Using temperature profile for product quality estimation on a distillation column

Abstract

A composition estimator based on eight temperature measurements has been implemented on a deethanizer column at the Ethylene plant at Statoil in Stenungsund, Sweden. The column separates a mixture of four components. The estimator is a simple static regression estimator and the regression method is the Partial Least Square Regression, which is extensively employed in chemometrics. The estimator was first tested off-line with very good results, and then also on-line in closed loop for composition control, where it now is implemented. Very accurate estimates have been obtained using this estimator. The need for updating seems limited, and the method should be applicable on a wide range of distillation columns provided the temperature sensors are well distributed and the number is not too small.