For wood or coal pyrolysis, a Gibb's reactor can be used to predict the stable forms/products that will come out of the reactor. The coal/wood would probably have to be created as a combustion solid or as a pseudo-component with appropriate physical properties. If you already know the products, you can create user components for all reactants/products (as needed) and set up an Equilibrium Reactor or Stoichiometric Reactor with the reaction equation. If you have kinetic data, you can set up a Kinetic Reactor.

Do note, stable forms predicted by the Gibb's reactor means "most stable energy form, based on the information provided for the chemicals."

It also is important to note that "most stable energy form" is not what necessarily happens in the real world as this infers perfect catalysis for all reactions.
For example, CO2 is the most stable combustion product, but due to mechanistic effects CO is what is generally produced.