Abstract: An overhead recycle process apparatus (100) comprises a heat exchange arrangement (116, 118, 120, 146, 150, 198) and a separator (110) in fluid communication with an absorber (104) and a de-ethaniser (106), the absorber (104) having a reflux inlet port (164). An ethane rectifier (170) in fluid communication with the de-ethaniser (106) is also provided, the de-ethaniser (106) being arranged to provide cooling by heat exchange to an overhead stream path (194) of the ethane rectifier (170). The ethane rectifier (170) comprises a reflux drum (182) having an ethane outlet port (184) and a vapour phase outlet port (185) in fluid communication with the reflux inlet port (164) of the absorber (104).

Abstract: A method for recovering a helium product fraction (6) from a nitrogen- and helium-containing feed fraction (3) is described, wherein the nitrogen- and helium-containing feed fraction (3) is partially condensed (E1), separated into a first helium-enriched fraction (5) and a first nitrogen-enriched fraction (8) and the former is cleaned again in an adsorptive manner. According to the invention, the separation is carried out in a separation column (T), which is supplied with the first nitrogen-enriched fraction (8) as return flow and with a sub-flow of the second nitrogen-enriched fraction as stripping gas (12), wherein the stripping gas quantity (12) is set such that a third nitrogen-enriched fraction (20), which contains at least 30% of the nitrogen contained in the first nitrogen-enriched fraction (8), can be recovered in the separation column (T).

Abstract: A process for reliquefying a methane-rich fraction, in particular boil-off gas, is described. In this process, a) a methane-rich fraction is compressed to a pressure at least 20% above the critical pressure of the fraction to be compressed, b) liquefied and supercooled, c) depressurized to a pressure in the range from 5 to 20 bar, d) separated into a gaseous nitrogen-rich fraction and a liquid nitrogen-depleted fraction, e) the nitrogen-depleted fraction is depressurized to a pressure in the range from 1.1 to 2.0 bar, f) the gaseous fraction obtained, without being warmed and compressed, is mixed into the methane-rich fraction, and g) the liquid product fraction obtained in the depressurization of the low-nitrogen fraction has a nitrogen content of ?1.5 mol %.

Abstract: The invention relates to a method for cooling a single-component or multi-component stream, in particular a hydrocarbon-rich fraction, by indirect heat exchange with the refrigerant mixture of a refrigerant mixture circuit. The refrigerant mixture is compressed in at least two stages and is separated into a lower-boiling refrigerant mixture fraction compressed to the ultimate pressure of the refrigerant mixture circuit and at least one higher-boiling refrigerant mixture fraction compressed to an intermediate pressure. The latter is pumped (P11) to the pressure of the former and the two fractions are combined before or immediately on commencement of indirect heat exchange.

Abstract: The invention relates to a process for separating off C2+-hydrocarbons from a feed fraction containing essentially nitrogen and hydrocarbons, wherein a) the feed fraction (1, 20) is partially condensed (E1, E1?, E3) and separated by rectification (T) into a C2+-hydrocarbon-rich fraction (11) and a C2+-hydrocarbon-depleted fraction (2), b) the C2+-hydrocarbon-depleted fraction (2) is partially condensed (E2) and separated into a liquid fraction which forms at least in part the reflux (3) for the separation by rectification (T), and a C2+-hydrocarbon-depleted gas fraction (4), and c) the C2+-hydrocarbon-depleted gas fraction (4) is separated in a double-column process (N) into a nitrogen-rich fraction (8?) and a methane-rich fraction (7?). According to the invention, the liquid fraction obtained in process step b) is fed (10) at least in part likewise to the double-column process (N) and separated therein into a nitrogen-rich fraction (8?) and a methane-rich fraction (7?).