Alkali refining operating temperature initial temperature 30~35 °C, final temperature 60 ~ 65 °C. Lye concentration 16°Bé, the amount of excess alkali added is 0.2%~0.25% of the oil amount. Add saponin, 0.5% of the oil amount (concentration is 40°Bé). The neutralization time is about l h, and the sedimentation separation time is not less than 6 h. Alkali refining washing temperature 85～90°C. The first washing water was dilute saline water (alkali concentration 0.4%), added 0.4% oil containing salt, and added 15% of the oil amount. After washing several times with hot water, the amount of soap in the alkali refining oil is not more than 50 ppm. Decolourization, first vacuum dehydration for 30 min, under temperature 90 °C, operating absolute pressure 4.0 kPa. Then add the activated white clay to decolourize. For 20 min, the amount of white clay added is 2.5% ~ 3% of the oil amount. Decolourization temperature is 90～95 °C, then cool down to below 70 °C to filter. The decolourized filter oil is heated to 100 °C by a vacuum suction deodorization tank formed by a primary and secondary steam jet pump. Then turn on the third and fourth stage steam jet pump and the atmospheric condenser cooling water. The deodorization temperature is not lower than 245 °C, and the absolute pressure is 260-650 Pa. The atmospheric condenser water temperature is controlled at about 30 °C, and the stripping direct steam pressure is 0.2 MPa, the amount of the feed is 8 to 16 kg/t·h. The deodorization time is 3 to 6 hours. After the deodorization is completed, it is cooled to 70 °C and filtered.