Novel Process Development of Hybrid Reactive-Extractive Distillation System for the Separation of a Cyclohexane/Isopropanol/Water Mixture with Different Feed Compositions

A cyclohexane (CY)/isopropanol (IPA)/water mixture has complex thermodynamic properties with three binary azeotropes and one ternary azeotrope. A configuration of double-column reactive-extractive distillation (DCRED) is suitable to be used for the separation of this mixture with ethylene oxide (EO) as the dehydrating agent. Taking advantage of a large liquid-liquid envelope in the ternary map of this mixture, two novel process configurations are proposed in this study to separate the mixture with the percentage of water to total feed ranging from 10 to 90 mol %. A process configuration that includes a pretreatment section followed by a DCRED section (P-DCRED) was proven to be efficient in separating the mixture with the percentage of water ranging from 50 to 90 mol %, while only the DCRED process configuration showed its superiority when dealing with the mixture with the percentage of water ranging from 10 to 40 mol %. Compared to the traditional extractive distillation (ED) and another process of ED coupled with pervaporation (PV) in the recent literature, the novel processes proposed in this study can save a total annual cost (TAC) of 20 to 80%.