What are the serious consequences of the top temperature of a distillation column being lower than the dew point temperature?
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The top temperature of the distillation column in my workshop is 103 degrees. Based on the partial pressures, the dew point temperature is 108 degrees. Due to the low top temperature, a large amount of water ends up in the overhead stream; 20% of the water is present in the diesel distillate. Have any of you encountered this situation?
It corresponds to the operating conditions used for cleaning a distillation column after salt accumulation there; this can lead to equipment corrosion. When there are fluctuations in the system, a large amount of water vaporizes instantly, damaging the tray plates
This post was last edited by BJYTABC on 2010-8-5 02:17. Reply 1# mcz007: Great question! The temperature at the top of the distillation tower is lower than the dew point temperature; as you calculated, it is 108°C, but in practice it is 103°C. Water exists in a gaseous state only when the temperature is above 108°C, while it is in a liquid state below that temperature. At 103°C, a large amount of liquid water is present. Therefore, it is recommended that you increase the top temperature of the fractionation tower to above 108°C. At the same time, enhance dehydration in the top circulation and diesel systems to prevent pump cavitation.