Cotton Seed Oil Refining Process
Cottonseed oil is also the main cooking oil. However, wool cotton oil contains gossypol (content about 1%), colloid and wax (content varies depending on the shell content of the oil-making cotton germ), and its quality is poor, so it is not suitable for direct consumption, and its refining process is relatively complicated.
1. Rough refining cotton oil refining process (continuous)
lye soft water
↓
Filtration of crude oil-→preheating-→oil-alkali ratio-→mixing reaction-→desoaping-→washing-→dehydration-→drying-→cotton oil
↓
Soapstock Wastewater
Operating conditions: impurity in filtered crude oil is not more than 0.2%, lye concentration is 20~28°Bé, excess alkali is 10%~25% of theoretical alkali, desoaping temperature is 70~95°C, drum flushing water addition is 25~1001/h, oil inlet pressure 0.1~0.3 MPa, oil outlet back pressure 0.1~0.3 MPa, washing temperature 85~90°C, washing water addition is 10%~15% of oil volume, dehydration back pressure 0.15 MPa, the drying temperature is not lower than 90°C, the operating absolute pressure is 4.0kPa, and the filtration temperature of the refined oil is not higher than 70°C.
2. Refining edible oil refining process
phosphoric acid lye soapstock lye
↑ ↓
Filtration of crude oil-→preheating-→mixing-→oil-alkaline ratio-→mixing reaction-→desoaping-→mixing
↓
Filtration←-distillation deodorization←-filtration←-adsorption decolorization←-dehydration←-washing←-soap removal
↓
Refined cooking oil Water vapor Waste clay Adsorbent Wastewater Soft water Soapstock
Key points of operation: operating conditions before alkali refining are the same as crude oil refining, re-refining lye concentration is 6~12°Bé, addition amount is 1%~3% of oil volume, re-refining temperature is 70~90°C, and oil outlet back pressure is 0.15 MPa. The operating conditions of washing, decolorization and deodorization are similar to those of peanut oil refined edible oil. If degreasing is performed after deodorization, the grade of the finished oil will be refined refrigeration table oil (salad oil). The technological process after the deodorization process is:
┌→ soft fat
Deodorized cotton oil-→cooling and crystallization-→growing crystals-→filtering-┤
└→ cold table oil
Operating conditions: Cooling crystallization temperature 5~10°C, temperature difference between cooling water and oil about 5°C, crystallization time 8~12 hours, crystal growth time 10~12 hours.
