Palm Fruit Threshing in Palm Oil Mill

Threshing is the pivotal mechanical stage in a palm oil mill where the Fresh Fruit Bunches (FFB) are separated into individual palm fruits and empty stalks. Occurring immediately after sterilization, this process utilizes high-speed mechanical agitation—typically within a rotating drum thresher—to strip the softened fruits from their bunches via centrifugal force and impact. By efficiently isolating the oil-bearing fruit from the Empty Fruit Bunches (EFB), threshing ensures that only the high-value raw material proceeds to the digestion and extraction phases, directly impacting the mill’s overall oil recovery rate and operational productivity.

Threshing uses strong vibration to make separation of palm fruit from palm bunches. Raw materials after sterilization are sent to bucket elevator through damp car, and elevated into threshing machine. Palm fruit separates from bunches, sent to next section elevator through screw conveyor. Empty bunches through conveyor and charger, are transported to certain place for further treatment by car.

The equipment of threshing in Palm Oil Mill

The threshing station in a palm oil mill utilizes specialized mechanical equipment to separate individual palm fruits from their bunches. The setup varies depending on the mill’s capacity, ranging from simple manual-assist tools for small-scale operations to fully automated, high-capacity drum systems.

Rotating Drum Thresher: The most common industrial solution, this is a large cylindrical drum (often 1.2 to 2.4 meters in diameter). It uses internal lifters or blades to agitate and drop sterilized bunches as the drum rotates at approximately 18–25 rpm.

Fixed Drum/Vibrating Thresher: Uses intense vibration or stationary impact mechanisms to separate fruit. This is often used in medium-scale plants where a rotating drum may not be optimal for the layout.

Simple/Manual Stripper: Employed in micro-mills, this inexpensive setup often uses a simple mechanical frame where workers manually beat or strip the bunches.

Fruit Bar Conveyor/Screw Conveyor: Transports the isolated fruits from beneath the thresher to the next stage (digestion).

Empty Fruit Bunch (EFB) Conveyors: Horizontal and inclined conveyors that remove the stripped stalks for waste processing or use as biomass.