THE COLLIERY GUARDIAN

AND

JOURNAL OF THE COAL AND IRON TRADES.

Vol. CXV.

FRIDAY, APRIL 5, 1918.

No. 2988.

COAL AND SHIPPING. I r” *"TT

XXVI.-Patent Fuel.

In the British Isles coal briquetting is mostly confined
to South Wales, where it is generally known as the
patent fuel industry. The industry is closely associated
with shipping, as the bulk of the production is export: d,
and it may be stated that both the manufacture and
the export of coal briquettes are destined to increase
considerably on account of their economic advantages.
The industry was commenced in South Wales in 1850,
its principal object being the disposal of some of the
coal slack accumulated at the collieries. This question
of the disposal of small coal has become one of national
importance, not only from the economic point of view,
but also on account of the disorganisation in the

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Fig. 1.—Stacking Briquettes in

the Hold of a Vessel.

in the practice adopted in the successive stages of the
process—for example: the degree of fineness to which
the coal is ground; the moisture content; the per-
centage of binder used; the mixing and heating of the
coal and binder; the method of applying and extent of
the pressure— all have an important bearing on the
quality of the briquettes produced.

The process of briquetting, briefly described, consists
of measuring and mixing the coal and binder, grinding,
heating and kneading into a plastic mass, and finally
compressing. The binding medium has been the object
of close investigation and experiment, with a view to
obtaining a substance possessing not only cohesive



product—disintegration in burning, low heating value,
excessive ash and smoke, etc.

Briquettes manufactured with high grade fine coal, in
a factory possessing an up-to-date equipment, and under
skilful supervision, are, however, equal to first class large
coal. Furthermore, the manufacture of briquettes offers
opportunities for the production of a fuel to a definite
specification, by blending small coals of different
properties ; and the writer predicts a great future in
this direction for the coal briquetting industry. For
example—if a highly volatile fine coal is mixed with slack
of an anthracitic nature in the correct proportion, the
advantages of both are secured without the objection-
able features of either when used alone. In this con-
nection it should be remembered that fine coal gives
much the same analysis as the large from which it is
reduced, the crux being its imperfect combustion in the
fine state, but if compressed, with a binder, into a compact
block of suitable size, satisfactory results are obtained.

Patent fuel of first quality possesses advantages in
view of uniformity of shape, even combustion with a mini-
mum of smoke, caking or clinkering, and without disin-
tegration, whilst the heating value should be about equal
to that of a high-class coal. The breakage in transport
is less than in the case of large coal, and as regards
storage, briquettes possess considerable advantages,
since they can be evenly stacked, occupy less space for
equal tonnage, do not deteriorate and are not liable to
spontaneous ignition. A large size has advantages
for storage, but small briquettes and ovoids or rounds
are better as regards combustion. The briquettes manu-
factured in South Wales very in size from 9 in. x 5 in.
X 3 in., weighing 9 lb., to about 12 in. x 8i in. x 5 in.,
weighing 26 lb., and these are the kinds we have under
consideration from the point of view of shipment.

So far as the analysis of patent fuel is concerned, this
depends on the composition of the coal used and the
proportion of the mixture, so that the ash content may
vary from about 5 per cent, to 10 per cent, or more,
moisture from about 1 per cent, to 2J per cent., sulphur
from about 0'65 per cent, to 0’95 per cent., volatile content
from about 10 per cent, to 17 per cent., whilst the
heating value will vary from about 12,000 B.T.U. to
as high as 14,500 B.T.U.

Shipping' Briquettes.

Several of the patent fuel works—situated at Cardiff,
Port Talbot, Newport, and Swansea—adjoin the docks,
and have their own gantries from which the briquettes
are shipped, by cranes on the quay, direct into vessels
alongside. One method is for the briquettes to be loaded

working of the collieries and in transport, the excessive
accumulation of small coal in the wagons which remain
on the colliery sidings causing wagon shortage and
railway obstruction. In this connection it must be
remembered that, at many collieries, after the coal is
brought to the surface and passed over the screens,
about 40 to 50 per cent, of small remains. Thus, the
extent of the accumulation of small coal depends on the
demand for large; whilst the markets for the former
are considerably less than for the latter. This small
coal is only that brought to the surface, but if, in
addition, the great quantities of small which are not
brought to the surface at all be considered, it will be
realised that there are great opportunities for economies
to be effected in the profitable utilisation of coal, in
which connection briquetting is an important factor.
The question of the treatment of small coal to improve
its condition for use is also worthy of greater attention,
and it may be allowed that, by the processes of screening
and washing the small, about 25 per cent, to 30 per
cent, of nut size is obtained—which can readily be
disposed of, and 55 per cent, to 60 per cent, of smaller
grades, including the fine or duff; whilst the shale or
waste extracted by washing amounts to about 15 per
cent. Small coal can thus be utilised to best advantage
by washing, which reduces the ash content or waste.

Manufacture of Briquettes.

Proceeding to the subject of briquetting, although
the industry in South Wales was commenced about
70 years ago and has been fairly established there about
50 years, it is surprising to note that there are not more
than about nine or ten companies at present in opera-
tion, with a combined output of only about 2 million
tons per annum. This slow rate of development must
be attributed to the extent and quality of our coal
resources having resulted in neglect of economic
principles. The patent fuel factories in South Wales
are established at the docks, or near by, on account of
shipping facilities, and it may be mentioned that the
screenings from the tips during shipment are also
utilised at the factories for briquetting. The small coal
used for patent fuel is at present washed by only two
or three of the companies referred to; but washing,
although it adds to the cost, greatly improves the
quality of briquettes and reduces the ash content con-
siderably; the practice is therefore being extended, as
the advantages are becoming appreciated. Although
the process of briquetting coal is not a complicated one,
it is a technical industry and the product may vary
considerably. This is due not only to the difference in
the analysis of the coal used, but also to the difference

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Fig. 2.—Portable Elevator for

Loading Wagons or Stacking.

properties, but the absence of features deleterious to the
fuel. The binder in almost universal use is coal tar pitch,
and the proportion varies from about 6 per cent, to 10
per cent., depending upon the analysis of the coal used
and the details of the process of manufacture. As
regards the coal used, briquettes have not even yet
overcome the prejudice which their very name intro-
duces to those not familiar with the qualities of the
present-day product of South Wales. This is doubtless
attributable to the indiscriminate selection of the coal
slack, and to absence of knowledge or reasonable care
in their manufacture, in the past, resulting in an inferior

on to trays at the works and conveyed on trolleys along
rail tracks extending the length of the gantry. The
chain slings are attached to the hoisting rope of the
crane and lowered into the bold of the vessel, and there
the briquettes are stacked. Fig. 1 illustrates stacking
in the hold of a vessel. The equipment frequently used
for shipment consists of four sets of slings, 16 trays,
eight trolleys, and eight sets of rails. These rails are
set to the gauge of the trolley wheels and are used in
the ship’s hold for conveying the loaded and empty
trolleys to, and from, the bottom of the hatchway-—where
they are deposited by the crane—to the different part