A process for obtaining a product gas and product LNG having pressure P1 close to the atmospheric pressure from lean LNG, includes: a) branching the lean LNG to obtain a first flow and a second flow; b) cooling the second flow by using a refrigerant; c) branching a liquid flow derived from the cooled second flow to obtain refrigerant LNG and remaining LNG; d) subjecting the remaining LNG to pressure reduction and gas-liquid separation to obtain a gas phase flow and a liquid phase flow (product LNG) having pressure P1; e) subjecting the refrigerant LNG to pressure reduction; f) using a flow from the step e as the refrigerant; g) joining, before or after the step f, the gas phase flow having pressure P1 to a flow from the step e; h) liquefying a flow resulting from the steps f and g by pressure increase and cooling (through heat exchange with the first flow); i) increasing the first flow in pressure before the step h; j) obtaining the product gas by regasifying the first flow after the steps h and i; and k) joining a flow liquefied in the step h to the second flow.

A method for recovering C2 components in a methane-containing industrial gas includes the steps of (1) cooling a compressed methane-containing industrial gas and performing gas-liquid separation; (2) absorbing C2 components in the gas phase by using an absorbent to obtain an absorption rich liquid; (3) returning the absorption rich liquid to the compression in step (1) or mixing the absorption rich liquid with the liquid phase obtained in step (1) to obtain a mixed liquid, and depressurizing the mixed liquid or the absorption rich liquid; (4) performing methane desorption on the depressurized stream to obtain a rich absorbent, or performing second gas-liquid separation on the depressurized stream, followed by methane desorption on the second liquid phase to obtain a rich absorbent; and (5) desorbing and separating the rich absorbent to obtain a lean absorbent and an enriched gas, and recycling and reusing the lean absorbent.

A method to recover olefins and C.sub.2.sup.+ fractions from refineries gas streams. The traditional recovery methods employed at refineries are absorption with solvents and cryogenic technology using compression and expansion aided by external refrigeration systems. In contrast to known methods, there is provided first a pre-cooling heat exchanger on a feed line feeding the gas stream to a in-line mixer, secondly by injecting and mixing a stream of LNG to condense the C.sub.2.sup.+ fractions upstream of the fractionator. The temperature of the gas stream entering the fractionator is monitored downstream of the in-line mixer. A LNG stream is temperature controlled to flow through the injection inlet and mix with the feed gas at a temperature which results in the condensation of the C.sub.2.sup.+ fractions before entering the fractionator. A LNG reflux stream is temperature controlled to maintain fractionator overhead temperature. The fractionator bottoms temperature is controlled by a circulating reboiler stream.

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.

The invention relates to mixtures comprising molecular hydrogen, hydrocarbons, and nitrogen oxides; to processes for removing at least a portion of the nitrogen oxides therefrom; to equipment useful in such processes; and to the use of such hydrocarbons for, e.g., chemical manufacturing.

An expander and motor-compressor unit is disclosed. The unit includes a casing and an electric motor arranged in the casing. A compressor is arranged in the casing and drivingly coupled to the electric motor through a central shaft. Furthermore, a turbo-expander is arranged for rotation in the casing and is drivingly coupled to the electric motor and to the compressor through the central shaft.

A process is described herein for removing high freeze point hydrocarbons, including benzene compounds, from a mixed feed gas stream. The process involves cooling process streams in one or more heat exchangers and separating condensed compounds in multiple separators to form a methane-rich product gas stream. Select solvent streams from a fractionation train and/or separate solvent streams are employed to lower the freeze point of one or more streams that contain high freeze point hydrocarbons. A corresponding system also is disclosed.

The claimed invention provides a method and an apparatus for separating hydrocarbons, wherein the method and the apparatus are used for separating a hydrocarbon having 3 or more carbon atoms including at least propane (hereinafter sometimes called “C3+ NGL”. NGL: Natural Gas Liquid) from liquefied natural gas (LNG).

A process for purifying a feed gas including methane and heavy hydrocarbons, including: step a): cooling the feed gas in a heat exchanger; step b): introducing the resulting into a first phase separator to produce a liquid stream depleted in methane and enriched in heavy hydrocarbons and a gas stream; step c): separating the gas stream in a membrane from which a methane-enriched permeate stream and a partially condensed residue stream exit; step d): introducing the residue stream from step c) into a second phase separator vessel in order to produce a liquid stream and a gas stream; step e): introducing at least one portion of the gas stream resulting from step d) into a JT expansion means; and step f): heating at least one portion of the expanded stream in the heat exchanger used in step a) counter-current to the feed stream in order to cool the latter.

A system for sustainable generation of energy, comprising at least one device for converting natural power into useful energy, and at least one internal combustion engine or heat engine. The internal combustion engine or heat engine may be connected to a gas cleaning device for fuel or heat supply. A method for sustainable generation of energy, comprising the steps of generating a first amount of useful energy by converting natural power; and generating a second amount of energy by operating at least one internal combustion engine or heat engine, wherein the internal combustion engine or heat engine is driven by fuel or heat derived from cleaning a waste gas.