When selecting edible oil processing equipment, the choice between a single-screw oil press and a twin-screw oil press often leaves investors weighing the options repeatedly. Most comparison articles stop at general statements such as “single-screw is cheaper, twin-screw is more efficient,” but overlook a more important question: In cold pressing applications, how large is the advantage of twin-screw, and how quickly can the extra investment be recovered?

This article answers these two questions from three dimensions: cold-pressing phosphorus content, specific energy consumption, and investment payback, using academic research and industry data.

I. Working Principle: Forced Conveying vs. Friction Conveying

Single-screw oil presses have only one rotating screw shaft inside the pressing chamber. Oilseeds enter through the feed inlet and are pushed forward as the screw rotates. The pressing chamber volume gradually decreases, pressure on the oilseeds increases, and oil is squeezed out.

The core feature of this design is structural simplicity, but material conveyance inside the pressing chamber mainly depends on friction. For soft, dehulled oilseeds (such as dehulled rapeseed kernels or dehulled sunflower seeds), the friction coefficient drops sharply, causing material to slip inside the pressing chamber and greatly reducing pressing efficiency.

Twin-screw oil presses have two intermeshing screws in the same press cage, creating a forced positive conveying mechanism. The counter-rotation of the two screws generates a combined shearing and squeezing force, and the oilseeds are repeatedly crushed and pressed in the intermeshing zone. This “positive displacement pump” working principle means that pressing efficiency no longer depends on friction between the material and the pressing chamber, fundamentally solving the slipping problem with soft oilseeds.

II. Cold Pressing Quality: Phosphorus Content Difference Determines Refining Cost

Cold pressing places much higher demands on equipment than hot pressing. Because there is no high-temperature cooking pretreatment, oilseeds are pressed directly at ambient temperature, the friction coefficient of the material is low, and single-screw machines often perform poorly in cold pressing applications.

But the real challenge of cold pressing is not oil yield—it is phosphorus content.

Phospholipids are naturally occurring colloidal substances in oils. During cold pressing, if the pressing temperature is not properly controlled, a large amount of phospholipids can enter the oil, increasing oil loss in subsequent degumming and refining processes. Industry research clearly shows the decisive effect of temperature on phosphorus content: doubling the oil press head temperature from 60°C to 120°C increases phosphorus content sharply from 9 mg/kg to 28 mg/kg.

Because twin-screw pressing uses a positive displacement conveying mechanism, it generates far less friction heat than single-screw pressing. In cold pressing of dehulled oilseeds, the phosphorus content from twin-screw pressing is only one-quarter that of commercial single-screw pressing. Pilot-scale data for cold-pressed tea seed oil further confirms this advantage: at 6.0% incoming moisture, twin-screw cold pressing achieved a residual oil content of only 3.6% in the cake, an oil yield of over 90%, and a maximum pressing chamber temperature not exceeding 60°C.

The impact of phosphorus content on refining cost is direct. Physical refining requires feed oil phosphorus content below 5 ppm, ideally below 3 ppm. The lower the cold-pressing phosphorus content, the simpler the subsequent degumming process and the lower the refining loss. For oil mills positioned in premium cold-pressed oils, the twin-screw advantage in this area means less refining loss and higher finished oil yield.

III. Specific Energy Consumption: A Ninefold Difference

Oil yield is not the only measure of pressing efficiency. Energy consumption per unit of oil produced—the mechanical energy consumed to produce one kilogram of oil—better reflects the true operating cost of the equipment.

Isobe et al. (1992) conducted comparative experiments using dehulled sunflower seeds. Twin-screw pressing achieved an oil yield of 94%, while laboratory-scale single-screw pressing achieved only 20%.

In terms of energy consumption, the specific mechanical energy consumption of twin-screw pressing was only 0.14 kWh/kg oil, compared with 1.25 kWh/kg oil for single-screw pressing—twin-screw unit energy consumption was one-ninth that of single-screw.

Overall, twin-screw pressing consumes over 80% less energy per unit of oil than single-screw, meaning that at the same output, the electricity cost of twin-screw is only one-fifth to one-ninth that of single-screw.

IV. Investment Payback Calculation: The Math for a 50 TPD Peanut Oil Mill

After understanding the differences in cold-pressing quality and energy consumption, the core question remains: How quickly can the extra equipment investment in twin-screw be recovered?

The following calculation uses a medium-sized oil mill processing 50 tons of peanuts per day.

Base Assumptions

• 300 operating days per year
• Peanut oil content: 45%
• Crude oil selling price: approximately $1,200/ton
• Single-screw equipment investment: approximately $80,000 (estimated at 60–70% of twin-screw price)
• Twin-screw equipment investment: approximately $180,000 (based on global average twin-screw oil press price of $23,000 per unit, multiple units configured)

Annual Revenue Comparison

V. Three-Dimensional Decision Matrix: Selecting Based on Your Actual Situation

Different oil mills vary greatly in feedstock characteristics, capacity scale, and product positioning. A single recommendation that “single-screw suits small scale, twin-screw suits large scale” is too rough. The following decision matrix provides more precise selection guidance from three dimensions: daily capacity, feedstock type, and product positioning.

Core selection principle: If you produce conventional hot-pressed oil for the mass market, single-screw still has a cost advantage below 20 TPD. But if your product positioning is premium cold-pressed oil or specialty oil, the twin-screw advantages in phosphorus content control and refining loss are sufficient to cover the incremental investment in a short period.

VI. Huatai Intelligent Equipment Group’s Oil Press Solutions

Huatai Intelligent Equipment Group has over 38 years of experience in oil pressing equipment manufacturing and can provide a full range of solutions from single-screw oil presses to twin-screw oil presses:

Single-screw oil presses: Simple structure, low investment, easy maintenance—suitable for conventional hot pressing in small oil mills and household workshops. Huatai’s single-screw models feature optimized screw pitch design to ensure smooth feeding and stable oil output.

Twin-screw oil presses: Counter-rotating twin-screw design with self-cleaning function—suitable for cold and hot pressing of dehulled oilseeds, high-oil-content seeds, and specialty oilseeds. Huatai’s twin-screw models are equipped with hydraulic pressing systems and PLC automatic control, allowing precise adjustment of pressing chamber pressure to ensure stable oil yield and minimum residual oil in cake.

From equipment selection and process design to installation, commissioning, and personnel training, Huatai provides complete turnkey project services and has served customers in multiple countries and regions worldwide. If you are planning an oil processing project, please contact Huatai Intelligent Equipment Group for an oil press selection solution tailored to your feedstock characteristics and capacity requirements.

References

The data and case studies in this article are compiled from the following sources:

• Isobe et al. (1992): Comparative study on oil yield and energy consumption of twin-screw pressing of dehulled sunflower seeds, included in a HAL Science review
• GCIRC 1991 Congress: Study on twin-screw presses for cold pressing of rapeseed (phosphorus content, temperature data)
• Li et al. (2014): Pilot-scale trial of twin-screw pressing of tea seed oil (residual oil, vitamin E retention data), published in Transactions of the Chinese Society of Agricultural Engineering
• Uitterhaegen & Evon: Review on twin-screw extrusion technology for vegetable oil extraction, published in HAL Science
• QYResearch (2025): Global twin-screw oil press market report (production, average price, growth rate data)
• Huatai Intelligent Equipment Group: Twin-screw oil press technical data and project cases

To verify specific data sources, please contact the Huatai Group technical team for relevant reference materials.