Abstract
The heat consumption of distillation column is considered for both the open steam and reboiler systems. The Ponchon-Savarit method is used for calculations.
Cases (A), (B) in Fig. 1 show the calculated results of the bottoms product composition and the theoretical number of plates when feed composition, distillate composition, reflux ratio, heat consumption, and the total number of plates are the same. Cases (A), (C) in Fig. 1 show the calculated results of heat consumption when feed composition, distillate composition, reflux ratio, bottoms product composition, and the total number of plates are the same. The enthalpy-composition diagram used is shown in Fig. 2. The calculated results are summarized in Table 1.
Comparing the results of cases (A), (B) in Fig. 1. it is found that the open steam method requires much more theoretical number of plates, but the ethanol content in the bottoms product becomes smaller. Comparing the results of cases (A), (C) in Fig. 1, it is found also that less heat is required by heating with open steam than with a reboiler. This heat saving effect becomes greater as the ethanol content in the bottoms product becomes larger.
