Constituent Specific Heats

For each major constituent in the flue gas, calculate specific heat at both initial and final temperature using empirical correlations. The average specific heat over the temperature range is used for enthalpy calculations. See Gas Constants for the specific heat formulas and coefficients.

Oxygen

\begin{equation}\label{eq:gas-flue-gas-material-cp-o2-cpp} Cp_{O_2}(T) = 11.515 - \frac{172.0}{\sqrt{T}} + \frac{1530.0}{T}\end{equation}

Nitrogen

\begin{equation}\label{eq:gas-flue-gas-material-cp-n2-cpp} Cp_{N_2}(T) = 9.47 - \frac{3470.0}{T} + \frac{1.07 \times 10^6}{T^2}\end{equation}

Water Vapor

\begin{equation}\label{eq:gas-flue-gas-material-cp-h2o-cpp} Cp_{H_2O}(T) = 19.86 - \frac{597.0}{\sqrt{T}} + \frac{7500.0}{T}\end{equation}

Carbon Dioxide

\begin{equation}\label{eq:gas-flue-gas-material-cp-co2-cpp} Cp_{CO_2}(T) = \frac{16.2 - \frac{6530.0}{T} + \frac{1.41 \times 10^6}{T^2}}{44.0}\end{equation}

Average Specific Heat

\begin{equation}\label{eq:gas-flue-gas-avg-cp} \overline{Cp} = \frac{Cp(T_{initial}) + Cp(T_{final})}{2}\end{equation}

Symbols

\(Cp_{i}(T)\)	Specific heat of constituent i at temperature T \([\unit{ \btu\per\pound\degreeFahrenheit}]\)
\(T\)	Absolute temperature \([\unit{ \degreeRankine}]\)
\(T_{initial}\)	Initial absolute temperature \([\unit{ \degreeRankine}]\)
\(T_{final}\)	Final absolute temperature \([\unit{ \degreeRankine}]\)
\(\overline{Cp}\)	Average specific heat over temperature range \([\unit{ \btu\per\pound\degreeFahrenheit}]\)