Improvements in the Manufacture of Ammonia and Tar from Nitrogenous Organic Substances, and in Apparatus relating thereto.
Year: 1891

page_text: Date of Application, 28th May, 1891
Complete Specification Left, 15th Feb., 1892-Accepted, 19th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Ammonia and Tar from
Nitrogenous Organic Substances, and in Apparatus relating
thereto.
A communication from abroad by Dr. PAUL KUNTZE, of Aschersleben, in the
Empire of Germany.
1, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street Liverpool and 6 Bank Street, Manchester
both in the County of Lancaster and 323 High Holborn in the County of
Middlesex, Civil Engineer, do hereby declare the nature of this invention to be as
follows:--
The present invention relates to the manufacture of ammonia and tar from
nitrogenous organic substances whereby as a source of nitrogen the extensive turf*
moors and peat bogs are principally thought of.
In describing the process in detail, the moor substance or peat is mainly referred
to, but other nitrogenous substances of vegetable and animal origin may be worked
up for ammonia and tar.
The charring of peat as used up to the present yields a very incomplete
utilisation of the most valuable compound of the peat, namely the nitrogen and a
tar which is so very impure, from products of oxidation that its utilisation for
paraffin and other hydrocarbons becomes industrially impossible. By using the
present process these drawbacks are done away with and both nitrogen and bitumen
are correspondingly utilised.
The inventor has ascertained by means of many experiments that the nitrogen
in organic substances and principally that contained in peat on charring is for the
greatest part left behind in the coke. This is much more the case if the temperature
of charring is kept as low as possible and if, after driving off the tar, the raising of
the temperature is avoided. The same effect is attained by preventing the aqueous
vapours which are given off on charring the peat from acting on the hot organic
substance in the furnace. The other portion of the original nitrogen escapes on
charring in the shape of nitriles, organic bases of the pyrrol and pyridine group,
amines etc. The quantity of the organic nitrogen compounds formed, increases
with the progress of the dry distillation and at the end of the latter, when after
driving off the tar the temperature rises; nitrogen in the shape of cyanide of
ammonia appears in considerable quantities. This compound is the product of the
action of ammonia on carbon or carbonic oxide respectively which is formed in this
stage of the charring process in increasing quantities according to the following
equation
At the same time ammonia escapes along with the tarry vapours during the
progress of the dry distillation, although only in a relatively small quantity. The
greater portion of the nitrogen is on charring left behind in the coke as fixed
nitrogen, as previously mentioned.
By the present invention and the process described therein it becomes possible
to convert into ammonia not only that portion of the total nitrogen which is left.
behind in the coke as fixed nitrogen, but also that other portion which escapes
during the charring process in the form of organic nitrogen compounds. At the
same time a tar of aromatic character is obtained as a by-product, whereas or the
other hand the coke is sacrificed and serves as a source of heat. The ash of
the coke forms a very suitable substance for manure purposes, owing to its high

page_text: percentage of lime and phosphoric acid and is incomparably more valuable than the
ash of coal or brown-coal.
By keeping within the conditions previously mentioned Dr. Kuntze succeeded in
fixing the greater portion of the nitrogen of the peat in the coke during the charring
process, whereby a separation of the nitrogen which is not recoverable as ammonia
by dry distillation simply, from the tarry vapours is likewise brought about. The
fixed nitrogen which remains after the charring in the coke, can be converted into
ammonia by gasifying the coke by means of air and steam, and this is all the more
easy, the lower the temperature of the peat is kept, while the charring process is
proceeding. The amount of steam required which is mixed with the air and serves
along with the air for gasifying the coke must be nearly double the weight of the
coke, so that the gasification of the coke takes place at the lowest temperature
possible, which is yet sufficient to turn the coke into gas. The coke on burning
yielding only permanent gases which are free from tar, the present process allows
of the hot producer gases being deprived of their ammonia by acids, sulphuric acid
for instance, a fact, which technically is of the greatest importance, inasmuch, as
extensive and costly cooling towers, for the large quantity of gases are not required.
All that is necessary is a simple contrivance for mixing the hot gases with a fine
spray of water for the purpose of cooling them down to 100° C. and freeing them
from flue-dust, in order to deprive the gases of their ammonia in the acid scrubber,
while on the other hand pure solutions of ammonium sulphate are recovered which
become saturated by allowing them to run down the tower repeatedly.
Whereas, as previously mentioned, the fixed nitrogen is only converted into
ammonia in the presence of air and steam, the conversion of the nitrogen which
escapes during the charring in the shape of organic compounds into ammonia takes
place in the absence of air by an igniting process in the presence of steam and large
surfaces of hot, porous, fire-proof substances, which support the pyrogene reaction
all the more efficiently the more calcareous they are. For this purpose a porous
calcareous tar-coke is suitably used. Both kinds of recovering the ammonia agree
in that hydrogen in statu nascendi and steam in excess must always be present. The
former combines with the nitrogen, which has become disengaged from the organic
compounds, the latter serve for the protection of the ammonia formed. As a source
of hydrogen during the process of gasifying the coke on the one hand, the hydrogen
which is contained in the coke, comes in question, while on the other hand hydrogen
is formed by the action of steam on coke or carbonic oxide respectively according
to the following equations
Carbonic acid not being reduced by hydrogen a considerable excess of hydrogen is
ensured, so that the generator gas which results in the process of gasification
contains as much as from 20-30 volumes per cent. of hydrogen, and as the
formation of hydrogen is connected with a considerable absorption of heat it
becomes possible to keep the generator at a relatively low temperature, whereby
not only the dissociation of ammonia is prevented, but also the excess of heat which
is developed on gasifying the coke can be profitably applied for keeping up the
process of charring.
These are now the theoretical principles on which the new process depends. It
now remains to state the method of carrying out the process in practice. The first
step is the air-drying of the substance of moors or the turf respectively. If
unfavourable local circumstances prevent the draining of the peat-bogs, peat-presses
are employed for removing the excess of moisture. The peat-mass is then freed
from the vegetable matter lying above and worked by means of ploughs and
harrows into a homogeneous druss, which under the influence of the sun and wind
looses it adhering moisture within 2-3 hours up to nearly 30-40 per cent. As 5000
as the upper layer is dry, it is scraped together by means of a machine and

page_text: brought from the moor, onto the platform of the charring furnaces. The layer
of peat which lies below that layer which has just been removed is subjected to the
same treatment and the winning of the raw material thus proceeds horizontally in a
regular manner. The drying of the peat to powder in the air and sun allows of
great quantities of peat being quickly and cheaply worked and consequently of an
extensive production. The powdery shape of the peaty substance promotes the
charring and the gasifying process inasinuch, as the small particles of the coke offer
sufficient points of attack to the air and favour the combination of nitrogen and
hydrogen in statu nascendi. If the nitrogenous raw material has the property of
baking in the heat, it is suitable to mix it with coal druss or slack.
The air dry peat is then emptied into the furnace which in the upper part serves
for charring the peat and in its lower part for gasifying the coke. The emptying
of the air dry peat into the charring portion of the furnace is done, for instance, by
a paternosterwork. In this portion of the furnace the peat is subjected to drying
at a high temperature. The portion of the furnace which serves for charring is
similar in construction to the apparatus used in the distillation of brown-coal. The
shell of the furnace is surrounded by flues for the admission of the heating gases,
while in the inside of the furnace an empty space is formed by bell shaped rings,
one put on the top of the other. The object of the space thus created is to allow
of the escape of the vapours formed, while the material to be dried cannot find an
entrance into the inside of this empty space. In the upper portion of the bell
shaped space a horizontal partition is fixed, which, as it were, separates the drying
zone from the charring zone lying below. The aqueous vapours developed in the
drying zone pass through openings above the partition into the empty space and
are then aspirated through a pipe in order to be employed in another stage of the
same process.
The vapours of the charring zone on the other hand are aspirated
through a pipe at the bottom of the charring furnace. The object of the partition
inside the empty space is therefore the separation of the aqueous vapours of the
peat from the mixture of tarry and nitrogenous vapours which are given off during
the process of charring. The dried peat after passing the drying zone proceeds
vertically downwards into the charring zone, where it is subjected to a dry
distillation and then passing down the conical neck of the furnace it reaches the
generator which lies below the charring furnace.
The tarry and nitrogenous vapours from the charring furnace which are
aspirated through a pipe at the bottom of the charring furnace, first pass into a
retort, which is filled with calcareous, porous tar-coke and which is heated to a
light red state by means of heating gases, which are produced in the process itself.
The vapours which reach this hot retort, are decomposed by means of the heat and
the contact with the highly heated porous substances. The products of decom-
position obtained consist mainly of tar, ammonia and permanent combustible gases.
These pass first through a hydraulic main, where the tar is deposited, then through
a water-scrubber for separating tarry matters which have been driven along with
the current of gas and for removing fixed ammonia compounds, then an acid-
scrubber for absorbing volatile ammonia and lastly an oil-scrubber which is
provided with compartments after Savalle's principle in order to absorb hydro-
carbons in the oil. The resulting terminating gases-charring gases-are blown
by means of a pipe into the fireplace of the retort. The coke which passes from
the charring zone into the generator yields on gasifying with air and steam, gases
which are rich in ammonia and are carried away through a pipe from the generator.
These gases after serving for heating the air travel into a chamber which is
partially filled with water and where by means of rotating blades a finely divided
spray of water is splashed about, so that an intimate mixture of the gases with the
water spray takes place. The gases thereby cool down to 100° C., whereas flue
The
dust and all the ammonia, which is present as a salt is retained in the water.
aqueous solution is run off from time to time and the ammonia recovered from it by
means of distillation with lime. The gases thus cooled down to 100° C. then pass
through an acid-scrubber where all the ammonia is absorbed by being combined

page_text: with sulphuric acid. The addition of sulphuric acid is so regulated that the gases
only cool down by a few degrees so that only a small condensation of water can
take place. In order to render these gases, which are saturated with moisture,
suitable for heating purposes, they are, after being freed from ammonia, dried by
cooling. This is done in this way, that they are made to pass a second scrubber
which is fed with water, whereby the water cools down to 30° C. In this state
they are blown by means of a fan into the fireplace of the charring cylinder. The
cooling water which runs off from this scrubber is pumped on the top of another
scrubber where as it runs down it meets a current of air which rises upwards in the
opposite direction and is thereby warmed to from 70°-80° C. and saturated with
moisture at this temperature. This warm and moist current of air is then heated
by a recuperative system to 200°-300° C. and finely blown after being mixed with
overheated steam under the step-grate of the generator. The removing of the
ashes from the generator is done by means of a worm without interruption and is
regulated according as the coke is gasified. The angle of inclination of the step-grate
is so chosen that the coke from the charring cylinder sinks downwards as uniformly as
possible, so that the peat, which lies between the walls of the charring furnace and
the bell-shaped space in the inside of the furnace can also find its way downwards
with uniforinity, whereby the process becomes a continuous one; the time for
charring the peat and gasifying the coke being so regulated that they conform to
each other. The process as described and the apparatus as used in conjunction
with the process is not only suitable for the utilization of nitrogen in peat or turf-
substances, but can also find application for all nitrogenous organic substances. It
is specially characterised by the fact, that the vapours and volatile nitrogenous
compounds which escape on drying and charring, are carried away and treated
separately, whereas the residue of the charring process is gasified by means of
heated air and steam in order to convert the fixed nitrogen compounds into
ammonia, which ammonia is carried away and absorbed separately in order to
recover the ammonia in a pure state.
Dated this 27th day of May 1891
WM. P. THOMPSON & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Ammonia and Tar from
Nitrogenous Organic Substances, and in Apparatus relating
thereto.
A communication by Dr. PAUL KUNTZE, of Aschersleben, in the Empire of
Gerniany.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool, and 6, Bank Street, Man-
chester both in the County of Lancaster and 323 High Holborn, in the County of
Middlesex, Civil Engineer, 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 present invention relates to the manufacture of ammonia tar from nitro-
genous organic substances whereby as a source of nitrogen the extensive turf moors
and peat bogs are principally thought, of.
In describing the process in detail, the moor substance or peat is mainly referred
to, but other nitrogenous substances of vegetable and animal origin may be worked
up for ammonia and tar.
The charring of peat as used up to the present yields a very incomplete utilisation
of the most valuable compound of the peat, namely, the nitrogen and a tar which
is so very impure, from. products of oxidation, that its utilization for paraffin and
other hydrocarbons becomes industrially impossible. By using the present process

page_text: these drawbacks are done away with and both nitrogen and bitumen are corre-
spondingly utilised.
The inventor has ascertained by means of many experiments that the nitrogen
in organic substances and principally that contained in peat on charring is for a
great part left behind in the coke. This is much more the case if the temperature
of charring is kept as low as possible and if after driving off the tar, the raising
of the temperature is avoided. The same effect is attained by preventing the
aqueous vapours which are given off on charring the peat, from acting on the hot
organic substances in the furnace. The other portion of the original nitrogen
escapes on charring in the shape of nitriles, organic bases of the pyrrol and
pyridine group, amines, etc. The quantity of the organic nitrogen compounds
formed increases with the progress of the dry distillation and at the end of the
latter, when after driving off the tar the temperature rises; nitrogen in the shape
of cyanide of ammonia appears in considerable quantities. This compound is the
product of the action of ammonia on carbon or carbonic oxide respectively which
is formed in this stage of the charring process in increasing quantities according to
the following conation.
At the same time ammonia escapes along with the tarry vapours during the
progress of the dry distillation, although only in a relatively small quantity. The
greater portion of the nitrogen is on charring left behind in the coke as fixed
nitrogen, as previously mentioned.
By the present invention and the process described therein it becomes possible to
convert into ammonia not only that portion of the total nitrogen which is left
behind in the coke as fixed nitrogen but also that other portion which escapes
during the charring process in the form of organic nitrogen compounds. At the
same time a tar of aromatic character is obtained as a bye-product, whereas, on
the other hand, the coke is sacrificed and serves as a source of heat. The ash of
the coke forms a very suitable substance for manure purposes, owing to its high
percentage of lime and phosphoric acid, and is incomparably more valuable than
the ash of coal or brown-coal.
By keeping within the conditions previously mentioned, Dr. Kuntze succeeded
in fixing a great portion of the nitrogen of the peat in the coke during the charring
process, whereby a separation of the nitrogen, which is not recoverable as ammonia
by dry distillation simply, from the tarry vapours, is likewise brought about. The
fixed nitrogen which remains after the charring in the coke can be converted into
ammonia by gasifying the coke by means of air and steam, and this is all the more
easy the lower the temperature of the peat is kept, while the charring process is
proceeding. The amount of steam required, which is mixed with the air and
serves, along with the air, for gasifying the coke, must be nearly double the weight
of the coke, so that the gasification of the coke takes place at the lowest tein-
perature possible, which is yet sufficient to turn the coke into gas. The coke, on
burning, yielding only permanent gases, which are free from tar, the present process
allows of the hot producer gases being deprived of their ammonia by acids,
sulphuric acid for instance; a fact which, technically, is of the greatest importance,
inasmuch as extensive and costly cooling towers for the large quantity of gases are
not required. All that is necessary is a simple contrivance for mixing the hot
gases with a fine spray of water for the purpose of cooling them down to 100° C.
and freeing them from flue-dust, in order to deprive the gases of their ammonia
in the acid scrubber, while, on the other hand, pure solutions of ammonium sulphate
are recovered, which become saturated by allowing them to run down the tower
repeatedly.
Whereas, as previously mentioned, the fixed nitrogen is only converted into
ammonia in the presence of air and steam, the conversion of the nitrogen which
escapes during the charring in the shape of organic compounds into ammonia takes
place in the absence of air by an igniting process in the presence of steam and

page_text: large surfaces of hot, porous, fire-proof substances, which support the pyrogene
reaction all the more efficiently the more calcareous they are.
For this purpose,
a porous calcareous tar-coke is suitably used. Both ways of recovering the
ammonia agree in that hydrogen in statu nascendi and steam in excess must always
be present. The former combines with the nitrogen, which has become disengaged
from the organic compounds, the latter serve for the protection of the ammonia
formed. As a source of hydrogen during the process of gasifying the coke, on
the one hand the hydrogen which is contained in the coke comes in question, while,
on the other hand, hydrogen is formed by the action of steam on coke or carbonic
oxide respectively according to the following equations:
+ 2 H,O = CO, + H
CO + H
= CO, + Hạ
C
C.
+ H₂O
CO + H,O
=
=
Carbonic acid not being reduced by hydrogen, a considerable excess of hydrogen
is ensured, so that the generator gas, which results in the process of gasification,
contains as much as from 20-30 volumes per cent. of hydrogen, and, as the
formation of hydrogen is connected with a considerable absorption of heat, it
becomes possible to keep the generator at a relatively low temperature, whereby
not only the dissociation of ammonia is prevented, but also the excess of heat which
is developed on gasifying the coke can be profitably applied for keeping up the
process of charring.
These are now the theoretical principles on which the new process depends. It
now remains to state the method of carrying out the process in practice. The
first step is the air-drying of the substance of moors or the turf respectively. If
unfavourable local circumstances prevent the draining of the peat-bogs, peat-
presses are employed for removing the excess of moisture. The peat mass is then
freed from the vegetable matter lying above, and worked by means of ploughs and
harrows into a homogeneous druss, which, under the influence of the sun and wind,
loses its adhering moisture within 2-3 hours up to nearly 30-40 per rent. As
soon as the upper layer dry, it is scraped together by means of a machine and
brought, from the moor, on to the platform of the charring furnace. The layer of
peat which lies below that layer which has just been removed is subjected to the
same treatment, and the winning of the raw material thus proceeds horizontally
in a regular manner. The drying of the peat to powder in the air and sun allows
of great quantities of peat being quickly and cheaply worked, and, consequently,
of an extensive production. The powdery shape of the peaty substance promotes
the charring and the gasifying process inasmuch as the small particles of the
coke expose sufficient points to the action of the air and favour the combination
of nitrogen and hydrogen in statu nascendi. If the nitrogenous raw material
has the property of baking in the heat, it is suitable to mix it with coal druss or
slack.
The air-dry peat is then emptied into the furnace, which, in the upper part,
serves for charring the peat, and, in its lower part, for gasifying the coke. The
emptying of the air-dry peat into the charring portion of the furnace is done,
for instance, by a paternosterwork. In this portion of the furnace, the peat is
subjected to drying at a high temperature. The portion of the furnace which
serves for charring is similar in construction to the apparatus used in the dis-
tillation of brown coal. The shell of the furnace is surrounded by flues for the
admission of the heating gases, while, in the inside of the furnace, an empty
space is formed by bell-shaped rings, one put on the top of the other. The object
of the space thus created is to allow of the escape of the vapours formed, while
the material to be dried cannot find an entrance into the inside of this empty
space. In the upper portion of the bell-shaped space, a horizontal partition is
fixed, which, as it were, separates the drying zone from the charring zone lying
below. The aqueous vapours developed in the drying zone pass through openings
above the partition into the empty space and are then aspirated through a pipe in

page_text: order to be employed in another stage of the same process. The vapours of the
charring zone, on the other hand, are aspirated through a pipe at the bottom of
the charring furnace. The object of the partition inside the empty space is,
therefore, the separation of the aqueous vapours of the peat from the mixture of
tarry and nitrogenous vapours which are given off during the process of charring.
The dried peat, after passing the drying zone, proceeds vertically downwards into
the charring zone, where it is subjected to a dry distillation, and then, passing
down the conical neck of the furnace, it reaches the generator which lies below the
charring furnace.
The tarry and nitrogenous vapours from the charring furnace, which are
aspirated through a pipe at the bottom of the charring furnace, first pass into a
retort, which is filled with calcareous, porous tar-coke and which is heated to a
light red state by means of heating gases, which are themselves produced whilst
the process is being carried out. The vapours which reach the hot retort are
decomposed by means of the heat and the contact with the highly heated porous
substances. The products of decomposition obtained consist mainly of tar, ammonia
and permanent combustible gases. These pass first through a hydraulic main,
where the tar is deposited, then through a water-scrubber for separating tarry
matters which have been driven along with the current of gas and for removing
fixed ammonia compounds, then an acid-scrubber for absorbing volatile ammonia,.
and lastly an oil-scrubber, which is provided with compartments after Savalle's
principle in order to absorb hydrocarbons in the oil. The resulting terminating
gases charring gases-are blown, by means of a pipe, into the fireplace of the
retort. The coke, which passes from the charring zone into the generator, yields,
on gasifying with air and steam, gases which are rich in ammonia and are carried
away through a pipe from the generator. These gases, after serving for heating
the air, travel into a chamber which is partially filled with water, and where, by
means of rotating blades, a finely divided spray of water is splashed about, so that
an intimate mixture of the gases with the water spray takes place. The gases
thereby cool down to 100° C., whereas Alue dust and all the ammonia which is
present as a salt is retained in the water. The aqueous solution is run off from
time to time, and the ammonia recovered from it by means of distillation with
line. The gases thus cooled down to 100° C. then pass through an acid scrubber,
where all the ammonia is absorbed by being combined with sulphuric acid. The
addition of sulphuric acid is so regulated that the gases only cool down by a few
degrees, so that only a small condensation of water can take place. In order to
render these gases, which are saturated with moisture, suitable for heating purposes,
they are, after being freed from ammonia, dried by cooling. This is done in this
way, that they are made to pass a second scrubber which is fed with water, whereby
the water cools down to 30° C. In this state, they are blown by means of a fan
into the fireplace of the charring cylinder. The cooling water, which runs off
from this scrubber, is pumped on the top of another scrubber, where, as it runs
down, it meets a current of air which rises upwards in the opposite direction and
is thereby warmed to from 70°-80° C., and saturated with moisture at this
temperature. This warm and moist current of air is then heated by a recuperative
system to 200°-300° C., and finely blown, after being mixed with over-heated
steam, under the step-grate of the generator. The removing of the ashes from the
generator is effected by means of a worm without interruption, and is regulated
according as the coke gasified. The angle of inclination of the step-grate is. so
chosen that the coke from the charring cylinder sinks downwards as uniformly as
possible, so that the peat, which lies between the walls of the charring furnace
and the bell-shaped space in the inside of the furnace, can also find its way
downwards with uniformity, whereby the process becomes a continuous one.
The air-dry peat, treated as has been described, is then emptied for its treatment
proper into an apparatus of which Figure 1, in the accompanying drawing,
represents the furnace serving for the dry distillation and the gasification, whereas
Figure 2 shows an example of a complete plant, as it can be used in the practical

page_text: carrying out of the process. The emptying of the air-dry peat into the charring
portion A of the furnace is done, for instance, by means of a paternoster-work.
In this portion of the furnace the peat is subjected to drying at a high temperature.
The portion A of the furnace, which serves for charring, is similar in construction
to the apparatus used in the distillation of brown-coal. The shell of the furnace
is surrounded by flues k, k, for the admission of the heating gases, while, in the
inside of the furnace, a space V is formed by bell-shaped rings 9 g, one put on the
top of the other. The object of the space V thus created is to allow of the escape
of the vapours formed, while the material to be dried cannot find an entrance into
the inside of this empty space V. In the upper portion of the bell-shaped space,
a horizontal partition a is fixed, which, as it were, separates the drying zone from
the charring zone lying below. The aqueous vapours developed in the drying
zone pass through openings above the partition a into the empty space, and are
then aspirated through a pipe S, (Figure 2) in order to be employed in another
stage of the same process. The vapours of the charring zone, on the other hand,
are aspirated through a pipe B at the bottom of the charring furnace. The object
of the partition a, inside the empty space is, therefore, for the separation of the
aqueous vapours of the peat from the mixture of tarry and nitrogenous vapours
which are given off during the process of charring. The dried peat, after passing
the drying zone, proceeds vertically downwards into the charring zone, where it is
subjected to a dry distillation and then passing down the conical neck W of the
furnace, reaches the generator G which lies below the charring furnace.
As seen from the entire plant represented in Figure 2, the tarry and nitrogenous
vapours from the charring furnace, which are aspirated through a pipe B at the
bottom of the charring furnace, first pass into a retort C, which is filled with
calcareous porous tar-coke and which is heated to a light red state by means of
heating gases, which are produced in the process itself. The vapours which reach
this hot retort C are decomposed by means of the heat and the contact with the
highly heated porous substances. The products of decomposition obtained mainly
consist of tar, ammonia and permanent combustible gases. These pass first through
a hydraulic main D, where the tar is deposited, then through a water-scrubber E
for separating tarry matters which have been driven along with the current of gas,
and for removing fixed ammonia compounds, then through an acid-scrubber E for
absorbing volatile ammonia, and, lastly, an oil-scrubber which is provided with
compartments according to Savalle's principle in order to absorb volatile hydro-
carbons in the oil. The resulting terminating gases-charring gases-are blown
through a pipe X into the fire-place of the retort C. The coke which passes from
the charring zone into the generator G yields, on gasifying with air and steam,
gases which are rich in ammonia and are carried away through a pipe H from the
generator G. These gases, which, by their inherent heat, serve for heating the
air surrounding the pipes III in the chamber L, first pass through the pipes I I I
and then travel into a box K which is partially filled with water and where, by
means of rotating blades, a finely divided spray of water is dashed about, so that
an intimate mixture of the gases with the water spray takes place. The gases
thereby cool down to 100° C., whereas flue dust and all the ammonia, which is
present as fixed ammonia, is retained in the water. The fixed ammonia only forms
a small percentage of the total ammonia present. The aqueous solution is run off
from time to time, and the ammonia recovered from it by means of distillation with
lime. The gases thus cooled down to 100° C. then pass through an acid-scrubber Q,
where all the ammonia is absorbed by being combined' with sulphuric acid. The
addition of sulphuric acid is so regulated that the gases only cool down by a few
degrees, so that only a small quantity of steam condenses to water. In order to
render these gases, which are saturated with moisture, suitable for heating
purposes, they are, after being freed from ammonia, dried by cooling. This is
done in such way that they are made to pass a second scrubber R, which is fed
with water, whereby the water cools down to 30° C: The cooled gases are
aspirated through a pipe O and blown, by means of a fan Y, into the fire-place of

page_text: he charring cylinder. The cooling water, which runs off from the scrubber R, is
umped on the top of another scrubber T, where, as it runs down, it meets a
urrent of air produced by a fan Z and which rises upwards in the opposite
irection. The air is thereby warmed to from 70-80° C. and saturated with
hoisture at this temperature. The water thus cooled down is again used in the
crubber R. The warm and moist current of air, escaping from the scrubber T
hrough the pipe M, is heated by a recuperative system to 200-300° C., and, after
eing mixed with overheated steam, finally blown under the step-grate N of the
enerator. The removal of the ashes from the generator is done by means of a
vorm U without interruption and is regulated according as the coke is gasified.
Che angle of inclination of the step-grate N is so chosen that the coke from the
harring cylinder sinks downwards as uniformly as possible, so that the peat,
which lies between the walls of the charring furnace and the bell-shaped space in
he inside of the furnace, can also find its way downwards with uniformity, whereby
he process becomes a continuous one.
Having now particularly described and ascertained the nature of the said iuven-
ion and in what manner the same is to be performed, as communicated to me by
ny foreign correspondent, I declare that what I claim is:-
1. The improvements in the treatment of nitrogenous organic substances for the
production of ammonia and tar, consisting in :-
a) Subjecting the broken up and dried material to charring in a charring
furnace, which is heated by producer gases, generated at a later stage of
this process, while the resulting mixture of tarry, aqueous and nitrogenous
vapours is submitted to an igniting process, for decomposing the organic
nitrogenous vapours, in the presence of superheated steam and great surfaces
of light red hot porous refractory matter, into ammonia and hydrocarbons,
which are separated and absorbed in a well known manner; and
b) Treating the residue from the charring process in a generator situated
below the charring furnace by means of hot air and superheated steam, in
order to liberate the fixed nitrogen and convert it into animonia, the resulting
mixture of ammonia and permanent gases being separated in a well known
manner and the gases applied for heating purposes, all substantially as
described and for the purpose set forth.
2. In carrying out the process such as specified in Claim 1, arranging the
generator for gasifying the residue below the charring furnace, in order to allow
of the residue from the latter dropping directly from the charring furnace into
he generator, whereby the process becomes a continuous one, substantially as
described.
3. In an apparatus of the kind specified in Claim 2 and when used for carrying
but the hereinbefore described process, the employment of a partition a within the
bell-shaped space V of the charring furnace, in order to separate the vapours
generated in the drying zone from those given off in the charring zone, substantially
as described and for the purpose set forth.
Dated this 13th day of February 1892.
WM. P. THOMPSON & Co.,
Agents for the Applicant.