Intellectual merit of the proposed activity: Distributed fast pyrolysis units located close to biomass resources could convert between 60 and 75 % of lignocellulosic materials into crude bio-oils of which 40 % could be further transformed into transportation fuels via hydrotreatment in rural or centralized bio-oil refineries. In spite the importance of these reactors, the available knowledge on kinetics and transport phenomena in lignocellulosic materials has not been properly integrated for the design of pyrolysis reactors. The mechanism of lignin pyrolysis reactions responsible for the production of precursors of transportation fuels (mono phenols and lignin oligomers) also remains poorly studied. This proposal will advance the understanding of lignin pyrolysis reactions and the associated transport phenomena to support the development of multi-scale mathematical models for the design of selective pyrolysis reactors and take advantage of the problems associated with the design of these reactors to developed multidisciplinary team working skills in K-12, undergraduate and graduate students.
The research component involves integrated experimental and simulation tasks that will allow for the identification of conditions maximizing the production of precursors of transportation fuels from the pyrolysis of lignocellulosic materials. The approach proposed to design selective Auger pyrolysis reactors requires a detailed understanding of the kinetics of primary and secondary reactions, the evaporation and cracking of liquid intermediates, heat and mass transfer at the cell level, particle size and solid residence time distribution and a model to describe the behavior of single biomass particles.
The proposed project will advance the understanding of lignin depolymerization reactions stressing on the role of lignin liquid intermediates as precursors for the production of lignin oligomers. A multi-scale mathematical model will be developed to design selective Auger pyrolysis reactors. For the first time this model will integrate (1) new kinetic models for lignin pyrolysis, (2) a model to describe the effect of the evolving biomass cell structures on the effective axial and radial thermal conductivity and mass diffusivity and (3) a single particle model that takes into account axial and radial heat and mass transfer and secondary reactions to identify the conditions which maximize the production of precursors of transportation fuels.
Broader impact: The kinetic parameters of lignin pyrolysis that will result from this project, in conjunction with kinetic information reported in the literature, will support the development of multi-scale models to design and evaluate more selective pyrolysis reactors. This contribution is significant because the expected gains in the production of precursors of transportation fuels from lignocellulosic materials could significantly increase the production of bio-fuels and reduce the nation's dependency on imported oil. The development of a systematic methodology to design pyrolysis reactors will be a significant contribution to future research on the design of other thermochemical reactors such as gasification and torrefaction reactors. Thus, the outcome of this project is not only expected to fundamentally advance the field of biomass thermo-chemical conversion but also have broad and highly positive societal impacts.
An educational plan to develop multidisciplinary team working skills in K-12, undergraduate and graduate students working in the development of selective pyrolysis reactors will be implemented and assessed. Thus the educational component of this proposal will also have a wide reaching impact because it will be conducted in such a way that will contribute to the teaching of K-12, undergraduate and graduate students to work in multidisciplinary teams while developing teaching modules, experimental set-ups and designs of selective pyrolysis reactors.
