Methods and systems for removing water vapor from a feed gas prior to further processing the feed gas according to a downstream PSA process are described. The feed gas can include CO.sub.2 and/or CO and/or H.sub.2 and the PSA process can be used to separate components of the feed gas from one another, for instance, for CO.sub.2 capture. Light product off of the PSA process is utilized to regenerate desiccant of a dryer used in the water vapor removal process that is carried out prior to the feed gas entering the PSA process. The water vapor removal process can be heated by providing thermal energy directly to the dryer and/or to a regenerating stream that regenerates the desiccant of the dryer. The thermal energy can be low cost energyfor instance, waste heat off of a system that provides the feed gas.

A process of treating a natural gas stream is provided comprising sending natural gas stream through a first adsorbent bed to remove water and heavy hydrocarbons (C8+) to produce a partially treated gas stream in which the first adsorbent bed is regenerated by a temperature swing adsorption process and then sending the partially treated gas stream through a second adsorption bed to remove carbon dioxide and lighter hydrocarbons (C7) to produce a purified natural gas stream wherein said second adsorption bed is regenerated by a temperature pressure swing adsorption process.

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.

The invention relates to a process for the regeneration of an adsorber. For the regeneration a liquid stream (S2) comprising at least one alkane is converted from liquid phase into gaseous phase. Then the adsorber is regenerated and heated by contact with gaseous stream (S2) up to 230 to 270 C. Subsequently, the adsorber is cooled first by contact with gaseous stream (S2) to a temperature of 90 to 150 C. followed by cooling with liquid stream (S2) to a temperature below 80 C. The outflow of the adsorber (S2*) during the cooling with gaseous stream (S2) and optionally the outflow of the adsorber (S2*) during cooling with liquid stream (S2) is recycled in at least one of these steps.

Pressure shift adsorption (PSA) process for producing a gas stream enriched with compound X from a feed gas stream, using N adsorbers with N5, each adsorber being subjected to a pressure cycle having a phase time corresponding to the duration of the pressure cycle divided by the number of adsorbers, and a series of active steps, characterized in that each adsorber n follows the pressure cycle with an offset of one phase time with respect to the pressure cycle of the adsorber n1 with nN, and during each phase time, only one active step or a part of active step takes place.

The invention relates to a method for regulating a unit for separating a gas stream, having P adsorbers, where P2, each following a PSA-type adsorption cycle with a phase time shift, the method involving the steps of operating the unit according to the nominal cycle when the required flow rate is equal to a nominal flow rate or optionally when the required flow rate is higher than the nominal flow rate, and operating the unit according to the reduced cycle when the required flow rate is lower than or equal to a predetermined flow rate, the predetermined flow rate being lower than the nominal flow rate.