Flash Desolventization

Soybean is an excellent raw material for the protein source. For the production of protein concentrates and protein isolates which are needed for the human consumption, high PDI meal is required (PDI value 75).

With conventional method of de-solventising, the HP steam gets condensed during de-solventizing which produces meal of 20 – 30 PDI, that is not suitable for high value products from soybean meal.

The alternative process to get high PDI products from the de-oiled flakes leaving solvent extraction process, is Flash de-solventizing and followed by cooling.

In this process, the de-oiled wet soybean flakes are fed into high velocity stream of superheated solvent vapors at 160°C. The de-oiled flakes enter the tube at 55-60°C with 25 – 35% liquid solvent hexane and 8-10% moisture. The superheated solvent vapors convey the material in a looped tube at velocity of approximately 20-25 meters per second. The specific heat of the superheated solvent vapor stream is utilized to vaporize hexane and remove moisture from the flakes.

About 2 seconds after entering the tube, de-oiled flakes exit the tube at 100 to 105°C with 0.5% liquid hexane and 6% moisture.

The meal at 100°C enters in the specially designed vacuum stripper, where the superheated steam is passed through the meal bed to reduce the residual hexane content below 350 ppm.