Fuel Oil Combustion Values

Overview

Engineering reference data for Fuel Oil Combustion Values in combustion engineering.

Key Formulas

Heat Release

$Q = \dot{m} \cdot HV$

Fuel energy release rate.

Air-Fuel Ratio

$AF = \frac{m_{air}}{m_{fuel}}$

Mass of air per mass of fuel.

Excess Air

$EA = \frac{O_2}{21 - O_2} \times 100\%$

From flue gas oxygen measurement.

Variables

Symbol	Description	Unit
$Q$	Heat release rate	W
$\dot{m}$	Mass flow rate	kg/s
$HV$	Heating value	J/kg
$AF$	Air-fuel ratio	—

Fuel Oil Heating Values

Characteristics of Fuel Oil Grades

The heat or combustion value of a fuel oil is expressed as the quantity of heat (Btu per gallon) released during combustion, where oxygen from the air reacts with hydrogen and carbon in the fuel.

Fuel oil grades 1 and 2 are commonly used for residential heating. Grade 2 is slightly more expensive but provides more heat per gallon. Grade 1 is used in vaporizing pot-type burners, while Grade 2 is used in atomizing gun-type and rotary fuel oil burners.

For heavier grades of fuel oil, proper atomizing temperature is critical. If the temperature is too low, the oil will not atomize and evaporate, leading to inefficient burner operation.

Note: $1 \text{ Btu/US gal} = 278.7 \text{ J/liter}$

References

• Original Source