Development of a generalized numerical framework for simulating biomass fast pyrolysis in fluidized-bed reactors

• A multi-fluid model is coupled with a global kinetics mechanism in this simulation.
• The present model is able to predict the product yield of a fast pyrolysis reactor.
• The tar yield will increase if the biomass injector location is elevated.
• Increasing the superficial velocity of the feeding nitrogen also increase the tar yield.
• An object-oriented, open-source code is available.

A numerical framework for simulating biomass fast pyrolysis is developed in this study. Fast pyrolysis, a thermochemical conversion process converting low-value lingo-cellulosic biomass to various useful products has gained increased interest. This study is to develop an open-source computational tool to help understand the complex phenomena involved within the biomass fast pyrolysis process. In this framework, a multi-fluid model is applied to simulate the multi-phase hydrodynamics while global reaction kinetics is used to describe the physicochemical conversion. The coupling of these two methodologies is realized by a time-splitting method. The model results are validated using experimental data from fast pyrolysis reactors. Good levels of agreement are obtained in the product distribution including tar, biochar, and syngas. The parametric study also indicates that the tar yield can be increased if the biomass injector location is elevated or the superficial velocity of the feeding nitrogen is increased. One feature of the present numerical framework is that sub-models for different constitutive hydrodynamic relations and chemical reactions can be readily incorporated into this framework owing to the object-oriented feature of the baseline code.