Development of a Circulating Fluidized Bed Reactor Model for Biomass Fast Pyrolysis for Process Simulation

The goal of this work is to develop an engineering reactor model for future integration with process simulations in order to gain a better understanding of the impact of fluid dynamics, heat transfer and reaction kinetics on the products yields and composition. The current work addresses the issues of providing an engineering approximation of the effects of biomass composition variations, residence time and reaction temperature on pyrolysis process by incorporating the following features: (1) a flexible pyrolysis reaction mechanism inclusive of the catalytic effect of intrinsic contaminants, (2) one-dimensional, steady-state momentum balance for solids-gas flow, and (3) one-dimensional, steady-state energy equation. The developed model provides valuable information about the temperature distribution, velocity profiles and species concentration profiles along the rector at a low computational cost and it offers better product predictions compared to the yield reactor models used in TEAs.

This project was a collaborative work between the Department of Mechanical Engineering at Colorado School of Mines (CSM), the Bioenergy Analysis Team at the National Renewable Energy Laboratory (NREL), the Computational Pyrolysis Consortium (CPC), which is a collaboration among five U.S. Department of Energy (DOE) national laboratories: Oak Ridge National Laboratory (ORNL), the National Renewable Energy Laboratory (NREL), the Pacific Northwest National Laboratory (PNNL), Argonne National Laboratory (ANL), and Idaho National Laboratory (INL). The consortium provided results from detailed two and three dimensional CFD reactor models and detailed three dimensional single particle model for verification of the developed reactor model.

FUNDING: NREL

Publications

  1. Trendewicz, R. Braun, J. Ziegler, A. Dutta, “One dimensional Steady-State Circulating Fluidized-bed Reactor Model for Biomass Fast Pyrolysis”, Fuel, 133 (2014) 253-262.
  2. A. Trendewicz, R. Evans, A. Dutta, R. Sykes, D. Carpenter, R. Braun, “Evaluating the effect of potassium on cellulose pyrolysis reaction kinetics”, Biomass and Bioenergy, 74 (2015) 15-25