An Improved Method of and Apparatus for Producing Carbonic Acid Gas.
Year: 1893

page_text: Date of Application, 3rd July, 1893
Complete Specification Left, 3rd May, 1894-Accepted, 9th June, 1894
PROVISIONAL SPECIFICATION.
An Improved Method of and Apparatus for Producing Carbonic
Acid Gas.
We, HOWARD LANE, of Corporation Street, Birmingham, Engineer, and JOHN
PULLMAN, of 17, Greek Street, Soho, in the County of Middlesex, Manufacturer,
do hereby declare the nature of this invention to be as follows:-
This invention relates to a new or improved method of economically and rapidly
obtaining carbonic acid gas and to apparatus to be used in connection with such
method.
The improved process consists substantially in passing atmospheric air which
the apparatus contains at the commencement of the process through a retort or
chamber containing heated carbon, thus producing carbonic oxide gas, which is
then passed through a second heated retort or chamber containing a metallic oxide
by which the carbonic oxide is converted into carbonic acid, and is at the same
time considerably increased in volume. A part (constituting the surplus) of the
carbonic acid gas thus obtained is passed to a gas holder and washer, and can
then be utilized in any desired way, whilst the remainder (more or less equal to
the volume of the carbonic oxide) is passed back to and through the first retort
where it is again converted to carbonic oxide the latter being returned once more
to the second retort and passed through the heated metallic oxide in the latter, and
being again converted to carbonic acid gas of increased volume, a part of which is
carried off to be used, whilst the remainder again returns to the first retort, and so
on as long as may be desired.
When the metallic oxide becomes reduced by giving up its oxygen to the
carbonic oxide, a current of air (preferably heated) is passed through it until it
has become sufficiently re-oxidized, and the process is then continued as already
described.
It is evident that the details of the apparatus used in the improved process may
be varied more or less and the following description is illustrative only of the
method of construction and arrangement which we prefer to use.
The apparatus consists of a vertical retort or chamber, preferably of fireclay
and lined with a wrought iron tube. This retort is set in a brickwork chamber
and is heated by a furnace of suitable construction. The lower end of the retort
may be open and made to dip into a water pan or vessel so arranged that ashes
and refuse from the retort may be removed without stopping the work. The upper
end of the retort is provided with a cover or cap, having a door through which
the retort can be conveniently charged, an inlet pipe passing through the cover
and centrally down nearly to the bottom of the retort. An outlet pipe is also
arranged from the top of the retort.
The retort is charged, as required, with charcoal, coke, or other suitable
carbonaceous material, upon the purity of which that of the resulting gas will
depend.
In a convenient position in the neighbourhood of the retort just described is
arranged a second retort or chamber preferably horizontal, and of cast iron,
wrought iron plates, or other suitable material. This chamber is fitted with a
sufficient number of perforated fire-brick trays upon which is placed oxide of
In order to prevent or
copper or of other suitable metal in a finely divided state.
reduce the action of the oxide upon the material of which this retort is made, we
preferably interpose asbestos in suitable form between the oxide and the walls of
the retort, and the latter is provided with a suitable manhole and door by which

page_text: access can be had to its interior, and with an inlet pipe entering below the trays
The retort is set in a
carrying the oxide, and an outlet pipe above the latter.
suitable firebrick chamber and is heated by the waste heat from the retort first
described, or by other suitable means.
The outlet pipe from the second retort is connected with the inlet pipe descending
through the centre of the first retort, and the outlet pipe of the latter is connected
with the inlet pipe to the second retort, and in a suitable part of the circuit of
pipes thus formed, preferably in the outlet pipe from the second retort, is inserted
a blowing apparatus of any suitable kind (such for instance as what is well known
"Root's" blower) capable of operating upon hot gases, its object being to
cause the constant circulation of the gases produced, through the different parts of
the apparatus.
as a
An ordinary fan, or other equivalent apparatus for dealing with large quantities
of air is also arranged in connection with the inlet pipe into the lower part of the
second, or oxidizing, furnace described, or in other suitable position, so that when
required air can be driven through the metal upon the trays for the purpose of
re-oxidizing it. A pipe communicating preferably with the open air is arranged
upon the delivery pipe from the second retort.
Regulating valves are arranged upon this pipe just described, upon the delivery
pipe of the fan, upon the pipe communicating from the upper part of the first
retort to the lower part of the second retort, and upon the delivery pipe from the
upper part of the second retort to the top of the pipe descending to the lower part
of the first retort, which valves can be opened and closed according to the different
parts of the process which are being carried on.
The circulating pump and the fan described are driven by steam or any convenient
power.
The process for manufacturing carbonic acid gas by means of apparatus of the
kind described, is as follows:-
The first retort is filled with carbon, and the trays in the second retort with
The valves on the delivery
copper oxide or scale, or other suitable metallic oxide.
from the fan and upon the pipe communicating between the delivery pipe of the
second furnace and the open air, are closed and the other valves opened. The
circulating blower is then set in motion, and both retorts are heated, the first to a
bright red and the second to a low red heat.
The entire system, in this condition, contains atmospheric air, that is to say a
mixture of nitrogen and oxygen gases.
The oxygen combines with the carbon and is converted to carbonic acid gas in
the lower part of the first retort and as it rises is further converted to carbonic
oxide gas.
The resulting mixture of carbonic oxide and nitrogen gases is passed by the
action of the circulating blower from the upper part of the first retort and into
the lower part of the second (or oxidizing) retort and passing up through the
copper oxide the carbonic oxide becomes converted to carbonic acid and considerably
amplified in volume, the relative proportion of nitrogen being lessened.
A part of this gas is allowed to pass away through the pipe already described
communicating with the air, at the commencement of the process of manufacture,
The
instead of being delivered through the pipe leading to the gas holder.
remainder of the mixture is forced back to and through the first retort, the carbonic
acid being again converted to carbonic oxide, and thence to the second oxidizing
retort where the carbonic oxide is again converted into carbonic acid and increased
in volume, and the relative proportion of nitrogen is again considerably reduced.
It will be seen that after a very short time the contents of the system become,
without exterior aid, carbonic oxide, and practically pure carbonic acid the volume
of which is increased every time it passes through the oxidizing retort, the surplus
In order to
so produced passing off continuously to the gas holder and washers.
prevent the presence of nitrogen at the commencement of the process, the whole
system may be charged with carbonic acid gas before commencing. After the

page_text: process has continued for a certain time the metallic oxide in the second retort
becomes reduced to a state approaching metallic, insufficient oxygen remaining in
When this is the
it to oxidize the carbonic oxide coming from the first retort.
case, it is necessary to cease the manufacture, and to close the valves in the
circulating pipes, those communicating with the fan and with the pipe leading to
the open air being opened, and the fan being set in motion, air is passed through
the contents of the trays in the second retort, the oxygen gas re-oxidizing the
metal in the trays and the nitrogen passing away into the open air or being
conducted away and utilized if preferable.
As soon as the re-oxidation of the copper is complete or has proceeded sufficiently
far, the two open valves are closed and the others opened, the circulating blower
is then re-started and the process of manufacture of carbonic acid gas resumed.
The nitrogen gas remaining in the second retort may be blown out through the
pipe communicating with the open air.
Instead of suspending the process of manufacture as described, in order to
re-oxidize the copper in the second retort, it is preferable that the number both
of the first and second retorts should be multiplied so that the manufacture of gas
can be continued without intermission, the alternate use and re-oxidation of the
contents of the second retorts being arranged so as to be progressive, one series
being in action whilst the contents of the other one is in course of being
re-oxidized.
In some cases a regenerator of the well known ordinary construction may be
interposed between the fan and the valve which connects the latter with the second
retort as described, so that the entering air for re-oxidizing the copper becomes
heated by means of the outgoing gas passing to the open air as above described, or
by the products of combustion passing from the furnace to the retorts.
Also, the retorts themselves, (where the manufacture is on a large scale) may
be heated by well known systems of gas firing and regeneration.
The contents of the first retort may be heated by passing air intermittently
through the retort, which is thus heated internally, instead of externally. By
using external heat however the process can be carried on continuously.
By this invention carbonic acid gas is obtained very economically, the process
being simple, and the apparatus being inexpensive, easily worked, and not liable
to get out of order.
Dated this 3rd day of July 1893.
EDWARDS & Co.,
35, Southampton Buildings, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
An Improved Method of and Apparatus for Producing Carbonic
Acid Gas.
We, HOWARD LANE, of Corporation Street, Birmingham, Engineer, and JOHN
PULLMAN, of 17, Greek Street, Soho, in the County of Middlesex, Manufacturer,
do hereby declare the nature of our said invention and in what manner 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 invention relates to a new or improved method of economically and rapidly
obtaining carbonic acid gas and to apparatus to be used in connection with such
method.
The improved process consists substantially in passing atmospheric air which
the apparatus contains at the commencement of the process, through a retort or
chamber containing heated carbon, thus producing carbonic oxide gas, wh.ch is
then passed through a second heated retort or chamber containing a metallic
0

page_text: oxide by which the carbonic oxide is converted into carbonic acid, and is
considerably increased in volume. A part (constituting the surplus) of the carbonic
acid gas thus obtained is passed to a gas holder and washer, and can then be
utilized in any desired way, whilst the remainder (more or less equal to the volume
of the carbonic oxide) is passed back to and through the first retort where it is
again converted to carbonic oxide the latter being returned once more to the
second retort and passed through the heated metallic oxide in the latter, and
being again converted to carbonic acid gas of increased volume, a part of which
is carried off to be used, whilst the remainder again returns to the first retort,
and so on as long as may be desired.
When the metallic oxide becomes reduced to a metallic state by giving up its
oxygen to the carbonic oxide, a current of air (preferably heated) is passed
through it until it has become sufficiently re-oxidized, and the process is then
continued as already described.
It is evident that the details of the apparatus used in the improved process
may be varied more or less and the following description and drawing are
illustrative only of the method of construction and arrangement which we prefer
to use.
The apparatus consists of a vertical retort or chamber a, preferably of fireclay
and lined with a wrought iron tube b. This retort is set in a brickwork chamber c
and is heated by a furnace d of suitable construction. The lower end of the retort
may be open and made to dip into a water pan or vessel e so arranged (as
shewn) that ashes and refuse from the retort may be removed without stopping the
work. The upper end of the retort a is provided with a cover or cap, having a door g
through which the retort can be conveniently charged, an inlet pipe h passing
through the cover and centrally down nearly to the bottom of the retort a.
outlet pipe is also arranged from the top of the retort. The retort is charged,
as required, with charcoal, coke, or other suitable carbonaceous material, upon the
purity of which that of the resulting gas will depend.
An
In a convenient position in the neighbourhood of the retort just described is
arranged a second retort or chamber preferably horizontal, and of cast iron,
wrought iron plates, or other suitable material. This chamber is fitted with a
sufficient number of perforated fire-brick trays l, upon which is placed oxide of
copper or of other suitable metal in a finely divided state.
In order to prevent or reduce the action of the oxide upon the material of which
this retort is made, we preferably interpose asbestos in suitable form between the
oxide and the walls of the retort, and the latter is provided with a suitable
manhole and door at m by which access can be had to its interior, and with an inlet
pipe n entering below the trays I carrying the oxide, and an outlet pipe o above the
the latter. The retort is set in a suitable firebrick chamber p and is heated by
the waste heat from the retort first described, or by other suitable means.
The outlet pipe o from the second retort is connected with the inlet pipe
descending through the centre of the first retort, and the outlet pipe of the latter
is connected with the inlet pipe to the second retort, and in a suitable part of the
circuit of pipes thus formed, preferably in the outlet pipe from the second retort,
is inserted a blowing apparatus r of any suitable kind (such for instance as what is
well known as a "Root's" blower) capable of operating upon hot gases, its object being
to cause the constant circulation of the gases produced, through the different parts
of the apparatus. An ordinary fan s, or other equivalent apparatus for dealing
with large quantities of air is also arranged in connection with the inlet pipe n into
the lower part of the second, or oxidizing, furnace & described, or in other suitable
position, so that when required air can be driven through the inetal upon the trays
for the purpose of re-oxidizing it. A pipe communicating preferably with the
open air is arranged upon the delivery pipe o from the second retort.
Regulating valves are arranged, one u upon this pipe just described, one v upon
the delivery pipe of the fan s, one wo upon the pipe i communicating from the upper
part of the first retort to the lower part of the second retort, and one x upon the
0

page_text: delivery pipe from the upper part of the second retort to the top of the pipe-
descending to the lower part of the first retort, which valves can be opened and
closed according to the different parts of the process which are being carried on.
The circulating pump r and the fans described are driven by steam or any
convenient power.
The process for manufacturing carbouic acid gas by means of apparatus of the.
kind described, is as follows:-
The first retort is filled with carbon, and the trays in the second retort with
copper oxide or scale, or other suitable metallic oxide. The valves on the delivery
from the fan and upon the pipe communicating between the delivery pipe of the
second furnace and the open air, are closed and the other valves opened. The
circulating blower is then set in motion, and both retorts are heated, the first to a
bright red and the second to a low red heat.
The entire system in this condition contains atmospheric air, that is to say a
mixture of nitrogen and oxygen gases.
The oxygen combines with the carbon and is converted to carbonic acid gas in
the lower part of the first retort and as it rises is further converted to carbonic
oxide gas.
The resulting mixture of carbonic oxide and nitrogen gases is passed by the
action of the circulating blower from the upper part of the first retort and into the
lower part of the second (or oxidizing) retort and passing up through the copper
oxide the carbonic oxide becomes converted to carbonic acid and considerably
amplified in volume, the relative proportion of nitrogen being lessened.
A part of the gas is allowed to pass away through the pipe already described
communicating with the air, at the commencement of the process of manufacture,
instead of being delivered through the pipe leading to the gas holder. The
remainder of the mixture is forced back to and through the first retort, the
carbonic acid being again converted to carbonic oxide, and thence to the second
oxidizing retort where the carbonic oxide is again converted into carbonic acid and
increased in volume and the relative proportion of nitrogen is again considerably
reduced.
It will be seen that after a very short time the contents of the system become,
without exterior aid, carbonic oxide, and practically pure carbonic acid, the volume
of which is increased every time it passes through the oxidizing retort, the surplus
so produced passing off continuously to the gas holder and washers. In order to.
prevent the presence of nitrogen at the commencement of the process, the whole
system may be charged with carbonic acid gas before commencing. After the
process has continued for a certain time the metallic oxide in the second retort
becomes reduced to a state approaching metallic, insufficient oxygen remaining in
it to oxidize the carbonic oxide coming from the first retort. When this is the
case, it is necessary to cease the manufacture, and to close the valves in the
circulating pipes, those communicating with the fan and with the pipe leading to
the open air being opened, and the fan being set in motion, air is passed through.
the contents of the trays in the second retort, the oxygen gas re-oxidizing the
metal in the trays and the nitrogen passing away into the open air or being
conducted away and utilized if preferable.
As soon as the re-oxidation of the copper is complete or has proceeded sufficiently
far, the two open valves are closed and the others opened, the circulating blower is.
then re-started and the process of manufacture of carbonic acid gas resumed. The
nitrogen gas remaining in the second retort may be blown out through the pipe
communicating with the open air.
Instead of suspending the process of manufacture as described, in order to.
re-oxidize the copper in the second retort, it is preferable that the number both of
the first and second retorts should be multiplied so that the manufacture of gas can
be continued without intermission, the alternate use and re-oxidation of the contents.
of the second retorts being arranged so as to be progressive, one series being in
action whilst the contents of the other one are in course of being re-oxidized.

page_text: In some cases a regenerator of the well known ordinary construction may be
interposed between the fan and the valve which connects the latter with the second
retort as described, so that the entering air for re-oxidizing the copper becomes
heated by means of the outgoing gas passing to the open air as above described, or
by the products of combustion passing from the furnace to the retorts.
Also, the retorts themselves, (where the manufacture is on a large scale) may be
heated by well known systems of gas firing and regeneration. The contents of the
first retort may be heated by passing air intermittently through the retort, which is
thus heated internally, instead of externally. By using external heat however the
process can be carried on continuously.
By this invention carbonic acid gas is obtained very economically, the process
being simple, and the apparatus being inexpensive, easily worked, and not liable to
get out of order.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The method of producing carbonic acid gas, consisting in first causing air to
pass through a chamber containing heated carbon, thus producing carbonic oxide
gas which is passed through a second heated chamber containing a metallic oxide
by which the carbonic oxide is converted into carbonic acid and is increased in
volume, a part of such carbonic acid being passed to a gas holder, and the
remainder being passed back to and through the first retort where it is again
converted to carbonic oxide which is once more passed through the heated metallic
oxide in the second chamber and again converted to carbonic acid gas of increased
volume, a part of which passes to a gas holder, whilst the remainder returns to the
first retort, and so on as long as may be desired, the metallic oxide in the second
chamber being re-oxidized when necessary by passing air through it, substantially
as described.
2. In the process claimed in Claim 1, the method of charging the whole system
with carbonic acid gas at the commencement of the process, in order to prevent the
presence of nitrogen gas when air is used, substantially as described.
3. The apparatus for carrying on the process claimed in Claim 1, consisting of a
heated retort or chamber a, outlet pipe i, communicating by pipe n with a second
heated retort or chamber k containing metallic oxide, outlet pipe o, circulating
pump r, delivering pipe h communicating with a gas holder or washers, and with the
bottom of the retort or chambers a, air pump or fans, and regulating valves u
and v, w, and a, substantially as described and illustrated.
4. In combination with the apparatus described in Claim 3, the pipe t and
valve u, arranged and operating substantially as and for the purpose described and
illustrated.
5. The use of two or more sets of the apparatus claimed in the first claim, such
sets being operated in succession so that the process of manufacture is continuous,
substantially as described.
Dated this 2011
of Amil 1901
EDWARDS & Co.,
65 & 66, Chancery Lane, London, Agents for the Applicants.