220

THE COLLIERY GUARDIAN.

February 4, 1916.

CURRENT SCIENCE

Peat as a Source of Fuel Oil.

Mr. W. H. Helm,, in, the Journal of the Royal Society
of Arts, says that the, value of peat deposits as a source
of fuel,has been in part known for hundreds of years;
but up .to recent year.s it has been unrecognised, even by
men of science, that the greater part of that value was
wasted, namely, the oil that can be produced from this
material. ; Not only is it nil-producing, but the oil which
can be, .and is now being, distilled from common peat
is one of the finest and purest oils that can be obtained
for burning in quantities sufficient for any practical pur-
pose. By the scientific treatment of peat, waste has now
been almost completely abolished, and the peat is con-
verted into charcoal, ammonia, acetic acid, acetone, and
methylic alcohol, as well as a gas which is used, with-
out other fuel, to heat the retorts in which the distilla-
tion of peat is carried out.

The charcoal which remains as the solid residuum,
after the distillation of the peat, is of special value, in that
it is not only of great heating power, but contains very
little sulphur, and the oil produced in the chemical
breaking up of the peat is one of the specific results of
the process. On further distillation this oil is itself sub-
divided into light oil, fuel oil, paraffin wax, phenols, and
pitch. The light oil is useful for internal combustion
engines; the paraffin wax can be used for any purposes in
which good paraffin wax is generally employed; the pitch
is just pitch, and is no more or less useful than other
pitches. But the really notable resultant is the fuel oil.
This is produced of a quality to meet the specification
of the British Admiralty for naval fuel oil; and it has
the immense advantage of being practically devoid of
sulphur.

The absence of sulphur in a fuel oil eminently suit-
able for naval engines is of immense importance to the
health and comfort , of the engineers and firemen in all
cases, and of the whole crews in the case of destroyers
and torpedo boats. The misery produced by the fumes
emitted from the furnaces when the fuel contains an
appreciable proportion of sulphur may readily be
imagined by anyone who has himself burned sulphur in
a room or store for the destruction of moth, and has
opened the door to see how the stuff was burning. The
lungs are suffocated, the eyes are inflamed by this
penetrating smoke, and the human victim feels for a
time, that he would rather all the germs and moths
should do their worst than that he should suffer such
intense discomfort. Yet the stoker in the engine room
of a ship where sulphurous fuel is burnt—as it commonly
is in small, swift-going naval craft—has to endure a
similar discomfort nearly all the time, and this discom-
fort is often shared by half the crew who happen, to be
employed below deck, particularly in the space behind
the engines. Not only does the health and efficiency of
the human factor suffer much from sulphurous fumes
from the oils hitherto in use in our Fleet, but the
mechanical factor, the engines themselves, suffer a con-
stant deterioration from the same cause. For every
reason it is desirable that the oil containing the minimum
of sulphur should be employed.

For naval purposes, therefore, not only on the score of
efficiency as a fuel, but of economy of health and
humanity, the peat oil is ideal. As to cost, the price at
which it is being already produced is satisfactory, and
the price at which it will be produced when large sup-
plies are demanded, and great quantities of peat are
brought under treatment, will be considerably less than
it is in the present circumstances of restricted manu-
facture.

The supply of the raw material is practically inex-
haustible. It is true that, in spite of the fact that the
neglect of all but the surface'peat has, up till recently,
left the lower masses to become richer year by year in
those constituents from which oil is now being produced,
there has been appalling waste during centuries past;
but there should be waste no longer. The peat moors
of Scotland, of Northern England, of Ireland and Wales,
and of France, where vast tracts of peat lie about La
Vendee, for instance, and in other regions well known to
specialists in the new process, will almost certainly be
brought under the control of men who will know how to
develop to the utmost for national purposes these rich
gifts of Nature hitherto so lavishly misused.

Working Depths of Our Mines.

Mr. G. H. Askew (Chambers's Journal), in dealing
with this question, refers to the borehole sunk at
Schladebach, about 15 miles from Leipzig; perhaps the
deepest bore that has ever been made. The bore was
undertaken in making a search for coal, and was
1 mile 117 yds. deep, commencing with a diameter of
6 in. and finishing at a little more than 4 in. The col-
lective weight of the working system of rods was about
20 tons, and not less than 10 hours’ hard work was
necessary before the crown was raised from the bottom
of the hole to the surface. The geological results thus
obtained of this exploration of the earth’s crust were
of very great interest to geologists; but it also gave more
full: and definite information about the internal heat of
the.earth than had ever been obtained by any previous
experiment. ’ Capt. Huysson, the German engineer who
bored this hole, took the temperatures at the various
depths with an arrangement by which ho could place
temporary plugs in the hole at any depth desired. He
then determined the temperature of the water (with
which the hole was filled) in a short length so plugged
above and below that, the circulation was. stopped, and
the water thus confined might be relied upon to, indicate
the temperature of the strata which held it'. These
measurements were taken at about every 100 ft.—in all
there were 58 recorded—so that the. measurements
should truly indicate the varying temperatures. The
readings proved that there was an increase of 1 deg. for
every 66 ft., starting from a depth of 100 ft. down to

AND TECHNOLOGY.

1^ mile, and that the temperature of the rocks.all over
the earth at'a depth, of 1 mile is 132degs., and conse-
quently, at a depth of 2 miles, 212 degs. or the tempera-
ture of boiling water. .If this be correct, any water in
a pit at this depth will be practically at boiling point,
and will give off large quantities of vapour, which will
not only keep the roads from being dry and dusty, but
will act very deleteriously on the roof, sides, and floor;
and, combined with the heavy pressures, will make it
extremely difficult to support and maintain the road-
ways. Even if dry heat'be encountered, a coal mine
would be a veritable powder magazine with both coal
and rocks so heated that they could not be touched
without scorching the flesh! Moreover, the atmospheric
pressure at this depth would be equal to an increase of
850 lb. per sq. ft. on all exposed surfaces. In these circum-
stances, mining operations at a depth of 2 miles would be
distinctly unpleasant. This practical proving of the condi-
tion of the earth’s interior leads to the conclusion that
oven if the difficulties of the heat in mines of a depth of
2 miles could be overcome, the heavy pressures exerted
on the rocks and minerals by those superimposed would
render is practically impossible to work seams of coal
successfully and safely.

Multi-core Cables.

In the construction of multi-core electric cables of one
type or another, it is often desirable to employ some
means of easily distinguishing core from core, or pair
'from pair. The most general methods are by the use
of coloured cotton lappings, and coloured tapes of paper
or cotton. Cotton lappings are mainly used on tele-
phone cables, in which unvulcanised rubber, silk and
co. ton form the insulation. The number of cores in
such cables may run into hundreds, and it would be
scarcely possible to make the cores distinguishable with-
out the use of coloured cotton, in single or “ self ”
colours, in double, or in triple-colour combinations. In
the case of “ pair ” cables, one colour is used
throughout on one core of each pair, and combinations
of two or three colours on ;he other core. Occasionally
also, in lieu of coloured tapes, cotton lapping is used on
the cores of small vulcanised rubber multi-cores, over
the grey tape. Generally, however, coloured proof tapes
are used on vulcanised rubber multi-cores for dis-
tinguishing purposes, and usually on bitumen cables,
though some makers omit tape from the cores of the
latter class. If the single colours available are insuffi-
cient, two are put on in parallel, each half the width
of the ordinary single colour tape, thus producing a
spiral striped effect. The use of coloured papers is
confined to paper insulated power cables, and dry cores;
in the latter case, sometimes accompanied by a whipping
of cotton. The range of colours is necessarily more
restricted than in the case of cotton, and the number of
combinations of colours is correspondingly less. Also
where two colours are used, they are put on in succeed-
ing layers, and not in parallel strips as in the case of
cotton tapes. In considering two- or three-colour com-
binations, it is found that the number of cores which
can be coloured with single and two-colour combinations
is equal to the sum of the numbers of the colours. That
is, where three colours are used (1 + 2 + 3) cores can
be coloured; or where N is the number of colours used,
| N (N + 1) cores may be coloured by the use of N
single colours, and all possible combinations of two
colours obtainable therefrom. Thus, eight colours will
give 4 (8 + 1) or 36 cores, made up of eight cores with
one colour, and 28 cores with two-colour combinations.
The numbers of combinations made by the use of three
colours are rather more difficult to find by formula. On
working out several examples, however, it is found that
they are expressed in an irregular progression of the
terms :

1; 1 + (1 + 2) ; I + (1 + 2) + (1 + 2 + 3) ; etc
—Electrical Review.

Estimation of Carbon Dioxide in Air by Haldane’s Apparatus.

In discussing this question before the Society of
Chemical Industry, Mr. R. C. Frederick stated that, for
the estimation of small quantities of carbon dioxide in
air, this is the most convenient apparatus to use, and in
skilled hands it is a quick and sufficiently accurate
method. The principle is that the C02 is absorbed by
caustic potash, and the consequent diminution in
volume, being measured on the graduated scale, gives a
direct reading of the quantity present per 10,000 parts of
air. If the potash solution is coloured with methyl
orange, movements of the liquid are made more
apparent. Stress is laid on the importance of agitating
the water in the water jacket, and considerable effort is
avoided if a blowing bulb is used to provide the air
current instead of ■blowing by mouth. A full and
detailed account of the manipulation of the apparatus
was given, both when employed direct in the space to bo
tested and when used for the testing of air samples. In
the latter case a mercury bath is required. The sample
bottles are 2oz., narrow mouth stoppered, and the
sample is collected by placing a rubber tube in the bottle
and drawing a deep breath through the tube. Improve-
ments were suggested, consisting in the use of a gradu-
ated tube enabling the amount of CO2 to bo estimated
up to 500 parts per 10,000, the usual limit being 100;
and a balance arrangement to lessen the labour of lower-
ing and raising the mercury. This was worth doing
when as many as 200 tests per diem had to be performed.
It also kept the mercury from being put too high or too
low. Mr. Bray pointed out that delicate manipulation
was necessary to keep the mercury from being thrown’
.into the potash or vice versa, and the second suggestion'
was useful in this respect.' He also pointed’ out that the
practice of blowing into the water bath with the mouth
was objectionable, as it was liable1 to raise the tempera-
ture. A rubber pressure bulb, on the other hand,

introduced unsaturated air and reduced the temperature.
It was better that any air that must be introduced should
first be bubbled through water. Dr. S. Rideal said that
the suggestions might be applied to other apparatus
besides . Haldane’s. The'second one would be useful
whenever a mercury bulb was employed. Mr. J. G.
Butterfield doubted the accuracy of the method for
estimating above 100 parts per 10,000, ■ because the
graduated1 tube would be outside the water jacket. An
assistant of his had devised a balance somewhat similar
to that shown. In introducing air it could be blown
through a kind of Wolff’s bottle; but the effect on
temperature was not important, as the essence of the
Haldane apparatus was that it was not affected by
changes of temperature. Mr. Frederick, replying, said
that his small graduated tube had been tested alongside
Dr. Haldane’s large apparatus, and had given identical
results. The blowing of air through the water jacket
was often very important. In the latter types of
apparatus, the bulb was lower down in the water, and
blowing was not necessary.

THE UTILISATION OF ENERGY
FROM COAL.*

POSSIBLE ECONOMIES IN POWER PRODUCTION.

By Prof. W. A. Bone, D.Sc, Pli.D., F.B.S.

Of all directions in which we may look for the
achievement of further greav, economies in coal con-
sumption, probably none are more promising than those
of power production on a large scale.

Coal which is intended to be used for power and
heating purposes should be sold in this country, as it
is in America, on a calorific basis.

We shall not be far wrong in assuming for our present
purposes that the heat equivalent of the available energy
in 11b. of an average coal is 13,000 British thermal
units. And, inasmuch as the heat equivalent of a horse-
power hour is 2,561 British thermal units, it follows
that were we able by any means to transform .he avail-
able energy in coal into mechanical power without loss
of any kind, we should obtain a horse-power hour output
of work by the expenditure of about 0 2 (one-fifth) lb. of
coal.

Now, according to Mr. Beilby’s estimate, 52 million
tons of coal were consumed for power purposes in the
United Kingdom during the year 1903, and the average
consumption per horse-power hour was no less than
about 51b. This means -that we were then only con-
verting on an average about 4 per cent, of the available
energy of the coal burnt into useful work, the other
96 per cent, was wasted.

We may convert the energy of coal into mechanical
work either by raising steam in a boiler or by gasifying
the coal completely in some form of gas producer. Both
methods are imperfect. In the first place, the thermal
efficiency of a good modern type of coal-fired boiler is
not far short of that of the gasification of coal in a gas
producer, and may be put at about 75 per cent.

Now, under favourable working conditions, a gas
engine will convert about 27 per cent, of the energy
of the gas supplied into available horse-power, so that
the coal consumption required to obtain a shaft horse-
power hour by means of the combination of an efficient
gas producer and a gas engine need not be more than
11b.

In the year 1903, to which Mr. Beilby’s estimate
applied, the best gas systems in operation did not require
—when working at full load for 12 hours a day for six
days a week—a consumption of coal at the producer of
more than about lib. per brake horse-power; hence it
would appear that about four-fifths of the 52 million
tons of coal burnt that year for power purposes might
possibly have been saved, had the most efficient gas
systems been universally employed and worked at
nearly full load under the most favourable conditions.

Since 1903, however, great advances have been made
■in the development of the steam turbine, and according
>o the published res Lilts of trials on the new 35,000
horse-power Parsons turbo-alternator erected at Fisk-
stroet Power Station in Chicago, the fuel consumption
"/t so large a turbine steam set (assuming a boiler
efficiency of 75 per cent.) has now been reduced to 1 lb.
of coal per horse-power hour,-,- so that there is now pro-
bably little to choose between the thermal efficiencies of
the best types of steam and gas systems, each working
under the most favourable conditions. No doubt the
position has improved on the whole since the year 1903,
and until definite data arc available for 1913, it is
difficult to say what is the possible margin of fuel
economy in power production to-day, but it is probabiv
not less than 20 million tons per annum, and may le
considerably more.

Broadly speaking, the solution of the power problem
involves several separate considerations. First of all, of
course, there is the question of the relative thermal
efficiencies of the different systems of converting the
energy of coal into available power. Equally, land some-
times more, important is the further question of the
general planning and organisation of a power scheme in
regard to capital outlay, running costs, and other con-
ditions of a local character. For the question of .lie
ultimate not cost of the power, including cost of fuel,
labour, supervision, interest redemption and deprecia-
tion,. must always be the main and over-ruling
consideration in any given case, and it by no means
follows that the most efficient system from a purelv
thermal point of view will undeiwany given conditions
necessarily be the cheapest in the long run.

Bearing this in mind, I may now point out certain
■considerations relative to the rival claims of gas ano
‘ steam systems, in respect of the fuel problem at the
.; * From a lecture (No. 3) at the Royal Institution of Great
’Britain. .	.

f See Engineering, November 12, 1915.