Bag Filter in Shortening Production

Bag Filter in Shortening Production

In shortening production line, a bag filter is a crucial component used to remove impurities, solid particles, and other contaminants from the shortening during the manufacturing process. Here’s how it works and its significance:

Role of Bag Filters in Shortening Production Line

1. Filtration of Impurities
   • Shortening (a semi-solid fat) may contain residual solids, catalyst particles (from hydrogenation), or other contaminants.
   • Bag filters trap these particles, ensuring a clean, high-quality final product.
2. Post-Hydrogenation Filtration
   • If the shortening is hydrogenated (to increase melting point), a nickel catalyst is often used.
   • Bag filters help remove residual catalyst particles after hydrogenation.
3. Post-Bleaching Filtration
   • After bleaching (using activated clay or carbon to remove color and odors), bag filters separate the spent bleaching earth from the oil.
4. Final Polishing Filtration
   • Before packaging, bag filters act as a final polishing step to ensure clarity and purity.

Types of Bag Filters Used

• Mesh Bag Filters – For coarse filtration (e.g., removing large particles).
• Melt-Blown Polypropylene (PP) Bags – For fine filtration (e.g., removing small catalyst residues).
• Stainless Steel Bag Housings – Used for high-temperature applications (common in edible oil processing).

Key Considerations

• Pore Size (Micron Rating) – Typically ranges from 1 to 25 microns, depending on the stage of filtration.
• Material Compatibility – Must withstand high temperatures (up to 100–150°C) and resist oil degradation.
• Sanitary Design – Important for food-grade applications to prevent contamination.

Maintenance & Replacement

• Regular inspection and replacement of filter bags are necessary to prevent clogging and maintain efficiency.
• Automated systems may include pressure sensors to indicate when bags need changing.

Benefits

• Improves product quality by removing unwanted solids.
• Extends the life of downstream equipment (e.g., pumps, heat exchangers).
• Ensures compliance with food safety standards (e.g., FDA, FSSC 22000).