Light fuel oil is an oil product with a low boiling point (usually below 200°C), low density (e.g., naphtha at 0.65-0.75 g/cm³), low viscosity, good fluidity, and high volatility. It primarily consists of low-molecular-weight hydrocarbons (5-12 carbon atoms) and has low impurity content (e.g., low sulfur). Common types include gasoline, diesel, kerosene, and naphtha. Gasoline is mainly used in automobile internal combustion engines, diesel is suitable for truck and bus diesel engines, while naphtha serves as an important chemical feedstock for producing ethylene, fertilizers, or blended gasoline products.
Heavy fuel oil is the residual heavy oil remaining after light oil extraction from crude oil. It has a high boiling point (typically above 200°C, sometimes exceeding 350°C), high density (0.82-0.95 g/cm³), high viscosity, poor fluidity, and low volatility. Composed mainly of high-molecular-weight hydrocarbons (over 20 carbon atoms), it contains more impurities such as sulfur. Common types include residual oil and fuel oil, primarily used in power plant boilers, industrial furnaces, and marine medium/low-speed engines. Some high-viscosity heavy oils require preheating to improve fluidity before use.
Regarding processing, crude oil undergoes distillation to separate light oil first, with heavy oil further processed through methods like catalytic cracking to extract additional light oil products. Environmentally, light oil combustion generates fewer pollutants, whereas heavy oil combustion produces relatively higher emissions. However, environmentally compliant products like low-sulfur heavy oil are now available.
