Improved. Apparatus for Concentrating and Distilling Sulphuric Acid and other Liquids of High Boiling Point.
Year: 1894

page_text: Date of Application, 3rd Oct.,. 1894
Complete Specification Left, 3rd July, 1895-Accepted, 3rd Aug., 1895
PROVISIONAL SPECIFICAHON.
Improved. Apparatus for Concentrating and Distilling Sulphuric
Acid and other Liquids of High Boiling Point.
1, GEORG KRELL of Hüsten in Westphalia in the Empire of Germany,
Director, do hereby declare the nature of this invention to be as follows :—
The platinum boilers largely employed for completing the concentration of
sulphuric acid aro usually fired' by means of a simple grate furnace placed under-
neath. Recently, however, instead of a grate furnace, a generator furnace bas
been employed. In both cases the gases of combustion must have a very high
temperature in order to be capable of imparting the necessary amount of heat for
evaporation to the distilling vessel and to liquids of high boiling point, because the
transfer of heat from gaseous bodies-heating gases to metal takes place very
slowly.
The unavoidably great differences of temperature and the unequal distribution
of heat caused thereby on the walls of the vessel have a very deleterious action,
not only on the vessel itself, but also on the liquid which, is to be distilled which,
by coming in contact with the highly overheated metal surfaces, is more or less
injuriously altered or decomposed.
It is well known that the platinum vessels employed for concentrating sulphuric
acid are mainly attacked at those places where they are exposed to the most intense
heat. The slightest neglect in looking after the platinum vessels, or a very small
deposit of iron or lead salts, or mechanical impurities, on the bottom of the same
may at the very high temperature destroy the vessel in a very short time.
Sulphuric acid always undergoes during distillation a partial decomposition into
anhydride and water, which decomposition becomes greater the higher the degree
of heat employed for the distillation. All other bodies of high boiling point,
more particularly those of organic origin, always undergo more or less decomposition.
or carbonisation during the ordinary distillation in stills according to the degree.to
which the walls of the vessel are overheated:
The drawbacks herein before enumerated of the present method of treatment are
avoided by the apparatus which forms the object of this application.
A tube of platinum; gold, cast-iron, or even wrought iron lined with platinum or
gold, serves as distilling, that is to say, as evaporating vessel: The tube is placed
horizontally, and is closed at both ends to half its diameter by partitions made of
the same kind of metal as the vessel itself, so that the tube, when in action, always
remains half filled with sulphuric acid, or other suitable high boiling point' 'liquid*
which is to be treated.
Both ends of the tube are provided with an apparatus for condensing, cooling
and carrying off the evaporated products..
Warmed sulphuric acid or the like is continuously supplied at one end by means
of an inlet funnel. At the other end the undistilled part, that is to say, the
concentrated sulphuric acid, or the part of the liquid treated wbich is ‘of "high
boiling point is constantly carried away by means of a pipe:"
The evaporating tube is immersed in a suitable liquid, such as paraffin, a solution"
of salt, molten metal or the like, evenly heated to a suitably high degree, such¨

page_text: liquid being contained in a suitably heated vessel, the evaporating tube projecting
through the end walls of the same.
If the sulphuric acid, or the like, which is to he concentrated, be allowed to run
into the vessel, the apparatus delivers through the condensing apparatus placed at
the inlet end of the tube, a very weak distilled acid through the condensing apparatus
placed at the exit end of the tube a stronger distilled acid, and by the discharge
pipe acid concentrated to any desired degree according as more or less acid is allowed
to flow into the tube. When treating other liquids of high boiling point, the part
which boils the most easily is distilled off at the first condensing apparatus the
liquil of higher boiling point at the second, and the remainder of the liquid which
is concentrated, that is to say, of high boiling point, is discharged through the outlet
pipe.
Owing to all the surfaces of the distilling vessel being evenly heated, the
latter being entirely immersed in a suitably warmed liquid, which rapidly conveys
the necessary heat to the distilling vessel, it is possible to obtain the evaporation
with a minimum difference of temperature. By this means any overheating is
avoided, the distilling vessel is spared as much as possible, and the decomposition
of the sulphuric acid, or other liquid treated, is reduced to a minimum. Further,
by the rapid transfer of the heat of the bath of liquid to the metal of the distilling
vessel, it is possible to utilise the fuel employed for heating the apparatus to its
fullest extent.
The form of the tube (which for that matter may be of any suitable shape,
corrugated, sinuous or the like) is chosen because a tube can not only be turned
round, but also the rear end and the front end may be easily reversed and thus ant
even wearing away of the metal may be obtained."
Dated this 2nd day of October 1894.
WM. P. THOMPSON & Co.,
Of 6 Lord Street, Liverpool, Agents for the Applicant.
Improved Apparatus for Concentrating and Distilling Sulphurio
Acid and other Liquids of High Boiling Point.
I, GEORG KRELL of Hüsten in Westphalia in the Empire of Germany,
Director, 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 platinum boilers largely employed for completing the concentration of
sulphuric acid are usually fired by means of a simple grate furnace placed under-
Death. Recently, however, instead of a grate furnace, a generator furnace has
been employed. In both cases the gases of combustion must have a very high
temperature in order to be capable of imparting the necessary amount of heat
for evaporation to the distilling vessel and to liquids of high boiling point, because
the transfer of heat from gaseous bodies-heating gases-to metal takes place
very slowly.
The unavoidably great differences of temperature and the unequal distribution
of heat caused thereby on the walls of the vessel have a very deleterious action,
not only on the vessel itself, but also on the liquid which is to be distilled, which,
by coming in contact with the highly overheated metal surfaces, is more or less
injuriously altered or decomposed.
li is well known that the platinum vessels employed for concentrating sulphuric
acid are mainly attacked at those places where they are exposed to the most
intense heat. The slightest neglect in looking after the platinum vessels, or n
very small deposit of iron or lead salts, or mechanical impurities, on the bottoni

page_text: f the same may at the very high temperature destroy the vessel in a very short
ime.
Sulphuric acid always undergoes during distillation a partial decomposition into
uhydride and water, which decomposition becomes greater the higher the degree.
of heat employed for the distillation. All other bodies of high boiling point, more.
particularly those of organic origin, always undergo more or less decomposition or
arbonisation during the ordinary distillation in stills according to the degree to
which the walls of the vessel are overheated.
The drawbacks bereinbefore enumerated of the present method of treatment are
voided by the apparatus which forms the object of this application.
In the accompanying drawing
of the same may at the very high temperature destroy the vessel in a very short
time.
Sulphuric acid always undergoes during distillation a partial decomposition into
auhydride and water, which decomposition becomes greater the higher the degree.
of heat employed for the distillation. All other bodies of high boiling point, more
particularly those of organic origin, always undergo more or less decomposition or
carbonisation during the ordinary distillation in stills according to the degree to
which the walls of the vessel are overheated.
The drawbacks herein before enumerated of the present method of treatment are
voided by the apparatus which forms the object of this application.
In the accompanying drawing
Figure 1 shows a vertical longitudinal section of the apparatus ;
Figure 2 a vertical cross section ;
Figure 3 a plan view.
A tube A of platinum, gold, cast-iron, or even wrought iron lined with platinum
or gold, serves as distilling, that is to say, as evaporating vessel. The tube A is
placed horizontally, and is closed at both ends to half its diameter by partitions B
made of the same kind of metal as the vessel itself, so that the tube, when in action.
always remains half filled with sulphuric acid, or other suitable high boiling point
liquid which is to be treated.
Both ends of the tube are provided with an apparatus for condensing, cooling
and carrying off the evaporated products.
Warmed sulphuric acid or the like is continuously supplied at one end by means
of an inlet funnel C. At the other end the undistilled part, that is to say, the
concentrated sulphuric acid, or the part of the liquid treated which is of high
boiling point, is constantly carried away by means of a pipe D.
The evaporating tube A is immersed in a hot bath of molten lead contained in
a suitably heated vessel E, the evaporating tube projecting through the end walls
of the same.
If the sulphuric acid, or the like, which is to be concentrated, be allowed to run
into the vessel, the apparatus delivers, through the condensing apparatus placed at
the inlet end of the tube, a very weak distilled acid, through the condensing
apparatus placed at the exit end of the tube a stronger distilled acid, and by the
discharge pipe D acid concentrated to any desired degree according as more or less
acid' is allowed to flow into the tube. When treating other liquids of high boiling
point, the part which boils the most easily is distilled off at the first condensing
apparatus, the liquid of higher boiling point at the second, and the remainder of
the liquid which is concentrated, that is to say, of high boiling point, is discharged
through the outlet pipe D.
Owing to all the surfaces of the distilling vessel A being evenly heated, the
latter being entirely immersed in a suitably warmed bath, which rapidly conveys the.
necessary heat to the distilling vessel, it is possible to obtain the evaporation with
a minimum difference of temperature. By this means any overheating is avoided,
the distilling vessel is spared as much as possible, and the decomposition of the
sulphuric acid, or other liquid treated, is reduced to a minimum. Further, by the
rapid transfer of the heat of the contents of the bath to the metal of the distilling
vessel, it is possible to utilise the fuel employed for heating the apparatus to its
fullest extent.
The form of the tube (which for that matter may be of any suitable shape,
corrugated, sinuous or the like) is chosen because a tube can not only be turned
round, but also the rear end and the front end may be easily reversed and thus an
even wearing away of the metal may be obtained.
Having now particularly described and ascertained the nature of my said inveu-
tion and in what manner the same is to be performed, I declare that what
claim is :-
1. An apparatus for concentrating high grade sulphuric acid and the like by

page_text: distillation or evaporation characterised, by, the distilling or, evaporating vessel
being immersed in a bath of molten lead substantially as hereinbefore described
and shown in the accompanying drawing..
2. In an apparatus for concentrating, acids and the like such as described in
Claim 1, the tubular, form of construction of the distilling or evaporating vessel
substantially as herein before described and fer the object.set forth.
יח.
Dated this 2nd day of July 1895:
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
145