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.

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.

Disclosed herein are systems and processes for removing heavies during the liquefaction of a natural gas. The processes include dissolving the heavies in the natural gas by adding external natural gas liquid (NGL), followed by a staged removal of the natural gas liquid (NGL) and dissolved heavies.

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.

To provide a process for separating hydrocarbons capable of recovering ethane or propane, including improved cold heat recovery enabling a reduction in compressor power. A process for separating hydrocarbons, in which a residual gas enriched with methane or ethane and a heavy fraction enriched with a lower volatile hydrocarbon are separated, includes: a) partially condensing the feed gas by cooling using the residual gas and another refrigerant as a refrigerant, followed by vapor-liquid separation; b) depressurizing and supplying the liquid obtained from step (a) to the distillation column; c) expanding a part or all of the gas obtained from step (a) by an expander to cause partial condensation, followed by vapor-liquid separation; d) feeding the liquid obtained from step (c) to the distillation column after using it as the further refrigerant in step (a); e) feeding a part or all of the gas obtained from step (c) to the distillation column; and f) obtaining the residual gas from the top of the distillation column and the heavy fraction from the bottom of the distillation column.

A method includes: recovering and compressing a head stream coming from a separation column, to form a stream of compressed purified natural gas; liquefying the stream of compressed purified natural gas in a liquefaction unit to form a stream of a pressurized liquefied natural gas; flash expanding of the stream of pressurized liquefied natural gas and recovering in a storage; recovering and compressing of a flow of flash gas coming from the expanding; separating the flow of compressed flash gas (132) into a fuel stream and a recycle stream; cooling and expanding the recycle stream, then introducing the cooled and expanded recycle stream at a head stage of the separation column.

Integrated systems are provided for the production of higher hydrocarbon compositions, for example liquid hydrocarbon compositions, from methane using an oxidative coupling of methane system to convert methane to ethylene, followed by conversion of ethylene to selectable higher hydrocarbon products. Integrated systems and processes are provided that process methane through to these higher hydrocarbon products.

A system and process that are configured to prepare incoming hydrocarbon feedstocks for storage. For incoming ethane gas, the embodiments can utilize a plurality of vessels to distill the incoming feedstock to vapor and liquid ethane that is suitable for storage. The embodiments can direct the vapor to a demethanizer column that is downstream of the vessels and other components. The process can include stages for distilling an incoming feedstock at a plurality of vessels to form a vapor and a liquid for storage; directing the vapor to a demethanizer column; and circulating liquid from the demethanizer column back to the plurality of vessels.

One or more specific embodiments disclosed herein includes a method for separating hydrogen from an olefin hydrocarbon rich compressed effluent vapor stream, employing a single heat exchanger, multiple gas-liquid separators, multiple expander/compressor sets, and a rectifier attached to a liquid product drum.