A method for recovering helium from a feed gas mixture comprising helium, carbon dioxide and at least one of methane and nitrogen, and wherein at least a part of the feed gas mixture is subjected to a separation sequence including a membrane-based separation and an adsorption-based separation forming a helium product, wherein the the membrane based separation is performed using a first membrane separation step and a second membrane separation step, the membrane based separation and the separation sequence includes no further membrane separation steps, the adsorption based separation is performed using a pressure swing adsorption step, at least a part of the feed gas mixture is subjected to the first membrane separation step forming a first retentate and a first permeate. A corresponding arrangement is also provided.

In a process for the scrubbing of a gas stream, liquid (7) from the scrubbing tower (K) is vaporized (E1) in order to cool ambient air (19) which is subsequently used to cool water (25), producing cooling water (27) to be used upstream or downstream of the scrubbing process.

A purification arrangement has a purification device comprising a housing which in turn comprises at least one substrate adapted to guide said hydrogen gas and to store impurities in the hydrogen gas; a hydrogen gas feeding guide; a hydrogen gas discharging guide; a regeneration gas feeding guide; a regeneration gas discharging guide; a gas guiding assembly adapted to assume each one of the following conditions: a hydrogen gas guiding condition in which each one of said hydrogen gas feeding guide and hydrogen gas discharging guide is in fluid communication with said at least one substrate, a regeneration gas guiding condition in which each one of said regeneration gas feeding guide and said regeneration gas discharging guide is in fluid communication with said at least one substrate.