What is number 4 fuel oil?

No. 6 fuel oil (also known as heavy oil or industrial oil) is a highly viscous fuel primarily used in large combustion equipment in industrial applications, such as boilers, generator sets, and industrial furnaces. It provides high-temperature and high-pressure thermal energy for industrial processes, supporting critical operations including heating, steam generation, and power generation. Additionally, owing to its high combustibility and continuous energy supply capabilities, it is suitable for heavy-duty equipment scenarios requiring high-power output, such as marine propulsion systems and steel mills. Furthermore, hydrogenated No. 6 fuel oil (hydrotreated No. 6 fuel oil) can be extended to agricultural applications, including powering agricultural machinery, supplying energy for greenhouse cultivation, and serving as a power source for certain transportation vehicles. With its high calorific value and stable performance, it meets diverse industries' demands for efficient and reliable energy. During usage, safety protocols must be observed to prevent exposure to open flames, and proper ventilation measures should be implemented to mitigate harmful gas emissions. Compliance with relevant environmental and safety regulations is also essential during storage and handling to avoid soil and groundwater contamination.

No. 2 fuel oil is a distillate fuel oil, primarily suitable for household and small industrial burners. In domestic settings, it can be used in home heating equipment and small household combustion appliances; in industrial applications, it is suitable for small combustion devices such as heating equipment in small factories or compact industrial furnaces. The properties of this fuel oil allow it to meet the requirements of small combustion equipment, serving both daily household heating needs and small-scale industrial production demands.

In the local context, "grade 5 gasoline" likely refers to gasoline complying with the Euro 5 emission standard (a common possible mix-up in terminology), as there is no RON 5 grade available here. Euro 5 gasoline is defined by its low sulfur content (maximum 10 parts per million), significantly lower than the previous Euro 4 standard (50 ppm). This reduces harmful emissions like sulfur dioxide, particulate matter, and nitrogen oxides, benefiting the environment and public health. It is compatible with modern vehicles equipped with advanced emission control systems (e.g., catalytic converters, particulate filters) since high sulfur levels can damage these components over time. In Malaysia, Euro 5 gasoline is widely accessible at major petrol stations, offered in common octane ratings such as RON95 and RON97—both meeting Euro5 criteria. Using Euro5-compliant gasoline also helps maintain optimal performance of newer models and extends the lifespan of their emission control systems, aligning with the country’s efforts to improve air quality.

#4 Fuel oil is a type of heavy fuel oil, blended from residual oil in the petroleum refining process. It has high viscosity and usually needs to be heated to reduce viscosity for easier transportation and combustion. In Malaysia, it is primarily used in large industrial boilers and power generation equipment at power plants, providing stable thermal energy for industrial production and electricity supply. Additionally, owing to its high energy density and relatively economical cost, it is frequently employed as fuel for low-speed diesel engines in large vessels, aligning with Malaysia's shipping demands as a maritime transport hub. Furthermore, certain heavy industrial kilns (such as cement kilns and metallurgical kilns) along with power systems of heavy machinery also utilize #4 fuel oil. This fuel oil is well-suited for applications requiring sustained, high-volume thermal energy output, serving as a crucial supplement to industrial energy within the energy mix and supporting the stable operation of related industries. Proper storage and handling procedures must be strictly followed during usage to ensure safety and combustion efficiency.

Fuels are mainly divided into three types: solid, liquid, and gas. Solid fuels such as coal, wood, and biomass pellets have stable forms and are easy to store and transport. They are commonly used for power generation, industrial smelting, and household heating, but some types have high ash content after combustion. Liquid fuels include gasoline, diesel, and biodiesel, which have high energy density and are convenient to use. They are the core power source in the transportation field, widely used in internal combustion engines of automobiles and ships, as well as industrial boilers. Gaseous fuels such as natural gas, liquefied petroleum gas, and hydrogen have high combustion efficiency, low pollutant emissions, and good cleanliness. They are often used for household cooking, industrial heat treatment, and gas turbine power generation. Some gaseous fuels like compressed natural gas are also gradually being applied in the automotive field to reduce carbon emissions. These three types of fuels each have their important positions in the energy structure, and when choosing, multiple factors such as energy density, environmental friendliness, application scenarios, and cost need to be comprehensively considered.