Centrifugal olive oil extraction line: how do decanter and separator work?

Centrifugal separators operate on the basis of centrifugal force (G-force): when crushed olive paste spins at high speed, phases of different densities stratify — lighter oil migrates inward while heavier water and pomace are forced outward. Compared with traditional batch pressing, which is intermittent and difficult to keep hygienic, the centrifugal method delivers continuous flow, stable throughput, and an enclosed system that minimises air contact — a key factor in maintaining oil quality.

A typical centrifugal olive oil line comprises two main pieces of equipment working in series. The decanter handles rough primary separation of the multi-phase olive paste, while the disk-stack separator carries out the polishing step. This combination achieves efficient oil separation while maintaining a one-directional, CIP-cleanable process.

The decanter (horizontal scroll centrifuge) is the heart of the primary separation stage. The conical-cylindrical bowl spins at high speed, generating substantial G-force; inside, a scroll conveyor rotates at a differential speed relative to the bowl. Solid pomace (olive pulp and pits) is continuously conveyed toward the conical end and discharged, while the liquid phase — comprising oil and water — overflows at the opposite end. Depending on configuration, the decanter can separate 2 phases (liquid + pomace) or 3 phases (oil + water + pomace) in a single step.

HAUS designs decanters for food processing lines in AISI 304/316 stainless steel, with bowl diameters of 200–800 mm and flow rates of 1–180 m³/h depending on model. PLC-controlled differential speed between the bowl and scroll conveyor allows operators to fine-tune pomace moisture content and liquid phase clarity to suit each feedstock.

After the decanter, the oil phase still contains a quantity of water and fine solids. This is where the disk-stack separator comes in. The equipment uses a stack of conical discs to split the flow into very thin layers; combined with very high G-force, this separates the fine phase — residual water and solids separate cleanly from the oil — yielding a clearer and more stable finished product.

The core distinction: the decanter excels at solid-liquid separation when solids content is high (the scroll conveyor continuously discharges pomace), while the disk-stack separator specialises in fine-phase separation when solids content is low. In an olive oil line, the two pieces of equipment complement each other: the decanter for primary separation, the separator for polishing.

A centrifugal olive oil extraction line typically follows a series of sequential steps, ensuring one-directional material flow that is easy to control:

Thanks to AISI 304/316 stainless steel construction and hygienic design, the line meets food processing requirements, is easy to clean, and minimises cross-contamination. Using the same working principle, decanters and separators are also used to separate other vegetable oils and fish oil, not just olive oil.