause a large amount of liquid argon mixed with liquid oxygen at the bottom of the upper tower, which will lead to the deterioration of the product's oxygen purity. The measures taken are to appropriately increase the extraction amount of crude argon to keep the balance of oxygen-argon distillation. If the extraction amount of argon is too large, the continuous results are similar, and measures should be taken to reduce the amount to the normal value. The second is caused by the rectification working condition of the upper tower, and there are also two factors:
1. it is because the oxygen content of argon fraction at the extraction port is relatively low, which indicates that the argon gathering area of the upper tower moves down. At this time, the most dangerous thing is that the excess nitrogen is brought in. When the nitrogen content exceeds the limit of the allowable amount in the crude argon tower, firstly, it shows the decrease of oxygen content on the top of the first-class crude argon tower after rectification; secondly, it shows the decrease of purity of crude argon at the outlet of the second-class crude argon tower, the serious consequence of this State continuing is the destruction of the rectifying working condition of the crude argon system. Therefore, in the normal production process, we should try every means to prevent the oxygen content in the argon fraction from being lower than the allowable range of the normal value, this is the basic guarantee of the stable working condition of the whole rectification of argon production, and the measures taken are to adjust the rectification working condition of the upper tower and reduce the purity of the dirt nitrogen (reduce the oxygen production and increase the quantity of the dirt nitrogen, reduce liquid nitrogen return flow, etc.) make the argon gathering area move up, and the composition of argon fraction reaches the normal value; at the same time, discharge a large amount of crude argon product gas, and eliminate the excessive nitrogen in the crude argon tower, restore the normal rectification condition of crude argon.
2. if the oxygen content of argon fraction in the upper tower is relatively high, the argon gathering area will move up, and measures will be taken to improve the purity of sewage nitrogen (increase oxygen production, reduce sewage nitrogen flow, and increase liquid nitrogen return flow) to make the argon gathering area move down. On the contrary, if the gas oxygen content on the top of the first-class crude argon tower is relatively high. This is because the extraction quantity of crude argon is too much or the extraction quantity of argon fraction is too small, which causes the imbalance of oxygen and nitrogen distillation. The measure is to reduce the flow rate of crude argon or increase the flow rate of argon distillation, of course, sometimes in order to produce less or no argon, it is necessary to increase the flow of sewage nitrogen so that the residual argon can be discharged through sewage nitrogen.
