Wood-Chip Heating Systems - Biomass Energy Resource Center

An Important Relationship:
Fuel Source, Delivery Vehicle and Storage Bin
One of the most important tasks in putting
together a successful biomass system is building
a fuel storage facility that will meet both the
immediate and long-term needs of the system, its
owners, and its operators. The fuel supplier, fuel
type, and delivery vehicle used all may change over
the life of the installation.
First, the bin must be sized adequately (as
discussed on the next page). An undersized bin
will constrain the system throughout its life. The
bin must also be conveniently located for deliveries
from large trucks, with consideration for snow
removal and parked vehicles.
Second, the bin should be capable of receiving
deliveries from vehicles of different sizes and
different types. Any facility may, at various points
in the future, want to order fuel from a sawmill, a
whole-tree chipper, or a trucker who hauls biomass.
These various suppliers might use small or large
dump trucks, dump trailers, or self-unloading vans.
In the Northeast, self-unloading tractor trailer
vans (also called live-bottom trailers) are the most
common type of delivery vehicle. These trailers look
just like a conventional tractor trailer except that
they have a hydraulically operated fl oor system that
pushes fuel out the back (see photo on page 52).
The fuel bin should be confi gured to eliminate
or minimize any time facility staff must spend to
assist the driver during deliveries. The need to have
staff involved in unloading may also constrain the
supplier’s delivery schedule. For a larger system
with frequent deliveries, these considerations will
be important.
Bins that fi ll by gravity are best, and the bin doors
should enable quick unloading (30 minutes on
site for live-bottom vans, 10-15 minutes for dump
trucks). Gravity-fi ll bins are located below grade,
or have a ramped-up driveway so that trucks can
easily dump fuel down into them (see photo above).
Fuel suppliers prefer delivering to facilities where a
full truck can be unloaded quickly. Suppliers may
charge more for fuel delivered to sites that take two
hours per delivery.
Bin door design needs to accommodate the
possibility for delivery from dump trucks. While
the door cannot be high enough to accept a fullyextended
dump body, it has to be tall enough so that
the truck, with its body up, can back part way into
the door so that the fuel will slide down into the
bin without unnecessary spilling onto the ground.
There should be a paved apron in front of the doors,
to facilitate scooping up any spilled fuel.
Gravity-fi ll bins have a strong advantage over
bins that require mechanical fi lling equipment.
Bin-loading equipment carries an added capital cost
and means another set of mechanical devices that
requires maintenance and can fail. The electricaldemand
charges of motors for bin-loading or
bin-leveling equipment can add signifi cantly to
electric bills and can wipe out some of the cost
advantage of burning an inexpensive fuel (see the
sections of Chapter Ten that deal with bid forms and
assessing bid information).
In addition to self-unloading vans and dump
trucks, regular tractor trailers may be readily
available to deliver chips. These trailers must be
unloaded at a loading dock using a small tractor
or skid-steer loader. The loader drives right into
the trailer, scoops up fuel, backs out, and deposits
the fuel into the storage area. Most institutional or
commercial biomass burners decide from the start,
however, that they do not want to be tied to the labor
and equipment associated with unloading fuel from
conventional (not self-unloading) tractor trailers.
WOOD CHIP HEATING SYSTEMS
21