Reducing energy consumption and CO2 emissions in extractive distillation: Part II. Dynamic behavior

The structure of thermally coupled distillation systems offers several control challenges arising from the transfer of vapor (or liquid) streams between columns. In particular, the presence of recycle streams for coupled schemes has led to the notion that control problems might be expected during the operation of these systems, in contrast to the rather well-known behavior of conventional distillation sequences. In this work, we analyze the control properties of thermally coupled extractive distillation schemes studied previously (Gutiérrez-Guerra, R., Segovia-Hernández, J.G. and Hernández, S., 2009, Reducing energy consumption and CO2 emissions in extractive distillation. Chem Eng Res Des, 87: 145-152). Control properties are analyzed with the application of the singular value decomposition technique and a closed-loop analysis. The results showed that the energy savings predicted in the complex extractive distillation sequence can be achieved along with good dynamic behavior and reductions in greenhouse gas emissions.