Fractional distillation of bio-oil derived from pyrolysis of corn stover was investigated under atmospheric
and reduced pressure/vacuum conditions. Characterization of the fractions in terms of moisture, total
acid number (TAN), energy content, elemental and chemical compositions was performed to evaluate
the effectiveness of the distillation process in separating the components and rendering improved
product properties. Results showed high yields (wt.%) of the heavy fractions (b.p. 180–250 C at 1 bar;
160–230 C at 0.5 bar) and significant reduction in moisture and TAN content. Water was obtained as
a separate layer in the first (light) fraction (b.p.6100 C at 1 bar; 680 C at 0.5 bar). The heating values
increased, especially for the light distillates in both atmospheric and vacuum distillation and the heavy
distillates in atmospheric distillation. Analysis of the chemical composition showed that aromatic and
oxygenated compounds were distributed in the light and middle fractions (15–20%) while phenolic
compounds were concentrated in the heavy fraction (53%). The distillation process was effective in
separating the components and yielding a product (heavy fraction) with improved properties and composition
and which can be further utilized as feedstock for future upgrading procedures or as a blending
material with other liquid fuels.