Solvent extraction is one of the most efficient oil processing technologies available today. Whether it is a rotary extractor or a loop extractor, both use the principle of oil and organic solvents dissolving each other to extract oil from oilseeds. The oilseeds are crushed, pressed into flakes or expanded, and then thoroughly contacted with organic solvents such as n-hexane in the extractor. After separating the miscella, you obtain crude oil.
Solvent extraction technology is characterised by high efficiency, high oil yield, and a high degree of mechanisation. Solvent extraction equipment can effectively reduce the residual oil content in the extracted meal to below 1%, which is why it is widely adopted by large-scale oil processing enterprises.
Among the various types available, the rotary extractor and the loop extractor are the two most commonly used oil solvent extraction equipment in edible oil plants. So, what is the difference between them? And which one is right for your oil mill?
What Is a Rotary Extractor?
A rotary extractor (also known as a Rotocel extractor) is a continuous solvent extraction device that uses a rotating basket or cell design to carry out immersion extraction. The extractor is driven by a rack driving system, and its unique rotor balancing process ensures less power consumption, lower maintenance costs, and less noise.
Key Features of a Rotary Extractor:
- Suitable for high-oil-content oil cakes: The rotary extractor is more suitable for corn germ cake, peanut cake, sunflower seed cake, cottonseed cake, and other oilseeds with high oil content and a large degree of powder.
- Ideal for smaller processing capacities: It is used for solid-liquid extraction of vegetable oils and fats in oil plants, especially those with smaller processing capacities.
- Flexible and stable operation: The adjustment of solvent extraction time and processing capacity is more convenient and stable.
- Reliable sealing: A reliable material seal is formed in the feeding hopper to prevent gas from the solvent extractor into the pretreatment workshop.
- Simple structure: The whole machine has a simple structure, convenient operation, and a high operation rate.
- Reduced meal fines: The rotating cell design at the top bin level makes it easy to perform immersion extraction and reduce the number of meal fines in the miscella, improving crude oil quality by reducing scaling in the evaporation system.
What Is a Loop Extractor?
A loop extractor (also known as a loop-type extractor or ring extractor) features a chain driving system, a frequency-controlled motor speed, and a unique circular structure. It runs smoothly with low power consumption and low maintenance costs.
Key Features of a Loop Extractor:
- Suitable for bulk oilseeds: The loop extractor is more suitable for soybean, rapeseed, cottonseed, and other bulk oilseeds.
- Excellent extraction effect: The unique Bengala spraying method ensures a good extraction effect.
- High processing capacity: It offers large processing capacity with a uniform material layer.
- Efficient miscella utilisation: The loop extractor provides high utilisation of miscella, large concentration increments, fast spray penetration, fast draining, and low solubility of wet meal.
- Low solvent consumption: The advanced miscella circulating schematic design decreases the need for fresh solvent input. The residual oil in the meal is reduced, improving the miscella’s concentration.
- Low material bed: The material bed is low and uses percolation leaching, with materials being turned at curved sections to prevent dead spots.
- Energy saving: Energy is saved by reducing evaporation requirements.
Rotary Extractor vs Loop Extractor: Key Differences at a Glance
| Feature | Rotary Extractor | Loop Extractor |
|---|---|---|
| Suitable Oilseeds | Corn germ cake, peanut cake, sunflower seed cake, cottonseed cake (high oil content, high powder degree) | Soybean, rapeseed, cottonseed (bulk oilseeds) |
| Processing Capacity | Especially suitable for smaller capacities | Large processing capacity |
| Drive System | Rack driving system | Chain driving system |
| Extraction Method | Immersion extraction with rotating cells | Percolation leaching with low material bed |
| Miscella Quality | Reduced meal fines, less scaling in evaporation | High miscella concentration, fast drainage |
| Sealing | Reliable material seal prevents gas leakage | Micro-negative pressure prevents solvent escape |
| Structure | Simple structure, easy operation | Circular structure, chain-driven |
How to Choose the Right Solvent Extraction Equipment for Your Oil Mill?
Selecting between a rotary extractor and a loop extractor depends on several factors related to your specific oil processing needs:
1. Consider your raw materials
- If you are processing pre-pressed oil cakes with high oil content (such as peanut cake, sunflower seed cake, or cottonseed cake), the rotary extractor is the better choice.
- If you are processing bulk oilseeds (such as soybeans, rapeseed, or cottonseed), the loop extractor is more suitable.
2. Consider your processing capacity
- For smaller processing capacities, the rotary extractor is particularly well-suited.
- For larger processing capacities, the loop extractor offers higher throughput.
3. Consider your operational priorities
- If you prioritise simple structure, easy operation, and flexible adjustment of extraction time and capacity, the rotary extractor is a good fit.
- If you prioritise high miscella concentration, fast drainage, and energy savings through reduced evaporation, the loop extractor offers distinct advantages.
Our Solvent Extraction Equipment Solutions
We provide a complete range of solvent extraction equipment, including both rotary extractors and loop extractors, to meet the diverse needs of edible oil plants. Our equipment features:
- Low residual oil rate: Effectively reduces residual oil in meal to below 1%
- Low power consumption: Advanced rotor balancing and chain drive systems ensure energy efficiency
- Low maintenance costs: Durable design with minimal maintenance requirements
- Stable operation: Reliable sealing and automated speed control
- Customised solutions: We help you select the optimal equipment based on your oilseed type, processing capacity, and site conditions
Whether you are planning a new solvent extraction workshop or upgrading your existing line, our engineering team can provide the most suitable solution for your project.
Contact us today for a free consultation and equipment quotation tailored to your oil processing needs.