RGA ANALYSIS FOR DISTILLATION CONTROL

This paper presents the relative gain analysis of two industrial distillation columns. Both columns involve multicomponent separation and the purpose of the relative gain analysis has been to find proper pairing of manipulated and controlled variables. The matrix oriented method of Wang and Henke has been employed in the study, The study has investigated the effects of single-precision versus double-precision programming, step-size, and tightness of convergence, upon the relative gain array. The results with single-precision programming and double-precision programming have yielded significantly different results. The results confirm that a considerable reduction in the step-size of the manipulated variables may be necessary in some cases to achieve meaningful results. They also indicate that tight convergence may be required for some columns at a considerable expense in terms of CPU time while for others, loose convergence and moderate step-sizes may be adequate, The results of this study will be useful to those who are interested in the design of distillation control systems.