US5431864A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making composite porous carbonaceous membranes
Assignee: Mid-America Commercialization Corp
•
Filing: 1994-04-18
•
Granted: 1995-07-11
•
Expires: 2014-04-18
Abstract
Abstract Improved composite semipermeable membranes including microporous carbonaceous adsorptive material supported by a porous substrate for use in separating multicomponent gas mixtures in which certain components in the mixture adsorb within the pores of the adsorptive material and diffuse by surface flow through the membrane to yield a permeate stream enriched in these components. Methods for making the improved composite membranes are described including one or more oxidation steps which increase the membrane permeability and selectivity.
Inventors
- 👤 Madhukar B. Rao
- 👤 Shivaji Sircar
- 👤 Timothy C. Golden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:13
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/28; B01J20/28014; B01J20/28033; B01D; B01D53/00; B01D53/22; B01D53/228; B01D67/00; B01D67/0039; B01D67/0067; B01D67/0081; B01D67/0088; B01D69/00; B01D69/10; B01D69/108; B01D69/12; B01D69/14; B01D69/141; B01D69/1411; B01D71/00; B01D71/02; B01D71/021; B01J20/28026; B01J20/28054; B01J20/28078; B01J20/2808; B01J20/28095; B01J20/28097; C; C04; C04B; C04B38/00; C04B38/0022; C04B41/00; C04B41/45; C04B41/50; C04B41/5001; C04B41/80; C04B41/81; C04B41/85; C10; C10G; C10G70/00; C10G70/04; C10G70/045; B01D2323/00; B01D2323/08; B01D2323/081; B01D2325/00; B01D2325/04; Y; Y10; Y10S; Y10S264/00; Y10S264/48; Y10S55/00; Y10S55/05
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
193 words
A method for making a composite semipermeable membrane for the separation of a multicomponent fluid mixture containing one or more primary components and one or more secondary components comprising the steps of: (a) coating a surface of an inert porous substrate with a layer of an organic precursor material; (b) heating the resulting coated porous substrate in an inert atmosphere to a first temperature and holding the coated porous substrate at this first temperature for a time sufficient to convert said organic precursor material into a layer of microporous carbonaceous adsorptive material to form a composite membrane; (c) cooling the resulting composite membrane to a temperature below said first temperature; (d) heating the composite membrane to a second temperature; (e) oxidizing the heated composite membrane at said second temperature in an oxidizing atmosphere selected from the group consisting of air, oxygen, carbon oxides, nitrogen oxides, steam, and mixtures thereof; and (f) cooling the resulting oxidized composite membrane to a temperature below said second temperature to form the composite semipermeable membrane; wherein said microporous carbonaceous adsorptive material can selectively adsorb portions of the primary components which diffuse through the membrane by selective surface flow.
Claim 2
Independent Claim
193 words
A method for making a composite semipermeable membrane for the separation of a multicomponent fluid mixture containing one or more primary components and one or more secondary components comprising the steps of: (a) coating a surface of an inert porous substrate with a layer of an organic precursor material; (b) heating the resulting coated porous substrate in an inert atmosphere to a first temperature and holding the coated porous substrate at this first temperature for a time sufficient to convert said organic precursor material into a layer of microporous carbonaceous adsorptive material to form a composite membrane; (c) cooling the resulting composite membrane to a temperature below said first temperature; (d) heating the composite membrane to a second temperature; (e) oxidizing the heated composite membrane at said second temperature in an oxidizing atmosphere selected from the group consisting of air, oxygen, carbon oxides, nitrogen oxides, steam, and mixtures thereof; and (f) cooling the resulting oxidized composite membrane to a temperature below said second temperature to form the composite semipermeable membrane; wherein said microporous carbonaceous adsorptive material can selectively adsorb portions of the primary components which diffuse through the membrane by selective surface flow.
Claim 3
Dependent Claim
15 words
The method of claim 1 further comprising repeating steps (a) through (c) at least once.
Claim 4
Dependent Claim
30 words
The method of claim 1 which further comprises repeating steps (d) through (f) one or more cycles, wherein the temperature of step (f) is ambient temperature in the last cycle.
Claim 5
Dependent Claim
18 words
The method of claim 3 wherein the duration of step (e) is between about 0.25 and 12 hours.
Claim 6
Dependent Claim
31 words
The method of claim 3 wherein steps (d) through (f) are repeated through two to four cycles, and wherein the temperature of step (f) is ambient temperature in the last cycle.
Claim 7
Dependent Claim
22 words
The method of claim 3 wherein step (e) is carried out at a temperature of between about 200° C. and 950° C.
Claim 8
Dependent Claim
27 words
The method of claim 1 wherein said organic precursor material is selected from the group consisting of polyvinylidene chloride, polyvinyl chloride, polyacrylonitrile, styrene-divinylbenzene copolymers, and mixtures thereof.
Claim 9
Dependent Claim
22 words
The method of claim 1 wherein the thickness of said layer of microporous carbonaceous adsorptive material is less than about 20 microns.
Claim 10
Dependent Claim
40 words
The method of claim 1 wherein said porous substrate has a distribution of pore diameters between about 0.2 and 50 microns and is selected from the group consisting of ceramics materials, carbonaceous materials, metallic materials, polymeric materials and combinations thereof.
Claim 11
Dependent Claim
49 words
The method of claim 1 wherein said coated porous substrate is heated in said inert atmosphere to said first temperature of between about 600° C. and 1200° C. at a heating rate of up to about 1.0° C. per minute to form said layer of microporous carbonaceous adsorptive material.
Claim 12
Independent Claim
185 words
A method for making a densified composite semipermeable membrane for the separation of a multicomponent fluid mixture containing one or more primary components and one or more secondary components comprising the steps of: (a) introducing an organic precursor material into the pores of an inert porous substrate; (b) heating said porous substrate containing said organic precursor to a first temperature and maintaining this first temperature for a sufficient time to convert the organic precursor material to microporous carbonaceous adsorptive material within said pores to form a composite membrane; (c) cooling the resulting composite membrane to a temperature below said first temperature; (d) heating the composite membrane to a second temperature; (e) oxidizing the heated composite membrane at said second temperature in an oxidizing atmosphere selected from the group consisting of air, oxygen, carbon oxides, nitrogen oxides, steam, and mixtures thereof; and (f) cooling the resulting oxidized composite membrane to a temperature below said second temperature to form the densified composite semipermeable membrane, wherein said microporous carbonaceous adsorptive material can selectively adsorb portions of the primary components which diffuse through the membrane by selective surface flow.
Claim 13
Independent Claim
185 words
A method for making a densified composite semipermeable membrane for the separation of a multicomponent fluid mixture containing one or more primary components and one or more secondary components comprising the steps of: (a) introducing an organic precursor material into the pores of an inert porous substrate; (b) heating said porous substrate containing said organic precursor to a first temperature and maintaining this first temperature for a sufficient time to convert the organic precursor material to microporous carbonaceous adsorptive material within said pores to form a composite membrane; (c) cooling the resulting composite membrane to a temperature below said first temperature; (d) heating the composite membrane to a second temperature; (e) oxidizing the heated composite membrane at said second temperature in an oxidizing atmosphere selected from the group consisting of air, oxygen, carbon oxides, nitrogen oxides, steam, and mixtures thereof; and (f) cooling the resulting oxidized composite membrane to a temperature below said second temperature to form the densified composite semipermeable membrane, wherein said microporous carbonaceous adsorptive material can selectively adsorb portions of the primary components which diffuse through the membrane by selective surface flow.
Claim 14
Dependent Claim
49 words
The method of claim 11 wherein said organic precursor material is a solution of a polymer in a suitable solvent, and wherein said heating to a first temperature evaporates said solvent thus depositing the polymer within said pores and carbonizes the polymer to yield said microporous carbonaceous adsorptive material.
Claim 15
Dependent Claim
25 words
The method of claim 12 wherein said polymer is selected from the group consisting of polyvinylidene chloride, polyvinyl chloride, polyacrylonitrile, styrene-divinylbenzene copolymers, and mixtures thereof.
Claim 16
Dependent Claim
27 words
The method of claim 12 wherein said solvent is selected from the group consisting of toluene, tetrahydrofuran, dimethyl formamide, dimethyl sulfoxide, acetone, and benzene and its derivatives.
Claim 17
Dependent Claim
45 words
The method of claim 11 wherein said organic precursor material is a hydrocarbon fluid, and wherein said heating to a first temperature promotes vapor phase thermal cracking of hydrocarbon components in said hydrocarbon fluid, whereby carbon is deposited within said pores of said porous substrate.
Claim 18
Dependent Claim
28 words
The method of claim 15 wherein said hydrocarbon fluid comprises one or more hydrocarbons selected from the group consisting of alkanes, alkenes, benzene, benzene derivatives, and mixtures thereof.
Claim 19
Dependent Claim
40 words
The method of claim 11 wherein said porous substrate has a distribution of pore diameters between about 0.2 and 50 microns and is selected from the group consisting of ceramic materials, carbonaceous materials, metallic materials, polymeric materials and combinations thereof.
Claim 20
Dependent Claim
15 words
The method of claim 11 further comprising repeating steps (a) through (c) at least once.
Claim 21
Dependent Claim
30 words
The method of claim 11 which further comprises repeating steps (d) through (f) one or more cycles, wherein the temperature of step (f) is ambient temperature in the last cycle.
Claim 22
Dependent Claim
18 words
The method of claim 19 wherein the duration of step (e) is between about 0.25 and 12 hours.
Claim 23
Dependent Claim
31 words
The method of claim 19 wherein steps (d) through (f) are repeated through two to four cycles, and wherein the temperature of step (f) is ambient temperature in the last cycle.
Claim 24
Dependent Claim
21 words
The method of claim 19 wherein step (e) is carried out at a temperature of between about 200° and 950° C.
References Cited (Backward Citations)
US4888033A
Cited
US4371454A
Cited
US4699892A
Cited
US4583996A
Cited
US4740219A
Cited
US4640901A
Cited
US4909989A
Cited
US4775655A
Cited
US4865630A
Cited
US4880765A
Cited
US4853001A
Cited
US4925459A
Cited
US4999330A
Cited
US4828588A
Cited
US4971696A
Cited
US5104425A
Cited
JPH03161030A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-07-10 | 1999-01-09 | 1999-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-10 | 2003-01-09 | 2003-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-10 | 2007-01-09 | 2007-07-11 | $7700.00 | Window Closed / Lapsed |