馏分liúfèn分馏石油、煤焦油等液体时,在一定温度范围内蒸馏出来的成分。分馏石油,温度在50—200℃之间的馏分是汽油,温度在200—310℃之间的馏分是煤油。{fraction; a part separated when petroleum, coal tar or other liquid is distilled within a given range of temperature: gasoline in the range of 50-200℃ and kerosene in the range of 200-310℃}