\documentclass{article}
% translate with >> pdflatex -shell-escape <file>

% This file is an extract of the PGFPLOTS manual, copyright by Christian Feuersaenger.
% 
% Feel free to use it as long as you cite the pgfplots manual properly.
%
% See
%   http://pgfplots.sourceforge.net/pgfplots.pdf
% for the complete manual.
%
% Any required input files (for <plot table> or <plot file> or the table package) can be downloaded
% at
% http://www.ctan.org/tex-archive/graphics/pgf/contrib/pgfplots/doc/latex/
% and
% http://www.ctan.org/tex-archive/graphics/pgf/contrib/pgfplots/doc/latex/plotdata/

\usepackage{pgfplots}
\pgfplotsset{compat=newest}

\pagestyle{empty}

\usepgfplotslibrary{ternary}

\begin{document}
\begin{tikzpicture}
\begin{ternaryaxis}[
	xlabel=x (IPA),
	ylabel=y (water),
	zlabel=z (propene),
	axis on top,
]
% plotdata/ternary_data.txt is a table of the form
%A_propene A_water A_IPA  B_propene B_water B_IPA
% 0.0009   0.9990  0      0.9333    0.0667  0
% 0.0009   0.9988  0.0002 0.9303    0.0665  0.0032
% 0.0011   0.9975  0.0013 0.9135    0.0673  0.0191
% 0.0013   0.9962  0.0024 0.8956    0.0693  0.0351
%...
	\addplot3[tieline,fill=blue!10]
	table [x=A_IPA,y=A_water,z=A_propene] 
		{plotdata/ternary_data.txt};
\end{ternaryaxis}
\end{tikzpicture}
\end{document}
