(229h) Energy-Saving Self-Entrained Heterogeneous Azeotropic Distillation for Separating Immiscible Systems

Immiscible mixtures
usually form in petroleum, biofuel, pharmaceutical, chemical industries. The
corresponding mixtures could be C5/methanol, n-butanol/water, and 2-pentanone/4-heptanone/water, etc. Any of
them commonly presents heterogeneous azeotrope, so conventional distillation
cannot achieve the separation completely. Fortunately, the heterogeneity of the
system should be fully utilized to get the separation complete due to the
formation of heterogeneous azeotropes such that it offers considerable investment
reduction and energy saving. This work aims to summarize the separation of
immiscible systems via self-entrained heterogeneous azeotropic distillation and
use 2-pentanone/4-heptanone/water system as a case study to demonstrate the
benefit potential. The design, operation and control for this common process were
systematically investigated via
navigating residue curve maps and balancing total annual cost and product loss.

Figure 1: Ternary
phase and residue curve map analyses for 2-pentanone/4-heptaone/water system
and the corresponding process flowsheet: (S1) Sequence without 2-pentanone
recovery in R2 and fed to a stripper, (S2) Sequence with 2-pentanone
recovery in R2 and fed to a stripper, (S3) Sequence without 2-pentanone
recovery in R2 and fed to a flash, (S4) Sequence with 2-pentanone recovery in
R2 and fed to a flash