A New or Improved Process for the Manufacture of Carbonic Acid Gas and Hydrogen Gas and for the Separation of the two Gases, and Apparatus therefor.
Year: 1891

page_text: Date of Application, 21st Dec., 1891
Complete Specification Left, 21st Sept., 1892-Accepted, 22nd Oct., 1892
PROVISIONAL SPECIFICATION.
A New or Improved Process for the Manufacture of Carbonic Acid
Gas and Hydrogen Gas and for the Separation of the two Gases,
and Apparatus therefor.
We, JOHN PULLMAN, of 17, Greek Street, Soho Square, in the County of
Middlesex, Manufacturer, and HERBERT SAMUEL ELWORTHY, of 31, Gurney
Road, Stratford, in the County of Essex, Analytical Chemist, do hereby declare
the nature of this invention to be as follows:-
-
This process is based upon the physical properties of the two gases hydrogen and
carbonic acid gas, chemically known as carbon di-oxide, that is to say :-
1st. On the difference in their rates of diffusion through porous media.
2nd. On the difference in their solubility in water.
The difference in the rate of diffusion of gases through porous media, is nearly in
an inverse ratio to the square roots of their respective densities.
Carbonic acid gas being nearly 22 times as heavy as hydrogen, the hydrogen will
pass through a given medium nearly 4 times as rapidly.
Again carbonic acid gas being very soluble in water and hydrogen gas being
only very slightly soluble in that liquid, a very considerable separation of the two
gases may be effected, by either compressing a mixture of the two gases into a
strong vessel partially filled with water or by passing the mixture through an
ordinary gas scrubber over which water is flowing.
We carry out the improved process as follows:-
Steam is generated in an ordinary boiler, and superheated in pipes passing
through a furnace, it is then passed over red hot coke or charcoal contained in a
cast iron retort as in the manufacture of what is well known as water gas. The
steam is thereby decomposed principally into hydrogen and carbonic acid gas, and
carbonic oxide gas. By taking care to keep the steam in excess the production of
the carbonic oxide gas may he reduced to a minimum.
We have now a mixture of two volumes of hydrogen to one volume of carbonic
acid gas, or four parts of hydrogen by weight and twenty-two parts of carbonic acid
gas also by weight, with traces of carbonic oxide.
The hot mixture of gases is now cooled by passing them through a coiled pipe
immersed in water-preferably the feed water for the boiler-whereby economy is
effected and then into the diffuser or separator.
The diffuser may consist of two chambers an outer divided chamber and an inner
one, through the latter a series of pipes composed of plaster of Paris, baked earthen-
ware unglazed, or any other suitable sufficiently porous material, are passed, their
ends being made air-tight in the walls of the chamber. On now passing the mixed
gases into one end of the outer chamber, they will pass through the porous pipes
into the other end of the outer chamber and during their passage a large proportion
of the hydrogen will pass through the porous walls of the pipes into the inner chamber
from whence it may be drawn by a suitable air pump or other equivalent device.
The walls of the inner chamber may also be composed of porous material entirely,
or of a framework of iron or other material, preferably in the form of open network
or trellis work, the interstices being filled with the porous substance. Or the outer
chamber may be partially or entirely filled with a series of porous vessels of any
suitable shape, each of the porous vessels being connected by means of a suitable
tube or pipe to a main pipe. These vessels may be composed entirely of the porous
material, or of an open framework of metal or other suitable material, and having
the interstices filled with the porous material as already described.
The mixed gases are passed into the outer chamber either intermittently or con-
tinuously, and either at atmospheric pressure, or under any suitable pressure either

page_text: higher or lower, and a slight vacuum may also be maintained in the porous vessels,
or in the interior of the inner chamber. The process may be repeated any number
of times found necessary to effect as complete a separation as possible.
may
bc
The nearly pure hydrogen may be now compressed into suitable vessels partially
filled with water whereby most of the remaining carbonic acid gas is absorbed.
On now opening the valve of the vessel the hydrogen rapidly escapes and
caught and retained in a suitable vessel, and, thence, for final purification, either
passed through a scrubber over which water is flowing whereby the remaining
traces of carbonic acid gas are washed away. Or it may be passed over damp
hydrate of lime or through milk of lime or through or over any other substance
capable of absorbing or combining with the carbonic acid gas. The
may now be collected dried if necessary, and compressed in suitable vessels for sale
pure hydrogen
or use.
The carbonic acid gas which has been nearly freed from hydrogen by passing
through the porous tubes or remaining in contact with the porous vessels, may be
completely freed from the remaining traces of hydrogen and from the carbonic
mon-oxide by passing it through a tube or series of tubes containing oxide of copper
or other easily reducible metallic oxide, heated to a red heat. The oxide of copper
may be in the form of commercial black oxide, or the tubes may be filled with
copper filings, turnings, wire, nails, or gauze, and after being made red hot a current
of air may be passed through the tubes whereby the copper is partially oxidized.
On passing the mixed gases over the red hot copper oxide, the oxide is partially
reduced converting the hydrogen into water and the carbonic mon-oxide into
carbonic acid gas. The copper may be re-oxidized as often as required by again
passing air over it at a low red heat.
The carbonic acid gas is now pure and may be collected compressed and utilized
in the manufacture of mineral waters, or for other suitable purpose.
Instead of using the porous chamber or tubes or vessels for separating the gases,
we may take the latter direct from the cooling worm and compress them into strong
metal vessels partially filled with water, as before mentioned.
The carbonic acid gas being very soluble in water especially under pressure, is
dissolved to a large extent, and on opening the valve the hydrogen rapidly escapes
and may be collected in suitable vessels. The carbonic acid gas escaping more
slowly may be caught in a separate receiving vessel. The gases may be submitted
to this process several times over, and finally purified as above described.
Glycerine or hydrocarbon oil (which absorb more gas and part with it more
slowly) may be substituted for the water in the above described vessels, and the
vessels may be fitted with an agitating device to promote the absorption of the
carbonic acid gas, or the vessels themselves may be made to revolve or turn over.
Dated this 21st day of December 1891.
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
A New or Improved Process for the Manufacture of Carbonic Acid
Gas and Hydrogen Gas and for the Separation of the two Gases,
and Apparatus therefor.
We, JOHN PULLMAN, of 17, Greek Street, Soho Square, in the County of
Middlesex, Manufacturer, and HERBERT SAMUEL ELWORTHY, of 31, Gurney
Road, Stratford, in the County of Essex, Analytical Chemist, do hereby declare
the nature of this invention and in what mauner the same is to be performed, to
be particularly described and ascertained in and by the following statement and
accompanying drawing, that is to say :-
This process is based upon the physical properties of the two gases, hydrogen,
and carbonic acid gas (chemically known as carbon di-oxide) that is to say :

page_text: Ist. On the difference in their rates of diffusion through porous media.
2nd. On the difference in their solubility in water.
The difference in the rate of diffusion of gases through porous media, is nearly in
an inverse ratio to the square roots of their respective densities.
Carbonic acid gas being nearly 22 times as heavy as hydrogen the hydrogen will
pass through a given medium nearly 4 times as rapidly."
Again carbonic acid gas being very soluble in water and hydrogen gas being
only very slightly soluble in that liquid, a very considerable separation of the two
gases may be effected, by either compressing a mixture of the two gases into a
strong vessel partially filled with water or by passing the mixture through an
ordinary gas scrubber over which water is flowing.
We carry out the improved process as follows-
Steam is generated in an ordinary boiler, and superheated in pipes passing
through a furnace, it is then passed over red hot coke or charcoal contained in
a cast iron retort as in the manufacture of what is well known as water gas,
The steam is thereby decomposed principally into hydrogen and carbonic acid
gas, and carbonic oxide gas. By taking care to keep the steam in excess, the
production of the carbonic oxide gas may be reduced to a minimum.
We have now a mixture of two volumes of hydrogen to one volume of carbonic
acid gas, or four parts of hydrogen by weight and twenty-two parts of carbonic
acid gas also by weight, with traces of carbonic oxide.
The hot mixture of gases is now cooled by passing them through a coiled
pipe immersed in water-preferably the feed water for the boiler, whereby
economy is effected and then into the diffuser or separator, which is illustrated in
the accompanying drawing, in which Figure 1 is a longitudinal and Figure 2 a
transverse vertical section
The diffuser may consist of two chambers an outer chamber a and an inner
one formed by walls b, b, which divide the outer chamber a. Through the
walls a series of pipes c composed of plaster of Paris, baked earthenware
unglazed, or any other suitable sufficiently porous material, are passed, their
ends being made air-tight in the walls of the chamber. On now passing the
mixed gases into one end of the outer chamber say at d, they will pass through
the porous pipes c into the other end of the outer chamber a and during their
passage a large proportion of the hydrogen will pass through the porous walls
of the pipes c into the inner chamber from whence it may be drawn by a suit-
able air pump or other equivalent device through a pipe at f.
•
The walls b, b, of the inner chamber may also be composed of porous material
either entirely, or of a framework of iron or other material, preferably in the
form of open network or trellis work, the interstices being filled with the porous
substance. Or, in a somewhat modified form the outer chamber a may be partially
or entirely filled with a series of closed porous vessels of any suitable shape,
the interior of each of the porous vessels being connected by means of a suitable
tube or pipe to a main pipe, through which the hydrogen passing through the
porous vessels is withdrawn.
These vessels may be composed entirely of the porous material, or of an open
framework of metal or other suitable material, having the interstices filled with the
porous material as already described.
The mixed gases are passed into the outer chamber a either intermittently or
continuously, and either at atmospheric pressure, or under any suitable pressure
either higher or lower, and a slight vacuum may also be maintained in the porous
vessels last described, or in the interior of the inner chamber formed by the
walls b, b. The process may be repeated any number of times found necessary to
effect as complete a separation as possible.
The nearly pure hydrogen may be now compressed into suitable vessels partially
filled with water whereby most of the remaining carbonic acid gas is absorbed.
On now opening the valve of the vessel the hydrogen rapidly escapes and

page_text: may be caught and retained in a suitable vessel, and, thence, for final purifi-
cation, either passed through a scrubber over which water is flowing whereby
the remaining traces of carbonic acid gas are washed away. Or it may be passed
over damp hydrate of lime or through milk of lime or through or over any other
substance capable of absorbing or combining with the carbonic acid gas. The pure
hydrogen may now be collected, dried if necessary, and compressed in suitable
vessels for sale or use.
The carbonic acid gas which has been nearly freed from hydrogen by passing
through tubes or remaining in contact with the porous vessels is withdrawn at e and
may be completely freed from the remaining traces of hydrogen and from the
carbonic mon-oxide by passing it through a tube or series of tubes containing
oxide of copper or other easily reducible metallic oxide, heated to a red heat.
The oxide of copper may be in the form of commercial black oxide, or the tubes
may be filled with copper filings, turnings, wire, nails, or gauze, and after being
made red hot a current of air may be passed through the tubes whereby the copper
is partially oxidized. On passing the mixed gases over the red hot copper oxide,
the oxide is partially reduced converting the hydrogen into water and the carbonic
mon-oxide into carbonic acid gas. The copper may be re-oxidized as often as
required by again passing air over it at a low red heat.
The carbonic acid gas is now pure and may be collected compressed and utilized
in the manufacture of mineral waters, or for other suitable purposes.
Instead of using the porous chamber or tubes or vessels described and illustrated
for separating the gases, we may take the latter direct from the cooling worm and
compress them into strong metal vessels partially filled with water, as before
mentioned.
The carbonic acid gas being very soluble in water especially under pressure, is
dissolved to a large extent, and on opening the valve the hydrogen rapidly escapes
and may be collected in suitable vessels. The carbonic acid gas escaping more
slowly may be caught in a separate receiving vessel. The gases may be submitted
to this process several times over, and finally purified as above described.
Glycerine or hydrocarbon oil (which absorb more gas and part with it more
slowly) may be substituted for the water in the above described vessels, and the
vessels may be fitted with an agitating device to promote the absorption of the
carbonic acid gas, or the vessels themselves may be made to revolve or turn over.
We do not confine ourselves to the precise details of the apparatus and process,
which may be varied more or less as may be found desirable, but
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. The method of manufacturing carbonic acid gas and hydrogen gas, and of
separating the two gases, consisting:-First, of decomposing superheated steam
by passing it over red hot coke or charcoal in a retort and cooling the resulting hot
mixture of gases. Second, separating the gases by means of diffusion through
porous material, substantially as described.
2. The method of separating the hydrogen gas from carbonic acid gas, by
compressing them into a vessel partially filled with water in which the carbonic
acid gas is absorbed, then opening a valve in the vessel and allowing the hydrogen
to escape and be retained in a suitable vessel, the carbonic acid gas remaining in
solution, substantially as described.
3. In combination with the methods described in Claims and 2, the method
of completely freeing the carbonic acid gas from the remaining traces of hydrogen
and from carbon mou-oxide by passing it over oxide of copper or other easily
reducible metallic oxide, at a red heat, substantially as described.
4. In the process described and claimed in Claim 2, the use instead of water
of glycerine or hydrocarbon oil, substantially as and for the purpose described.

page_text: 5. In the process for separating carbonic acid gas and hydrogen gas, described
in Claim 1, the diffusion apparatus consisting of the outer chamber a, the inner
chamber formed by the walls b, b, the porous pipes c, and the inlet and outlet
openings for the gases, substantially as described and illustrated.
6. In the processes for separating carbonic acid gas and hydrogen gas, described
in Claim 1, the diffusion apparatus consisting of an outer chamber provided with
inlet and outlet pipes and filled with closed porous vessels connected by pipes with
a main pipe, substantially as described.
Dated this 21st day of Santamhov 1802
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicants.