The mixture of oils of which it is composed must be separated out into a number of products such as petrol, aviation spirit, kerosene, diesel oils and lubricants, all of which have special purposes.

• 它包含的油类混合物必需分离成一系列产品，如汽油、航空汽油、煤油、柴油和润滑油，这些种类有不同的使用领域。