Camellia seed oil refining

The vast mountainous rural areas are rich in tea seeds, many of which are processed on site. Tea seed oil is mainly processed by alkali refining, which can not only remove acidity and impurities, but also some pigments and odors, meeting the requirements of edible oil. The main equipment for the refining process of tea seed oil includes crude oil storage, alkali refining neutralization, water washing tank, filter machine, soap foot separation and conveying pump, alkali solution tank, etc.

① After the crude oil pump is pumped into the neutralization tank, it is measured and stirred evenly. Samples are taken for acid value analysis, and the amount of alkali added is calculated. In some cases, the excess alkali amount needs to be calculated.

② Adjust the initial temperature of the oil to around 30 ℃. The alkaline temperature in summer is the oil temperature at that time, and it should be appropriately increased in winter.

③ The concentration of alkali solution for neutralization is generally 12-18 ° Be. The actual concentration of alkali added is 12-14 ° Be for those with less than 10 acid values, and 16-18 ° Be for those with more than 10 acid values. When adding alkali, a cross tube is used, and three rows of holes with a diameter of 3mm are drilled alternately from three directions at a 40 ° angle. When spraying alkali solution, it is required to add it in about 20 minutes. Quickly stir at a speed of 60-70r/min.

④ After heating up and adding alkali, continue stirring for 15 minutes to mix the oil and alkali evenly. The alkali will initially combine with the free fatty acids in the oil, and then start heating up at a rate of 1 ℃ per minute. When the temperature reaches 50 ℃, carefully observe the separation of oil and soap. If the oil and soap are significantly separated and the soap particles become coarser, stop heating. When the temperature rises to 50 ℃, the speed slows down to 30-40 r/min. After reaching the final temperature, continue stirring for 10 minutes. Observe the separation of oil and soap, stop stirring in a timely manner, and let the soap feet sink quickly. Then, let the soap feet settle still. If there is a floating surface on the soap feet, add water or salt water that is at or above the same temperature as the oil to make the soap feet floating on the surface sink.

⑤ The static sedimentation time shall not be less than 4 hours, if the sedimentation time is too short. The soap particles suspended in the oil cannot sink to the bottom in time, which makes it difficult to wash with water. It is better to have a longer sedimentation time without affecting the yield, so that the soap particles are tightly packed and the oil content is low.

⑥ Wash the neutral oil in the neutralization pot by pumping it from the shaking tube into the washing pot for washing. When washing with water, the oil temperature should be 85 ℃, and the temperature of salt water or clean water should be above 90 ℃. Generally, 4% salt water should be used for 2-3 times of washing. It is required to release the wastewater from the last washing, which should be clean and clear, to complete the washing. Wastewater should be drained completely to avoid affecting drying.

When washing with water, both the oil temperature and water temperature should be high, and the water temperature should be higher than the oil temperature. The temperature difference between them should not be too large, otherwise emulsification will occur, making it difficult to separate oil and water and increasing refining consumption.

⑦ After the oil has been dried and washed with water, it is dried. When the product pot is opened for drying, the temperature is increased indirectly by steam. When the temperature rises to 100 ℃, the oil is returned, that is, the oil at the bottom of the pot (due to the inability of the snake tube at the bottom of the pot to heat it up, the moisture is difficult to evaporate) is pumped onto the surface of the pot, allowing its moisture to evaporate. At the same time, use compressed air to blow air intermittently. When the temperature rises to 118-120 ℃, stop heating and hold for 1 hour to allow the moisture to evaporate as much as possible. If vacuum drying is used, when the vacuum degree reaches 8936Pa, the temperature is 105 ℃, and there is no water carbon monoxide on the glass mirror, then the drying is complete.

⑧ When filtering, the oil temperature should not be too high, otherwise there will be more impurities in the filtered oil and the filter cloth will be damaged quickly. The pressure of the filtered oil should not be too high, usually around 1.5kgf/cm2. Use two layers of filter cloth, one layer of white canvas and one layer of fine white cloth, to ensure the quality of oil filtration.

After the oil is dried, cool it down. If there is enough time, cool it down with air, which usually takes 14 hours. If there is not enough time, use cold water for cooling. Cooling time: 1 hour in winter, 2 hours in summer, and filter press when the temperature drops to 80 ℃. Then measure the filtered finished oil and store it in the warehouse.

⑨ After the soap feet are pumped into the soap foot pot, they are heated for salt precipitation. If the soap feet are thick, salt water is added. If the soap feet are thin, reinforcement salt or concentrated salt water is added. The soap feet are boiled to above 85 ℃ before the oil can be separated from them. Skim the upper layer of clean oil, then boil and skim again, trying to recover the oil in the soap feet, and then pump the soap feet into the soap foot pool. If conditions permit, centrifuges can also be used to separate neutral oil and soap feet.