Example 7.6

Starting from pyrite, plot the equilibrium curve for various pressures (0.8 atm, 1 atm, 1.2 atm) and initial concentrations of SO_{2} to the converter (6%, 8%, 10%).

Solution

Consider the reaction stoichiometry and the equilibrium constant for the oxidation of SO_{2}:

$\begin{array}{l}{\mathrm{SO}}_{2}+\frac{1}{2}{\mathrm{O}}_{2}\iff {\mathrm{SO}}_{3}\hfill \\ {K}_{\mathrm{p}}=\frac{{P}_{{\mathrm{SO}}_{3}}}{{P}_{{\mathrm{SO}}_{2}}\xb7{P}_{{\mathrm{O}}_{2}}^{0.5}}\hfill \\ {\mathrm{log}}_{10}({K}_{\mathrm{p}})=\frac{4956}{T}-4.678\hfill \end{array}$

Assume 1 kmol of dry air. The mass balances for the pyrite roasting and the sulfur dioxide conversion are as follows (Table ...