Lumped chemical kinetic modelling of raw and torrefied biomass under pressurized pyrolysis

Accurate prediction of the yield and composition pyrolysis products is an important requirement for design operation reactors gasifiers. In this paper, a new semi-global kinetic reaction scheme proposed to predict pyrolytic volatiles (classified as main chemical family groups), non-condensable gases char derived from both raw torrefied biomass wide range operating conditions. The model based on adjustable mechanistic scheme, which includes combination three different sub-mechanisms primary reference biopolymers (cellulose, hemicelluloses lignin) secondary their respective intermediates. extent primary/secondary reactions varied according process features (linear heating rate, temperature, time, volatile residence time pressure). in involve liquid-phase high molecular weight intermediates (producing gases, water vapour char) well homogeneous heterogeneous gas-phase conversion volatiles. predictions were validated using experimental data obtained fast micropyrolyzers (at 500–600 °C rates 27 110 °C/s, respectively) slow laboratory-scale high-pressure fixed bed reactor 400–600 °C, 7 °C/min 1, 15 30 bar). general, comparison outputs satisfactory, predicted accurate trends product distribution changes lignocellulosic (the pre-removal case biomass), rate pressure. correctly significant increase (14.6 wt%) when instead was pyrolyzed due significance char-forming during biomass. Moreover, model’s reliability proven through its various condensate groups bio-oil produced micropyrolyzer (maximum deviation < 4 wt%). Corresponding data, showed that effect pressure most 1–15 bar (bio-oil decreased by 5.4 wt%), whereas no evident 15–30 bar. CO2 CO yields slightly under-predicted around 3 wt%, attributed catalytic effects inherent inorganics cracking not considered scheme. Future work should focus validation at temperatures below 400 °C.