058

The: colliery guardian

November 17, 1916.

CURRENT SCIENCE

A By-Product Steam Boiler.

Mr. G. Wilkinson, chief electrical engineer to the
Harrogate Corporation, reports (Electrical Engineer)
that, as a result of investigation and experiment in
smokeless combustion, he has been able to design a
boiler furnace, in which the coal is distilled, tar and
ammoniacal liquor being extracted as by-products; the
coke obtained from the coal while incandescent gravi-
tates into the furnace, and is there consumed without
smoke; and the gas, after being denuded of the by-pro-
ducts, is also passed into the furnace under considerable
pressure with the necessary air, and burns with a smoke-
less flame until it enters the retort flue, where it is
transformed into radiant heat. This radiant heat is
absorbed partly by the retort, and partly by the water
in the boiler. Thus, very active steaming surfaces are
produced not only in the furnace, but upon the whole
flue surface. On an average, it is expected to get from
20 to 25 lb. evaporation per sq. ft. of heating surface.
The boiler is automatically fed with coal, which passes
through the various stages of distillation and combus-
tion automatically. It is also’ expected the boiler will
furnish superheated steam by reason of a special arrange-
ment inserted in the boiler itself. Mr. Wilkinson
calculates that twice or three times the amount of steam
produced by the ordinary shell type boilers per sq. ft.
of boiler floor will be furnished by his boiler, whilst,
owing to the smokeless combustion, no chimney stack
will be required, induced draught fans being employed
instead of a chimney stack. Mr. Wilkinson states that
there is no plant at present available for coal distillation
and steam raising at a reasonable price or of convenient
and efficient design. Furthermore, the prevailing idea
that coal distillation and steam production can be
economically carried out successfully on a very large
scale only, will be dispelled when closer attention is
given to the problem, provided the powder station engi-
neer is wise enough to dispose of his crude products to
firms who prepare the various useful commodities there-
from, for which there is a ready and increasing demand.
When this possibility is realised, there will be less fuss
made about “ linking up,” which is the fashionable sub-
ject of the hour, and which is largely based upon the
assumption that super-stations, preferably established
on the coal fields themselves, are alone able to produce
economical results, by-products of coal, and low costs
of production.

Benzol Extraction on Coke Ovens.

In his presidential address to the Western District of
the Scottish Junior Gas Association, Mr. G. T. Purves
dealt with the washing of coal gas for the recovery of
benzol and toluol. He said the tar washing process was
a makeshift method of extraction, justified only by the
urgency of the times, and not worthy to be applied in
fair-sized works after the war requirements were satis-
fied, although it might still be used in small works.
When it left the tar washing plant, the gas would
generally be saturated with naphthalene vapour, and as
it must contain considerably less liquid hydrocarbons,
accentuated trouble from naphthalene deposit might be
expected. This, however, did not apply to the smaller
works where the carbonisation was usually less drastic;
nor probably where continuous vertical retorts were in
use. Oil washing, which was now applied at quite a
number of gas works, as well as at coke works, was the
one process likely to be seriously considered. It was
formerly normal practice, on coking plants, to produce a
65 per cent, light oil, but later 60 per cent., and even
55 per cent, oil was produced. In order to produce the
higher grades of light oil, naphthalene and some of the
higher benzene homologues, which were being carried
away in the vapour from the wash oil still, were thrown
back into the wash oil by partial dephlegmation. In
this wray the naphthalene absorption power of the wash
oil was reduced, while the benzene absorption power was
unimpaired, and so the ratio of naphthalene to con-
densable liquid hydrocarbons in the gas might be
increased by oil washing, with the result that the danger
of naphthalene stoppage in the distribution system
would be accentuated. If this degree of dephlegmation
were avoided, and a lower grade of light oil produced,
the wash oil wnuld be largely denuded of naphthalene,
and so a continued absorption of naphthalene from the
gas could be effected with a probable reduction of the
naphthalene trouble. The light oil contained some 15
to 25 per cent, by volume, and sometimes more, of the
wash oil, and when the light oil was to be sold to a
refiner, it would seem desirable on this account, and also
possibly to avoid too drastic de-benzolising of the gas,
to produce the highest grade of product. In his opinion,
this practice on a gas works would be absolutely wrong,
on account of the influence on the content of naphtha-
lene in the gas. Another aspect of oil washing which
should favourably commend the practice to gas makers
was the removal of carbon disulphide and other organic
compounds containing -sulphur from -the gas. The pre-
sence of about 1 per cent, of carbon disulphide in 90
per cent, benzene, showed to what extent this product
was extracted in oil washing.

From the point of view of benzol recovery, it was
immaterial whether the benzol absorption plant preceded
or followed the purifiers on gas works plants. Where
the gas was to be oil washed for benzols, the gas must
be as free as possible from ammonia, as this gas was
absorbed by the wash oil, and if a considerable amount
was present very serious damage might be done in the
oil heating system. The fact that ammonia was
required in the gas before it entered the purifiers, and
should not be present before benzol scrubbers, indicated
that the latter should follow the purifiers.

He had found that liming the coal might in some cases
increase the yield of ammonia, but not always so. The
experiments of Tervet showed that hydrogen acting on
red-hot coke might play a material part in ammonia

AND TECHNOLOGY.

yield. He (Mr. Purves) endeavoured to get something
like the same effect by wetting the bottom part of the
coal charge to a greater extent than the top. No dis-
tinct increase in yield was, however, obtained, and the
longer carbonisation time was sufficient in itself to con-
demn the practice. Still, he felt that it should be
possible to materially increase the yield of ammonia,
which at the time was about 33 to 34 lb. of sulphate per
ton of dry coal. Next, he determined the best percen-
tage of water to .have in the coal, and this was found to
be about 12|, with a carbonising temperature of 1,050
to 1,080 degs. Cent, on the flame side of the oven walls.
The next point examined was the proportions in which
the ammonia yield was distributed in the gas produced
throughout the carbonising period. Only a few series of
tests were made, but these showed clearly two periods
of increase in ammonia content and two of decrease.
The highest proportion was found towards the end of the
carbonising period, and was undoubtedly largely due to
secondary reactions. The maximum content did not
coincide with the maximum percentage of hydrogen,
because the temperature was then too high. He could
not observe any distinct relationship between the amount
of one particular gas constituent and the yield of
ammonia per ton of coal, but there did appear to be a
relationship between the ammonia and the ratio of
hydrogen to methane. Such a relationship was just
what should be expected, because, in fixing the moisture
content and carbonising temperatures at the optimum
for ammonia production, the rate of decomposition of
the coal had also been fixed, and so a definite ratio of
hydrogen to methane should arise. The ratio in ques-
tion for the one particular coal carbonised was 45
hydrogen to 29 methane, and occurred on the indivi-
dual charge at about the 25th hour in a 35 to 36 hour
carbonising period. At the end of the carbonising
period the temperature of the bulk of the coke was at
least 100 degs. Cent, lower than the temperature of the
flame side of the oven wall—about 900 degs. Cent, or a
little more—and so at the 25th hour this coke mass was
probably only at about 800 degs. Cent. Cobb and
Hollings found that a mixture of equal volumes of
hydrogen and methane suffered a little decomposition at
800degs. Cent., and very marked decomposition at
1,100 degs. Cent. The decomposition of methane
yielded carbon and hydrogen. Burgess and Wheeler
had shown that between 750 and 800 degs. Cent, there
was a large and sudden increase in the quantity of
hydrogen evolved. So between 750 and 850 degs. Cent,
was the ideal condition for the Tervet reaction. The
temperature of the carbonising mass rose rapidly after
about 800 degs. Cent, was reached, and so the time was
short when the conditions were favourable, probably
between the 25th and 27th hour. With regard to the
advantage of using washed or unwashed coal, he had
found no increase in yield of ammonia was obtained by

MANCHESTER GEOLOGICAL AND
MINING SOCIETY.

PRESIDENTIAL ADDRESS.

At the meeting of the Manchester Geological and
Mining Society on Tuesday last, Mr. William Pickup
delivered his presidential address, in the course of which
he dealt at great length with the effect of modern labour
movements and legislation on the economic position of
coal mining. It was not only wise, he said, but essen-
tial in most undertakings or industries—and mining was
no exception—occasionally to review the position as a
whole, to see what were the proper steps to be taken to
meet altered circumstances, and leave the concern at
least in as good a position as it was before. He there-
fore proposed to ask the attention of the members for
a short time to modern labour movements and legis-
lation, and the effects they had had, and were likely to
have, upon the economic position of coal mining. He
proposed to commence the review in 1888, when the
boom conditions of the early ’seventies had been suc-
ceeded by a long period of depression. Up to that time
it was not over-stating the position to say the old
economic law of supply and demand had ruled the
industry with undisputed force. Over-production and
the keenest competition forced prices down to the
lowest point.

Labour Movements.

It was that long period of depression which produced
a discontent with the existing conditions amongst the
miners, and the movement for a “ living wage ” was
first enunciated and commenced. Their leaders imme-
diately realised that to obtain this, “ organisation ” was
necessary. That organisation of labour ” had con-
tinued ever since, and it resulted immediately in the
formation of district unions, later in the federation of
all of them in one association, and, lastly, in the com-
bination of miners, railwaymen, transport, and dock
workers. The demand in those early days for a “ living
wage ” was that, whatever the market conditions were
as to supply and demand, a “ living wage,” agreed
upon from time to time, must first be provided for the
miner; whether or not there was any profit left after
that was entirely the business of the employer. This
new doctrine was almost startling at the time, but the
strength of the demand was such, backed by the organi-
sation which had even then been attained, that in less
than two years 40 per cent, advances in wages upon
the standard of 1888, as follows, had been obtained :—
November 1, 1888.—First advance, 10 per cent, from basis.
July 4, 1889.—Advance of 5 per cent.

October 3, 1889.—Advance of 5 per cent.

January 2, 1890.—Advance of 10 per cent.

March 20, 1890.—Advance of 5 per cent.

July 31, 1890.—Advance of 5 per cent., making 40 per
cent.

Wages remained at that level for two years, when,
on reductions becoming visible, the miners played
Saturdays from April 23 to July 30, 1892, to restrict the
output, and maintained wages at their then level. That
action postponed the evil day 12 months, until August 3,
1893, when the miners’ strike commenced against a
proposed reduction in wages by the employers of 25 per
cent., and lasted 16 weeks, until November 20, 1893,
when work wras resumed, after the Rosebery Conference,
at a reduction of 10 per cent., to 30 per cent, above
basis, but which had not to come into operation for
eight months—not before August 1, 1894.

Conciliation Board Agreements.

A Conciliation Board was also established under this
settlement for the regulation of wages in the future,
which fixed a first minimum at 30 per cent, above the
1888 basis, and a maximum of 45 per cent., and agreed
to regulate wages within these limits for a first period
of two years, from August 1, 1894, to July 31, 1896.
The life of the Conciliation Board was extended from
time to time, with the same minimum and maximum
rates, until December 31, 1900, during which period
wages remained stationary, until October 1898, when
the following advances began and W’ere given :—

October 5, 1896.—Advance of 2J per cent.

April 5, 1899.—Advance of 5 per cent.

October 4, 1899.—Advance of 21 per cent.

January 3, 1900.—Advance of 5 per cent.

October 3, 1900.—Advance of 5 per cent.

The life of the Board was again extended from January 1,
1901, for three yeans, to December 31, 1903, with the
same minimum as before, namely, 30 per cent., but
with the maximum advanced to 60 per cent.; and again
from January 1, 1904, for three years, to December 31,
1906, with the .same maximum of 60 per cent., but with
the minimum advanced to 35 per cent., when advances
were given as follow :—

January 2, 1901.—Advance of 5 per cent.

February 6, 1901.—Advance of 5 per cent., to the maxi-
mum of 60 per cent.

July 2, 1902.—Reduction of 10 per cent.

December 23, 1903.—Reduction of 5 per cent.

August 17, 1904.—Reduction of 5 per cent., to 40 per cent.
After which wages remained stationary for the rest
of the period.

The next agreement -was from January 1, 1907, for
three years, to December 31, 1909, with the maximum
again 60 per cent., but with the minimum further
advanced to 37| per cent., during which period the
following advances took place :—

January 2, 1907.—Advance of 5 per cent.

May 8, 1907.—Advance of 5 per cent.

September 18, 1907.—Advance of 5 per cent.

January 8, 1908.—Advance of 5 per cent., to the maxi-
mum of 60 per cent.

September 16, 1908.—Reduction of 5 per cent.

March 24, 1909.—Reduction of 5 per cent., to 50 per cent.
On September 3, 1909, while wages were at that rate,
the owners applied for a reduction of 5 per cent, below
50 per cent., and were admitted to be entitled to it, but
the owners were asked not to press it, as there was a
danger the men might not accept. To avoid a crisis, it
was agreed that the application should be dropped, that
wages should remain at their then level until all losses
were recouped to the owners through continuing to pay
the 'then rate of wages when a reduction was warranted,
and that the life of the Board should be continued
beyond December 31, 1909, until such time as the
owners should be fully recouped. That arrangement
prolonged the existence of the Board a further three
years, to December 31, 1912, the limits remaining at
37^ per cent, and 60 per cent, as before, w*ages only
being advanced once under it, namely—October 16,
1912, when there was an advance of 5 per cent., to 55
per cent. During that period various subsidiary move-
ments came to a head. Where underground day-wage-
men and boys had not had their wages advanced to the
full extent of 50 per cent, upon the 1888 basis, the
deficiency was conceded; county scales of wages being
agreed to; and in future those classes of workers were
to be subject to the same advances or reductions as
miners. Increased payments for timber drawing, etc.,
were also granted in various districts, and on
December 20, 1912, winders and stokers w*erc brought
i ito line. They had their wages advanced, and a new
county agreement with them was entered into.

In the early part of 1912 the miners, having failed to
obtain a minimum wage rate by legal enactment, moved
to obtain it by their own efforts, and on February 29,
1912, the strike for a minimum wage commenced, last-
ing 5| weeks, to April 7, 1912, when work was resumed,
the Government having in the meantime passed the
Minimum Wage Act, county and local joint com-
mittees being set up thereunder to fix a minimum wage
for all classes of underground workers.

The next Conciliation Board agreement was from
January 1, 1913, for two years and four months, to
April 30, 1915, when the minimum was advanced to 50
per cent., and the maximum to 65 per cent, above 1888,
and between which wages were to be regulated. During
that period the following advances were made :—

January 15, 1913.—Advance of 5 per cent.

April 13, 1913.—Advance of 5 per cent., to the maximum
of 65 per cent.

During that period also, various other subsidiary move-
ments were brought forward. Where surfacemen had
not had their wages advanced to the same extent as
miners, the deficiency was made up, scales of wages
being agreed to in many districts, and in future those
classes of workers were to be subject to the same
advances and reductions as miners. Extra payments
were agreed to in many districts in respect of abnormal
places, and on July 2, 1913, the winders commenced an
eight hours day. On May 1, 1915, the existing Con-
ciliation Board agreement came into force for three
years, to April 30, 1918, under which the men obtained
what they had long desired—the abolition of the old