A process line (300) for the production of freeze dried particles under closed conditions comprising at least a spray chamber (302) for droplet generation and freeze congealing of the liquid droplets to form particles and a bulk freeze dryer (304) for freeze drying the particles the freeze dryer (304) comprising a rotary drum for receiving the particles. Further a transfer section (308) is provided for a product transfer from the spray chamber (302) to the freeze dryer (304). For the production of the particles under end to end closed conditions each of the devices (302 304) and of the transfer section (308) is separately adapted for operation preserving sterility of the product to be freeze dried and/or containment.
