Improvements in Process for Production of Carbonic Acid.
Year: 1891

page_text: Dat: of Application, 6th June, 1891-Accepted, 1st Aug., 1891
COMPLETE SPECIFICATION.
Improvements in Process for Production of Carbonic Acid.
Dr. EDWARD LUHMANN of Andernach on Rhine Chemist 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:-
The process now in use for the production of carbonic acid from bicarbonate
alkalies has so far up to the present time not been practical on a commercial
scale in consequence of the prolonged time necessary for the boiling of the
bicarbonate solution whereby the decomposition is not only rendered incomplete
as a rule but becomes impure by continuous or repeated use.
It is probable that the complete decomposition of the bicarbonate alkalies is
depending upon a certain concentration of same and it also appears that the
decomposition of the residue of the alkali bicarbonates takes place in a shorter
time and more completely when same is kept under low pressure with powerful
production of steam.
Since a large amount of heat is necessary for the boiling of the bicarbonate
alkali solution and since further it is necessary to administer the carbonic acid
required for the ulterior regeneration of the mono-carbonate alkali solution
formed during the decomposition into bicarbonate alkali solution the material
used for heating purposes according to the present invention is coke which is
practically free of oxide of carbon and of hydro carbons. According to same
the combustion gases which are rich in carbonic gases are brought to the mono
carbonate of soda solution after having however been washed and cooled and
the resulting bicarbonate of soda solution becomes heated boiled and decomposed
first of all by the steam then being transformed into mono-carbonate alkali
solution by the partial extraction of carbonic acid whilst the residue solution is
finally and completely decomposed under steam in the solution boiler.
The main points in this process are that the final decomposition of the mono
carbonate alkali solution takes place under steam in the solution boiler and that
the coke is used for the double purpose of producing the necessary carbonic acid
and as heating material and that at the same time the necessary concentration of
the solution accompanied by a powerful creation of steam which carries away with
it the carbonic acid is attained.
The apparatus employed in the process is represented in the accompanying
drawing.
"a" is the solution boiler under which a coke furnace is adapted. This furnace
is provided at its bottom part with a pipe c¹ through which the combustion gases
are conveyed to a washing and cooling apparatus "." The heated mono-carbonate
alkali solution contained in the boiler, which however is not yet completely
decomposed, passes by means of a pressure created therein to a cooling apparatus
connected with the boiler by means of the pipe "" and from this finds its way to
the scrubber "" in passing through the pipe . This scrubber is filled with large
pieces of suitable material so that the solution as it runs over these pieces has to
pass over large surfaces. At the same time the combustion gases emanating from
the coke furnace and which have been passed through the washing and cooling
apparatus "c" and which are extremely rich in carbonic acid are made to enter
the scrubber at the lower part of same by means of the pipe 1 on which a blower
is inserted. The consequence of this arrangement is that the carbonic acid
contained in the combustion gases ascending the scrubber are brought into intimate
contact with the solution running down over the material contained in the scrubber
and that same absorbs these gases freely in forming bicarbonate alkali solutions
which are collected in the lower part of the scrubber.

page_text: The bicarbonate alkali solution produced as explained is carried to vat n by
means of the pipe n' whence it is taken up by pump "p" and carried to the boiling
vessel by means of the pipe n². The bottom of this vesso ovided with a
series of perforated pipes which are in communication with the of the solution
boiler "a" by means of the pipe "," so that the steam of this boiler which is
saturated with carbonic acid penetrates into the bicarbonate alkali solution
contained in the vessel "" heating same to a great extent and thus producing
carbonic gas which escapes through the pipe "."
35
any water
The residue solution found in the vessel "k" after the ebullition, is mono
carbonate alkali solution which passes into the vat t and is taken up from there by
means of pump "2" and pipes "e" "el" to be brought back to the solution
boiler « " from which it is again used as described, the whole forming a continuous
circle or process. The carbonic acid which emanates from pipe passes through a
cooler "" afterwards reaching condensing pot "s" where it is freed from
and is collected in a gasometer of the usual description. The cooler 2 is supplied
from the water tank w¹ by means of pipe w³. A similar tank " 20 supplies the
cooling water to the washing apparatus c as well as through the solution cooler .
The condensing water from the condensing pot s is brought back to vat t so as to
maintain the concentration of the solution constant and thus avoid the possible.
blocking up of the pipes.
"
Having now particularly described and ascertained the nature of my invention
and in what way it has to be put into practice I claim.
1. A process for the production of carbonic acid from bicarbonate alkalies in
which the complete decomposition and concentration of the mono-carbonate alkali
solution is obtained with simultaneous production of steam in the boiler containing
same substantially as described.
2. In an apparatus constructed mainly as described and used for the purpose
claimed in Claim 1 the use of a coke fire simultaneously for heating purposes and
the utilization of the combustion gases substantially as described.
3. In an apparatus as described and claimed in the two previous claims the
utilization of combustion gases after washing and cooling of same for the purpose of
regenerating the mono carbonate alkali solution previous to its being brought to
the boiling vessel substantially as described.
4. The combination of two boiling vessels for the purpose of creating two
stages riza low pressure vessel for the first stage and a high pressure boiler for
the second stage the whole substantially as described.
5. The combination of an apparatus for the purpose of producing carbonic acid
of a high pressure boiler and an arrangement by which the combustion gases
obtained from the coke fire are being utilized in connection also of steam emanating
from the high pressure boiler for the respective purposes of regenerating the mono-
carbonate alkali solution, of keeping the concentration of the solution constant, of
utilizing the steam of the high pressure boiler for heating purposes, in connection
with the heating properties of the combustion gases and the means and devices, the
whole substantially as described.
Dated 1 L
Ր
1001
F. FANTA,
85, Gresham Street, Agent for Applicant.