CRITERIA OF EFFICIENCY ESTIMATION OF RECTIFICATION COLUMNS

This article deals with the efficiency of rectification columns which is often measured by the value of tray efficiency or single height of packing. The analysis of the factors influencing the efficiency of the rectification process was provided. This article shows that the commonly used Murphree efficiency factor in most cases estimates the efficiency trays and packing of the rectification process with a large error.

PARAMETRIC INVESTIGATION OF FIXED-TRAY, SEMI-CONTINUOUS DISTILLATION COLUMN FOR ETHANOL SEPARATION FROM WATER

This work was aimed to evaluate the parameters affecting the separation of model fermentation broth (7 mole% ethanol) using 10-tray, semi-continuous distillation column. Ethanol compositions in distillate and bottoms were determined at different reflux ratios and feed locations. Results show that the distillation of lower ethanol concentration is better carried out at higher reflux ratio with feed charged at the middle or bottom tray for good overall tray efficiency. The distillation unit is able to purify the feed to 78 mole% ethanol in distillate. Through trial-and-error stepping off, about 81 mole% was predicted as optimum ethanol purity at reflux ratio of 2.33, while a lower reflux ratio of 1.44 was estimated for 78 mole%. Fixed-tray, semi-continuous distillation is a suitable option to concentrate fermentation broth with sufficient ethanol purity.

Theory and Application of the Lang-Gilles Observer for Distillation Processes

This thesis deals with the nonlinear full state observer for distillation processes first introduced by Lang and Gilles in 1990. The observer is very attractive in practice as it requires only few temperature measurements in each section of a distillation column and only few observer parameters need to be tuned. We provide conditions under which this observer converges and derive a simple rule for the tuning of the observer parameters. We also give a method for the on-line estimation of the Murphree tray efficiency. Such on-line methods are rarely found in ­literature. In a sequence of simulation studies, we investigate the capabilities of the observer for the estimation of the tray efficiency and for model-predictive control. The simulation studies are based on distillation processes for separation of multicomponent mixtures and one of the studies introduces a plant-model mismatch. ...