Method of preparing conjugated diene and device therefor

Patent metadata

Field	Value
Publication number	US-9969661-B2
Application number	US-201515021611-A
Country	US
Kind code	B2
Filing date	Oct 20, 2015
Priority date	Mar 24, 2015
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

Disclosed are a method of preparing conjugated diene and a device therefor. More particularly, disclosed a method of preparing conjugated diene, wherein generated gas including butadiene is cooled and then water discharged at a lower part is not directly treated as waste water and subjected to byproduct removal and steam-extraction to utilize converted steam, and an installation issue of an existing biological waste water disposal equipment due to an excessive amount of byproducts can be resolved, and a device therefor are disclosed.

First claim

The invention claimed is:

1. A method of preparing conjugated diene, wherein the method comprises:
oxidatively-dehydrogenating a raw material gas comprising n-butene in an oxidative dehydrogenation reactor in the presence of a catalyst to form a generated gas comprising butadiene;
contacting the generated gas with a cooling water to cool the generated gas to form a cooled generated gas and a discharged cooling water containing one or more byproducts;
subjecting the discharged cooling water to a light byproduct removal process to remove a light byproduct comprising a carbonyl compound having a boiling point of 100° C. or less and a carbon number of 4, thereby producing a remaining discharged cooling water;
subjecting the remaining discharged cooling water to a heavy byproduct precipitation process to precipitate a heavy byproduct comprising a carbonyl compound having a boiling point of 100° C. or less and a carbon number of 5 or 6, thereby producing a heavy byproduct precipitated cooling water, wherein the heavy byproduct precipitation process comprises adjusting a pH of the remaining discharged cooling water to 11 or more to precipitate the heavy byproduct;
subjecting the heavy byproduct precipitated cooling water to a filtering process to remove the precipitated heavy byproduct, thereby producing a byproduct-removed cooling water;
contacting the cooled generated gas with an absorption solvent to produce an organic solution;
stripping the organic solution to obtain crude butadiene;
converting the byproduct-removed cooling water into steam to form a converted steam; and
recycling a portion of the converted steam to the oxidative dehydrogenation reactor, wherein an amount of the converted steam recycled to the oxidative dehydrogenation reactor is 50% by weight or more based on the weight of the discharged cooling water, and an amount of a carbonyl compound contained in the converted steam is 1000 ppm or less.

2. The method according to claim 1 , wherein the light byproduct removal process is performed through distillation at a temperature range of from 80° C. to 95° C.

3. The method according to claim 1 , wherein the heavy byproduct precipitation process is performed using a neutralization tank.

4. The method according to claim 1 , wherein the contacting the generated gas with the cooling water is performed in a cooling equipment having an upper part and a lower part, the cooling water is introduced into the upper part, countercurrently contacting the generated gas that is introduced into the lower part to form a used cooling water.

5. The method according to claim 4 , wherein a portion of the used cooling water is recirculated to the upper part of the cooling equipment.

6. The method according to claim 1 , wherein a portion of the converted steam is not recycled to the oxidative dehydrogenation reactor and the precipitated heavy byproduct is incinerated.

Assignees

• Lg Chemical Ltd

Inventors

• Han Sang Jin
• Kang Jun Han
• Ko Dong Hyun
• Nam Hyun Seok
• Lee Joo Hyuck
• Han Jun Kyu
• Suh Myung Ji
• Cha Kyong Yong
• Choi Dae Heung
• Hwang Ye Seul

Classifications

• C07C5/42

  by dehydrogenation with a hydrogen acceptor · CPC title

• C07C7/005

  Processes comprising at least two steps in series · CPC title

• C07C11/167

  1, 3-Butadiene · CPC title

• C07C5/48 Primary

  with oxygen as an acceptor · CPC title

• C07C5/3332 Primary

  with metal oxides or metal sulfides · CPC title