Process Heat Utilities

Detailed Description

This module provides reusable functions and helpers for process heating calculations, such as excess air, available heat, and other shared logic. These functions are used across multiple process heat calculators to ensure consistent calculations and reduce code duplication.

Excess Air Calculation

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Calculate excess air from oxygen concentration in flue gas.

The excess air is determined from the oxygen concentration in the flue gas using stoichiometric relationships. The calculation accounts for the fact that excess oxygen in flue gas indicates incomplete combustion air utilization. The formula uses empirical factors derived from combustion stoichiometry for typical fuels.

This calculation is a fundamental component used throughout process heat calculations, including:

• O2 enrichment analysis (O2 Enrichment Calculator)
• Solid/liquid flue gas material calculations (Solid/Liquid Flue Gas Material Calculator)

The formula provides a quick estimate of excess air based on measured flue gas oxygen content. For more complex fuel compositions, iterative refinement may be applied (as in solid_liquid_flue_gas_material::calculateExcessAirFromFlueGasO2).

\begin{equation}\label{eq:process-heat-excess-air} EA = \frac{8.52381 \cdot O_{2,flue}}{2 - 9.52381 \cdot O_{2,flue}}\end{equation}

Symbols

\(EA\)	Excess air \([\unit{ \unitless}]\)
\(O_{2,flue}\)	Oxygen in flue gas \([\unit{ \unitless}]\)
\(8.52381\)	Stoichiometric air factor \([\unit{ \unitless}]\)
\(9.52381\)	Oxygen flue gas factor \([\unit{ \unitless}]\)

Note

Input oxygen should be provided as a fraction (not percentage). For example, 3% O2 should be passed as 0.03.

See also

O2 Enrichment Calculator

Solid/Liquid Flue Gas Material Calculator

Modules
	Excess Air from Flue Gas O2
	Calculate excess air from oxygen concentration in flue gas.

Files
file	process_heat.h
	Utility section for common process heat functions.

Namespaces
namespace	o2_enrichment
	O2 enrichment calculations for fuel-fired furnaces.

Classes
struct	o2_enrichment::O2EnrichmentResults
	Results of the O2 enrichment calculation. More...

Functions
double	process_heat::calculateExcessAir (double o2_flue_gas)
	Calculates excess air from O2 in flue gas.

Function Documentation

calculateExcessAir()

double process_heat::calculateExcessAir

(

double

o2_flue_gas

)

Parameters

[in]

o2_flue_gas

O2 in flue gas (fraction)

Returns

Excess air (fraction)