A method for separating a raw feed gas stream using a plurality of membrane module stages. The raw feed gas stream may be from a biogas process. Off-gas from another unit process in the system, such as a temperature swing adsorption unit or liquefaction unit, may be used as a low pressure sweep gas on the low pressure side of at least one of the membrane module stages. In one example, the sweep gas is used in a first membrane module stage. In another example, a stripping membrane module stage is provided and the sweep gas is used in the stripping membrane module stage. Optionally, portions of the off-gas could be directed to other streams in the system for the purpose of balancing compressor power requirements.

A device for separating a gas stream which has a compressor and three membrane separation units in series, connected to pass the retentate stream of each of the first two units to the subsequent membrane separation unit, comprises conduits for recycling the permeate streams of the second and the third membrane separation unit to upstream of the compressor and a control device controlling the fraction of the second permeate stream which is recycled. Adjusting which fraction of the second permeate is recycled can be used to maintain a target composition of the retentate obtained in the third membrane separation unit when the flow rate or the composition of the gas stream changes.

The present invention provides a gas separation system suitable for reducing energy required to separate a gas mixture. A gas separation system of the present invention includes: a first separation membrane unit that separates a gas mixture containing carbon dioxide and nitrogen into a first permeated gas and a first non-permeated gas; a second separation membrane unit that separates the first permeated gas into a second permeated gas and a second non-permeated gas; a first decompression device that decompresses a permeation-side space of the first separation membrane unit; and a second decompression device that decompresses a permeation-side space of the second separation membrane unit.

There is provided a process for effecting separation of an operative material from a gaseous feed material via a membrane that includes a polymeric phase and a liquid phase, comprising: over a first time interval, within a first apparatus, separating a first fraction of the operative material in response to permeation of the first fraction of the operative material through the membrane, with effect that residual material, including unseparated operative material is discharged and, within a second apparatus, from the residual material, separating a second fraction of the operative material in response to permeation of the second fraction of the operative material through the membrane; and after the first time interval, disposing a liquid material relative to the membrane of the first apparatus, such that a first fraction of the liquid material replenishes the liquid phase of the membrane of the first apparatus, and residual liquid material is collected by a redistributor and redistributed such that the residual liquid material becomes disposed relative the membrane of the second apparatus, such that a second fraction of the liquid material replenishes the liquid phase of the membrane of the second apparatus.

In a device for separating methane from a gas mixture containing methane, carbon dioxide and hydrogen sulfide, comprising a gas compressor, two or three membrane separation stages downstream of the compressor and a hydrogen sulfide adsorber, comprising a bed of activated carbon having catalytic activity for oxidizing hydrogen sulfide with oxygen, arranged upstream of the membrane separation stages, oxygen content and relative humidity can be adjusted for optimum adsorption capacity of the hydrogen sulfide adsorber by recycling permeate from the second membrane separation stage, which receives the retentate of the first membrane separation stage, to a point upstream of the hydrogen sulfide adsorber.

Membrane-based hydrogen purifiers having graphite frame members. The purifiers include a hydrogen-separation membrane module with at least one membrane cell containing at least one hydrogen-selective membrane, which includes a permeate face and an opposed mixed gas face, and a fluid-permeable support structure that physically contacts and supports at least a central region of the permeate face. The membrane cell further includes a permeate-side frame member and a mixed gas-side frame member. The permeate-side frame member is interposed between the hydrogen-selective membrane and the fluid-permeable support structure to physically contact a peripheral region of the permeate face and a peripheral region of the fluid-permeable support structure. The mixed gas-side frame member physically contacts a peripheral region of the mixed gas face. At least one of the permeate-side frame member and the mixed gas-side frame member is a graphite frame member.

Disclosed herein is a gas separation section for separating a first gas from one or more other gasses in a separation device, the gas separation section comprising: a first membrane that is substantially planar; a second membrane that is substantially planar; a first substrate that has a first surface and a second surface, wherein the second surface of the first substrate is on an opposite side of the first substrate than the first surface of the first substrate; a second substrate that has a first surface and a second surface, wherein the second surface of the second substrate is on an opposite side of the second substrate than the first surface of the second substrate; and a mesh that is arranged between the second surface of the first substrate and the second surface of the second substrate; wherein: the first substrate and the second substrate are sintered plates; the first membrane is on the first surface of the first substrate; the second membrane is on the first surface of the second substrate; the first and second membranes are both permeable by at least a first gas and not permeable by one or more other gasses; the thickness of the first membrane in a direction orthogonal to the plane of the first membrane is less than 10 micrometres; and the thickness of the second membrane in a direction orthogonal to the plane of the second membrane is less than 10 micrometres. Embodiments provide an improved gas separation device over known techniques. Advantages of the separation device according to embodiment include improved performance, easy implementation, a modular design and a scalable design.

An apparatus utilizes a membrane unit to capture components from atmospheric air, including carbon dioxide, enriches the carbon dioxide concentration, and delivers the enriched concentration of carbon dioxide to a sequestering facility. The membrane is configured such that as a first gas containing oxygen, nitrogen and carbon dioxide is drawn through the membrane, a permeate stream is formed where the permeate stream has an oxygen concentration and a carbon dioxide concentration higher than in the first gas and a nitrogen concentration lower than in the first gas. A permeate conduit, having a vacuum applied to it by a vacuum generating device receives the permeate stream and a delivery conduit delivers at least a portion of the enriched carbon dioxide to a sequestering facility. The apparatus may comprise a component of a system where the system may have a flue gas generator and/or a secondary enrichment system disposed between the vacuum generating device and the sequestering facility.

A dehumidification mechanism for an appliance includes a blower that delivers humid process air along an airflow path. A drum is positioned along the airflow path. A condensing apparatus dehumidifies the humid air to define dehumidified air. A membrane has a plurality of nanopores that define a portion of the airflow path within the condensing apparatus. The humid air is delivered along the membrane having the plurality of nanopores and the nanopores operate through capillary condensation to dehumidify the humid air and separate condensate away from the humid air to define the dehumidified air. The condensate removed by the nanopore membrane is delivered away from the airflow path and to a condensate collection area within the appliance.

A system for producing steam includes a steam generator with steam output; a membrane filtration system in fluid communication with the steam output and including a membrane filter with a permeate side and an opposing retentate side. The membrane filter includes a separation membrane constructed to reject organic molecules. The system may be used for removing organic compounds, such as anti-corrosion agents or contaminants, from steam.