A process and facility for producing gaseous methane by purifying biogas from landfill, can include a VOC purification unit, at least one membrane, a booster, a CO.sub.2 purification unit, a cryodistillation unit comprising a heat exchanger, a distillation column, and a subcooler, a deoxo, and a dryer.

Disclosed are methods for removing acid gas from a feed stream of natural gas including acid gas, methane and ethane. The methods include alternating input of the feed stream between at least two beds of adsorbent particles comprising zeolite SSZ-13 such that the feed stream contacts one of the at least two beds at a given time in an adsorption step and a tail gas stream is simultaneously vented from another of the at least two beds in a desorption step. The contact occurs at a feed pressure of from about 50 to about 1000 psia for a sufficient period of time to preferentially adsorb acid gas from the feed stream. A product gas stream is produced containing no greater than about 2 mol % carbon dioxide and at least about 65 mol % of methane recovered from the feed stream and at least about 25 mol % of ethane recovered from the feed stream. The feed stream is input at a feed end of each bed. The product gas stream is removed from a product end of each bed. The tail gas stream is vented from the feed end of each bed. The methods require lower vacuum power consumption and allow improved hydrocarbon recoveries compared with known methods.

A process and facility for producing gaseous methane by purifying biogas from landfill can include a VOC purification unit, at least one membrane, a CO.sub.2 purification unit, a cryodistillation unit comprising a heat exchanger and a distillation column, a deoxo, and a dryer.

Systems and methods of separating components of a multi-component gas mixture are described herein. The systems include one or more packed bed columns packed with a biosorbent material. Upon passing the multi-component gas mixture through the packed bed column, substantially all of a polar component of the multi-component gas mixture is adsorbed by the biosorbent material and a non-polar component of the multi-component gas mixture is not substantially adsorbed by the biosorbent material.

Zero emission nested-loop (ZEN) reforming provides a scalable, eco-friendly process to produce high quality hydrogen at a relatively low operating cost. In one embodiment, a ZEN system comprises a reactor, a regenerator, and a photocatalytic reformer. During operation, the reactor receives a gas mixture and outputs hydrogen and catalyst adsorbed with carbon dioxide. The gas mixture is methane, steam, or hydrogen. Next, the regenerator receives the catalyst adsorbed with carbon dioxide and outputs carbon dioxide and desorbed catalyst. Next, the photocatalytic reformer receives carbon dioxide output by the regenerator and outputs methane and oxygen. The reactor receives at least some of the methane output by the photocatalytic reformer. By recycling methane in this way, the need for additional methane to fuel the system is reduced. The ZEN reforming system provides a novel technique to convert greenhouse gas emissions and carbon dioxide into oxygen and reusable methane gas.

A system for high-value utilization of organic solid waste includes an anaerobic digestion unit, a biogas measurement and collection unit and a methane purification and liquefaction unit. The anaerobic digestion unit includes an organic solid waste pretreatment system and an anaerobic digestion device. The biogas measurement and collection unit includes a gas flow meter and a high-pressure biogas collection device. The methane purification and liquefaction unit includes a high-pressure separation tank, a liquefaction pretreatment system, a heavy hydrocarbon and benzene removal device, a two-stage rectification system, a low-temperature pressure liquid storage tank device and a buffer storage tank. The organic solid waste undergoes an anaerobic digestion treatment to produce methane followed by collection, purification and liquefaction.

Treatment of hydrocarbon streams, and in one non-limiting embodiment refinery distillates, with reducing agents, such as borohydride and salts thereof, alone or together with at least one co-solvent results in reduction of the sulfur compounds such as disulfides, mercaptans, thiophenes, and thioethers that are present to give easily removed sulfides. In one non-limiting embodiment, the treatment converts the original sulfur compounds into hydrogen sulfide or low molecular weight mercaptans that can be extracted from the distillate with caustic solutions, hydrogen sulfide or mercaptan scavengers, solid absorbents such as clay or activated carbon or liquid absorbents such as amine-aldehyde condensates and/or aqueous aldehydes.

The present invention is directed to an intensified process cycle that utilizes the adsorption beds present to a substantially greater degree allowing the processing of significantly more gas and/or the generation of significantly more product. The elimination of purge steps, reduction in equalization step times, and introduction of overlapping feed and equalization steps which normally cause a degradation in performance for equilibrium-based cycles, frees extra step for other actions to be taken, such as additional equalization steps, etc.

The present invention generally relates to a process that utilizes tunable zeolite adsorbents in order to reduce the bed size for nitrogen removal from a methane (or a larger molecule) containing stream. The adsorbents are characterized by the rate of adsorption of nitrogen and methane and the result is a bed size that is up to an order of magnitude smaller with these characteristics (in which the rate selectivity is generally 30) than the corresponding bed size for the original tunable zeolite adsorbent that has a rate selectivity of >100x.

The present invention generally relates to a pressure swing adsorption process for separating an adsorbate impurity from a feed stream comprising product gas, said process comprising feeding the feed stream to an adsorbent bed at a pressure of from about 60 psig to 2000 psig, wherein said adsorbent bed comprises adsorbent having: An isosteric heat of adsorption of from about 5 kJ/mol to about 30 kJ/mol, as determined by the LRC method, for the adsorbate, and an equivalent 65 kJ/mol or less isosteric heat of adsorption for the product,
wherein the adsorbent has a rate of adsorption for the adsorbate impurity that is at least 10 times greater than the rate of adsorption for the product gas as determined by the TGA method and recovering said product gas with a reduced a level of said adsorbate impurity.

The invention also related to an adsorbent useful in PSA separations, particularly separating N.sub.2 from methane, CO.sub.2 from methane O.sub.2 from N.sub.2 and the like.