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Catalytic pyrolysis of pine wood was carried out using H + ZSM-5 in a hydrogen environment. The first objective of this study was to investigate the effect of hydrogen pressure on catalytic pyrolysis using H + ZSM-5. The study found that there was no increase in the aromatic hydrocarbons as the hydrogen pressure increased. The second objective of this study was to incorporate a hydrogenation effect in addition to catalytic-cracking during pyrolysis so that the amount of hydrocarbons in the bio-oil could be increased. The effect of hydrogen pressure on the Mo-impregnated catalyst was investigated in pine wood pyrolysis. The Mo/ZSM-5 catalyst was not as active as H + ZSM-5 in lower pressures (100−300 psi); however, at 400 psi, Mo/ ZSM-5 gave more hydrocarbons than H + ZSM-5 did. A significant increase in aromatic hydrocarbons was found when the H + ZSM-5 catalysts were impregnated with metals (Ni, Co, Mo, and Pt) as compared to just the zeolite at 400 psi. On average, 42.5 wt.% of biomass carbon was converted into hydrocarbons. Aromatic selectivity of major hydrocarbons was almost the same during hydrocatalytic pyrolysis of pine wood at 400 psi in the presence of all metal-impregnated H + ZSM-5 catalysts.

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A fast pyrolysis process has emerged as one of the techniques to produce transportation fuels using various biomass types that are regionally important. It is well understood that high heating rates, very small particles with low mass transfer limitations, and moderate operating temperatures are essential for obtaining high yield of liquid from the fast pyrolysis process. However, how the heating rates and operating temperatures would influence individual compounds in the liquid obtained from the fast pyrolysis process has not been studied in detail. Therefore, a microscale pyrolysis study was performed by changing different parameters (biomass type, filament heating rate, and final pyrolysis temperature) to understand the influence of these operating parameters on each compound formed during the process. Two biomass types (pine wood and switchgrass) were selected for this study: (i) pine wood was selected because of its availability in the southeastern region of the United States, and (ii) switchgrass was chosen because it has been identified as one of the bioenergy crops in the United States. Pyrolysis temperatures were changed from 450 to 750°C in increments of 50°C, whereas the heating rates selected were 50, 100, 500, 1000, and 2000°C/s. Twenty-eight biooil compounds were quantified in each experimental condition. This study found that phenols and toluene concentrations increased with the increase in pyrolysis temperature irrespective to the biomass type. On the other hand, the change in the yield of ketones, furans, and guaiacols with the change in pyrolysis temperature depended on the type of biomass. The effect of filament heating rate on bio-oil yield was not statistically significant because the biomass heating rate was almost constant irrespective of different filament heating rates.

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