In the preparation of oilseeds for solvent extraction, the soybean needs to be cleaned and conditioned to the correct temperature and moisture. This first steps in processing of soybeans is to properly prepare the soybean for dehulling.Here after, hulls are to be removed to both increase the protein content of the final meal product and also to improve the efficiency of the solvent extraction process. Grounded hulls can be re-introduced in the meal if low protein meal is needed.
The level of protein content required in the final meal will mainly make the choice of type of dehulling (warm, hot or cold**).Correctly dehullled beans will be send for flaking to make thin flakes and rupture the cells containing soybean oil.
Eventually, on request, flakes can be expanded (partially), cooled and dried before finally transported to solvent extraction plant. This will mainly improve percolation and draining, thus extraction.
From daily warehouse or silo, soybean is conveyed into the preparation line. The purpose of cleaning is to remove impurities, for improving quality of final product.
Moisture and temperature of soybean are adjusted by Vertical Conditioner, so that soybean can be easy to be shaped. The process aims to achieve high dehulling rate and low protein denaturation.
3. Cracking and Dehulling
The purpose of cracking and dehulling is to improve protein content and reduce fiber content of soybean meal. In addition, it can enhance extracting efficiency and reduce residual oil contained in the hulls.
The purpose of flaking section is to destroy the cells of soybean and increase the surface area, in order to improve the efficiency of expanding and solvent extraction. Flaking Mill is designed to flake the broken soybean into thins flakes (thickness from 0.3 to 0.4mm). Flakes thickness can be adjusted by adjustment of pressure between rolls. Soybean flakes will be conveyed to the solvent extraction plant.
According to the local market of the meal, it is optional for expanding. Expansion can change the internal structure of soybean, reduce the powder, and increase permeability, so that we can reduce solvent and steam consumption of the whole plant.
The temperature of soybean after expanding is above 100℃, the moisture is over 12%. Due to of the evaporable feature of solvent, we need to cool the materials before solvent extraction.
6. Hulls Crushing
The purpose of soybean hulls crushing is to change bulk density and sense of hulls for subsequent processing of aging and pelleting sections. The granules of crushed soybean hulls should not differ too much from which of crushed soybean meal. So the quality of finished soybean meal will not be affected by blending such crushed soybean hulls while achieving the purpose of adjusting protein content in the finished meal.
7. Aging and Pelleting
The main purpose of bean hulls aging is to sterilize crushed soybean hulls. The direct steam and soybean hulls are evenly mixed under a certain temperature and time to achieve the purpose of sterilizing and enzyme deactivation. Then the moisture and temperature of soybean hulls are reduced by dry hot air, so as to be subsequently added to soybean meal or directly pelleted.
The main purpose of pelleting section is to increase the bulk density and fluidity of soybean hulls, which is beneficial for later transportation and other processing.
- Oils & Fats
- Starch & Derivatives
- Meal Fermentation
- Evaporation & Crystallization