Method for producing and purifying 1,3-butadiene

Patent metadata

Field	Value
Publication number	US-10766846-B2
Application number	US-201716341500-A
Country	US
Kind code	B2
Filing date	Oct 12, 2017
Priority date	Oct 14, 2016
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

The invention relates to a method for producing butadiene that is fed with a butanediol feedstock, with said method comprising at least:
a) An esterification step comprising:
A reaction section; A separation section producing a butanediol diester effluent, a water effluent, and a carboxylic acid effluent;
b) An esterification pyrolysis step; c) A separation step comprising at least:
A cooling section producing a liquid pyrolysis effluent and a vapor pyrolysis effluent; A gas-liquid washing section that is fed at the top with a fraction of the carboxylic acid effluent that is obtained from the separation section of step a) and at the bottom with said vapor pyrolysis effluent and producing at the top a butadiene effluent and at the bottom a washing effluent; in which a carboxylic-acid-rich stream comprising at least a portion of the liquid pyrolysis effluent is recycled to step a);
d) A separation step.

First claim

The invention claimed is:

1. A method for producing butadiene from a butanediol feedstock, said method comprising:
a) An esterification step comprising:
feeding a reaction section said butanediol feedstock, a carboxylic-acid-rich stream that is obtained from step c), and at least one fraction of a carboxylic acid effluent that is obtained from a separation section of step a) said reaction section comprises an acid catalyst and is operated at a pressure of between 0.01 and 1.0 MPa, and at an MMH in the reaction section (molar flow rate of diol feeding said section with a catalyst mol number in said section) of between 0.05 and 25 h −1 to produce a reaction section effluent comprising butanediol diester;
separating in the separation section the reaction section effluent into at least one butanediol diester effluent, a water effluent, and the carboxylicacid effluent;

b) A pyrolysis step comprising feeding a pyrolysis reactor with at least said butanediol diester effluent that is obtained from the esterification step a), said pyrolysis carried out at a temperature of between 400 and 650° C. to produce a pyrolysis effluent;
c) A separating step for separation of said pyrolysis effluent that is obtained from step b), comprising at least:
cooling said pyrolysis effluent in a cooling section to a temperature that is lower than 150° C. to produce a liquid pyrolysis effluent and a vapor pyrolysis effluent;
feeding the top of a gas-liquid washing section with at least one fraction of the carboxylic acid effluent that is obtained from the separation section of step a) and at the bottom of the gas-liquid washing section with said vapor pyrolysis effluent to produce a butadiene effluent at the top and a washing effluent at the bottom;
recycling at least a portion of the liquid pyrolysis effluent to step a) as the carboxylic-acid-rich stream;

d) A purification step that is fed with the butadiene effluent that is obtained from step c) comprising at least:
introducing a stream comprising water to the top of a second gas-liquid washing section and introducing at the bottom of the second gas-liquid washing section the butadiene effluent that is obtained from step c) and producing a hydrated butadiene effluent and at the bottom an aqueous washing effluent;

eliminating water, butenes and light products comprised in the hydrated butadiene effluent in a final purification section to produce butadiene.

2. The method according to claim 1 , in which said butanediol feedstock comprises at least 90% by weight of a butanediol that is selected from the group that consists of 2,3-butanediol, 1,4-butanediol, and mixture thereof.

3. The method according to claim 1 , in which the carboxylic acid that is used is selected from the group that consists of formic acid, acetic acid, propanoic acid, butanoic acid, and benzoic acid.

4. The method according to claim 1 , in which the ratio of the molar flow rates of butanediol and carboxylic acid at the inlet of said reaction section of said step a) is between 2 and 6.

5. The method according to claim 1 , in which the carboxylic acid that is used is acetic acid.

6. The method according to claim 5 , in which said separation section of said step a) comprises heterogeneous azeotropic distillation in the presence of a driver.

7. The method according claim 1 , in which said cooling section of said step c) comprises quenching, with the quenching liquid being at least one fraction of said liquid pyrolysis effluent, cooled in advance.

8. The method according claim 1 , in which said cooling section of said step c) comprises quenching, with the quenching liquid being at least one fraction of said washing effluent that is obtained from said washing section of said step c).

9. The method according to claim 7 , in which said cooling section of said step c) is implemented in a quenching tower in which a first quenching liquid, comprising a fraction of said liquid pyrolysis effluent that is cooled in advance, is introduced at an intermediate position within the quenching tower, and a second quenching liquid, consisting of the washing effluent that is obtained from the washing section of said step c), is introduced at a position that is located above said first quenching liquid, along a vertical axis.

10. The method according to claim 1 , in which said carboxylic-acid-rich stream that is recycled to step a) comprises, in addition to at least a portion of the liquid pyrolysis effluent, at least one fraction of said washing effluent that is obtained from the washing section of said step c).

11. The method according claim 1 , in which the carboxylic-acid-rich stream comprises purified liquid pyrolysis effluent.

12. The method according to claim 7 , in which a fraction of purified liquid pyrolysis effluent is used to feed the cooling section of said step c) as a quenching liquid.

13. The method according claim 1 , in which said carboxylic-acid-rich stream comprises non-purified liquid pyrolysis effluent from step c).

14. The method according to claim 1 , in which an addition of carboxylic acid from a source that is external to the method is fed in a mixture with the carboxylic-acid-rich stream that is obtained from step c) and/or the fraction of the carboxylic acid effluent that is obtained from the separation section of step a).

15. The method according to claim 1 , in which the stream comprising water that feeds the gas-liquid washing section of said step d) comprises the water effluent that is obtained from the separation section of said step a).

Assignees

• Ifp Energies Now
• Michelin & Cie

Inventors

• Jacquin Marc
• Pacheco Nuno
• Dastillung Rejane
• Couderc Sophie
• Fauvarque Nuytien Claire

Classifications

• C07C7/005

  Processes comprising at least two steps in series · CPC title

• C07C1/213 Primary

  by splitting of esters · CPC title

• C07C67/08 Primary

  by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds · CPC title

• C07C7/06

  by azeotropic distillation · CPC title

• C07C69/16

  of dihydroxylic compounds · CPC title