I have been trying to simulate a downdraft gasifier, and I happen to have both the ultimate and proximate analysis of the chosen biomass sample BUT I'm having some difficulties in the simulation side. I have tried to solve this problem using Gibbs energy minimization technique incorporated with Newton-Raphson Method with the help of MATLAB but unfortunately the code is saying error. So, if it is possible, I humbly request a help on how to do it in EES or a hint on how to do it on Excel, or on any other software.