Full resolution (JPEG) - On this page / på denna sida - Second part - X. Manufacturing Industries. By Å. G. Ekstrand, Ph. D., Chief Engineer, Control Office of the Department of Finance - 8. Manufactures of Stone, Clay, Charcoal, and Peat - Peat Manufacture
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850
x. manufacturing industries of 8wedbn.
Peat has of old been used as fuel for domestic purposes in those districts
where wood is scarce. The peat-mosses are for such purposes worked up into
cut-peat; pieces of peat are cut out by hand, and are then left on the ground
to dry, when the percentage of water decreases to 25—30 (raw moss-peat contains
from 75 up to 90 % of water). The size of the peat pieces varies, but in
order to become well dried they ought not to be larger than 25x15x8
centimeters (10 X G X 3 inches). Besides this method, which is the simplest and
up to 1840 was the one exclusively in use, there are also others, in which the
peat, prior to the moulding, is crushed with addition of water into a thick pulp,
which is subsequently carted out on the drying-grounds and moulded by means
of a grate or else simply by means of an iron-scratch. This so-called c rusk té
peat has the advantages, partly of becoming more uniform, inasmuch as different
layers of peat in the moss can thus be mixed together, partly of more easily
getting dried in changeable weather. A third way of preparing peat produces
the so-called tubular peat. In this, the peat is also crushed, but without the
addition of water, and is afterwards moulded into tubular strings, which are left
to dry on racks.
Nowadays the making of peat is also carried on upon a large scale for sale.
Crushed peat as well as machine-made peat or compressed peat is made for the
purpose. In the manufacture of the former, the peat is worked in a horizontal
semi-circular wooden box, in the middle line of which is fixed an iron or wooden
shaft, furnished with obliquely projecting iron blades; this shaft is also connected
with a small pump, which carries water into the box. The shaft, furnished with
blades, is put in rotation through a horse-gear-, portable engine-, or petroleum
motor. In the preparation of compressed peat the different layers of peat are
first dug out and well mixed, after which the peat is moulded, without adding
water, into bricks in a machine resembling a brick-press. The percentage of water
in compressed peat is reduced to 22.
Attempts have been made to refine peat so as to produce from it a more
concentrated form of fuel, partly as peat-coal, and partly as powdered peat. The
manufacture of bricklets does not now meet with any technical obstacles, and the
bricklets get the same specific gravity as fossil coal, or even become somewhat
heavier. But the heating capacity of the bricklets is but slightly greater than
that of ordinary machine-made peat, while the cost of production becomes about
twice as high. Peat-coal seemed at first to promise well, but no fully satisfactory
method for its production at a remunerative rate has yet been discovered. Where
it would be desirable to use peat in the form of charcoal, for instance in
blastfurnaces, burning the peat in an ordinary charcoal kiln would seem to be the best
method in this country, inasmuch as that does not involve any expensive plant.
— Peat-coal not made into bricklets, is certainly heavier than charcoal, but it is
more than twice as voluminous as fossil coal, although per weight it possesaes
about the same heating capacity.
Powdered peat is a new product, obtained by air-drying the peat until it
contains 40—45 % of water, after which the rest of the water evaporates by
kiln-drying. With some varieties of peat it is possible, subsequent to drying,
to remove the fibrous part of the peat, which is suitable for use as a textile
substance; this naturally reduces the final cost of production of the powdered peat.
Powdered peat fed into an oven where a flame has been kindled, ignites at onee
and produces a very considerable heat which lasts a long time. Should the financial
side of the production prove favourable, there is every reason to suppose that this
form of fuel will be very extensively employed. As fuel, peat has in general up
to date occupied but a very subordinate position in comparison with wood and
fossil coal. It seems, though, as if gradually a change will take place in this
respect. In 1901 there were in Sweden 27 peat factories, with a production
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