An Improved Method of Preventing Spontaneous Ignition and Explosion of Coal.
Year: 1894

page_text: Date of Application, 5th Mar.. 1894
Complete Specification Left, 5th Dec., 1894-Accepted, 2nd Mar., 1895
PROVISIONAL SPECIFICATION.
[Communicated from abroad by JOHANN HEINRICH CARL BEHNKE and THE
CHEMISCHE FABRIK IN BILLWÄRDER, vorm. HELL & STHAMER, A. G., of
Billwärder, ald. Bille, in the Empire of Germany.]
An Improved Method of Preventing Spontaneous Ignition and
Explosion of Coal.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby declare
the nature of this invention to be as follows:-
This invention relates to an improved method of preventing the spontaneous
ignition and explosion of coal.
It is a well-known fact that large quantities of pit-coal heaped up, particularly
cargoes of coal, if exposed for some time to moist heat, are liable to ignite
spontaneously and to give rise to explosions of gas, thus placing the ships and crew
in the greatest danger. For obviating this danger various means have already
been proposed, these however either do not fulfil their object or are a great deal
too expensive for general use. The most natural mode of preventing the said
dangerous occurrences is to withdraw the atmospheric air from the ignitible and
explosive substances of the coal, but it has not been possible up to the present time
to effect this in a very inexpensive yet sufficient manner.
One proposal to expel the air and the gases formed in the coal from the
intermediate spaces in the heap of coal consists in taking a number of bottles of
liquid carbonic acid on board and, when certain signs may render this desirable,
causing the acid to pass into the cargo of coal. Accordingly the atmospheric air is
to be replaced by an atmosphere of carbonic acid which does not permit of
spontaneous ignition and explosion.
The idea of replacing the atmospheric air by another kind of air or gas within
and around the cargo of coal is acceptable, but there are serious doubts as regards,
the proposed mode of carrying it into practice.
In the first place the question of cost has to be considered, and it can be easily
shown by calculation that the employment of liquid carbonic acid in bottles
carried on board ship for the said purpose increases the cost of transporting coal
by ships to such an extent that the employment of this means does not find
favour.
Taking into account, in addition to this impediment to the employment of liquid
carbonic acid, that in the rapid passage of carbonic acid from the bottles more than
half the acid congeals or becomes a solid snowy material which without the use of
beat volatilizes very slowly it will be evident that the use of carbonic acid in the
before-mentioned form presents difficulties not only by reason of the high cost but
also because of imperfect results.
By the improved method constituting the subject of the said invention the object
in question is attained with means which may be procured at a comparatively small
cost and are perfectly efficient.
For expelling the atmospheric air and the methane gases from the coal use is
made of smoke preferably derived from coke burned in steam boilers or coke
furnaces with or without the use of limestone. Before such smoke, which contains

page_text: on the average from 15 to 20 per cent. of carbonic acid and not more than 4 per cent_
of oxygen, is conducted into and round the coal, it is expedient to first cool it, wash.
it in water and cause it to pass through a solution of sodium carbonate in order to
free it from the sulphurous acid which attacks wood and metal and is injurious to
the health. The smoke is then conducted at a certain pressure into the hold of the
ship. The atmospheric air and the hydro-carbon gases between the coal are
dispelled upwards and thence conducted away by ventilation, so that finally the
whole hold of the ship is substantially filled only with carbonic acid and nitrogen
gases.
It is evident that the mechanical arrangement for realising the improved method
may be carried out in various ways. In cases where the cargoes of coal of steamers
are to be treated according to this method the steam boiler may be employed for the
production of the necessary smoke. As the danger of spontaneous ingnition and
explosion of the cargoes of coal on steamers is smaller than on sailing ships, because
the voyages of steamers are in most cases only of short duration, the arrange-
ments necessary for the improved method must in the first place be adapted for the
conditions prevailing on sailing ships.
Accordingly a special source for producing smoke has to be provided, which may
consist of a coke furnace put up on land or on a small steamer. From this source the
smoke is introduced into the hold of the ship through a pipe. But before this the
smoke is conducted through a scrubber or washer supplied with a continuous water
jet, then by a blower to a cooler, and is next introduced into the tubular system in
the hold. The smoke may pass from the deck first into a tube which is arranged
at a suitable height below the deck on the sides of the ship. Branch tubes extend
from this main tube along the side of the ship down to the bottom and then across
the latter. The tubes on the bottom of the ship possess numerous holes, in a
horizontal direction so that the smoke coming from these holes will first pass
horizontally through the coal piled up. It should be observed that such holes
exist in very great number below the port through which the coal is shot into the
hold, because at these points the spontaneous ignition or explosion is to be feared
most. As a natural consequence of the shooting most of the coal dust accumulates
below the said port where the coal, owing to the continual shooting, is deposited
most closely together.
As the smoke is conducted into the coal space under pressure and is moreover
considerably heavier than, the atmospheric air and the methane gases the latter
kinds of gases are expelled with certainty, and the coal is then surrounded by an
atmosphere consisting substantially of carbonic acid gas and nitrogen gas.
Although the before-described method offers in most cases a sufficient guarantee
against self-ignition and explosion, this guarantee may be further increased by
introducing at the end of introduction of gas, the contents of some bottles of fully
compressed liquid ammonia. The latter unites with the carbonic acid or the smoke
to form ammonia carbamine and deposits like a breath upon the several pieces of
coal, thereby cooling the latter a little in a favourable manner. Moreover, the
deleterious moisture which will still be present in the coal, although the greatest care
may have been taken to load the same in a dry condition, is absorbed by the ammonia
carbamine which is thus transformed into the so-called salvolatiles (ammonia
carbonate). This will also take up more of the carbonic acid present, and will be
formed into ammonia bicarbonate. The employment of compounds of ammonium
carbonate for the said purpose is particularly advantageous, because these
compounds become volatile even at from 60 to 70 degrees Centigrade.
The use of ammonia and its compounds has the following advantages. The
diffusion of the gases contained in the hold of the ship with the atmospheric air is
rendered difficult, because the gases have a greater specific gravity than without
the use of ammonia. In a sanitary respect the ammonia helps to reduce the degree
of poisonousness of the carbonic acid gas. The ammonia acts powerfully in
opposition to the oxidation, also to that of iron pyrites.
In order that these advantageous properties of ammonia may come into play

page_text: where the danger from the ignition of coal is greatest, that is to say under the
aforesaid ports it is expedient during the loading of coal to strew at these points
between the coal some handfuls of coarsely pulverized salvolatiles or ammonia
bicarbonate, so that the conical heap of coal which is formed below the said ports
will at all events be provided with this protecting agent.
As the gases introduced into the coal space completely prevent the oxidation, a
spontaneous ignition becomes impossible. As moreover the beings present in the
smoke are suffocated all the vermin in the coal space will be destroyed. On the
other hand provision is of course made for preventing the poisonous action of
the gases affecting the persons on the ship. The hold for the coal must therefore
be tightly closed, and special precautions must be taken when entering the same.
If this be necessary the gases should first be removed by surface ventilation; or if
the gases must not be removed from the coal space during the voyage the person
entering the space provides himself with a simple inhaling apparatus consisting of a
nose clamp which prevents the inhaling of the deleterious gases through the nose,
and an air pipe provided with a mouth piece through which the person inhales
fresh atmospheric air. The unloading of the coal must take place only after a
powerful surface ventilation has taken place for a few days to lead away the gases.
This ventilation has also to be continued during the unloading.
It may be desirable to give an example showing by calculation that the cost of
the described method is but slight and inay be incurred, having regard to the great
gain achieved.
Suppose a ship of 2400 cubic metres with 1440 tons of coal. There will be
about 700 cubic metres of intermediate space between the coal, and 600 cubic
metres of other free spaces which would have to be filled with smoke. Now if
smoke of 15% carbonic acid and 1% of carbonic oxide is at disposal, then
= 208 cubic metres of
1300 (700+ 600) cubic metres of smoke contain
16.1300
100
=
carbonic acid and carbonic oxide. Suppose the specific gravity of these gases to
be 0.0019, one cubic metre weighs 19 kilogrammes, that is to say, 208 cubic
metres weigh 395 kilogrammes. By deducting the weight of 1 cubic metre of
oxygen from the weight of 1 cubic metre of carbonic acid, and proceeding according
to the chemical formulæ (CO, and carbonic oxide CO) with a carbonic oxide in the
same manner, the remainder obtained for both gases will be 0.54 kilogrammes of
pure carbon which is contained in 1 cubic metre of carbonic acid or carbonic oxide. In
this calculation 1 cubic metre of carbonic acid is assumed to weigh 19 kilogrammes.
1 cubic metre of carbonic oxide 1.25 kilogrammes and 1 cubic metre of oxygen
1.43 kilogrammes. In order to produce the aforesaid 208 cubic metres of carbonic
112 kilogrammes
acid and carbonic oxide it would be necessary to burn 0.54 208
of pure carbon. As however coke is not pure carbon and loss of material has also
to be taken into consideration it will be necessary to use about 150 kilogrammes of
coke for producing the computed amount of smoke. This quantity of coke would
cost about 4/- assuming the attendance on the furnace and the introduction of
smoke while working for one hour to cost 3/-, and the sinking fund and the interest
on the capital which has to be expended for a special furnace and for the feed
apparatus in the ship for each introduction of smoke to amount each time to about
10 to 13 shillings, the total cost of carrying the improved method into practice
once for a ship having a hold of 2400 cubic metres would only be from 17 to
20 shillings.

page_text: An Improved Method of Preventing Spontaneous Ignition and
Explosion of Coal.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention, and in what manner the same is to be
performed, to be particularly described and ascertained, in and by the following
statement :-
This invention relates to an improved method of preventing the spontaneous
ignition and explosion of coal.
It is a well known fact that large quantities of pit-coal heaped up, particularly
cargoes of coal, if exposed for some time to moist heat, are liable to ignite spon-
taneously and to give rise to explosions of gas, thus placing the ships and crew in
the greatest danger..
For obviating this danger various means have already been proposed, these
however either do not fulfil their object or are a great deal too expensive for general
aise. The most natural mode of preventing the said dangerous occurrences is to
withdraw the atmospheric air from the ignitible and explosive substances of the
coal, but it has not been possible up to the present time to effect this in a very
inexpensive yet sufficient manner.
One proposal to expel the air and the gases formed in the coal from the inter-
mediate spaces in the heap of coal consists in taking a number of bottles of liquid
carbonic acid on board and, when certain signs may render this desirable, causing
the acid to pass into the cargo of coal. Accordingly the atmospheric air is to be
replaced by an atmosphere of carbonic acid which does not permit of spontaneous
ignition and explosion.
The idea of replacing the atmospheric air by another kind of air or gas within
and around the cargo of coal is acceptable, but there are serious doubts as regards
proposed mode of carrying it into practice.
In the first place the question of cost has to be considered, and it can be easily
shown by calculation that the employment of liquid carbonic acid in bottles carried
on board ship for the said purpose increases the cost of transporting coal by ships
to such an extent that the employment of this means does not find favour.
Taking into account, in addition to this impediment to the employment of liquid
carbonic acid, that in the rapid passage of carbonic acid from the bottles more than
half the acid congeals or becomes a solid snowy material which without the use of
heat volatilizes very slowly, it will be evident that the use of carbonic acid in the
beforementioned form presents difficulties not only by reason of the high cost but
also because of imperfect results.
By the improved method constituting the subject of the said invention the object
in question is attained with means which may be procured at a comparatively small
cost and are perfectly efficient.
For expelling the atmospheric air and the methane gases from the coal use is
made of smoke preferably derived from coke burned in steam boilers or coke
furnaces with or without the use of limestone. Before such smoke, which contains
on the average from 15 to 20 per cent. of carbonic acid and not more than 4 per cent.
of oxygen, is conducted into and round the coal, it is expedient to first cool it, wash
it in water and cause it to pass through a solution of sodium carbonate in order to
free it from the sulphurous acid which attacks wood and metal and is injurious to
the health. The smoke is then conducted at a certain pressure into the hold of
the ship.
The atmospheric air and the hydro-carbon gases between the coal are dispelled

page_text: upwards and thence conducted away by ventilation, so that finally the whole hold
of the ship is substantially filled only with carbonic acid and nitrogen gases.
It is evident that the mechanical arrangement for realising the improved methot
may be carried out in various ways. In cases where the cargoes of coal of steamers.
are to be treated according to this method the steam boiler inay be employed for
the production of the necessary smoke. As the danger of spontaneous ignition an
explosion of the eargoes of coal on steamers is smaller than on sailing ships, because
the voyages of steamers are in most cases only of short duration, the arrangements.
Decessary for the improved method must in the first place be adapted for the
conditions prevailing on sailing ships.
Accordingly a special source of producing smoke has to be provided, which may-
consist of a coke furnace put up on land or on a small steamer.
From this source
the smoke is introduced into the hold of the ship through a pipe. But before this
the smoke is conducted through a scrubber or washer supplied-with a continuous
water jet, then by a blower to a cooler, and is next introduced into the tubular
system in the hold. The smoke may pass from the deck first into a tube which is
arranged at a suitable height below the deck on the sides of the ship. Branch
tubes extend from this main tube along the side of the ship down to the bottom
and then across the latter. The tubes on the bottom of the ship possess numerous
holes, in a horizontal direction so that the smoke coming from these holes will first.
pass horizontally through the coal piled up. It should be observed that such holes
exist in very great number below the port through, which the coal is shot into the.
hold, because at these points the spontaneous ignition or explosion is to be feared
most. As a natural consequence of the shooting most of the coal dust accumulates.
below the said port where the coal, owing to the continued shooting, is deposited
most closely together.
As the smoke is conducted into the coal space under pressure and is moreover
considerably heavier than the atmospheric air and the methane gases the latter
kinds of gases are expelled with certainty, and the coal is then surrounded by an
atmosphere consisting substantially of carbonic acid gas and nitrogen gas.
Although the before-described method offers in most cases a sufficient guarantee
against self-ignition and explosion, this guarantee may be further increased by
introducing at the end of the introduction of gas, the contents of some bottles of
compressed liquid ammonia. The latter unites with the carbonic acid or the smoke
to form ammonia carbamine and deposits like a breath upon the several pieces of
coal, thereby cooling the latter a little in a favourable manner. Moreover, the
deleterious moisture which will still be present in the coal, although the greatest
care may have been taken to load the same in a dry condition, is absorbed by the
ammonia carbamine which is thus transformed into the so-called salvolatiles
(ammonia carbonate). This will also take up more of the carbonic acid present,.
and will be formed with ammonia bicarbonate. The employment of compounds of
ammonium carbonate for the said purpose is particularly advantageous, because
these compounds become volatile even at from 60 to 70 degrees Centigrade.
The use of ammonia and its compounds has the following advantages. The
diffusion of the gases contained in the hold of the ship with the atmospheric air is
rendered difficult, because the gases have a greater specific gravity than without
the use of ammonia. In a sanitary respect the ammonia helps to reduce the degree
of poisonousness of the carbonic acid gas. The ammonia acts powerfully in
opposition to the oxidation, also to that of iron pyrites.
In order that these advantageous properties of ammonia may come into play
where the danger from the ignition of coal is greatest, that is to say, under the
aforesaid ports it is expedient during the loading of coal to strew at these points.
between the coal some handfuls of coarsely pulverized salvolatiles or ammonia
bicarbonate, so that the conical heap of coal which is formed below the said ports
will at all events be provided with this protecting agent.
As the gases introduced into the coal space completely prevent the oxidation, a
spontaneous ignition becomes impossible. As moreover the beings present in the

page_text: smoke are suffocated all the vermin in the coal space will be destroyed. On the
other hand provision is of course made for preventing the poisonous action of
the gases affecting the persons on the ship. The hold for the coal must therefore
be tightly closed, and special precautions must be taken when entering the same.
If this be necessary the gases should first be removed by surface ventilation, or if
the gases must not be removed from the coal space during the voyage the person
entering the space provides himself with a simple inhaling apparatus consisting of
a nose clamp which prevents the inhaling of the deleterious gases through the nose,
and an air pipe provided with a mouth piece through which the person inhales
fresh atmospheric air. The unloading of the coal must take place only after a
powerful surface ventilation has taken place for a few days to lead away the gases.
This ventilation has also to be continued during the unloading.
It may be desirable to give an example showing by calculation that the cost of
the described method is but slight and may be incurred, having regard to the great
gain achieved.
16.1300
100
Suppose a ship of 2400 cubic metres with 1440 tons of coal. There will be
about 700 cubic metres of intermediate space between the coal, and 600 cubic metres
of other free spaces which would have to be filled with smoke. Now if smoke
of 15% carbonic acid and 1% of carbonic oxide is at disposal, then 1300
(700600) cubic metres of smoke contain
=208 cubic metres of carbonic
acid and carbonic oxide. Suppose the specific gravity of these gases to be 0.0019,
one cubic metre weighs 1-9 kilogrammes, that is to say, 208 cubic metres weigh
395 kilogramines. By deducting the weight of 1 cubic metre of oxygen from the
weight of 1 cubic metre of carbonic acid, and proceeding according to the chemical
formulæ (CO, and carbonic oxide CO) with a carbonic oxide in the same manner,
the remainder obtained for both gases will be 0.54 kilogrammes of pure carbon which
is contained in 1 cubic metre of carbonic acid or carbonic oxide. In this calculation
1 cubic metre of carbonic acid is assumed to weigh 1.9 kilogrammes. 1 cubic metre
of carbonic oxide 1.25 kilogrammes, and 1 cubic metre of oxygen 1.43 kilogrammes.
In order to produce the aforesaid 208 cubic metres of carbonic acid and carbonic
oxide it would be necessary to burn 0.54-208 = 112 kilogrammes of pure carbon.
As however coke is not pure carbon and loss of material has also to be taken into
consideration it will be necessary to use about 150 kilogrammes of coke for
producing the computed amount of smoke. This quantity of coke would cost
about 4-; assuming the attendance on the furnace and the introduction of smoke
while working for one hour to cost 3/-, and the sinking fund and the interest on the
capital which has to be expended for a special furnace and for the feed apparatus
in the ship for each introduction of smoke to amount each time to about 10
to 13 shillings, the total cost of carrying the improved method into practice once
for a ship having hold of 2400 cubic metres would only be from 17 to 20 shillings.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
The herein-described method of preventing spontaneous ignition and explosion
of coal, which consists in introducing into the coals stored up carbonic acid gas
directly produced by combustion, either alone or together with ammonia or its
carbonates, substantially as and for the purpose set forth.
Dated this 5th day of December 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.