Design and Control of an Isopropyl Alcohol Dehydration Process via Extractive Distillation Using Dimethyl Sulfoxide as an Entrainer

Abstract

In this paper, design and control of an isopropyl alcohol (IPA) dehydration process via extractive distillation have been investigated. The heavy-boiling entrainer used to aid the separation is dimethyl sulfoxide (DMSO). The design flowsheet includes an extractive distillation column and an entrainer recovery column with the top product of the extractive distillation column to be IPA and the top product of the entrainer recovery column to be water. The bottom product of the entrainer recovery column is the recovered DMSO which is recycled back to the extractive distillation column. The optimal design flowsheet of this complete process has been established showing that the total annual cost and the needed steam cost of this design flowsheet is significantly less than a competing design flowsheet via heterogeneous azeotropic distillation. A very simple overall control strategy has also been proposed which requires only one tray temperature control loop in each column to hold the high-purity specifications of the two products. Dynamic simulations reveal that fixing of the reflux ratio is not a suitable control strategy. Instead, the strategy to fix the two reflux flow rates should be used to reject feed disturbances.

Extractive Distillation Process Optimisation of the 1.0-1a Class System, Acetone - methanol with Water

“…The condenser heat duty is then neglected despite its impact on the process cost; and the regeneration column is not taken into account. Arifin and Chien (2008) used the total annual cost (TAC) including capital cost and operating cost as objective function. They showed that it exhibits a minimal value vs the total number of trays for the extractive process sequence columns.…”

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

“…The constant reflux ratio and constant entrainer feed rate operating policy, and another policy to allow these two operating variables to be varied, will be compared in order to further improve batch operation. Arifin and Chien (2008) have investigated the control of an isopropyl alcohol (IPA) dehydration process via extractive distillation. The heavy-boiling entrainer used to aid the separation is dimethyl sulfoxide.…”

Optimal design of extractive distillation for acetic acid dehydration with N-methyl acetamide

“…In the stripping section, the αwater-AA is much lower than that in the extractive section (between 2 and 3). This phenomenon is different from other extractive distillation systems such as ethanol-water [33], acetone-methanol [25], isopropyl alcoholwater [32] and so on. The reason is that even there is not azeotrope formation between water and AA, the average relative volatility of water is close to unity (see Fig.…”