A driving system for a reversing blower adsorption based air separation unit is configured to not only drive the reversing blower cyclically in a forward and in a reverse direction, but also to allow the reversing blower to coast during a portion of its operating cycle. While coasting, a pressure differential across the blower acts alone to switch the reversing blower between a forward and a reverse direction of operation. Less power is thus required. When coasting, the blower can also be configured to output power such as the drive motor functioning as an electric generator or by having a mechanical power input be driven by the blower for power generation and/or energy storage. Such a system beneficially utilizes the energy associated with the pressure differential across the blower for energy harvesting and to further accelerate cycle times for the reversing blower adsorption based air separation unit.

An air separation unit includes an air inlet with a reversible blower downstream therefrom and an adsorption bed filled with adsorption media downstream of the reversible blower. The adsorption bed contains an adsorption media which preferentially adsorbs nitrogen over oxygen. An oxygen and argon output is located downstream of the absorption bed. At least a portion of the mixed gas of oxygen and argon is routed to a modular argon separator which separates out at least a portion of the argon to provide high purity oxygen to a high purity oxygen outlet. The argon separator can be configured as a molecular sieve filter to separate the argon from the oxygen or the argon separator can be in the form of a gas cooler and condenser which condenses liquid oxygen for storage and discharge as substantially pure oxygen.

The adsorption based air separation unit includes an adsorber vessel containing media which selectively adsorbs water vapor and nitrogen preferentially over oxygen. The vessel includes an air entry spaced from an oxygen discharge. At least one dry air tap from the adsorber vessel is located between the entry and the discharge. When the adsorption media is fresh, air entering the adsorber vessel passes through enough of the adsorber vessel to have much of its water vapor removed and only some of its nitrogen removed. The vessel can include multiple taps sequentially further from the entry which can be selectively opened as the adsorption media becomes saturated with water vapor and nitrogen, so that dry air with much of its nitrogen still present can be further tapped from the adsorber vessel. The adsorber vessel thus facilitates production of both oxygen and dry air, such as for use as medical grade air.

Cavitand compositions that comprise void spaces are disclosed. The void spaces may be empty, which means that voids are free of guest molecules or atoms, or the void spaces may comprise guest molecules or atoms that are normally in their gas phase at standard temperature and pressure. These cavitands may be useful for industrial applications, such as the separation or storage of gasses. Novel cavitand compounds are also disclosed.

Polymer membranes include a polymer material that is selectively permeable to acidic gases over methane in a gas stream, such as natural gas. The polymer material may be a polymer membrane comprising a fluorinated polytriazole polymer. The fluorinated polytriazole polymer may further comprise a substituted phenyl or a substituted benzenaminyl. The substituted phenyl or substituted benzenaminyl may be substituted with hydrogen, bromo, fluoro, chloro, iodo, hydroxy, methyl, trifluoromethyl, dimethylamino, tert-butyl, or difluoromethoxy groups. The polymer material may have a degree of polymerization of from 100 to 175. The polymer membranes may be incorporated into systems or methods for removing separable gases, such as acidic gases, from gas streams, such as natural gas.

A moderate pressure, argon and nitrogen producing cryogenic air separation unit and air separation cycle having a higher pressure column, a lower pressure column and an argon column arrangement is disclosed. The moderate pressure, argon and nitrogen producing cryogenic air separation unit is configured to take a first portion of an oxygen enriched stream from the lower pressure column, which together with an external source of liquid nitrogen is used as the boiling side refrigerant to condense the argon in the argon condenser. Use of the external source of liquid nitrogen in the argon condenser allows a second portion of the oxygen enriched stream from the lower pressure column to be taken as a liquid oxygen product stream.

Some embodiments of the disclosure correspond to, for example, a method for controlling a scrubber containing an adsorbent. The scrubber may be configured to cycle between scrubbing at least one pollutant/gas from a stream of gases with the pollutant/gas being adsorbed onto the adsorbent, and regenerating at least some of the adsorbent and thereby purging at least some of the one pollutant and/or first gas from the adsorbent via a regeneration gas flow. The method may include flowing a stream of gases through the scrubber, the scrubber including the adsorbent and adsorbing at least some of the one pollutant/gas from the stream of gases onto the adsorbent during an adsorption phase over a first time period. The method may also include purging at least a portion of the one pollutant/gas from the adsorbent during a regeneration phase over a second time period with a regeneration gas flow, and cycling therebetween.

A multistage membrane system and a process for treating a gas stream is provided in which the multistage membrane system comprises at least two membrane units wherein a first stage membrane unit comprises a polymeric membrane and a second membrane unit comprises a microporous zeolitic inorganic membrane or a combination of a microporous zeolitic inorganic membrane and a polymeric membrane.

Methods of producing a hydrogen-enriched product and recovering CO.sub.2 are described. A synthesis gas stream from a hydrogen production process unit is separated in a hydrogen pressure swing adsorption unit into a high-pressure hydrogen stream and a hydrogen depleted tail gas stream, and the hydrogen depleted tail gas stream is compressed. The compressed tail gas stream is separated in a CO.sub.2 fractionation system into a CO.sub.2-enriched product stream and an overhead stream. The overhead stream is separated in an overhead hydrogen PSA system into a second high-pressure hydrogen stream and a low-pressure tail gas stream. The first and second high-pressure hydrogen streams and the CO.sub.2-enriched product stream are recovered. The low-pressure tail gas stream from the overhead hydrogen PSA system is combusted with oxygen to produce steam, electricity, or both.

A gas separation method in which a rare as a first introduced gas and an impurity gas as a second introduced gas, are introduced into a raw material gas. Each of the flow rates of the first and second introduced gases is controlled based on the flow rates of the rare gas and impurity gas in the discharged gas from a rare gas using facility. A gas separation device includes an introduction pipe for introducing rare gas in a separation gas container into a raw material gas, an introduction pipe for introducing impurity gases in the separation gas container into the raw material gas, a flow meter provided in a supply pipe for supplying a discharged gas of a rare gas using facility, and an arithmetic device electrically connected to each of the flow meter the flow rate controller, and the flow rate controller.