Method for preparing ethylene with improved energy efficiency

Patent metadata

Field	Value
Publication number	US-10294177-B2
Application number	US-201715762426-A
Country	US
Kind code	B2
Filing date	Apr 7, 2017
Priority date	May 10, 2016
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

Provided is a method for preparing ethylene with improved energy efficiency which can reduce energy due to direct heat exchange between processes.

First claim

The invention claimed is:

1. A method for preparing ethylene with improved energy efficiency, comprising:
providing a C 2 compound isolated from a de-ethanizer column to an acetylene converter;
converting acetylene of the C 2 compound into ethylene and ethane;
transferring the C 2 compound containing ethylene and ethane converted from acetylene to a first C 2 splitter to isolate and discharge a part of the ethylene; and
transferring a lower stream containing ethane and a remaining part of the ethylene of the C 2 compound, which are not discharged from the first C 2 splitter, to a second C 2 splitter, to isolate and discharge the remaining part of the ethylene of the C 2 compound, and converting the ethane of the C 2 compound into ethylene to be recycled,
wherein a heat exchanger is installed between the de-ethanizer column and the first C 2 splitter to perform direct heat exchange between the de-ethanizer column and the first C 2 splitter, a difference in pressure between the de-ethanizer column and the first C 2 splitter to enable the heat exchange is 4.5 kgf/cm 2 G or more, and a concentration of ethylene contained in the lower stream of the first C 2 splitter is 70 to 80 mol %, and
wherein the heat exchange is performed between the lower stream of the first C 2 splitter and an upper stream of the de-ethanizer column.

2. The method of claim 1 , wherein a heat exchange amount obtained by the heat exchanger varies according to a difference (P1−P2) between a pressure of the de-ethanizer column (P1) and a pressure (P2) of the first C 2 splitter and a concentration (mol %) of the ethylene contained in the lower stream of the first C 2 splitter.

3. The method of claim 1 , wherein the difference between the pressure of the de-ethanizer column and the pressure of the first C 2 splitter is 4.5 to 15 kgf/cm2 G.

4. The method of claim 1 , wherein the lower stream of the first C 2 splitter is transferred to the second C 2 splitter or provided to the heat exchanger.

5. The method of claim 1 , wherein the lower stream of the first C 2 splitter allows a part of the upper vapor of the de-ethanizer column to be condensed after being provided to the heat exchanger.

6. The method of claim 1 , wherein, when the heat exchange is performed between the de-ethanizer column and the first C 2 splitter, an amount of a refrigerant used in the upper part of the de-ethanizer column is decreased.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Sung-Kyun
• Lee Sung-Kyu
• Kim Tae-Woo
• Shin Joon-Ho
• Choo Yeon-Uk
• Park Sa-Eun

Classifications

• C07C11/04

  Ethene · CPC title

• C07C7/04 Primary

  by distillation · CPC title

• C07C11/24

  Acetylene (production of acetylene gas by wet methods C10H) · CPC title

• C07C5/09

  to carbon-to-carbon double bonds · CPC title

• C07C9/06

  Ethane · CPC title