Potassium-merlinoite zeolite, its synthesis and use

Patent metadata

Field	Value
Publication number	US-11638909-B2
Application number	US-202217877626-A
Country	US
Kind code	B2
Filing date	Jul 29, 2022
Priority date	Aug 7, 2019
Publication date	May 2, 2023
Grant date	May 2, 2023

Abstract

The present disclosure is directed to processes for the selective separation of carbon dioxide (CO2) from multi-component feedstreams containing CO2. The processes use a potassium-form MER framework type zeolite having a stick-like morphology. The potassium is present in the zeolite as K+ in extra-framework locations, and the zeolite is essentially free of an extra-framework cation other than potassium.

First claim

The invention claimed is:

1. A process for separating CO 2 from a process feedstream, comprising:
(a) synthesizing a MER framework type zeolite by a method consisting essentially of:
(i) providing a reaction mixture comprising:
(1) a FAU framework type zeolite;
(2) a source of potassium cations associated with anions;
(3) a source of hydroxide ions; and
(4) water;

wherein the reaction mixture has a composition, in terms of molar ratios, as follows:
SiO 2 /Al 2 O 3 4 to 10, [K + ]/SiO 2 0.30 to 0.80, [OH − ]/SiO 2 0.30 to 0.80, and H 2 O/SiO 2 5 to 20; and
(ii) subjecting the reaction mixture to crystallization conditions sufficient to convert the FAU framework type zeolite to a potassium-form MER framework type zeolite, which is essentially free of an extra framework cation other than potassium;

(b) contacting an adsorbent bed comprising the synthesized potassium-form MER framework type zeolite of the step (a) with a process feedstream comprising CO 2 and a second component comprising one or more of CH 4 and N 2 at a first pressure and a first temperature;
(c) adsorbing at least a portion of the CO 2 in the adsorbent bed;
(d) producing a CO 2 -lean product stream, wherein the CO 2 -lean product stream has a lower concentration of CO 2 by vol. % than the process feedstream; and
(e) producing a CO 2 -rich product stream at a second pressure and a second temperature, wherein the CO 2 -rich product stream has a higher concentration of CO 2 by vol. % than the process feedstream;
wherein the potassium-form MER framework type zeolite has a stick-like morphology, the potassium is present as K + in extra-framework locations, and the potassium-form MER framework type zeolite is essentially free of an extra-framework cation other than potassium.

2. The process as in claim 1 , wherein the process feedstream is a natural gas, a flue gas, or a biogas.

3. The process as in claim 1 , wherein the synthesized potassium-form MER framework type zeolite is at least partially dehydrated at a temperature of at least 150° C.

4. The process of claim 1 , wherein the reaction mixture in the step (a) has a composition, in terms of molar ratios, as follows:
SiO 2 /Al 2 O 3 4 to 7, [K + ]/SiO 2 0.50 to 0.70, [OH − ]/SiO 2 0.50 to 0.70, and H 2 O/SiO 2 5 to 15.

5. A process for separating CO 2 from a process feedstream, comprising:
(a) synthesizing a MER framework type zeolite by a method consisting essentially of:
(i) providing a reaction mixture comprising:
(1) a FAU framework type zeolite;
(2) a source of potassium cations associated with anions;
(3) a source of hydroxide ions; and
(4) water;

wherein the reaction mixture has a composition, in terms of molar ratios, as follows:
SiO 2 /Al 2 O 3 4 to 10, [K + ]/SiO 2 0.30 to 0.80, [OH − ]/SiO 2 0.30 to 0.80, and H 2 O/SiO 2 5 to 20; and
(ii) subjecting the reaction mixture to crystallization conditions sufficient to convert the FAU framework type zeolite to a potassium-form MER framework type zeolite, which is essentially free of an extra framework cation other than potassium;
(b) contacting a first side of a membrane comprised of the synthesized potassium-form MER framework type zeolite of the step (a) with a process feedstream comprising CO 2 and a second component comprising one or more of CH 4 and N 2 at a first pressure and a first temperature;
(c) collecting a first permeate stream from a second side of the membrane at second pressure and a second temperature, wherein the first permeate stream consists of components that selectively permeate through the membrane and the first permeate stream has a higher concentration of CO 2 by vol. % than the process feedstream; and
(d) collecting a first retentate stream, wherein the first retentate stream has a lower concentration of CO 2 by vol. % than the process feedstream;

wherein the potassium-form MER framework type zeolite has a stick-like morphology, the potassium is present as K + in extra-framework locations, and the potassium-form MER framework type zeolite is essentially free of an extra-framework cation other than potassium.

6. The process as in claim 5 , wherein the process feedstream is a natural gas, a flue gas, or a biogas.

7. The process as in claim 5 , wherein the synthesized potassium-form MER framework type zeolite is at least partially dehydrated at a temperature of at least 150° C.

8. The process of claim 5 , wherein the reaction mixture in the step (a) has a composition, in terms of molar ratios, as follows:
SiO 2 /Al 2 O 3 4 to 7, [K + ]/SiO 2 0.50 to 0.70, [OH − ]/SiO 2 0.50 to 0.70, and H 2 O/SiO 2 5 to 15.

Assignees

• Chevron Usa Inc

Inventors

• Thompson Joshua Allen
• Xie Dan

Classifications

• B01D71/0281

  Zeolites · CPC title

• B01D2259/401

  using a single bed · CPC title

• B01D53/047

  Pressure swing adsorption · CPC title

• B01D53/0462

  Temperature swing adsorption · CPC title

• B01D2256/245

  Methane · CPC title