Reactive inhibition of pore structure collapse during pyrolytic formation of carbon molecular sieves

Patent metadata

Field	Value
Publication number	US-11660575-B2
Application number	US-201916717788-A
Country	US
Kind code	B2
Filing date	Dec 17, 2019
Priority date	Dec 31, 2018
Publication date	May 30, 2023
Grant date	May 30, 2023

Abstract

Disclosed herein are carbon molecular sieves and methods of making the same through the pyrolysis of a polymer precursor in the presence of a reactive gas stream including a hydrogen source.

First claim

What is claimed is:

1. A process for controlling a pore structure of a carbon molecular sieve comprising:
providing a polymer precursor comprising a rigid microporous polymer;
heating the polymer precursor in a chamber to at least a temperature at which the polymer precursor undergoes pyrolysis; and
flowing a reactive gas stream through the chamber during the heating to control the pore structure of the carbon molecular sieve,
wherein the reactive gas stream comprises H 2 and the carbon molecular sieve comprising the polymer precursor.

2. The process of claim 1 , wherein the reactive gas stream further comprises an inert gas selected from a group consisting of argon, neon, N 2 , helium, and CO 2 or combinations thereof.

3. The process of claim 1 , wherein the reactive gas stream further comprises argon.

4. The process of claim 1 , wherein the temperature of the pyrolysis of the polymer precursor film is from 500° C. to 1500° C.

5. The process of claim 1 , wherein soak time of the pyrolysis of the polymer precursor film is from 30 min to 24 hours.

6. The process of claim 1 , wherein the reactive gas stream is a pure H 2 stream.

7. The process of claim 1 , wherein the H 2 is in a concentration of from 1 ppm to 4 vol. % of the reactive gas stream.

8. The process of claim 1 , wherein the polymer precursor comprises a rigid polymer.

9. The process of claim 1 , wherein the rigid microporous polymer is a polymer of intrinsic microporosity selected from a group consisting of PIM-1, PIM-7, PIM-8, PIM-9, KAUST-PI-1, PIM-BADAS-1, PIM-DUCKY-1, PIM-Tz 25 , PIM-DUCKY-2, PIM-BADAS-2, PIM-SADAS, and combinations thereof.

10. The process of claim 1 , wherein the carbon molecular sieve is utilized as a membrane, adsorbent, catalyst, composite or a filter.

11. The process of claim 1 , wherein the polymer precursor has a form factor of film, sheet fiber, hollow fiber, coated tube, coated disc, or coated monolith.

12. The process of claim 1 , wherein an inert gas stream flows through the chamber during the heating, wherein the inert gas stream comprises argon, and wherein flow rate of the inert gas stream is different from flow rate of the reactive gas stream.

13. The process of claim 1 , wherein the polymer precursor comprises PIM-1.

14. The process of claim 1 , wherein ramp rate of the process is from 0.1° C./min to 200° C./min.

15. The process of claim 1 , wherein cool down rate of the process is from 0.1° C./min to 200° C./min.

16. The process of claim 1 , wherein the reactive gas stream reacts with the polymer precursor to form H 2 O and/or CO 2 during pyrolysis.

17. The process of claim 1 , wherein the chamber comprises a fume hood comprising a tubular furnace, a quartz tube disposed at least partially inside of the tubular furnace, a mesh plate support disposed inside of the quartz tube, and the polymer precursor is disposed on the mesh plate support.

18. The process of claim 1 , wherein ultra-micropores of the carbon molecular sieve are selectively targeted by the pyrolysis to prevent collapse while leaving the micropores relatively unchanged.

19. The process of claim 1 , wherein the diffusion selectivity of the polymer precursor is enhanced while the sorption selectivity of the polymer precursor is essentially unchanged.

20. The process of claim 1 , wherein an H 2 concentration and/or pyrolysis temperature is selected to obtain a desired molecule permeance or perm-selectivity.

21. The process of claim 1 , wherein the polymer precursor is heated in a stepwise manner during the heating step.

22. The process of claim 1 , wherein the rigid microporous polymer is a polymer of intrinsic microporosity selected from a group consisting of PIM-8, PIM-9, KAUST-PI-1, PIM-BADAS-1, PIM-DUCKY-1, PIM-Tz 25 , PIM-DUCKY-2, PIM-BADAS-2, PIM-SADAS, and combinations thereof.

Assignees

• Exxonmobil Technology & Engineering Company
• Georgia Tech Res Inst

Inventors

• Ma Yao
• Jue Melinda
• Lively Ryan
• Bhandari Dhaval Ajit

Classifications

• B01J20/28059 Primary

  being less than 100 m2/g · CPC title

• C10G2300/1077

  Vacuum residues · CPC title

• B01D53/228

  characterised by specific membranes · CPC title

• C10G2300/1044

  Heavy gasoline or naphtha having a boiling range of about 100 - 180 °C · CPC title

• B01J20/3078

  Thermal treatment, e.g. calcining or pyrolizing · CPC title