This notebook contains course material from CBE20255 by Jeffrey Kantor (jeff at; the content is available on Github. The text is released under the CC-BY-NC-ND-4.0 license, and code is released under the MIT license.

Henry Law Constants

Henry's law provides a simple model for the partial pressure of gases dissolved in water. For a liquid phase mole fraction $x_i$, the corresponding partial pressure $p_i = y_i P$ is

\begin{equation} y_iP = H_i(T) x_i \end{equation}

where $H_i(T)$ denotes the Henry's law constant.

This notebook provides a calculator to estimate $H_i(T)$ using the correlations specified in IAPSW G7&-04 Guideline on the Henry's Constant and Vapor-Liquid Distribution Constant for Gases in $H_2O$ and $D_2O$ at High Temperatures.

Henry's Law Calculator

Run both of the following cells before using the calculator.

In [ ]:
!pip install -q iapws
In [11]:
#@title Henry's Law Constant in Various Units { run: "auto", vertical-output: true }
Gas = "CO2" #@param ["Ar", "CH4", "C2H6", "CO", "CO2", "H2", "H2S", "He", "Kr", "N2", "Ne", "O2", "SF6", "Xe"]
T = 25 #@param {type:"number"}

from iapws._iapws import _Henry as Henry

P_henry = Henry(T + 273.15, Gas, liquid="H2O")
print("Henry's Law Constant:")
print("    [MPa] =", round(P_henry,2))
print("    [bar] =", round(P_henry*10, 1))
print("    [atm] =", round(P_henry/0.101325, 1))
print("   [psia] =", round(P_henry*14.696/0.101325,0))
Henry's Law Constant:
    [MPa] = 165.64
    [bar] = 1656.4
    [atm] = 1634.8
   [psia] = 24025.0
In [ ]: