Optimizing Screw Press Oil Extraction: A Real-World Case Study from a Mid-Sized Oil Mill

In the competitive world of edible oil production, even a 1–2% improvement in oil yield can translate into significant profit margins for mid-sized manufacturers. This case study explores how one Chinese oil mill—processing both sunflower seeds and sesame—successfully reduced oil residue in press cake by over 35%, while increasing throughput efficiency by 22%, through targeted optimization of pre-treatment processes.

Why Pre-Treatment Matters More Than You Think

The key to consistent high-quality extraction lies not just in the screw press itself—but in what happens before it. In our client’s facility, raw materials were often contaminated with husks, sand, or moisture, leading to uneven feeding, frequent blockages, and elevated oil content in the press cake (initially averaging 12–15%). After implementing standardized cleaning, crushing, and steaming protocols, the average oil residue dropped to under 8%—a result that directly impacted their bottom line.

Tailoring Processes to Crop Type: Sunflower vs. Sesame

What worked for sunflower seeds didn’t work as well for sesame due to differences in lipid structure and moisture retention. For instance:

• sunflower required longer steaming at lower temperatures to avoid premature gelatinization;
• sesame needed precise humidity control during drying post-steaming to prevent cracking and oil loss.

These adjustments weren’t based on guesswork—they came from iterative testing using real-time temperature sensors and lab analysis of press cake samples. The mill now uses a digital logbook system to track each batch’s parameters, enabling continuous refinement.

From Trial to Standard Operating Procedure (SOP)

Once the optimal settings were confirmed, the team created an SOP document accessible via tablet on the production floor. Operators could now reference exact values for each material type instead of relying on memory or experience alone. Within two months, downtime from clogs dropped by 40%, and operator training time was cut in half.

This isn’t just about better machines—it’s about smarter workflows. And when your equipment is running smoothly, your customers notice. One buyer who visited the site reported they’d consider placing a repeat order after seeing the consistency in output quality and waste reduction.