Methods and systems are disclosed to compress raw, liquids-rich natural gas to high pressures while removing heavier hydrocarbons and water through inter-stage gas processing. Some variations provide a method for purifying and compressing natural gas, comprising: conveying a methane-containing input stream to first-compression stages; generating an initial compressed gas stream at a first pressure; conveying the initial compressed gas stream to a low-temperature separation sub-system configured to remove liquid contaminants, thereby generating an intermediate compressed gas stream at a second pressure; conveying the intermediate compressed gas stream to second-compression stages, to generate a compressed gas product stream at a third pressure; recovering purified and compressed natural gas; and feeding the compressed gas product stream into a mobile container. The sub-systems are preferably integrated into a single unit. The invention solves several problems associated with processing and transporting raw natural gas from initial production locations to end markets for final use.

A thermally integrated separation method, including exchanging heat indirectly between an inlet stream and a liquid carbon dioxide/NGL containing stream in a heat exchanger, thereby producing a cold inlet stream and a vaporized carbon dioxide/NGL containing stream, introducing the cold inlet stream into a cryogenic separation unit, thereby producing the liquid carbon dioxide/NGL containing stream and a methane-rich stream, introducing the methane-rich stream into a membrane separation unit, thereby producing a methane rich product stream, and a permeate stream, and introducing the vaporized carbon dioxide/NGL containing stream into a carbon dioxide/NGL separation unit, thereby producing a carbon dioxide rich product stream and a NGL rich product stream. Wherein, at least a portion of the liquid carbon dioxide/NGL containing stream bypasses the heat exchanger and is introduced into the carbon dioxide/NGL separation unit in liquid phase.

The invention relates to a method for extracting hydrocarbons from a subterranean formation, comprising: —providing a fluid, —injecting said fluid into the subterranean formation during a first period of time but not during a second period of time, and—collecting displaced hydrocarbons from the subterranean formation, wherein: at least part of the provision and/or injection of the fluid is carried out using solar energy.

A CO2 separation and liquefaction system such as might be used in a carbon capture and sequestration system for a fossil fuel burning power plant is disclosed. The CO2 separation and liquefaction system includes a first cooling stage to cool flue gas with liquid CO2, a compression stage coupled to the first cooling stage to compress the cooled flue gas, a second cooling stage coupled to the compression stage and the first cooling stage to cool the compressed flue gas with a CO2 melt and provide the liquid CO2 to the first cooling stage, and an expansion stage coupled to the second cooling stage to extract solid CO2 from the flue gas that melts in the second cooling stage to provide the liquid CO2.

Processes and apparatuses for recovering a high purity carbon dioxide stream. A first separation zone that may include a cryogenic fractionation column provides the high-purity CO.sub.2 stream. A vapor stream from the cryogenic fractionation column is passed to a second separation zone to separate the CO.sub.2 from the other components. The second separation zone may include a pressure swing adsorption unit or a solvent separation unit. The second separation zone provides a hydrogen enriched gas stream that may be used in a gas turbine. The second stream from the second separation zone includes carbon dioxide and, after a pressure increase in a compressor, may be recycled to the first separation zone.

A system and method for capturing and separating carbon dioxide from mixed gas streams. The gas stream is processed in a structure including a compression module comprising a plurality of compressors, intercoolers and inter-stage condensate separators. The flow path from the compression module includes a plurality of flow separators, gas stream splitters, heat exchangers and at least a first mixer and a first expander. The gas stream is sequentially compressed and cooled to form process condensate and separate it from the compressed gas stream. The gas stream is further dried and cooled to liquefy carbon dioxide and separate it from the non-condensable portion. Selective expansion of liquid carbon dioxide streams provides cooling for the system, and further energy efficiency is achieved by selective recycling of portions of gas streams, allowing for compact equipment and economical operation, while providing for high purity product streams of carbon dioxide.

Carbon dioxide is recovered from an exhaust gas in the form of liquid carbon dioxide or supercritical carbon dioxide utilizing a rotary separator. Nitrogen gas recovered from the rotary separator can be expanded to provide cooling for carbon dioxide in a closed-loop CO2 power cycle that is used to cool the exhaust gas upstream of the rotary separator. The recovery can power itself and can produce excess electricity from waste heat.

A pressurized CO.sub.2 rich gas is cooled down to condense at least part of the stream in a heat exchanger. A bulk of the CO.sub.2 is separated by partial condensation and distillation in order to obtain at least one non-condensable gas from a separation vessel. The non-condensable gas is optionally heated up to a temperature lower than −20° C. (membranes performances is greatly enhanced by low temperature operation). The non-condensable gas is introduced into a membrane permeation unit, producing a residue stream and a permeate stream (the permeate stream is enriched in CO.sub.2). The permeate stream is recycled to the process, optionally after compression. The method is auto-refrigerated, i. e. no external refrigerant is used to provide cooling below 0° C.

A compressing system includes a compression section that compresses a target gas to an intermediate pressure, which is equal to or higher than a critical pressure and lower than a target pressure to generate an intermediate supercritical fluid, a cooling section that cools the intermediate supercritical fluid generated in the compression section to near a critical temperature to generate an intermediate supercritical pressure liquid, and a pumping section that compresses the intermediate supercritical pressure liquid generated in the cooling section to a pressure that is equal to or higher than the target pressure. At least one of the intermediate supercritical pressure liquid compressed in the pumping section, a low-temperature liquid generated by extracting the intermediate supercritical pressure liquid on the upstream side of the pumping section to reduce pressure to near the critical pressure, and an external cooling medium is used as a cooling medium in the cooling section.

A system for conditioning a sour gas feed stream for a cryogenic distillation tower, comprising a dehydration unit configured to separate the sour gas feed stream into a first stream comprising water and a feed stream, and a sequential cooling assembly coupled to both the dehydration unit and the cryogenic distillation tower, wherein the sequential cooling assembly comprises a first stage configured to separate the feed stream into a partially cooled feed stream and a second stream comprising acid gas, a second stage configured to cool the partially cooled feed stream into a cooled feed stream and a third stream comprising acid gas, and a cooled feed stream header coupled to a cryogenic distillation tower feed inlet, wherein the first stage, the second stage, or both are configured to send at least one of the second and third streams to a bottom section of the cryogenic distillation tower.