Method for dehydrating a mixture containing ethanol and n-propanol

Patent metadata

Field	Value
Publication number	US-9902662-B2
Application number	US-201415038830-A
Country	US
Kind code	B2
Filing date	Oct 8, 2014
Priority date	Nov 27, 2013
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

The present invention relates to a process for the production of a mixture of ethylene and propylene from a mixture containing ethanol and n-propanol and having a water content comprised between 30 and 75% by weight with respect to the total weight of the mixture.

First claim

The invention claimed is:

1. Process for the production of a mixture of ethylene and propylene from a mixture containing ethanol and n-propanol and having a water content comprised between 30 and 75% by weight with respect to the total weight of the mixture, in which:
a) the mixture is brought into contact, in a dehydration unit, with a dehydration catalyst chosen from:
an alumina (A) having a BET specific surface area measured according to the standard ASTM D 3663-03 comprised between 200 and 280 m 2 /g, a mean mesopore diameter comprised between 5 and 15 nm, a sodium content of less than 50 ppm by weight and a sulphur content of less than 40 ppm by weight; and
an alumina (B) having a BET specific surface area measured according to the standard ASTM D 3663-03 comprised between 130 and 180 m 2 /g, a mean mesopore diameter comprised between 14 and 20 nm, a sodium content comprised between 300 and 600 ppm by weight and a sulphur content comprised between 800 and 1300 ppm by weight;

the bringing into contact being carried out at a temperature comprised between 350 and 500° C., at a total pressure comprised between 0.2 and 2 MPa and with a weight hourly space velocity (whsv) defined as being the ratio of the mass flow rate of ethanol and n-propanol to the mass of catalyst comprised between 1 and 10 h −1 ,
b) an effluent containing ethylene and propylene is drawn off from said dehydration unit.

2. Process according to claim 1 , in which the mixture contains between 1 and 75% by weight of ethanol and between 99 and 25% by weight of n-propanol with respect to the total weight of ethanol and n-propanol.

3. Process according to claim 1 , in which the aluminas (A) and (B) are gamma aluminas.

4. Process according to claim 1 , in which the alumina (A) has a mean mesopore diameter comprised between 6 and 12 nm and preferably comprised between 7 and 11 nm.

5. Process according to claim 1 , in which the alumina (B) has a BET specific surface area measured according to the standard ASTM D 3663-03 comprised between 150 and 180 m 2 /g.

6. Process according to claim 1 , in which the alumina (B) has a mean mesopore diameter comprised between 15 and 20 nm.

7. Process according to claim 1 , in which before stage a) the mixture is brought into contact with an aromatic cut comprising a mixture of aromatic compounds having 7 to 10 carbon atoms, in a separation unit comprising a liquid-liquid extraction column, so as to separate from said extraction column an aqueous fraction and an organic fraction containing the aromatic cut, ethanol, n-propanol and said organic fraction is sent into a distillation column configured in order to provide an effluent containing the aromatic cut and a mixture containing ethanol and n-propanol and said mixture is sent into the dehydration unit.

8. Process according to claim 7 , in which the aromatic cut is a mixture of 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene.

9. Process according to claim 7 , in which the mixture containing ethanol, n-propanol and water is brought into contact with the aromatic cut is carried out in counter-current.

10. Process according to claim 1 , in which before stage a) the mixture containing ethanol, n-propanol and water is sent into a separation unit comprising a distillation column so as to separate from the distillation column an aqueous fraction and an effluent containing a mixture of ethanol, n-propanol and water with a water content comprised between 30 and 75% by weight with respect to the total weight of the mixture and the effluent is sent into the dehydration unit.

11. Process according to claim 1 in which the mixture containing ethanol and n-propanol originates from a hydrogenation of ethyl propanoate.

12. Process according to claim 11 , in which the ethyl propanoate is obtained by esterification of propanoic acid with ethanol, the propanoic acid and the ethanol being of biological origin.

13. Process according to claim 1 , in which the bringing into contact of stage a) is carried out in at least one reactor at a temperature comprised between 350 and 450° C., at a total pressure comprised between 0.2 and 1 MPa, and with a weight hourly space velocity (whsv) comprised between 2 and 8 h −1 .

14. Process according to claim 1 in which stage a) is carried out in two adiabatic reactors in series.

15. The process according to claim 4 has a mean mesopore diameter of between 7 and 11 nm.

16. The process according to claim 13 wherein at least one reactor is at a temperature at 375 and 425° C., at a total pressure comprised between 0.2 and 1 MPa.

17. The process according to claim 13 wherein at least one reactor is at a pressure between 0.2 and 0.7 MPa.

Assignees

• Ifp Energies Now
• Total Res & Technology Feluy

Inventors

• Aribert Nicolas
• Brandhorst Laure
• Coupard Vincent
• Maury Sylvie
• Vivien Tom

Classifications

• C07C31/10

  containing three carbon atoms · CPC title

• C07C11/06

  Propene · CPC title

• C07C67/08

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

• C07C31/08

  Ethanol · CPC title

• C07C2521/04

  Alumina · CPC title