A liquefaction system is capable of sequentially or simultaneously liquefying multiple feed streams of hydrocarbons having different normal bubble points with minimal flash. The liquefying heat exchanger has separate circuits for handling multiple feed streams. The feed stream with the lowest normal boiling point is sub-cooled sufficiently to suppress most of the flash. Feed streams with relatively high normal boiling points are cooled to substantially the same temperature, then blended with bypass streams to maintain each product near its normal bubble point. The system can also liquefy one stream at a time by using a dedicated circuit or by allocating the same feed to multiple circuits.

Process for producing biomethane from a biogas stream including methane, carbon dioxide and at least one impurity chosen from ammonia, volatile organic compounds, water, sulfur-based impurities (H.sub.2S) and siloxanes. A biogas stream is dried, the at least one impurity is at least partially removed by solidification and removal of the impurity. The methane and the carbon dioxide contained in the biogas obtained from the second step are separated so as to produce a biomethane stream and a CO.sub.2 stream.

The present invention relates to a method of cooling and separating a hydrocarbon stream: (a) passing an hydrocarbon feed stream (7) through a first cooling and separation stage to provide a methane enriched vapour overhead stream (110) and a methane depleted liquid stream (10); (b) passing the methane depleted liquid stream (10) to a fractionation column (200) to obtain a bottom condensate stream (210), a top stream enriched in C1-C2 (220) and a midstream enriched in C3-C4 (230), (c) cooling the upper part of the fractionation column (201) by a condenser (206), (d) obtaining a split stream (112) from the methane enriched vapour overhead stream (110) and obtaining a cooled split stream (112) by expansion-cooling the split stream (112), (e) providing cooling duty to the top of the fractionation column (201) using the cooled split stream (112).

A thermoacoustic refrigerator includes at least one pair of pulse combustion tubes (10), preferably Rijke tubes, each tube (10) having a pair of spaced-apart Stirling engines (12), coupled together but with no separating membrane therebetween.

A system includes a waste heat recovery heat exchanger configured to heat a heating fluid stream by exchange with a heat source in a crude oil associated gas processing plant. The system includes a modified Goswami cycle energy conversion system including a first group of heat exchangers configured to heat a first portion of a working fluid by exchange with the heated heating fluid stream and a second group of heat exchangers configured to heat a second portion of the working fluid. The modified Goswami cycle energy conversion system includes a separator configured to receive the heated first and second portions of the working fluid and to output a vapor stream of the working fluid and a liquid stream of the working fluid; a first turbine and a generator are configured to generate power by expansion of a first portion of the vapor stream of the working fluid; a cooling subsystem including one or more cooling elements configured to cool a chilling fluid stream by exchange with a cooled second portion of the vapor stream of the working fluid; and a second turbine configured to generate power from the liquid stream of the working fluid.

A method for cryogenic cooling without fouling is disclosed. The method comprises providing a first cryogenic liquid saturated with a dissolved gas; expanding the first cryogenic liquid into a separation vessel, separating into a vapor, a second cryogenic liquid, and a first solid; drawing the vapor into a heat exchanger and the second cryogenic liquid and the first solid out of the separation vessel; cooling the vapor against a coolant through the heat exchanger, causing the vapor to form a third cryogenic liquid and a second solid, the second solid dissolving in the third cryogenic liquid; and combining the second cryogenic liquid and the first solid with the third cryogenic liquid, producing a final cooled slurry. In this manner, the cryogenic cooling is accomplished without fouling.

A method for the separation of liquid CO.sub.2 from a 2 phase feed stream, the process comprising the steps of: cooling the feed stream to a cryogenic temperature; expanding the cooled stream so as to further lower the temperature of the feed through expansion; mechanically separating the expanded stream, using a mechanical separator, into a gas phase and a liquid CO.sub.2 phase, and; venting the gas phase and outflowing the liquid CO.sub.2.

The present invention provides strategies to integrate adsorption and liquefaction techniques to separate hydrocarbon feed mixtures into purified light and heavy components, respectively. Initially, the hydrocarbon stream is separated into a light and heavy stream. The light stream can be integrated into a natural gas product. The heavy stream is partially liquefied. A first gas liquid separation of the partially liquefied heavy stream at an elevated pressure separates the liquid heavy stream from a methane-containing gas. The rejected methane component, which generally will include some rejected C2 and C3+ material, can be recycled to be combined with the feed mixture for re-processing. A further aspect of the strategy is then to practice at least one additional gas-liquid separation of the separated liquid heavy stream at a lower pressure effective to help further resolve the liquid heavy stream from C2-containing gas. The rejected C2 component, which generally will include some rejected C1 and C3+ material, can then be recycled back into the feed mixture for reprocessing or used as all or a portion of a light hydrocarbon product.

A process for removing CO.sub.2 from a methane-containing gas, having the steps of providing a methane-containing gas containing at least CO.sub.2 as an impurity, cooling the gas to remove CO.sub.2 from the methane-containing gas by freezing out same, and additionally reducing the CO.sub.2 concentration of the gas using a pressure temperature swing adsorption apparatus (PTSA), whereby a methane-enriched product gas is obtained. At least a part of the product gas is then used as treatment gas and is passed through the PTSA for treatment of the PTSA, whereby CO.sub.2 is absorbed by the treatment gas and is removed from the PTSA as a CO.sub.2-enriched treatment gas. The treatment gas is then recycled and admixed with the methane containing gas.

A system includes a waste heat recovery heat exchanger configured to heat a heating fluid stream by exchange with a heat source in a crude oil associated gas processing plant; and an Organic Rankine cycle energy conversion system. The Organic Rankine cycle energy conversion system includes a heat exchanger configured to heat a first portion of a working fluid by exchange with the heated heating fluid stream; and a cooling subsystem including one or more cooling elements each configured to cool one or more of a process stream from the crude oil associated gas processing plant and a cooling water stream for ambient air cooling by exchange with a second portion of the working fluid. The Organic Rankine cycle energy conversion system includes an ejector configured to receive the second portion of the working fluid from the cooling subsystem and a third portion of the working fluid; a turbine and a generator configured to generate power by expansion of a fourth portion of the working fluid; and a cooling element configured to cool a stream of working fluid including an output stream of working fluid from the ejector and the expanded fourth portion of the working fluid from the turbine and generator.