In a method for separating air by cryogenic distillation using a column system consisting of a higher pressure column operating at a first pressure and a lower pressure column operating at a second pressure, a first air flow constituting between 75% and 98% of the air sent to the column system compressed to a third pressure above the first pressure, is sent to the higher pressure column, a second air flow constituting between 5% and 25% of the air sent to the column system is compressed to a fourth pressure above the second pressure but lower than the third pressure, is sent to the lower pressure column, a third column separates an argon-enriched flow and the air sent to the lower pressure column constitutes between 10% and 25% of the total air sent to the column system.

The method includes cooling and liquefying a feed gas stream, separating a stream obtained from the feed gas stream, and recovering a treated gas stream and a natural gas liquid stream. The method further includes compressing the treated gas stream in order to form a compressed treated gas stream, and fractionating the natural gas liquid stream into a plurality of hydrocarbon fractions (28, 30, 32, 33). The method additionally includes withdrawing from the compressed treated gas stream, of a recycle stream, and reintroducing the recycle stream without cooling into the feed gas stream, into the cooled feed gas stream, or into a stream obtained from the cooled feed gas stream upstream of an expander.

An LNG plant comprises a cold box and a refrigeration unit fluidly coupled with a plurality of heat exchanger passes in the cold box. The refrigeration unit is configured to provide a first refrigerant stream to a first heat exchanger pass of the plurality of heat exchanger passes at a first pressure, a second refrigerant stream to a second heat exchanger pass at a second pressure, and a third refrigerant stream to a third heat exchanger pass at a third pressure. The second refrigerant stream comprises a first portion of the first refrigerant stream, and the third refrigerant stream comprises a second portion of the first refrigerant stream. The second pressure and the third pressure are both below the first pressure. The cold box is configured to produce LNG from a natural gas feed stream to the cold box using a refrigeration content from the refrigeration unit.

Techniques and systems for separating components of a mixture of compressed gases each having different boiling points are described. One example system includes multiple recovery stages that each recover one of the gases by condensing it into liquid form. The recovery stages are chained together, such that each stage recovers a gas having a boiling point that is higher than those of the gases to be recovered in downstream stages. Each stage typically includes a warming element that is fluidly coupled to a condenser element that provides a surface cooled to a temperature low enough to condense one of the gases, but high enough such that the remaining gases remain in gaseous form. The system may include an initial evaporator stage that heats a liquid solution of phytochemical extracts and multiple solvents, thereby recovering the extracts and producing the mixture of gaseous solvents.

Gas processing methodology for high efficiency recovery of propane and/or ethane from a natural gas feed stream. The method is conducted without turboexpansion, and in some embodiments, without the use of a refrigeration system. A natural gas stream is processed to have gas and liquid portions. The gas portions are cooled and flow to a refluxed absorber column and the liquid portions flow to a lower pressure distillation column. Bottoms of the absorber column are depressurized into a separator, with the separator overhead vapor being used as a source of absorber column reflux. The separator liquids are fed into the lower pressure distillation column and the distillation column overhead vapor stream is used to cool the feed and/or reflux streams. The overhead vapour stream from the lower pressure distillation can be recycled to the absorber, either as a recycle or a source of reflux.

A hydrogen feed stream is introduced into a primary refrigeration system of a precooling system and cooling the hydrogen stream to a first precooling temperature. From there, the precooled hydrogen stream is then introduced to a secondary refrigeration system of the precooling system and cooling the precooled hydrogen stream to a second temperature. Next, the cooled hydrogen stream is then liquefied in the liquefaction system to produce liquid hydrogen.

An integrated industrial unit is provided, which can include: a nitrogen source configured to provide liquid nitrogen; a hydrogen source; a hydrogen liquefaction unit, wherein the hydrogen liquefaction unit comprises a precooling system, and a liquefaction system; and a liquid hydrogen storage tank, wherein the precooling system is configured to receive the gaseous hydrogen from the hydrogen source and cool the gaseous hydrogen to a temperature between 75 K and 100 K, wherein the precooling system comprises a primary refrigeration system and a secondary refrigeration system, wherein the liquefaction system is in fluid communication with the precooling system and is configured to liquefy the gaseous hydrogen received from the precooling system to produce liquid hydrogen, wherein the liquid hydrogen storage tank is in fluid communication with the liquefaction system and is configured to store the liquid hydrogen received from the liquefaction system.

A hydrogen feed stream is introduced into a primary refrigeration system of a precooling system and cooling the hydrogen stream to a first precooling temperature. From there, the precooled hydrogen stream is then introduced to a secondary refrigeration system of the precooling system and cooling the precooled hydrogen stream to a second temperature. Next, the cooled hydrogen stream is then liquefied in the liquefaction system to produce liquid hydrogen. The refrigeration is provided by expansion of a pressurized gaseous nitrogen stream and vaporization of a liquid nitrogen stream that is sourced from a nearby air separation unit.

A SPECTRA process for low-temperature fractionation of air, in which bottoms liquid from an additional second rectification column used to obtain oxygen is evaporated in a second condenser-evaporator. In this second condenser-evaporator, gas that has been evaporated beforehand in a first condenser-evaporator, which is used for condensation of tops gas from a first rectification column, is condensed at the pressure level of the previous evaporation. The invention likewise provides a corresponding plant.

Method and system for removing high freeze point components from natural gas. Feed gas is cooled in a heat exchanger and separated into a first vapor portion and a first liquid portion. The first liquid portion is reheated using the heat exchanger and separated into a high freeze point components stream and a non-freezing components stream. A portion of the non-freezing components stream may be at least partially liquefied and received by an absorber tower. The first vapor portion may be cooled and received by the absorber tower. An overhead vapor product which is substantially free of high freeze point freeze components and a bottoms product liquid stream including freeze components and non-freeze components are produced using the absorber tower.