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Bleaching--Oil Mill Plant

Bleaching--Oil Mill Plant
The neutralized oil at 90-110°C is sprayed into the bleach earth oil mixer. Here it is dried and mixed with bleaching earth. The bleaching earth is automatically dosed by the hermetic Earth Proportioning System directly from the Bleach Earth Feed Hopper into the Bleacher via a pipe located below the oil spray to prevent dust from entering the vacuum system. The Earth Dosing System is based on two automated butterfly valves with an intermediate dosing chamber. The valves are sequenced by an adjustable timer system in the control panel. 
Then the slurry comes into the Bleacher, which is equipped with three steam agitated compartments to ensure proper mixing and retention time so that the colour bodies and oxidizing materials, etc. in the oil are gradually absorbed by the earth.
The oil/earth mixture is pumped through one of the Bleaching Filters followed by one of the alternating Polishing Filters where the earth and solid impurities are retained. 
The Bleaching Filters operate alternately so that one unit is always working while the other one is cleaned.  The Bleaching Filter cleaning cycle consists of pressurizing the bleaching filter with steam until the main liquid volume has been discharged and then continuing the blowing of steam via the separator so that the cake is properly deoiled. The residual oil (heel) is then discharged to the Bleacher before opening the Bleaching Filter and vibrating off the dry cake onto a conveyor belt or cart.
The Bleaching Filter is then closed and evacuated. The clean Bleaching Filter is filled and pressurized with bleached oil and pre-coated.  It is maintained under circulation until the flow has been switched from the other Bleaching Filter.