Diesel, a mixture of light petroleum products and complex hydrocarbons (about 10-22 carbon atoms), is used as a diesel fuel. It is mainly composed of diesel fraction produced by crude oil distillation, catalytic cracking, thermal cracking, hydrocracking and petroleum coking, and can also be produced by shale oil processing and coal liquefaction. It is divided into light diesel oil (boiling point range about 180~370℃) and heavy diesel oil (boiling point range about 350~410℃). Widely used in large vehicles, railway locomotives, ships. Calorific value is 42.7MJ/kg.