The bottom temperature of the solvent regeneration tower won’t rise – what’s going on?
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The bottom temperature of the solvent regeneration tower in my company fails to rise; the steam pressure is 0.35 MPA, and once the temperature reaches 120 degrees, it becomes very difficult for it to go any higher. The steam flow rate through the reboiler is quite low; please advise, experts
Isn’t it 2.2 MPa steam?
Check the condensate system to see if there is high pressure in the condensate tank, which prevents steam from entering. Also, does your condensate tank have a pressure balance line, and is that line set to an excessive opening? Too little has been said; it’s better to have DSC
Regardless of the amount, the reboiler accepts only steam at 150 degrees and 0.35 MPa, as high temperatures can cause the solvent to undergo thermal degradation.
The main reason why the temperature at the bottom of the tower cannot rise is the low tower pressure; in the case of a regeneration tower, the temperature of the tower is controlled by pressure. The following points should be noted here: 1. The recovery rate of the regenerated acidic gas must not be lower than the calculated value; while ensuring the recovery rate at the top of the tower, steam should be used to maintain the temperature at the bottom of the tower. 2. A low temperature in the regeneration tower in the range of 120–122 is sufficient; there is no need for a very high temperature ； 3. The reason steam cannot be supplied is the absence of a cold stream; in this case, it is necessary to check the liquid inflow rate to the reboiler.
Bro, I can’t agree with your view; 120 to 122 degrees isn’t suitable for all refineries, as the feed volume varies. For some applications, 118 is sufficient; for those with high flow rates, 125 can be used. The temperature depends mainly on the amount of feed. If tower pressure is used to control the bottom temperature, high pressure prevents adequate extraction of acidic gases, which affects the quality of the lean liquid. Low pressure results in better product quality, but care must be taken to avoid overpressure in the tower. Also, if the flow rate of liquid into the reboiler is low, the temperature at the bottom of the tower will rise, as the steam cannot be cooled sufficiently; as a result, the temperature of the gas phase in the reboiler increases. I encountered this situation just a few days ago.
There are many reasons; one must determine the cause of the problem based on the actual conditions on site. Is the steam flow rate through the reboiler low because the reboiler is blocked?
The low temperature in the amine liquid regeneration tower is related to the operating load; the higher the load, the greater the pressure drop in the tower and the higher the bottom temperature. It is also related to the acid gas load – if the acid gas load is too low, the tower pressure will be low and so will the bottom temperature.
1.0.35 MPa = 3.05 KG/CM2; G = 132 degrees. Using these values, it seems reasonable for the bottom of the tower to be heated to 12X degrees. 2. I’m not familiar with the process of solvent regeneration; however, the pressure at the top of the tower should remain within a certain range, and there should be a proper ratio between the material fed into the tower and the cold reflux at the top (when evaluating using a distillation tower)