The present disclosure describes a system and method for maintaining oxygen purity in portable oxygen concentrators, even with asymmetric generation of oxygen enriched gas volumes from different sieve beds of the concentration system. The present system and method compensate for asymmetric oxygen enriched gas generation using asymmetric delivery of purge volumes. Purge valves are used to deliver the asymmetric purge gas volumes, enables the system to maintain oxygen purity without additional power consumption, even when a portable oxygen concentrator does not include a product tank. The present system and method are configured such that asymmetry in enriched oxygen generation can be monitored and the asymmetric purge gas compensation can be applied independently from other control mechanisms of a portable oxygen concentrator.

A pressure swing adsorption air dryer system and method is described herein. In some embodiments, the air dryer system receives moist air and dries the air using a desiccant in a pressure swing adsorption method. The resulting dry air may be used as a working fluid for an application and a portion of the dry air may be used to aid in regenerating, or removing moisture from a desiccant. Sensors are strategically placed throughout the air drying system to measure the state of the air. The air and airflow may be controlled throughout the system based on the sensor measurements.

Disclosed herein is a stator plate for a rotary bed PSA apparatus that has an exhaust slot that has first and second sections for receiving blowdown and purge exhaust gas streams, the sections being separated by a flow restriction that restricts but does not full prevent gas flow between the sections, or that has separate exhaust slots for separately receiving the blowdown and purge exhaust gas streams. Also disclosed is pressure swing adsorption (PSA) apparatus including such a stator plate, and a rotary bed PSA process using such an apparatus.

Disclosed herein are rapid cycle pressure swing adsorption (PSA) process for separating O.sub.2 from N.sub.2 and/or Ar. The processes use a carbon molecular sieve (CMS) adsorbent having an O.sub.2/N.sub.2 and/or O.sub.2/Ar kinetic selectivity of at least 5 and an O.sub.2 adsorption rate (1/s) of at least 0.2000 as determined by linear driving force model at 1 atma and 86 F.

A method for separating at least one hydrocarbon from a feed containing a mixture of at least one hydrocarbon and nitrogen, comprising contacting the feed with an adsorbent comprising a porous support wherein the porous support comprises exchangeable cations and at least a portion of the exchangeable cations are organic cations.

Provided are apparatus and systems for performing a swing adsorption process. This swing adsorption process may involve performing a startup mode process prior to beginning a normal operation mode process to remove contaminants from a gaseous feed stream. The startup mode process may be utilized for swing adsorption processes, such as TSA and/or PSA, which are utilized to remove one or more contaminants from a gaseous feed stream.

Provided are apparatus and systems for performing a swing adsorption process. This swing adsorption process may involve performing a startup mode process prior to beginning a normal operation mode process to remove contaminants from a gaseous feed stream. The startup mode process may be utilized for swing adsorption processes, such as TSA and/or PSA, which are utilized to remove one or more contaminants from a gaseous feed stream.

The present disclosure relates to a pressure swing adsorption apparatus for hydrogen purification from decomposed ammonia gas and a hydrogen purification method using the same, and more particularly, the pressure swing adsorption apparatus of the present disclosure includes a plurality of adsorption towers including a pretreatment unit and a hydrogen purification unit wherein the adsorption towers of the pretreatment unit and the hydrogen purification unit are packed with different adsorbents, thereby achieving high purity hydrogen purification from mixed hydrogen gas produced after ammonia decomposition, making it easy to replace the adsorbent for ammonia removal, minimizing the likelihood that the lifetime of the adsorbent in the hydrogen purification unit is drastically reduced by a very small amount of ammonia, and actively responding to a large change in ammonia concentration in the raw material.

Additionally, a hydrogen purification method using the pressure swing adsorption apparatus of the present disclosure physically adsorbs and removes impurities such as moisture (H.sub.2O), ammonia (NH.sub.3) and nitrogen (N.sub.2) included in mixed hydrogen gas produced after ammonia decomposition below extremely small amounts, thereby achieving high purity hydrogen purification with improved selective adsorption of moisture, ammonia and nitrogen and maximized hydrogen recovery rate and productivity. In addition, since the temperature swing adsorption process is not introduced, there is no need for a heat source for regeneration, thereby reducing the driving cost.

Systems and methods are provided for integrating direct air capture of carbon dioxide with capture of carbon dioxide from a point source. The systems and methods can include exposing an adsorbent to a low CO.sub.2 content gas flow (e.g., air) at conditions similar to ambient conditions to perform an initial amount of sorption of CO.sub.2. The initial sorption results in a partially loaded sorbent having a first sorbent loading. The partially loaded sorbent can then be exposed to a flue gas and/or other gas flow that contains a higher CO.sub.2 content. This allows a second sorption step to be performed using a higher CO.sub.2 content gas, resulting in an additionally loaded sorbent having a second (higher) sorbent loading. The sorbed CO.sub.2 can then be desorbed from the sorbent.

An improved DAC unit and process containing an adsorber structure comprising an array of adsorber elements with a support layer and on both sides thereof at least one sorbent layer and at least one protective layer comprising a microporous material disposed around the support layer and the sorbent layer, wherein the protective layer has greater hydrophobicity than the sorbent material, wherein the adsorber elements are parallel to each other and spaced apart forming parallel fluid passages for flow-through of ambient atmospheric air and/or desorbing media, the method comprising the following sequential and repeating steps: (a) adsorption by flow-through; (b) isolating said sorbent; (c) injecting a stream of desorbing media through said parallel fluid passages and inducing an increase of the temperature; (d) extracting desorbed carbon dioxide from the unit and separating it from desorbing media; (e) bringing the sorbent material to ambient temperature conditions.