Decolorization is one of the very important processes in the palm oil refining process. In addition to removing the pigment in the oil, decolorization can also reduce the content of phospholipids, peroxide value, soap content and metal ion content, thereby improving the color of the oil , flavor and improve oxidation stability, providing good conditions for further refining, hydrogenation and deodorization of oil.
At present, the commonly used method for palm oil decolorization is activated clay adsorption decolorization method, which uses clay, a substance with strong selective adsorption, to remove pigments dissolved in oil under certain conditions or disperse them in oil with colloidal particles. pigments and other impurities.
The factors that affect the decolorization effect of palm oil are:
1. Decolorization temperature, the effect is best when the decolorization temperature is around 110°C. In order to prevent condensed water from entering the filter cake and affecting the drying of the filter cake and automatic slag unloading, the temperature of the filter medium must be above 105°C.
2. Decolorization time, the effective decolorization time of oil should be controlled within 20min~30min to ensure the decolorization effect.
3. Absolute pressure. The absolute pressure in the decolorizer should be reduced to 9.3kpa~6.6kpa, that is, vacuum decolorization, which can effectively remove the air in it. Proper and effective stirring can also improve the decolorization effect.