A heavies removal heat exchanger cools at least a portion of a feed gas stream. A scrubbing section receives the cooled main feed gas stream. A stripping section receives a fluid stream from the scrubbing section. A stripping gas feed expansion device receives a portion of the feed gas stream and is in fluid communication with the stripping section. A side draw vapor line receives a vapor stream from the vapor outlet of the stripping section and is in fluid communication with a reflux stream cooling passage of the heavies removal heat exchanger. A reflux separation device receives fluid from the heavies removal heat exchanger and has a liquid outlet and a vapor outlet. The liquid outlet is in fluid communication with the scrubbing section. A return vapor expansion device receives a vapor stream from the scrubbing section and directs a cooled vapor stream to a return vapor stream warming passage of the heavies removal heat exchanger. The reflux separation device vapor outlet is configured so that fluid passing therethrough joins with fluid that has exited the return vapor expansion device either before or after the fluid that has exited the return vapor expansion device flows through the return vapor stream warming passage of the heavies removal heat exchanger.

Systems and methods are provided for increasing the efficiency of liquefied natural gas production and heavy hydrocarbon distillation. Air within an LNG production facility can be utilized as a heat source to provide heat to HHC liquid for distillation in a HHC distillation system. The mechanism of heat transfer from the air can be natural convection. Heat provided by natural gas, or compressed natural gas, can be also used for HHC distillation. Various other liquids can further be used to transfer heat to HHC liquid for distillation.

The invention relates to a system, method and apparatus for processing natural gas in an LNG facility. A natural gas feed is introduced into a heavies removal unit. The heavies removal system includes a heavies removal column and a distillation column. The heavies removal column and the distillation column are connected via a purge/recovery line. One or more components of the natural gas feed is purged from the heavies removal column to the distillation column via the purge/recovery line to obtain a specified concentration or concentration range of heavy components feeding into the distillation column.

A method for improved operation of a natural gas liquids stabilizer column, particularly a small-scale, is provided. The method can include the steps of: introducing a first feed stream comprising heavy hydrocarbons and natural gas to a stabilizer column to produce a top gas and a bottoms liquid, wherein the top gas has a higher concentration of natural gas as compared to the first feed stream, and the bottoms liquid has a higher concentration of heavy hydrocarbons as compared to the first feed stream; introducing a second feed stream into the stabilizer column, wherein the second feed stream has a higher concentration of natural gas as compared to the first feed stream, wherein the second feed stream is at a warmer temperature than the first feed stream when introduced into the stabilizer column, wherein the second feed stream is a gaseous stream; withdrawing the top gas from a top portion of the stabilizer column; withdrawing the bottoms liquid from a bottom portion of the stabilizer column; and sending at least a portion of the bottoms liquid to a liquid storage tank.

A method for an improved integration of refrigeration into conventional natural gas processing plants which use propane or similar hydrocarbon refrigerants either to supplement cooling by turbo-expanders or as the sole source of refrigeration.

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 process (100) for producing liquefied natural gas using a feedstock mixture that contains at least methane, one or more components boiling at a temperature lower than methane and one or more hydrocarbons boiling at a temperature higher than methane, wherein the hydrocarbon(s) boiling at a temperature higher than methane comprise one or more hydrocarbons freezing at a higher temperature, with a freezing point higher than −50° C. According to the invention the feedstock mixture is fed into a pressure swing adsorption process (10), in which a first fraction containing methane and a second fraction containing methane are formed, the first fraction containing methane contains, in addition to the methane, at least the predominant portion of the components of the feedstock mixture that boil more readily than methane and is low in or free from the hydrocarbons boiling less readily than methane, and the second fraction containing methane contains, in addition to the methane, at least the predominant portion of the hydrocarbons from the feedstock that boil less readily than methane and is low in or free from the components that boil more readily than methane, and the first fraction containing methane, or a portion thereof, is supplied for liquefaction (20). The invention also relates to a corresponding plant.

A process for liquefying a natural gas feed stream including cooling a feed gas stream to obtain a liquefied natural gas stream; introducing the liquefied natural gas stream into a deazotization column to produce a liquefied natural gas stream and a nitrogen-enriched vapor stream; at least partially condensing at least part of the nitrogen-enriched vapor stream to produce a two-phase stream; introducing the two-phase stream into a phase-separating vessel to produce a first liquid stream and a first nitrogen-enriched gas stream; introducing at least part of the nitrogen-enriched gas stream into a distillation column thereby producing a second nitrogen-enriched stream containing less than 1 mol % of methane and a second liquid stream containing less than 10 mol % of nitrogen; wherein at least part of the liquefied natural gas stream is used to cool the at least part of the nitrogen-enriched vapor stream in said heat exchanger.

A method and system for controlling the nitrogen concentration in an LNG product and fuel from flash gas within preferred ranges. A cooled LNG stream is separated into a nitrogen-enriched vapor stream, a fuel stream, and an LNG product stream using a plurality of phase separating devices, such as flash drum or rectifying column. A portion of the vapor stream is recycled to the rectifying column as reflux. A portion of a stream having a higher concentration of nitrogen is combined with the fuel stream to maintain the fuel stream within a desired nitrogen concentration range.