In Fig. 3.a. is observed that a strong temperature drop occurs at the top of the aldehyde column, due to
that in this column section, most of the CO2 that enters to the process is recovered, as shown in Fig. 3.b.
When the ethanol content of the alcoholic water that comes out from the bottom of the aldehyde column
is under 20% w/w, and at the top the impure alcohol has 95.6% w/w of alcohol, there is minor energy
consumption in the rectifier column, because more alcohol is being recovered in the aldehyde column.