Method for solid-phase extraction of substances present in gas mixtures

Abstract

The invention relates to a method for solid-phase extraction of at least one substance such as NO2, N2O, SO2, H2S or CO2, contained in a gas mixture (11), the method comprising: - a step of cooling (20) the gas mixture containing the substance which will, at low temperatures, pass directly from the gas phase to the solid phase; - a parallel step of producing hydrocarbon snow (250) in a series of ejectors (350); - a step of dispersing this hydrocarbon snow at a temperature lower than that of the triple point of the substance to be anti-sublimated in a column (450) in which the gas mixture containing the substance to be anti-sublimated flows; - a step of sublimating the solid particles of the hydrocarbon, causing the anti-sublimation of the substance contained in the gas mixture; - a step of recovering the substance (5) in the solid phase, at the bottom of the column, in a double storage device (51, 52) operating alternately in recovery mode or in discharge mode of the solid substance.

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