Hi,
Cantera is a little bit different from other software that do a similar job. In particular, Cantera has ideas of objects, so the equilibrate function does not return any results. Instead, the results are stored in the object which called the equilibrate function. For instance, if you set the problem up like this (in Python):
gas = ct.Solution('gri30.yaml')
gas.set_equivalence_ratio(1.0, 'CH4', 'O2:1,N2:3.76')
gas.equilibrate('HP')
then the state of the "gas" object will be set to the equilibrium state, and you can use all the methods of the Solution object to retrieve the results. In particular,
gas.X
gives you an array of mole fractions of the species.
Best,
Bryan