Dimensional Analysis of Auger-Type Fast Pyrolysis Reactors

Modeling of fast pyrolysis reactors is challenging, even with state of the art computational tools and design, because rules to scale up well-running fast pyrolysis reactors are missing. Dimensional analysis is a classical tool to evaluate complex processes on a scientific basis and its application to fast pyrolysis is presented herein. Using the example of auger-type fast pyrolysis reactors, it is shown that scale-up can be reduced to a set of simple design rules. Full similarity of reaction conditions can never be achieved for fast pyrolysis in general, but it is shown which similarities are affected and to which extent they change. Dimensionless numbers derived from this analysis can even be used to describe the influence of parameters on the reactor performance; however, a significant reduction in complexity is required to achieve a practical relevance list. Strategies are outlined to achieve such a reduction based on partial similarities of rate-determining steps.