Wood energy in Georgia : operational systems--institutional/industrial, agricultural drying, educational

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NOV 1 9 1980
DOCUMENTS
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OCTOBER, 1980

INTRODUCTION
The 1973 oil embargo by the OPEC Countries, combined with extreme weather in January and February of 1977, caused a severe change in energy supply and demand situations. Wood energy had not been considered an alternate fuel source since fossil fuels were relatively cheap and available. In the winter of 1977, natural gas and heating oils were in short supply. Eighty-three industries and/or businesses in Macon were closed from a few days to weeks due to
fuel shortages. Similar conditions existed in the northern half of the state. The Forestry Commission and Georgia Tech Experiment Station invited business leaders to
meet and explore wood for energy. The Commission had inventoried the state wood supply and determined an enormous quantity of forest biomass was available. A model of a gasification system using wood chips was demonstrated and wood stoves and heaters were displayed and promoted.
Governor George Busbee and the General Assembly appropriated $500,000 to the Commission for wood energy effective July 1, 1978, an equal amount on July 1, 1979, and $400,000 on July 1, 1980.
Through a research study, a method of inventorying a timber stand in tons per acre was
developed. Wood harvesting equipment has been tested and proven effective to harvest sawtimber, peeler logs, poles, pulpwood, and energy wood chips in the same logging operation.
A wood gasification combustion process has been installed and is now operating at the Northwest Georgia Regional Hospital at Rome. A 500 h.p. boiler was retrofited to burn wood gas produced from whole tree chips with a maximum 65 percent moisture content. The gas is piped to
the burner in the boiler and replaces oil and natural gas. It is the largest gasification system using
green chips that we know of in existence. It is automatically operated and has a three-and-a-half
day fuel storage supply system.
Another major development is the agricultural crop dryer now ready for commercial use. It
uses whole tree chips (green) for fuel; is automatically operated using electric current existing on the farm; and can dry all kinds of grains, soybeans, and other crops with the exception of tobacco and peanuts. Hopefully, it can be modified to cure tobacco.
A new automatic fuel chip system has been installed in a junior high school at Blairsville, Georgia. It is now operating and has replaced an oil system.
The Commission employed Georgia Tech Experiment Station as consultant for the gasifier. Commission personnel have been responsible for the agricultural dryer, the school systems, and
other activities. Two additional school systems have wood chip facilities under construction. One
replaces oil and the other electricity. The new Correctional facility in Dodge County will have a wood chip system, and $200,000 has been alloted for it. Other state facilities are being investigated and data collected for wood energy application.
--A. Ray Shirley, Director Georgia Forestry Commission

THE SOURCE

IT ALL STARTS IN THE ABUNDANT
FORESTS THAT BLANKET THE STATE

Georgia has 24 million acres of com-
mercial forest land. Presently, the
growth amounts to approximately 24 million cords annually. Tree removal amounts to 14 million cords on 640,000 acres annually, leaving a surplus of 10
million cords.
On the average, 22 tons of waste per acre remains in the forest from logging
operations. A cord of wood is equivalent
to 3.3 barrels of oil for energy use. Another 35 million cords of cull trees are in the forest that are not merchantable unless used for energy. If 25 percent of the logging waste, excess growth and cull trees are used for energy, they would replace 42.5 million barrels of oil annually, representing a value of over $1 billion. This will be a major source of fuel for industry, institutions, schools and other
businesses in the state.
The Forest Management Department of the Commission has detailed data on the above assumptions.
The Forestry Commission has conducted ten harvesting demonstrations in
north and middle Georgia. A publication
by the Research Department of the Forestry Commission explains the whole tree

chipping process (Research Paper No. 4). Twenty-nine operators are presently using total tree harvesting machines in Georgia.
Detailed forest field studies have been conducted by the Commission and the U. S. Forest Service to determine the tons per acre of the biomass or the total tree chips. Volumes from 70-80 tons per
acre are common on the test sites. Some
areas of cull hardwoods are producing
100 tons per acre or more. Some studies
have been conducted concerning storage
and hauling wood chips. Removing the low grade hardwoods is
a tremendous benefit to the forest owner. Average cost for heavy mechanical site preparation in Georgia is $135 per acre plus $44 for mechanical tree planting, including trees. The site preparation can be eliminated by using total tree harvesting.
Certain total tree harvesting operations
are taking every stem down to one-inch
diameter. This is excellent site prepara-
tion for the establishment of a desirable stand of trees. Instead of having the above expense, the landowner can actually receive a profit by carrying out this type site preparation.

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A forester, at left, examines a cull tree that could be harvested for wood energy purposes. The scene above
is a small portion of the 24 million acres of forests that play a tremendous role in the economy of the
state.

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The Commission has established several one-acre study plots to demonstrate the various methods of harvesting and improving timber stands. Located on proper-
ty of Berry College, the plots are visited

by timberland owners and other interested persons.
Commission personnel serve as guides to point out the advantages of certain practices made on the property.

COMMERCIAL HARVEST PLOT

The commercial harvest plot is actually a demonstration of the conventional method of harvesting.
The plot shows the vast amount of
material left in the forest after the logger has taken out choice trees and left broken stems, large limbs, tops, and other residue that were once considered waste
but now represents a valuable resource when converted into chips or used for

firewood.
It is material that could not be feas-
ibly removed some years ago, but with the modern machinery of today - includ-
ing the feller buncher, grapple skidder and chipper - it represents potential added income to the landowner and a valuable contribution to the campaign to ease the energy shortage.

Estimate Pine Sawtimber
Pine Pulpwood Hardwood Sawtimber Hardwood Pulpwood Actual Volume Harvested Pine Sawtimber Pine Pulpwood Hardwood Sawtimber
Biomass Remaining on Plot Hardwood Pulpwood (no market) Tops, Undersize stems, limbs
Estimate of Total Biomass

Bd. Ft. 2,885
2,881

Cords
1.5 10.0
1.5
10.0

Tons 20.0
4.0
28.0
20.0 4.0
24.0
28.0 5.0
33.0 57.0

CONTROL PLOT

Two one-acre plots in the demonstra-
tion area are left in their natural state in
order that the observer can compare them with adjacent plots in which harvesting and other forest management practices

have been carried out. By leaving the stand intact, foresters
are able to point out several alternatives that a landowner could take if similar property were to be managed.

A Commission forester advises a land-
owner on the wisest and most profitable use of his timber. The bulk of Georgia's forests - some 23,267,500 acres - belongs
to private landowners.

Estimate
Pine Sawtimber Pine Pulpwood Hardwood Sawtimber Hardwood Pulpwood Total Merchantable Volume

Bd. Ft. 1,100
455

Volume of tops, limbs, cull and undersized trees
Estimate of Total Biomass

CLEAR CUT

Cords
3.7 3.5

Tons
7.7 9.8 3.4 10.2 31.1
33.9 65.0

The clearcut, or harvest cut plot, demonstrates total removal of the timber stand for the purpose of regenerating a more valuable acre of timber. Foresters graded the timber in the plot and it was sold for its highest value. After removal of the sawtimber, the undesirable trees, limbs and remaining biomass were chip-

ped. The two fold objective of the demonstration is to show landowners
how this method of harvest can save the
cost of site preparation, which would run approximately $135 on the type area shown, and at the same time realize additional income from the sale of chips produced from biomass

Estimate Pine Sawtimber
Hardwood Sawtimber
Actual Volume Harvested Pine Sawtimber Hardwood Sawtimber

Bd. Ft. 1,700
70
1,714 75

Cords

Tons
12.0
.6
12.0
.6

Estimate of Total Biomass

Actual Biomass Yield After Chipping

Estimated Site Preparation Cost - $0.00

Estimated Cost of Planting

(Including Seedlings)

-$44.00

Tons
93.0 96.0

SELECTIVE THINNING

The plot devoted to selective thinningsometimes called environmental harvesting-consists of typical North Georgia hardwood. Forestry crews cut out the small stems, hollow trees, species with poor form and other undesirable growth
in the understory. Desirable trees are left

for future timber crops.
The object of the study is to show landowners how they can vastly improve their timber stand and at the same time realize revenue from low grade and cull
materials that can be converted to chips.

Estimate Pine Sawtimber
Pine Pulpwood Hardwood Sawtimber Hardwood Pulpwood

Bd. Ft. 2,442
1,324

Biomass in tops, limbs, etc.
Actual Volume Harvested (cull, unmerchantabbllee treeess) Estimate of Total Biomass

Cords 6

Tons
17.1
9.9 17.4 20.9 48.2 113.5

SELECTIVE THINNING CONTROL PLOT

Estimate Pine Sawtimber
Pine Pulpwood Hardwood Sawtimber Hardwood Pulpwood Cull Unmerchantable Trees

Bd. Ft. 1,000
1,200

Estimate of Total Biomass

FIREWOOD PLOT

Cords 2.0 5.0

Tons
7.0 5.3 9.0 14.5 61.2
97.0

An acre consisting mostly of hardwood is set aside as a firewood plot to show the type of trees that can be pro-
fitably harvested for this purpose. It is

also emphasized that by taking out poor quality trees for fuel purposes, the entire stand is vastly improved.

Estimate Pine Sawtimber
Pine Pulpwood Hardwood Sawtimber Hardwood Pulpwood
Estimated Volume for Firewood Actual Volume Harvested - Firewood
Biomass in Tops, Limbs, Slash

Bd. Ft.
770
1,350

Cords
.5
6.2 6.0 6.7

Tons
5.4 1.3 10.1 17.3
16.8 18.8 25.5

Estimate of Total Biomass*

79.0

FIREWOOD PLOT (MARKED)

Estimate Pine Sawtimber
Pine Pulpwood Hardwood Sawtimber Hardwood Pulpwood
Total
Undersized Trees
Firewood Marked
Understory, Tops, Limbs, Etc. Estimate of Total Biomass

Bd. Ft. 2,420
1,575
3,995

Cords 2.9 7.0 9.9
7.0

Tons
16.9 7.7
11.8 20.3 56.7
7.5
33.8 98.0

*Due to estimated and actual figures, the total biomass does not reflect the sum of the column.

The demonstration clearcut plot is shown at the top, while the other photo provides a view of a plot harvested by the conventional commercial method.

The plot at right represents an improvement, or thinning cut. Poor quality trees taken from the plot were converted into chips, while high grade stock was released for better growth.
The control plot is left undisturbed so landowners and others can compare it with surrounding plots on which the various forestry harvest practices have been carried out.
The ribbon designates the trees in this firewood study plot to be left for higher quality products. The non-designated trees will be removed for firewood.

77?ese three machines have revolutionized the harvest of forests in recent years and
have made it feasible and profitable to reclaim woodland materials that were for-
merly considered wastes. The powerful feller buncher above is shown shearing a tree at ground level. The grapple skidder top right transports several trees at a time to the chipper shown at right. The chips are blown into a waiting van for transit directly to the Northwest Regional Hospital or to other locations where they will be used for other purposes.

.

GASIFICATION

A METHOD OF EXTRACTING ENERGY FROM THE FORESTS OF GEORGIA

The project to design, construct and install a wood gasification system

had its beginning in 1978 when the For-

estry Commission, with the engineering

assistance of the Technology Applications

Laboratory at Georgia Tech, began work

on this important development that would

greatly enhance the utilization of wood

energy.
A statewide search was made for a

demonstration site, and the Northwest
Georgia Regional Hospital in Rome was

chosen. Three companies entered bids for

the construction and installation of a
wood gasification system, and the con-

tract was awarded to Applied Engineering

Company of Orangeburg, South Carolina.

The gasification system has been com-

pleted and is now in operation. The eco-

nomics of the system are being closely

monitored to verify that the gasif ier meets

the performance criteria. Favorable re-

sults will bring about similar installations

in other state facilities and in private

industry.

The green total tree chips, approximately 2" x 2" mixed hardwoods and

softwoods, are delivered to the hospital

by chip vans with a capacity of 22-25

tons. The chip vans are unloaded by a

Phelps Hydraulic Unloader into a live

action hopper, which will hold one van

load of chips. From the hopper, the wood

chips are conveyed to a silo, which will
hold 314 days supply of wood (23,000 cu.

ft.) for the gasifier. The chips move from

the silo by a conveyor to the 25 million

BTU/hr. updraft gasifier as illustrated in

Figure 1

The

low

BTU

gas

(150

BTU/ft

3
)

is

piped 100 feet from the gasifier to the

wood gas burner. This burner has been

designed to replace the conventional nat-

ural gas and oil burner on the existing

500 h. p. boiler. The total tree harvesting contractor
who provides the wood chips will unload each van upon delivery and activate the
automative system that will carry the
wood chips to the silo. The system is de-
signed to allow the one boiler attendant
on duty to operate the wood gasifier as
the natural gas or oil boilers have been
operated in the past. A detailed control
panel inside the boiler room will keep the
boiler attendant informed of data relating to the operation of the gasifier.
The gasifier will use about three tons per hour of total tree wood chips with a moisture content of approximately 45-50 percent. The system will provide enough energy to produce 19,000 pounds of steam per hour, which will meet most of the hospital's steam needs for much of the year. Certain peak demands will require part-time use of another boiler. The wood gasifier will be utilized year-round
since an absorption unit is used to air condition the hospital during the summer.
The wood chips enter the gasifier through a rotary air lock. The vertical
pressure vessel is about 20 feet high and 8 feet in diameter. Temperatures inside the unit reach 2,000F., high enough to
chemically convert the wood chips to the combustible low BTU gas. Some drying of the wood chips occur in the top of the vessel as the hot gases move through the chips before going to the burner as shown
in Figure 2. Ash is automatically removed with an auger system.
This system is a fully operational, first generation system, which will provide real advantages over conventional fuels such as oil and natural gas. Applied
Engineering Company indicates that the
state should receive a payback on its investment in approximately two years.

A view of the gasifier at Rome is shown on the cover
while another is presented at left. Energy produced by the equipment will be used to both heat and air
condition the hospital.

WOOD GASIFICATION SYSTEM
NORTHWEST REGIONAL HOSPITAL ROME, GEORGIA
WOOD CHIP
DELIVERY

LIVE BOTTOM HOPPER
WOOD STORAGE
(3.5 DAYS)

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25 MILLION BTU/HR GASIFIER

LOW BTU GAS PIPE
100'

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COMBUSTION AIR SUPPLY

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EXISTING 19,000 LB/HR
GAS/OIL PACKAGE BOILER

Figure 1

At left, green wood chips are trans-
ported directly from the forests in conventional chip vans. Below, chip storage studies are being conducted by the Commission to determine
BTU content, moisture content,
deterioration and pile design.
WOOD GASIFIER
figure 2

DRYING WITH WOOD
WOOD CHIPS USED AS FUEL IN
DRYING AGRICULTURAL CROPS

Georgia's farmers presently spend
20 million dollars per year on propane gas for crop drying. After studying several systems, with plans to develop a
wood agricultural dryer, a unit originally
designed for lumber drying was selected and modified to attach to a crop dryer.
This wood chip furnace, developed by
Rettew Associates, Inc., will burn green
total tree wood chips and will generate
up to 3 million BTU/hr.
The wood chip furnace is mounted on a trailer to allow easy moves from one farm to another. A conventional John
Deere forage trailer was tested and proved very successful as a storage vehicle for
the wood chips. A Patz heavy duty agri-
cultural conveyor was added to the unit
to enable the wood chips to be conveyed from the forage trailer to the wood furnace. The forage trailer and conveyor was
synchronized with the electronic control panel of the furnace. Various safety devices are present on the furnace, enabling safe operation and shut-down if neces-
sary.
The wood chips are conveyed from the

forage trailer to a rotary air lock on the furnace. The chips pass through the rotary
air lock and slide down a sloping wall to
the pinhole grate, where the fuel is burned. Underfire air is blown through the
pinhole grate to keep the wood chips burning. From the area above the grates,
the hot gases pass over a six-inch firewall into a secondary combustion chamber and then into the firetubes of the heat exchanger.
The agricultural crop dryer produces hot air up to 200F. The hot air is moved from the furnace at 16,000 CFM. The wood chip furnace was tested as the heat
source for a conventional agricultural dryer. Preliminary data indicated that the fuel cost can be reduced by one-half using
wood chips instead of propane .
This system is being demonstrated throughout the state to show farmers
that wood can be used to dry agricultural
crops. Also, the Commission is studying the possibility of using the wood system to heat poultry houses and serve the agricultural and manufacturing interests of the state in other ways.

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The scene at left depicts how millions of
BTU's are wasted each year as land is cleared and the biomass burned. The wood burning unit, shown above, was

designed to dry lumber but is being adapted by the Commission to dry corn, soybeans and other grains.

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Many farmers dry their grains on the farm today before storing. The wood burning furnace using green wood chips, shown above, is demonstrated on a farm in South Georgia. A conventional forage
box, at left, is used to transport the green
wood chips from the local sawmill to the farm where the wood chip dryer is locat-
ed.

HEATING WITH WOOD
WOOD SOURCE OF FUEL USED TO
HEAT A GEORGIA PUBLIC SCHOOL

The Union County Junior High School in Blairsville, Georgia, is believed to be the only public school in the Southeast in modern times to be
heated by wood chips. A system installed by the Forestry
Commission is now operational at the
school and features the use of green
wood chips from a local sawmill as fuel. Unlike the pot-bellied wood stove that
stood in the classroom corner in a bygone era, the system at Blairsville is a fully automated method engineered by Dr. John G. Riley, a professor at the University of Maine. The system had met the requirements at three installations during
the harsh winters of that state before it was installed in the Georgia school.
The wood chips are transported to the school from the sawmill in a New Holland forage trailer, and then moved onto a live bottom hopper in the boiler room
by means of a conveyor. From the hopper, the chips travel by a
screw conveyor to a firebox which was constructed on the boiler room floor.

The Dutch oven-type firebox is direct fired and generates approximately 500,000 BTU/hr. The steam from the wood fire boiler heats a portion of the school building. Because of the extremely high combustion temperatures, the stack
emissions are very low.
The system replaces a fuel oil burner, which has been retained to provide the school with a dual system in the event of an emergency.
One unique feature of the system is the routing of excess heat from the stack
to the chip storage area to help dry the material.
The system will use approximately 700 pounds of chips per twenty-four hour day of operation and school officials have declared that the cost compared to the fuel formerly used shows a
a significant savings.
This project was a cooperative effort between the Georgia Forestry Commission, Tennessee Valley Authority, and the Union County School System.

A wood burning unit at the junior high
school, top left, is shown with an inside chip bin in the background. Bottom scene shows green wood chips which are available from many sawmills in the state. Schools may purchase wood chips

from local mills or from total tree harvesters. The Dutch oven type firebox, above, is connected to a boiler that provides steam for heating a portion of the
school.

FUEL
WHOLE TREE WOOD CHIPS
8 million BTU'ton
NATURAL GAS
1,000 BTU/cu.ft.
NO. 2 FUEL OIL
140,000 BTU/gal.
ELECTRICITY 3,415 BTU/KWH
PROPANE
92,000 BTU/gal.

RELATIVE ENERGY COSTS CALCULATIONS $/Million BTU

PRICE
PER TON
S10.00 15.00 20.00 25.00 30.00
PER THERM.
S .25 .30 .40 .50 .60
PER GALLON
$ .60 .70 .80 .90
1.00
PER KWH
S .030 .035 .040 .045 .050
PER GALLON
S .45 .50 .55 .60 .65

ENERGY COST
PER MIL. BTU
$ 1.25 1.87 2.50 3.12 3.75
PER MIL. BTU
$ 2.50 3.00 4.00 5.00 6.00
PER MIL. BTU
$ 4.29 5.00 5.71 6.43 7.14
PER MIL. BTU
$ 8.78 10.25 11.71 13.18 14.64
PER MIL. BTU
$ 4.89 5.43 5.98 6.52 7.07

AVERAGE COSTROME -Oct. 1980
WHOLE TREE WOOD CHIPS
(delivered to
Rome) Per Ton $16.32 ($2.04)*

AVERAGE COST

ROME

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WHOli
WOOD CHIPS

$13.60 ($1 r

NATURAL GAS
Per Therm. $ .35 ($3.50)*

NATURAL GAS
m.
i
$

NO. 2 FUEL OIL
Per. Gal.
$ .86 ($6.20)*

No. 2 FUEL OIL
$ .43 (S3 .1'

ELECTRICITY
Per KWH
$ .045 ($13.18)*

RICITY
J
KWH
S 038 ($10.98)

PROPANE
Per. Gal.
$ .68 ($7.40)*

PROPAr
$ .45

f
Per

Million

BTU

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ACKNOWLEDGEMENTS
-APPALACHIAN REGIONAL COMMISSION -GEORGIA TECH EXPERIMENT STATION
-U.S.D.A., FOREST SERVICE
-TENNESSEE VALLEY AUTHORITY -BERRY COLLEGE
-GEORGIA DEPARTMENT OF HUMAN RESOURCES

GEORGIA
FORESTRY ?M\*$
A. Ray Shirley, Director
John W. Mixon, Chief of Forest Research