Note: Descriptions are shown in the official language in which they were submitted.
Biomass is a renewable energy source and a renewable
source of chemical feed stock and while a principal fuel at one
time, its use for that purpose declined until recently. Its use
today is increasing because of the high cost o other fuels and it
would be used more extensively not only for domestic but also
industrial uses if it were more convenient to handle and if its
moisture content could be reduced, on an economical basis, to
increase its value as a -Euel and feed stock, one major facet of
value enhancement being the lower capital costs associat~d with
conversions to dry biomass particles~
Wood, as a fuel for domestic uses, must be harvested,
typically in four foot lengths, later cut into lengths appropriate
for fireplace, furnace, stove or heater uses, split, air dried,
and stored As a consequence, if such wood is purchased ready
for use, even in cord lots, its cost is substantial but in stoves
and heaters of efficient design, it can have a thermal efficiency,
if air dried, as high as sixty percent. The isture content of
air dried wood is typically in the neighborhood of twenty-five
percent.
That the thermal efficiency of wood is inherently
dependent on its moisture content is established by noting that
green wood has, on the average, a moisture content in the neigh-
borhood of fifty percent so that, for example, thirty-five pounds
of kiln dried wood will have lost about thirty pounds of water,
wet basis. Wood that is termed "kiln dry" has a moisture content
in the five to eight percent range, Assuming the burning of that
wood when green, the BTU required to drive off that water repre- /
sents a minimum loss of about eight percent in heating value ~ n
addition the substantial volume of air required to keep such wood
burning represents an even greàter loss and it has been determined
-2- ~
~ 5 ~
that the heating capacity of green wood is less than two thirds
that of kiln dry wood at the time of burning.
Drying biomass particles at a remote site increases its
value for use as chemical ~eed stock in that it reduces the end
product cost, removes water vapor or steam from the end product
and, in some cases, when water is required to process the feed
stock, remote drying allows waste steam and low temperature water
or weak combinations of useful chemicals or both, singly or in
combination, to be reclaimed when added to the dry feed stock.
It has~ of course, been recognized that wood harvesting
for lumber and paper mills results in much waste in the form of
branches, tops, and trunks found, after cutting, to be unfit for
useO As far as we are aware, no economically attractive proposal
has been made enabling such waste wood to be converted into fuel
or chemical feed stock~
The problem has been that in the past the collection,
handling and transportation of the many small crooked pieces of
previously wasted tops, branches and culls has been more expen-
sive than their value as raw material for paper, boards, or other
manufactured products. Particularly this is true when one con-
siders that most i~ not all of such manufactured products require
that the bark ke removed prior to such use and that these small
crooked pieces cannot be economically de-barked. Now, however,
the cost of conventional fuel has increased to the point that
certain types of wood and wood-waste can now compete with coal,
gas and oil as a source of fuel and feed stock. Tops, branches
and culls now left in the forest could now also be competitive
as fuel or chemical feed stock if a method of economical collec-
tion, handling and transportation were available. Another source
of wood wastes for fuel are so-called manufacturing wastes which
have little value unless upgraded prior to transportation.
~ or instance, one source of particles could be logging
operations in the United States which leave the equivalent of
five hundred million barrels of oil rotting on the ground each
year. In addition forty-five percent of all forests in the United
States are non operable wood lots which are overstocked with small
trees. If sufficient market for forest residues can be developed
as much as ten million barrels in oil equivalent of forest
residues can be economically obtained each year on a sustained
and renewable basis by intergrating logging operations to remove
both round wood and residues. ~y developing a market for these
residues the presently non-operable (non-commercial quality) wood
lots can be returned to high productivity on shorter rotation while
providing income to the landowner; profit to the logger; and
replacement of foreigh oil. However, even with the pressures
created by substantially higher oil prices since 1973, markets
for th2se residues have developed very7 very slowly. Capital
costs for traditional conversion technologies have been too high
and pay out periods too long so that potential users have per-
ceived risks too high for such capital proj~ects when comparedwith other opportunities for investment having lowér perceived
risks and shorter pay out terms, What is needed is new technol-
ogy which will allow conversion by means requiring substantially
lower capital moneys to be supplied by the user. For instance,
but not by way of limitation, a power boiler of a size used by
the pulp and paper industry may be installed for dry wood
particles at a capital cost from twenty percent to thirty percent
lower than that required for green particles. Further capital
and operating economies are gained by transferrlng the surge pile
which is traditionally placed directly in front of the conversion
-4-
~ S 9 ~ ~
facility to locations in part within the logging operation and in
part within the transport system This is possible when chips are
dried before transport because dry chips do not freeze~ deterio-
rate or spontaneously catch ire as do green particles By
employing the technology taught by this application, vendors of
particles may offer dry particles which reduce the perceived
risks and the payback term so that markets for residue particles
from logging operations, for instance but not by way o~ limitation,
may prevail over other money saving projects which is seldom the
case employing traditional green particle conversion means~
To fulfill this objective a simply system not requiring
expensive clean-up of products of combustion has been needed but
has not been heretofore available in a ~orm that would allow
remote drying in a safe manner which assured ~reedom from carrying
sparks over to the dryer~ The US8 of a gasifier which by design
delivers essentially a stream of gas and suspended liquid or
vapor phase materials and which stream does not require expensive
and power consuming stream cleaning devices either before or ater
combustion makes remote drying economically possible As an
example but not limitation, an economic analysis by Austin
Associates of Auburn, Maine, employing recognized accounting
methods shows a conversion system converting dry particles
received from the system which is the subject of this application
at a moisture content o~ ~ifteen percent wet basis cansave sub-
stantial annualized costs when paying ~ifty dollars per ton for
dry particles during the payback term while employing dry fuel
conversion technology as opposed to paying $18.75 per ton for
green particles at 50% M.C. while employing more expensive green
particle conversion technology. Another study by ~nergetics
Incorporated of Columbia, Maryland, shows that the method and
~ 9 ~ ~
apparatus taught by this applica~ion when employed to process
forest residues can pro~itably process and deliver loads of
15% M.C. wood particles at ~ifty dollars per ton, This study
was completed in January 1984,
The st economical mode of handling and transporting
such waste wood is that o~ reducing such material to particles
and then removing the unwanted water as close as possible to the
site where they are available prior to transporting the wood
particles beyond that area. Such a method has not been previously
practiced ~or the want of the right combination of equipment and
technology applied in the proper sequence to make the collection
of this waste wood economically attractive.
The general objective of the present invention is to
provide a basis enabling biomass including waste wood and bark to
be processed at or near the site where it is available in the
woodland or some other suitable site in the form of particles
within a predetermined size range and processed for use as fuel
or chemical fead stock on an economical basis.
In accordance with the invention, this objective is
attained by utilizing particles as received from chippers and/or
hoggers and produced from the harvested material with those from
a chipper or chippers delivered to a gas producing section where
they are subjected to gasification to provide at least one stream
of hot fuel gas, Such particles from chippers and/or hoggers
are also delivered to a drying section where the hot fuel gas is
utilized in a manner enabling the moisture content of the par-
ticles to be reduced to a wanted extent without adversely affect-
ing them, A relationship is established between the volume of
particles delivered to the gas producing section and the volume
of particles delivered to the drying sectlon such that the
~L~5~
moisture content of the dried particles is reduced in the
approximate range of five percent to ~orty percent, we~ basis,
while maintaining an economic advantage between the dried par-
ticles and the value of undried particles. Lt will be appreciated
that an important factor in determining economic advantage is the
annualized costs of converting to dry particles during the pay~
back period for the capital equipment required for converstion.
The relationship between the volume of particles to be
utilized in producing hot fuel gas and the volume of particles to
be dried on an economical basis is dependent on other uses for
which hot producer gas may be re~uired in accordance with various
other objectives of the invention which include the use o such
gas to provide fuel for a prime mover by which power is provided
for such uses, separately or in various combinations, as operating
particle forming means, conveyors, blowers, hoggers, and com-
pacting means. In addition, the drying section may include a
plurality of dryers of the same or dif~erent sizes and types.
Wood, including waste wood and bark at or near the
harvesting or other suitable site is converted into particles
which are thereby so transformed from their original crooked and
unwieldy state, that they can now be economically handled, com-
pacted and then transported with signi~icant cost savings. A
dryer is provided which may be either of the batch type or the
continuously operated type. I~ the former the dryer may be filled
and emptied by any suitable means, while if the latter conveying
means are used. The apparatus may include means to package pre-
determined amounts of dry particles in combustible material to
provide fuel units that are protected against absorbing moisture,
a bulk delivery outlet, or both.
Particles are delivered along a path which includes at
least one gas producing section which may be operated at the site
where the particles are produced or at some other convenient site
for the purpose o converting particles to fuel gas thereby pro-
viding fuel to heat the dryer.
In most embodiments of the invention, the major portion
of the producer gas is used for particle drying in the drying
section and a minor portion employed for heating particles prior
to their delivery to either the gas producing section, the drying
section, to both sections, or to a separate drying section to
provide fuel for the same gas or another remotely located producing
section, in any case the particles dried at the drying section on
an economically advantageous basis.
As specific examples of uses of a minor portion of hot
producer gas, reference is made to the following uses either
singly or in various combinations; fuel to power the particle
producing section, fuel to power conveyors and blowers required
to operate the drying section, or sections, and fuel by which
drying in another drying section may be effected with both the
major and minor portions of hot gas derived from a single gas
generator or with the minor portion derived from a second gas
generator.
When gas rom a producer section is employed to produce
power it is first cleaned and cooled and then consumed in an
internal com~ustion engine or a turbine. The hot air from the
heat exchanger used to cool the gas is preferably delivered to
the dryer. The dry particles may be carried to a station where
they may be packaged for distribution or carried in bulk to a
consuming site provided that the processed particles do not
absorb moisture in transit.
While the method of invention is in general apparent
-~s~
from the above description of the apparatus, an essential feature
of both method and apparatus is that the efficierlcy of the gas
producing means is such that the volume of particles utilized by
the gas producer section for its unctions is less than the
volume of dried chips with the ratio between the two volumes such
that an economic advantage is maintained between the dried par-
ticles and the BTU requirement to efect their drying.
The term "particles" as used herein and in the claims
means har d or soft wood chips and wood and bark fragments, no
matter how formed. Whir~e~ such fines as sawdust can be accommodat-
ed in amounts in ~he fuel units and gas producers can be designed
to utilize fines, the particles delivered to the gas producing
æction must be those as produced by properly operated and main-
tained chippers for the gas producing section The elimination
of slivers from the particles may be accomplished by screening or
by features built into the chippers. For the drying sections,
the particles may be those produced by chippers and/or hoggers.
It is thus established that particles of different nature and
properties may flow simultaneously along the various paths if
such is desired. The invention is herein discussed primarily with
reference to the forming of the particles by chLppers~ by way of
example but not of limitation,
In some cases, the wood particles are chips such as are
produced for pulp mill use, in other cases smaller particles are
employed, and in yet another situation both types of particles
may be used and divided between the two paths as required for the
efficient production of the dry particles.
In accordance with the invention, the moisture content
of the dried particles is in the approximate range o from five
to forty percent, wet basis, While the lower the moisture content,
_9_
~g~19~1
the greater the advantage in reducing transportation costs, capi-
tal costs for conversion an~ the greater the thermal value, the
percentage of the total production required to effect low level
drying is also increased. At the higher levels, the advantage
may be simply -to bring certain partlcles into the moisture range
most desired for existing conversion equipment. For the lower
ranges an ever increasing variety of new technologies is avail-
able which reduce capital costs of conversion.
In one embodiment of the present invention the drying
step reduces the moisture content of the particles to a moisture
content within the approximate range of from five to eight per-
cent and the particles are for use as fuel in stoves, heaters,
and furnaces where the combustion chamber is air tight.
In another embodiment of the present invention the dry-
ing step reduces the moisture content of the particles to a mois-
ture content within the approximate range of from nine to sixteen
percent and the particles are for use in stoves and heaters where
the combustion chamber is not air tight.
In a further embodiment of the present the drying step
reduces the moisture content of the particles to a moisture con-
tent within the appro~imate range of from seventeen to forty per-
cent and the particles are for use as an all purpose fuel.
A particular objective of the invention is to providevapor-protected dry particles of a packaged size such that they
may be used in any domestic heating equipment as an easily
ignited unit with each unit of a size and weight that may be eas-
ily handled.
In the accompanying drawings, preferred embodiments of
the invention are illustrated:
Fig. 1 is a schematic view of the apparatus required to
-- 10 --
carry out the invention and enabling the several steps required
by the method to be readily understood;
E'ig. 2 is a like view of the particle producing section
of apparatus utilizing two chippers, each for producing par-ticles
of differen-t sizes;
~0
- lOa -
~J
Fig. 3 is a like view of the corresponding
part of apparatus in accordance with ano-ther
embodiment of the invention where the production
of a single chipper is divided into -two parts with
the particles of each part within a predetermined
di~ferent size range;
Fig 4 is a schematic view of another
embodiment of the invention, the apparatus of
the type illustrated in Figure 1 but with the
gas producing section provided with two
separate producers;
Fig. 5 is a schematic view of yet another
embodiment of the invention, the apparatus of
the type illustrated by Figure 1 but with
separate supplies of particles; and
Fig. 6 is a like view of apparatus in which
a minor portion of the hot gas is employed to
effect particle drying at an additional station.
The Preferred Embodiments of the Invention
The apparatus illustrated by Figure 1 includes a chipper
generally indicated at 10, provided with an infeed chute 11 for
harvested wood. The chipper 10 has first and second outfeed con-
veyors 12 and 13, respectively, and not detailed as they may be of
any type that meets the requirements of a particular installation.
Wood chippers are well known with a typical construction
shown in United States Patent No. 2,299,248 and efficient chippers
are manufactured by Morbark Mfg~ Co., Inc of Winn, Michigan, and
M. B~ Company, Inc. of New Holstein, Wisconsin.
The first conveyor 12 delivers particles to a dryer
generally indicated at 14. The dryer may be a drum dryer or one
~ ~9 ~9 ~
such as is manufactured by C. G. Sargentls Sons Corporation of
Graniteville, Massachusetts, or o some other satisfactory type,
and it may be either o~ the batch type or one operating continu-
ously. The dry particles are shown as being delivered from the
dryer 14 to a station 15 where the particles are packaged in
combustible, vapor proo~ materials ~o provide fuel units 16 of
desired dimensions and weight that are ready to be burned. The
particles may also be transported in bulk when properly protected
from moisture via alternateconveying means.
A power plant for operating the apparatus included an
internal combustion engine or turbine 17 and a generator 18 driven
thereby. The chipper 10 may be driven directly by the engine 17,
or~ as shown, by a motor driven by the generator output. The out-
put of the generators 18 is preferably adequate ~or the operation
of all components of the apparatus thus to avoid or minimize the
use of other portable generators
The second conveyor 13 delivers particles to a gas
producing station or section generally indicated at 19, and con-
taining at least one gas producer or generator, com~only called
a gasifier regardless of its specific construction, see United
States Patent No. 2,4~0,940 ~or one type o~ such a producer, The
hot exhaust gases rom the engine 17 are employed to help dry the
particles, preferably those used in gas production, by discharging
them into the conveyor 13 via a conduit 20 either in a counterflow
relation to the chips being conveyed or, as shown, into the con-
veyor 13 adjacent the chipper. The conduit 20 contains a blender
or cooler 122 operable to bring the exhaust gas temperature into
the approximate range of ~rom 200F to 600F. Such gas producers
generate a hot gas that, as is well known, is a useable fuel. To
that end, the gas producing section 19 has a conduit 21 provided
~12-
4~
with a cooler 22, preferably of the air cooled type, and a filter
23 in communication with the intake of the engine 17. In accor-
dance with the present invention, the gas producing section 19
has a second fuel delivery conduit 2~ in commun:Lcation wi-th a
burner 25 the hot products of combustion from which are delivered
into the interior of the dryer 14 as the drying medium for the
particles therein. Warm air from the cooler 22 is delivered to
the dryer 14 by a conduit 26 to moderate the -tempera-ture of the
hot gas stream from the burner 25 since the gases may reach
2000F or higher and the temperature within the drying chamber
should be within the approximate range of 200F - 600F, prefer-
ably between 2sooF and 300F. Desirably, and as shown, there is
alternate conveying means 27 leading from the dryer 14 to a sta-
tion 28 from which bulk delivery is started. Desirably the effi-
ciency of the gas producing step is approximately ninety percen-t
and the volume of particles sub;ected to gasification is not in
excess of 15% of the particle production. Suitably the effi-
ciency of the gas producing step is approximately ninety percent
and the volumes of particles sub;ected to gasification is about
12% of the particle production. Alternatively the efficiency of
the gas producing step is approximately ninety percent and the
volume of particles subjected to gasification is about 18 1/2% of
the particle production. Alternatively the efficiency of the gas
producing step is approximately ninety percent and the volume of
particles sub;ected to gasification is about 13% of the particle
production.
Reference has been made to the fact that the dryer may
be either of the continuous type or the batch type. If the for-
mer, the associated conveyors are to be operated continuouslywhile, if of the latter type, the associated conveyors are to be
operated intermittently as required for its loading and unload-
ing.
The components of the apparatus are adapted t'o be
transported from one harvesting site to another and set up where
- 13 -
~S~
harvested wood can be delivered to the chipper 10 on the most
efficient and economical basis. The site may be where other har-
vesting operations are in progress. Where the apparatus may be
located at a more or less permanen-t and centrally loca-ted collec-
tion site, the feature of mobility is of less irnportance but asit is preferred that waste wood, usually left ln the forest, can
be harvested and converted into fuel, mobility of -the appara-tus
is a desirable feature.
~0
- 13a -
It should be noted t~at, whi~e desirable and preferred,
it is not necessary that the particles be bagged directly upon
their discharge rom the dryer, for they may be carried to a
remote bagging s-tation provided that they can be protected in
transit from absorbing moi.sture It should also be noted that
for industrial uses or for transporta-tion to a bagging station,
the station 28 may be one where the particles are compacted by
vibration. In the bulk shipment of dried particles means pro-
viding protection against moisture absorption during transit of
the unpackaged dry particles are in most areas, a requirement.
As illustrated by Figure 2, a chipper lOA and a second
chipper or hogger llOA may be used with the latter used to process
wood from a different source than that for use in the chipper lOA.
In Figure 2, the output of the chipper llOA is shown as
delivered into the conveyor 13A provided with a branch 29 to the
dryer 14A and with a ga.te 30 ènabling, depending on the volume of
particles being produced, only the supply of particles needed for
the operation of the gas producing section l9A to be delivered
thereto with the remaindex transferred to the dryer 14A.
In Figure 3, the chipper lOB is adapted to so process
wood that particles may vary considexably in size and accordingly
it includes an outfeed section 31 including a screen 32 which
rejects splinters from the flow to the gasi~ier. Small gasifiers
require protection from splinters as small as three inches or less
in length while larger gasifiers need protection from splin~ers
o~ only iour or more.inches~ The degree of protection must be
that which assures reliable feed into the gasifier~ In still
another situation it may be desired to provide the screening
function shown at 33 be performed after drying is accomplished.
In that case station 33 would appear after the dryerv
~ 5~
Turning again to the gas producing sectio~ o~ the
previously described embodimen-ts, each such section may contain
more than one gas producer depending on such factors as the gas
volumes needed and the size and weight of the producers, particu-
larly when portability is a consideration.
Figure 4 illustrates apparatus where more than one gas
producer is a desirable feature. That embodiment o the invention
is similar to that of Figure 1 in that a power plant consisting
o an engine 17C and a generator 18C provide the electricity to
opera~e the motors that drive the chippers lOC, the conveyors 12C,
13C, and ~he conveyor of the dryer 14C and the conveyors of what-
ever equipment is provided to handle the dried chips.
As the volume of gas required ~or the eficient opera-
tion of the dryer 14C may be substantially greater than that
required by the power plant, the gas producing section has two
gas producers, the gas producers l9C and ll9C. The conveyor 13C
is provided with branches delivering wood chips to the gas
producers l9C and ll9C, respectively, in quantities appropriate
for their operation.
It should be here noted that the moisture content of
the chips delivered to the gas producing section o any apparatus
in accordance with the invention is an important factor. In
Figure 2, the exhaust gases rom the engine 17 were used in chip
drying as by their introduction into the conveyor 12. In Figure 4
if the moisture content o the chips to be delivered to the gas
producers is too high, part of the hot gases fro~ the burner 25C
may be delivered to the conveyor 13C via the valve controlled
conduit 37 and the conduit 20C.
In Figure 4, the bagger 15C is shown as including a
vibrator 38 and the bulk delivery 28C as a trailer body having a
-15-
~ ~ 5~
vibrator 29 therein, both vibrators operable to reduce bulk by
about ten percent.
While the conveyors indicated in Figuxes 1 through 4
are continuous screw type conveyors for conveyi~g short distances
these distances may be incrPased by employing vehicles to transport
particles to nearby locations should the location at which the
particles are produced or are otherwise available be inappropriate
to also operate the dryer section. It is intended, however, to
keep such distances small in relation to the total distance over
which the particles travel to the use site~ In this way the
transportation savings generated by the described method may be
maximized.
The embodiment of the invention illustrated by Figure 5
is generally similar to that illustrated by Figure 1 but is
essentially a drying station as chippers are not shown as the
particles may be produced elsewhere. The dryer 14D may be of the
continuous or batch type and, if the latter, it may be charged
and emptied by means other than conveyors. It will also be noted
that the exhaust gases from the engine or turbine 17D are employed
to assist in drying particles carried to the dryer 14D by the
conveyor 12D.
The embodiment of the invention schematically illustrat-
ed by Figure 6, has a gas producing section, generally indica~ed
at 2S, which may have more than one gas producer o~ a type pre-
viously referred to.
The major portion of the producer gas produced in the
section 35, is, as previously illustrated and described, delivered
via valve controlled conduits 36 to the dryer l~E, after being
burned and sufficiently cooled to enable the hot products of com-
bustion to be used to dry particles therein. The dryer l~E may
-16-
be of a batch ~ype or one through which particles are continuously
conveyed.
A minor portion of the hot gas produced in the section
35 is also delivered, via valve controlled conduits 37, burned
and sufficiently cooled to enable it to be used in particle
drying, to a drying station 38 which may be a portable dryer but
is shown as of a type to accommodate a portable bin 39 which
while of a capacity substantially less than that of the dryer l~E,
accommodates that volume of particles that, when suitably dried,
enables a continuous drying operation to be started or that is
required in the drying of a single batch, the dryer 14E then
being of the batch type. In any case, the particles dried by the
minor portion of producer gas are employed, when needed, as a fuel
supply for the gas produ~ing section, a bin 39 being shown in
dotted line in position for that purpose
A valve controlled conduit 40 is provided that may be
used to deliver a minor volume of hot fuel gas from the gas
producing section for another purpose or purposes, as fuel for an
internal combustion engine9 for one e~ample.
While the method is generally apparent from the fore-
going description of the apparatus, an important feature of the
invention is that it requires only a minor part of a wood par-
ticle production to provide the needed energy to produce a dry
particle output.
A summary of the invention and its operation is
represented by the method which requires the delivery o particles
as produced by commercially available hoggers or chippers proper-
ly operated and maintained from which particles such as splinters
may be rejected if their presence interrupts particle flow to the
gasifier, or to the dryer or if a similar condition applies to
-17-
~ ~ ~9 ~ ~r3
the conversion device which consumes the dry chips. The gas
producing section provides at least on0 stream of hot ~uel gas
which is utilized in a manner to effect the reducticn in the
moisture content of the particles at the drying section to a
wanted extent in the approximate range of 5% - 40% (wet basis)
with the relationship between the volume of particles utilized to
produce hot fuel gas and the volume of dried particles such that
the overall economic advantage is maintained. That relationship
permits a minor portion of the hot fuel gas to be employed for
such othe-r purposes as to provide fuel for a prime ver by which
energy is provided to operate particle forming equipment, con-
veyors, blowers, baggers and compactors or vibrators and addition-
al drying or heating functions either during or prior to their
delivery to a gas producing section.
Where the moisture content of the chips being delivered
to the gas producing section of apparatus in accordance with any
embodiment of the invention is too high, part of the hot products
of combustion may be directed to ensure that the delivered chips
are suitably dry.
It will be apparent that wood particles in accordance
with the invention will absorb isture under normal atmospheric
conditions unless suitably protected. Discussion above relative
to the potential costs of packaged fuel in accordance with the
invention utilized a final moisture content of fifteen percent.
A desired final moisture content in the approximate range of from
five percent to forty percent may be practiced to reach the
requirements of a specific end use.
A situation where economic advantage exists ~or drying
only to forty percent wet basis is when it is desired to consume
soft wood which naturally contains more water than hard wood in
-18-
t~
a system designed for hard wood. In this ins-tance the removal
of only a small fraction of the water crea~es a market or soft
wood particles which could otherwise not be used.
Reference has been made to the packaging of dried
particles to provide fuel units. The dried wood chips are packag-
ed or shipped in bulk with a volume reduction in the neighborhood
of ten percent affected by vibratlon. The drying proc~ss reduces
the volume of the particles by about ten percent. When this
reduction in volume is utilized by topping up the load with dry
chips th~ volume capacity and the weight capacity of a vehicle
can be achieved simultaneously.
Particles used for chemical feed stock as with particles
used for fuel benefit from both types of conversion processes
by virtue of reducing final product costs, improving the final
operation of the process and thereby enhancing the value of the
dried particles.
-19-
