Improvements in Means for Obtaining Carbonic Acid from Gaseous Mixtures.
Year: 1896

page_text: Date of Application, 13th Jan., 1896
Complete Specification Left, 12th Oct., 1898-Accepted, 13th. Jan., 1897
PROVISIONAL SPECIFICATION.
Improvements in Means for Obtaining Carbonic Acid from Gaseous
Mixtures.
1, WILHELM RAYDT, of No. 195 Silberburgstrasse, Stuttgart, Würtemburg,
in the Empire of Germany, Doctor of Philosophy, do hereby declare the nature
of this invention to be as follows:-
In the Specification of former Application No. 13456%, carbonic acid is
obtained from gases containing such acid by the aid of dry solid substances
capable of absorbing carbonic acid (such as monocarbonates); such substances being
constantly left in the apparatus, both for the purpose of absorption, and for
distilling the carbonic acid absorbed. This object is attained by causing the said
gases, containing carbonic acid, to act upon the dry and solid absorbing agents
(or monocarbonates) in the presence of as much moisture as is necessary for the
completion of the chemical carbonic acid combination. By such means the dry
absorbing agents (or monocarbonate) is wholly or partly converted into a solid
carbonate of a higher order (a bicarbonate), whereupon the carbonic acid absorbed
is wholly or partly distilled off by the action of heat and may be collected
separately.
In the apparatus described in the former specification above referred to, the
requisite moisture is supplied in the form of either water or steam, preferably
by being conducted through perforated pipes, arranged above layers of absorbing
material.
Now it has been found in the practical performance of this invention that both
the process and the apparatus described in the previous specification are capable
of still further improvement.
By employing water in the distilled condition, the carbonic-acid-absorbing
substances are effectively protected from the introduction into them of the
impurities which non-distilled water invariably contains and which, as time goes
on, are apt to collect in the said absorbing agents in quantities calculated to render
those agents unavailable for further use for the object stated, so that the charge
of absorbing material has to be renewed. The employment of distilled water
obviates this drawback and assists in rendering the absorbing agents after they
have been once introduced into the apparatus, serviceable for an almost indefinite
period of time without involving any break or disturbance in the course of the
operation.
The process described in the said fermer specification may further with
conspicuous advantage be modified also by supplying the required moisture to the
mono-carbonate,-with a view to the formation of bi-carbonate,-in the form of
steam, so as to admit of as uniform a distribution of the moisture as practicable.
The best way to accomplish this is to saturate the gases which contain carbonic
acid, and which are treated for the purpose of extracting the same (they being in
most cases and for general practical purposes hot gases or products of combustion,
derived from furnaces and heating apparatus generally) with a predetermined
quantity of water at a temperature of say 70° Centigrade, after which the gas
thus impregnated with moisture is admitted to the charge of monocarbonate with
a view to its conversion into bicarbonate.
The object just stated is not attainable by means of the apparatus described in

page_text: the said former specification by simply sending the gases containing carbonic acid
through water and then conducting them to the absorption chamber of the said
apparatus. And the reason is the necessity, on economical grounds, and for the
better utilization of the gas, of causing it to pass through a number of layers of
monocarbonate in succession, so as to derive as full advantage as possible from its
employment. This circumstance has been duly taken into account in the con-
struction of my improved apparatus. Besides in such an arrangement, the first
layers will have more moisture supplied to them than they require, while the
supply to the layers traversed last would be likely to prove insufficient. The
remedy suggested for this state of things would consist in bringing each layer of
monocarbonate into contact with only just that amount of humidity which is
necessary to bring about the chemical action upon which the absorption of carbonic
acid depends; and this is best performed by modifying the apparatus described in
the aforesaid former specification in this particular, that for each individual layer
of monocarbonate a separate layer of porous material is provided which may be
impregnated with water in lieu of the monocarbonate layer itself. This porous
layer or bed is, through suitable tubing, moistened with water to the extent
necessary for the formation of monocarbonate from the corresponding layer. The
hot gases (raised to a temperature of say 70° Centigrade) which contain the
carbonic acid and are sent through the said porous layers, take up, on their way,
the moisture contained in such layers and transmit it to the corresponding mono-
carbonate layers, so that the required quantities of moisture may act upon all
particles or molecules of monocarbonate in a perfectly uniform and reliable manner,
and that a practically complete conversion is ensured.
As the apparatus has to be heated to enable the carbonic acid, which has been
absorbed, to be extracted, it is advisable to employ as resistant materials as possible
in forming the porous layers, that is to say materials capable of retaining their
porosity unaltered, no matter to what extent they are humidified or at what
temperature they may be used; asbestos, silicious sinter, or small coke being
suitable substances.
Owing to this arrangement, the unequal distribution of the moisture in the
mouocarbonate mass, as well as the formation of channels, under the action of
water supplied either in the form of spray, or produced by the condensation of
steam (through which channels the gases would, of course, make their way in
preference) is prevented; so that the said gases are compelled to act in a reliable
manner upon the whole of the mass, in all parts of which the moisture is thus
evenly diffused.
In a modification of the apparatus described in the said Specification
No. 13456, the layers of porous material are situated below the water jets of the
apparatus which is the same as that described in the said previous specification.
It is advisable, in using this arrangement, to remove the lowermost monocarbonate
layer which the current of gas, containing carbonic acid, upon entering, meets
first (that is to say, without having previously come into contact with a humid
porous layer), and to place such monocarbonate layer above the uppermost water
jet; as, failing this, the gas current would, for want of moisture, remain practically
inoperative. The apparatus is worked very much like the arrangement described
in the said previous specification, the only difference being that the requisite
quantities of water which are supplied by the jets are taken up, not by the mono-
carbonate layers, but by the layers of porous material. The rising current of gas,
containing carbonic acid, has therefore to pass first through a porous layer, which
is soaked with the quantity of moisture requisite for enabling the monocarbonate
spread above, to absorb carbonic acid; such moisture having been supplied by the
said jet or pipe. The gas current, heated to about 70° Centigrade, takes up the
moisture from the porous layer and transmits it to the next following layer o
monocarbonate by which such moisture is again absorbed along with the prope
quantity of carbonic acid, in which process a formation of bicarbonate takes place
The gas current, as it passes on, traverses a second moist porous layer, and upo

page_text: this becoming charged with hiimidity,, passes on to the next layer of mono-
carbonate, where the same action takes place as in the preceding layer; and so
forth.
The heating pipe arrangement may be such that the pipes located within the
apparatus, are connected together by chambers which will be found a very
satisfactory substitute for the system of heating pipes described in the said former
Specification No. 13456", where such system really assumes the shape of one single
or continuous pipe.
In the arrangement described in the said previous specification, and in the process
and apparatus above referred to, a further convenient modification may be made by
conveying the carbonic acid gas into the apparatus from above, through a pipe,
and discharging such gas from below through another pipe. In this case, the
apparatus forming the subject of the aforesaid prior specification need not be'
further modified beyond being provided with the pipe at the top and the pipe at
the lower part.
The layer of material which is to absorb carbonic acid and which, as has been
stated above, lies at the top, will have to be again brought to the bottom so that
the gases, which are here admitted from above, may meet first a comparatively
extensive sheet or layer of moist porous material, and may not reach the first
absorbing layer until after having done so.
It will be understood that, as has been above explained in reference to the prior
specification herein before referred to the operation may be rendered continuous by'
the employment of a number of apparatus connected with each other and fitted up
exactly in the same manner as the apparatus above described.
Dated this 13th day of January 1806
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Means for Obtaining Carbonic Acid from Gaseous
Mixtures.
I, WILHELM RAYDT, of No. 195 Silberburgstrasse, Stuttgart, Wurtemburg,
in the Empire of Germany, Doctor of Philosophy, 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 :-
In the Specification of former Application No. 13456%, carbonic acid.is
obtained from gases containing such.acid by the aid of dry solid substances capable
of absorbing carbonic acid (such as monocarbonates); such substances being
constantly left in the apparatus, both for the purpose of absorption, and for
distilling the carboric acid absorbed. This object is attained by causing the said
gases, containing carbonic acid, to act upon the dry and solid absorbing agents
(or monocarbonates) in the presence of as much moisture as is necessary for the
completion of the chemical carbonic-acid combination. By such means the dry
absorbing agents (or monocarbonate) is wholly or partly converted into a solid
carbonate of a higher order (a bicarbonate), whereupon the carbonic acid absorbed
is wholly or partly distilled off by the action of heat and may be collected
separately.
In the apparatus described in the former specification above referred to, the
requisite moisture is supplied in the form of either water or steam, preferably
by being conducted through perforated pipes arranged above layers of absorbing
material.

page_text: Now it has been found in the practical performance of this invention that both
the process and the apparatus described in the previous specification are capable
of still further improvement.
By employing water in, the distilled condition, the carbonic-acid-absorbing
substances are effectively protected from the introduction into them of the
impurities which non-distilled water invariably contains and which, as time goes
on, are apt to collect in the said absorbing agents in quantities calculated to render.
those agents unavailable for further use for the object stated, so that the charge
of absorbing material has to be renewed. The employment of distilled water
obviates this drawback and assists in rendering the absorbing agents after they.
have been once introduced into the apparatus, serviceable for an almost indefinite
period of time without involving any break or disturbance in the course of 'the'
operation..
The process described in the said former specification may further with
conspicuous advantage be modified also by supplying the required moisture to the
mono-carbonate, with a view to the formation of bicarbonate,-in the form of
steam, so as to admit of as uniform a distribution of the moisture as practicable.
The best way to accomplish this is to saturate the gases which contain carbonic
acid, and which are treated for the purpose of extracting the same (they being in
most cases and for general practical purposes hot gases or products of combustion,
derived from furnaces and heating apparatus generally) with a predetermined
quantity of water at a temperature of say 70° Centigrade, after which the gas thus
impregnated with moisture is admitted to the charge of monocarbonate with a view
to its conversion into bicarbonate.
The object just stated is not attainable by means of the apparatus described in
the said former specification by simply sending the gases containing carbonic acid
through water and then conducting them to the absorption chamber of the said
apparatus. And the reason is the necessity, on economical grounds, and for the
better utilization of the gas, of causing it to pass through a number of layers of
monocarbonate in succession, so as to derive as full advantage as possible from its
employment. This circunstance has been duly taken into account in the
construction of my improved apparatus. Besides, in such an arrangement, the
first layers will have more moisture supplied to them than they require, while
the supply to the layers traversed last would be likely to prove insufficient. The
remedy suggested for this state of things would consist in bringing each layer of
monocarbonate into contact with only just that amount of humidity which is
necessary to bring about the chemical action upon which the absorption of carbonic
acid depends; and this is best performed by modifying the apparatus described in
the aforesaid former specification in this particular, that for each individual layer
of monocarbonate a separate layer of porous material is provided which may be
impregnated with water in lieu of the monocarbonate layer itself. This porous
layer or bed is, through suitable tubing, moistened with water to the extent
necessary for the formation of monocarbonate from the corresponding layer. The
hot gases (raised to a temperature of say 70° Centigrade) which contain the
carbonic acid and are sent through the said porous layers, take up, on their way,
the moisture contained in such layers and transmit it to the corresponding mono-
carbonate layers, so that the required quantities of moisture may act upon all
particles or molecules of monocarbonate in, a perfectly uniform and reliable
manner, and that a practically complete conversion is ensured.
As the apparatus has to be heated to enable the carbonic acid, which has been
absorbed, to be extracted, it is. advisable to employ as resistant materials as possible
in forming the porous layers, that is to say materials capable of retaining their
porosity unaltered, no matter to what extent they are humidified or at what
temperature they may be used; asbestos, silicious sinter, or small coke being
suitable substances.
Owing to this arrangement, the unequal distribution of the moisture in the mono-
carbonate mass, as well as the formation of channels, under the action of water

page_text: supplied either in the form of spray, or produced by the condensation of steam
(through which channels the gases would, of course, make their way in preference)
is prevented; so that the said gases are compelled to act in a reliable manner
upon the whole of the mass, in all parts of which the moisture is thus evenly
diffused.
Figure 1 of the accompanying drawing illustrates the construction of the
apparatus described in the said Specification No. 13456, modified in the manner
just stated, and
Figure 2 a still further modification.
As shown in Figure 1 the layers s'of porous material are situated below the
water jets b of the apparatus which is the same as that described in the said previous
specification. It is advisable, in using this arrangement, to remove the lowermost
monocarbonate layer which the current of gas, containing carbonic acid, upon
entering, meets first (that is to say, without having previously come into contact
with a humid porous layer such as s) and to place such monocarbonate layer above
the uppermost water jet b, as, failing this, the gas current would, for want of
moisture, remain practically inoperative. The apparatus is worked very much like
the arrangement described in the said previous specification, the only difference
being that the requisite quantities of water which are supplied by the jets bare
taken up, not by the monocarbonate layers, but by the layers s of porous material.
The rising current of gas, containing carbonic acid, has therefore to pass first
through a porous layers, which is soaked with the quantity of moisture requisite
for enabling the monocarbonate a, spread above, to absorb carbonic acid; such
moisture having been supplied by the said jet or pipe b. The gas current, heated
to about 70° Centigrade, takes up the moisture from the porous layer and transmits
it to the next following layer of monocarbonate a by which such moisture is again
absorbed along with the proper quantity of carbonic acid, in which process a
formation of bicarbonate takes place. The gas current, as it passes on, traverses
a second moist porous layer, and upon this becoming charged with humidity, passes
on to the next layer of monocarbonate, where the same action takes place as in the
preceding layer; and so forth.
The heating pipe arrangement c may be such that the pipes c, located within the
apparatus, are connected together by chambers such as e, which will be found a
very satisfactory substitute for the system of heating pipes described in the said
former specification where such system really assumes the shape of oue single or
continuous pipe.
In the arrangement described in the said previous specification, and in the
process and apparatus above referred to, a further convenient modification may be
made by conveying the carbonic acid gas into the apparatus from above, through a
pipe h, and discharging such gas from below through another pipe g. In this case
the apparatus forming the subject of the aforesaid prior specification need not be
further modified beyond being provided with the pipe h at the top and the pipe g
at the lower part.
It will be seen from Figure 2 however that the layer of material which is to
absorb carbonic acid and which, as has been stated above, lies at the top, will have
to be again brought to the bottom so that the gases, which are here admitted from
above, may meet first a comparatively extensive sheet or layers of moist porous
material, and may not reach the first absorbing layer a until after having done so.
The porous and resistant material, such as asbestos coke, silicious siuter, and the
like is carried upon hurdles or frames. These hurdles or frames, may consist of
wire gauze, perforated sheets, grates or the like of metal or other material, upon
which the said porous material is spread. The layers of material may be of a
thickness of two inches more or less. If the perforations or interstices of the
said wire gauze, perforated sheets, grates or the like are too large, it is preferable,
firstly to cover these hurdles with a permeable fabric such as a fabric woven of
asbestos and then to spread over this cover the said layer of porous material.
It will be understood that, as has been above explained in reference to the prior

page_text: specification herein before referred to the operation may be rendered continuous by
the employment of a number of apparatus connected with each other and fitted up
exactly in the same manner as the apparatus above described.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. In carrying out the process referred to in the first claim of Patent
No. 13456% the employment of distilled water which is conducted to the carbonic
acid absorbing agent (or monocarbonate) for the purpose of imparting thereto the
moisture requisite for the absorption of carbonic acid; the object of this method
of operation being to avoid incorporating in the said absorbing agent or mono-
carbonate any foreign bodies, apt to prove injurious to such absorbing agent in the
further stages of operation; and also to retain the monocarbonate unaltered so
that it may be employed over and over again for the same purpose.
2. A modification of the process referred to in the first claim of Patent 13456%,
consisting in impregnating the carbonic acid gases to be treated with the moisture
requisite for the absorption of carbonic acid, by mixing them with adequate amounts
of steam, prior to conducting them to the carbonic acid absorbing agent (or mono-
carbonate), with a view to causing the moisture to exercise a uniform action upon
the said absorbing agent or monocarbonate and thereby also, consequently, bringing
about a more uniform and thorough absorption of carbonic acid; whereupon the
carbonic acid thus absorbed is, by the action of beat, wholly or partly eliminated
and collected in the pure condition.
3. In the processes referred to in the second claim, mixing the carbonic acid gas
with the requisite amount of moisture by impregnating porous substances possessing
a sufficient power of resistance such as asbestos, silicious sinter, or small coke, with
the requisite amount of water, and by conducting the carbonic acid gases, heated to
about 70° Centigrade, previous to their passage through the carbonic acid
absorbing agents for providing them with the requisite quantity of moisture,
through the moistened porous mass, and only sending them through the mono-
carbonate after that, so as to obviate the necessity of directly humidifying the
monocarbonate itself..
4. The process described in Patent 13456%, or in Claims .1 to 3 above but
carried out in such manner that the carbonic acid gases are admitted into the
absorption apparatus from above and discharged from the lower parts of the same.
5. The form of apparatus suited to the performance of the process referred to in
the third claim (in accordance with the second claim of 134569) mainly con-
sisting in the provision of hurdles or frames each carrying porous and sufficiently
resistant material, such as asbestos, silicious sinter, small coke, or the like, such
as s, in combination with carbonic acid absorbing agents, spread as at a; the
arrangement being such that water issuing from perforated pipes such as b,
descends upon the porous material and is conducted thereby through the gas-
currents traversing the apparatus, after which it is conveyed to the corresponding
frames carrying absorbing material, in the condition of steam.
6. The apparatus referred to in the said Patent 1345605 or in Claim 5 above,
so arranged that the carbonic acid gases are admitted to the absorption apparatus
from the top while the said gases are discharged from below.
7. The combination of apparatus as referred to in the fifth and sixth claims of
the present application in the like manner as characterized in the third claim of
Patent 1345695.
Dated this 1041
1000
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.