What formula is used to calculate the Btu/lb heat content of fuel oil?

The formula used to calculate the Btu/lb heat content of fuel oil is based on its American Petroleum Institute (API) gravity, which is a measure of how heavy or light petroleum liquid is compared to water. The correct formula, which is represented as 17,687 + 57.7 X API at 60°F, provides a precise calculation of the heat content based on the specific gravity of the oil.

This formula indicates that as the API gravity increases, the heat content also increases, reflecting the fact that lighter oils typically contain more energy per unit weight than heavier oils. The constants in the formula (17,687 and 57.7) are derived from empirical data to ensure accuracy in estimating the Btu content of various types of fuel oils at a standard temperature of 60°F.

Therefore, this option is chosen because it combines a scientific basis with practical application, enabling operators to estimate the heat content of fuel oil accurately, which is essential for combustion efficiency and energy balance calculations in heating applications.