January 21, 1916.

THE COLLIERY GUARDIAN

123

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the gaseous products yielded by the decomposition of
anthracitic, semi-bituminous, and bituminous coals at
definite temperatures between 450 degs. and 1,100 degs.
Cent., and have established (1) that at low temperatures
(up to 500 degs.) the gaseous products are chiefly
methane and the higher paraffin hydrocarbons, whilst
hydrogen is evolved in comparatively small quantities;
(2) 'that the evolution of paraffins entirely ceases at about
700 degs. Cent., the absolute amount of methane reach-
ing a maximum at between 900 degs.; and (3) that
between 700 degs. and 800 degs. there is a critical point
above which evolution of the 'hydrogen abruptly and
rapidly increases.

Such results suggest the existence of at least two
distinct types of organic compounds in coals, namely :
(1) Compounds of low stability, which readily decompose
at temperatures between 400 and 700 degs., yielding,
primarily, paraffin hydrocarbons and methane, but com-
paratively little hydrogen; and (2) a more stable type
which does not decompose until the temperature exceeds
700 degs., when it yields mainly hydrogen. All coals
of carboniferous origin (i.e., ordinary bituminous coals
and anthracite) contain these two types of constituents,
and it may prove that the difference between the various
classes of bituminous coals is largely due to variations
in relative proportions of the two types of compounds
which they contain. Also, it seems probable that the least
stable type of compounds, whose decomposition is mainly
responsible for the smoke produced when a fresh charge
of fuel is added to a fire, have been derived from the
resinous constituents of the original vegetable debris,
whilst the more stable (or humic) type, whose com-
bustion is smokeless, represent the degradation products
of the original cellulose.

A separation of the two types of constituents may be
effected by means of certain organic solvents. Some
years ago Prof. P. Bedson, of Newcastle-on-Tyne, called
attention to the remarkable solvent action of pyridine
upon coal, and showed that if the coal be finely ground
so as to run through a sieve of 1,000 apertures per square
inch, then mixed with sand and extracted with the
solvent in a Soxhlet apparatus, a large proportion of
the resinous constituents pass into solution. On
evaporation of the solvent there remains a resinous
residue which, as Dr. Wheeler has shown, is partly
soluble and partly insoluble in chloroform. Thus it
would appear that the coal substance may be divided '
into three parts, namely, a portion insoluble in pyridine;
(1) another portion soluble in pyridine, but insoluble in
chloroform; and (3) a third portion soluble in both
pyridine and chloroform. There is little doubt but that
whilst (3) represents the true “ resinous ” constituents,
(1) represents the more stable “ humic ” bodies, result-
ing from the degradation of cellulose. The precise
nature of the intermediate second class is perhaps a
little doubtful, and can only be cleared up by further
research.

It has also been established that the resinous con-
stituents, besides being relatively unstable, readily
absorb oxygen at comparatively low (temperatures, and
that their extraction deprives the coal of its coking
properties. Moreover, inasmuch as the coking pro-
perties of a strongly coking coal are known to diminish
on prolonged exposure to atmospheric influences, it is
fairly clear that the causes of intumescence and coking
in certain classes of coal are to be attributed to the
presence of the unstable resinous constituents, which on
decomposition yield paraffins and a pitchy cement, which
acts as a binding material upon the residual humic
bodies, and so plays a principal role in the ultimate
formation of coke. It is also understandable why an
oxidised coal seam is either non-coking or only feebly
so.

Nitrogen in Coal.

Nitrogen, although present in coals to an extent of
usually between 0-5 and 1-5, and, at most, 2 per cent.,
is a constituent of great economic value, inasmuch as
it is the source of over 90 per pent, of the world’s output
of ammonium salts.

According to the researches of Carrick-Anderson and
Roberts, Hilgenstock, Christie, and others, the evolution
of ammonia when coal is distilled, which begins at
almost 330 degs. in the case of a gas coal, and at 450 to
480 degs. in the case of anthracites (the older in
geological age the higher the temperature), reaches a
maximum between 500 and 700 degs., and ceases alto-
gether at about 900 degs. This ammonia probably arises
from the decomposition of organic compounds probably
of an imino type, which are normally present in small
amounts in all classes of coal.

A very large proportion of the nitrogen, however,
remains behind in the carbonaceous residue in coke,
from which it is expelled as gaseous nitrogen as the
temperature is raised from 900 to 1,900 degs. Hence, it
would seem that nitrogen exists in two forms in coal,
namely : (1) as compounds of an imino type, which
decompose below 900 degs., yielding ammonia; and (2)
in a much more stable “ nitride ” form.

In the actual distillation of coal on a large scale,
whether in gas works or in by-product coking ovens where
ammonia recovery is carried out, it rarely happens that
the yield of ammonium sulphate exceeds 30 lb. per ton of
coal, even though the latter may contain as much as
1-5 per cent, of nitrogen; such a yield corresponds to
about 20 per cent, of the total nitrogen content of the
coal.

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THE UTILISATION OF ENERGY

FROM COAL.*

By Prof. William A. Bone, D.Sc., Ph.D., F.R.S.

The question of fuel economy and the proper utilisa-
tion of coal is, at the present juncture, of the greatest
national importance, not only in regard to the actual
prosecution of the war, but also, and even more so, in
view of the trying years of economic recuperation and
re-adjustment that will follow hard upon its termina-
tion, because, of all directions in which national economy
can be most healthfully and advantageously exercised,
this is perhaps the most obvious and prolific. For it is
tolerably certain that, with an efficient and systematic
public supervision and control of fuel consumptions, we
ought to be able, even with existing appliances, to save
many millions of pounds of our annual coal bill, and,
with improved method and organisation, even more.

The British Association has recently taken up the
matter by appointing a strong committee to consider the
whole question from a national standpoint, and to report
upon the chief direction in which large economies can
be effected, and the best means by which the community
can ensure their realisation. The community has the
right to insist on the proper and most economical utili-
sation of its coal supplies, both in its own present
interests and those of future generations, and that, if
need be, the Government should be called upon to take
such action as will check the most. flagrant cases of
wastefulness and abuse.

Such a suggestion will perhaps be objected to, in some
quarters, on the ground that the operation of progres-
sively higher prices of fuel will in itself be the surest
and most potent compelling force in the direction of
fuel economy in manufacturing operations; and undoubt-
edly there is something to be said for such a view; for,
in the long run, it is the cumulative effect of the daily
cost sheet which impels the commercial mind to seek
further economies. Also, it must be admitted that
some of the foremost manufacturing concerns have
already achieved great results in economy of fuel, and
may he held up as shining examples of what can be
done by the rigid and systematic application of scientific
principles to the heat balance-sheet of a large industrial
establishment. But the problem will never be solved
from a national standpoint by the policy of leaving it to
the slow operation of isolated and independent investi-
gations ; what is needed is a patriotic exchange and pool-
ing of experience, a willingness to co-operate whole-
heartedly and effectively, under skilled guidance and
advice, for a national benefit; and this cannot be
achieved except on the basis of some national organisa-
tion.

The Value of Coal other than as Fuel.

Not only is coal of prime importance as a fuel, but
when suitably handled by the chemist it yields very
valuable by-products. Thus, from the tar and other
condensible products of its distillation are obtained the
raw materials for the manufacture of synthetic dyes;
and, moreover, certain coal distillation products—
toluene in particular—form the basis of the new high
explosives which are now being used in such large
quantities. For years before the war German techno-
logists had already paved the way for the military use
of T.N.T. by ensuring a maximum supply of raw
materials from German coal by the substitution through-
out Germany of modern by-product recovery coking
plants for the old wasteful beehive ovens; whereas we
were still, at the outbreak of the war, carbonising about

million tons of coal per annum in the beehive, ovens
—a state of affairs which is deplorable from every point
of view, showing as it does how negligent and short-
sighted we are of national interests in exploiting the
most important of all our raw materials.

Another notable by-product obtainable from coal is
ammonia, in the form usually of sulphate, which is
chiefly valuable in agriculture as a fertiliser. Indeed,
the world depends upon the nitrogen in coal for about
90 per cent, of its ammonium compounds. Thus, in
1912, of the total British production of 379,000 tons of
ammonium salts, no less than 318,000 tons were derived
from coal. Here, again, we compare unfavourably with
Germany, which in ‘ the same year produced nearly
500,000 tons of ammonium salts from a much smaller
total output of coal.

After dealing with the origin of coal, the lecturer
passed on to its chemical composition and classification
according to Gruner, all of which were discussed at
length.

Coking Properties.

It is important to observe that as a rule the coking
properties of >a coal, as w’-ell as the strength and density
of a coke produced by carbonising it at a high tempera-
ture, vary inversely with the- yield of “ volatiles ” until
they attain a maximum with 20 to 30 per cent, of	__________________________

volatiles, after which they rapidly diminish. Non-caking
coals are principally either (1) those of greatest geological
age, rich in carbon, with correspondingly low hydrogen
and oxygen contents (semi-bituminous, anthracitic or
anthracite); (2) those of more recent origin with a high
oxygen content; or (3) those from “ oxidised ” seams,
which at some period subsequent to the formation of
the coal field had become exposed to atmospheric influ-
ences (e.g., Warwickshire and Leicestershire seams).

When,’however, it comes to the consideration of the
real nature of the various chemical compounds contained
in coal, a lamentable state of ignorance must be
confessed.

Perhaps the most suggestive of recent chemical
researches upon coal are those which Dr. R. V. Wheeler
and his co-workers have carried out at the Home Office
Experimental Station at Eskmeals, in Cumberland, as
part of the larger enquiry on coal dust explosions in
mines. They have studied very closely the character of

* From a lecture at the Royal Institution of Great Britain,

of the Mond type in a superheated air blast saturated
with steam at 85 degs. Cent. By such means, as much
as 80 to 901b. of ammonium sulphate may be recovered
per ton of a suitable coal, together with about 150,000
cu. ft. of a gas containing approximately :—

CO2 = 17-0, CO = 11-0, H2 = 24-0, CH4 = 3-0, N2 = 45-0.
And although the capital cost of an ammonia recovery
gas producer plant of the Mond type is large, it is
nevertheless, a most scientific and economic means of
utilising coal for the production of gas for power and
other large scale industrial purposes.

Need of Systematic Research.

Chemically speaking, coal is a substance of great
structural complexity, and we hardly know anything at
all about either the precise nature of its various con-
stituents or their modes of decomposition by heat. . It
is true, of course, that we have gained considerable
experience as to the yields of the various products (solid,
liquid, and gaseous) obtained when bituminous coal is
distilled under given conditions, but as to how they
arise we practically know nothing.

Two things above all are needed as a. basis for the
scientific utilisation of our coal, and the realisation of all
possible economies in regard to fuel consumption. The
first is a systematic investigation of the chemical nature
of coal, which may best be undertaken by a selected
group of experienced chemists .aided by adequate grants
from public research funds; the second is a chemical
survey of the principal British coal fields, which ought
to be organised by some public Department, acting in
conjunction with the laboratories which have been
established for the special study of fuel technology at the
universities and other institutes for advanced research in
applied science. We already have in the country all
the means, as regards men and equipment, for the work,
and it only remains for the authorities who administer
money voted by Parliament for scientific and industrial
research, to provide adequate grants for its effective
prosecution.

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COKE OVEN MANAGERS’ ASSOCIATION.

The first annual dinner of the Coke Oven Managers’
Association was held at the Grand Hotel, Sheffield, on
Saturday, January 15, Mr. George Chrisp (president)
in the chair, and was well attended, about 80 members
and visitors being'present.

In proposing the toast, “ The Coke Oven Managers’
Association,” Prof. W. A. Bone (the guest of the even-
ing) said that the carbonisation industry was playing a
great part in the war, and would become even more
important afterwards. While credit must be given to
German enterprise in the development of the by-product
industry, he believed that the victory of world power
would go to the nation which could combine character
with high scientific advance. Commercial integrity was
higher in England than in any country he knew of; and
if that could be supplemented by high technical
efficiency in the application of scientific principles, Great
Britain and the Empire need have no fear of the future.
The highest form of patriotism was for each man to be
prepared to add to the general stock of knowledge and
experience that which he knew best, and be prepared to
sacrifice to some extent his own interests in so doing.

The President, in replying, said that better oppor-
tunities were needed for the education of the coke oven
manager, who was a blend of chemist and navvy
ganger—qualifications for which no university would
grant a degree. The chief need was the assistance of
scientific associations in solving the problems that faced
the industry, and such collaboration would be highly
welcomed. The status of the coke oven manager at
present was unsatisfactory, Government recognition
being needed.

Lieut. R. H. Montgomery (Ministry of Munitions)
urged the importance of increasing the output of benzol,
for supplying our Allies, as well as ourselves, and said
that the production of coke and all commercial con-
siderations should be subordinated to that end.

Mr. G. Blake Walker suggested the formation of a
committee of reference to consider the practicability of
new ideas put forward by coke oven men. Some of
these ideas might not bear direct fruit, but, just as the
search of alchemists for the transmutation of metals
led up to other chemical discoveries, the exercising of
the mind was always a valuable training. So far as the
body with which he was most closely connected, the
Midland Mining Institute, was concerned, it would
gladly collaborate in the direction mentioned by the
President.

Messrs. T. H. Riley and W. Waite contributed to the
harmony of the evening by a number of songs, and the
proceedings terminated with a vote of thanks to the
President.

The actual distribution of the nitrogen among the
products of the distillation on a large scale is somewhat
as follows :—

Per cent.

As N in coke .................... 40 to 50

As No in gas .................... 20 to 40

As NH3 _____..........................  15	to 20

As organic basis in tar ............	3 to 4

As cyano compounds ..............	1 to 2

In the Central Criminal Court, on Wednesday of last
week, Charles Frobisher, sapper in the Royal Engineers,
pleaded guilty to a charge of uttering a false declaration for
the purpose of obtaining the grant of certificate of qualifica-
tions as surveyor of mines under the Coal Mines Act. In
1914, Frobisher was assistant to an underground surveying
staff at Baywater Collieries, Castleford, Yorkshire; but as
his work was found unsatisfactory, he was given other duties.
He enlisted as a sapper on July 19 last, and obtained forms
to sit for an examination of the Board of Mining Examiners.
He subsequently wrote to the manager of the collieries,
asking him to sign a form testifying to his surveying experi-
ence, but, receiving no reply, he filled in the particulars
himself, and signed the manager’s name to them. About
three weeks before the examination the military authorities
communicated with the Board, and as a result the accused
was arrested. Later, the accused wrote to the Board asking
for a return of the forms, saying he had filled in the
employer’s name in ignorance. Defendant was sentenced
to six months’ hard labour.

A much larger quantity of ammonia may be derived
from the nitrogen in coal by gasifying it in a generator