Improvements in the Production of Water Gas and in Apparatus.
Year: 1896

page_text: Date of Application, 28th Dec.,. 1896-Acospted, 20th Mar., 1897
., COMPLETE SPECIFICATION (AMENDED).
Improvements in the Production of Water Gas and in Apparatus
.: therefor..
I, CARL' DELLWIK, Engineer, of 6 Grefgatan. Stockholm in the Kingdom of Sweden,
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 state-
ment:
The present invention relates to a new process for manufacturing water-gas and to
suitable apparatus for the practical application of this process. By "water-gas" is
generally understood the gases produced by the decomposition of steam by coals coke
or other suitable fuel at a white heat, and which may be considered as consisting
mainly of a mixture of hydrogen and oxide of carbon. In this decomposition a large
amount of heat taken from the coal is absorbed. If therefore the coals are heated,
as is generally the case, by blowing air into furnaces or so-called generators and not
into specially heated retorts, then in order to again raise the temperature of the com-
.bustible material (coke coals or the other fuel) which has fallen in consequence of the
decomposition, of the steam, that is to say during the period of the production of gas,
it becomes necessary to shut off the admission of steam and to introduce air instead,
in order to revive the fire., In this manner in the production of water gas by generators,
the periods of production of gas (by the introduction of steam) and of the introduction
of air to revive the fire, constantly alternate.
.. In the hitherto known processes for manufacturing watergas the object in view has
been to supply to the coals arranged in layers of great height, during the air supply
period such a quantity of air as to cause the coals to born incompletely and produce
oxide of carbon, but not to effect a complete combustion, resulting in the production
of carbonic acid; the effect aimed at being to produce during the air supply period
a combustion product containing (together with free nitrogen) as much carbonic oxide
as possible,combustible and suitable for heating purposes,or in other words,to produco
so-called, producer-gas. The hitherto employed processes for the manufacture of
water-gas, have therefore been characterised by the combustion products obtained
during the air supply period (the so-called producer-gas) containing more carbonic
oxide than carbonio acid. "This fact constitutes a distinct demarcation line separating
the processes hitherto used from the new method which forms the subject of the
presont application and the aim of which on the contrary, is to obtain during the air
supply, period combustion products containing a larger quantity of carbonic acid than
of carbonic oxide. The new method does not therefore aim, at the production, during
the air supply period, of a combustible producer-gas that is to say a gas containing

page_text: chiefly carbonio oxide; its aim on the contrary is to considerably increase the production
of water-gas, the heating value of which is four times greater than that of the best
producer-gas.
The practical advantages of this new process are very great. While hitherto in
order to produce water-gas during a period of 4 or at the utmost 6 minutes, an air
supply period of 15 to 20 minutes was required, to raise the temperature of the fuel
to the extent necessary for the decomposition of steam; experiments with the new
process have shown an air supply period of 3 to 4 minutes to be sufficient to render
possible a gas production period of 12 to 17 minutes, before a fresh introduction of
air becomes necessary. It is well known that carbon, when burning so as, to form
oxide of carbon develops, scarcely one third of the heat capable of being developed if
the same quantity of carbon is burned so as to produce carbonio acid. The object of
the present invention is to conduct the process, so as to produce during the air supply
period a gas containing as much carbonio acid as possible and as little oxide of
carbon as possible an aim directly opposite to the object of all the various processes
hitherto employed. By the new method, therefore, a mach greater amount of heat is
generated and an adequate saving of fuel effected, the volume of water-gas produced
with the same amount of fuel being doubled in consequence while the time of the air
supply period is correspondingly reduced and that of the gas production considerably
increased.
The purpose of the present invention is attained by regulating the proportion
between the height, volume and size of coal, coke or other suitable fuel employed and
the amount of air admitted in such a manner as to cause a complete combustion of
carbon to carbonic acid. By properly proportioning the air supply to the height of
combustible fuel combustion products are with certainty obtained during the air
supply period, which to the absolute or nearly absolute exclusion of carbonic:oxide,
contain only or chiefly carbonic acid, besides nitrogen. The exact proportion varies
of course in accordance with the nature of the combustible material employed and
"other circumstances and must be determined experimentally in each separate case.
For coke of average.size for instance it has been found that with an air pressure of
210 millimetres water under the grate and with 60 millimetres above the layer
of coke (that is to say with an absolute pressure of 150 millimetres in the layer of
coke), the height of the latter should be about 1200 millimetres in order to obtain
combustion gases nearly free from oxide of carbon and containing about 20% of
carbonic acid. Such a height of coke is also sufficient to completely decompose the
steam admitted during the period of the production of gas. According to whether
it is desired to use the fuel in layere of greater or less height, the air supply is
increased (by means of an increase of pressure) or else diminished so as to produce
in each instance during the air supply period a complete combustion of the fuel to
carbonic acid. For this end it is equally practicable to regulate the height of coke
or other fuel in accordance with a given pressure of the air supplied, as to make the
reverse adjustment, i.e., to proportion the pressure of air in accordance with a given
height of coke or other fuel; but in all cases experiments will indicate a certain
definite proportion according to which for a certain pressure of air supplied a certain
definite height of coke or other fuel must be maintained.
For the application of the process according to the present invention any water gas
apparatus may be used, if only the height of coke is regulated by frequent and regular
charging in of fresh.fuel so as to keep it at a certain and approximately constant height
which shall ensure complete combustion to carbonic acid according to the pressure
of the air supplied. It is however preferable to use an apparatus in which the height
of coke is maintained constant in an automatic manner. For the determination
of the most suitable height corresponding to a given pressure of the air supply, it is
advisable to use a device having an adjustable coal receptacle.
Such apparatus is represented in Figure 1 of the accompanying drawing. A is the
generator provided with a coal receptacle B say of cast iron, this coal receptacle passes
through a stufflug box D placed on the cover or top of the generator. Under the

page_text: grating is arranged the main air inlet Land the gas outlet I and steam inlet S'. The
generator is also provided with oleaning doors Hand H. In the upper part there is
an outlet pipe E for the combustion products, which pipe is closed during the period
of the production of water gas by the valve or cover F. It is an outlet for water gas
and S is a second steam inlet. The coal receptacle B is charged with coal, coke or
othor suitable fuel and then closed by the door or cover C. The air inlet is arranged
under the grate and preferably continued into the layers of fuel by an appropriate
pipe G provided with numerous air nozzles or apertures, so that a thorough contact
of the air with the whole mass of fuel is obtained. When the proper height of a given
description of fuel for a given amount of air pressure has been determined by
testing by means of the adjustable receptacle B shown in Figure 1, the cast iron
receptacle is advantageously replaced by one made of fire bricks, as illustrated in
Figure 2.
A still simpler method of working according to the present process consists in
regulating the pressure of the air supply in accordance with a given height of fuel
maintained at a constant height. In order to keep the fuel constantly at the same
level, the apparatus shown in Figure 8 may be employed wherein it will be seen that
the inclined supply reservoir B can only supply its contents to the generator as the
combustion proceeds.
Figure 4 shows a construction of a horizontal grating, (similar to Figure 1) to which
there are provided two supply reservoirs for fuel; they are shown in the drawing
arranged at the sides of the gonerator, but may equally well be arranged in the
generator as in Figure 2.
It may also be remarked that it is advisable during the period of the production
of gas to admit steam alternately first from the top through the pipe S (Figures 1 and 2)
and then from below through the pipe S' and accordingly to discharge or lead off the
water gas first through the pipe land then through the pipe I'. The result of this
will be to keep the temperature as uniform as possible throughout the mass of fuel,
and the removal of the slag will be easily effected.
Of course, the waste heat during the air supply period may be also utilized in this
process for superheating steam or air etc, as has been done in the processes hitherto
used. But this expedient affords only a partial compensation for the heat commonly
expended during the air supply period; the result of it all being that the heat
absorbed by the fuel (i.e., the only heat utilized in the decomposition of steam)
during the air supply period is in the new process four times as great, or if the air
is not previously heated in applying the old processes, six times as great from each
kilogram of coke as in the old processes, which latter during the air supply period
produce chiefly carbonic oxide instead of chiefly carbonic acid. The great superiority
of the present process for the production of water gas over those hitherto in use is
thus clearly demonstrated.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
5
1. In the production of water gas the admission during the air supply period of
such quantity of air, or the use of such air pressure as to obtain during said air
supply period the most porfect conversion possible of the fuel to carbonic acid, so
that the combustion gases of the air supply period always contain more carbonic
acid, than carbonic oxide, substantially as described.
2.
An-apparatus-for-the-process-described-in Claim 1-in which the height-of--fuel
is-automatically-maintained constant-at-a-certain--level-previously-determined--in
accordance-with-a-given-supply-of-air-pressure.
3-The-construction of apparatus-for-the-purpose-described; consisting-of-a--coal,
eoke or fuel-reservoir B, the lower-part-of-which-is-capable-of-vertical-adjustment
relatively to the bottom of the-generator, so that it is possible-to-determine-or

page_text: regalate-the-height-of-the-fuel-according to the-given air-supply-or-pressure-sub-
stantially-as-described.
تيمم
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