Distillation device and distillation method

Patent metadata

Field	Value
Publication number	US-11103803-B2
Application number	US-201816619391-A
Country	US
Kind code	B2
Filing date	Jun 8, 2018
Priority date	Jun 8, 2017
Publication date	Aug 31, 2021
Grant date	Aug 31, 2021

Abstract

A distillation device including: a first distillation column having first top, bottom and upper outlets and first upper and lower inlets; a second distillation column equipped with a top condenser and a bottom reboiler, and having second top, bottom and upper outlets and second upper and lower inlets; a vapor recompressor; a heat exchanger; a first supply line supplying a feedstock to the first lower inlet; a first connection line transferring a first bottom flow to the second lower inlet via the heat exchanger; and a second connection line transferring a second top flow to the top condenser via the heat exchanger after passing through the vapor recompressor. The first bottom flow flowing through the first connection line and the second top flow flowing through the second connection line are heat-exchanged in the heat exchanger. A distillation method of a feedstock using the distillation device.

First claim

The invention claimed is:

1. A distillation device comprising:
a first distillation column having a first top outlet, a first bottom outlet, a first upper inlet, a first upper outlet and a first lower inlet, wherein the first upper inlet, the first upper outlet and the first lower inlet are located between the first top outlet and the first bottom outlet, and wherein the first lower inlet is located below the first upper inlet and the first upper outlet;
a second distillation column equipped with a top condenser and a bottom reboiler, and having a second top outlet, a second bottom outlet, a second upper inlet, a second upper outlet and a second lower inlet, wherein the second upper inlet, the second upper outlet and the second lower inlet are located between the second top outlet and the second bottom outlet, and wherein the second lower inlet is located below the second upper inlet and the second upper outlet;
a vapor recompressor;
a heat exchanger;
a first supply line supplying a feedstock to the lower inlet of the first distillation column;
a first connection line transferring a first bottom flow discharged from the first bottom outlet of the first distillation column to the second lower inlet of the second distillation column via the heat exchanger;
a second connection line transferring a second top flow discharged from the second top outlet of the second distillation column to the top condenser of the second distillation column via the heat exchanger after passing through the vapor recompressor,
wherein the first bottom flow flowing through the first connection line and the second top flow flowing through the second connection line after passing through the vapor recompressor are heat-exchanged in the heat exchanger prior to the first connection line transferring the first bottom flow discharged from the first bottom outlet of the first distillation column to the second lower inlet of the second distillation column via the heat exchanger.

2. The distillation device according to claim 1 , wherein the vapor recompressor is a mechanical vapor recompressor (MVR).

3. The distillation device according to claim 1 , wherein the first lower inlet of the first distillation column is located at 80% to 100% of the theoretical plate number calculated from the top of the first distillation column.

4. The distillation device according to claim 1 , wherein the second lower inlet of the second distillation column is located at 60% to 90% of the theoretical plate number calculated from the top of the second distillation column.

5. The distillation device according to claim 1 , wherein the product discharged from the first upper outlet of the first distillation column and the second upper outlet of the second distillation column is an alkene having 2 to 12 carbon atoms.

6. The distillation device according to claim 1 , wherein an absolute value (|T 2 −T 1 |) of the difference between a temperature (T 2 ) of the second top flow discharged from the second distillation column and a temperature (T 1 ) of the first bottom flow discharged from the first distillation column after passing through the heat exchanger and then flowing into the second distillation column is 40° C. or lower.

7. The distillation device according to claim 1 , wherein an absolute value (|T 3 −T 4 |) of the difference between a temperature (T 3 ) of a first bottom flow discharged from the first distillation column and a temperature (T 4 ) of the first bottom flow discharged from the first distillation column after passing through the heat exchanger and then flowing into the second distillation column is 5° C. or lower.

8. A distillation method of a feedstock using the distillation device of claim 1 , comprising steps of: introducing the feedstock into the first distillation column; and introducing the first bottom flow discharged from the first distillation column to the second distillation column,
wherein the second top flow discharged from the second distillation column is introduced into the vapor recompressor and compressed, and the first bottom flow of the first distillation column is heat-exchanged with the compressed second top flow of the second distillation column and then introduced into the second distillation column.

9. The distillation method according to claim 8 , wherein an absolute value (|T 2 −T 1 |) of the difference between a temperature (T 2 ) of the second top flow discharged from the second distillation column and a temperature (T 1 ) of the first bottom flow discharged from the first distillation column after passing through the heat exchanger and then flowing into the second distillation column is 40° C. or lower.

10. The distillation method according to claim 8 , wherein an absolute value (|T 3 −T 4 |) of the difference between a temperature (T 3 ) of the first bottom flow discharged from the first distillation column and a temperature (T 4 ) of the first bottom flow discharged from the first distillation column after passing through the heat exchanger and then flowing into the second distillation column is 5° C. or lower.

11. The distillation method according to claim 10 , wherein the first bottom flow is vaporized in the process of passing through the heat exchanger.

12. The distillation method according to claim 8 , wherein a low-boiling substance is discharged from the first upper outlet of the first distillation column and the second upper outlet of the second distillation column, and a high-boiling substance is discharged from the second bottom outlet of the second distillation column.

13. The distillation method according to claim 12 , wherein the purity of each of the low-boiling substance and the high-boiling substance is 99 wt % or more.

14. The distillation method according to claim 12 , wherein the low-boiling substance is an alkene having 1 to 12 carbon atoms.

15. The distillation method according to claim 12 , wherein the high-boiling substance is an alkane having 1 to 12 carbon atoms.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Tae Woo
• Lee Sung Kyu
• Shin Joon Ho
• Choo Yeon Uk

Classifications

• B01D1/28

  with vapour compression · CPC title

• B01D1/2856 Primary

  The compressed vapour is used for heating a reboiler or a heat exchanger outside an evaporator · CPC title

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title

• C10G53/02 Primary

  plural serial stages only · CPC title

• B01D3/007

  Energy recuperation; Heat pumps · CPC title