Purification device and purification method using the same

Patent metadata

Field	Value
Publication number	US-9770674-B2
Application number	US-201414783715-A
Country	US
Kind code	B2
Filing date	Aug 1, 2014
Priority date	Aug 1, 2013
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

Provided are a purification device and method. The purification device and method make most use of an internal heat source in the distillation column in the process of distilling the raw material, and reduce use of an external heat source. Thereby, the purification device and method can improve energy efficiency of all the processes.

First claim

The invention claimed is:

1. A purification method for recovering n-hexane using a purification device,
wherein the purification device comprises a first distillation section comprising a first distillation column that has a first raw material feed port into which a raw material is introduced and that distills the introduced raw material, a first condenser that condenses a top stream discharged from a top section of the first distillation column and flows a part of the top stream back to the first distillation column, and a first discharge route that delivers a material discharged from a lower section of the first distillation column;
a second distillation section comprising a second distillation column that has a second raw material feed port into which a raw material is introduced and that distills the introduced raw material, a second condenser that condenses a top stream discharged from a top section of the second distillation column and flows a part of the top stream back to the second distillation column, a second reboiler that heats a bottom stream discharged from a bottom section of the second distillation column and flows at least a part of the bottom stream back to the second distillation column, and a second discharge route that delivers a material discharged from a lower section of the second distillation column;
a heat exchanger that exchanges heat between the top stream discharged from the top section of the second distillation column and a first bottom stream discharged from a bottom section of the first distillation column before the top stream discharged from the top section of the second distillation column is introduced into the second condenser, and
a first reboiler that heats a second bottom stream of the first distillation column other than the first bottom stream which flows through the heat exchanger, wherein the first reboiler flows at least a part of the second bottom stream back to the first distillation column, and
wherein the purification method comprises:
a process of introducing a first raw material comprising the n-hexane into the first distillation column through the first raw material feed port;
a process of introducing a second raw material comprising the n-hexane into the second distillation column through the second raw material feed port;
a process of separating each of the introduced first and second raw materials into the top and bottom streams in each of the first and second distillation columns; and
a process of exchanging heat between the top stream discharged from the top section of the second distillation column and the first bottom stream discharged from the bottom section of the first distillation column in the heat exchanger,
wherein a temperature difference generated between the top stream of the second distillation column and the first bottom stream of the first distillation column ranges from 5° C. to 25° C., and wherein a ratio (T1/T2) of a temperature (T1) of the bottom stream of the first distillation column to a temperature (T2) of the top stream of the second distillation column ranges from 0.5 to 0.96.

2. The purification method according to claim 1 , wherein a ratio (P1/P2) of an operating pressure (P1) of the first distillation column to an operating pressure (P2) of the second distillation column ranges from 0.02 to 0.85.

3. The purification method according to claim 1 , wherein the purification device further comprises a recovery unit that recovers a material discharged from the first discharge route or the second discharge route.

4. The purification method according to claim 1 , wherein a ratio (V2/V1) of a flow rate (V2) of a material discharged from the first discharge route to a flow rate (V1) of a material introduced from the first raw material feed port ranges from 0.0009 to 0.005.

5. The purification method according to claim 1 , wherein a ratio (V4/V3) of a flow rate (V4) of a material discharged from the second discharge route to a flow rate (V3) of a material introduced from the second raw material feed port ranges from 0.0009 to 0.004.

6. The purification method according to claim 3 , wherein a ratio (V6/V5) of a flow rate (V6) of the material recovered by the recovery unit to a total flow rate (V5) of materials introduced from the first and second raw material feed ports ranges from 0.001 to 0.005.

7. The purification method according to claim 3 , wherein the purification device further comprises a connection route that delivers a vapor phase of the recovery unit to the lower section of the first distillation column.

8. The purification method according to claim 7 , wherein a ratio (V7/V6) of a flow rate (V7) of the material introduced into the lower section of the first distillation column through the connection route to a flow rate (V6) of the material recovered by the recovery unit ranges from 0.5 to 0.95.

Assignees

• Lg Chemical Ltd
• Lg Chemical Ltd

Inventors

• Lee Sung Kyu
• Shin Joon Ho

Classifications

• C07C7/005

  Processes comprising at least two steps in series · CPC title

• B01D3/007 Primary

  Energy recuperation; Heat pumps · CPC title

• C07C7/04

  by distillation · CPC title

• B01D3/4205

  Reflux ratio control splitter · CPC title

• Y02P20/57

  Cross-Sectional Technologies · mapped topic