NOVELTY - Separating (P1) gaseous product from feed stream having contaminants involves (i) providing the feed stream; (ii) cooling the feed stream at which slurry stream is formed which comprises solid contaminant, liquid phase contaminant and the gaseous product; (iii) introducing slurry stream into upper part of separation device which allows gaseous product to flow upwardly and solid contaminant and liquid phase contaminant to flow downwardly; (iv) removing the gaseous product from upper part of the device; and (v) removing stream having liquid phase contaminant from lower part of the device.    USE - For separating at least part of gaseous product including methane or hydrogen and/or carbon monoxide from feed stream comprising contaminants (claimed).    ADVANTAGE - The use of the inlet units brings highly effective separation of gaseous product from a feed stream that comprises contaminants. The risk of ice formation on the inner wall of the separation device and erosion of the inner wall can attractively be reduced when compared with the use of a conventional cyclonic inlet. The process enables purification of natural gas comprising acidic contaminants, such as carbon dioxide, resulting in purified natural gas comprising low levels of contaminants, especially of sulfur contaminants.    DETAILED DESCRIPTION - Separating (P1) at least part of a gaseous product from a feed stream which comprises contaminants, involves (i) providing the feed stream; (ii) cooling the feed stream to a temperature at which a slurry stream is formed which comprises solid contaminant, liquid phase contaminant and the gaseous product; (iii) introducing the slurry stream as obtained in step (ii) via several tangentially directed inlet units, with a small inlet angle, into an upper part of a separation device, to create a swirl of the slurry stream which allows at least part of the gaseous product to flow upwardly and solid contaminant and liquid phase contaminant to flow downwardly; (iv) removing at least part of the gaseous product from the upper part of the device; and (v) removing a stream comprising liquid phase contaminant from a lower part of the device. INDEPENDENT CLAIMS are included for the following:    (1) a cryogenic separation device (D1) for carrying out the process (P1) comprising outlet unit for removing at least part of the gaseous product from an upper part of the device; outlet unit for removing the stream comprising liquid phase contaminant from a lower part of the device; several tangentially directed inlet units for introducing the slurry stream comprising solid contaminant; liquid phase contaminant and the gaseous product into an upper part of the device, with a small inlet angle, where the inlet unit are arranged below the outlet unit for removing at least part of the gaseous product from the device; and each inlet unit comprises expansion unit or communicates with units arranged upstream of the inlet unit, preferably which comprises at least two inlet units, preferably 2-8 inlet units, especially where at least two inlet units are located at the same horizontal level at circumferential spaced points, even especially which comprises 4 inlet units which are located at the same horizontal level at circumferential spaced points;    (2) a purified stream containing at least part of the gaseous product obtained by the process (P1); and    (3) liquefying a feed stream involving purifying the feed stream, followed by liquifying the feed stream by known methods.