Abstract: This invention relates to membrane gas separation of carbon dioxide and methane containing gas mixtures. More particularly the invention relates to apparatus and processes for recovering a methane-enriched non-permeate gas of natural gas pipe line quality from mixtures of carbon dioxide and methane where membrane permeate gases contain substantially all of the carbon dioxide of the feed gas mixture. An aspect of the process of this invention is that a significant portion of the carbon dioxide containing permeate gas can be utilized as combustion engine fuel to drive feed gas compressors utilized in the process.

Abstract: A process for treating a landfill for recovering methane therefrom wherein a mixture of methane and carbon dioxide is withdrawn from a central portion of the landfill and the carbon dioxide and methane are separated. The methane is fed to a pipeline and a portion of the carbon dioxide is fed to wells spaced around the periphery of the landfill at a pressure of 7 to 170 kPa to prevent air from entering the landfill around the periphery thereof.

Abstract: A process for separating large percentages of aggressive gases such as carbon dioxide from low temperature gas mixtures wherein the gas mixture is passed through a plurality of treatment zones in series. In each treatment zone the gas mixture is first compressed to a pressure such that the partial pressure of the carbon dioxide is not greater than the critical carbon dioxide partial pressure and the compressed gas mixture is then brought into contact with a membrane more permeable to carbon dioxide than other gases of the mixture such that carbon dioxide permeates the membrane to the other side thereof. The gas mixture is maintained in contact with the membrane a sufficient time to lower the partial pressure of the carbon dioxide in the non-permeated gas mixture to less than about 40 percent of said critical carbon dioxide partial pressure. The process is especially useful for separating carbon dioxide from methane and other gases.

Abstract: The performance of axially-fed permeators comprising an essentially fluid impermeable tubular shell containing a plurality of selectively permeable hollow fibers suitable for the selective permeation of at least one fluid in a fluid mixture containing at least one other component, wherein the hollow fibers are positioned in a tubular shell and are assembled in the form of an elongated bundle, is enhanced by providing at least one flow diverter in the bundle. The flow diverter comprises a region of a plurality of hollow fibers embedded in a solid wherein the cross-sectional area of the flow diverter which is transverse to the orientation of the hollow fibers is a minor portion of the transverse cross-section sectional area of the bundle sufficient to divert fluid flow within the bundle. Advantageously, the portion of the plurality of hollow fibers encompassed in the flow diverter is insufficient to significantly adversely affect the total available membrane surface area for the selective permeation.

Abstract: Essentially inorganic monolithic hollow fibers having a radially anisotropic internal void volume wall structure. Process for the production of such fibers. Apparatus and processes using such fibers.

Abstract: The performance of axially-fed permeators containing a plurality of selectively permeable hollow fibers suitable for the selective permeation of at least one fluid in a fluid mixture containing at least one other component, wherein the hollow fibers are positioned in the permeator to form an elongated bundle of hollow fibers, is enhanced by the use of means to longitudinally compact the bundle.

Abstract: Essentially inorganic monolithic hollow fibers having a radially anisotropic internal void volume wall structure. Process for the production of such fibers. Apparatus and processes using such fibers.

Abstract: Ammonia synthesis processes are disclosed which provide enhanced recovery of hydrogen from ammonia synthesis purge streams by selective permeation. The enhanced recovery of hydrogen can provide increased conversion of hydrogen values to ammonia. In the processes, a purge stream from an ammonia synthesis loop at a superatmospheric pressure is passed to at least two permeator stages in series. Each permeator stage contains a separation membrane which exhibits selective permeation of hydrogen as compared to the permeation of each of methane and argon. A total pressure differential is maintained across the thickness of the separation membrane to provide a driving force for the permeation of hydrogen across the separation membrane of each of the permeator stages. Hydrogen permeates through the membrane, and a hydrogen-rich permeating gas is obtained on a permeate exit side of each of the permeator stages. The permeating gas from each of the permeator stages is recycled to the ammonia synthesis reaction zone.

Abstract: Processes are disclosed for separating at least one gas from a gaseous feed mixture containing at least one other gas comprising passing the gaseous feed mixture to at least two permeator stages in series. Each permeator stage contains a separation membrane which has a feed side and a permeate exit side and exhibits selective permeation of the at least one gas as compared to the permeation of the at least one other gas of the gaseous mixture. A total pressure differential is maintained across the thickness of the separation membrane in each permeator stage to provide a driving force for the permeation of the at least one gas across the separation membrane. The ratio of total pressure on the feed side to total pressure on the permeate exit side of the separation membrane for at least one permeator stage is less than the ratio of total pressure on the feed side to total pressure on the permeate exit side of the separation membrane for at least one subsequent, i.e., downstream, permeator stage.

Abstract: Essentially inorganic monolithic hollow fibers having a radially anisotropic internal void volume wall structure. Process for the production of such fibers. Apparatus and processes using such fibers.