Method for separating and purifying mixture having small difference in boiling points

Patent metadata

Field	Value
Publication number	US-11065556-B2
Application number	US-201816633112-A
Country	US
Kind code	B2
Filing date	Aug 17, 2018
Priority date	Aug 25, 2017
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

Provided is a method of separating and purifying a mixture of components having small difference in boiling point, and the method may maximize an energy collecting amount and collect a product to be desired in high purity and high yield.

First claim

The invention claimed is:

1. A method of purifying a mixture, the method comprising:
feeding a mixture of three or more components to a first distillation column, each of the three or more components having different boiling points;
obtaining a lower fraction from a lower portion of the first distillation column, the lower fraction of the first distillation column comprising heavy components, and obtaining an upper fraction from an upper portion of the first distillation column, the upper fraction of the first distillation column comprising light components and a product to be collected;
feeding the upper fraction of the first distillation column to a second distillation column,
collecting a first lower fraction from a lower portion of the second distillation column, the first lower fraction of the second distillation column comprising the product; and
collecting an upper fraction from an upper portion of the second distillation column, the upper fraction of the second distillation column comprising lights components,
wherein heat possessed by the upper fraction of the first distillation column is fed to the lower portion of the second distillation column through a first heat exchanger, such that the heat is fed to a second lower fraction collected from the lower portion of the second distillation column,
subsequently, feeding a part of the upper fraction of the first distillation column to the second distillation column as a feed stream, and refluxing a remaining part of the upper fraction of the first distillation column to the upper portion of the first distillation column,
condensing and refluxing a part of the light components collected from the upper portion of the second distillation column to the second distillation column, and
controlling a ratio K of an upper reflux R 2 of the second distillation column and an upper reflux R 1 of the first distillation column (R 2 /R 1 ) to be from 1.05 to 1.5.

2. The method of purifying a mixture of claim 1 , wherein the difference between the boiling point of each of the three or more components of the mixture is 15° C. or less.

3. The method of purifying a mixture of claim 1 , wherein an operating pressure of the first distillation column is higher than an operating pressure of the second distillation column by 3.5 kgf/cm 2 or more.

4. The method of purifying a mixture of claim 1 , wherein the second lower fraction of the second distillation column to which the heat is fed from the first heat exchanger is returned to the second distillation column.

5. The method of purifying a mixture of claim 1 , wherein a part of the first lower fraction of the second distillation column is reheated and then returned to the second distillation column.

6. The method of purifying a mixture of claim 1 , wherein the upper fraction of the first distillation column is fed to the first heat exchanger, and a separate condenser is not provided in the upper portion of the first distillation column.

7. The method of purifying a mixture of claim 1 , wherein the heavy components collected from the lower portion of the first distillation column are reheated, and then a part of the heavy components are used in preheating of the mixture fed to the first distillation column through a second heat exchanger and then collected.

8. The method of purifying a mixture of claim 7 , wherein a remaining part of the heavy components which are collected from the lower portion of the first distillation column and then reheated is returned to the first distillation column.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Sung Kyun
• Lee Sung Kyu
• Kim Ji Hye
• Beyun Yong Mann
• Shin Joon Ho

Classifications

• B01D3/32 Primary

  Other features of fractionating columns {; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30} · CPC title

• B01D3/007 Primary

  Energy recuperation; Heat pumps · CPC title

• B01D3/00

  Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping ({evaporation in general, e.g. of liquids for gas phase reactions B01B1/005;} gas chromatography B01D15/08; destructive distillation C10B; preparation of alcoholic beverages by distillation C12H6/02) · CPC title

• B01D3/4205

  Reflux ratio control splitter · CPC title

• B01D3/4222

  Head- and side stream · CPC title