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Dingsheng Machine Offers Rice Bran Oil Winterization Dewaxing Technology and a Complete Set of Processing Equipment.

Date:Jun 16th, 2023
Rice bran oil contains a certain amount of wax, and the presence of wax can affect the flowability and transparency of rice bran oil. Therefore, the winterization dewaxing process is employed to remove the wax from rice bran oil, improving its quality and stability. The main principle of winterization dewaxing is to crystallize the wax at an appropriate temperature and remove it through filtration.

First-grade rice bran oil winterization dewaxing process
First-grade rice bran oil has a higher solid fat content, with stearic acid ranging from 1% to 3.8% and palmitic acid ranging from 12% to 18%. The solid fat crystallizes and separates from the oil at low temperatures, causing the oil to become turbid and form solid-liquid layers. Dewaxing is usually carried out after deacidification, as fatty acids tend to solidify before lipids at low temperatures, making dewaxing filtration difficult.

Dewaxing process: After physical refining, the rice bran oil with a KOH value of 1-3 mg/g is cooled to 30°C and pumped into the dewaxing crystallization tank. It is slowly and evenly cooled to 0-2°C over 24 hours and kept at that temperature for 48 hours for crystallization. Slow stirring is used during the crystallization process. The allowed temperature may slightly rise by 2-5°C during crystallization. Then, it is filtered using a pre-coated filter with diatomaceous earth. The pre-coating layer's filter pressure is set at around 0.06 MPa, and the filtration temperature is maintained at 25°C. Gravity filtration is employed, utilizing the natural oil level difference, to avoid the use of high-pressure pumping filtration that could disrupt the fat crystals. After dewaxing and defatting, the physically refined rice bran oil yields around 90% liquid oil and 5%-10% solid fat (containing a small amount of liquid oil).

Alternatively, a two-step crystallization and filtration process can be used. Deodorized rice bran oil is cooled to around 30°C, crystallized for 24 hours, and filtered once with a filter pressure below or equal to 0.35 MPa. The filtered oil is then transferred to the second crystallization tank, where it undergoes a second filtration with a filter pressure below or equal to 0.35 MPa at an oil temperature of no more than 25°C and a crystallization time of 24 hours.

Third and fourth-grade rice bran oil winterization dewaxing process
Dewaxing of third and fourth-grade rice bran oil is carried out before the bleaching process. These oils have a high content of free fatty acids, with a KOH value of around 30 mg/g. The fatty acids have a high melting point, and as the temperature decreases, they solidify first, resulting in a significant increase in oil viscosity. At 20°C, the rice bran oil becomes very thick, making dewaxing filtration challenging. Therefore, the filtration temperature should be equal to or higher than 20°C.

Basic process: After dehydration, the rice bran oil is pumped into a crystallization tank and slowly stirred. The oil temperature is gradually reduced from 70°C to around 25°C within 24 hours. Slow stirring (10-15 rpm) is continued, and the oil is allowed to crystallize for 48 hours. Then, it is pumped into a leaf filter for filtration, with pre-coating of diatomaceous earth before the oil enters the filter. Increasing the filtration temperature can accelerate the filtration speed and reduce the wax content in the filter cake, but it may decrease the transparency of the oil. On the other hand, lowering the filtration temperature decreases the filtration speed but reduces the wax content in the oil, lowers the cloud point, and improves the transparency of the oil. The resulting liquid oil is approximately 90%, and the solid fat is around 5%-10%.

Dewaxing of rice bran oil also has a certain bleaching effect. Production results have shown that the color of Y70 and R20 rice bran oil decreases to Y70 and R12 after dewaxing. This is because brown trivalent iron ions, along with fatty acid chelates and some high-melting-point pigments, crystallize and precipitate at low temperatures, being trapped in the wax during the dewaxing filtration process.

The rice bran oil processing equipment is designed with high-quality materials and advanced manufacturing processes to ensure stability and reliability. These equipment have efficient dewaxing capabilities and are user-friendly, requiring easy operation and maintenance. We provide comprehensive solutions ranging from process design to equipment manufacturing, installation and commissioning, as well as after-sales services. Our team can customize dewaxing equipment based on the specific needs and requirements of our customers. If you have any requirements for rice bran oil dewaxing equipment, please feel free to consult us.

Rice Bran Oil Dewaxing Solution Expert Team:
Justin Han
Email: company@dingmachinery.com
Phone: +86-159 3716 3029
Address: 100M East from the crossings of Jinjiang Road and Huaiyang Road, Shangjie District, Zhengzhou City, China.





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