

A Survey For the Selection of Control Structure For Distillation Columns Based on Steady State Controllability Indexes.





نویسنده

Razzaghi K ,Shahraki F

منبع

Iranian Journal Of Chemical Engineering  2009  دوره : 6  شماره : 2  صفحه:29 36



چکیده

One of the important aspects of distillation control design is the choice of a good control structure since improper choice of manipulated/controlled variable pairing can lead to poor control performance. in this paper, comparison and selection of structuresis mainly based on the plant condition number. columns with reflux ratios less than unity or greater than five show large condition numbers. for the ratio structures, the results show that doubleratio structures such as the (d/(l+d))(v/b)structure have smaller values of the relative gain array element ((lambda)11) compared with singleratio structures, such as the (d/(l+d))vstructure. in addition, the relative values of (lambda)11 corresponding to the values of minimized condition number ((gamma)min), instead of condition number (lambda), provides a better basis for comparison. it has also been shown that the maximum singular value ((sigma)max) of the relative gain array (rga) is a good criteriabetween ratio and nonratio structures, and also between various ratio structures selection. at a constant reflux ratio, columns with smaller values of ((sigma)max) show small values of (gamma)min. finally, a frequencybased analysis is performed for the selection of theappropriate structure. the analyses show that although the dvstructure has a relatively small value of condition number with respect to other structures, the value of (lambda)11 is far from unity. in contrast, ratio structures have (lambda)11 values near unity. frequencybasedbehavior of ratio structures show small oscillations at higher frequencies (>1 rad/min), while the conventional lvstructures show large oscillations for smaller values of (lambda)11 at higher frequencies.

کلیدواژه

Distillation ,Control Configuration ,Condition Number ,Singular Value ,Frequency Response.

آدرس

University Of Sistan And Baluchestan, Department Of Chemical Engineering , ایران, University Of Sistan And Baluchestan, Department Of Chemical Engineering, ایران

پست الکترونیکی

fshahraki@hamoon.usb.ac.ir












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