Diesel oil is separated from crude oil by the petroleum refining process. The following is a simple diesel refining process:
1. Crude oil refining: Crude oil is a mixture that contains different types of hydrocarbons. First, the crude oil is heated through a distillation column. In the tower, the crude oil gradually breaks down at different temperatures, producing components with different boiling points.
2. Distillation: In the distillation tower, the crude oil is broken down into different fractions by controlling the temperature gradient. Diesel oil is a fraction in the temperature range of about 200-350 degrees Celsius.
3. Fractionation: Diesel oil is separated from other oil products such as gasoline, lubricating oil and heavy oil through the fractionation process. This process is based on the boiling points of the components at different temperatures, thus separating the diesel from the other components.
4. Desulfurization: Diesel may contain sulfur, so desulfurization is needed to reduce environmental pollution and engine life. Common desulfurization methods include catalytic desulfurization or thermal desulfurization.
5. Refining: Through further refining processes, such as deep hydrocracking, saturation, decolorization, etc., the quality and performance of diesel can be improved.
Finally, through the above steps, diesel oil is extracted and distributed to gas stations or industrial uses by means of transportation such as roads, ships and other transportation methods. The specific process of refining diesel oil may vary from refinery to refinery, but the overall steps are roughly the same.