In the oil processing industry, the design of the pretreatment system is crucial for ensuring high - quality oil production and stable operation. This article focuses on the design of large - scale oil mill pretreatment systems with daily production capacities ranging from 30 to 5000 tons, specifically analyzing the optimization of crushing and steaming parameters according to the characteristics of cottonseed and sunflower seed.
The pretreatment system mainly includes cleaning, crushing, softening, flaking, and steaming. Each link has a significant impact on the subsequent oil - solvent extraction process.
Cleaning is the first step, aiming to remove impurities such as stones, sand, and stems from the raw materials. For cottonseed, due to its relatively large size and the presence of lint, a combination of screening and air - separation is often used. The impurity content after cleaning should be controlled below 0.5%. For sunflower seed, which is smaller and more uniform in size, a more precise screening process can be adopted, and the impurity content should be less than 0.3%.
Crushing can increase the surface area of the raw materials, facilitating subsequent processing. The crushing degree of cottonseed is usually controlled so that the particle size is between 2 - 4 mm. However, sunflower seed is more brittle, and the crushing particle size can be slightly smaller, around 1 - 3 mm. The moisture content of the raw materials also affects the crushing effect. Generally, the moisture content of cottonseed before crushing is controlled at 9% - 11%, and that of sunflower seed is 7% - 9%.
Softening can adjust the moisture and temperature of the raw materials to make them more suitable for flaking. For cottonseed, the softening temperature is generally 60 - 70°C, and the moisture content is increased to 12% - 14%. For sunflower seed, the softening temperature is 55 - 65°C, and the moisture content is adjusted to 10% - 12%.
Flaking further increases the surface area of the raw materials and destroys the cell structure. The thickness of cottonseed flakes is usually 0.3 - 0.5 mm, while that of sunflower seed flakes is 0.2 - 0.4 mm.
Steaming is to adjust the moisture and temperature of the flakes to meet the requirements of oil - solvent extraction. For cottonseed, the steaming temperature is 100 - 110°C, and the moisture content is reduced to 3% - 5%. For sunflower seed, the steaming temperature is 95 - 105°C, and the moisture content is controlled at 2% - 4%.
Cottonseed has a hard outer shell and contains gossypol, which requires special attention during processing. The high - pressure steaming process can effectively remove gossypol. Sunflower seed, on the other hand, has a high oil content and a relatively thin shell. The process should focus on protecting the oil quality and improving the extraction rate.
There was an oil mill that processed cottonseed. Due to improper crushing parameters, the particle size was too large, resulting in a low oil extraction rate in the subsequent extraction process. After analysis, the crushing process was adjusted, and the particle size was controlled within the appropriate range. As a result, the oil extraction rate increased from 30% to 35%. Another case involved a sunflower seed oil mill. The steaming temperature was too high, which led to the oxidation of the oil and a decrease in quality. By reducing the steaming temperature and optimizing the time, the oil quality was significantly improved.
To help users better understand the process, this article is equipped with process flowcharts, temperature - humidity curves, and equipment comparison tables. These data visualizations can reduce the difficulty of understanding and enhance professional credibility. For example, the temperature - humidity curve can clearly show the changes in temperature and moisture content during the steaming process, helping engineers make more accurate parameter adjustments.
Selecting an advanced pretreatment system is crucial for ensuring high - quality oil production and stable operation of the enterprise. By optimizing the crushing and steaming parameters according to the characteristics of cottonseed and sunflower seed, the efficiency and stability of oil - solvent extraction can be effectively improved. If you want to learn more about advanced oil mill pretreatment systems and get professional solutions, click here.
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