Cottonseed oil is an oil extracted from cottonseed. The traditional cottonseed oil extraction process involves pressing or extraction. The common cottonseed oil processing flow: cottonseed - cleaning - shelling - shell kernel separation - embryo rolling - high moisture steaming - pre-pressing - solvent extraction.
Cottonseed oil contains a large amount of essential fatty acids, among which linoleic acid has the highest content, which can reach 44.0-55.0%. In addition, cottonseed oil also contains 21.6%-24.8% palmitic acid, 1.9-2.4% stearic acid, 18%-30.7% oleic acid, and 0-0.1% arachidic acid. Cottonseed oil can be used for cooking and consumption. It can generally produce soap, glycerin, ink, lubricating oil, and pesticide solvents in industry.
To improve the oil yield, oil, and cake quality, we use screening and air separation methods to remove impurities in cottonseed. The cotton seeds are first screened to absorb some dust and short lint. Then they are air separated, which can not only remove various impurities in the cotton seeds but also reduce the lint content of the cotton seeds.
Although cotton seeds are cleaned to remove some lint, they still contain a lot of short lint. Therefore, to increase the oil yield and reduce the wear of equipment, the cotton hull must be removed before oil production. Huatai uses a centrifugal sheller machine, which can more efficiently separate the cottonseed hull and kernel. And it can absorb the short lint, thereby improving the production environment.
The thickness of cottonseed flakes also has a direct impact on extraction. Generally speaking, the thinner the flakes, the faster the leaching speed and the lower the residual oil rate. For this reason, we use a high-pressure hydraulic flaking machine to control the thickness of the flakes to 0.25~0.30mm. This will not increase the powder content of the flakes, but will also facilitate the leaching of the solvent.
Since cottonseed hulls contain a high content (39%~52%) and cottonpol (0.8%~1.3%). We need to use a vertical cooker to cook the cottonseeds and adjust the temperature and moisture content of it(moisture content 4-6% temperature 110-115℃). This will reduce the cottonpol content in the raw cotton oil and improve the overall quality.
Pressing is the key step in extracting cottonseed oil. According to different pressing methods, divide into hydraulic pressing and screw press. The hydraulic pressing places the blank in the press and precipitates the oil from the cells by high pressure. Screw pressing uses the rotation and pushing action of the screw shaft to continuously squeeze and rub the blank in the press chamber, thereby precipitating the oil.
Huatai YZYX120J series cottonseed oil expeller can produce 7t/d, with oil yield up to 82% and dry cake as low as 6.5%. It also has automatic temperature control and water cooling functions to maintain optimal pressing conditions, prevent nutrient loss, and improve oil quality.
GET A QUOTEThe solvent extraction is a method of separating oil from cottonseed by using the difference in the selective solubility of solvents for oil and cottonseed solid phases. During the extraction process, the solvent (e.g. petroleum ether) is fully mixed with cottonseed powder or crushed cottonseed to dissolve the oil in the solvent. Then the solvent is separated from the oil by filtering, evaporating, and other steps to finally get cottonseed oil.
Huatai's oil solvent extraction technology not only increases the oil rate but also improves the quality of the oil. At the same time, the solvent can be recycled and reused, reducing production costs.
The main purpose of degumming is to remove phospholipids and other colloid substances in cottonseed oil. These substances may affect the stability and taste of the oil in subsequent processing. First, we need to add a certain amount of water to the cottonseed oil and slowly heat it to 70-80°C. Then, add 0.05-0.1% concentrated sulfuric acid or phosphoric acid as a catalyst and keep the temperature for 15-20 minutes. The purpose of this step is to react free fatty acids with water to form a colloid-like hydrophobic substance. Last, let the mixture stand and separate the colloid on the upper layer and the oil on the lower layer.
After degumming, usually carries out deacidification. The main purpose is to remove free fatty acids in cottonseed oil. In this process, we can add alkali (such as sodium hydroxide solution) to neutralize. After the reaction, wash the soap stock to remove the neutral oil. In addition, the deacidification step can be directly in the post-degumming treatment or be carried out independently. It depends on the design of the refining process.
The main purpose of bleaching is to remove pigments from cottonseed oil to improve the color and appearance of the oil. First, we need to heat the degummed (or deacidified) cottonseed oil to 110-120°C. Second, add 0.5-1.5% of an adsorbent such as activated carbon or clay. Then, stir for 30-60 minutes to allow the adsorbent to fully absorb the colored substances in the oil. Finally, remove the adsorbent by filtering to obtain decolorized oil.
The main purpose of deodorization is to remove odorous substances in cottonseed oil, such as volatile fatty acids, aldehydes, ketones, etc., to improve the taste and flavor of the oil. First, we need to heat the decolorized oil to 240-260℃. Then, distill it under vacuum conditions to make the volatile substances evaporate with water vapor. This step needs to be carried out in a deodorization tower to ensure the safety and efficiency of the operation.
Usually, we use "dry fractionation" to fractionate cottonseed oil. Its principle is in the absence of organic solvents, the melted oil is slowly cooled. Until the triacylglycerol with a higher melting point is selectively precipitated, filtered, and separated for crystallization.
For example, the high melting point triacylglycerol in the oil is crystallized at 5.5°C, and this process is called "winterization". The separated stearin can be used to produce margarine. The wax in the oil is crystallized at 10°C, which is called dewaxing. At this time, the equipment used is a crystallization tank. After winterization and dewaxing, cottonseed oil will not become turbid when refrigerated.
High degree of automation and continuous operation, saving labor.
Low residual oil rate in the pre-pressed cake, facilitating solvent penetration.
Multiple extractor options and an advanced mineral oil system.
Energy-efficient with a negative pressure evaporation system.
High-quality oil and meal with a low residual oil rate.
Embark on a journey through the fascinating process of cottonseed oil production with Huatai Oil Machinery, China's leading manufacturer. Our video will guide you through our comprehensive engineering design, showcase the state-of-the-art machinery we supply, and highlight our hands-on installation services.
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