Catalytic Hydropyrolysis of Beetle Killed Trees for the Production of Transportation Biofuels

We conducted catalytic hydropyrolysis of beetle‐killed trees: Pine, Ash tree, and Redbay in a micro‐pyrolyzer (Py/GC–MS) and investigated the performance of heterogeneous catalysts like HZSM‐5, NiMo‐HZSM‐5, and NiRe‐HZSM‐5. We also investigated the effects of temperature, catalyst‐to‐biomass ratio, and hydrogen pressure on product yield. Our findings reveal that aromatic yields increase with temperature and catalyst‐to‐biomass ratio but decline at higher hydrogen pressures; additionally, higher catalyst acidity enhances both total hydrocarbon production and selectivity toward C7–C8 aromatics, with each feedstock exhibiting distinct optimal conditions. The type of metal doped on the HZSM‐5 zeolite plays an important role in the process. Under the tested conditions (500°C, 21 bar, and catalyst‐to‐biomass ratio 10:1), Molybdenum (Mo) outperformed Rhenium (Re) for promoting alkane formation. The NiRe‐HZSM‐5 catalyst produced only a modest yield of alkanes (0.7 wt.%) compared to the higher yield (10.0 wt.%) observed with NiMo‐HZSM‐5. Overall, NiMo‐HZSM‐5 was the optimum catalyst for the production of alkanes. HZSM‐5 is the optimum catalyst for the production of aromatic hydrocarbons. To optimize the operating parameters and enhance aromatic yield, we employed a response surface methodology (RSM). The analysis revealed that the maximum product yield of 35.0% is obtained at 570°C, 14 bar, and catalyst‐to‐biomass ratio of 14:1. The highest aromatic yield of 28.3% is obtained at 562°C, 14 bar, and catalyst‐to‐biomass ratio of 13:1. The highest alkane yield is 5.7%, obtained at 400°C, 14 bar, and catalyst‐to‐biomass ratio of 8.6:1.