Why can the bottom liquid from the pressurized column in the three-column distillation process for methanol reach the temperature of the atmospheric-pressure column?
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During the three-column distillation of methanol, when the temperature of the sensitive plate in the atmospheric pressure column rises, it is possible to use the liquid at the bottom of the pressurized column (the feed to the atmospheric pressure column) to exert pressure. My question is: given that the temperature at the bottom of the pressurized column is so high, how is it possible for it to affect the temperature at the sensitive plate? What will be the effect if the water content in the solution at the bottom of the pressure tower becomes particularly high, when it is then used to control the temperature of the sensitive plate in the atmospheric pressure tower?
An increase in backflow will affect product quality, as well as increase steam consumption
This is a matter of adjusting the recovery ratios of the pressurized tower and the atmospheric pressure tower. There is a relationship: the higher the recovery ratio of the atmospheric pressure tower, the further upward the sensitivity plate moves; otherwise, the residual liquid level exceeds the allowed limit. In order to lower the position of the sensitivity plate, it is necessary to increase the recovery ratio of the pressurized tower, provided that the residual liquid level remains within acceptable limits. The recovery ratio of the pressurized tower is proportional to the pressure in that tower – in other words, the higher the pressure in the pressurized tower, the more methanol can be recovered. As the methanol content in the feed to the atmospheric pressure tower decreases, its load decreases as well, allowing the temperature of the sensitivity plate to be reduced relatively.