Food Processing

Overview

To optimize product drying, such as biltong production, we can reduce the trial and error time by providing a drying approach that tackles key parameters in drying food. Temperature, humidity, airflow, and handling methods are key considerations.

Sample Design: 20ft Container Size Dry Room

Air Flow

• Recommended Velocity: 2-4 m/s through the product.
• Purpose: To create turbulence on the product skin for faster drying.
• Recirculation: Utilize a false ceiling with 1.8m high hanging trays to enhance airflow.
• Dimensions:
  • Height: 1800mm of racking
  • Width: 2300mm
  • Length: 6000mm
  • Face Area: 4m²

Maximum Airflow

• Calculation: 4 m/s (velocity) x 4m² (face area) = 16,000 l/s
• ESP: 200 Pa estimated

Dehumidification Capacity

• Product Quantity: 2000kg/day
• Moisture Removal: 10%
• Estimated Drying Time: 24 hours
• Capacity Average Calculation: 2000kg x 10% x 24h = 8.3 kg (L)/h

Heat Load

• From DST R061R Dehumidifier to Room: 7kW
• Evaporation Heat Load: 0-5.6kW average (8.3 kg/h evaporation), maximum estimate 7kW
• Cooling Load: 7kW desiccant heat generation from drying 8.3 kg/h, plus summer heat gain 2kW

Method: Product Drying with Desiccant Dehumidifier – Batch Drying

The use of desiccant dehumidifiers for product drying involves integrating the dehumidifier in a bypass to recirculated air. The heat given off by the desiccant is often sufficient to heat the room, thus cooling equipment is needed to avoid overheating. As different products each have their own drying characteristics, it is crucial to understand their drying profile to make an initial selection. Initial evaporation rates are usually substantially higher than the calculated average.

Steps for Effective Drying:

1. Airflow Management: Ensure that the airflow velocity through the product is between 2-4 m/s to create necessary turbulence for efficient drying.
2. Temperature Control: Monitor and adjust the temperature to maintain optimal drying conditions without overheating the product.
3. Humidity Regulation: Use the desiccant dehumidifier to maintain low humidity levels, ensuring efficient moisture removal from the product.
4. Handling Methods: Implement proper handling techniques to ensure even drying and prevent product damage.
5. Initial Measurements: Conduct simple measurements of weight change over time to understand the drying trend and moisture loss rate.
6. Oversizing Considerations: Use initial tests to help determine the appropriate equipment sizing, accounting for higher initial evaporation rates.

By adhering to these guidelines, food processing facilities can optimize their drying processes, leading to improved product quality and reduced drying times.

Additional Considerations

• Recirculation: Implementing a false ceiling and strategic placement of hanging trays can significantly improve air recirculation within the drying room.
• Moisture Load Calculation: Accurately calculate the moisture load to ensure the dehumidification system is adequately sized.
• Regular Monitoring: Continuously monitor the drying process and make adjustments as needed to maintain optimal conditions.

Implementing these comprehensive strategies for food dehumidification will result in efficient drying processes, higher product quality, and improved overall production efficiency.

  *SAMPLE ONLY time profile of product moisture content and suggested
room temperature control, cooler at end of cycle to avoid
overheating dry product.

Food-(PDF)