Improvements in the Manufacture of Chlorine from Hydrochloric Acid Gas.
Year: 1891

page_text: Date of Application (in United Kingdom), 21st Dec., 1891
Complete Specification Left. 21st Dec.. 1891-Accented 30'h Jan
1812
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Chlorine from Hydrochloric
Acid Gas.
We LA SOCIETE A. R. PECHINEY & CIE., of Salindres (Gard) in the Republic
of France 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 those processes for the manufacture of
chlorine which are based upon the decomposition of hydrochloric acid gas by oxygen
for the purpose of separating the chlorine from the former.
This decomposition is effected sometimes by causing a mixture of hydrochloric
acid gas and oxygen or of hydrochloric acid gas and air to pass over certain solid
substances which accelerate or promote the decomposing action and sometimes by
causing hydrochloric acid gas and oxygen or air to pass alternately or in succession
over certain other solid substances.
The well known Deacon process is typical of the first category as is also the
De Wilde and Reychler process inasmuch as it is worked in a continuous manner
with the aid of a mixture of hydrochloric acid gas and air.
To the second category belongs the process attributed to the same inventors
Messrs. De Wilde and Reychler when it is worked not with the mixture of
hydrochloric acid gas and air but with these two gases employed separately and in
succession.
In all these processes the hydrochloric acid gas and the air are caused to pass
either mixed or separately according to circumstances through tubular apparatus of
cast iron heated externally. From this apparatus these gases pass directly into the
decomposer and that is the means by which the greater part of the caloric which is
required for the decomposition of the hydrochloric acid gas becomes carried into
the said decomposing apparatus.
The improvement forming the object of the present invention consists in heating
the hydrochloric acid gas and the air or oxygen in apparatus such as that employed
in metallurgical operations for heating the air supplied to blast furnaces and
known as the hot blast stoves of Cowper-Siemens, Whitwell and others, in place
of heating them in the customary tubular apparatus of cast iron hereinbefore
referred to.
The following advantages result from this substitution namely:
:-
1. The working is facilitated and requires less watching there being no danger of
over-heating or burning the heating apparatus.
2. The gases to be heated, hydrochloric acid gas and air, whether employed
mixed or separately do not affect the refractory materials with which the beating
apparatus is lined and consequently the expense of wear and tear of the latter is
almost mil.
3. This method of heating enables the gases to be heated to higher temperatures
than is possible with the cast iron tubular apparatus so that it becomes possible to

page_text: employ as the solid acting substance materials with which the reaction does not
take place properly except at a higher temperature than is possible with the cast
iron apparatus, but which present, compared to other materials, the advantages of
being cheaper and of retaining their activity for a longer period of time. Magnesia
(preferably in the form of bricks entire or broken) and De Wilde and Reychler's
mixture (sulphate of magnesia & oxides of manganese and of magnesium) are
examples of substances which may thus be employed.
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 :-
:-
:
and
In the manufacture of chlorine, heating the mixture of hydrochloric acid gas
air (or oxygen) or either of them separately by means of Cowper-Siemens,
Whitwell and other similar hot blast stoves substantially as hereinbefore
described.
Dated this
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.