The present invention concerns a process for unloading a bed (2) of particulate material from a vessel (1), which comprises inserting a removable and portable extraction pipe (4) into the lower part of said bed, injecting a fluidization gas upwardly into the extraction pipe (4) from the bottom part thereof, along the entire length of the extraction pipe (4), and applying a positive pressure differential between the inlet and the outlet of said extraction pipe.The present invention further concerns a device suitable for implementing such a process.