Production method of batch processing palm oil
Batch systems act directly on cooked fruit. Oil is extracted from boiler fruit for clarification in one operation. Vertical retorts use a perforated floor to mash a batch of fruit, then hot water is used to rinse oil and other non-oily solids from the mashed pulp, using the “wet” method. Direct screw presses are designed to mash one batch of cooked fruit while applying pressure to the mashed pulp in another section to expel the palm oil in one operation.
The wet system has the advantage of simplicity and complete leaching of all oily and non-oily solids. The aqueous effluent from the vertical digester goes directly to the clarification stage of the treatment. The amount of water needed to flush the pulp is usually the same as to dilute the viscous oil coming from the mechanical press in preparation for clarification.
When the wash water becomes colder, the oil yield of the wet method will decrease. During the digestion of fruit pastes, in the presence of water, there is an increased tendency to form oil/water emulsions which are difficult to separate from the fibrous mass. If care is not taken to ensure that the digester is fully loaded, the loss of emulsified oil in the fibers can be significant. As a result, vertical flush digesters need to load and unload a specific amount of material and can therefore only be used in batch operations.