Comparison of multi-component kinetic relations on bubbling fluidized-bed woody biomass fast pyrolysis reactor model performance

Modelling of the thermochemical conversion process of biomass has been widely studied in the past. However, only a handful of works have been devoted to modelling pyrolysis at the bubbling fluidized-bed reactor level. Often, the most significant shortfalls of these models lie within the implemented devolatilization schemes, especially when only simple single-component mechanisms without product specification are used. This work compares the performance of two multicomponent, multistep kinetic reaction schemes implemented into a fluidized-bed level reactor model of fast pyrolysis. The first kinetic scheme only provides information on the amount of char, bio-oil, and gas yields whereas the second model provides compositional specifications of the resulting bio-oil and gases. This article compares the totals yields of char, bio-oil and gas with experimental data from a 5 to 10 kg/h fluidized bed fast pyrolysis system using three distinct biomass feedstocks. The results show that the model without compositional specification gave better agreement with the specific experimental results compared, especially for the yield of gas and char. The model with compositional specification gave good predictions of some components in the bio-oil, such as water, but modifications were shown to improve model accuracy to better account for the competition between transglycosylation and fragmentation reactions of cellulose.