Dewaxing of waxes is the separation process at low temperature, as the temperature decreases, the polarity of the ester bond in enhanced oil wax molecules at less than 30 ℃ (about 0 ℃) i.e. formation of crystallized, forming more stable colloidal system. In this low for some time after the wax crystals agglomerate to form larger solid grains to increase the proportion to form a suspension. Finally, wax separation.
Typical dewaxing process: the oil is slowly cooled to 5-10 ℃, holding at least 6h wax crystals. After crystallization stable, then the oil temperature rise is usually around 15 ℃, in order to reduce the viscosity for easy filtering.
During operation dewaxing process:
The accurate measurement of waxy, fat oils and cold solvent (ethane 18-20 ℃) in proportion (40% oil: 60% solvent) into the mixer. Then, with a pump continuously into the mold in series. Accordance with the conditions set by it slow cooling and crystallization (including raising the grain about 8-10h).
The mold can be divided according to the set time period only 2-5 series. Each comes with stirring (10-13r / min) and is equipped with a special rotating blade mezzanine and slow heat exchange (coolant) to prevent the precipitation of crystals deposited on the cooler wall. After crystallization the suspension, with compressed air directly to a continuous vacuum filter for separation. When the degree of vacuum filtration control in133.2kPa (400mmHg), speed 15r / min, sprayed on the diatomaceous earth precoat drum filter aid if necessary.