| Titre : | Unusual control structure for high reflux ratio distillation columns (2010) |
| Auteurs : | William L. Luyben, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Industrial & engineering chemistry research (Vol. 48 N° 24, Décembre 2009) |
| Article en page(s) : | pp. 11048–11059 |
| Note générale : | Industrial chemistry |
| Langues : | Anglais |
| Tags : | Unusual--Control--Structure--High Reflux--Ratio--Distillation--Columns |
| Résumé : | Distillation control wisdom suggests that reflux flow rate should be used to control the reflux-drum level when the reflux ratio is large (>3). In the typical case where a single-end temperature control structure is used, reboiler heat input is used to control a tray temperature at an appropriate location in the column. When the reflux ratio is large and reflux is used to control the reflux-drum level, a frequently used scheme controls the reflux ratio by measuring the reflux flow rate and rationing the distillate flow rate to the reflux flow rate. However, in many single-end distillation control structures, the inherent ability to handle feed composition disturbances is better for a fixed reflux-to-feed ratio than for a fixed reflux ratio. Using reflux to control the reflux-drum level precludes the use of this structure. This dilemma can be resolved by using an unusual control structure in which the reflux-drum level is controlled by reboiler heat input and a tray temperature is controlled by manipulating the distillate flow rate. The effectiveness of this nonconventional structure is demonstrated in this paper for a highly nonlinear azeotropic system of water, acetic acid, and formic acid. |
| ISSN : | 0888-5885 |
| En ligne : | http://pubs.acs.org/doi/abs/10.1021/ie9010589 |
