A freeze drying system having a nozzle operated at a setpoint pressure to generate fluid product drops for freezing in a freezing chamber of a freezing vessel. The freezing chamber includes an inner wall that defines a cavity and an outer wall having an inlet that extends from a location on the outer wall that is lower than an outlet. A cooling fluid flows through the inlet, cavity and outlet to form a freezing zone. A drying chamber having sloped shelves receives frozen particles from the freezing chamber. A heating element is associated with each shelf that heats the frozen particles to promote sublimation. Vibration elements located outside the drying chamber vibrate the shelves causing the frozen particles to move from shelf to shelf to form freeze dried product.

Disclosed is a spray-freeze drying (SFD) apparatus for continuous drying of microalgae. The apparatus includes a main chamber connected to a collector chamber and a compressor, designed to freeze fine droplets of microalgae and collect frozen particles. A drying chamber, positioned downstream of the main chamber, is coupled with a vacuum pump and an electromagnetic radiation source to remove moisture from the frozen microalgae, resulting in dried particles. The dried microalgae are then collected in a designated collection chamber. Additionally, a method is disclosed for continuous drying of microalgae using the SFD apparatus. The method involves spraying microalgae suspension as fine droplets towards a cold surface particle collector in the main chamber, freezing and collecting the particles, transferring them to the drying chamber, and removing moisture through the activation of the electromagnetic radiation source and vacuum pump, followed by collecting the dried microalgae in the collection chamber.