The economic analysis performed has the purpose of determining the conditions under which the decentralized conversion of
biomass to bio-oil via fast pyrolysis can actually reduce total fuel
acquisition costs for a central gasification/bio-refinery plant. For
the purpose of the analysis a circular area S of radius Rn-source of
homogenously distributed biomass (i.e. energy crops) of surface
density (dry t/ha) δ and a central plant C are considered (see
Fig.1). The direct distance between the center of the circular area P
and the central plant C is equal to D. The investigation is based on
the comparison of two different scenarios: In the first one, the
biomass of each internal point (field) of the circular surface S is
directly transported to the central plant C. In this case, the total
fuel acquisition cost equals to the sum of the purchase plus the
road transportation cost of the biomass. In the second scenario,
the biomass inside S is firstly transported from every local field to
P, where it is converted to bio-oil in a fast pyrolysis unit. The
produced bio-oil is afterwards transported to C. The total fuel
acquisition cost of this scenario includes the cost of purchasing
and transporting the biomass to P, the cost of producing bio-oil in
the fast pyrolysis unit as well as the cost of transporting it to C. The
capacity of the biomass considered is a core parameter of the
evaluation, since it greatly influences the capital cost of the plant
and therefore the cost of bio-oil production. Annual biomass
feedstock rates corresponding to 20 and 80 dry t/h pyrolysis plant
capacities have been frequently reported in previous economic
analyses