Methods and systems for capture of CO.sub.2 from a hydrated gaseous stream are described. Systems can be utilized for direct air capture of CO.sub.2 and incorporate a low energy temperature-vacuum swing adsorption (TVSA) process. A TVSA process can include a multi-step CO.sub.2 capture bed regeneration process that includes depressurization of the bed, heating of the bed, venting and purging of the bed, and cooling of the bed. Multiple beds can be cycled between CO.sub.2 capture and regeneration, during which captured CO.sub.2 is recovered. Off-gas from a CO.sub.2 capture bed can be used in regenerating a parallel bed for increased efficiency.

The present disclosure provides a method for a mobile pressure swing adsorption oxygen production device, comprising a first PSA section, a second PSA section and a third PSA section which are operated in series; the first PSA section adsorbs oxygen in raw air by a velocity-selective adsorbent; the second PSA section adsorbs nitrogen etc. in desorption gas of the first PSA section by a nitrogen balance-selective adsorbent; the third PSA section removes nitrogen from oxygen-rich gas flowing out of the second PSA section; the first PSA section sequentially undergoes at least adsorption A and vacuumizing VC in one cycle; the second PSA section sequentially undergoes at least adsorption A, pressure-equalizing drop ED, backward discharge BD and pressure-equalizing rise ER; and the third PSA section sequentially undergoes at least adsorption A, pressure-equalizing drop ED, backward discharge BD and pressure-equalizing rise ER.

Methods and systems for continuous pressure swing adsorption separation of a pressurized feed gas stream, the method including separating hydrocarbons heavier than methane from the pressurized feed gas stream to produce at least two product streams, a first product stream being substantially pure methane, and a second product stream being substantially comprised of components with a greater molecular weight than methane.

According to an exemplary embodiment of the present invention, a pressure swing adsorption process of a hydrogen production system is provided.

The hydrogen production system comprises a desulfurization process for removing sulfur components from raw natural gas; a reforming reaction process for producing a reformed gas containing hydrogen generated by the reaction of natural gas through the desulfurization process and steam; and a pressure swing adsorption process of concentrating the hydrogen using a pressure swing adsorption from the reformed gas.

In a desorption step of the pressure swing adsorption process, a cocurrent depressurization and a countercurrent depressurization are simultaneously performed.

Methods and systems for continuous pressure swing adsorption separation of a pressurized feed gas stream, the method including separating hydrocarbons heavier than methane from the pressurized feed gas stream to produce at least two product streams, a first product stream being substantially pure methane, and a second product stream being substantially comprised of components with a greater molecular weight than methane.

A pressure swing adsorption gas production device that enables performing a desorption process in adsorption towers is provided. The device includes an off gas discharge route connected to the adsorption towers, a membrane separation unit with a separation membrane allowing miscellaneous gas in the off gas discharge route to pass faster than purification target gas, an off gas tank, and a pressure boosting unit that raises the pressure of and supplies the off gas to the membrane separation unit. The off gas tank and the pressure boosting unit are upstream of the membrane separation unit. The device includes a recycle gas return route via which some recycle gas is returned to the source gas supply route. The operation control unit adjusts the off gas adjustment unit so the off gas discharge flow rate is a flow rate where the amount of off gas discharged from one adsorption tower during the desorption process is equivalent to the amount of off gas discharged from the off gas tank when the one adsorption tower starts the desorption process until another starts the desorption process.

A three-product PSA system which produces three product streams from a feed gas mixture comprising a light key component, at least one heavy key component, and at least one intermediate key component is described. The three-product PSA system produces a high pressure product stream enriched in the light key component, a low pressure tail gas stream enriched in the at least one heavy key component, and an intermediate pressure vent gas stream enriched in the at least one intermediate key component.

A method of obtaining helium from a helium-containing feed gas. Helium-containing feed gas is fed to a prepurifying unit that uses a pressure swing adsorption process to remove undesirable components from the helium-containing feed gas and obtain a prepurified feed gas. The prepurified feed gas is fed to a membrane unit connected downstream of the prepurifying unit and that has at least one membrane more readily permeable to helium than to at least one further component present in the prepurified feed gas. A pressurized low-helium retentate stream that has not passed through the membrane is fed to the prepurifying unit. The pressurized low-helium retentate is used to displace helium-rich gas from an adsorber that is to be regenerated into an already regenerated adsorber.

A portable pressure swing adsorption method and system for low flow rate gas processing. A method of processing of hydrocarbon gas includes feeding hydrocarbon gas through a first adsorption bed of a pressure swing adsorption system, recovering light product from the first adsorption bed during the feed time, obtaining heavy product from a second adsorption bed during the feed time, wherein the second adsorption bed depressurizes to about vacuum during the feed time, compressing the heavy product to obtain natural gas liquid and vapor, sending a volume of reflux gas through the first adsorption bed after the feed time to obtain additional light product, and adjusting the feed flowrate, the feed time, or the volume of reflux gas based on a gross heating value of the feed gas, wherein adjusting the volume of reflux gas includes combining NGL storage tank vapor with the reflux gas.

The present invention relates to a process cycle that allows for the stable production of mid-range purity oxygen from air, using traditional system designs. Typical cycles have a limited production benefit when generating O.sub.2 at lower than 90% purity, however they suffer a production loss at higher purity. The process cycles of the invention are capable of producing significantly more contained O.sub.2 at a lower purity. In addition to enhanced production capacity, lower power consumed per mass of product and more stable product purity and flow are realized by the process of the invention compared to traditional alternatives.