SRS’ dewaxing unit utlizes the same process as the degumming unit. See SRS’ degumming process technology This system is used to remove the wax that is commonly found in corn oil. During ethanol production, ten percent of the residual byproduct is corn oil. The problem with this corn oil is it is very high in FFA (Free Fatty Acids) and needs to be pretreated. Read more about SRS’ pretreatment system
SRS employs a dewaxing process that is a non acidic water based process.
Some vegetable oils, such as sunflower or corn oil,contain waxes which crystallize at lower temperatures and result in turbidity in the oil. Wet winterization in combination with neutralization is suitable for removing these waxes.
The crude oil is initially neutralized, meaning that, in order to condition the gums, an acid is initially added and the free fatty winterization acids are then neutralized with caustic soda. After the soapstock is separated in the first separator, the oil is conveyed to the actual Winterizing stage.
A small quantity of caustic soda is again added in order to set a specific residual soap content in the oil. This soap is subsequently required as a wetting agent
during crystallization in order to bind the waxes to water. After mixing of caustic and oil, the product is cooled to the crystallization temperature. Wax crystals
form in two to four crystallization tanks connected together. Due to the soap in the oil, these wax crystals bind to the water, which is added to the crystallizers.
In order to reduce the viscosity, the oil is carefully heated and conveyed to a separator which continuously separates the waxy water. The oil is washed again
in order to further reduce the residual soap content. For this purpose, the oil is heated, the corresponding quantity of hot water is added; after intensive mixing,
it is separated in a further separator. Vacuum drying
then takes place.