The authors have developed a model for coal devolatilization that incorporates the diversity of coal structure in such a way that the analytical data obtained from solid state NMR provides the initial input data. Using an experimentally determined kinetic rate parameters, it is possible to fit the gas, tar and char production of a lignite and high volatile bituminous coal. The authors have employed percolation theory to provide analytical expressions for the lattice statistics required in devolatilization modeling. The percolation theory allows one to avoid the more time consuming Monte Carlo technique with no loss of generality or important statistical features. Percolation theory analytically describes the size distribution of finite clusters of sites joined by intact bridges but isolated from all remaining sites by broken bridges. The theory specifies a critical bridge population, depending only on the site coordination number, above which infinite arrays will coexist with clusters of finite size. It is a simple matter to adapt the structural features of percolation theory to both the tar and gas obtained in coal pyrolysis. The infinite arrays of percolation theory are interpreted as the macroscopic lattice of unreacted coal and/or char while the relatively small tar molecules may be identifiedmore » with the fine clusters of percolation theory. The details of the model are discussed together with the results obtained in modeling devolatilization behavior of coals of various ranks.« less