Kinetic Modeling of Syngas Production From Bio-Oil Gasification

Gasification of bio-oil is a desirable process to produce syngas as a renewable resource with no net greenhouse gas emissions. Bio-oil is a mixture of hundreds of chemicals derived from fast pyrolysis of biomass. Production of syngas from bio-oil is usually a high pressure (26 bar) and high temperature (1220 – 1600 ˚C) process. Optimizing the process conditions (temperature, pressure, residence time, etc.) requires an improved understanding of the chemical kinetics of the thermal cracking reactions involved in bio-oil gasification.

We present a detailed kinetic model for bio-oil gasification, generated using Reaction Mechanism Generator (RMG), an open source software project that can build detailed kinetic models for hydrocarbon pyrolysis and combustion. Starting with a surrogate bio-oil consisting of ten known species, and reaction conditions (temperature, pressure, reaction time) from the literature, RMG predicts a kinetic model consisting of many thousands of elementary reactions between hundreds of intermediate species. Wherever possible, RMG uses databases of known values to find thermochemical and kinetic data, but usually they are unknown and it predicts parameters using group additivity methods and correlations.

We describe the challenges involved in using RMG to build a comprehensive model for surrogate fuels containing many large compounds, and how they can be overcome. Finally, we compare the results of the reaction modeling with experimental data on the composition of the syngas produced, and use the model to suggest optimal operating condition for bio-oil gasification.