A natural gas liquefaction process suited for offshore liquefaction of natural gas produced in association with oil production is described.

A process and apparatus for liquefying a gas stream comprising hydrocarbons and sour species is provided in which the sour species are removed in liquefied form as the sweetened gas stream is progressively cooled to liquefaction temperatures. The process involves cooling the gas stream in a manner to produce a cooled gas stream comprising gaseous hydrocarbons and residual sour species. The cooled gas stream is then treated with a cold solvent to deplete the cooled gas stream of residual sour species. The resulting cooled sweetened gas stream is then further cooled to produce liquid hydrocarbons.

A method and apparatus of removing heavy hydrocarbons from a natural gas feed stream, the method comprising using first and second hydrocarbon removal systems in series such that the first system processes the natural gas feed stream to produce a heavy hydrocarbon depleted natural gas stream and the second system processes at least a portion of the heavy hydrocarbon depleted natural gas stream from the first system to produce a natural gas stream lean in heavy hydrocarbons, wherein one of said systems is a adsorption system that comprises one or more beds of adsorbent for adsorbing and thereby removing heavy hydrocarbons from a heavy hydrocarbon containing natural gas, and the other of said systems is a gas-liquid separation system for separating a heavy hydrocarbon containing natural gas into a heavy hydrocarbon depleted natural gas vapor and a heavy hydrocarbon enriched liquid.

A method for treating a gas stream comprising hydrogen and propane, where a combination of membrane separation and elevated pressure distillation is used to separate the hydrogen gas from the propane gas.

A method of gas production from a field containing natural gas processing particularly for transport of stranded gas to conserve resources and reduce emissions includes extracting gas a gas supply from a plurality of individual gas wells in the field and initially at the individual gas wells providing a recovery unit having a production capacity matching that of the well for carrying out liquid recovery from the gas supply and compression of the natural gas. When a production rate of the well declines to a low level, typically to about 20% of the original, the recovery unit is removed for redeployment either at a central plant or at other wells which are still at the high production and is substituted by a dehydration system and gas compressor arranged to fill portable pressure vessels typically on trucks for transporting the compressed natural gas to a main pipe line.

A process for recovering liquid hydrocarbons from a gaseous stream containing the liquid hydrocarbons, the process comprising (a) providing a dehydrated gaseous stream including carbon dioxide, methane, ethane, propane, and C4 and heavier hydrocarbons; (b) cooling the dehydrated gaseous stream to form a condensate stream including C4 and heavier hydrocarbons; (c) separating at least a portion of the carbon dioxide, methane and ethane from the condensate stream; and (d) distilling the condensate stream to thereby form a liquid hydrocarbon stream.

Low grade waste heat is captured in a gas-oil separation plant (GOSP). Heat is transferred from a first hydrocarbon gas stream to a first portion of a mixed refrigerant stream to vaporize the first portion. Heat is transferred from a first portion of a mixture of the first hydrocarbon gas stream and a second hydrocarbon gas stream to a second portion of the mixed refrigerant stream to vaporize the second portion. Heat is transferred from a second portion of the mixture to a third portion of the mixed refrigerant stream to vaporize the third portion. A combined stream, including the vaporized first, second, and third portions, is flowed through a turbine-generator. Flowing the combined stream through the turbine-generator causes a rotor of the turbine-generator to rotate. Electrical power is generated in response to rotation of the rotor. The combined stream is condensed to reform the mixed refrigerant stream.

Contemplated plants for flexible ethane recovery and rejection by allowing to switch the top reflux to the demethanizer from residue gas to the deethanizer overhead product and by controlling the flow ratio of feed gas to two different feed gas exchangers. Moreover, the pressure of the demethanizer is adjusted relative to the deethanizer pressure for control of the ethane recovery and rejection.

Contemplated plants for flexible ethane recovery and rejection by allowing to switch the top reflux to the demethanizer from residue gas to the deethanizer overhead product and by controlling the flow ratio of feed gas to two different feed gas exchangers. Moreover, the pressure of the demethanizer is adjusted relative to the deethanizer pressure for control of the ethane recovery and rejection.

A process for recovery of natural gas liquids is disclosed, the process including: fractionating a gas stream comprising nitrogen, methane, ethane, and propane and other C.sub.3+ hydrocarbons into at least two fractions including a light fraction comprising nitrogen, methane, ethane, and propane, and a heavy fraction comprising propane and other C.sub.3+ hydrocarbons; separating the light fraction into at least two fractions including a nitrogen-enriched fraction and a nitrogen-depleted fraction in a first separator; separating the nitrogen-depleted fraction into a propane-enriched fraction and a propane-depleted fraction in a second separator; feeding at least a portion of the propane-enriched fraction to the fractionating as a reflux; recycling at least a portion of the propane-depleted fraction to the first separator. In some embodiments, the nitrogen-enriched fraction may be separated in a nitrogen removal unit to produce a nitrogen-depleted natural gas stream and a nitrogen-enriched natural gas stream.