Partial hydrogenation effect of moisture contents on the combustion oils from biomass pyrolysis

In this work, the effects of initial moisture contents on combustion heats of oily products and the yields of oily products from conventional pyrolysis of spruce wood, hazelnut shell, and wheat straw were studied. The yields of liquid products increase with increasing pyrolysis temperature from 575 to 700 K and then decrease with increasing of the temperature. The yield of oil and higher heating value of the oil increases with increase of the initial moisture content of the sample. The highest liquid yield from spruce wood pyrolysis, 40.0% dry feed basis, was found for initial moisture content 60.5% and reactor temperature 700 K, the condition that also gave the lowest viscosity. The results indicated that the presence of moisture significantly influenced the thermal degradation rate of biomass pyrolysis. The HHVs from spruce wood, hazelnut shell, and wheat straw samples with highest moisture were 36.2, 33.0, and 31.3 MJ/kg, respectively. The HHVs from spruce wood, hazelnut shell, and wheat straw samples were 13.5, 11.1, and 11.0%, relatively higher than those of dry samples, respectively. The higher initial moisture content in the biomass sample may be caused by the intermolecular hydrogen transfer and further partial hydrogenation.