Improvements in and connected with, and Apparatus for, the. Manu- facture or Production of Hydrogen Gas.
Year: 1897

page_text: Date of Application, 29th June, 1897-Accepted, 31st July, 1897
Improvements in and connected with, and Apparatus for, the. Manu-
facture or Production of Hydrogen Gas.
'
We, LEOPOLDO VITTORIA PRATIS, and PIETRO MARENGO, both of 33 Via Principe
Tommaso, Turin, in the Kingdom of Italy, Manufacturers, 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 the industrial production of hydrogen gas, use for any
to which such gas may be applied. We intend to employ it in place of coal gas
as an agent for raising refractory bodies or mantles to incandescence, for illumina-
tion, and as a heating agent for cooking and similar purposes, and in admixture
with air as an explosive agent for generating motive power in suitable engines;
and our invention provides means to enable it to be tlius employed, but whilst our
said invention is specially intended for such uses of the hydrogen gas produced
in accordance with our present invention, we do not restrict ourselves to such uses.
It has long been known that iron is capable of reacting with sulphuric acid, with
the formation of sulphate of iron and the elimination of hydrogen gas; and pro-
cesses have been proposed for utilizing this reaction. Heretofore, however, such
processes have been practically unavailable, and have, so far as we are aware, been
employed (when used at all) only occasionally and for limited times, more in the
way of experiment than in an industrial manner. Among the objections attending
such old processes, or certain of them, may be mentioned the slow generation of the
liydrogen, the obtainment of the sulphate of iron in very dilute solution from which
the sulphate of iron cannot economically be separated, and the crystallization of the
ferrous sulphate among the particles of iron in the generator, so as thereby
form a hard mass which can with difficulty be removed.:
14x
By our present invention the reaction of iron on sulphuric acid is utilized, whilst
at the same time the difficulties above mentioned are avoided. In accordance
with our said invention the iron in small particles is placed in a suitable generator
and the sulphuric acid admitted upon the iron in such proportion, and in such
dilution, as to form (as the result of the reaction) a pasty mass of iron, ferrous
sulphate and water, it having been discovered by us that in these proportions there
is a rapid generation of hydrogen with a practically complete saturation of the
sulphuric acid and with the formation of a residue which can be emptied by
dumping (say by simply dropping the bottoni of the generator), and which can be
economically utilized in the production of by-products, as for example green' vitriol
(crystallized ferrous sulphate) and Nordhausen sulphuric acid. Suitable propor-
tions are about equal weights of subdivided iron, water and sulphuric acid of
50° Baumé, the last being, most advantageously, somewhat in excess, say 5-8 parts
by weight sulphuric acid of 50° B. to 5 parts by weight of water and 5 parts by
weight of iron.
The full supply of acid may be introduced all at the start; but where the gas is to
be conducted through pipes to the place of utilization, it is advantageous to admit

page_text: the acid gradually to the iron, the water being first mingled with the iron, or with
the acid, or
being admitted to the iron along with the acid; and it is also advanta-
geous to control the admission of the acid by a cock, or valve, which is automatically
controlled by the bell of the gasometer, which receives the gas from the generator.
Where the gas is to be used in places which have no pipe connection with the gas
works, as in vehicles for example, or it may be in houses having no pipe connection
with the gas-works, it is considered most advantageous. to admit the whole propor-
tion of acid at the start, so as to get the compressive effect of the very energetic
chemical action which results. The gas may be stored in suitable receptacles
(suca for example as bottles composed say of strong metal tubes) under the strong
pressure effected by the chemical action. The gas may of course also be obtained
under pressure of chemical reaction by a gradual admission of the acid; but by
admitting the acid and water to the iron at the start in the predetermined pro-
portions, it is not required to introduce the acid against the high pressure which
obtains in the generator during the generation under pressure of the gas.
The invention also comprises such other, or further parts, improvements and
combinations, as are hereinafter set forth.
In the accompanying drawings,
Figure 1 is a diagram of apparatus in accordance with the invention.
Figures 2, 3, 4 and 5 are views of the generator, in front elevation, in side eleva-
tion partly in section, in bottom view and in plan respectively.
Figures 6, 7, 8 and 9 are views of a gas check and safety device, in end view,
in longitudinal section, in cross section and in side elevation respectively, and
Figures 10 and 11 are views in elevation and horizontal section respectively of
a tap, or valve, which may, with advantage, be used in some cases for regulating
the admission of acid to the generator.
Tho generator A is a vessel of suitable strength of wrought, or cast, iron, or of
copper lined with lead, provided with pipe connections as hereinafter explained
and with means for dumping the residue after running off the hydrogen for a
charge, the means shewn consisting of a bottom 7 which can be dropped to empty,
the generator of its contents.
The bottom being in place and the top uncovered, the iron is introduced in a
subdivided condition, such as iron filings, or borings, or the like. Any suitable
form of iron (wrought iron, cast iron, or other form) which will readily react with
sulphuric acid will answer. The vessel should be of such size that the full amounts 3
of iron, water and sulphuric acid, for á run, will about half fill it.
The water (to an amount equal in weight to the iron) may be let into the
generator from the elevated vessel B through the pipe 6 by opening a tap or cock
at 1 and the acid of 50° B. may be let in from the elevated vessel C through the
pipe 5 by opening a tap or cock at 3. The pipes 5 and 6 should be of lead, and 4
(especially if the liquids are to be introduced gradually) should be provided with
traps of say one, to two, metres depth, according to the back pressure under which
the gas is generated. The vessels B and C are shewn provided with gauges to
indicate the litres of liquid therein. For each five kilogrammes of iron in the
generator A, five litres of water and three and nine tenths litres of acid of 50° B. 4
(so as to give 5 kilogrammes of water and 5-8 kilogrammes of acid of 50° B. to each
5 kilogrammes of iron) may be let into the said generator either all at the start, or
gradually, as may be considered expedient. These proportions will give about a
cubic metre of hydrogen, under atmospheric pressure (760 m. of mercury).
Before allowing the hydrogen to pass to the hydrogen receiver, the lug 4 should 5
be opened until the air has escaned. Then the plug being closed, and the tap at
2 being opened, the gas passes through the washing vessels D and E and the pas
check and safety device at H to the gasometer G. The vessels D and E may be
maue of any suitable materiais (as iron, or copper, lined with lead), and may con-
tain any suitable nurifying agents such as water in the vessel D and a solution of 5
a salt of lead in the vessel E. This latter removes any sulphuretted, arseniuretted,
or phosphoretted, hydrogen, which the gas may contain.

page_text: The derice H (see Figures 6 to 9) consists of a tubular case with a series of
perforated or reticulated diaphragms a, therein, which may be made of closely
woven wire gauze, placed at short distances apart. These serve to check the flow
of the gas, so that if the generation tends to become excessive, the pressure rises in
the generator A, and (if the taps of pipes 5 and 6 are open) forces the acid out,
so that the generation of hydrogen is temporarily interrupted. The perforated
diaphragms also serve to prevent flame (in case of accident) from passing back to
the generator.
From the gasometer G the gas passes through an insulating water valve I; then
it traverses another device at M similar to the one at H and lastly passes off by the
branch pipes N. O. P to the places of utilization.
The water valve I is provided as additional means of precaution, but it may be
dispensed with if preferred.
If the production of hydrogen gas is to take place automatically, there may
be substituted for the hand-operated tap or valve 3 in the pipe 5, or be employed in
addition to such tap 3, a cock or valve as at R, so connected with the gasometer G
as to be operated thereby. When the bell of the gasometer G rises the finger 8
thereon is withdrawn so that the cock I may close and the supply of acid may be
temporarily interrupted. When the bell of the gasometer G falls, the finger 8
opens the cock R automatically and a further supply of acid flows into the generator.
Any suitable cock or valve could be used at R and any suitable connection can
be employed between it and the gasometer bell; but a special improvement consists
in a form which closes when the gasometer bell descends below a predetermined
limit. The object of this is that when the supply of acid in the vessel C (which
should be in amount proportionate to the charge of iron in the generator) is
exhausted, the pipe 5 shall be automatically closed. Referring to Figures 10 and 11
the plug of the cock I (which is preferably made of an alloy of four parts by
weight of lead and one part by weight of antimony) is connected with a bent lever S,
provided with a weight S which tends to maintain the said cock in its closed
position. On the other arm of the lever S is pivoted a finger T which can be lifted
independently of the arm of the lever S; but which when depressed carries the
lever S with it. This finger T has a depending arm provided with a weight T¹
for returning it after it has been lifted.
At the start the cock R is opened by hand, until sufficient acid has entered the
generator A to produce so much gas as to lift the bell of the gasometer G and
thereby bring the finger 8 above the finger T. Then, through the consumption, the
gasometer bell falls and the finger 8 depresses the finger T, and turns the cock
so as to admit more acid to the generator, whereupon the bell rises again, and the
weight S closes the cock R. This automatic opening and closing of the valve R
is repeated, so as to supply the acid gradually in proportion to the consumption.
When the supply of acid in the vessel C is exhausted, the bell no longer rises
after opening the cock R, but continues to descend. The finger 8, after depressing
the lever S to its full extent slips off the finger T and the weight St closes the valve.
Should the bell rise in any case after the finger 8 has passed below the finger T
this latter is free to be lifted thereby; but as soon as the finger 8 has passed upward,
the weight T brings the finger T back into the path of the said finger 8.
When it is desired to obtain hydrogen gas in receivers under strong pressure, say
from ten to fifty atmospheres, a suitable receptacle may be connected with the
generator by a pipe (provided with a tap) with or without, the interposition of
Eurifying vessels as may be necessary or expedient. When the receptacle is being
filled under pressure the tap leading to the gasometer is closed; the requisite
amounts of water and acid (as well as of iron) should have been introduced in the
generator A, before a high pressure has accumulated therein; although the liquids
could he forced in during the generation, against the pressure inside. Knowi.g
the capacity of the receiver and the pressure desired therein, it is easy to calculate
the amounts of iron, water and acid to be used from the data hereinbefore given.
At the end of the operation, the tap leading to the receptacle is closed and the com-

page_text: pressed gas in the upper part of the generator A is let into the gasometer G,' by
opening the tap 2.
Whether the hydrogen has been generated under atmospheric or superatmospheric.
pressure, the elimination of the hydrogen takes place rapidly and with a practically
complete saturation of the sulphuric acid; and there remains in the generator a
pasty mass of iron, ferrous sulphate and water, which will fall out of the generator,
without leaving, incrustation therein, and which is in such condition that it can
easily be taken away and utilized for by-products or for revivifications.
With the generator shown, the bottom 7 is dropped, and the pasty residue deposits
itself.in the receiver below. Thereupon the said generator is ready to receive a 1
new charge of subdivided iron, water and acid of 500 B.
To utilize the residue, green vitriol and Nordhausen acid (either or both) may be
made therefrom. To make green vitriol, the residue (or any desired portion thereof)
may be mixed with enough water to separate the soluble ferrous sulphate from the
insoluble residue, and the green vitriol may be crystallized out of the solution so
obtained. Or, the residue may be treated with a new supply of sulphuric acid to
convert the iron into ferrous sulphate, after the manner customary in making green.
vitriol from iron and sulphuric acid. To make Nordhausen acid, the residue is
dried and roasted. The iron in the roasted residue may be separated from the
ir oxide by sifting. This irou, or the iron which may remain after washing off
the ferrous sulphate, may be used again in the generator A as a part of a fresh
charge.
While we have specified the use of sulphuric acid of 50° B. we do not restrict
ourselves to it, since acid of higher, or lower, specific gravity may bo used, (if the
amount of water be increased, or diminished, proportionately) without altering. the
relative proportions of sulphuric acid (ISO) water (HO) and iron (Fe) in. the
generator.
We believe that we are the first to utilize a pasty mass of iron, ferrous sulphate,
and water, for the recovery of products formed by the reaction of sulphuric acid
of suitable dilution on iron, and more especially of sucli products as green vitriel
and Nordhausen acid, either or both, for which purpose, or purposes, such paste
has advantages; and such utilization we believe to be new, even if the hydrogen
gas generated by the reaction should not itself be utilized; but in conjunction with
the recovery and utilization of the hydrogen, it constitutes a further new combina-
tion or improvement.
The combination of gasometer and cock controlled thereby is not broadly new;'
but the further combination of the cock and gasometer with a hydrogen general or
containing an oxidizable metal is believed to be new; and broad novelty is believed
to exist: (irrespective of the hydrogen generator) when the combination of cock and
gasometer bell is such that the cock automatically closes when the bell sinks below
a predetermined level, and is opened and closed by the fall and rise of the Bell at
higher levels.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed wo declare that what
we claim is:-
1. The process of producing hydrogen gas, by bringing in contact with iren
such proportion of sulphuric acid and water as to form in the generator at the end
of the operation a pasty mass of iron, ferrous sulphate and water that is to say the
proportion of about equal parts by weight of iron, sulphuric acid of 50° B. aud
water, substantially as herein before described.
2. In conjunction with the bringing of iron and sulphuric acid together in such
relative proportions and with so much water as to form in the generator a pasty
mass of iron, ferrous sulphate and water at the end of the reaction, the treatment
of the said mass for the recovery of bye products, more especially green vitriol and
Nordhausen acid, either or both, the iron being recovered when thought expedient

page_text: for return to the generator as part of a new charge, substantially as hereinbefore
described.
In conjunction with the production for use of hydrogen gas by the
bringing of iron and sulphuric acid together in such relative proportions and with
so much water as to form in the generator a pasty mass of iron forrous sulphate and
water at the end of the reaction, and collecting the hydrogen gas so generated, the
treatment of said mass for the recovery of bye products, more especially green vitriol
and Nordhausen acid, either or both, the iron being recovered when thought
expedient for return to the generator as part of a new charge substantially as
lereinbefore described.
4. The process of producing hydrogen gas, by bringing in contact with iron in a
generator such proportions of sulphuric acid and water as to form in the generator
at the end of the operation a pasty mass of iron, ferrous sulphate and water and dis-
charging such paste by gravitation so as to leave the generator empty for a new
charge substantially as hereinbefore described.
5. The improvement in obtaining hydrogen gas under a pressure of several
atmospheres, by adding sulphuric acid to irou, and conducting the gas as generated
into receptacles or bottles of small capacity as compared with the volume of gas
generated, and the hydrogen gas, as generated being confined so as to be compressed'
into bottles or the like by the reaction of the sulphuric acid on the iron, substantially
as hereinbefore described.
6. In combination with a hydrogen generator supplied with an ozidizable metal,
an acid holding vessel, a supply pipe connecting the said vessel with the said
generator, a cock in the said supply pipe, a gasometer having its bell communicating
with the said generator and having a valve controlling-connection with the said
cock substantially as hereinbefore described.
7. The combination with a cock of a gasometer having its bell connected with the
said cock by means whereby on the bell sinking below a predetermined level the
cock automatically closes, and whereby also the rise and fall of the bell at higher
devels closes and opens the said cock substantially as hereinbefore described.
8. The combination with a hydrogen generator supplied with oxidizable metal,
and an acid supply pipe connected with the said generator and provided with a
cock, of a gasometer having its bell connected with the said Cock by means whereby
ou the bell sinking below a predetermined level the cock automatically closes, and
whereby also the rise and fall of the Bell at higher levels closes and opens the said
cock substantially as herein before described.
9. The cock having a weighted operating lever provided with a hinged finger
which carries the cock-operating lever with it in one direction, but is moveable
independently in the opposite direction substantially as herein before described.
10. A hydrogen-producing apparatus, composed of a dumping generator, that is
to say a generator arranged to discharge its solid contents by gravitation, together
with means for supplying the same with metal and acid, and for collecting the
hydrogen generated therein, substantially as herein before described.
11. A hydrogen producing apparatus, composed, in combination with the
5 generator, of a gasometer and connecting pipes, together with means whereby a
receiver or bottle for collecting the gas under the pressure of the chemical reaction
may be put in communication with said generator, and means for closing the
communication with the gasometer during the filling of said receiver or bottle
substantially as hereinbefore described.
00.1
1007
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.