What is Solvent Extraction?
Solvent extraction of oil is a highly efficient chemical method that uses a food-grade solvent, typically n-hexane, to dissolve oil from oilseeds, oil-rich materials, and agricultural by-products. In a fully equipped solvent extraction plant, the process achieves an oil recovery rate of 95–99%, far exceeding mechanical pressing.
This technology is widely applied in soybean oil extraction, rice bran oil processing, sunflower seed oil production, cottonseed oil processing, rapeseed oil extraction, and numerous other vegetable oil industries. Due to its high efficiency, low residual oil content, and excellent solvent recovery rates, solvent extraction is recognized as the standard process for global commercial edible oil production.
Solvent Extraction Process
The modern solvent extraction process involves several key steps designed to maximize oil yield and ensure production stability:
1. Feeding and Material Pretreatment
Oilseeds are pretreated into flakes, pellets, or expanded forms to enhance permeability. Proper pretreatment ensures effective solvent penetration into the material.
2. Extraction
The pretreated material is continuously fed into the extractor. Hexane flows through the material bed, dissolving the oil to form a mixture called the oil-solvent mixture.
3. Separation
Following extraction, two intermediate products are produced:
- Wet Meal: The defatted solid is sent to a desolventizer-toaster (DT) to remove solvent, producing high-protein animal feed.
- Miscella: The oil-solvent mixture is distilled in evaporation and stripping columns to recover the solvent and produce crude vegetable oil.
4. Solvent Recovery
Advanced evaporation, condensation, and stripping systems recover over 98% of the solvent, ensuring environmental safety and low operating costs.
5. Crude Oil Processing
The extracted crude oil is then sent to an edible oil refinery plant for degumming, bleaching, deodorization, and final production of edible oil.
Types of Solvent Extraction & Key Equipment
Different raw materials require specific extraction equipment. We offer three types of solvent extraction equipment widely used in oil processing plants globally:
1. Rotary Extractor
Suitable for large-scale solvent extraction plants, enabling continuous production with low solvent consumption. Ideal for soybeans, cottonseed, and rapeseed.
2. Loop Extractor
Gentle material handling protects fragile oil flakes. Flexible for multiple oilseeds, ensuring uniform percolation and high oil yield.
3. Drag-Chain Extractor
Ideal for rice bran, corn germ, and light materials. Compact design, stable operation, high extraction efficiency, and low residual oil content.
These extractors can be optimized based on plant layout, raw material characteristics, and required processing capacity.
Common Raw Materials for Solvent Extraction
Solvent extraction plants can process a wide variety of oilseeds and grains, including: soybeans, rice bran, sunflower seeds, cottonseed, rapeseed/canola, corn germ, peanut cake, sesame cake, palm kernel cake, and other expeller cakes.
Key Features of a Modern Solvent Extraction Plant
When investing in solvent extraction plant, focus on the following characteristics to ensure performance, safety, and profitability:
- High Oil Yield – Optimized extraction technology achieves oil yields up to 99%.
- Efficient Solvent Recovery – Advanced evaporation and stripping systems minimize solvent loss.
- Premium Meal – Gentle desolventization preserves protein quality for animal feed applications.
- Safety Compliance – Design meets international industrial safety and food production standards.
- Automation – PLC control systems ensure stable operation with minimal manual intervention.
From Crude Oil to Finished Edible Oil
Solvent-extracted crude oil contains non-oil impurities such as phospholipids, free fatty acids, pigments, and waxes. Therefore, it must undergo oil refining processes including degumming, neutralization, bleaching, winterization (for certain oils), and deodorization. Huatai provides complete turnkey edible oil production lines covering every stage from seed processing to refining and final filling.
Why Choose Huatai’s Solvent Extraction Plant?
With over 38 years of experience, Huatai designs and manufactures customized solvent extraction systems for industrial-scale oil producers worldwide.
- Expert Engineering—Tailored solutions based on your raw materials, capacity, and site requirements.
- End-to-End Service—From plant design and manufacturing to installation, training, and after-sales support.
- Proven Technology—Reliable performance, low operating costs, and high return on investment.
Huatai’s solvent extraction plants have achieved success. Fully installed in over 30 countries across Asia, Africa, and South America, they serve both large enterprises and medium-sized producers.