How is the moisture content of the air entering the lower tower determined?
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Dear sea friends, please offer your guidance and discussions: How is the moisture content of the air entering the tower determined? What are the effects of excessive moisture content on operating conditions?
This question. . . . . . Simply put: there are online monitors to measure the moisture content in the air. Water removal from the air is done to prevent blockages in the pipelines once the air enters the heat exchangers, which could lead to an increase in the pressure difference between the inlet and outlet of the main heat exchanger, or even complete blockages. Then production has to be stopped for system heating and purging.
The moisture content of the air entering the lower tower can be determined from the opening degree of the night sky throttle valve and the level of the main cooling liquid. Excessive moisture content can lead to a decrease in the purity of the liquid air and oxygen.
Reply to 3# Taoge2: The key is the purity of the liquid air. If the purity of liquid oxygen is poor, it can’t be determined that it’s just an issue with high humidity in the air!
It is advisable for the humidity level of the air entering the lower tower to be around 3%. If the humidity is too high, the pressure in the lower tower decreases, the amount of steam rising decreases as well, and the purity of nitrogen in the lower tower drops, which leads to an increase in the temperature difference in the main cooler. You should determine the humidity level of the air based on the pressure in the lower tower and the temperature of the air entering it
A high moisture content in the air entering the lower tower means that there is less gas phase in the compressed air; as a result, fewer gas phases are available for distillation in the lower tower, which leads to a decrease in the amount of nitrogen from that tower that goes into the main condensation evaporator. The evaporation rate on the oxygen side of the main condensation evaporator decreases, resulting in a lower purity of liquid oxygen. The basis for this judgment is that an increase in cooling capacity leads to a decrease in the purity of liquid oxygen, which suggests that the moisture content in the air entering the lower tower has increased. Hope to discuss further, thank you
In my opinion, controlling the moisture content mainly involves monitoring the temperature of the low-pressure air entering the tower. Based on the design parameters, if the temperature is low, it indicates a high moisture content; if the temperature is high, then the moisture content is low. It is necessary to monitor the temperature continuously and make adjustments as needed. Waiting until problems arise in the distillation process inside the tower before taking action is too late – by that point, the system is already experiencing fluctuations
Reply to 7# zhh8938: This isn’t suitable either, because the pressure at the bottom of the tower changes! Different pressures correspond to different temperatures! If both pressure and temperature are used, it is necessary to consult a chart, but such charts are hard to obtain; and even if they are available, it is difficult to get accurate readings from them, as the scales on these charts cannot be detailed enough! Do any other sea friends have any other shortcuts?
The moisture content should mean that the liquefaction rate of the liquefied air before it enters the lower tower should not exceed 5%; if the moisture content is too high, it indicates that the cold zone of the heat exchanger has moved downward. In severe cases, it will affect the air intake volume and the pressure in the lower tower.