Air-cooled tower issues
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In order, the pictures are a bit messy; I’m sorry about that. I would like to ask for some advice. The exit temperature of the air-cooled tower rises from 8 degrees to 15 degrees over a period of about 10 minutes. The pressure in the upper tower is 39.8 KPA, the air intake volume is around 23,800, and the oxygen output is slightly over 4,500. When this situation occurred, the waste nitrogen vent valve was opened, and the pressure in the upper tower dropped to 39 KPA. I would like to know: 1. Why does this happen? Is the air intake too large? 2. Will water overflow from the water-cooled tower affect the air-cooled tower? 3. The flow rate of the cooling pump increased to 102 T/H and could not be reduced; a preliminary inspection of the instruments suggested that this might be due to an out-of-range reading, and a more detailed examination will have to wait until the morning. Could it be that changes in flow rate caused variations in the opening degree of the cooling pump, thereby reducing the flow rate and affecting the outlet temperature of the air-cooling tower? Because the flow rate fluctuates significantly when switching to use the cooling pump
I set both the cooling water inlet and the waste discharge from the air-cooled tower to manual control; by keeping the liquid level at 1250 mm, everything works fine, and the outlet temperature has also decreased. Why is this happening?
This post was last edited by CHANGBAISHI on 2018-10-19 at 11:07. It was caused by your improper handling, specifically due to the large fluctuations in flow rate that occurred when switching to the cooling pump. If you don’t take any action, no problems will arise; so it’s your actions that cause the issue: lol. If you ask why again, it’s because your traffic control is not functioning properly. It's your good luck that this didn’t result in water being carried in the air from the air cooling tower.
No, I’m asking why the outlet temperature of the air-cooled tower is high at the beginning At that time, it was still under DCS automatic control. I noticed a significant change in the water flow rate, so I decided to try switching pumps to see what would happen; I was also quite surprised:dizzy:
Why does the temperature of room-temperature water rise from 18 degrees to 25 degrees?
I don’t know either; maybe it dropped to 18 degrees for a moment before going back up to 25 degrees. I didn’t pay attention to that at the time
There are several reasons for the high exit temperature of the air-cooled tower: the temperature and flow rate of the warm water, the temperature and flow rate of the chilled water, and the volume of air entering the tower. Based on your description, the volume of air does not change much, while the temperature of the chilled water changes slightly but not significantly, and its flow rate remains constant. Therefore, the main issue lies in the temperature and flow rate of the warm water. There are currently two main problems: 1. The temperature of the water at room temperature changes significantly, ranging from 18.4°C to 25.6°C; it is necessary to analyze the reasons for these fluctuations in water temperature ； 2. The flow rate of the normal temperature water flow control valve FIC1101 fluctuates excessively, ranging from 45.8 to 102.7 t/h; the opening degree of the valve’s OP value changes significantly. To determine the cause of these flow rate fluctuations, it is necessary to check whether there is poor cavitation in the pump, whether the FIC1101 valve is faulty, or whether there are debris in the pipes that cause the valve to stick. It is essential to ensure that these conditions remain unchanged in order to identify the root cause. This is actually quite serious; if there are excessive fluctuations, there is a risk of water entering the molecular sieve
I think the same way; room temperature water should be fine. It’s possible that there was a sudden change in temperature at that moment, with everything being normal at other times. I asked my supervisor and colleagues, and they said that this situation occurred in other shifts as well 5 days ago. It seems that an abnormal flow rate in the cooling pump is what caused its valve opening to be abnormal. What’s unclear to me is why, when this happened, the cooling pump was set to 100% capacity while the drain valve was only opened to 30%, yet the outlet temperature still increased And why did the temperature drop again after switching to manual mode?
Changes in water volume will definitely affect the temperature. Under normal conditions, when there are small changes in water volume, the temperature change is also small. If the water volume suddenly increases, the total heat content of the water increases as well. Moreover, since the amount of hot nitrogen gas entering the cooling tower decreases, the total amount of cooling capacity available also decreases. With this increase and that decrease, the water temperature will surely be higher than before. Since the volume of gas flowing through the system remains unchanged, this will inevitably lead to an increase in temperature.
The flow rate changes significantly; switching pumps carelessly will not reduce the flow rate, so do not switch them arbitrarily