Combustion Process Efficiency

Overview

Engineering reference data for Combustion Process Efficiency 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

Furnace Performance Indices

Furnace performance is evaluated through several efficiency metrics:

Thermal Efficiency ($\mu_t$) represents the ratio of energy output to fuel energy input:

$\mu_t = 100 \frac{E_o}{E_i}$

where $E_o$ is the energy output and $E_i$ is the fuel energy input, both in watts (W) or BTU per hour (Btu/h).

Annual Fuel Utilization Efficiency (AFUE) accounts for seasonal variations by comparing annual heat delivery to annual fuel consumption:

$AFUE = 100 \frac{E_{ao}}{E_{ai}}$

where $E_{ao}$ is the annual energy output and $E_{ai}$ is the annual fuel energy input.

Steady-state Efficiency (SSE) measures efficiency under consistent operating conditions:

$SSE = 100 \frac{E_i - E_l}{E_i}$

where $E_l$ represents energy losses during operation.

Typical Combustion Process Efficiencies

Combustion device efficiencies vary significantly based on technology and design:

References

• Original Source