The present invention relates to a gas-filtering system (1000, 3000, 4000, 5000, 6000) comprising: an input (1100) for the gas, a reactor (1301, 1302, 1303) for filtering the gas at the input (1100) and thus obtaining a filtered gas, an output (1200) for the filtered gas, a vacuum generator (1401, 1402) for generating a vacuum inside the reactor (1301, 1302, 1303), where the vacuum generator (1401, 1402) is configured so as to apply a first predetermined vacuum value (VI) in a first vacuum phase (T2) and so as to apply a second predetermined vacuum value (V2) in a second vacuum phase (T3); the filtering system (1000, 3000, 4000) further comprising a flow controller (1501, 1502, 1503) connected at the output to the reactor (1301, 1302, 1303), where the flow controller (1501, 1502, 1503) is configured so as to block the introduction of the filtered gas into the reactor (1301, 1302, 1303) during the first vacuum phase (T2), and where the flow controller (1501, 1502, 1503) is configured so as to allow the introduction of the filtered gas and/or a second gas into the reactor (1301, 1302, 1303), starting from the output (1200) during the second vacuum phase (T3).