The invention relates to a process for incorporating sulfur in the porosity of the solid particles of a catalyst for the conversion of hydrocarbons or an adsorbent. This process is carried out off-site in the presence of hydrogen sulfide that is pure or diluted in hydrogen or nitrogen, a process in which said particles are made to rise or fall in a sulfur incorporation zone that comprises at least one vibratory helical coil that is essentially tubular in shape and that comprises at least two turns, whereby said particles are subjected to a temperature profile over the majority of their path in said coil and whereby said particles are brought into contact with at least one fluid on at least one portion of their path.