Research Progress of Hybrid Distillation/Crystallization Technology

Abstract

The hybrid distillation/crystallization process is successfully applied to separate azeotropes and closely boiling mixtures. This process can not only provide pure products, but also allow for significant energy savings. The research progress and industrial applications of hybrid distillation/crystallization are reviewed. Different sequences of hybrid distillation/crystallization process are presented based on the optimized design. The specific developments of each single unit, namely, distillation and crystallization, in the hybrid process are outlined. Applications of hybrid distillation/crystallization in practical cases are highlighted and analyzed. Finally, the key issues and perspectives for further research of this integrated process are illustrated.

Purification of p-Cresol, o-Cresol, m-Cresol, and 2,6-Xylenol from the Quaternary Mixture by Three-Phase Crystallization

“…Three-phase crystallization (TPC), also known as stripping crystallization, was initially introduced by Shiau and his co-workers to separate mixed xylenes with close boiling temperatures. − Later, they applied TPC to separate chiral mixtures with the same boiling temperatures. − Basically, TPC combines melt crystallization and vaporization. Melt crystallization has long been adopted to obtain the desired crystalline solid from a liquid mixture via the solid–liquid transformation due to cooling at normal pressure. − TPC resembles melt crystallization operated at reduced pressure during the cooling process, leading to the formation of a crystalline product along with a vapor mixture from the liquid mixture via a series of three-phase transformations. If nearly all the liquid mixture is removed at the end of TPC, the final product only consists of the desired crystalline solid while the produced vapor can be collected and recycled.…”

Chiral Purification of S‐Methyl‐2‐chloropropionate from Enantiomer Mixtures by Three‐Phase Crystallization

“…Basically, TPC is a new separation technology, which combines melt crystallization and vaporization. For melt crystallization, the desired crystalline solid is formed from a liquid mixture via the solid-liquid transformation occurred at normal pressure during the cooling process [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. TPC resembles melt crystallization operated at reduced pressure during the cooling process, leading to the formation of desired crystalline solid along with vapor mixture from a liquid mixture via a series of three-phase transformations [1][2][3][4][5][6][7][8].…”

The Influence of the Solid Solution Formation on Purification of L-Menthol from the Enantiomer Mixture by Three-Phase Crystallization

“…Melt crystallization is an important separation process for the purification of organic compounds [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] and enantiomeric mixtures [28,29]. The unique feature of melt crystallization is that no solvent is required; however, the subsequent separation of formed crystals from melt is often a challenging task for downstream processing.…”