초록 ▼

Mixed matrix membranes capable of separating carbon dioxide from mixtures including carbon dioxide and methane, and processes for purifying methane using the membranes, are disclosed. The membranes are polymer membranes with a selective layer thickness of between about 1000 Angstroms to about 0.005

Mixed matrix membranes capable of separating carbon dioxide from mixtures including carbon dioxide and methane, and processes for purifying methane using the membranes, are disclosed. The membranes are polymer membranes with a selective layer thickness of between about 1000 Angstroms to about 0.005 inch, that include discrete carbon-based molecular sieve particles with sizes of between about 0.5 microns to about 5.0 microns. The preferred ratio of particles to polymer is about 20% to about 50% by volume. A preferred method for preparing the mixed matrix membrane is by dispersing the particles in a solvent, adding a small quantity of the desired polymer or "sizing agent" to "size" or "prime" the particles, adding a polymer, casting a film of the polymer solution, and evaporating the solvent to form a mixed matrix membrane film. The mixed matrix membrane film permits passage of carbon dioxide and methane, but at different permeation rates, such that the ratio of the relative permeation rates of carbon dioxide to methane is larger through the mixed matrix membrane film than through the original polymer. The polymer is preferably a rigid, glassy polymer, more preferably, with a glass transition temperature above about 150° C. The mixed matrix membrane is preferably in the form of a dense film or a hollow fiber. A mixture containing carbon dioxide and methane can be enriched in methane by selective passage of carbon dioxide over methane in a gas-phase process through the membrane.

대표청구항 ▼

Mixed matrix membranes capable of separating carbon dioxide from mixtures including carbon dioxide and methane, and processes for purifying methane using the membranes, are disclosed. The membranes are polymer membranes with a selective layer thickness of between about 1000 Angstroms to about 0.005

Mixed matrix membranes capable of separating carbon dioxide from mixtures including carbon dioxide and methane, and processes for purifying methane using the membranes, are disclosed. The membranes are polymer membranes with a selective layer thickness of between about 1000 Angstroms to about 0.005 inch, that include discrete carbon-based molecular sieve particles with sizes of between about 0.5 microns to about 5.0 microns. The preferred ratio of particles to polymer is about 20% to about 50% by volume. A preferred method for preparing the mixed matrix membrane is by dispersing the particles in a solvent, adding a small quantity of the desired polymer or "sizing agent" to "size" or "prime" the particles, adding a polymer, casting a film of the polymer solution, and evaporating the solvent to form a mixed matrix membrane film. The mixed matrix membrane film permits passage of carbon dioxide and methane, but at different permeation rates, such that the ratio of the relative permeation rates of carbon dioxide to methane is larger through the mixed matrix membrane film than through the original polymer. The polymer is preferably a rigid, glassy polymer, more preferably, with a glass transition temperature above about 150° C. The mixed matrix membrane is preferably in the form of a dense film or a hollow fiber. A mixture containing carbon dioxide and methane can be enriched in methane by selective passage of carbon dioxide over methane in a gas-phase process through the membrane. powder contains about 30 to 40 tungsten, about 40 to 50 chromium, about 1.5 to 5 carbon, and the total cobalt plus nickel is about 15 to 25. 15. The corrosion resistant powder of claim 9 wherein the powder contains about 30 to 40 tungsten, about 45 to 50 chromium, about 3 to 5 carbon, and the total cobalt plus nickel is about 10 to 15. 16. A corrosion resistant coating having good wear resistance, the coating consisting essentially of, by weight percent, about 30 to 60 tungsten, about 27 to 60 chromium, about 1.5 to 6 carbon, a total of about 10 to 40 cobalt plus nickel and incidental impurities and melting point suppressants. 17. The corrosion resistant coating of claim 16 wherein the coating contains about 30 to 50 tungsten, about 1.5 to 5 carbon and about 30 to 50 chromium. 18. The corrosion resistant coating of claim 16 wherein the coating contains about 35 to 45 tungsten, about 30 to 40 chromium, about 3 to 5 carbon and the total cobalt plus nickel is about 15 to 25. 19. The corrosion resistant coating of claim 16 wherein the coating contains about 30 to 40 tungsten, about 40 to 50 chromium, about 1.5 to 5 carbon and the total cobalt plus nickel is about 15 to 25. 20. The corrosion resistant coating of claim 16 wherein the coating contains about 30 to 40 tungsten, about 45 to 50 chromium, about 3 to 5 carbon and the total cobalt plus nickel is about 10 to 15.