I would like to ask about the relationship between the top temperature of a fractionation tower and the dry point of the top naphtha
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As the title suggests, I would like to ask about the relationship between the top temperature of the distillation tower and the dry point of the top naphtha Other conditions: with pressure, feed temperature, etc. remaining unchanged.
A higher tower top temperature results in a higher dry point of the naphtha; conversely, a lower tower top temperature leads to a lower dry point.
The dry point of naphtha depends on the heaviest component in the naphtha/vent gas mixture. A decrease in the top temperature implies an increase in the reflux ratio, resulting in a larger amount of cold material entering the tower. The heavier components present in the tower top vapor are more likely to condense into a liquid phase and flow downward. Since these heavier components are already condensed into a liquid phase at the tower top, they cannot appear in the naphtha/top oil, and as a result, the dry point of the naphtha is lower. Conversely, by the same logic, with less reflux, the heavier components in the gas phase cannot all be condensed and are carried out of the tower along with the lighter components, resulting in a higher dry point for the naphtha.