Carbonaceous adsorbent membranes for gas dehydration:

Patent # 6,004,374 containing 25 claims, issued 12/21/1999. A carbonaceous adsorbent membrane is prepared by contacting a hydrophobic carbonaceous adsorbent membrane with an aqueous solution of one or more oxidizing acids and one or more metals selected from the group consisting of copper (+2), chromium (+3), and nickel (+2). The treated membrane is rinsed and dried to yield a hydrophilic carbonaceous adsorbent membrane which is useful for removing water from water-containing gas mixtures.

 

Passivation carbonaceous adsorptive membranes:

Patent # 5,912,048 containing 8 claims, issued 06/15/1999. Porous carbonaceous adsorptive membranes are protected or passivated from surface degradation in moist air by oxidizing the surface at relatively mild conditions after initial preparation of the membrane by pyrolysis. Carbon dioxide is a preferred passivating gas. Contact of passivated membranes with moist air at ambient conditions unexpectedly improves membrane effectiveness in separating gas mixtures containing hydrogen and light hydrocarbons.

 

Hydrogen recovery by pressure swing adsorption integrated with adsorbent membranes:

Patent # 5,753,010 containing 29 claims, issued 05/19/1998. A method for increasing product recovery or reducing the size of steam methane reformer and pressure swing adsorption systems utilized for hydrogen production. A significant portion of the hydrogen in the PSA depressurization and purge effluent gas, which is otherwise burned as fuel in the reformer, is recovered and recycled to the PSA system to provide additional high purity hydrogen product. This is accomplished by processing selected portions of the depressurization and purge effluent gas in adsorbent membrane separators to increase hydrogen content for recycle to the PSA system. Remaining portions of the depressurization and purge effluent gas, which contain lower concentrations of hydrogen, are utilized for fuel value in the reformer.

 

Composite porous carbonaceous membranes:

Patent # 5,507,860 containing 2 claims, issued 04/16/1996. 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.

 

Hydrogen recovery by adsorbent membranes:

Patent # 5,507,856 containing 8 claims, issued 04/16/1996. A composite semipermeable membrane comprising microporous adsorbent material supported by a porous substrate is utilized to separate hydrogen-hydrocarbon mixtures and a sweep gas comprising some of the same hydrocarbons is passed across the low pressure side of the membrane to enhance hydrocarbon permeability. Methane is an effective sweep gas which promotes the permeation of heavier hydrocarbons even when methane is present in the membrane feed.

 

Hydrogen recovery by adsorbent membranes:

Patent # 5,447,559 containing 2 claims, issued 09/05/1995. A composite semipermeable membrane comprising microporous adsorbent material supported by a porous substrate is operated in series with a pressure swing adsorption (PSA) system and the PSA reject gas is used as a sweep gas to improve membrane performance. The integrated membrane-PSA system is particularly useful for recovering high-purity hydrogen from a mixture of hydrogen and hydrocarbons, and is well-suited for integration with a steam-methane reformer.

 

Method of making composite porous carbonaceous membranes:

Patent # 5,431,864 containing 22 claims, issued 07/11/1995. 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.

 

Hydrogen recovery by adsorbent membranes:

Patent # 5,354,547 containing 14 claims, issued 10/11/1994. A composite semipermeable membrane comprising microporous adsorbent material supported by a porous substrate is operated in series with a pressure swing adsorption (PSA) system and the PSA reject gas is used as a sweep gas to improve membrane performance. The integrated membrane-PSA system is particularly useful for recovering high-purity hydrogen from a mixture of hydrogen and hydrocarbons, and is well-suited for integration with a steam-methane reformer.

 

Hydrocarbon fractionation by adsorbent membranes:

Patent # 5,332,424 containing 17 claims, issued 07/26/1994. A method is disclosed for separating a multicomponent gas mixture comprising at least three components into three product streams by use of adsorbent membrane zones operating in series. Each product is enriched in a different component based upon the relative strength of adsorption of each component on the adsorbent material. A non-permeate primary component product is obtained by the selective adsorption and permeation through the adsorbent membranes of secondary components which are more strongly adsorbed than the primary components in the gas mixture. Two or more permeate streams enriched in the more strongly adsorbed components are withdrawn from the membrane zones as individual secondary products, each of which contains a different component distribution determined by the relative strength of adsorption of the secondary components on the adsorbent material. Increased recovery and product purity are realized by the integration of pressure swing adsorption (PSA) and cryogenic separation systems with the adsorbent membrane zones. PSA reject gas is used as a membrane sweep gas to increase the permeation rates of secondary components.

 

Gas separation by adsorbent membranes:

Patent # 5,104,425 containing 19 claims, issued 04/14/1992. Composite semipermeable membranes comprising porous adsorptive material supported by a porous substrate are disclosed for use in a process for the separation of multicomponent gas mixtures. In the process, one or more primary components adsorb within the pores of the adsorptive material and diffuse by surface flow through the membrane to yield a permeate stream enriched in one or more of the primary components. Methods for making the composite membranes are described.  <![endif]>

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