I first solved the non-ideal Gibbs problem (constrained free energy minimization with fugacity coefficients below unity; i.e., not ideal gases) in February of 1986. I didn't publish the results until December of 1991, which demonstrated the efficacy of the formulation. I didn't reveal the mathematics at that time because the deadline for submittal was approaching and the paper length was limited. I finally published the underlying mathematics in 2019. I wrote the code while stranded in Chicago's O'Hare Airport during that blizzard over 35 years ago. It is now a Windows application. Not only does it run interactively, but you can also drop a reaction file and property database onto the executable and it will run in batch mode, as shown in the attached figure. This means that you can feed it reactions from another program, adjusting parameters (moles, pressure, temperature) based on results in order to lock in on a condition of particular interest. I have posted the publications on RG and the software can be downloaded with no strings attached.