Improvements in Obtaining Chlorine.
Year: 1893

page_text: Date of Application, 20th June, 1893
Complete Specification Left, 26th July, 1893-Accepted, 2nd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Obtaining Chlorine.
We, ADOLPH VOGT, Chemical Engineer, and ANDREW ROSS SCOTT, Manu-
facturing Chemist. of Carntyne Chemical Works, Parkhead, in the County of
Lanark, North Britain, do hereby declare the nature of this invention to be as
follows, that is to say :-
Our said invention relates to the obtainment of chlorine from hydrochloric acid
by means of nitric and sulphuric acids and has for its object to simplify and improve
the process and to render it more economical and satisfactory than as hitherto
conducted.
Our invention consists in causing streams or currents of the three acids to flow
all in one direction through suitable apparatus whilst subjected to suitable heat.
In carrying out our invention we employ apparatus made of or lined with lead or
other not easily corrodible material, the apparatus consisting of a covered channel
which is horizontal or slightly inclined. Through the channel a continuous stream
of sulphuric acid is maintained, and above the sulphuric acid hydrochloric acid,
preferably gaseous is led into the apparatus at the same end at which the sulphuric
acid enters. Along with the other acids nitric acid is admitted in a manner to flow
along the surface of the sulphuric acid without mixing therewith to any great
extent. Or the nitric acid may be admitted in a vaporised condition.
perature of about 125 degrees, centigrade, is maintained at the entering end, and
along the channel the temperature may gradually decrease to about 105 degrees at
the other end.
A tem-
The channel may consist of a single straight length or of a number of lengths
connected at alternate ends to form a tortuous course; and the heat may be applied
by means of a furnace with flues extending under the channel or channels. Or
more or less of the heat may be due to the sulphuric acid being admitted in a
heated state, as for example when supplied directly from concentrating apparatus.
As the acids flow through the apparatus reactions take place resulting in the
production of free chlorine and gaseous nitrogen compounds which are led from
the channel into apparatus in which the nitrogen compounds are separated from
the chlorine by well known means.
The sulphuric acid becomes diluted with water taken up by it in the reactions
but leaves the apparatus practically free from nitrogen compounds, and merely
requires concentration to enable it to be used over again.
Nitric acid is, by well known means, reformed from the gaseous nitrogen com-
pounds, some hydrochloric acid being also reformed from chlorine forming a
constituent of those compounds.
Dated this Nineteenth day of June 1893.
EDMUND HUNT,
Applicants' Agent.
COMPLETE SPECIFICATION.
Improvements in Obtaining Chlorine.
We, ADOLPH VOGT, Chemical Engineer, and ANDREW Ross SCOTT, Manu-
facturing Chemist, of Carntyne Chemical Works, Parkhead, in the County of
Lanark, North Britain, 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, that is to say :-
This invention relates to the obtainment of chlorine from hydrochloric acid by

page_text: means of nitric and sulphuric acids, and has for its object to simplify and improve
the process, and to render it more economical and satisfactory than as hitherto
conducted.
The invention consists in causing streams or currents of the three acids to flow
in a continuous manner all in one direction through suitable apparatus, whilst
subjected to suitable heat.
In carrying out the invention the apparatus employed is made of or lined with
lead or other not easily corrodible material, and consists of a covered channel which
is horizontal or slightly inclined. Through the channel a continuous stream of
sulphuric acid is maintained, and above the sulphuric acid hydrochloric acid,
preferably gaseous, is led into the apparatus. Along with the other acids, nitric
acid is admitted in a manner to flow along the surface of the sulphuric acid without
mixing therewith to any great extent. Or the nitric acid may be admitted in a
vaporised condition. ▲ temperature of 125 degrees centigrade is maintained
throughout the apparatus; or the temperature may gradually decrease along the
channel to a terminal temperature of 105 degrees.
The channel may consist of a single straight length, or of a number of lengths
connected at alternate ends to form a tortuous course; and the heat may be applied
by means of a furnace with flues extending under the channel or channels. Or
more or less of the heat may be due to the sulphuric acid being admitted in a
heated state, as-for example, when supplied directly from concentrating apparatus.
As the acids flow through the apparatus, reactions take place resulting in the
production of free chlorine and gaseous nitrogen compounds, which are led from
the channel into apparatus in which the nitrogen compounds and any hydrochloric
acid are separated from the chlorine by well known means.
The sulphuric acid becomes diluted with water taken up by it in the reactions,
but leaves the apparatus practically free from nitrogen compounds, and merely
requires concentration to enable it to be used over again.
Nitric acid is by well known means reformed from the gaseous nitrogen com-
pounds, some hydrochloric acid being also reformed from chlorine forming a
constituent of those compounds.
And in order that the said invention and the manner of performing the same
may be properly understood there is hereunto appended a sheet of explanatory
drawings to he hereinafter referred to and representing by way of example a form
of apparatus suitable for carrying out the invention.
In
Figure, 1, of the drawings, is a diagrammatic plan, and Figure, 2, is a corre-
sponding sectional elevation, whilst Figure, 3, is an enlarged vertical section as
taken along a part of the channel and transversely to Figures, 1, and 2.
these drawings the same reference numerals and letters are used to mark the same
or like parts wherever they are repeated.
At the left-hand parts of Figures, 1, and, 2, à furnace, 4, is shown, arranged for
heating a set of pans, 5, for reconcentrating the sulphuric acid which becomes
diluted in the process. From the pans, 5, the concentrated sulphuric acid is trans-
ferred by means of a siphon, a, to a reservoir or tank, 6, from which it is supplied
by means of a siphon, 7, to the channel apparatus in which the process constituting
the invention is in operation. This channel apparatus consists of a rectangular
lead or lead-lined structure, 8, divided into four transverse lengths by vertical
partitions, 9, of which one is shown separately in Figure, 3, and the spaces thereby
formed are subdivided by partitions, 10, none of which reach the bottom but which
are formed and placed in a manner to allow gases to flow alternately under and
over each in succession. The partitions, 9, are made each with lower and upper
openings, 11, 12, at one end, the lower opening being for the passage of the liquids
and the upper one for the gases; and these openings, 11, 12, are at opposite ends
of the alternate partitions, 9, the dotted lines in Figure, 3, indicating the positions
of the openings in the next partition. With these arrangements the liquids and
'gases flow from the inlet part, 13, along the spaces formed by the partitions, 9,
alternately in opposite directions to the outlet part, 14, the partitions, 10, at right

page_text: angles to the partitions, 9, being for the purpose of keeping the gases well mixed
and of preventing portions passing along the tops of the spaces without approaching
the liquids.
The sulphuric acid is caused to flow through the apparatus in a stream having a
small depth of, for example, 2 to 4 centimetres. The nitric acid is supplied from
a reservoir or tank, 15, by a pipe, b, and inlet trap, c, which prevents escape of gas,
and is introduced at the inlet part, 13, at the surface of the sulphuric acid so that
it may flow along that surface with as little mixing as possible. The hydrochloric
acid is supplied at the inlet part, 13, by a pipe, 16. The gaseous chlorine and
nitrogen compounds formed in the process by the reactions between the three acids,
leave the channel apparatus, 8, at the outlet part, 14, by a pipe, 17, communicating
with the bottom of a tower, 18, up which the gases pass whilst sulphuric acid passes
downwards to absorb the nitrogen compounds. From the top of the tower, 18, the
chlorine having mixed with it some hydrochloric acid passes by a pipe, 19, to the
bottom of a second tower, 20, down which water is passed to absorb the hydro-
chloric acid. Finally the chlorine is led by a pipe, 21, to the bottom of a third
tower, 22, in which it is acted on by sulphuric acid to absorb moisture; and it may
then be passed to lime chambers or used in any desired manner
When the sulphuric acid leaves the channel apparatus, 8, at the outlet part, 14,
it is still strong enough for dehydrating hydrochloric acid as that acid comes from
the ordinary salt-decomposing furnace, and it is used for that purpose in supple-
mentary channel apparatus, 23, which is internally divided like the main chaunel
apparatus, 8, the fresh hydrochloric acid gas entering by a pipe, d, at the part, 24,
at which the sulphuric acid finally leaves the apparatus and leaving it at, 25, at
which the sulphuric acid enters from the other apparatus, 8. The dried hydro-
chloric acid leaves the channel apparatus, 23, by a pipe, 26, and is by preference
passed through any suitable measuring apparatus before being supplied by the
pipe, 16, to the main channel apparatus, 8, in order that the quantities of nitric
acid and sulphuric acid introduced may be suitably proportioned to the hydrochloric
acid.
a
The hydrochloric acid may be introduced in an aqueous condition, in which case
the quantity of sulphuric acid must be proportionately increased to absorb the
larger quantity of water.
The diluted sulphuric acid is by means of a pump, 27, and pipes, 28, transferred
to the concentrating pans, 5.
The channel apparatus, 8, and, 23, is heated by means of a furnace, 29, from
which flues, 30, extend under the apparatus.
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 :-
The improved continuous process for obtaining chlorine, in which process hydro-
chloric acid, preferably dry, is made to flow through channel apparatus over and
in the same direction with a stream of sulphuric acid with which there also flows
nitric acid, the said process being capable of modification by using aqueous
hydrochloric acid with an increased proportion of sulphuric acid, or by intro-
ducing the nitric acid in a vaporised condition, all substantially as hereinbefore
described.
Dated this fifth of T.1 1002
EDMUND HUNT,
Applicants' Agent.