ThermoProp is a thermodynamic module developed specifically for Brilliant. The module is based on the thermodynamic software solution from HAUG Technology. By utilizing a generic programming interface, the equation solver layer in ThermoProp is entirely independent of which equation of state (EOS) is being used. Currently, we use a special purpose dry ice model for the solid, Peng-Robinson EOS for mixtures, and Span-Wagner EOS for pure CO2. Peng-Robinson is used for hydrocarbon components, of which there are more than 220 in the library. The water model is Saul-Wagner EOS.