Improvements in the Manufacture of Sulphuric Anhydride and Apparatus for Use therein.
Year: 1898

page_text: Improvements in the Manufacture of Sulphuric Anhydride and
Apparatus for Use therein.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by the Badische Anilin & Soda Fabrik, of
Ludwigshafen-on-Rhine, in the German Empire) to be as follows:-
In the chamber-process for the manufacture of sulphuric acid, the gases under
treatment are largely, or entirely, kept in motion in the desired direction by the
very economical means of the draught of a high chimney. If it be desired to
prepare the acid of the strength of ordinary unconcentrated chamber acid by
means of the contact process, a similar regard for economy in details must be
observed and everything avoided causing additional expense.
If, in this process, platinised abestos, or a similar loose contact mass, be used,
and merely packed into plain tubes, then on forcing through the mixed gases,
the contact mass is so pressed together as to require considerable pumping
pressure to force the gases through the mass. Further it has been held that under
pressure the gases combine more efficiently and patents have been granted for
operating in this way. My foreign correspondents have found that the advantage,
if any, of working under pressure is more than counter-balanced by the cost of
producing the pressure. The process is therefore preferably conducted at about
atmospheric pressure and my foreign correspondents have devised means whereby
the pressure to be overcome in contact-tubes, and consequently the cost of pump-
ing, or forcing, the mixed gases through the contact mass, is reduced to a
minimum.
For this purpose the tubes containing the contact-mass are divided into a
number of compartments, by the insertion of a number of perforated plates, or
sieves, and upon each plate, or sieve, sufficient contact-mass only, is placed to
cover the perforations or reticulations and the periphery of the plates at the wall
of the tube. The principle is that the pressure on one layer of the contact mass
shall not be transmitted to the next layer so that the layers can be pressed together
and further the arrangement must be such that the gases cannot pass any plate
except through the contact-mass. Thus an iron-rod may be fixed at the bottom
of the contact-tube passing up its central line, over this a narrow tube may be
placed extending up the rod to the height in the interior of the contact-tube,
where the contact-mass begins. The first perforated or reticulated plate is then
passed down the contact-tube, over the rod, and is held in position by the narrow
tube. Upon this sufficient contact-mass is placed to cover the perforations or
reticulations and periphery as aforesaid. Upon this is placed a bead or short
piece of tube, and upon that the next perforated or reticulated plate and so on..
The length of the bead or piece of tube regulates the distance apart of the layers
of the contact mass which can thus be varied at will. In this way the contact

page_text: mass presses against the plates, and this pressure is transferred to the beads and
tube, so that the contact mass as a whole is greatly relieved of pressure and a
more satisfactory result achieved.
Of course other means can be adopted provided that the principles above stated
be observed, for example the plates or sieves can be supported by tripods instead
of by the central rod and tubes, or beads,
Improvements in the Manufacture of Sulphuric Anhydride and
Apparatus for Use therein.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by the Badische Anilin & Soda Fabrik, of
Ludwigshafen-on-Rhine, in the German Empire) and in what manner the same is
to be performed. to be particularly described and ascertained in and by the follow-
ing statement:-
In the chamber process for the manufacture of sulphuric acid. the gases under
treatment are largely, or entirely, kept in motion in the desired direction by the
very economical means of the draught of a high chimney. If it be desired to
prepare the acid of the strength of ordinary unconcentrated chamber acid, by
means of the contact-process a similar regard for economy in details must be
observed and everything avoided causing additional expense.
It, in this process, platinized asbestos (see the Specification of Winckler's
German Patent 4566; Lunge; "Sulphuric acid and alkali" 2nd Edit. Vol 1
page 863, and Dammer Chemische Technologie Vol. 1, page 189) be used, and
merely packed into plain tubes, then, on forcing the mixed gases through the
contact-mass it is so pressed together as to require considerable pumping pressure
to force the gases through the mass. Further it has been held that under pressure
the gases combine more efficiently and patents have been granted for operating
in this way.
My foreign correspondents have found that the advantage, if any,
of working under pressure is more than counterbalanced by the cost of producing
the pressure. The
process is therefore preferably conducted at about atmospheric
pressure and my foreign correspondents have devised means whereby the pressure
to be overcome in contact-tubes, and consequently the cost of pumping, or forcing,
the mixed gases through the contact-mass, is reduced to a minimum.
For this purpose and referring to the accompanying drawings, the tubes R
containing the contact mass are divided into a number of compartments, by the
insertion of a number of perforated plates, or sieves (shewn in plan above each
figure) and upon cach plate, or sieve only sufficient contact mass is placed to
cover the perforations, or reticulations, and the periphery of the plates at the
wall of the tube. The principle is that the pressure on one layer of the contact-
mass shall not be transmitted to the next layer so as to press the layer together;
and further, the arrangement must be such that the gases cannot pass any plate
or sieve except through the contact-mass. Thus an iron rod a may be fixed in
the part D at the bottom of the contact-tube R, passing up its axis and over
this rod a a short tube 6 may be placed at the bottom of the rod and extending
up it to where the contact-mass begins in the interior of the contact-tube. The

page_text: first perforated, or reticulated plate, or sieve e is then passed, down the contact
tube, over the rod a and is held in position by resting on the narrow tube 6. Upon
this sufficient contact-mass is placed to cover the perforations, or reticulations,
and periphery as aforesaid. Upon this is placed a bead, or short piece of tube d
and upon this the next perforated or reticulated, plate or seive c¹ and so on with
the tubes d' d and plates c¹ c c and those following. The length of the beads
or pieces of tube d regulates the distance apart of the layers of the contact-mass
which can thus be varied at will. In this way the contact-mass presses against
the plates or sieves, and this pressure is transferred to the beads and tube so
that the contact-mass as a whole is greatly relieved of pressure and a more
satisfactory result is achieved.
This arrangement of the layers of contact-substance has the further advantage
in that the gas, after passing each layer, has an opportunity of mixing again, so
that the temperature of the gas, passing through the different parts of the layer
of contact-mass becomes equalized by the mixing, and the cooling effect described
in Specification of my Application for Letters Patent No. 15949 of even date
herewith, is rendered more effective.
Of course other means can be adopted instead of those given in the above
example, provided that the principle above stated be observed. For example
the plates, or sieves, can be supported by tripods (d d¹ d) as shewn in Figure 2
instead of by the central-rod and tubes or pipes as in Figure 1.
It is essential that the methods adopted for preventing packing of the contact-
substance and consequent increase in the pressure required for forcing the gas
through the apparatus must not be such as to prevent the regulated cooling
herein before referred to, which is essential to the success of the process...
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I claim is :-
1. The improvement in the manufacture of sulphuric anhydride by the contact-
process consisting in so constructing the apparatus that it can be worked at
pressures differing but little from atmospheric pressure the same being attained
by arrangement of the contact-mass so that it is capable of being effectively
cooled, and the layers of which it consists are supported so that they cannot press
upon one another and no other path is open to the gases except through the
contact-mass.
2. For use in the manufacture of sulphuric anhydride a vessel for containing
the contact-mass such vessel having supported, at intervals in its interior, per-
forated, or reticulated, trays, or plates, which support layers of the contact-mass
the gas passing through the contact-mass at approximately atmospheric pressure,
substantially as, and for the purposes hereinbefore described with reference to the
accompanying drawings.