MEASUR-Tools-Suite v1.0.11
The MEASUR Tools Suite is a collection of industrial efficiency calculations written in C++ and with bindings for compilation to WebAssembly.
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Gas Composition

Detailed Description

The following documentation describes the formulas and algorithms used by the GasComposition class to compute gas mixture properties, combustion air requirements, and flue gas analysis. Each member function is documented with its formula and symbol table.

Specific Gravity Formula


Calculates the specific gravity of the gas mixture.

\begin{equation}\label{eq:gas-composition-set-specific-gravity-cpp} SG = \frac{\sum_{i} MW_{i} \cdot x_{i}}{22.4 \cdot 1.205}\end{equation}

\(SG\)Specific gravity of mixture \([\unit{ \unitless}]\)
\(MW_{i}\)Molecular weight of constituent i \([\unit{ \gram\per\mole}]\)
\(x_{i}\)Volume fraction of constituent i \([\unit{ \unitless}]\)

Stoichometric Air Formula


Calculates the stoichiometric air required for combustion.

\begin{equation}\label{eq:o2-required-air-cpp} O_{2,req} = \sum_{i} O_{2,gen,i} \cdot x_{i} \qquad\end{equation}

\begin{equation}\label{eq:gas-composition-set-stoichometric-air-cpp} Air_{stoich} = O_{2,req} \cdot \left(1 + \frac{1 - k_{O_2}}{k_{O_2}}\right)\end{equation}

\(O_{2,req}\)Oxygen required for combustion \([\unit{ \pound}]\)
\(O_{2,gen,i}\)Oxygen generated per constituent i \([\unit{ \pound}]\)
\(x_{i}\)Volume fraction of constituent i \([\unit{ \unitless}]\)
\(k_{O_2}\)Volume fraction of O_2 in dry air \([\unit{ \unitless}]\)
\(Air_{stoich}\)Stoichiometric air required \([\unit{ \pound}]\)

Estimate Excess Air From O2 Formula


Empirical formula to estimate excess air from flue gas O2 percentage.

\begin{equation}\label{eq:gas-composition-estimate-excess-air-from-o2-cpp} EA = \frac{8.52381 \cdot O_2}{2 - (9.52381 \cdot O_2)}\end{equation}

\(EA\)Excess air fraction \([\unit{ \unitless}]\)
\(O_2\)Flue gas oxygen percentage \([\unit{ \unitless}]\)

Calculate Enthalpy At Saturation Formula


Calculates enthalpy at saturation for water vapor.

\begin{equation}\label{eq:gas-composition-calculate-enthalpy-at-saturation-cpp} h_{sat} = 1096.7 \cdot (p_{H_2O} \cdot 29.926)^{0.013}\end{equation}

\(h_{sat}\)Enthalpy at saturation \([\unit{ \btu\per\pound}]\)
\(p_{H_2O}\)Partial pressure of water vapor \([\unit{ \atm}]\)

Calculate Saturation Temperature Formula


Calculates saturation temperature for water vapor.

\begin{equation}\label{eq:gas-composition-calculate-saturation-temperature-cpp} T_{sat} = 36.009 \cdot \ln(p_{H_2O} \cdot 29.926) + 81.054\end{equation}

\(T_{sat}\)Saturation temperature \([\unit{ \degreeFahrenheit}]\)
\(p_{H_2O}\)Partial pressure of water vapor \([\unit{ \atm}]\)

Total Composition Weight Formula


Calculates the total composition weight and sets the weight fraction for each constituent.

\begin{equation}\label{eq:gas-composition-set-total-composition-weight-cpp} W_{total} = \sum_{i} W_{i} \qquad \end{equation}

\begin{equation}\label{eq:gas-composition-weight-fraction} f_{i} = \frac{W_{i}}{W_{total}}\end{equation}

\(W_{total}\)Total composition weight \([\unit{ \pound}]\)
\(W_{i}\)Weight of constituent i \([\unit{ \pound}]\)
\(f_{i}\)Weight fraction of constituent i \([\unit{ \unitless}]\)

Heating Value Formula


Calculates the heating value of the mixture by summing weighted constituent heating values.

\begin{equation}\label{eq:gas-composition-set-heating-value-cpp} HV = \sum_{i} HV_{i} \cdot f_{i}\end{equation}

\(HV\)Heating value of mixture \([\unit{ \btu\per\pound}]\)
\(HV_{i}\)Heating value of constituent i \([\unit{ \btu\per\pound}]\)
\(f_{i}\)Weight fraction of constituent i \([\unit{ \unitless}]\)

Heating Value Volume Formula


Calculates the volumetric heating value of the mixture.

\begin{equation}\label{eq:gas-composition-set-heating-value-volume-cpp} HV_{vol} = \sum_{i} HV_{vol,i} \cdot x_{i}\end{equation}

\(HV_{vol}\)Volumetric heating value of mixture \([\unit{ \btu\per\cubicFoot}]\)
\(HV_{vol,i}\)Volumetric heating value of constituent i \([\unit{ \btu\per\cubicFoot}]\)
\(x_{i}\)Volume fraction of constituent i \([\unit{ \unitless}]\)

Modules

 Total Composition Weight Formula
 Calculates the total composition weight and sets the weight fraction for each constituent.
 
 Heating Value Formula
 Calculates the heating value of the mixture by summing weighted constituent heating values.
 
 Heating Value Volume Formula
 Calculates the volumetric heating value of the mixture.
 
 Specific Gravity Formula
 Calculates the specific gravity of the gas mixture.
 
 Stoichometric Air Formula
 Calculates the stoichiometric air required for combustion.
 
 O2 Percentage From Excess Air Formula
 Calculates flue gas O2 percentage from excess air.
 
 Estimate Excess Air From O2 Formula
 Empirical formula to estimate excess air from flue gas O2 percentage.
 
 Calculate Enthalpy At Saturation Formula
 Calculates enthalpy at saturation for water vapor.
 
 Calculate Saturation Temperature Formula
 Calculates saturation temperature for water vapor.
 
 Adjusted Flue Gas O2 For Calc Error Formula
 Iteratively adjusts calculated flue gas O2 to minimize error with target excess air.
 
 Get Mass Flue Gas Components Formula
 Calculates mass of flue gas components for a given excess air.
 

Files

file  gas_composition.h
 

Namespaces

namespace  gas_composition
 Contains functions for gas composition calculations.
 

Classes

class  gas_composition::GasComposition
 Represents a fuel gas mixture and its properties for process heat calculations. More...