Fuel oil is a broad term for various liquid petroleum-based fuels used for heating, power generation, and industrial applications. These oils are derived from crude oil through a refining process, which separates different components based on their boiling points. Fuel oil is typically classified into different grades, ranging from light to heavy, based on its viscosity and use. Key Types of Fuel Oil: Light Fuel Oil (LFO): This is a thinner, less viscous fuel, used primarily in heating systems, commercial boilers, and some small engines. It is commonly known as No. 1 and No. 2 fuel oil. No. 1 is often used for kerosene-style heating, while No. 2 is the most common residential heating oil. Heavy Fuel Oil (HFO): Heavier and more viscous than light oils, this type is used in large industrial furnaces, power plants, and large marine vessels. No. 5 and No. 6 fuel oils are common examples. No. 6 is typically referred to as bunker oil and is the heaviest, used in ships and large industrial burners. Residual Fuel Oil: A byproduct of the distillation process, this type of oil has a high viscosity and is used in specialized industrial applications, especially where high heat and energy are required. Composition and Characteristics: Hydrocarbons: Composed mainly of long-chain hydrocarbons, fuel oils can have various additives for stability, combustion efficiency, and reducing emissions. Viscosity: The viscosity (thickness) of fuel oil increases as its grade becomes heavier, requiring higher temperatures for effective burning. Sulfur Content: Fuel oils often contain sulfur, which contributes to air pollution. This has led to regulations limiting sulfur emissions, particularly for ships (e.g., IMO 2020 regulations). Uses of Fuel Oil: Heating: Common in residential and commercial heating, especially in colder climates where natural gas might not be readily available. Power Generation: Large-scale fuel oil burning is common in power plants for electricity generation, especially in areas where cheaper or alternative energy sources are not available. Marine Industry: Ships and vessels often run on heavy fuel oils like bunker oil due to their energy density. Industrial Processes: Fuel oils are used in various manufacturing processes requiring high temperatures, such as cement kilns and steel mills.