Abstract: Hexane solvents are a family of C6 alkanes that include seven isomers of hexane. They have different boiling points and properties, and can be mixed to form narrow-boiling-range solvents that are suitable for low-temperature oil extraction. This article introduces the advantages of using hexane solvents over conventional solvents, such as energy saving, quality improvement, environmental protection, and safety enhancement. It also discusses the regulatory and technical issues of using hexane solvents, and provides some examples of their industrial applications.
Keywords: hexane solvents; oil extraction; low-temperature; narrow-boiling-range
Article:
Oil extraction is a process of separating oil from oil-bearing materials, such as soybean, rapeseed, peanut, corn germ, and various special oils. It is an important step in the production of edible oil and feed protein. The most common method of oil extraction is solvent extraction, which uses organic solvents to dissolve the oil and separate it from the solid residue.
The choice of solvent is crucial for the efficiency and quality of oil extraction. The solvent should have a high solubility for oil, a low boiling point for easy recovery, a low toxicity for safety and environmental protection, and a low cost for economic feasibility. Among various solvents, hexane is the most widely used one in the oil industry, because it meets most of the requirements. However, hexane is not a single compound, but a mixture of different isomers of C6 alkanes, which have different boiling points and properties.
According to the article by the user, hexane solvents can be classified into seven types, based on their boiling points: cyclohexane (80.74°C), methylcyclopentane (71.81°C), n-hexane (68.74°C), 3-methylpentane (63.28°C), 2-methylpentane (60.27°C), 2,3-dimethylbutane (57.99°C), and 2,2-dimethylbutane (49.72°C). Among them, 3-methylpentane and 2-methylpentane have the closest boiling points to n-hexane, which is the main component of commercial hexane solvents. By mixing 3-methylpentane and 2-methylpentane in appropriate proportions, a narrow-boiling-range hexane solvent can be obtained, which has a boiling range of 61-63°C and a dry point about 5°C lower than n-hexane solvent. This hexane solvent can be used as a low-temperature oil extraction solvent, especially for soybean oil extraction.
The advantages of using hexane solvents over conventional solvents are manifold. First, hexane solvents can reduce the solvent consumption and energy consumption, because they have a narrower boiling range and a lower dry point, which means less solvent is needed to dissolve the same amount of oil, and less heat is needed to recover the solvent from the oil. According to the article, the solvent consumption can be reduced from 1.2-2.0 kg/ton to 0.5-1.2 kg/ton by using narrow-boiling-range solvents. Second, hexane solvents can improve the quality and yield of oil and meal, because they have a lower temperature and a higher selectivity, which means less damage to the oil and protein, and less impurities in the oil and meal. According to the article, the oil yield can be increased by 0.5-1.0%, and the protein content of the meal can be increased by 0.5-1.5% by using low-temperature solvents. Third, hexane solvents can protect the environment and enhance the safety, because they have a lower toxicity and a lower volatility, which means less pollution to the air, water, and soil, and less risk of fire and explosion. According to the article, the hexane solvents belong to C6 alkanes, which are in accordance with the national standards of food additives, plant oil extraction solvents, and industrial hexane, and do not pose any regulatory problems.
The article also provides some examples of the industrial applications of hexane solvents, such as the extraction of soybean, rapeseed, peanut, corn germ, and other bulk oils, as well as the extraction of microbial oils, fish oils, and other heat-sensitive special oils. It claims that some domestic enterprises have developed and applied hexane solvents in dozens of oil extraction plants, and achieved remarkable results in terms of energy saving, quality improvement, environmental protection, and safety enhancement. It also suggests that hexane solvents have the potential to replace the No. 6 solvent and commercial n-hexane as the new choice for oil extraction.
In conclusion, hexane solvents are a family of C6 alkanes that can be mixed to form narrow-boiling-range solvents that are suitable for low-temperature oil extraction. They have many advantages over conventional solvents, such as energy saving, quality improvement, environmental protection, and safety enhancement. They also comply with the national standards and do not require any modification of the existing oil extraction equipment. They can be widely used in the production of various oils, especially soybean oil, and have a bright prospect in the oil industry.