The development of a web-based software toolbox is proposed to enable predictions of product yields and product composition in thermal biomass- conversion processes. Biomass pyrolysis is the main focus because of its commercial importance, and because it is the first step in all thermal-conversion processes (gasification, combustion, etc.). Several kinetic models will be incorporated in the software, including the model developed by the proposer, so that the user can choose what best fits the needs. Software development will utilize an extensive database of hundreds of biomass experiments performed over two decades of research. For each of the ~50 biomass feedstocks, time-resolved product evolutions were measured (~16 volatile species, including bio-oil) at three heating rates. This database, plus the experience in kinetic analysis and software development, puts the proposing firm in a unique position for the proposed effort, also providing a strong competitive advantage. The overall objective of the proposed project is to develop a comprehensive, web-based software tool for modeling thermal conversion of biomass. The Phase I project objective is to develop a software toolbox that incorporates five commonly used kinetic models, a database of ~50 biomass types, and the ability to account for biomass particle size variation. The Phase II objectives are: to expand the number of models included in the toolbox; to expand the existing experimental database to include additional types of biomass; to create an interpolation scheme that allows the user to model the behavior of unknown biomass on the basis of its composition; and to integrate the toolbox with Computational Fluid Dynamics (CFD) codes. The following Phase I tasks are envisaged: (1) kinetic analysis of experimental data; (2) code development; and (3) testing, validation, and product evaluation. Commercial applications include: (1) design of biomass-conversion processes/facilities (biorefineries, pyrolyzers, gasifiers, combustors, etc.); (2) predicting outcomes of feedstock switching and changes in operating conditions; (3) research on biomass conversion; (4) Computational Fluid Dynamics (CFD) software packages; and (5) the capability to upload one's own data and have the proposed software toolbox develop a kinetic model and perform simulations.