In the refining process of edible oil, dewaxing is a crucial step, especially for some specific oils such as rice bran oil, sunflower oil and corn oil. The main purpose of dewaxing is to remove natural wax from oil, so as to improve the transparency and stability of products at low temperature. This process not only affects the appearance of oil products, but also directly affects their storage and use performance.

The core principle of dewaxing process is to use the difference of melting point between oil and wax to remove wax by low temperature crystallization and solid-liquid separation. The specific process flow can be divided into several key steps:

The first stage is heating and dissolving. At this stage, the oil is heated to a temperature sufficient to completely dissolve the wax. For example, sunflower seed oil needs to be heated above 70℃. This process ensures that all waxes are in a dissolved state for subsequent cooling and crystallization.

Followed by gradient cooling. At this stage, it is very important to control the cooling rate. By gradually lowering the temperature (for example, 2℃ to 0.5℃ per hour and then to 1-2℃), wax can be uniformly crystallized in oil. The uniformity of these crystals directly affects the subsequent separation effect.

Then the crystal strengthening stage. At this stage, the crystallization time is prolonged by slow stirring (10-15 rpm), which generally takes 4 to 72 hours. This process makes the grains grow gradually and reach the size that is easy to separate.

Finally, the filtration and separation stage. Use filter press or centrifuge to separate solid wax from liquid oil, so as to get clear and transparent oil. This process not only removes excess wax, but also retains the nutritional components of oil.

The whole dewaxing process needs the cooperation of multiple devices, including cooling system, heat exchanger, crystallization tank, crystal growth tank and filter. These devices work together to ensure the efficiency and stability of dewaxing process.

The refined dewaxing process not only improves the quality of edible oil, but also prolongs its shelf life, providing consumers with higher quality products. The development and perfection of dewaxing technology has undoubtedly brought new opportunities and challenges to the edible oil industry.