Effect of feed temperature variations on AspenPlus distillation column simulation results
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In AspenPlus, why does a change in feed temperature only result in changes in the heat loads at the bottom and top of the distillation column, with no effect whatsoever on the compositions at those same positions? However, in practical situations, with all other conditions remaining unchanged, an increase in feed temperature leads to an increase in the heavy components at the top of the tower. Why isn’t this reflected in AspenPlus?
It is related to many factors. 1. Were any design specifications taken into account during your simulation? If not, changing the feed temperature usually has an impact on the compositions at the top and bottom of the tower ； If design specifications are added, as long as the specified purity is achieved, changing the feed temperature has no effect on the composition at the top and bottom of the tower ； Furthermore, the number of plates you have set is much higher than what is required for complete separation, which results in the feed temperature having little impact on the purity of the product obtained from the tower. 2. For actual distillation columns, it is also necessary to consider what the control structure is like. Generally, changing the feed temperature has an effect on the compositions at the top and bottom of the column; however, with a proper control structure in place, small fluctuations in the feed can result in only minimal changes in the purity at the column top.
The moderator replies personally! ! Oh my god, I’m extremely grateful that the moderator took the time out of their busy schedule to reply to my post! ! It’s very insightful; no design specifications were added, and it seems that the number of trays specified is much higher than what is required for separation. I’ll try reducing the number of trays
The distillation efficiency depends on the number of theoretical plates, reflux ratio, and feed position