The thesis concerns the process analysis and sizing of a hydrogen generation plant based on AEM (Anion electrolyte/Exchanged membrane) technology, aimed at the study of the process and its components. In the design phase, the under designed plant must use equipment complying with the European ATEX regulation concerning potentially explosive atmospheres, API standards for sizing and installation of safety relieve-devices and PED directive for classifying the pressure equipment according to the increasing danger criteria. The work performed began with a detailed description of a new design with an electrical capacity of 500 kW for the generation of 50 Nm3/h of oxygen and 100 Nm3/h of hydrogen with a purity of 99.999%.