Improvements in or relating to the Recovery of Nitrous Gases in the Manufacture of Sulphuric Acid.
Year: 1898

page_text: Date of Application, 20th Sept., 1898
Complete Specification Left, 5th June, 1899-Accepted, 15th July, 1899
Improvements in or relating to the Recovery of Nitrous Gases in the
Manufacture of Sulphuric Acid.
A communication from ANTOINE FRANCOIS IZIDORE and MARIUS BISCONS, Chemists,
of Allée des Vitarelles, Toulouse, Haute Garonne, France.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention to be
as follows:
-
This invention relates to a device enabling the nitrous gases or fumes in the
manufacture of sulphuric acid to be completely recovered on their escape from
the lead chambers or Gay Lussac towers.
A portion of the oxides of nitrogen in the chambers acts directly on the
sulphurous acid and oxidises it, another portion permanently remains in the atmo-
sphere of the chambers, a third is found in solution in the liquid in the saucer,
and finally the last portion which hitherto could not be collected completely and
which is not the smallest, escapes through the chimneys of the chambers the
result being that the air, in presence of the reactions which take place, power-
fully contributes to the reconstitution or to the production of nitrous compounds.
All these compounds are utilised in the manufacture of sulphuric acid,
except the dioxide of nitrogen which passes through the Gay Lussac tower with
out being arrested and on escaping from the chimney is transformed, in pre-
sence of air, into vapours of hyponitric acid which are lost.
If these vapours could be collected, they could be utilised like the preceding
ones and would succeed in replacing about 3 to 4% of nitrate for 100 kilogrammes
of burnt sulphur which is at present required in the manufacturing of sulphuric
acid even in the best apparatus, so that their total recovery would render the
expenditure of nitric acid nearly nought.
On the other hand by introducing into the furnaces a sufficient quantity of
air to try to transform the final dioxide of nitrogen into nitrous or hyponitric
acids, too great a quantity of this substance would be obtained in the chambers,
which would hamper the reactions and cause a perceptible waste of sulphurous
acid through the chimney.
It is therefore absolutely necessary always to regulate the admission of air
in proportion to the quantity of sulphur used. Consequently if it is desired not
to lose dioxide of nitrogen, an attempt to recover it must be made only at its
escape from the chambers.
This is the object of the apparatus according to this invention, destined to
replace Gay Lussac tower in new works or to be combined with said towers in
existing works.
A convenient form of apparatus for carrying out this invention, which may
be either secured to the walls of the lead chambers or arranged independently
of the latter, comprises a lead conduit of cylindrical or prismatic shape arranged
at a suitable angle and provided with barriers or stops arranged at intervals
on the bottom of said conduit and enabling said bottom to be covered by a layer
of sulphuric acid at 60° constantly circulating in cascades from barrier to barrier,

page_text: in the opposite direction to that of the gases coming from the chamber which are
kept in continuous contact with the acid and to which gases the conduit offers
a perfectly free passage throughout the whole of its length.
In the vertical portions forming the bends there are arranged obstacles or
baffle plates for the purpose of ensuring this contact between the gases and the
acid.
Near the orifice for the admission of gases a nozzle of a blower enters the con-
duit in order to supply a slight current of air in the direction of the movement
of the gases.
A reservoir is provided for the supply of sulphuric acid at 60° and a second
reservoir for the collection of the nitrous sulphuric acid. The apparatus is also
furnished with an outlet for the escape of the gases after treatment.
As the apparatus works in exactly the same manner as a Gay Lussac tower
the dioxide of nitrogen contained in the gases being oxidised in the presence of
the air introduced and converted into nitrous and hyponitric acids, which go to
increase the amount of similar products coming from the chambers and which
the sulphuric acid circulating in the opposite direction has for its function to
reduce.
All nitrous products whatever they be are thus arrested and become utilisable
for the oxidation of sulphurous acid at the entrance of the chambers.
This apparatus has the great advantage over the Gay Lussac tower of never
obstructing the draught which is a very important point, the draught can indeed
be regulated as desired by the blower.
Finally complete absorption of fumes which have hitherto escaped into the
atmosphere is a great advantage in view of the injurious action of the sulphuric
acid works on the health of the surrounding locality.
The total volume of the conduit must be at least equal to that of a Gay Lussac
tower, that is to say from 1 to 1% of the total volume of the chambers. The
length must be made as great as possible and the cross sectional area about two-
thirds that of the conduits supplying the gas from the furnaces into the chambers.
The apparatus may be modified so as to be economically employed in existing
works without reconstructing them.
In this case a vertical conduit is arranged by the side of the tower from which
nitrous gases escape a tube conducting them from the top of the tower to the
bottom of the conduit. The nozzle of the blower is preferably connected to
this tube. The conduit is furnished with battle plates arranged on its sides over
which flows sulphuric acid coming from an overhead reservoir. The gases cireu-
late in the column in an upward direction and are mixed with the current of
air introduced by the blower.
Nitrous sulphuric acid is collected at the botton and the exhausted gases
escape at the top of the conduit.
Dated this 19th day of September 1898.
DATTT 1
TI ATS
Agents for the Applicant.
Improvements in or relating to the Recovery of Nitrous Gases in the
Manufacture of Sulphuric Acid.
A communication from ANTOINE FRANÇOIS IZIDORE, and MARIUS BISCONS, Chemists,
of Allée des Vitarelles, Toulouse, Haute Garonne, France.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention and in

page_text: what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to a device enabling the nitrous gases or fumes in the
manufacture of sulphuric acid to be completely recovered on their escape from
the lead chambers or Gay Lussac towers.
A portion of the oxides of nitrogen in the chambers acts directly on the sulphu-
rous acids and oxidises it, another portion permanently remains in the atmo-
sphere of the chambers, a third is found in solution in the liquid in the saucer,
and finally the last portion which hitherto could not be collected completely and
which is not the smallest, escapes through the chimneys of the chambers., the
result being that the air, in presence of the reactions which take place, power-
fully contributes to the reconstitution or to the production of nitrous compounds.
All these compounds are utilised in the manufacture of sulphuric acid,
except the dioxide of nitrogen which passes through the Gay Lussac tower with-
out being arrested and on escaping from the chimney is transformed, in pre-
sence of air, into vapours of hyponitric acid which are lost.
If these vapours could be collected, they could be utilised like the preceding
ones and would succeed in replacing about 3 to 4% of nitrate for 100 kilogrammes
of burnt sulphur which is at present required in the manufacturing of sulphuric
acid even in the best apparatus, so that their total recovery would render the
expenditure of nitric acid nearly nought.
On the other hand by introducing into the furnaces a sufficient quantity of
air to try to transform the final dioxide of nitrogen into nitrous or hyponitric
acids, too great a quantity of this substance would be obtained in the chambers,
which would hamper the reactions and cause a perceptible waste of sulphurous
acid through the chimney.
It is therefore absolutely necessary always to regulate the admission of air
in proportion to the quantity of sulphur used. Consequently if it is desired not
to lose dioxide of nitrogen, an attempt to recover it must be made only at its
escape from the chambers.
This is the object of the apparatus according to this invention, destined to
replace Gay Lussac towers in new works or to be combined with said towers in
existing works.
A convenient form of apparatus for carrying out this invention is illustrated,
by way of example in Figure 1 of the accompanying drawings, which shows in
vertical section of a device which may either be secured to the walls of the lead
chambers or arranged independently of the latter.
Figure 2 is a sectional view of a modified form of apparatus which may be
economically employed in existing works without reconstructing them.
Referring first to Figure 1, the apparatus comprises a lead conduit C of cylin
drical or prismatic shape arranged at a suitable angle and provided with barriers
or stops a, arranged at intervals on the bottom of said conduit and enabling said
bottom to be covered by a layer of sulphuric acid at 60° Bé. constantly circu-
lating in cascades from barrier to barrier, in the opposite direction to that of
the gases coming from the chamber, which enter at O and are kept in continuous
contact with the acid, and to which gases the conduit offers a perfectly free
passage throughout the whole of its length.
In the vertical portions forming the bends there are arranged obstacles or
baffle plates B B¹ B³ for the purpose of ensuring this contact between the gases
and the acid.
Near the orifice O for the admission of gases a nozzle V of a blower enters
the conduits in order to supply a slight current of air in the direction of the
movement of the gases.
A reservoir E is provided for the supply of sulphuric acid at 60° Bé. and a
second reservoir E for the collection of the nitrous sulphuric acid.
The
apparatus is also furnished with an outlet D for the escape of the waste gases.

page_text: As the apparatus works in exactly the same manner as a Gay Lussac tower
the dioxide of nitrogen contained in the gases being oxidised in the presence of
the air introduced and converted into nitrous and hyponitric acids, which go to
increase the amount of similar products coming from the chambers and which
the sulphuric acid circulating in the opposite direction has for its function to
reduce.
All nitrous products whatever they be are thus arrested and become utilisable
for the oxidation of sulphurous acid at the entrance of the chambers.
This apparatus has the great advantage over the Gay Lussac tower of never
obstructing the draught which is a very important point, the draught can indeed
be regulated as desired by the blower.
Finally complete absorption of fumes which have hitherto escaped into the
atmosphere is a great advantage in view of the injurious action of the sulphuric
acid works on the health of the surrounding locality.
The total volume of the conduit C must be at least equal to that of a Gay Lussac
tower, that is to say from 1 to 1% of the total volume of the chambers. The
length must be made as great as possible and the cross sectional area about two-
thirds that of the conduits supplying the gas from the furnaces into the chambers.
Referring now to Figure 2 which shows a form of apparatus modified so as to
be economically employed in existing works. without reconstructing them.
In this case a vertical conduit I is arranged by the side of the tower G from
which nitrous gases escape, a tube H conducting them from the top of the
tower G to the bottom of the conduit I. The nozzle V₁ of a blower is connected
to this tube. The conduit I is furnished with baffle plates i arranged on its
sides over which flows sulphuric acid at 60° Bé. coming from an overhead reser-
voir J. The gases circulate in the column in an upward direction and are mixed
with the current of air introduced by the blower.
Nitrous sulphuric acid is collected at L and the exhausted gases escape at K
from the top of the conduit.
Having now particularly described and ascertained the nature of the said in-
vention as communicated to me by my foreign correspondents and in what
manner the same is to be performed I declare that what I claim is:-
1. In the manufacture of sulphuric acid apparatus for the complete recovery
of nitrous fumes comprising a conduit provided with baffle plates into and
through which conduit the fumes from the lead chambers pass whilst a stream of
sulphuric acid and a current of air are caused to flow through the said conduit
in opposite directions substantially as described.
2. In the manufacture of sulphuric acid the use of air currents in denitrating
columns or towers for the complete recovery of nitrous gases and dioxide of
nitrogen substantially as described.
3. The complete apparatus for the recovery of nitrous gases or fumes substan-
tially as described or illustrated in Figure 1 or in Figure 2 of the accompanying
drawings.
Dated this 5th dove of Tun 1000
BOULT & WADE,
Agents for the Applicant.