The invention relates to a method (100, 200) of obtaining one or more olefins, in which, using an oxidative coupling of methane (10), a gas mixture comprising hydrogen, methane, carbon monoxide and higher-boiling hydrocarbons than methane is formed and is subjected to a low-temperature separation (1-5), characterized in that the low-temperature separation (1-5) is conducted using a rectification column (2) having a first separation region (21), a second separation region (22) arranged above the first separation region (21), and a condenser-evaporator (23), wherein the gas mixture is cooled, fed at least partly as first separation feed into the first separation region (21) and subjected to a first rectification in the first separation region (21) to form a first tops gas and a first bottoms liquid, wherein, using a first proportion of the first tops gas in the condenser-evaporator (23), a condensate which is recycled to the first separation region and, using a second proportion of the tops gas, a second separation feed which is fed into the second separation region (22) are formed, and wherein the second separation feed is subjected to a second rectification in the second separation region to form a second tops gas and a second bottoms liquid.

A process for separating a component mixture comprising essentially hydrocarbons having two or two or more carbon atoms, methane and hydrogen using a distillation apparatus (10) is proposed. Fluid (a, c, e, g, i) from the component mixture is cooled stepwise to a first pressure level, with separation of first condensates (b, d, f, h, j) out of the fluid (a, c, e, g, i) in each case. Fluid (k) from the component mixture that remains in gaseous form thereafter is expanded to a second pressure level in an expander, giving a second condensate (I). Fluid from the first condensates (b, d, f, h, j) is expanded from the first pressure level to the second pressure level and fed together with the fluid from the second condensates into the distillation apparatus (10) which is being operated at the second pressure level. The present invention likewise provides a corresponding separation apparatus.

One aspect of the invention relates to a hydrocarbons fluid liquefaction system, having a first heat-exchange module having a pre-cooling exchanger having a pre-cooling circuit and a plurality of pre-cooling refrigerant circuits for pre-cooling the feed stream through the circulation of an expanded first mixed-refrigerant stream, and a second heat-exchange module having a liquefaction exchanger having a liquefaction circuit and a liquefaction refrigerant circuit for liquefying the feed stream through the circulation of an expanded second mixed-refrigerant stream, wherein each heat-exchange module has thermally insulating walls and a framework that allows the module to be transported and secured, and allows the first heat-exchange module to be stacked on top of the second heat-exchange module.

This specification relates to operating industrial facilities, for example, crude oil refining facilities or other industrial facilities that include operating plants that process natural gas or recover natural gas liquids.

Described herein are methods and systems for the liquefaction of natural gas to produce a LNG product. The methods and systems use an apparatus for separating a flash gas from a liquefied natural gas (LNG) stream to produce a LNG product and recovering refrigeration from the flash gas. The apparatus includes a shell casing enclosing a heat exchange zone comprising a coil wound heat exchanger, and a separation zone. The heat exchange zone is located above and in fluid communication with the separation zone. Flash gas is separated from the LNG product in the separation zone and flows upwards from the separation zone into the heat exchange zone where refrigeration is recovered from the separated flash gas.

A natural gas liquid recovery system includes a cold box and a refrigeration system. The refrigeration system includes a primary refrigerant loop in fluid communication with the cold box. The primary refrigerant loop includes a primary refrigerant including a first mixture of hydrocarbons. The refrigeration system includes a secondary refrigerant loop. The secondary refrigerant loop includes a secondary refrigerant including i-butane. The refrigeration system includes a first subcooler configured to transfer heat between the primary refrigerant of the primary refrigerant loop and the secondary refrigerant of the secondary refrigerant loop. The refrigeration system includes a second subcooler downstream of the first subcooler. The second subcooler is configured to transfer heat between the primary refrigerant and a vapor phase of the primary refrigerant. The cold box is configured to receive the primary refrigerant from the second subcooler.

A process and an apparatus are disclosed for the recovery of components from a hydrocarbon gas stream containing significant quantities of components more volatile than methane (hydrogen, nitrogen, etc.). The gas stream is partially condensed, then the remaining vapor is expanded to lower pressure and supplied to a fractionation tower at a mid-column feed position. The condensed liquid is cooled and divided into two portions. The first portion is expanded to tower pressure, heated by cooling the liquid, and supplied to the tower at a lower column feed position. The second portion is further cooled, expanded to tower pressure, and supplied to the tower at a top feed position. The tower overhead vapor is heated by cooling the second portion. The quantities and temperatures of the feeds to the tower maintain the overhead temperature of the tower whereby the major portion of the desired components is recovered.

A process and an apparatus are disclosed for the recovery of components from a hydrocarbon gas stream containing significant quantities of components more volatile than methane (hydrogen, nitrogen, etc.). The gas stream is partially condensed, then the remaining vapor is expanded to lower pressure and supplied to a fractionation tower at a mid-column feed position. The condensed liquid is cooled and divided into two portions. The first portion is expanded to tower pressure, heated by cooling the liquid, and supplied to the tower at a lower column feed position. The second portion is expanded to tower pressure and supplied to the tower at an upper mid-column feed position. A distillation vapor stream is withdrawn from the fractionation tower below the mid-column feed position and is heated, compressed to higher pressure, and cooled to substantial condensation before it is expanded and supplied to the tower as its top feed.

A method for improving the capacity of an existing air separation unit employing a lost air turbine is provided in which the capacity is increased by operating the existing air separation unit as previously operated, with the exception of collecting the lost air from the lost air turbine, and instead of venting said lost air to the atmosphere, the lost air is compressed in a supplemental air compressor and returned to the air separation unit at a location downstream a front-end purification unit and upstream a booster. This setup advantageously allows for increased production without having to adjust the sizing of the front-end purification unit or main air compressor.

A method for removing heavy hydrocarbons from a feed gas by: feeding, into an absorber, a top reflux stream and a second reflux stream below the top reflux stream, wherein the absorber produces an absorber bottom product stream and an absorber overhead product stream; depressurizing and feeding the absorber bottom product stream to a stripper to produce a stripper bottom product stream and a stripper overhead product stream; cooling and feeding a portion of the absorber overhead product stream back to the absorber as the top reflux stream; and pressurizing and feeding the stripper overhead product stream back to the absorber as the second reflux stream. Systems for carrying out the method are also provided.