START-UP OF DISTILLATION COLUMN BASED ON A SIMPLE START-UP ALGORITHM

As shown in the previous paper, a characteristic function MT which is easily calculated at any instant by using the observed values of temperature in the column is useful in determining the optimum switching time from total reflux operation to steady-state operation where the initial composition in each tray is equal in value. The applicability of the characteristic function defined in the previous paper is examined experimentally for the more realistic start-up of a distillation column with the following steps. 1. Feed is supplied through the feed tray until holdup in each tray in the stripping section is filled up. 2. Total reflux operation is initiated. 3. Reflux is switched from total reflux operation to steady-state operation at appropriate switching time. © By THE SOCIETY OF CHEMICAL ENGINEERS, JAPAN.