Transportation - Engineering and Science of Biomass Feedstock Production and Provision - page 153

that the volume and weight limits can be reached simultaneously. The main differ-
ence between ships and trains is that for a given loading volume, trains, supported
by rail, can, in principle, accommodate densities much higher than the density of
water, and ships cannot, since sufficient residual buoyancy must be maintained.

6.4.4 Pipeline Transport

Pipeline transport of biomass in a slurry form is an attractive idea, since the pipeline
itself is stationary and the material is inherently contained. In the paper industry,
slurries are used to convey pulp, but only for relatively short distances. High-
concentration slurry disposal (HCSD) is a modern approach to remove fly ash from
power plants over distances up to 10 km with a solids fraction of 70 %. For biomass
to follow a similar strategy, the biomass density should ideally be similar to that of
the carrying fluid (typically water), which is not the case.
The economics of pipeline biomass transport have been studied, leading to the
conclusion that for flows over two million dry ton yr −1 and distances ranging from
100 to 500 km, pipeline transport is less expensive than truck transport [ 41 ].
However, technical limitations render the concept unfeasible since research has
shown that the biomass will readily absorb the carrier fluid: woodchips absorb water
from an initial water content of 45 % to over 60 % in a matter of hours. This reduces
the lower heating value of the material to virtually nil. The same material in oil
reached an oil content from initially zero to over 30 % after 120 h [ 42 ]. This leaves
the possibility of adding biomass such as woodchips to an oil flow in existing pipe-
lines, but the oil-pumping infrastructure, including pumps and valves, is dependent
upon the fluidic behavior of oil, and adding biomass would require major engineer-
ing adaptations. The consensus found in the literature is that pipeline transport is not
a feasible option for biomass transportation.

6.4.5 Biomass Transportation Logistics

Supply and biorefinery logistics represent critical barriers in energy generation from
biomass [ 3 , 6 , 11 , 43 , 44 ]. Biomass supply logistics are dependent upon the conver-
sion technology utilized, production capacity (i.e., feedstock demand), feedstock
type, yield (i.e., feedstock supply) as well as pathways and technologies that make
feedstock supply meet demand. In general, the components of biomass feedstock
supply chain mainly include biomass harvest/collection, baling, loading, transport in
the field and/or long-distance, transloading, storage, mechanical comminution and
feedstock transformation (e.g., pelletization and torrefaction). At tactical and opera-
tional levels, feedstock transportation logistics are dictated by farm and biorefinery
location, daily or hourly biomass quantities to be transported, handled and mechani-
cally processed, numbers and time schedule of harvest machines, transportation