Mineral Facts and Problems: 1960 Edition Page: 453

                                
LIGNITE AND PEAT

peat-fueled power plant placed in operation at
Ferbane, Ireland, has similar pulverized-fuel-
fired boilers. Several large power stations are
operating in Germany, Norway, Finland, and
Sweden also. In the United States, the Minne-
sota Iron Range Resources and Rehabilitation
Commission has worked on the problem of
using peat as a fuel for beneficiating low-grade
iron ore. The University of Minnesota and a
number of other organizations are also con-
ducting research on peat, not only in conjunc-
tion with coal investigations but also from the
standpoint of peat utilization as such.
Because of its low heating value and high
bulk, which make transportation uneconomical,
peat can be used only as a local fuel. The
availability of other high-grade fuels and coals
at competitive prices has essentially limited the
use of peat in the United States to agricultural
applications where its chemical and physical
properties, such as its ability to retain water
and its degree of acidity, are of distinct
advantage.
Peat production methods in the United
States are relatively simple, and most of the
techniques used have been developed by indi-
vidual operators to meet conditions that are
peculiar to their specific operations. Conven-
tional excavating and earth-moving machinery
is generally used to recover the peat, which is
then dried, shredded, and either packaged or
loaded and sold in bulk.
The technology associated with the utiliza-
tion of peat as a fuel or source of chemicals, as
practiced in Europe, is more complex. Some
of these techniques are described in the section
on research.
USES
LIGNITE
Like other ranks of coal, lignite has been re-
placed to some extent in domestic and indus-
trial heating by more convenient and plentiful
supplies of oil and gas. On the other hand, the
industrial use of lignite is in its infancy. It
is an inexpensive, plentiful fuel (either as
mined or briquetted) for heating and power
generation, as a source of industrial carbon for
decolorizing and purifying solutions (sugar re-
fining), for absorbing liquids from gases (gas-
oline from natural gas), and as a source of
industrial gases. Some lignite deposits yield
montan wax. In the United States only small
deposits in Arkansas and California yield
enough such wax for commercial workability.
The lone, Calif., deposit is worked for this pur-
pose on a limited scale. Wax is extracted with
solvents and used in polishes, rubber, insula-
tion, inks, greases, coatings, adhesives, explo-

sives, textiles, carbon paper, and hardened
wood.
Lignite, like all low-rank coals, can be gasi-
fied relatively easily and is thus a potential
source of synthesis or water gases, which con-
tain as their major active constituents hydro-
gen and carbon monoxide. Such gas is used for
the production of ammonia (fertilizer), metha-
nol and other alcohols, solvents, synthetic
liquid fuels, and hydrogen.
Unlike the bituminous coals of the eastern
United States, lignite does not produce coke.
Carbonization yields a relatively soft char,
which is currently used as briquetted fuel in
North Dakota and as activated carbon in Texas.
The char is a rapid-burning fuel.
The principal factors that have retarded the
use of lignite are low B.t.u. values, problems of
degradation and storage, and transportation
costs. The combination of high freight rates
(which provide a limitation to the movement
eastward of North Dakota lignite) and a quality
lower than that of bituminous coal moving into
the upper Midwest markets from Central and
Eastern coal fields has confined the general
market for lignite to a rather restricted area.
Advancements in technology with respect to up-
grading, increased efficiency at the consumer
level, and development of alternatives to ex-
pensive transportation will be very important
to the future of the lignite industry.
Lignite may be dried (from 35 to 40 percent
to about 15 percent water) by high-pressure
steam, yielding a lump fuel with a greatly de-
creased tendency to slack or fall apart with
further moisture removal, or by fluidized dry-
ing in an entrained state. There are now no
steam-drying operations in the United States.
The latter method is used on a pilot plant scale,
as described below.
Industrial exploitation of lignite in the
United States-most deposits are in the Da-
kotas and Montana-has been limited to date,
except locally as a fuel, because of two principal
factors, the abundance of higher rank coals
close to points of usage and a lack of industry
and markets in the area of deposits. However,
active development is in progress in Texas.
The outstanding potential use of lignite is as
upgraded solid and liquid fuels and tar. The
fuel produces electric power for making alumi-
num in Texas, even though that State is an oil-
and natural-gas-producing center. In the first
phase of processing, lignite is crushed to 1/4-inch
pieces or smaller and fed to a drying tower
where a stream of hot gas (derived from the
process itself) carries it upward and causes the
moisture to vaporize and disrupt the pieces of
lignite in about 40 seconds. The moisture con-
tent is thus reduced from 36 percent to 5 percent

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