How to Improve Oil Yield in Soybean Extraction —— Practical Tips from QIE Group

How to truly improve soybean oil extraction rate? A practical sharing from an engineer.

Having worked in the edible oil processing industry for over a decade, I've participated in the construction of soybean oil plants ranging from 5 tons to thousands of tons per day. Whenever clients ask, "How can we extract a few more kilograms of oil?", my answer is always: oil extraction is not a crude process, but a refined science. For a medium-sized oil plant, every 1% increase in oil yield can translate to hundreds of thousands of yuan in additional profit annually—this is achieved through the precise coordination of raw materials, equipment, processes, and experience.

I. Raw Material Processing: Laying the Foundation for Oil Extraction

1. Cleaning: The "hidden synergy" of removing impurities.

Dirt, metal shavings, and moldy particles in soybeans can accelerate wear and tear on oil presses, leading to a decrease in oil yield of approximately 5%-8%. The QIE Group recommends a three-stage cleaning process:

• Magnetic separation + vibrating screen : effectively removes iron impurities and large particles.
• Gravity destoner : Separates stones from light impurities (such as straw fragments).
• Air separator : Removes empty shells, dust and other tiny impurities.

After upgrading its cleaning system, a partner factory reduced the impurity content from 3% to 0.5%, lowered equipment maintenance costs by 40%, and steadily increased the oil yield by 2.3 percentage points.

2. Softening and Disruption: Precise Destruction of Cellular Structure

After crushing soybeans to a particle size of 2–3 mm, adding 7–8% water for softening can increase the cell wall rupture rate by more than 30%. Our independently developed intelligent crusher can automatically adjust the crushing force according to the moisture content of the raw materials, avoiding the powdering problem caused by over-crushing and ensuring maximum subsequent pressing efficiency.

II. Equipment Selection: Matching is more important than price

We never recommend "one-size-fits-all" equipment; instead, we customize solutions based on the customer's production volume, budget, and refined oil grade.

⚙️ It's worth noting that the thickness of the rolled billet directly affects the oil release efficiency. The billet thickness should be maintained between 0.25-0.35mm. If it's too thick, the oil will have difficulty seeping out; if it's too thin, too much powder will be generated, affecting solvent penetration. Regularly calibrating the roll gap and cleaning the scraper are key to ensuring continuous and stable oil output.

👉Further Reading: Which is more profitable, solvent extraction or pressing of soybean oil?

III. Process Optimization: Details Determine Success or Failure

Oil extraction is like cooking; if the heat, time, or proportions are slightly off, the taste will be different.

Temperature and moisture control: This is the core of the pressing process. Typically, the steaming and roasting temperature is set at around 115℃, with moisture maintained at 5%–7%. At this temperature, the protein undergoes moderate denaturation, the oil channels are unobstructed, and the oil's fluidity is significantly improved. One customer, in pursuit of faster production, raised the temperature to 130℃, resulting in excessive protein coagulation, "locking in" the oil, and consequently reducing the oil yield by 1.5%.

Leaching process parameters: In the leaching stage, the material-to-liquid ratio (W:W) is recommended to be controlled at 1:0.8–1.4, the leaching time at 30–45 minutes, and the solvent temperature at 60–70℃. Excessively high temperatures increase the risk of volatilization, while excessively low temperatures reduce extraction efficiency.

Another often overlooked but highly effective step is expansion treatment . This involves subjecting the rolled billet to a short-time, high-temperature treatment using an extrusion puffing machine. This not only disrupts the cell structure but also deactivates lipases, preventing an increase in acid value. Data from multiple projects show that expansion increases leaching efficiency by an average of over 12%.

👉Further reading: How is soybean oil made?

IV. Energy Saving and Intelligentization: Making Oil Extraction More Efficient and Sustainable

Modern edible oil processing equipment has moved from "mechanical drive" to "intelligent control".

• ✅ Automated system: Real-time monitoring of temperature, pressure, and flow rate, automatically adjusting process parameters to reduce human error.

• ✅ Waste heat recovery system: The heat energy from the steaming, frying and desolventizing processes is used for preheating the raw materials, reducing overall energy consumption by 15%-20%.

• ✅ Modular production line: Enables continuous production from cleaning, billet rolling, steaming and roasting to pressing, and supports future capacity expansion and upgrades.