Equilibrium calculations offer a practical way to observe the effects of process variables, such as temperature and amounts of raw materials, on product composition.
Gem - Equilibrium Compositions Module
With this program option you can calculate the equilibrium composition and amounts of prevailing phases in any reactor. You only specify the raw material amounts, temperatures and the species of the system. These species can be specified by selecting the elements of the system, or typing the formulae, or by editing the old file. Activity coefficients can be given, if necessary, as constants or as functions of temperature and composition or instead of manually entering activity coefficient it is possible to use pre-defined activity models. This module also includes cell equilibrium calculations.
Calculations can be repeated at stepwise intervals over the range of raw material amounts or reaction temperatures in order to visualize the effect of these process variables. For example, you can observe the effect of temperature on arsenic evaporation from copper-iron sulfides, or the effect of chlorine feed on titanium chlorination.
Calculations are done using the Gibbs energy minimization method as soon as the user specifies the input data and presses the Calculate button. The results can be, for example, the equilibrium composition of the chemical system, which can be plotted as a function of temperature, partial pressure, etc.
You can select linear or logarithmic scale and set maximum and minimum values for the x- and y-axis.
The tabular numerical data which is used to draw the diagram can be saved as a normal text file by pressing the Table button. These files can be read, for example, in spreadsheet programs for further calculations.
A special Cell Equilibrium calculation option is also available for calculating the charge and composition of phases in electrochemical cells, such as batteries.