374

THE COLLIERY GUARDIAN.

August 20, 1915.

CURRENT SCIENCE

Measuring Coke Oven Gas.

In a paper that has just been read before the South
Wales Institute of Engineers, describing the installation
of Coppee ovens installed at Grivegnee, in Belgium,
Mr. P. N. Hambly discusses the method employed of
measuring the volume of the gas generated. Although
the installation is situated in the heart of the industrial
town of Liege, which during this war has gone through
such terrible and glorious times, yet up to a few months
ago the plant had not been seriously damaged.

The determination of the value of the surplus gas
necessitates two distinct operations :—(1) The measuring
of the calorific power; and (2) the measuring of the
total volume. The former can be done by an easy
method upon which the greater number of engineers are
quite agreed (Junker’s calorimeter); but the question of
the determination of the total volume presents difficulties.
The only method which can be called scientifically
correct is that in which a meter is used similar to that
employed at a gas works for measuring gas for lighting
purposes. The coke-oven plant at Grivegnee was erected
for producing the coke necessary for the blastfurnace
belonging to the Societe d’Athus Grivegnee, and is
utilised for manufacturing gas for town lighting
purposes. Therefore two meters were supplied. The
taring of these apparatus is most simple and can be
carried out by placing them in series with a small
portable standard meter. The meters being volumetric
there is no need to maintain the diameter of the pipe-
work nor the volume of gas which is necessary for the
taring of the volumeter based on the Pitot tubes. The
taring was carried out at Grivegnee before the contract
trials, and was found to be exact within J per cent.

Of late years, in order to determine the volume of
gas necessary for heating a battery of coke ovens, and
also the volume of surplus gas, theorists have proposed
an “ indirect method based on the following principles :
—(1) To determine with the help of a calorimeter the
calorific power of the combustible gas; (2) to measure
by an anemometer the volume of air used for combus-
tion ; (3) by chemical analysis to ascertain the
composition of the burnt gases.

This method is nevertheless deceptive, as it substitutes,
for the measurement of the volume of gas, the measure-
ment of the volume of air, and engineers who have had
occasion to make use of the anemometer in mines are
fully acquainted with the difficulties met with in handling
this apparatus; these difficulties, added to those of
taring, make it almost impossible even for a very skilful
operator to obtain more than approximately accurate
results. This is not the least of the imperfections with
this “ indirect ” method, as no battery of ovens possesses
walls, regenerators or flues which are perfectly gas-
tight; no matter how carefully the ovens are built, a
little gas is always passing from the oven chamber to
the oven flues, and it is practically impossible entirely
to prevent some fresh air passing into the regenerators
and flues. Again, the utilisation of a meter gives the
manufacturer the opportunity of checking day by day
the working of his plant.

At Grivegnee the gas is drawn from the gasholder
through three gas boosters, thence through two gas
meters. The gas meters are each capable of measuring
160,000 cu. ft. of gas per hour, and each booster can
force the same quantity of gas per hour to a pressure of
20 to 26 inches of water.

The author describes in detail the contract trials
carried out to verify the guarantees given by the
contractor. In these, by noticing the level of the gas-
holder bell at the beginning and end of the trials and
by observing the index of the meter, it was possible to
determine exactly the volume of surplus gas. In order
to obtain a strict relation between the surplus gas
obtained and the total volume evolved, it was necessary
to measure the gas utilised for heating the battery in
the same way, but the relative disposition of the
apparatus rendered this operation impossible. The
relation between the surplus gas and the total volume
evolved was based on trials obtained in the laboratory
to ascertain the quantity of gas distilled per unit of coal
used, and it was assumed that in practice 95 per cent, of
this was collected in the hydraulic main and taken to
the recovery plant, the remainder representing the
inevitable losses in the atmosphere during the loading
and through the side walls during the period of
carbonisation. The weight of the loaded coal being
known, the total volume of the gas actually distilled
during the trials as well as the relation of this volume
to that of the surplus gas was easily determined.

In order to compare two volumes of gas, it is necessary
that the gases have the same calorific power. Now, it is
quite easy to understand that it. is not possible to obtain
with the same coal, but distilled in two different ways,
the same calorific power in either case. The calorific
power of the gas obtained varies with the depression
produced on its outlet, and is in inverse proportion to
the actual volume distilled. Therefore when distilling
a ton of a similar coal under conditions of suction
slightly different, one can obtain 10,500 cu. ft. of gas at
500 B.T.U. or 11,686 6 cu. ft. of gas at 450 B.T.U. In
either case the product of the two factors, volume and
calorific power, in B.T.U., will be equal to 5,240,000
B.T.U. All results of calorific powers correspond to
the higher calorific power (condensed water not deducted).
The results of the trials are as follow :—

Duration.—From 6 o’clock in the morning of October 22,
1913, to 6 o’clock on October 25.

1.	Preliminary Analysis of the Coal.—Moisture, 5*77
per cent.; ash (on dry coal), 6*93 per cent.; volatile
matter (on dry coal), 2362 per cent.; quantity of gas
evolved per ton of coal at N.T.P., 10,378 cu. ft.; higher
calorific power of 1 cu. ft. of this gas, 549’9 B.T.U.;
total B.T.U. contained in the gas coming from 1 ton of
coal, 5,706,862 B.T.U.

AND TECHNOLOGY.

2.	Determination of the Weight of Coal —Weight of
metallurgical coke produced, 884’326 tons; water
contents, 5’50 per cent.; weight of dry metallurgical
coke, 835’689 tons; weight of small dry coke and ash,
63’242 tons ; total weight of dry coke, 898’942 tons;
total yield in dry coke on dry coal, 78’19 per cent.;
weight of dry coal charged into ovens, 1,149’700 tons;
weight of coal charged per oven per 24 hours, 6’86 tons.

3.	Production of Coke.—Weight of metallurgical coke
at 3 per cent, of water and corresponding to 22 per cent,
of volatile matter in the coal, 880’506 tons; ditto per
24 hours, 293’502 tons; ditto per oven per 24 hours,
5’241 tons.

4.	Measuring of the Surplus Gas.—Gas available
measured at the meter, 7,486,000 cu. ft.; contents of
the gas meter, 141,200 cu. ft.; actual volume produced,
7,627,200 cu. ft.; average temperature of the gas,
18 degs. Cent.; average pressure of the gas, 765’7 mm.;
volume of gas returned at 0 degs. and 760 mm. mercury
pressure (or N.T.P.), 7,234,100 cu. ft.; higher calorific
power of the gas (Junker’s calorimeter), average 72 tests,
486’5 B.T.U.; B.T.U. contained in the surplus gas,
3,521,026,860; B.T.U. contained in the gas corresponding
to the coal charged into ovens on the preliminary
analysis, 6,721,245,765; B.T.U. contained in the total
distilled gas (95 per cent.), 6,385,183,476 ; volume of gas
distilled from the coal at 486’5 B.T.U. and N.T.P.,
11,202 cu. ft.; volume of surplus gas at 486’5 B.T.U.
and N.T.P. per ton of dry coal (measured at the meter),
6,144 cu. ft.; percentage of surplus gas to the total gas
distilled, 55 per cent.; volume of gas at 486’5 B.T.U.
and N.T.P. consumed at the oven per ton of dry coal,
5,026 cu. ft.; volume of gas at 486’5 B.T.U. and N.T.P.
consumed at the oven per ton of dry coal measured at
the volumeter, 4,764 cu. ft.

Coal Fields of British Columbia.

In Memoir 69, forming No. 57 of the Geological Series,
the Department of Mines, Canada, has issued a detailed
account, compiled by Mr. D. B. Dowling, of the coal
fields of British Columbia. These coal fields, as is
known, belong to the cretaceous and tertiary periods.
The coal deposits have been located in a large number
of detached areas, of which no less than 22 belong to
the cretaceous and another 22 to the tertiary age. It is
to be noted also that the earlier coals are by no means
confined to a single horizon in the cretaceous, but are
distributed throughout the lower and upper beds. Thus
the Atlin coal beds are below the Skeena Biver coal beds,
and both these are now held to be older than the
Kootenay formation, to which the well-known Crow’s
Nest coal field belongs. All these are of lower cretaceous
age; while the coals of the Peace River district, Graham
Island, Nanaimo and Comox belong to the upper
cretaceous. The age of the beds is not without economic
significance. Thus the Skeena series and the Kootenay
coal beds far outweigh in commercial importance those
of later date. It is to the Skeena River series that the
Groundhog coal area belongs, and here the name of
Anthracite Creek, and the developments of the British
Columbia Anthracite Company, are indications of a
class of coal differing considerably from that of the
younger coalfields. The tertiary coals are generally
still in the lignite stage, except locally where volcanic
rocks have hastened the passage into low grade
bituminous varieties. Of the 44 coal areas described in
this report, a very considerable number do not promise
to be of any economic importance whatever. But it is
quite right that they should be included in any compre-
hensive report, if only as a guide to prospectors and
others who might be Jed to form wrong conclusions
from outcrop appearances. The report contains a
clearly-printed map of every coal area, and a large map in
the pocket shows the location of the separate coal fields.
Many analyses of the coals are given, and details of the
workings appear in cases where developments have
taken place.

Reduction of the Temperature in Mine Workings.

In the report of the Royal Commission on Mining
Industry at Broken Hill (Sydney, W. A. Gullick), just
published, a section is devoted to the question of the
possibility of the reduction of temperature to 75 degs.
Fahr., or if this should prove impracticable a reduction in
the hours of work in proportion to the temperature of the
mine. The Commission considered the question of what
constitutes a high temperature. The standard of
normality varies in Australia. 'In Queensland, a
Royal Commission had previously recommended a
degree of humidity represented by a dry bull? temperature
of 85 degs. Fahr, and 80 degs. Fahr, wet bulb. If the
dry bulb temperature exceeds 85 degs. Fahr., the wet
bulb must be at least 7 degs. Fahr. less. In Western
Australia the standard is 87 degs. Fahr, dry and 80 degs.
Fahr. wet. In Victoria 83 degs. Fahr, wet bulb, and in
New Zealand 80 degs. Fahr, wet bulb. It will be
recalled that in Great Britain the Royal Commission on
Mines, 1909, refused to fix a standard, but Dr. Haldane
has stated that for the economical working of a mine
the wet-bulb temperature should not be allowed to rise
above 81 degs. Fahr., unless perhaps where there is a
good ventilation current. The present report discusses
the various causes of high temperature in mines, which
are due to:—(1) The progressive increase of temperature
with depth; (2) the oxidation of minerals; (3) the
warming influence of men, animals and lights; (4)
explosives; (5) the incoming air during the summer
months; (6) rise of temperature due to increased
barometric pressure, amounting to 1 deg. Fahr, in 180 ft.
It appears that in New South. Wales there is a seasonal
variation of underground temperature amounting to
3 degs. Fahr., but this would probably be overcome by
improved ventilation. The hot places in a mine are
always the dead ends, and it generally happens that the

hottest places are those in which it is necessary to use
water to keep down the dust, which keeps the air moist
and raises the wet bulb temperature. The Commission
has come to the conclusion that a standard should be
fixed of 82 degs. Fahr., wet bulb, but a minority report
recommends 78 degs. Fahr, wet bulb. In making this
recommendation the Commission do not question the
high authority of the British Royal Commission, but
they maintain that it is a question of practical mining
conditions in Australia rather than of pure physiology.
The English Commission, they say, was considering
rather the scientific limit to human exertion in high
temperatures than the question of fixing a standard of
comfort for underground workers.

THE GERMAN AND AUSTRIAN COAL
AND IRON TRADES.

Wc give below further extracts from German
periodicals that have reached us, showing the course of
the coal and iron trades in Germany and Austria :—

Mining Properties.

The Phonix A. G. fur Bergbau and Huttcnbetrieb,
Horde, has acquired two mining areas (109,999 and
109,260 sq.m.) at Peterslahr and Roth (Altenkirchen),
for the purpose of mining iron ore, and another area of
107,590 sq. m., for iron ore and pyrites, at Burglahr,
Oberlahr and Roth.

German Pig Iron Output in June.

The total production amounted to 993,968 tons
(985,968 tons in May). Of this total, 203,849 tons
(219,040 tons) were foundry pig; 18,887 tons (16,965
tons) Bessemer pig; 612,659 tons (600,752 tons) basic
pig; 136,611 tons (121,959 tons) steel-iron and spiegel-
eisen; and 21,490 tons (27,252 tons) puddle iron.
Rhenish Westphalia produced 423,908 tons (426,268
tons); Siegerland, Wetzlar, and Hesse-Nassau, 67,202
tons (63,437 tons); Silesia, 63,291 tons (68,457 tons);
North Germany, 18,504 tons (18,867 tons); Mid-Gcr-
many, 33,082 tons (33,156 tons); South Germany and
Thuringia, 20,082 tons (20,669 tons); the Saar district,
68,374 tons (66,777 tons); Lothringen, 158,604 tons
(147,371 tons); and Luxemburg, 140,089 tons (140,606
tons).

German Output of Medium Steel in June.

The official figures for medium steel give the total pro-
duction in June as 1,080,786 tons, as compared with
1,044,107 tons in May. Of this total, 542,967 tons
(528,587 tons) were basic Bessemer; 13,635 tons (12,701
tons) acid Bessemer; 428,170 tons (419,410 tons) basic
open hearth; 22,819 tons (18,279 tons) acid open hearth,
basic cast, 39,294 tons (36,578 tons); acid cast, 15,563
tons (12,757 tons); crucible steel, 8,366 tons (8,329
tons); and electro-steel, 9,972 tons (7,448 tons). The
production in the different districts was : Rhenish West-
phalia, 631,576 tons (598,948 tons); Silesia, 88,045 tons
tons (95,459 tons); Siegerland and Hesse-Nassau,
23,877 tons (24,521 tons); North, East, and Mid-Ger-
many, 47,094 tons (45,504 tons); Saxony, 19,870 tons
(20,823 tons); South Germany, 10,942 tons (10,199
tons); Saar district and Bavarian Rhinepfalz, 81,988
tons (77,880 tons); Elsass-Lothringen, 96,838 tons
(91,230 tons); and Luxemburg, 8 0,376 tons (79,543
tons).

Export and Transit Regulations for Bar Iron and Steel
in Germany.

It is announced that the prohibition on the export and
transit of iron bars of square section has been removed.
On the other hand the export and transit of square and
round steel bars exceeding 60 mm. in diameter, square
iron (steel) bars, between 12 and 20 mm., for making
horseshoes; horseshoe steel bars of double tee section;
crucible steel castings (crude and worked) of any weight,
other steel castings weighing above 100 kilogs. each
(crude or finished); hammers, chisels, saws, beet knives
and files, are forbidden.

Ruhr Coal Market.

During July the demand for fuel was quite as pressing
as in pre-war times, and although the supply was fairly
good, coal owners are hoping that the rise in prices next
month will give them a little breathing time, and enable
deliveries in arrear to be made good. Whilst all kinds
are almost equally scarce, this is more particularly the
case with anthracite, which is in special demand for
winter stocks. It is, however, expected that there will
be sufficient for all requirements, the war having taught
all classes to be moderate in their demands. Neither is
there any prospect of prices rising to anything like the
same extent as in England, the increases prescribed by
the Coal Syndicate at the end of Jidy being very
moderate, and not to be compared with those experi-
enced by many other raw materials. The same applies
to the price of coke, deliveries of which arc consider-
ably in arrear. On the one hand, consumers who pre-
viously used only coal are extensively going in for coke,
and, on the other, the demands of the iron industry
have been growing steadily during the last few months.
The coal output is limited, and therefore the pits are not
able to keep all their coke ovens going, whilst the possi-
bility of making up the deficiency from stock coke is
hampered by the scarcity of labour accustomed to the
work. The past month was one of the most important
and eventful in the history of the Coal Syndicate, owing
to the unexpected issue of the Decree relating to the
formation of compulsory syndicates. The desirability
of a syndicate for the Ruhr district had become gener-
ally recognised, even by former opponents, and the coal
owners had been repeatedly warned that delay in coming
to an understanding would lead to the intervention of
the State. Now that this intervention has actually
come to pass, it is, however, somewhat surprising to
find that Herr Kirdorf, who has been at the head of the
syndicate for 22 years, and who, from his ability to