A process for producing a liquified natural gas stream that includes cooling at least a portion of a pressurized natural gas feed stream by heat exchange contact with first and second expanded refrigerants that are used in independent refrigeration cycles. The first expanded refrigerant is selected from methane, ethane and treated and pressurized natural gas. The second expanded refrigerant is nitrogen.

Lng production using dual independent expander refrigeration cycles

The present invention is a process for phase separating, dephlegmating and optionally distilling a feed gas stream to recover a light gas product and a heavy hydrocarbon product wherein a predominant amount of the refrigeration for the process is provided by a two temperature and two pressure stage multicomponent closed-circuit refrigeration cycle.

Staged multicomponent refrigerant cycle for a process for recovery of C3+ hydrocarbons

Unreacted monomer present in an ethylene/C 3 -C 8 alpha-olefin copolymer product produced in a catalyzed fluid bed polymerization process is purged with a gaseous stream obtained by subjecting a portion of the gaseous effluent from the fluidized bed to a partial condensation, separating the liquid phase from the gaseous phase obtained and employing the gaseous phase as the gas to purge unreacted monomer from the copolymer product.

Monomer recovery in gas phase fluid bed olefin polymerization

A low temperature phase separation, dephlegmation and distillation process is described for resolving a light hydrocarbon gas stream to recover and purify C3+ and/or C4+ hydrocarbons. The phase separation bottoms stream is segregated from the dephlegmation bottoms stream and both streams are expanded to produce refrigeration for the feed stream. Both streams are then separately introduced into a distillation column for final purification of the heavy hydrocarbon product.

Process for recovery and purification of c3-c4+ hydrocarbons using segregated phase separation and dephlegmation

The invention relates to a method for the cryogenic separation, the cooling or the liquefaction of a fluid using an exchange line, that comprises extracting from said exchange line at least one dual phase fluid (11), separating said dual phase fluid into at least one vapour fraction (4) and one liquid fraction (5) in a phase separator (40), expanding at least one portion of the liquid fraction (5) using a first expansion means (60, 90), reinjecting, reheating and at least partially vaporising said expanded liquid fraction in the exchange line, the first expansion means being a valve, wherein during the cooling of said exchange line, at least a fraction of the fluid extracted from the exchange line (2, 4 or 5) and/or from the phase separator (40) is expanded in second expansion means (61, 71, 81, 91) parallel to the first expansion means (6), while during a normal operation, the second expansion means is essentially closed.

Method For Cooling A Cryogenic Exchange Line

In a process for the separation of a gas mixture at superatmospheric pressure by partial condensation at cryogenic temperatures and wherein the separated condensate and uncondensed vapor are passed back as returning streams in indirect countercurrent heat exchange relationship with the incoming feed mixture, the power required for providing the refrigeration and energy requirements for the separation are reduced by supplying said requirements by means of a heat pump alone or together with at least one separate refrigeration cycle and/or some Joule-Thomson expansion of the condensate, and in the heat pump a compressed multi-component gaseous medium is condensed by heat exchange with said returning streams over a first temperature range and then expanded by Joule-Thomson expansion, and the expanded condensate is evaporated by heat exchange with the feed gas mixture over a lower temperature range than said first temperature range, and recycled for recompression.

Melvyn Duckett

Papers

Separation of gas mixtures by partial condensation