Oil Dewaxing Winterization,Fractionation

Common Raw Oil for Dewaxing, Winterization:Sunflower oil, corn oil, rice bran oil, cottonseed oil and so on.

Cooking Oil Dewaxing Process

Main Steps of Oil Dewaxing Process

Conventional dewaxing is the common oil dewaxing method with the working principle of freezing and then mechanically separating oil & wax without any auxiliary means, the separating methods are usually pressure filtration, vacuum filtration, and centrifugal separation. Conventional dewaxing is the simplest oil crystallization and filtration method.

First of all, the oil crystallization is carried out in the cooling chamber at 0~4℃, after 72 hours’ cooling, the final oil temperature in oil tank is around 6~10℃. The average cooling rate is 2℃/hour at the first 24 hours of cooling period, the cooling rate of next 24 hour is 0.5℃/hour and the last 24-hour’ cooling rate is 1~2℃/hour. Then, the oil and precipitated wax crystals are separated by bag filtration in the filtration room at 15~18℃, and the filtration time is around 10~12 hours. The available filtration bags are polyester card, cotton or cotton fabric, and their filtering speed is polyester card>cotton>cotton fabric.

At present, most of the oil refining plants are cooling, crystallizing and plate filter separating oil from the wax paste. Oil such as sunflower seed oil contains less wax which could be dewaxed by cooling to 10~15℃ in 2 days and then pumping to the plate filter with compressed air. The dewaxing effect is good with a wax content in dewaxed oil is only ten milligrams per kilogram. In general, the conventional dewaxing is simple and cost-effective, but the wax separation is not complete and has a high cloud point which could be through crystallizing filtration for twice.

Main Dewaxing Equipment

1.Cooling system

2.Heat exchanger

3.Crystallizing tank

4.Maturing tank


Precautions for Cooking Oil Dewaxing Machine

1.Before cooling, oil should be heated firstly to make the wax which has been precipitated at room temperature(wax precipitates when room temperature is lower than the crystallization temperature.) completely dissolved in oil liquid, which can enhance the following dewaxing effect.

2.The oil cooling speed should be even which shouldn’t be too fast.

3.After cooling for 72 hours, the crystallized wax need be matured for 12~16 hours to make it grow big.

4.When separating, you can use two plate filters for filtering to keep continuous working.

Common Dewaxing Temperature and Timeare 

Oil product name Crystallization temperature(℃) Crystallization time(hour)
Palm oil 30 8-10
Cottonseed oil 0-10 10-12
Sunflower oil 5-10 4-6
Rice bran oil 5-10 4-6

Oil Dewaxing and Fractionation Distinction

1.Oil dewaxing and fractionation are based on the same principle, but they have different purposes. Dewaxing is by removing wax content to improve the palatability and quality of the oil. While fractionation is by using the differences of glycerol’s melting point and solubility to obtain solid fats & liquid oils from raw material.

2.During oil dewaxing winterization, oil is kept at low temperature for a period of time and then filtered to remove solid impurities that can cause liquid oil become cloudy.

3.Oil fractionation is a modified process, which involves a larger change in the material components, and improve the physical properties of the oil product. For example, fractionated coconut oil contains a large amount of medium-chain fatty acids like caprylic acid (C8) and capric acid (C10) that may lead to modest weight loss and provide several other health benefits.