Abstract
This paper presents dynamic characteristics and control characteristics of a double-rectifying column for an air separation plant.
The dynamic characteristics of the rectifying column were examined by changing its various parameters. It was cleared that the oxygen concentration in the upper column of the double-rectifying column is influenced by the reflux flow rate changes from lower column. In order to minimize the reflux flow rate changes, a sampling control method was developed.
As a result of this experiment, a supervisory control method, which keeps the ratio of the liquid flow rate to the vapor flow rate constant in the column has been developed. It was recognized by use of dynamic simulator that the product oxygen concentration can be controlled by this method.
