How to Extract Soybean Oil

Soybean oil is one of the most commonly used vegetable oils in the world. Its versatile properties make it suitable for a wide range of applications, including cooking, baking, and frying. As the demand for soybean oil continues to increase, more investors are looking to establish soybean oil processing plants. However, starting a soybean oil factory requires a thorough understanding of the production process, including the various processing steps, plant site selection, capital investment, and supporting processing equipment. In this essay, we will explore the two common production methods for soybean oil: pressing and extracting, and discuss how to choose the right equipment for each process.

Introduction of Soybean Oil Production Process

Pressing Technology

The pressing method uses mechanical extrusion to produce soybean oil from oilseeds. The standard soybean oil pressing production process includes cleaning, crushing, softening, embryo rolling, steaming, pressing, and filtering. Each of these steps is critical to ensuring the quality of the final product. For instance, cleaning involves removing any foreign matter, such as stones and dirt, from the raw materials. Crushing, on the other hand, breaks the oilseeds into smaller pieces to increase the oil yield.

Softening is another essential step in the pressing process. It involves heating the crushed oilseeds to a specific temperature to loosen their structures, making it easier to extract the oil. The embryo rolling step is where the softened oilseeds are rolled into flakes, which are then subjected to steaming. Steaming is necessary to ensure the complete destruction of enzyme activity in the flakes. After steaming, the flakes are ready for pressing, which is the actual extraction process. The pressed soybean oil can then be filtered and sold directly, or further processed according to market requirements.

If the processing capacity of soybean oil is less than 10 tons per day, an integrated oil press with automatic temperature control and vacuum filtration can meet the pressing requirements of soybean oil. However, for processing capacities above 10 tons per day, a soybean oil pressing production line is more suitable. The use of a production line improves the quality of the oil and increases the yield.

Extraction Technology

The extracting method, on the other hand, uses a solvent to dissolve the oil in the oilseeds. Oilseeds with an oil content of about 20% are more suitable for extraction. For oilseeds with a higher oil content, a pre-press machine can first be used to lower the oil content in the oilseed cake to about 15%. This allows for better leaching and increased oil yield.

Before extraction, pretreatment of the oilseed raw materials is necessary. Pretreatment includes cleaning, steaming, frying, and puffing, among others. The objective of pretreatment is to improve the quality of the oil and to increase the yield. After pretreatment, solvent extraction can be carried out. The resulting product is crude soybean oil and a cake meal. The residual oil rate in the cake is less than 1%, making it suitable for animal feed processing.

However, crude soybean oil needs to undergo refining before it can be sold or consumed. Refining involves removing impurities, such as free fatty acids, phospholipids, and pigments, from the crude oil. This process ensures that the oil meets the quality standards required for commercial use.

When the processing capacity of oilseeds exceeds 20 tons per day, it is more cost-effective to use extraction methods to produce soybean oil. This is because extraction is more efficient and results in higher yields. Additionally, extraction reduces the production cost of soybean oil, resulting in more profits.

The Advantages And Required Equipment of Soybean Oil Extraction Methods

Choosing the right equipment is crucial to the success of a soybean oil production business. The choice of equipment depends on the production method and the processing capacity. The following are some key factors to consider when selecting equipment and technology for soybean oil extraction.

Extraction equipment:

The equipment used in soybean oil extraction includes oilseed pretreatment equipment, oil extraction equipment, and oil refining equipment. Oilseed pretreatment equipment includes cleaning screens, crushers, flaking machines, and steam cookers. Oil extraction equipment includes solvent extractors, desolventizers, and evaporators. Oil refining equipment includes degumming tanks, bleaching towers, and deodorization towers.

Extraction technology:

The extraction technology used in soybean oil extraction includes batch extraction, semi-continuous extraction, and continuous extraction. The batch extraction method is suitable for small-scale production, while the semi-continuous and continuous extraction methods are suitable for large-scale production.

Solvent selection:

The solvents used in soybean oil extraction include hexane, ethanol, and isopropanol. Hexane is the most commonly used solvent for soybean oil extraction because it has a high extraction efficiency, is easily recovered, and is relatively inexpensive.

Environmental considerations:

Soybean oil extraction is a highly polluting process, and therefore, environmental considerations are critical when selecting equipment and technology. When choosing equipment, look for those that have low energy consumption, low emissions, and high efficiency.

Quality of soybean oil:

The quality of soybean oil is crucial when choosing equipment and technology. The extraction method and equipment used can affect the color, flavor, and nutritional value of the final product.

Steps for Soybean Oil Extraction

The following are the basic steps for soybean oil extraction:

Cleaning: The first step in soybean oil extraction is to remove impurities and foreign materials from the soybean seeds. This is done using screens, magnets, and air classifiers.

Cracking and flaking: The soybean seeds are then cracked and flaked to break them down into small pieces. This increases the surface area of the seeds and makes it easier for the solvent to extract the oil.

Conditioning: The flaked soybeans are then conditioned by heating them to a specific temperature and adding moisture. This helps to loosen the oil from the cells of the soybean and makes it easier to extract.

Extraction: The conditioned soybeans are then fed into the extractor, where they are mixed with a solvent, such as hexane, to extract the oil.

Desolventizing: The oil and solvent mixture is then separated, and the solvent is removed using a desolventizer.

Distillation: The solvent is recovered by distillation, leaving behind crude soybean oil.

Refining: The crude soybean oil is then refined to remove impurities and improve its quality. This involves processes such as degumming, bleaching, and deodorizing.

Soybean oil extraction is a complex process that requires careful consideration of equipment and technology. The two most common production methods for soybean oil are pressing and extracting. While pressing is suitable for small-scale production, extraction is more suitable for large-scale production. To extract soybean oil, you need to choose appropriate equipment and technology based on factors such as extraction equipment, extraction technology, solvent selection, environmental considerations, and the quality of the soybean oil. Finally, the basic steps for soybean oil extraction include cleaning, cracking and flaking, conditioning, extraction, desolventizing, distillation, and refining. With careful planning and consideration, you can successfully extract soybean oil and start a profitable soybean oil production business.