Improvements in the Production of Carbonic Acid Gas.
Year: 1892

page_text: Cate of Application, 12th Aug., 1892
Complete Specification Left, 12th May, 1893--Accepted, 22nd July, 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by JOHANN HEINRICH CARL BEHNKE, Chemist,
and THE CHEMISCHE FABRIK in Billwärder, vorm. HELL and STHAMER,
A. G., both of Billwärder on the Bille, in the Empire of Germany.]
Improvements in the Production of Carbonic Acid Gas.
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 improvements in obtaining by means of alkaline
carbonate, pure carbonic acid gas from the products of combustion and from the
gases given off from lime-kilns and other carbonic acid gas producing kilns. In
the production of pure carbonic acid gas from the gases of combustion of charcoal,
coke and the like and from the gases of lime kilns and other carbonic acid pro-
ducing kilns by allowing water to absorb under pressure the carbonic acid
containing gases it is assumed that the gases to be employed are tolerably rich
in CO, as with respect to absorption they are submitted to the Henry-Dalton-Law
process. But the apparatus used in carrying out this process must be of a very
strong description as for advantageous working a high pressure is required. In
the process forming the subject of the present invention it is a matter of com-
parative indifference what amount of carbonic acid is contained in the gases,
and the apparatus necessary for carrying out this process may be made of light
construction but gases rich in carbonic acid are of course more advantageously
worked than gases which are poor.
The process is based on the fact, that carbonic acid gas mixed with other gases
is absorbed by a solution of alkaline carbonate and expelled again by heating the
solution of bicarbonate. But this method has been evolved by the inventor from
the idea and principle that it depends not so much on the quality (richness in
carbonic acid gas) of the gases employed but rather on the longer and enforced
presence of the gases in the apparatus and on a more frequently repeated intimate
contact of the same with the solution of alkaline carbonate.
The driving off of the carbonic acid gas from the solution of bicarbonate, or the
decomposition of the same has been effected hitherto in practice in an extremely
dis-advantageous incomplete and imperfect manner, special apparatus may however
be employed in obtaining carbonic acid gas, and which may be used for carrying
out the present process in an advantageous manner I shall now proceed to describe
the same in connection with the said apparatus.
A steam boiler of suitable construction the rear end of which carries a column
similar in construction to Savalle's distilling column, and which may be called a
lye-steam boiler is employed a solution of alkaline bicarbonate (or carbonate) is
heated therein by direct fire heat or by any waste heat to the boiling point and
maintained at this temperature.
The carbonic acid gas thus freed in the said lye-steam boiler is caused to pass
through superposed finely perforated partitions in the said column communicating
one with another by one or more overflow-pipes each dipping with its lower end
into recesses or cups of a respective lower perforated partition, and it then escapes
into a gas cooler connected to a water trap directly through a charcoal-filter and
from thence to a gasometer for storage or to the place of consumption. The waste
water of the cooler is led in the usual way to a pump which serves to maintain
always the same degree of saturation in the solution employed. The products of
combustion after having heated the said lye-steam-boiler pass to a superheater

page_text: connected therewith and preferably arranged in the flues of the steam boiler, and
thence to an evaporator, after having thus given off the largest part of their heat,
are not conveyed to the chimney but are sucked in by a force pump or a high
pressure blast through two washers which are continuously fed with cold water,
whence the said products are forced through a second cooler into the lower boiler of a
second column, the latter being provided in the same manner as the first column on
the lye-steam-engine with a certain number of horizontal finely perforated partitions
communicating with each other by overflow-pipes as aforesaid. The carbonic acid
gas is absorbed by the solution of alkaline carbonate the second column apparatus
being charged and fed with this liquid. The fixed gases escape, after having
passed through all the superposed perforated partitions of this column into the
open air or they are turned through a gas-meter or Leibegs potash bulbs to control
them. The solution of bicarbonate formed in this column apparatus is continuously
discharged by a pump upon the highest perforated partition of the column of the
lye-steam-boiler and passes in a heated state and freed from a part of the carbonic
acid gas into the said lye-boiler. The boiling solution of alkaline bicarbonate or
alkaline carbonate or alkaline sesquicarbonate contained therein flows, as mentioned,
from the front end of the lye-steam-boiler into a superheater and thence into an
evaporator. The latter is preferably provided with an agitator, which has for its
purpose to assist the expulsion of the carbonic acid gas from the highly heated lye
on the entrance of the latter into the evaporator and thus to aid the quick removal
of the same.
The temperature of the highly heated lye entering the evaporator under a
pressure which corresponds to the heat, falls immediately to the boiling point,
and the pressure nearly to one atmosphere, while the suddenly freed steam together
with the carbonic acid gas contained still in the lye of the alkaline carbonate
and mechanically or chemically bound as alkaline bicarbonate and sesquicarbonate,
passes through another cooler to one of the upper perforated partitions of the
column on the lye-boiler whence the carbonic acid gas flows, to a gasometer. The
lye of the alkaline carbonate remaining in the said evaporator passes through a
serpentine coil to one of the lye-pumps which forces the lye through a cooler upon
the upper perforated bottom of the second column in order to cool the liquid as
completely as possible.
The whole of the apparatus is controlled by means of suitable valves or other
devices in such a manner, that during the carrying out of the process the level
of the liquid lye is in all the parts of the apparatus the same i.e. that the said
serpentine is always completely charged so that a uniform circulation of the said
lyes though having a different yield in carbonic acid gas, will take place in all
the apparatus.
An important advantage in this new process consists in the fact, that coke-ovens
lye-reservoirs &c. may entirely be dispensed with.
Dated this 20th
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Production of Carbonic Acid Gas.
1, 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 improvements in obtaining by means of alkaline
carbonate, pure carbonic acid gas from the products of combustion and from the

page_text: gases given off from lime kilns and other carbonic acid gas producing kilns. In
the production of pure carbonic acid gas from the gases of combustion of charcoal
coke and the like and from the gases of lime-kilns and other carbonic acid producing
kilns by allowing water to absorb under pressure the carbonic acid containing gases
it is assumed that the gases to be employed are tolerably rich in CO, as with
respect to absorption they are submitted to the Henry-Dalten-Law process. But
the apparatus used in carrying out this process must be of a very strong description
as for advantageous working a high pressure is required. In the process forming
the subject of the present invention it is a matter of comparative indifference what
amount of carbonic acid is contained in the gases, and the apparatus necessary
for carrying out this process may be made of light construction but gases rich
in carbonic acid are of course more advantageously worked than gases which
are poor.
The improved process forming the subject of the present invention is based on
the fact that the carbonic acid gas mixed with other gases is absorbed by a solution
of alkaline carbonate and expelled or removed again by heating the solution of
bicarbonate thus formed. For this purpose the gases containing carbonic-acid are
brought in close contact with the solution of alkaline carbonate by distributing the
solution in a determined thickness over superposed and finely perforated partitions,
through the perforations of which the carbonic acid gas is caused to pass upwards
under pressure so as to secure an increasing saturation of the downward running
solution of alkaline carbonate under gradually increasing gas-pressure.
In order to separate or remove the carbonic acid the bi-carbonate solution obtained
by the saturation of the mono-carbonate solution with carbonic acid is made to run
continuously into the top of a column provided also with superposed perforated
partitions and placed upon and communicating with a suitable boiler so that the
vapours produced by boiling the bicarbonate solution and the carbonic-acid freed
thereby are caused to pass from below up to the top through the perforations of
the partitions and through the layers of bi-carbonate solution resting upon the said
partitions at a fixed height.
The vapours passing through these layers of bicarbonate solution resting upon
the partitions which communicate with one another by means of overflow-pipes will
thereby be condensed, whilst the carbonic acid escapes from the upper part of the
said column into a suitable gas holder under a pressure somewhat higher than the
atmospheric pressure; while in the steam-boiler and in the lower part of the column
there is a higher pressure corresponding to the sum of the liquid-layers upon the
several partitions. By these means the bicarbonate solution continuously entering
the top of the column in a cold state, will step-by-step become heated on its way
over and through the said partitions so that the solution has already delivered or
separated greater part of the absorbed carbonic-acid as soon as the solution which
is in a state for allowing the application of a greater heat, enters the boiler, by
which an effectual realization of the heat is secured. The solution of alkaline
carbonate before it is cooled and used again in the saturating-process as mono-
carbonate solution is conducted into a closed reservoir provided with an agitator,
which serves both to assist the cooling and in the separation or removal of the
carbonic acid from the solution. The carbonic acid thus released may be led
directly through a suitable cooler into the gas-holder. By again using the remaining
and cooled mono-carbonate solution for the saturating process a complete cycle is
formed owing to which the cost of the whole process compared with that of the
processes hitherto employed is considerably reduced.
For carrying out the present process in an advantageous manner a special
apparatus is employed and I shall now proceed to describe the same in connection
with the said process and with reference to the accompanying drawing.
The gases containing carbonic acid are forced through the cooler J and pipes c
into the vessel K' above which is erected the column or tower K divided into a
series of compartments by means of superposed and perforated partitions k. The

page_text: mono-carbonate solution forced by means of the pump E through the cooler N and
pipes i into the upper part of the column K is distributed over the perforated
partitions successively from above by means of overflow-pipes k¹ preferably tapered
towards their lower ends and dipping into cups, or by lateral tubes n or by both.
The mono-carbonate solution as it passes over the numerous perforated partitions k
is brought into close contact with the gases containing carbonic acid, or with the
carbonic acid coming from beneath, that is to say, in a direction opposite to that
of the gases passing through the perforations of the partitions so that the solution
is fully saturated and passes into the vessel K' as a bi-carbonate solution. The
permanent gases not absorbed in traversing the layers of solution upon the partitions k,
may escape into the atmosphere by means of a suitable valve and pipe.d. The
number and the size of the conical perforations of the said partitions are to be
chosen in such a manner that these perforations with the aid of the gas-pressure in
the vessel K¹ can retain the layer of liquid, upon the respective partition. It is
evident that in consequence of this arrangement the gas-pressure gradually decreases
in the column K in upward direction and that therefore the pressure in the upper-
most compartment according to the position of the weight of the regulating valve a
can be controlled at will so that the pressure at that part of the apparatus is equal
or nearly equal to the atmospheric pressure. The great number of perforations in
the partitions allow a very close or intimate contact of the gases containing carbonic
acid with the solution of alkaline carbonate thereby effecting a complete absorption
of the carbonic acid, the said absorption being greater, the greater the difference
of the pressure in the vessel K', and in the uppermost compartment of column K.
In the vessel K¹ is preferably arranged a partition u perforated below the level
of the liquid in order to distribute the carbonic acid gases entering through the
pipe cinto minute jets within the alkaline solution so that at this stage as
circumstances may require, a part of the carbonic acid may be absorbed by the
solution of alkaline carbonate through which the gases pass.
The bi-carbonate solution, collected in the vessel K' in the manner above
described is conveyed by means of a pump F through the pipe f into the uppermost
⚫ compartment of a column or tower A similar in construction to the column K and
provided also with perferated partitions a and over-flow pipes a' a². The column A
is fixed directly upon the boiler A' so that the latter and the said column
communicate with each other. The size and number of the perforations in the
said partitions correspond to the pressure under which the boiling of the solution
takes place. The transformation of the bi-carbonate solution saturated with
carbonic acid into mono-carbonate solution and the removal of the carbonic acid
by heating is performed in this apparatus under a pressure decreasing from the
bottom to the top of the column A so that the solution pumped into the uppermost
compartment of A is successively heated on its downward way to the boiler. The
carbonic acid thereby freed in the said column is caused to pass through the
superposed finely perforated partitions a, and thence escaping through pipes aº into
cooler B and filter C to the gas-holder D for storage or direct to the place of
consumption.
In this column A, also a different pressure exists in the lower and upper part,
which difference of pressure corresponds to the sum of the heights of liquid-layers,
on the partitions.
The boiled mono-carbonate alkali solution is led through the pipe b provided with
a regulating-valve &¹ into the reservoir H the said reservoir being provided with an
agitator H. By agitating the solution the mechanically and loosely bound
carbonic acid will be freed, which passes through pipes a cooler L direct into the
gas-holder D. The mono-carbonate-solution remaining in the reservoir H is drawn
by suction through the pipe into the coil M by means of a pump E from whence
it is forced, as already stated above, through pipes and cooler N into the
uppermost compartment of the absorption-column K in order to commence its cycle
again as described.

page_text: The over-flow pipes a' and the lateral connecting pipes a² must be wider at their
upper that at their lower ends but the outlet-opening of these pipes.must have such
a diameter that the maximum of liquid supplied through the pipe f may pass or
flow from one compartment of the column into the next one and through the
siphon-pipe a into the boiler without covering or closing the inlet-openings of the
over-flow and connecting pipes, so that the height of the liquid-layers depends
only on the pressure-difference in the column. For regulating the pressure in the
single compartments of the column A the boiler A' is provided with a vertical
pipe y and communicating with the said compartments by means of branch-pipes y
provided with regulating-valves y¹. The pressure in the compartments of the
column K may be regulated in a similar manner. Suitaby arranged manometers
or pressure-gauges, water-gauges and the like, allow the observation of the actions
performed in the apparatus, so that a sufficient guarantee is given for regular and
correct working.
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 :—
1. A process for the production of pure carbonic acid from products of combustion
and from the gases expelled from lime-kilns and other carbonic acid gas producing
kilns by means of alkali solution, consisting in forcing the gases containing carbonic
acid during the saturating-process through layers of mono-carbonate solution
resting upon superposed perforated partitions under a pressure successively
decreasing in upward direction.
2. In the process above described the introduction of the bi-carbonate solution
thus obtained in the uppermost compartment of a second column provided also with
superposed perforated partitions, through which the carbonic acid freed from the
saturated bi-carbonate solution by boiling together with steam or vapours is caused
to pass under a pressure decreasing gradually in upward direction so that the
carbonic acid may collect in the upper part of the column and escape in a cooled
state into a gas-holder.
3. In the process above described the conducting of the boiled solution, before it
is used again as mono-carbonate solution in the saturating-column into a closed
reservoir provided with an agitator for separating or removing the mechanically or
loosely bound carbonic-acid which is thus enabled to escape into the gas-holder,
substantially as and for the purpose set forth.
4. In an apparatus for the production of carbonic acid with the aid of a solution
of an alkaline carbonate, the combination of a column K provided with superposed
perforated partitions communicating by over-flow pipes one with another and
adapted for the saturating-process as set forth, a vessel K below the column K for
collecting the saturated bi-carbonate solution, a column A similar in construction
to columu K in which the bi-carbonate solution is distributed from above and led
to a boiler A¹ for expelling the carbonic-acid under the action of heat, and a closed
vessel H provided with an agitator H' all connected and communicating one with
another, substantially in the manner and for the purpose set forth.
5. In the production of carbonic acid with the aid of an alkaline solution, the
application and use of a column provided with superposed perforated partitions
through which, for the purpose of absorbing the carbonic acid from gases containing
the same, the latter are forced to pass from below to above under a pressure
successively decreasing in upward direction, while the alkaline solution is distributedł
from above on the perforated partitions designed to hold the solution in layers of
a given thickness, substantially as and for the purpose set forth.
6. In the production of carbonic acid with the aid of an alkaline solution, the
application and use of a column provided with superposed perforated partitions
over which are distributed from above uniform layers of a bi-carbonate solution, in
combination, with a boiler in which the bi-carbonate solution is collected from the
column and heated for the purpose of expelling the carbonic acid absorbed by the

page_text: same, the latter being forced through the layers of bi-carbonate solution on the
perforated partitions under a pressure successively decreasing in upward direction,
substantially as set forth.
Dated this 12th day of May 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.