Disclosed in certain embodiments are methods of removing water from a gas feed stream comprising mercaptans and water during an adsorption step of an adsorption cycle.

An apparatus that includes (A) an atmospheric water extraction unit; and (B) a direct air capture unit positioned downstream of and in communication with the atmospheric water extraction unit, wherein the apparatus is capable of reversibly operating in (i) adsorption mode to adsorb water and CO.sub.2 from an incoming air stream and (ii) regeneration mode to release adsorbed water and CO.sub.2, wherein the atmospheric water extraction unit comprises a first desiccant bed comprising a sorbent that adsorbs water from an incoming air stream during adsorption mode and releases water during regeneration mode, and wherein the direct air capture unit comprises a first moisture-responsive CO.sub.2 sorbent bed comprising a sorbent that adsorbs CO.sub.2 from an air stream during adsorption mode and releases CO.sub.2 upon contact with water vapor during regeneration mode.

A multi-stage process to remove contaminant gases from raw methane streams is provided. The present technology is an innovative solution to recover and purify biogas by use of a process having at least two pressure swing adsorption stages. Taking advantage of the presence of carbon dioxide in the raw biogas streams, nitrogen and oxygen are bulky removed in the first stage, using selective adsorbents, and a nitrogen and oxygen-depleted intermediate stream is yielded to the second stage. The second stage employs an adsorbent or adsorbents to selectively remove carbon dioxide and trace amounts of remaining nitrogen and oxygen, thus producing a purer methane stream that meets pipeline and natural gas specifications.

A method of purifying gaseous mixtures, for example ternary or quaternary gaseous mixtures, using a sorbent media comprising two or more sorbent materials. The method involves obtaining a target gas from a gaseous composition comprising the target gas, a first gas and a second gas, and optionally further gases by contacting the gaseous composition with the sorbent media to remove at least some of the first gas and at least some of the second gas from the gaseous composition. The sorbent media comprises at least a first sorbent material and a second sorbent material; wherein the first sorbent material has a higher adsorption selectivity for the first gas than for the target gas; and wherein the second sorbent material has a higher adsorption selectivity for the second gas than for target gas. The method may be particularly useful for the separation of pure ethylene, methane or propylene from such gaseous mixtures. A sorbent media and an apparatus for obtaining a target gas from such a gaseous composition are also disclosed.

A system and method for sulfur recovery, including hydrogenating Claus tail gas, quenching the hydrogenated gas, adsorbing water and hydrogen sulfide from the quenched gas, and regenerating adsorbent with carbon dioxide and/or nitrogen and heating the adsorbent in a regeneration temperature ramp to desorb primarily hydrogen sulfide in a first part of the temperature ramp.

A pressure swing adsorption apparatus for the removal of one or more components such as oxygen from a mixture of gases such as air is disclosed. The apparatus includes pairs of columns (14, 16) for receiving a stream of compressed air with one column operating in a working mode whilst the other said column operates in a purging mode. The columns contain carbon molecular sieve material (26) for adsorbing oxygen and a desiccant material formed into a plurality of tubes (28).

A process for treating a petroleum fraction and for efficiently absorbing an organic halogen compound from a fluid mixture of the organic halogen compound and an inorganic halogen compound derived from crude oil. Also disclosed is an improvement in absorption performance of a halogen-compound-absorbing material, thereby reducing the frequency with which the absorbing material is exchanged. The absorbing agent includes attapulgite (palygorskite) having high absorption performance with respect to organic halogen compounds. Also disclosed is an absorption column in which the aforementioned absorbing agent and a halogen-compound-absorbing agent, that includes zinc oxide, are disposed in series, thereby making it possible to raise the treatment performance with respect to a fluid that contains, in high concentrations, the organic halogen compound in addition to the inorganic halogen compound.

A system and method of pre-purification of a feed gas stream is provided that is particularly suitable for pre-purification of a feed air stream in cryogenic air separation unit. The disclosed pre-purification systems and methods are configured to remove substantially all of the hydrogen, carbon monoxide, water, and carbon dioxide impurities from a feed air stream and is particularly suitable for use in a high purity or ultra-high purity nitrogen plant. The pre-purification systems and methods preferably employ two or more separate layers of hopcalite catalyst with the successive layers of the hopcalite separated by a zeolite adsorbent layer that removes water and carbon dioxide produced in the hopcalite layers. Alternatively, the pre-purification systems and methods employ a hopcalite catalyst layer and a noble metal catalyst layer separated by a zeolite adsorbent layer that removes water and carbon dioxide produced in the hopcalite layer.

The present invention relates to systems and methods for conrolling the atmosphere in the cabin (1) of a vehicle. The system comprises a carbon dioxide removal conduit (2) comprising a regenerable carbon dioxide removal chamber (5,6) containing a carbon dioxide sorbent material and a regeneration circuit (7) arranged to expel the desorbed carbon diocide at a location exterior (8) of the cabin (1) The system is operable to maintain a carbon dioxide level below 1000 ppm in the passenger cabin for a period of at least 5 minutes while restricting the flow of air from outside the vehicle into the passenger cabin to 10 L/s or less.

A (V)PSA unit for purifying a gas stream by adsorption is provided. The (V)PSA unit comprises, arranged successively in the direction of flow of the feed gas stream, a rotary-structured adsorbent wheel configured so as to drive the gas stream therethrough in an axial manner and allowing the feed gas to dry to a level corresponding to a dew point below −30 C, and an adsorber with a centripetal radial configuration, comprising a bed of particulate adsorbent.