On the relationship between column yield and column temperature

The heavy things have come out from the top, so it’s even heavier down there

Hahahahaha, it’s pure wordplay. Heavier,,, even heavier: lol It’s clear which one is heavier and which one is lighter

You mean that since the weight is already up there, it must be even heavier down below, right?:lol

It’s really a word game; everything described is correct, but these two sentences are of no use

The statement that the components at the bottom of the tower become “heavier” means that the initial boiling point within the distillation range—from the initial boiling point to the dry point—has increased. An elevated initial boiling point essentially indicates that the oil has become heavier. This increase in weight implies a rise in temperature, which is necessary to vaporize the lighter components of the oil at the bottom of the tower. A decrease in the amount of oil collected at the top of the tower signifies a lower temperature there; consequently, the dry point of the top-stream oil also drops as the temperature decreases, making the oil lighter. Due to the reduced output from the top of the tower, the volume of vapors generated there diminishes. With the workload on the overhead condenser remaining unchanged, this leads to a drop in the temperature of the top-stream oil. As a result, the condenser temperature falls, the volume of oil extracted from the top decreases, and more oil accumulates at the bottom. The temperature of the bottom-stream oil corresponds to its initial boiling point under the current pressure. Since the heavier components from the top-stream oil have descended into the bottom stream, the initial boiling point of the bottom oil decreases. Hence, the temperature at the bottom of the tower also drops compared to when the volume of top-stream oil extraction was higher

To vaporize the heavier components to the top of the tower, a higher temperature is required; therefore, the more heavy components are distilled out at the top, the heavier the remaining heavy components at the bottom of the tower, and simultaneously, the temperature at the bottom of the tower becomes higher. The opposite is also true: the fewer high-boiling components at the top of the tower, the lower the thermal load there, and thus the lower the temperature.

The fundamental issue is the variation in the reflux ratio; generally, the higher the reflux ratio, the more light components are present at the top of the tower, and the fewer heavy components. The larger the reflux ratio, the more liquid condensed in the condenser returns to the top of the tower, causing the temperature at the top to drop and allowing heat to be transferred to the bottom of the tower.

I’ll share my opinion; if there are any mistakes, please feel free to point them out, experts! {:9001:} It can be simply viewed as a separation of the two substances; when there are more heavy components at the top of the tower, it means that there are fewer light components at the bottom, and the concentration of heavy components increases – which is why it is said that the mixture has become heavier. The issue of decreasing tower top temperature is that, under the same heat exchange conditions, a reduction in flow rate leads to a lower temperature. The increase in light components at the bottom of the tower is due to the fact that, when the amount taken out from the top of the tower is small and the reflux volume increases, the light components move downward to the bottom of the tower.

Could you tell me what book it is? Thank you