A system for separating olefinic hydrocarbon and hydrogen in an effluent fluid stream from a dehydrogenation reactor includes a heat exchanger that receives and partially condenses the effluent fluid stream so that a mixed phase effluent stream is formed. A primary separation device receives and separates the mixed phase effluent stream into a primary vapor stream and a primary liquid product stream. A heat exchanger receives and partially condenses the primary vapor stream so that a mixed phase primary stream is formed. A secondary separation device receives and separates the mixed phase primary stream into a secondary vapor stream and a secondary liquid product stream. A heat exchanger receives and warms the secondary vapor stream to provide refrigeration for partially condensing the effluent fluid stream and a heat exchanger receives and warms the secondary vapor stream to provide refrigeration for partially condensing the primary vapor stream. A mixed refrigerant compression system provides refrigerant to a heat exchanger to provide refrigeration.

A method and apparatus for producing liquefied natural gas. A pretreated natural gas stream is compressed in at least two serially arranged compressors to a pressure of at least 1,500 psia and cooled. The resultant cooled compressed natural gas stream is expanded in at least one work producing natural gas expander to a pressure less than 2,000 psia and no greater than the pressure to which natural gas stream has been compressed, thereby forming a chilled natural gas stream that is separated into a refrigerant stream and a non-refrigerant stream. The refrigerant stream is warmed in a heat exchanger through heat exchange with one or more process streams associated with pretreating the natural gas stream, thereby generating a warmed refrigerant stream. The warmed refrigerant stream and the non-refrigerant stream are then liquefied.

A method and system for producing liquid air wherein liquid refrigerant is cycled between two core tanks maintained at a temperature sufficient to liquify compressed air passed through condensing tubing in the interior of the core tanks. Liquid refrigerant is cycled by alternating high pressure gas from a high pressure tank to one of the core tanks, which forces liquid refrigerant from this tank through an expansion device to expand a portion of the liquid refrigerant to absorb heat in the other core tank, the resulting refrigerant gas being driven into a low pressure tank. A compression device transfers the refrigerant gas from the low pressure tank to the high pressure tank and maintains the pressure in the high pressure tank. Connections between the low and high pressure tanks and the core tanks are reversed with each cycle.

A nitrogen producing cryogenic air separation unit with an excess air circuit is provided. The nitrogen producing cryogenic air separation unit is capable of producing high pressure gaseous nitrogen without the use of a nitrogen product compressors and is also capable of producing high rates of liquid nitrogen without adding additional compression stages in the main air compressor and/or without a nitrogen recycle compressor.

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.

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.

Described herein are methods and systems for liquefying natural gas using an open-loop natural gas refrigeration cycle; coil wound heat exchanger units suitable for cooling one or more feed streams, such as for example one or more natural gas feed streams, via indirect heat exchange with a gaseous refrigerant; and methods and systems for removing heavy components from a natural gas prior to liquefying the natural gas using an open-loop natural gas refrigeration cycle.

Plant and method for liquefying a flow of gas, comprising a cooling circuit which is provided with an upstream end which is intended to be connected to a source of pressurised gas to be liquified and a downstream end which is intended to be connected to a user member, the plant comprising, between the upstream and downstream ends, a set of members which are intended to liquefy the gas and comprise at least one exchanger for cooling the gas, and at least one expansion turbine which is mounted on a rotary axle which is supported by at least one bearing of the gas-static type, the cooling circuit comprising a pressurised gas injection conduit having an upstream end which is intended to receive pressurised gas supplied by the source and a downstream end which is connected to the bearing in order to provide support to the rotary axle, the plant comprising a conduit for recovering the gas which has been used in the bearing, the conduit for recovering the gas comprising an upstream end which is connected to the bearing and a downstream end, characterised in that the downstream end of the conduit for recovering the as is connected to the cooling circuit between the upstream and downstream ends thereof in order to recycle at that location at least a portion of the gas which has been used to support the rotary axle of the bearing with a few to liquefying said gas.

A process for recovering at least one fluid (e.g. xenon gas and/or krypton gas, etc.) from a feed gas can include utilization of a compression system, primary heat exchanger unit, a pre-purification unit (PPU), and other units to separate and recover at least one desired fluid. In some embodiments, fluid flows output from a first heat exchanger or separation system of the plant can be split so that a portion of a stream is output for downstream processing to purify xenon (Xe) and/or krypton (Kr) product flow(s) while another portion of the stream is recycled to a compression system or the PPU to undergo further purification and heat exchange so that the product output for downstream processing has a higher concentration of Xe or Kr. Some embodiments can be configured to provide an improved recovery of Xe and/or Kr as well as an improvement in operational efficiency.

A method for efficiently reducing the energy required to convert natural gas from a natural gas pressure letdown facility at high pressure and pipeline/wellhead temperature to liquid natural gas in close proximity to/collocation with a natural gas pressure letdown/regulation facility using Non-Freezing Vortex Tubes (U.S. Pat. No. 5,749,231) in arrangement with indirect contact heat exchangers. The Non-Freezing Vortex Tubes separate the inlet natural gas into hot flow and cold flow outlet natural gas flows. One portion of the natural gas flow from the high-pressure transmission line/gas wellhead is directed through the Non-Freezing Vortex Tube and the cold outlet flow of the natural gas is directed to the indirect contact heat exchanger(s) to act as the cooling medium. The liquid natural gas plant's required natural gas flow is directed at the existing pipeline/wellhead gas pressure through the heat exchanger and cooled. The already cooled natural gas flow is directed to a turbo expander and refrigeration cold box system where it is further chilled and converted into liquid natural gas at −162° C.