Composite carbon molecular sieve membranes having anti-substructure collapse particles loaded in a core thereof

• US 10,086,337 B2
• Filed: 08/14/2015
• Issued: 10/02/2018
• Est. Priority Date: 11/30/2014
• Status: Active Grant

• Current Assignee: L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Original Assignee: L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Inventors: Kratzer, Dean W., Kosuri, Madhava R., Ma, Canghai
• Primary Examiner(s): Greene, Jason M
• Application Number:
  US14/827,064
• Publication Number:
  US 20160151746A1
• Time in Patent Office: 1,145 Days
• CPC Class Codes: B01D 2053/224 with hollow fibres
• CPC Class Codes: B01D 2253/116 Molecular sieves other than zeolites
• CPC Class Codes: B01D 2323/18 Pore-control agents or pore formers
• CPC Class Codes: B01D 2325/02 Details relating to pores or porosity of the membranes
• CPC Class Codes: B01D 2325/0283 Pore size
• CPC Class Codes: B01D 2325/12 Adsorbents being present on the surface of the membranes or in the pores
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 53/229 Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption)
• CPC Class Codes: B01D 63/0232 using hollow fibers mats as precursor, e.g. wound or pleated mats
• CPC Class Codes: B01D 67/0067 by carbonisation or pyrolysis
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/08 Hollow fibre membranes manufacture of hollow fibres D01D5/24, D01F1/08
• CPC Class Codes: B01D 69/088 Co-extrusion; Co-spinning
• CPC Class Codes: B01D 71/021 Carbon
• CPC Class Codes: B01D 71/641 Polyamide-imides
• CPC Class Codes: B01D 71/643 Polyether-imides
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

A carbon molecular sieve (CMS) membrane is made by pyrolyzing, to a peak pyrolysis temperature T_P, a hollow fiber membrane having a polymeric sheath surrounding a polymeric core, anti-substructure collapse particles present in pores formed in the polymeric core help prevent collapse of pores formed in the hollow fiber membrane before pyrolysis. The anti-substructure collapse particles are made of a material or materials that either: i) have a glass transition temperature T_G higher than T_P, ii) have a melting point higher than T_P, or ii) are completely thermally decomposed during said pyrolysis step at a temperature less than T_P. The anti-substructure collapse particles are not soluble in a solvent used for dissolution of the polymeric material of the core.

Claims

1. A method for producing a CMS membrane fiber, comprising the steps of:

forming a composite precursor polymeric hollow fiber having a sheath covering a hollow core, the core being solidified from a core composition comprising essentially consisting of a polymeric core material dissolved in a core solvent or solvents, and silica particles insoluble in the core solvent or solvents, and optionally a pore former, the silica particles being disposed within pores formed in the polymeric core material, the sheath being solidified from a sheath composition comprising a polymeric sheath material dissolved in a sheath solvent, the silica particles having an average size of less than one micron, wherein there are no silica particles in the sheath; and

pyrolyzing the composite precursor polymeric hollow fiber up to a peak pyrolysis temperature TP, wherein the silica particles have a melting point higher than TP, wherein the core polymeric material is made of 6FDA;

BPDA/DAM and the sheath polymeric material is made of 6FDA;

BPDA/DAM.

2. The method of claim 1, wherein a wt % of the polymer or copolymer in the core composition is lower than a wt % of the polymer or copolymer in the sheath composition.

3. The method of claim 1, wherein a wt % of the silica particles in the core composition is selected such that the polymeric sheath material shrinks along a length of the fiber no more than +/−

15% than that of the polymeric core material, but in any case is at least 5 wt %.

4. A CMS membrane fiber produced according to the method of claim 1.

5. A CMS membrane module including a plurality of the CMS membrane fibers of claim 4.

6. A method for separating a gas mixture, comprising the steps of feeding a gas mixture to the CMS membrane module of claim 5, withdrawing a permeate gas from the CMS membrane module that is enriched in at least one gas relative to the gas mixture, and withdrawing a non-permeate gas from the CMS membrane module that is deficient in said at least one gas relative to the gas mixture.