A pre-press squeezer (expeller) mechanically extracts 60-70% of a seed's available oil before it reaches solvent extraction, leaving a cake with 12-18% residual oil for the solvent stage to finish. It's the mechanical half of a two-stage extraction process, positioned to reduce the workload on the solvent extraction plant downstream.
Why pre-pressing before solvent extraction
High-oil-content seeds carry more oil than a solvent extraction plant can efficiently process directly — running full-oil-content material through the extraction column requires more solvent and larger equipment than necessary. A pre-press screw or hydraulic press squeezes out the bulk of the available oil mechanically first, so the solvent extraction stage only has to deal with the harder-to-reach 12-18% remaining in the cake. This reduces the capacity requirements on the solvent extraction side and improves overall plant efficiency.
How the mechanical stage works
The press design — screw press or hydraulic press depending on the configuration — applies continuous pressure to conditioned or cooked seed, forcing oil out while maintaining the structural integrity of the resulting cake. That cake structure matters: it needs to hold together well enough to be handled and fed into the solvent extraction stage without breaking down into fines. Integrated oil collection and filtration systems capture the pressed oil as it's expelled, and heavy-duty steel construction handles the continuous mechanical load of round-the-clock operation.
Specifications
- Press type: screw press or hydraulic press
- Oil extraction: 60-70% of available oil
- Cake residual oil: 12-18%
- Capacity range: 50-500 TPD
- Construction: heavy-duty steel
When pre-pressing makes sense
High-oil seeds like soybean, sunflower, rapeseed, and canola are the typical candidates for a pre-press stage ahead of solvent extraction, since they carry enough oil to make the mechanical step worthwhile. Lower-oil-content feedstocks may go directly to solvent extraction without pre-pressing at all — the decision comes down to whether the oil content justifies adding a mechanical stage before the chemical one.
What the cake needs to survive the next stage
Cake structure isn't just a byproduct of pressing — it's an input requirement for the drier cooler and solvent extraction stages that follow. A cake that breaks down into excessive fines during pressing creates the same channeling problems in the extraction column that over-thin flakes cause, so the press needs to apply consistent, continuous pressure rather than uneven or excessive force that would compromise structural integrity. Integrated oil collection and filtration built into the machine also matters operationally, since pressed oil needs to be captured cleanly rather than requiring separate downstream cleanup, and continuous operation design keeps the pre-press stage from becoming a throughput bottleneck ahead of the plant's solvent extraction capacity.
Interested in our industrial equipment?
Our engineering team, based in Indore, Madhya Pradesh, India, will recommend the right solution for your plant requirements.
Request a quote