Improvements in the Manufacture of Chlorine from Hydrochloric Acid Gas.
Year: 1895

page_text: Date of Application, 12th July, 1895
Complete Specification Left, 11th Apr., 1896-Accepted, 13th June, 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Chlorine from Hydrochloric
Acid Gas.
We, THOMAS THOMPSON BEST Ph. D. Analytical Chemist, ANDREW KAY,
Works Manager and JOHN BROCK, Director of The United Alkali Company
Limited all of G11 Exchange Buildings Liverpool in the County of Lancaster, do
hereby declare the nature of this invention to be as follows :—
Chlorine is now largely manufactured by subjecting 'at an elevated temperature
a mixture of hydrochloric acid gas and air to the action of contact or catalytic
substances, such as platinised asbestos, or porous materials such as pumice stone, or
broken bricks impregnated with salts, such as salts of copper in the Deacon process,
or manganese and magnesia in other processes.
.
In all these processes only a certain portion of the hydrochloric acid is
decomposed to form chlorine a comparatively large amount of hydrochloric acid
escaping undecomposed.
"
Attempts have been made to remedy this defect by causing the mixture of gases
to pass through considerable lengths of contact material, and by previously drying
the gases. Notwithstanding these improvements the amount of hydrochloric acid
left undecomposed in the gases is still considerable, and entails considerable expenses.
in its recovery.
.:
This invention has for its object to reduce to a minimum this loss of hydrochloric
acid. If a dry gaseous mixture of hydrochloric acid, and air be passed over or
through a contact substance at a suitable temperature, for instance through one of
"Deacon's decomposers," in the usual manner, the gaseous mixture leaving this
decomposer contains beside the residue of atmospheric air, chlorine, hydrochloric
acid gas, and steam. The latter is one of the products of the decomposition of the
bydrochloric acid gas by the atmospheric oxygen according to the equation
1
According to this invention the water thus formed by the decomposition of the
hydrochlorate acid.. is. removed, and then the remaining hydrochloric acid is
decomposed to a great extent, if not wholly, by passing the gas a second time
through such a decomposer.
This invention may be carried out by causing the gases which issue from
a Deacon, or other similar decomposer to cool and then to come into contact with a
bygroscopic substance such as sulphuric acid, which absorbs the water from the
gaseous mixture. The dry gas we then pass again through a Deacon decomposer;
or through other apparatus filled with a suitable catalytic substance and by this
most of the hydrochloric acid which escaped decomposition during the first passage
of the gas through the decomposer will be decomposed and chlorine liberated.,
This process may be repeated any number of times, desired..
Dated this 12th day of July 1895.
I

page_text: Improvements in the Manufacture of Chlorine from Hydrochloric
Acid Gas.
We THOMAS THOMPSON BEST Ph. D. Analytical Chemist ANDREW KAY
(late Works Manager) and JOHN BROCK, Director of The United Alkali Company
Limited all of G 11 Exchange Buildings Liverpool in the County of Lancaster
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 :-
Chlorine is now largely manufactured by subjecting at an elevated temperature
a mixture of hydrochloric acid gas and air to the action of contact, or catalytic,
substances, such as platinised asbestos, or porous materials, such as pumice stone, or
broken bricks, impregnated with salts, such as salts of copper in the Deacon
process, or manganese and magnesia in other processes.
In all these processes, only a certain portion of the hydrochloric acid is
decomposed to form chlorine, a comparatively large amount of hydrochloric acid
escaping undecomposed.
Attempts have been made to remedy this defect by causing the mixture of
gases to pass through considerable lengths of contact material, and by previously
drying the gases.
:
Notwithstanding these improvements the amount of hydrochloric acid left
undecomposed in the gases is still considerable, and entails considerable expense in
its recovery.
This invention has for its object to reduce to a minimum this loss of hydrochloric
acid. If a dry gaseous mixture of hydrochloric acid and air be passed over,
or through, a contact substance at a suitable temperature, for instance through one
of "Deacons decomposers," in the usual manner, the gaseous mixture leaving this
decomposer contains, besides the residue of atmospheric air, chlorine, hydrochloric
acid gas, and steam. The latter is one of the products of the decomposition of the
hydrochloric acid gas by the atmospheric oxygen, according to the equation :—
:
"
According to this invention the water thus formed by the decomposition of the
hydrochloric acid is removed, and then the remaining hydrochloric acid. is
decomposed to a great extent, if not wholly, by passing the gases a second time
through such a decomposer. The gases which issue from a "Deacon or other
similar decomposer are caused to cool and then to come into contact with a
hygroscopic substance such as sulphuric acid, which absorbs the water from the
gaseous mixture. The dried gases are then passed again through a "Deacon "
decomposer or through other apparatus filled with a suitable catalytic substance,
and by this most of the hydrochloric acid which escaped decomposition during the
first passage of the gas through the decomposer will be decomposed and chlorine
liberated. This process may be repeated any number of times, if desired.
"
The said invention may be carried out by causing the gaseous mixture consisting
of chlorine, hydrochloric acid gas, water-vapour, and air, which issues from an
ordinary "Deacon or other similar, decomposer to pass in an upward direction,
through a tower, or series of towers, containing coke or other material presenting a
large surface, the gaseous mixture therein meeting concentrated sulphuric acid
passing downwards over the coke or like material. The gases on coming in contact
with the sulphuric acid are deprived of the vapour of water and are then passed
through a second decomposer, when a further portion of the hydrochloric acid is
3. .'

page_text: decomposed, and a further amount of vapour of water is produced, which may
again be removed in a second drying tower, or series of towers, and the gases may
be passed a third time through a decomposer and so on, if desired, until the whole,.
or nearly the whole, of the hydrochloric acid is decomposed.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we-
claim is :-
In the manufacture of chlorine from hydrochloric acid gas by what are known as.
catalytic processes, removing from the partially decomposed gaseous mixture of
hydrochloric acid gas, chlorine, air, and steam which passes from a "Deacon "
decomposer or equivalent apparatus, the vapour of water by means of hygroscopic
substance, so as to enable the remaining hydrochloric acid gas to be again acted
upon by the oxygen of the air in presence of the catalytic agent substantially as.
hereinbefore described.
Dated this 11th day of April 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents..