The STET electrostatic separation process is completely dry, requiring no water or chemicals. Dry electrostatic separation methods offer an opportunity to generate new and more functional plant protein products, including sunflower seed meal with increased protein content for use as a high value animal feed. This protein enriched sunflower seed meal can be used as a non-GMO replacement for soy meal, and add value to sunflower oil crushing operators and feed producers.
A sample of solvent extracted sunflower seed meal was purchased by STET for pilot testing. The sunflower meal was finely milled (dry) into two particle sizes, a coarser feed with a d50 = 70 micron, prepared with a hammer mill and a finer feed with a d50 = 25 micron, prepared with an air classified mill. The dry sunflower seed meal samples were then separated using the STET tribo-electrostatic belt separator. Subsamples of the negatively charged and positively charged products were measured for protein using the DUMAS method.
Finely milled dry sunflower seed meal samples demonstrated excellent separation of protein. For the coarser (d50 = 70 micron) sample, the feed sample containing approximately 39% protein (dry basis) was separated into a product containing 52% protein and a by-product with a 29% protein, in a single pass through the separator. For the finer (d50 = 25 micron) sample, a product with a 54% protein content was generated, with a by-product with 25% protein, in a single pass through the separator.
The tribo-electrostatic belt separator demonstrated the capability to process finely ground sunflower seed meal to significantly upgrade the protein content, making it more valuable as an animal feed. The STET tribo-electric belt separator offers many benefits for processing sunflower meal including continuous operation, a high feed rate of up to 15 tons per hour feed, low energy consumption, ease of operation and high mechanical reliability.