A generalized method was developed to implement complex chemistry from third-party computational coal chemistry tools within multiphase, reacting computational fluid dynamic (CFD) codes. This method involves generating response surfaces that represent the computational coal chemistry tool output and using them to build a comprehensive surrogate model which can be easily incorporated into a CFD code. In this first part of a series of work, the method was applied to coal pyrolysis of Powder River Basin coal using PC Coal Lab (PCCL) and Carbonaceous Chemistry for Computational Modeling (C3M) to generate the series of response surfaces which form the basis of the surrogate model that can be implemented in CFD. This method has the benefit that local environmental variables (such as heating rate, final pyrolysis temperature, local pressure, and particle diameter) can be incorporated as part of the chemistry model in CFD on a cell by cell, time step by time step basis which creates the potential to significantly increase the accuracy of and reduce uncertainty in modeling coal chemistry within CFD. As demonstrated with this surrogate modeling method, the modeler is alleviated of the responsibility to predetermine a heating rate and reactor temperature for pyrolysis. This particular part of the work focuses on the theory and development of the surrogate model method. The methods used to generate the response surfaces, build them into a coherent surrogate model, and estimate the thermochemical properties of pseudocomponents are discussed. Future work and publication will focus on verification within CFD, validation against experimental data, multidimensional surrogate model development, and application of the surrogate model methodology to other reaction chemistry.