Alumina-based adsorbent containing sodium and doped with an alkali element for capturing acidic molecules

Patent metadata

Field	Value
Publication number	US-2017225144-A1
Application number	US-201515500843-A
Country	US
Kind code	A1
Filing date	Jun 22, 2015
Priority date	Jul 31, 2014
Publication date	Aug 10, 2017
Grant date	—

Abstract

The present invention relates to an adsorbent comprising an alumina support and at least one alkali element, said adsorbent being obtained by introducing at least one alkali element, identical to or different from sodium, onto an alumina support the sodium content of which, expressed as Na 2 O equivalent, before the introduction of the alkali element or elements, is comprised between 1000 and 5000 ppm by weight with respect to the total weight of the support. The invention also relates to processes for the preparation of said adsorbent and use thereof in a process for the elimination of acidic molecules such as COS and/or CO 2 .

First claim

1 . Adsorbent comprising an alumina support and at least one alkali element, said adsorbent being obtained by the introduction of at least one alkali element, identical to or different from sodium, onto an alumina support the sodium content of which, expressed as Na 2 O equivalent, before the introduction of the alkali element or elements, is comprised between 1000 and 5000 ppm by weight with respect to the total weight of the support.

2 . Adsorbent according to claim 2 , in which the alkali element is selected from sodium and potassium.

3 . Adsorbent according to claim 1 , in which the content of alkali element with respect to the total weight of the adsorbent is comprised between 1 and 60% by weight of said element.

4 . Adsorbent according to claim 1 , in which the sodium content, expressed as Na 2 O equivalent, in the alumina support before the introduction of the alkali element or elements is comprised between 1500 and 3500 ppm by weight with respect to the total weight of the support.

5 . Adsorbent according to claim 1 , in which the alumina support before the introduction of the alkali element or elements has a total pore volume comprised between 0.3 and 1 cm 3 .g −1 and a specific surface area between 50 and 450 m 2 .g −1 .

6 . Adsorbent according to claim 1 , which is constituted by potassium and the alumina support having a sodium content, expressed as Na 2 O equivalent, before the introduction of the potassium, comprised between 1500 and 3500 ppm by weight with respect to the total weight of the support.

7 . Process for the preparation of the adsorbent as defined in claim 1 , comprising the following steps:
a) preparing an aqueous solution containing at least one alkali precursor, b) impregnating an alumina support having a sodium content, expressed as Na 2 O equivalent, comprised between 1000 and 5000 ppm by weight with respect to the total weight of the support, with the aqueous solution obtained at the end of step a), c) leaving the impregnated support originating from step b) to mature in a water-saturated closed vessel, d) drying the solid originating from step c).

8 . Process for the preparation of the adsorbent as defined in claim 1 , comprising the following steps:
a′) mixing an alumina support having a sodium content, expressed as Na 2 O equivalent, comprised between 1000 and 5000 ppm by weight with respect to the total weight of the support, with a powder of at least one alkali precursor, b′) optionally grinding the mixture obtained at the end of step a′) to a granulometry comprised between 2 and 100 μm, c′) forming the mixture originating from step b′) in the presence of water so as to obtain a material, d′) drying the formed material originating from step c′).

9 . Process for the preparation of the adsorbent as defined in claim 1 , comprising the following steps:
a″) mixing an alumina support having a sodium content, expressed as Na 2 O equivalent, comprised between 1000 and 5000 ppm by weight with respect to the total weight of the support, with a solution comprising at least one alkali precursor, in order to obtain a paste, b″) forming the paste obtained in step a″), c″) drying the formed paste originating from step b″).

10 . Process according to claim 7 , in which a calcination step is carried out in air in a dry or humid atmosphere at the end of the drying step.

11 . Process for the elimination of an acidic molecule from a hydrocarbon flow containing at least one acidic molecule, in which the hydrocarbon flow is brought into contact during an adsorption step with an adsorbent according to claim 1 .

12 . Elimination process according to claim 11 , in which the acidic molecule is COS and/or CO 2 .

13 . Elimination process according to claim 11 , in which the adsorption step is carried out at a temperature between −50 and 100° C., at an absolute pressure comprised between 0.01 MPa and 5 MPa and at an hourly space velocity comprised between 50 and 50000 h −1 .

14 . Elimination process according to claim 11 , in which a step of adsorbent regeneration is carried out once the adsorbent is at least partially saturated with acidic molecules.

15 . Elimination process according to claim 14 , in which the regeneration step is carried out by bringing the adsorbent, at least partially saturated with acidic molecules, into contact with a gas or a liquid at a temperature comprised between 20 and 500° C., at an absolute pressure comprised between 0.01 MPa and 5 MPa and at an hourly space velocity comprised between 50 and 50,000 h −1 .

Assignees

• Ifp Energies Now

Inventors

• Barthelet Karin
• Baudot Arnaud
• Lelias Marc-Antoine
• Ducreux Olivier

Classifications

• B01J20/3433

  of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425 · CPC title

• B01D2257/504

  Carbon dioxide · CPC title

• B01D2253/25

  Coated, impregnated or composite adsorbents · CPC title

• B01J20/3236

  containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts · CPC title

• B01J20/28059

  being less than 100 m2/g · CPC title