Side Draw with a Practical Automatic Purging Strategy

5 SIDE DRAW WITH A PRACTICAL AUTOMATIC PURGING STRATEGY 

ACETIC ACID-WATER (ISOBUTYL ACETATE AS THE ENTRAINER) 

An optimum overall control strategy is also proposed for this column system to hold both bottom and top product specifications in spite of +10% feed rate and +10% feed water composition load disturbances. Several alternative control structures are compared using dynamic simulation. The proposed overall control strategy is very simple, requiring only one tray temperature control loop in the column. This simple overall control strategy can easily be implemented in industry. 

In the latter part of this chapter, design and operation of an industrial column for acetic acid dehydration with feed impurity are investigated. This feed impurity component during normal operation will not leave the column system through either top decanter AO stream or column bottoms stream. The accumulation of this component inside the column system is illustrated via rigorous dynamic simulation. A side stream is proposed to solve the accumulation problem of this component. Appropriate side-stream location and flowrate are determined by TAC analysis. 

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