Improvements in the Production of Water-gas and in Obtaining Hydrogen, Carbonic Oxide, or Carbonic Acid each Separately therefrom, also Obtaining Certain Bye-products!
Year: 1889

page_text: Date of Application, 1st Jan., 1889
Complete Specification Left, 31st Oct., 1889-Accepted, 21st Dec., 1889
PROVISIONAL SPECIFICATION.
Improvements in the Production of Water-gas and in Obtaining
Hydrogen, Carbonic Oxide, or Carbonic Acid each Separately
therefrom, also Obtaining Certain Bye-products!
I, CARL FRIEDRICH CLAUS of 186 Suffolk House Cannon Street in the City of
London Chemist do hereby declare the nature of my said invention to be as
'follows:-
The gaseous mixture consisting principally of carbonic oxide and hydrogen which
is commonly called "Watergas" and which is now produced extensively by various
methods, forms the basis from which I obtain by the processes hereinafter described,
hydrogen, carbonic oxide or carbonic acid, each separately and in a more or less pure
condition.
I can employ the said Watergas for the purposes of my process in whatever manner
it may have been produced, but I prefer to produce it in the following manner, which
forms a part of my present Invention.
I pass an uniform and continuous stream of highly superheated steam through a
deep layer of smokeless fuel such as coke, anthracite or charcoal whereby the water is
decomposed forming according to depth of the layer of fuel or the temperature of the
incoming superheated steam either principally carbonic acid and hydrogen or
principally carbonic oxide and hydrogen, or mixtures of carbonic acid carbonic oxide
and hydrogen.
In the ordinary process of producing watergas it is the practice to fan the ignited
fuel by means of blasts of air into a state of high incandesconce, steam is then passed
through the hot fuel so long as the temperature remains sufficiently high to decompose
it into hydrogen and carbonic oxide.
After becoming too much cooled down to have this effect, the steam is shut off
and the airblast is again admitted until the desired heat is again obtained, when steam
is again admitted and so on alternately in the well known manner.
In my present improved process however I pass a continuous current of steain
previously superheated to such an extent that in passing through the fuel it maintains
therein a temperature sufficiently high to be decomposed into a gaseous mixture
consisting mainly either of carbonic acid and hydrogen or mainly of carbonic oxide
and hydrogen.
In the measure as the fuel becomes consuined by this operation, it is replenished by
fresh supplies, preferably in a state of incandescence.
A furnace or kiln similar in form or construction to a blast furnace or lime kiln
may be used as the receptacle for the fuel.
It should be built of thick brick work and be covered outside by gastight iron-work,
as should also all conduits and gas connections.
For superheating the steain used in this process I prefer to employ apparatus like
or similar to a Siemens or Whitwed regenerative and alternately working blast
heating stove though other practicable means may also be used. They are used, as
is well known, in pairs that is to say, whilst the steam is passing through one of them,
the other one is being heated up (by means of gaseous or solid fuel or by waste
furnace gases) to the requisite temperature and when the former has become cooled
down to a temperature no longer high enough for decomposing the steam in the
desired manner, the steam is shut off and turned into the one that had been heated up
in the meantime. The direction of the current of the heating gases being reversed in
a corresponding manner, is directed into the stove which has been cooled down by the
steain passing through it and so on continually with the result that one of the stoves is
always at a temperature sufficiently high for the purpose.

page_text: Both fuel receptacle and superheater are closed in at the top and are connected by
means of iron pipes thickly lined out with brickwork. The steain from any kind of
steam generator enters one of the heating stoves and after passing through it, it is
conveyed into the receptacle containing theincandescent fuel. It leaves the latter by
an exit pipe converted.
The gases produced by the action of the superheated steam upon the fuel are
either I., nearly all carbonic acid and hydrogen or II, nearly all carbonic oxide
and hydrogen or they are III. a mixture of carbonic acid and carbonic oxide with
hydrogen.
Now in order to obtain each of these gases separately I proceed as follows
I. To separate the carbonic acid from hydrogen and to obtain each separately I
may use one of two methods. If the temperature of the watergas when leaving the
fuel kiln is high enough for the hydrogen therein to reduce oxide of iron to metallic
iron I pass the gaseous mixture into one of a set of kilns or the like receptacles (say 4
or 6 in number) which are worked in rotation. They are filled with porous yet firm
pieces of oxide of iron. After passing through the first of these oxide of iron kilns
it goes into the second and so on through the whole set. The hydrogen is by this
operation eliminated from the mixture and carbonic acid alone is left. The hydrogen
having formed water with the oxygen of the oxide of iron is condensed and the
carbonic acid is conveyed into a gasholder for further use.
The heated hydrogen gas in passing through the oxide of iron converts the same
into spongy metallic iron.
The spongy iron may be reconverted into oxide of iron by passing a current of hot
air through the same but in order to obtain hydrogen gas also, I prefer to pass
Oxido of iron is thereby
a current of highly superhoated steam through the same.
formed and hydrogen gas is liberated, which is conveyed into a gasholder for
further use.
If the gaseous mixture of Carbonic acid and hydrogen issues from the watergas
generator at too low a temperature for the hydrogen to combine with the oxide of
iron or if the gas inixture has been cooled down purposely for the sake of recovering
any ammonia therefrom (as will be described hereafter), then it is heated up,
previously to its entering the oxide of iron kilns, in a regenerative or other form of
hoating stove (such as for instance the well known blast heating stove composed of
V shaped cast iron pipes heated from outside) to the temperature at which that action
is known to take place, about 400°-500° C.
The oxide of iron kilns above referred to are closed on the top (the same as the fuel
receptacles) and are connected by means of iron tubes thickly lined out with brick
work (to prevent radiation of heat). They also communicate with one another by
similar connections which are so arranged that any one of the kilns may be shunted
out of the connection with the rest.
They are further so arranged that the gaseous mixture may be turned into any one of
them and that the exit gases may be taken out of any one of them.
The hot or heated gaseous mixture named above enters one of the series and passes
As soon as the oxide of iron in the one
from it through the rest and out of the last.
into which the gaseous mixture first entered has become converted into metallic iron,
the gaseous mixture is turned off from it and passed into the next which then becomes
the first in the series and so on continually with the effect that each kiln in its turn
becomes first intermediate or last in the series. The kiln which contains the oxide of
iron converted into metallic sponge, when shunted out from connection with the rest
is then connected with the hydrogen gas-holder and highly superheated steam (super-
heated in the manner hereinbefore described) is passed into the saine. The hydrogen
gas formed thereby is conveyed into the gas holder. When the metallic iron sponge
which was contained in this kiln has by the action of the superheated stean been
again converted into oxide of iron the said kiln is disconnected from the hydrogen
gas holder and is again connected with the set of oxide of iron kilns through
which the gaseous mixture is passing and this kiln then becomes the last in the
sories.
J

page_text: The second method of separating the carbonic acid from the hydrogen is effected by
the ineans described in the Specification of a process dated October 22d 1888 and
numbered 15173 for which provisional protection has been granted to me on
December 1st 1888 and consists in absorbing the carbonic acid in ammonia whilst
passing through a series of scrubbers. The hydrogen in this case remains in the free
and gaseous state and is conveyed into a gasholder for use.
The gaseous mixture issuing from the water gas generator may as above mentioned
also consist of II, nearly all carbonic oxide and hydrogen. To separate these gases, so
that each may be utilized separately as such I pass the mixture through the oxide
of iron kilns already described and carry out the operation exactly in the same
manner as described in part I, in reference to the inixture of carbonic acid and
hydrogen.
That is to say, if the gassous mixture leaves the water gas generator at a sufficiently
high temperature for the hydrogen therein to reduce the oxide of iron to metallic
iron, but not so high as to convert the carbonic oxide into carbonic acid, I pass the
gases direct into the kilns containing the oxide of iron. If their temperature is
however not high enough, then I convey the same first through an additional heating
stove, a heating stove of the description above stated and heat the same therein to the
required temperature before passing it into the oxide of iron kilns. But should the
temperature of the gaseous mixture be so high, that the carbonic oxide therein might
be converted into carbonic acid, then I employ suitable means to reduce the tempera-
ture to the proper degree. In passing through the oxide of iron kilus under these
conditions the hydrogen of the mixture forms water with the oxygen of the oxide of
iron, and the carbonic oxide being unchanged passes through the kilns and is conveyed
to a gasholder for use.
When it is desired to convert the carbonic oxide into carbonic acid and this is to be
used as such, then I employ two methods for effecting the saine. By one of these
methods the gas mixture is heated up to or above the temperature at which oxide of
iron will convert it into carbonic acid.
For this purpose the additional regenerative heating stove already referred to is
employed through which it is passed. From thence it is carried into an additional set
of oxide of iron kilns, wherein it is converted into carbonic acid and inay then be
conveyed into a gas holder.
By the other method I pass the carbonic oxide either before or after it has entered
the gasholder together with a quantity of steam (either superheated or not) somewhat
greater in quantity than the chemical equivalent of the carbonic oxide into the
additional regenerative blast heating stove just mentioned. The heating stove having
been previously heated to an intense red heat the carbonic oxide in passing through
the same in connection with the steam becomes converted into carbonic acid, whilst
hydrogen is liberated.
To separate these two gases the above described methods may be used.
III. The water gas may consist of mixtures of carbonic oxide and of carbonic acid
with hydrogen.
To separate these the methods employed for the separation of carbonic acid only
and hydrogen and of carbonic oxide only and hydrogen and described already may be
used. Thus for instance the carbonic acid may be removed by absorbing it in aminonia
and then carbonic oxide only and hydrogen remain which may be separated as shown
already. Or the hydrogen may be removed from the mixture by the action of oxide
of iron as described and the carbonic acid separated by absorption in aminonia leaving
carbonic oxide only to be conveyed into the gas holder. Or further the hydrogen
may be eliminated from the mixture by oxide of iron and the mixture of carbonic acid
and carbonic oxide may be passed through what was called the additional set of oxide
of iron kilns and there converted wholly into carbonic acid.
Before sending the various gases named in the above description through the
regenerative heating stoves it is desirable to clear or blow out the residual heating
rases by means of a portion of the gases operated upon and then carrying them to the.
ires to be used as fuel. Contamination with nitrogen is thereby prevented.

page_text: The oxide of iron kilns in which the oxide has been converted in any part of the
processes described either by carbonic oxide or by hydrogen into spongy iron are
shunted out of the circuit and hot air or preferably superheated steam is passed
through the kiln. The hydrogen produced is conveyed into a gasholder provided for
that purpose.
By the action of the superheated steam upon the nitrogenous matter contained in
the fuel wherewith the water gas is produced, ainmonia is formed, ammonia is also
formed by the action of the steam employed in the production of the producer heating
gas, used for heating the regenerative heating stoves as practised in the above
described processes, which fact is well known.
This aminonia I propose to recover from these gases containing the same by first
cooling the gases sufficiently as they leave the generators and then by absorbing the
ammonia in scrubbers or washers by water or in sulphuric or other acids.
In the above described process the steain and the gases formed by means of the
same pass through all the apparatus mentioned in a continuous and uninterrupted
stream. All the heat required in the process is imparted to the steam itself in the
first instance and afterwards to the gases produced by the decomposition of the same.
Neither the fuel in the water gas producers is heated by external means nor the oxide
of iron in the oxide of iron kilns.
COMPLETE SPECIFICATION.
Improvements in the Production of Water-gas and in Obtaining
Hydrogen, Carbonic Oxide, or Carbonic Acid each Separately
therefrom, also Obtaining Certain Bye-products.
I, CARL FRIEDRICH CLAUS, of 186 Suffolk House, Cannon Street, in the City of
London, Chemist, 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 :-
My invention relates to the production of water-gas and to the treatment of such
gas for the separation of hydrogen, carbonic acid and carbonic oxide, in which
treatment I obtain certain by-products as hereinafter described.
The gaseous mixture consisting principally of carbonic acid, carbonic oxide and
hydrogen, which is commonly called "water-gas" and which is now produced
extensively by various methods, forms the basis from which I obtain, by the processes
hereinafter described, hydrogen, carbonic acid and carbonic oxide, each separately
and in a more or less pure condition. I can employ the said water-gas for ny
purposes in whatever manner it may have been produced, but I prefer to produce it
in the following manner, which forins part of my present invention.
I pass an uniform and continuous stream of highly superheated steam through a
deep layer of fuel, preferably smokeless fuel, such as coke or anthracite, whereby the
water or steam is deconiposed forming, according to the depth of the layer of fuel or
the temperature of the incoming superheated steam, either mainly carbonic acid and
hydrogen, or principally carbonic oxide and hydrogen, or mixtures of carbonic acid,
carbonic oxide and hydrogen.
In the ordinary mode of producing water-gas, it is the practice to fan ignited fuel
by means of blasts of air into a state of high incandescence, steam is then passed
through the hot fuel so long as the temperature reinains sufficiently high to decompose
it into hydrogen, carbonic acid and carbonic oxide. After the fuel has become too
much cooled down to have this effect, the steam is shut off and the air-blast is again
admitted until the desired heat is again obtained, when steain is again admitted, and
so on alternately in the well-known manner.
In my present improved process, however, I pass through the fuel a continuous
current of steam, previously superheated to such an extent that, in passing through
the fuel, it will cause the ignition thereof and will maintain the same at a

page_text: temperature sufficiently high to ensure the decomposition of the steam into a gaseous
mixture consisting of the gases above mentioned, no air-blast being used for pro-
moting the combustion of the fuel, and there being no necessity for previous
ignition of the fuel.
A furnace or kiln similar in forin or construction to a blast-furnace or a lime-kiln
may be used as the receptacle for the fuel. It should be built of thick brickwork
and be covered outside by gas-tight ironwork, as should also the conduits and gas-
connections.
As the fuel becomes consumed by the superheated steam, it is proportionately
replenished from the top through an opening (bell-cover or the like) and the ashes
are withdrawn from an opening (capable of being closed by a door) in the bottom of
the fuel-receptacle.
For superheating the continuous stream of steain used in this process I prefer to
employ apparatus somewhat similar to a Whitwell regenerative and alternately
working blast-heating stove. This is used in such a manner that whilst the steam is
passing through one part of it, the other part is being heated to the requisite
temperature, and, when the one part has become cooled down to a temperature no
longer high enough for decomposing the steam in the desired manner, the steam is
shut off from this part and turned into the other part that has been heated up in the
meantime. The direction of the current of the heating gases being changed in a
corresponding manner, this current is turned into the part of the stove which has
been cooled down by the steam passing through it, and so on continually, with the
result that one part of the stove is always at a temperature sufficiently high to ensure
the decomposition of the steam leaving it when this steam comes in contact with the
fuel in the aforesaid fuel-receptacle and ignites the same.
Both the fuel-receptacle and the superheater are closed in; they are connected by
Imeans of iron pipes thickly lined with brick work. Steam from any kind of steam-
generator is caused to enter the heating-stove and, after passing through it, is
conveyed into the receptacle containing the incandescent fuel, and leaves the latter by
an exit-pipo.
The
To ensure uniformity of temperature of the superheated steam, I prefer to subdivide
the stove or superheater into a series of (say 8 or 10) chambers. Each of these
chambers is filled, on Whitwell's principle, with a number of solid baffle-walls.
chambers of the stove may be of circular section (as used in connection with blast-
furnaces) but I prefer to have them of rectangular shape which permits an easier
arrangement of connections. A flue or tube lined thickly with bad conductors of
heat extends along the whole length of the chambers, conveying the heating gases to
each chainber as required, and each chamber is connected with the said flue by ineans
of branches provided with valves, which permit these gases to be admitted to any one
or more of the said chambers. The valves and their frames are water-cooled by
means of water-jackets or by means of coils of pipes cast into them. A similar
arrangement is provided for the supply of cold or hot air for the combustion of the
gases in the chambers, and also for the supply of steam. For the exit of the hot gases
(after combustion in the chambers) from one chamber to another and ultimately from
the last chainber into the chimney-flue, the same arrangement as that for the inlet of
the generator-gases may be applied. And in a like manner the steain which is being
superheated in these chambers is conveyed from one chamber to another and
ultimately from the last one into the fuel-receptacle.
As soon as one or more of the chambers are cooled down, they are shunted out from
the course of the steam and connected with the circuit of the chambers which are
being heated by the generator-gases. When heated to the required temperature they
are again connected with the steam-circuit, and a corresponding number of cooled
chambers are simultaneously connected with the circuit of the heating gas, and so on
continually. The gases and the steam to be heated travel in the saine direction
through the chambers. In this manner, a number of chambers are continually being
heated, whilst an equal number of chambers are having their stored up heat abstracted

page_text: by the steain passing through them. The working is analogous to that of annular
brick-kilns..
After the heating of the chambers, they are full of the products of combustion of
the producer-gas. To prevent the water-gas heing contaminated by the same, a
blast of steain is sent through the said chambers to drive out the said products of
combustion before the re-admission of steain to be superheated. This may be done by
the steam-blast entering direct, but I prefer to do so by first passing the steam
through the ordinary generator and then through the chambers, the air supply to the
said ordinary generator being stopped for the time and whilst the steam-jet passing
through is being used for the purpose named.
My object is to obtain the whole of the water-gas produced, for use for the purposes
for which it is manufactured, and not to use any of this gas for heating the chambers
or regenerators. I therefore effect the heating of the Whitwell or any other steam-
superheating stoves which may be employed for the purpose, by means of less valuable
ordinary producer-gas, obtained in the well-known manner from any kind of fuel
either with or without the aid of stoam, and I do not use any part of the water-gas
produced for heating any of the apparatus connected with its manufacture. I thus
obtain nearly double the quantity of the more valuable water-gas than is usual in the
ordinary mode of working.
The gases which are produced by the action of the superheated steam upon the fuel
are either:
1. Principally carbonic acid and hydrogen, or
2. Principally carbonic oxide and hydrogen, or
3. A mixture of carbonic acid and carbonic oxide and hydrogen. These are all
accompanied by the ammonia which is simultaneously formed by the action of the
superheated steam upon the nitrogenous matter contained in the fuel wherewith
the water-gas is produced.
By using steam alone and dispensing with an air-blast acting upon the fuel, and by
passing the steam in a continuous current through the fuel, the whole of the fuel is
consumed by the steam alone and practically the whole of the nitrogen in the same
is converted into ammonia available for recovery by the process hereinafter described,
instead of only a portion of it, as is the case in the processes hitherto in use; this [
ain enabled to accomplish, since I do not use an air-blast nor do I use any portion of
the water-gas for heating the superheating stove.
To separate the carbonic acid from the hydrogen or from mixtures of carbonic acid,
carbonic oxide and hydrogen, and to recover at the same time the ammonia above
referred to, I first reduce the temperature of the mixed gases. This I carry out by
employing the heat inherent in the gases after they leave the generator, in the two
operations to be described below, viz. in the heating of the ammoniacal scrubber-
liquor, and in distilling the same after it has been heated by means of this heat.
The gases become cooled by these operations. After they are thus cooled they are
passed through a series of scrubbers wherein they are brought in contact with free
aumonia either in a gaseous or a liquid state, whereby the carbonic acid becomes
absorbed, whilst a solution of carbonate or sesqui-carbonate of ammonia is formed.
The residual hydrogen or carbonic oxide and hydrogen gas is conveyed into a gas-
holder. The solution of carbonate of ammonia formed in the scrubbers is then heated
by the hot gases as will be more fully described below. The greater part of the
carbonic acid is thereby driven out and collected in a gas-holder for use, and the free
ammonia left behind in the liquid is distilled off by means of the hot gases and is
returned to the scrubbers to there take up more carbonic acid from a fresh quantity
of gases, a certain stock of ammonia being kept in constant circulation throughout all
the apparatus for that purpose. Having given the outline of this process, I will
proceed to more fully describe the same.
Presuming the gaseous mixture to have been cooled sufficiently by the means
above indicated, it is conveyed into the sories of scrubbers above referred to and is
caused to travel through the same either by its own pressure or by the aid of fans. I

page_text: will assume that five of these scrubbers are employed. Washers or similar apparatus
may be used instead of the scrubbers.
The gas enters at the foot of the first scrubber, rises upwards in it and leaves
it at the top, to be conveyed by a connecting pipe into the bottom of the next
scrubber, and so on through all of them. Into the second scrubber, free ammonia
either in the gaseous or in the liquid form is conveyed, which combines with the
carbonic acid in the gas, forming carbonate or sesqui-carbonate therewith. Through
the last, the fifth scrubber water is showered by means of any of the well known
distributors, which arrests any ammonia which might otherwise pass away with the
gases on leaving the scrubbers. But to reduce it to a certainty that no ammonia
shall pass away, the gases are caused to pass through a lead-lined tower, the
contents of which (coke or the like) are moistened with sulphuric acid, whereby a
solution of sulphate of ammonia is produced.
The liquid which collects on the bottom of the fifth scrubber is lifted by means
of a constantly working pump on to the next, the fourth scrubber, the contents of
which are likewise moistened, and on arrival at the bottom of this scrubber, it is
pumped on to the next, and so on until it has passed through and washed down
all the scrubbers of the series. The course of the liquid is consequently in the opposite
direction to that of the gases, that is to say, from the last to the first, that of the gases
being from the first to the last.
The gases in their passage through the scrubbers become gradually poorer and
poorer in carbonic acid, whilst the liquid takes up on its way more and more
carbonate of ammonia. In the second scrubber or in the scrubber into which the
free ammonia is introduced, the liquid still contains free ammonia, which, on
arriving at the bottom of the first scrubber, into which the gases first enter and
where they still contain the most of their carbonic acid, should, with proper care,
be converted into sesqui-carbonate.
The admission of the gases to the first and of the ammonia to the second (or other)
scrubber should be so regulated that, on the one hand, little or no carbonic acid
should pass away with the gases from the last scrubber, and that, on the other hand,
the liquid leaving the bottom of the first scrubber should be well saturated with
carbonic acid, so as to form a solution of sequi-carbonate of ammonia. Water is
supplied to the last scrubber in such quantities that this liquid contains at least two
per cent., but not more than ten per cent., of ammonia.
The liquid which collects at the bottom of the first scrubber is conveyed by a
constantly working pump to another part of the plant employed in this process. This
plant consists of several parts, viz. in absorbing tower, a condensing tower, a wash-
tower, a heating-apparatus and a distilling-tower. In this plant, the carbonic acid
which was removed from the water-gas by aninonia, is expelled by heat and collected
in a gas-holder, the free ammonia left behind is again returned from hero to the
scrubbers to take up fresh quantities of carbonic acid, and, in the saine plant, is also
recovered the ammonia which was produced by the action of the superheated steam
upon the fuel in the water-gas generator or fuel-receptacle. The liquid passes to the
top of the condensing tower and trickles through the same. (This apparatus is con-
structed and manipulated similar to a scrubber.) From the bottom of this tower, the
liquid runs into the heating apparatus, which consists of a number of shallow tanks
closed on the top, which are superimposed upon one another, but connected with one
another by communicating tubes. An intervening space is left between the top and
bottom of adjacent tanks and the whole set is enclosed in a steam-chest furnished with
an inlet and an outlet pipe through which the hot water-gas is conveyed as it leaves
the water-gas generator. Passing through the intervening spaces mentioned, the
water-gas gives up its heat to the contents of the shallow tanks and passes away from
the heating chest inuch cooler than it entered the same. The liquor runs from the top
of this tank through the whole set of them until it reaches the lowest one. The
flow of the liquor is so regulated that it assumes in the uppermost tiers a temperature
of about 180° to 190° Fahrenheit which may rise in the lowest ones to 195° to 200°
Fahrenheit or slightly higher still.

page_text: I do not confine myself to this or any other construction of apparatus for heating
the said liquor, nor does this apparatus form a part of my invention, but I find it
suitable for carrying on my process. Multitubular tanks, for instance, might be
substituted for those just above described. The effect of heating the liquor in the
manner above described is that the greater part of the carbonic acid previously
combined with the ammonia leaves the same in the free state accompanied with
only a proportionately small quantity of ammonia, which passes together with the
carbonic acid from the heating apparatus, by a connecting pipe, into the condensing
tower. They ascend this tower, inesting on the way upwards the shower of cooled
scrubber-liquor, in which the greater part of the ammonia is retained. The free
carbonic acid together with a small remnant of ammonia then passes through a
connecting pipe into the bottom of the next apparatus, the washing-tower, wherein
it is freed from the remaining ammonia by water which is caused to trickle down
this tower. The liquid thus forined is pumped from the bottom of the wash-tower
to the top of the condensing tower, which it descends in company with the cooled
liquor from the first gas-scrubber. To ensure that no ammonia whatever shall pass
away with the free carbonic acid, it is carried through a lead-lined tower, the
contents of which are moistened with sulphuric acid, before it is collected in a gas-
holder for use, thus producing a solution of sulphate of ammonia. Should the
carbonic acid gas be found to contain any sulphide of hydrogen which it is desired
should be removed therefrom, the carbonic acid is passed, previous to its entering the
gas-holder, through hydrated oxide of iron purifiers.
In the liquid which collects at the bottom of the heating apparatus, the larger
This is
proportion of the ammonia which it contains exists in the free state.
returned to the scrubbers in order that it may take up further quantities of carbonic
acid from fresh quantities of gases. The liquor containing the free ammonia might
be used, after being cooled, for taking up fresh quantities of carbonic acid in the
scrubber by moistening the same therewith, but as, by the constant accession of
more water to the saine from the washing-scrubbers, it would soon become too
diluted to be of any use, I prefer to return it to the scrubbers in a more concentrated
form. For this purpose I distil or concentrate the same as hereinafter described,
viz. The hot liquor from the heating apparatus is pumped to the top of the distilling
tower (which may be constructed and worked like a gas-scrubber, but a Coffey still or
similar apparatus will answer the purpose); it is made to descend within the said tower,
thus meeting in its descent a current of hot water-gas from the water-gas generator,
previous to this gas entering the scrubbers, which gas passes through the towers in an
upward direction. To effect the cooling of the hot water-gas by means of the
ammoniacal liquor, the whole of the water gas may be passed through the heating
apparatus and thence through the distilling tower, or it may be passed through the
distilling tower first and then through the heating tower previous to its entering the
scrubbers, or it may be split up into two parts one part going one way and the other
part going the other way. Before entering the scrubbers, however, it is further
cooled down and the steam accompanying it condensed by means of a multitubular
cooler, the cooling liquid being either scrubber-liquor (whilst passing from the
scrubber to the condensing tower) or cold water. The liquid forined by condensation
is run back into the top of the distilling tower, so that froin the latter mostly ammonia
in the gaseous forms passes into the second scrubber.
A portion of cooled water-gas is made to enter the first scrubber to permit the
carbonic acid contained in such gas to neutralise any free ammonia which might be
present in that scrubber.
The stream of ammonia liquor through the tower is so regulated that, when it
arrives at the bottom of the same, it is perfectly free from volatile ammonia. The
exhausted liquor is then cooled and used instead of water for supplying the wash-
scrubber. Fixed salts of ammonia gradually accumulate by long use in this liquor
which should from time to time be removed from the same by lime in the well-known
manner.

page_text: The ammonia driven out of the liquor in the distilling tower by the hot water-gas
passes along with the water-gas into the scrubbers.
A certain stock of ammonia is kept in constant circulation through the apparatus
above referred to, but whatever quantity of ammonia is introduced from outside
sources, is removed from the circulation. A quantity of ammonia equivalent to that
which is produced by the action of the superheated steam upon the fuel in the water-
gas generator is constantly removed in the gaseous form or in the form of vapour, by
means of a connecting pipe, from the apparatus heroin called the condensing tower,and
conveyed into the absorbing tower wherein it is absorbed into cold water. It loaves
this tower as a strong solution of sesqui-carbonate of ammonia.
I find it advantageous to carry on the manufacture of water-gas in conjunction
with the process known as the ammonia-soda process; in this case the froo ammonia
generated in that process by the action of lime upon chloride of ammonium is
conveyed into the scrubbers for the two-fold purpose of removing the carbonic acid
from the water-gas contained therein, and converting the free aminonia into a strong
solution of sesqui-carbonate of ammonia; then (in addition to the ammonia derived
from the fuel and already contained in the gas) a quantity of sesqui-carbonate of
ammonia equivalent to the free ammonia so introduced is removed from the
condensing tower and conveyed into the absorbing tower for use in the ammonia-
soda process.
This cheap and advantageous process of removing carbonic acid from water-gas
and of rendering it useful, I turn to further advantage in the following manner,
viz. To obtain water-gas with a high percentage of carbonic acid, a very much
lower temperature than that ordinarily employed, is required for its formation. I
therefore purposely obtain, by employing steam superheated to a lower temperature
than is usual, a water-gas of that description. By removing this large quantity of
carbonic acid from the said water-gas in the manner above described, I obtain a gas
which is very much richer in hydrogen than is usual.
In the above described process, the steam and the gases produced thereby pass
through all the apparatus in a continuous uninterrupted stream.
All the heat required in the process is imparted to the steam itself and to the
gases produced by the decomposition thereof. There is no heat applied to the outside
of the apparatus.
My principal object in using no air-blast and only ordinary generator-gas or
ordinary fuel of any other kind for heating the steam-superheating stove, is that I
may be able to obtain and recover in the process, as described, practically the whole
of the aminonia formed by the action of the superheated steam upon the nitrogen of
the fuel operated upon in the water-gas generator,that is to say, a quantity of aminonia
nearly double that obtained in the usual way.
In the above description, I have shown in what manner carbonic acid is to be
separated from hydrogen and from mixtures of carbonic oxide and hydrogen, and the
ammonia recovered as sesqui-carbonate or carbonate or sulphate of ammonia.
I will now describe how I propose to separate carbonic oxide and hydrogen and to
obtain them separately.
When water-gas is produced which contains carbonic acid, or when it has
intentionally been produced with a large percentage of CO, and such CO, has been
removed froin it by the process above described, and the ammonia (which may have
been associated with it in one way or another) has been removed and recovered from
it, the two residual gases carbonic oxide and hydrogen have by that operation been
cooled down.
They are then heated up again to a temperature somewhat above that at which
hydrogen will reduce oxide of iron (say to about 400° to 500° Centigrade) but below
that at which carbonic oxide will do so.
The heating of the gaseous mixture may either be accomplished by means of a
heating stove such as that above described for the superheating of the steain, or, as
the temperature required is a comparatively low one, it may be done in the well-
known blast-heating stoves used in connection with the blast-furnaces, and whic

page_text: consist of a number of inverted U-shaped pipes, which are well-known and need not
here be described in detail. Waste furnace-gases may be used for heating these
stoves. When the gaseous mixture has been heated up to the temperature above
mentioned, I pass it into one of a set of say six, eight or more kilns or chambers
which are filled with porous, yet firm pieces of oxide of iron and which are worked in
rotation. After passing through the first of these oxide of iron kilns, the gaseous
mixture passes into the second, and so on through the whole series. The hydrogen is
by this operation separated from the carbonic oxide, by forming water with the oxygen
of the oxide of iron and spongy metallic iron. The water formed is condensed and
the carbonic oxide is conveyed to a gas-holder for use.
The oxide of iron kilns are closed kilns, they are connected, however, by means of
iron tubes thickly lined by bad conductors of heat. They communicate with one
another by connecting pipes which are so arranged that any one or more of the kilns
may be shunted out of connection with the others by means of valves. They are
further so arranged that the gaseous mixture may be turned into any one of them,
and, by similar means, that the exit gases may be taken out of any one of them.
The heated gaseous mixture enters one kiln of the series, and the part of the said
mixture which passes through the said kiln, enters the next kiln, and so on, the gas
from the last kiln passing into a gas-holder. As soon as the oxido of iron in the kiln
into which the gascous mixture first entered, has become converted into metallic iron,
the gaseous mixture is turned off from this kiln, and is turned into the next kiln,
which thus becomes the first in the series, and so on continually, with the effect that
each kiln in its turn becomes first, intermediate or last in the series. The kiln which
contains the oxide of iron converted into metallic iron sponge, when shunted out from
connection with the other kilns, is then connected with the hydrogen gas-holder, and
highly superheated steam (superheated in the manner hereinbefore described) is
passed into the same. The hydrogen gas formed thereby is conveyed into the gas
holder. The superheated steam is, however, with more advantage passed successively
through several of the kilns which contain the metallic sponge. It enters the one
which was connected with the heated gases first and leaves the one which was
connected last with the said heated gases.
When the metallic iron sponge which was contained in these kilns has, by the
action of the superheated steam, been converted into oxide of iron, the first of the said
kilus is disconnected from the hydrogen gas-holder and is again connected with the
set of oxide of iron kilns, through which the gaseous mixture is passing, and this kiln
then becomes the last in the series, a modus operandi the advantages of which will be
understood by manufacturers without further description.
I do not confine myself to any particular construction of the apparatus which is
herein described.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I wish it understood that I
claim:
-
First. The production of water-gas, without the use of an air-blast in the water-
gas generator, by passing through the fuel a continuous current of steam previously
superheated in a stove heated by ordinary generator-gases or by solid fuel or fuel-
gases and not by a part of the water-gas itself.
Second. The improved method of superheating steam by the use of a heating stove
divided into a series of chambers which are worked in succession, the heating gases
and steam alternately passing through them, substantially as, and for the purpose,
above specified.
Third. The separation of carbonic acid from water-gas by means of gaseous or liquid
ammonia.
Fourth. The separation of carbonic oxide from hydrogen, in the above named
gaseous mixture, by the conversion of the hydrogen into water by means of oxide o
iron and the reproduction of hydrogen from steam by the action of the spongy iron
simultaneously formed in the said process.

page_text: Fifth. The employment of a number of kilns filled with oxide of iron worked in
succession, as described, for removing hydrogen from carbonic oxide and for
reproducing hydrogen, as above specified.
Sixth. The recovery of the ammonia from the water-gas in the form of a strong
solution of carbonato."
Seventh. The recovery of ammonia in the form of carbonate of sulphate from the
nitrogen of the fuel employed in the manufacture of water-gas, by producing such
gas without the use of an air-blast and then separating the ammonia-from the said
gas, substantially as hercinbefore described.
Eighth. The herein described method of cooling the water-gas by imparting the
heat thereof to the ammoniacal liquor, for the purposes above specified.
Ninth. The utilization of the free ammonia produced in the ammonia-soda process
for removing carbonic acid from water-gas and thus forming carbonate or sesqui-
carbonate of ammonia.
Tenth. The manufacture of water-gas in connection with the ammonia-soda process
in such a manner that the free ammonia from the said process is used for removing
the carbonic acid from the water-gas and the carbonate of aminonia and free carbonic
acid recovered from the said gas, are utilized in the said process. substantially as
hereinbefore described.
Eleventh. The removal of carbonic acid from water-gas by means of a constant
stock of ammonia kept in continual circulation through the apparatus used for the
purpose.
Twelfth. The manufacture of water-gas rich in carbonic acid by passing through the
fuel steam superheated to a comparatively low temperature,substantially as, and for
the purpose, above specified.
Dated this 31st day of October 1889.
C. F. CLAUS.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, Agents for the Applicant.