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.

Recovering helium from a gaseous stream includes contacting an acid gas removal membrane with a gaseous stream to yield a permeate stream and a residual stream, removing a majority of the acid gas from the residual stream to yield a first acid gas stream and a helium depleted clean gas stream, removing a majority of the acid gas from the permeate stream to yield a second acid gas stream and a helium rich stream, and removing helium from the helium rich stream to yield a helium product stream and a helium depleted stream. A helium removal system for removing helium from a gaseous stream including hydrocarbon gas, acid gas, and helium includes a first processing zone including a first acid gas removal unit, a second processing zone including a second acid gas removal unit, a third processing zone, and a helium purification unit.

A method for producing biomethane by purifying biogas from non-hazardous waste storage facilities involves compressing the initial gas flow, introducing the gas flow to be purified into at least one adsorber loaded with adsorbents capable of reversibly adsorbing the VOCs, and subjecting the VOC-depleted gas flow to at least one membrane separation step in order to partially separate the CO.sub.2 and O.sub.2 from the gas flow. The method also involves introducing the retentate from the membrane separation step into at least one adsorber loaded with adsorbents capable of reversibly adsorbing the major portion of the remaining CO.sub.2, subjecting the CO.sub.2-depleted gas flow exiting the adsorber loaded with adsorbents capable of reversibly adsorbing the major portion of the remaining CO.sub.2 to a cryogenic separation step in a distillation column in order to separate the O.sub.2 and N.sub.2 from the gas flow, and recovering the CH.sub.4-rich flow from the cryogenic separation step.

The present invention relates to the extraction of gasoline from a gas G, with (a) a step of extracting gasoline from the gas to be treated comprising methanol GM obtained from step (d), (b) a step of separating said fluid GL1 partially condensed in step (a), producing a first aqueous liquid phase Al , a first liquid phase H1 of hydrocarbon(s) a gaseous phase G1 obtained from the gas G; (c) a step of contacting a portion of the gas G to be treated with said first aqueous liquid phase A1, producing a second aqueous liquid phase A2, a gaseous phase of gas to be treated comprising methanol GM; (d) a step of mixing said gaseous phase of gas to be treated comprising methanol GM with the remainder of the gas G to be treated, producing a gas to be treated comprising methanol GM, (e) a step of stabilizing said first liquid phase H1 of hydrocarbon(s).

The present invention relates to a method and system for treating a flow back fluid exiting a well site following stimulation of a subterranean formation. More specifically, the invention relates to processing the flow back fluid, and separating into a carbon dioxide rich stream and a carbon dioxide depleted stream, and continuing the separation until the carbon dioxide concentration in the flow back stream until the carbon dioxide concentration in the flow back gas diminishes to a point selected in a range of about 50-80 mol % in carbon dioxide concentration, after which the lower concentration carbon dioxide flow back stream continues to be separated into a carbon dioxide rich stream which is routed to waste or flare, and a hydrocarbon rich stream is formed.

A method to recover and process hydrocarbons from a gas flare system to produce natural gas liquids (NGL), cold compressed natural gas (CCNG), compressed natural gas (CNG) and liquid natural gas (LNG). The method process provides the energy required to recover and process the hydrocarbon gas stream through compression and expansion of the various streams.

A method to recover hydrocarbonfractions from refineries gas streams involves a pre-cooled heat refinery fuel gas stream mixed with a pre-cooled and expanded supply of natural gas stream in an inline mixer to condense and recover at least C.sub.3.sup.+ fractions upstream of a fractionator. The temperature of the gas stream entering the fractionator may be monitored downstream of the in-line mixer. The pre-cooled stream of high pressure natural gas is sufficiently cooled by flowing through a gas expander that, when mixed with the pre-cooled refinery fuel gas, the resulting temperature causes condensation of heavier hydrocarbon fractions before entering the fractionator. A further cooled, pressure expanded natural gas reflux stream is temperature controlled to maintain fractionator overhead temperature. The fractionator bottoms temperature may be controlled by a circulating reboiler stream.

Systems and processes are provided to prevent light ends such as methane, ethylene and ethane from building up in an olefin/paraffin separation system that uses a combination of a membrane and distillation column for this separation. In one embodiment a small stripper column is provided downstream from a selective hydrogenation reactor. In the other embodiment, a surge vessel with a receiver is added to the retentate stream of the membrane unit.

The invention relates to a process for the combined production of hydrogen and carbon dioxide from a hydrocarbon mixture, in which the residual gas of a PSA H.sub.2 (12) is separated by permeation in order to reduce the hydrocarbon content thereof and the hydrocarbon-purified gas is separated at a low temperature to produce a carbon dioxide-rich liquid (22).

A method of separating hydrocarbons containing three or more carbon atoms from an off-gas stream is provided. This method includes separating a light ends stream from a fractionator, thereby producing a stream rich in hydrocarbons containing three or more carbon atoms, and a stream lean in hydrocarbons containing three or more carbon atoms, separating the stream lean in hydrocarbons containing three or more carbon atoms in a membrane unit, thereby producing a permeate stream enriched in hydrocarbons containing three or more carbon atoms and a retentate stream, and separating the stream rich in hydrocarbons containing three or more carbon atoms in one or more separation columns, thereby producing one or more streams selected from the group consisting of a propylene stream, a propane stream, a butane stream, a light cat naptha stream, and a heavy cat naptha stream.