Stage 1: Pre-treatment - Pressing and Granulation
Pressing and Crushing Yeast:
The yeast liquid from the fermenter, after centrifugation and washing, enters a filter press to form lumps of high-moisture (approximately 65%-70%) pressed yeast.
Stage 2: Primary Drying - Pre-drying and Granulation
Entering the Pre-drying Bed: The crushed, wet yeast fragments are evenly fed into the first-stage dryer (also known as the pre-drying bed).
Initial Moisture Reduction: After primary drying, the yeast moisture content decreases from approximately 70% to approximately 25%-35%. At this point, the yeast is dry but still retains some plasticity.
Stage 3: Secondary Drying - Main Drying
Entering the Main Drying Bed: The yeast granules, after pre-drying and granulation, are conveyed to the second-stage dryer. The yeast moisture content is further reduced to approximately 8%-10%.
Stage 4: Cooling and Post-treatment
Cooling: The hot yeast granules exiting the main drying bed need to be cooled immediately.
Simplified Process Flow Diagram: Yeast Block Pressing → Crushing → Primary Drying (High-Temperature Pre-Drying & Granulation) → Secondary Drying (Low-Temperature Main Drying) → Cooling → Vibrating Screening → Packaging → Finished Product
