IMPROVEMENTS IN THE METHOD OF OBTAINING AMMONIA, TAR, AND OTHER PRODUCTS OF DISTILLATION FROM THE GASES OF COKE OVENS, AND IN APPARATUS EMPLOYED FOR SUCH PURPOSE
Year: 1881

page_text: ETTERS PATENT to John Clayton Mewburn, of 169, Fleet Street, in the
City of London, Patent Agent and Consulting Engineer, for an Invention of
"IMPROVEMENTS IN THE METHOD OF OBTAINING AMMONIA, TAR, AND OTHER
PRODUCTS OF DISTILLATION FROM THE GASES OF COKE OVENS, AND IN
APPARATUS EMPLOYED FOR SUCH PURPOSE." A communication from abroad
by Theodor Scholz, Merchant, and Franz Stroehmer, Engineer, both of
Dresden, Saxony.
PROVISIONAL SPECIFICATION left by the said John Clayton Mewburn at
the Office of the Commissioners of Patents on the 14th February 1881.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN THE METHOD OF OBTAINING
AMMONIA, TAR, AND OTHER PRODUCTS OF DISTILLATION FROM THE GASES OF
COKE OVENS, AND IN APPARATUS EMPLOYED FOR SUCH PURPOSE." [A com-
munication from abroad by Theodor Scholz, Merchant, and Franz Stroehmer,
Engineer, both of Dresden, Saxony.]
Coke ovens in which the side walls as well as the bottom of the oven are heated
almost uniformly by the gases, which gases are afterwards conducted to the
chimney (as is the case in the systems of Smet, Gobiet, Bexroth, François, Copée,
Buettgenbach, Wintzek, and others) have proved to give satisfactory results.
These ovens will therefore be mostly employed in future for producing coke.
The object of the present Invention is to apply to these ovens a method of
obtaining tar and ammonia in order to combine the best return of coke and the best
production of ammonia and tar.
For the evacuation of the gases from the coke ovens I use the charging or
filling apertures of the ovens, with which apertures side channels communicate
within the top wall of the oven.
These side channels communicate with a vertical tube made of cast iron, wrought
iron, or any other suitable material lined with refractory stone or fire clay bricks,

page_text: which tube may be closed at the bottom by a damper. The upper part of this
tube, which it is preferred to make of cast iron, is fitted with a well closing throttle
valve, which for sake of complete and tight fitting may be provided with a ring of
felt or asbestos.
By means of the said damper and throttle valve I am enabled to produce as
much as possible a hermetic seal between the oven and the main pipe, hereinafter
mentioned.
In order to protect the hot evacuated gases from decomposition, and in order to
accelerate their cooling, I cause a fine jet of steam to enter the vertical tube. This
jet may be blown down or extended according to circumstances, and according to
the heat of the oven, and according to the progress of the coking process as far as
the coals.
1
When the coking process is too slow and the heat too small, I may cause a
second fine jet of steam to enter at the lower part of the vertical tube in an
upward direction with the evacuating gases, by which jet the process in the oven
may be accelerated.
By means of this double arrangement of introducing steam, that is, in the
direction in which the evacuating gases flow and in the opposite direction, I am
enabled to easily regulate the pressure and the draught in the oven in a more
perfect manner than has been hitherto attained.
The steam entering the vertical tube will prevent the walls of this tube becoming
overheated, and will mix so perfectly with the gases that a great part of the heat.
of the gases will be fixed by it.
To this double entrance of steam into the evacuating tubes or channels I add,
for the purpose of increasing the result in obtaining ammonia, several steam pipes
leading through the masonry of the partition walls, and surrounded by fire clay
bricks or bauxite down to the bottom of the ovens, by which pipes I introduce
highly superheated steam directly into the burning coals if the progress of coking
has already advanced to a certain stage.. This steam introduced in a superheated
condition will, in coming into contact with the burning coals, become decomposed
into hydrogen and oxygen.
The oxygen in contact with the coals will form carbonic acid, which, by
penetrating the upper layer of coals, will be reduced to carbonic oxide, whereas
the freed hydrogen will combine with the nitrogen present, and form ammonia.
The above mentioned vertical evacuating tubes of the different ovens com-
municate either directly into a main pipe which is common to a series of ovens,
and which may be supported by the vertical tubes; or these latter may enter
sideways into the main pipe. Corresponding with the entrance of each evacuating
tube into the main, an aperture is provided into the latter at its upper side for
cleaning the said tubes; these apertures may be closed by plates with clay and
asbestos. The main pipe from its upper end down to the condenser with which
it communicates is mounted in an inclined position, so as to cause all products of
condensation to flow towards this condenser.
The condenser is composed of a series of cast iron vertical pipes in combination
with lower horizontal pipes for collecting the products of condensation. These
products may flow off by end pipes which are provided with a U formed pipe into
the reservoirs for the tar and ammoniacal water. The number of series of pipes
may vary according to the quantity of gas to be evacuated. The whole condenser
is surrounded by a reservoir of wood, or iron, or masonry, into which cold water
enters at the lower part, while the heated water flows off at the upper part. By
the arrangement above described I cause the products of condensation which
collect in the lower horizontal pipes to be drawn off separately, and I thus gain
the different tars analogous to a fractional distillation. At the end of the condenser
the products which contain more volatile oils will collect, whereas the heavier
products containing the heavier oils and pitch will collect in the first pipes.
Beyond the condenser I place one or more very effective steam jet apparatus
according to the quantity of gas to be evacuated, so as to cause sufficient evacua-

page_text: tion in the whole series of ovens. The steam of the jet apparatus mingling with
the evacuated gases is eliminated from the gases by known devices, either by
cooling, or by injection of water, or by long pipes. The cooled gases composed of
hydrogen, of carbon, carbonic oxide, and some carbonic acid, which gases are of
high value for burning or heating purposes, may be conducted a considerable
distance, and utilized for heating steam boilers or for other purposes.
The following mode of working has been found very advantageous:-
Each alternate oven of the series, which I will call oven A, having been filled
afresh with coals, is brought into communication with the evacuating device, that
is to say, the throttle valve and the damper are opened, and a slight jet of steam
is admitted in the direction in which the gases flow. In the adjacent oven, which.
I will call B, the damper and throttle valve are closed as well as the damper which
leads to the flue communicating with the chimney. This oven communicates with
oven A by the bottom channels, and sends its very hot gases first underneath its
own bottom, and from there underneath the bottom of the freshly filled oven A,
which gases will afterwards rise in the wall flues of the latter oven, thereby heating
the bottom and the walls of the freshly filled oven, and the gases will be evacuated
with the gases of this oven.
Now if the gases from oven B become too low, which may be indicated by a
pressure gauge, the damper communicating with the chimney must be opened as
far as necessary, so as to prevent the stopping or cooling of this oven, but to
allow of the temperature necessary for the coking.
After oven A. has gone through half its process of coking, the adjacent oven B,
which has finished its coking process, is emptied and filled afresh, after which the
ovens change their duty, the throttle valve damper in the evacuating tube of
oven A being shut, and these parts of oven B being opened, by which means
the gases will now circulate in the opposite direction.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Clayton Mewburn in the Great Seal Patent Office on the
13th August 1881.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London, Patent
Agent and Consulting Engineer. "IMPROVEMENTS IN THE METHOD OF OBTAINING
AMMONIA, TAR, AND OTHER PRODUCTS OF DISTILLATION FROM THE GASES OF
COKE OVENS, AND IN APPARATUS EMPLOYED FOR SUCH PURPOSE." (A com-
munication from abroad by Theodor Scholz, Merchant, and Franz Stroehmer,
Engineer, both of Dresden, Saxony.)
Coke ovens in which the side walls as well as the bottom of the oven are heated
almost uniformly by the gases, which gases are afterwards conducted to the
chimney (as is the case in the systems of Smet, Gobiet, Bexroth, François, Copée,
Buettgenbach, Wintzek, and others) have proved to give satisfactory results.
These ovens will therefore be mostly employed in future for producing coke.
The object of the present Invention is to apply to these ovens a method of
obtaining tar and amnionia in order to combine the best return of coke and the
best production of ammonia and tar. The accompanying Drawings represent the
apparatus which I employ for the purpose.
Figure 1 is a transverse section of the apparatus on the line V. VI. of
Figure 2; Figure 2 is a longitudinal section on the line I. - - II. of Figures 1
and 3; Figure 3 is a horizontal section or ground plan on the line III. - - IV. of
Figure 1; Figure 4 is a transverse section of the condenser employed in com-
bination with the coke oven on the line E- F of Figure 6; Figure 5 is a
longitudinal section on the line CD of Figures 4 and 6; Figure 6 is a hori-
zontal section or ground plan on the line A B of Figure 4.
--
-->
For the evacuation of the gases from the coke ovens I use the charging or filling
apertures of the ovens, with which apertures side channels a, a, communicate
within the top wall of the oven.
These side channels communicate with a vertical tube b made of cast iron,
wrought iron, or any other suitable material lined with refractory stone or fire
clay bricks, which tube may be closed at the bottom by a damper c.. The upper
part of this tube, which it is preferred to make of cast iron, is fitted at d with a
well closing throttle valve, which for sake of complete and tight fitting may be
provided with a ring of felt or asbestos.
By means of the said damper and throttle valve I am enabled to produce as
much as possible a hermetic seal between the oven and the main pipe herein-
after mentioned.
In order to protect the hot evacuated gases from decomposition, and in order to
accelerate their cooling, I cause a fine jet of steam e to enter the vertical tube.
This jet may be blown down or extended according to circumstances, and according
to the heat of the oven, and according to the progress of the coking process as far
as the coals.
When the coking process is too slow and the heat too little, I may cause a
second fine jet of steam f to enter at the lower part of the vertical tube b in an
upward direction with the evacuating gases, by which jet the process in the oven
may be accelerated.
By means of this double arrangement of introducing steam, that is, in the
direction in which the evacuating gases flow and in the opposite direction, I am
enabled to easily regulate the pressure, and the draught in the oven in a more
perfect manner than has been hitherto attained.
The steam entering the tube b will prevent the walls of this tube becoming
overheated, and will mix so perfectly with the gases that a great part of the heat
of the gases will be fixed by it.

page_text: To this double entrance of steam into the evacuating tubes or channels I add,
for the purpose of increasing the result in obtaining ammonia, several steam pipes g
leading through the masonry of the partition walls and surrounded by fire clay
bricks or bauxite down to the bottom of the ovens, by which pipes I introduce
highly superheated steam directly into the burning coals if the process of coking
has already reached a certain stage. This steam introduced in a superheated
condition will on coming into contact with the burning coals become decomposed
into hydrogen and oxygen. The oxygen in contact with the coals will form
carbonic acid, which by penetrating the upper layer of coals will be reduced to
carbonic oxide, whereas the freed hydrogen will combine with the nitrogen present
and form ammonia.
The above mentioned vertical evacuating tubes b, b, of the different ovens
communicate either directly into a main pipe h which is common to a series of
ovens, and which may be supported by the tubes b, or these latter inay enter
sideways into the main pipe. Corresponding with the entrance of each evacuating
tube into the main, an aperture is provided in the latter at its upper side for
cleaning the said tubes; these apertures may be closed by plates with clay and
asbestos. The main pipe h from its upper end down to the condenser
Figures 4, 5, and 6) with which it communicates is mounted in an inclined position,
so as to cause all products of condensation to flow towards this condenser.
(see
The condenser k, shewn in Figures 4, 5, and 6, is composed of a series of vertical
cast iron pipes 7, in combination with lower horizontal pipes m for collecting the
products of condensation. These products may flow off by end pipes n, which are
provided with a U formed plate into the reservoirs for the tar and the ammoniacal
water. The number of series of pipes may vary according to the quantity of gas
to be evacuated. The whole condenser is surrounded by a reservoir of wood or
iron, or masonry, into which cold water enters at the lower part while the heated
water flows off at the upper part. By the arrangement above described I cause
the products of condensation which collect in the lower horizontal pipes to be
drawn off separately, and I thus gain the different tars analogous to a fractional
distillation at the end of the condenser the products which contain more volatile
oils will collect, whereas the heavier products containing the heavier oils and pitch
will collect in the first pipes.
Beyond the condenser I place at one or more very effective steam jet apparatus
according to the quantity of gas to be evacuated, so as to cause sufficient evacuation
in the whole series of ovens. The steam of the jet apparatus mingling with the
evacuated gases is eliminated from the gases by known devices, either by cooling
or by injection of water, or by long pipes. The cooled gases composed of hydrogen
of carbon, carbonic oxide, and some carbonic acid, which gases are of high value for
burning or heating purposes, may be conducted a considerable distance and utilized
for heating steam boilers or for other purposes.
The following mode of working has been found very advantageous :-Each
alternate oven A of the series having been filled afresh with coals is brought into
communication with the evacuating device, that is to say, the throttle valve d and
the damper c are opened, and a slight jet of steam is admitted at f in the direction
in which the gases flow. In the adjacent oven B the damper c and throttle valve d
are closed as well as the damper 2 which leads to the flue 9 communicating with
the chimney. This oven communicates with oven A by the bottom channels r, s, t,
and sends its very hot gases first underneath its own bottom, and from there under-
neath the bottom of the freshly filled oven A, which gases will afterwards rise in
the wall flues of the latter oven, thereby heating the bottom and the walls of the
freshly filled oven, and the gases will be evacuated with the gases of this oven.
Now if the gases from the oven B become too low, which may be indicated by a
pressure gauge, the damper p communicating with the chimney must be opened as
far as necessary, so as to prevent the stopping or cooling of this oven, but to allow
of the temperature necessary for the coking.
After oven A has gone through half its process of coking, the adjacent

page_text: oven B which has finished its coking process is emptied and filled afresh, after
which the ovens change their duty, the throttle valve d and damper c of oven A
being shut, and these parts of oven B being opened, by which means the gases will
now circulate in the opposite direction.
Having now described the nature of the said Invention as communicated to
me, and in what manner the same is to be performed, I declare that I claim,-
First. The introduction of steam in both directions into the evacuating tube (b)
of coke ovens of the kind herein referred to, that is to say, in the direction of the
evacuating gases and in the opposite direction, for cooling the tubes for mixing with
the gases and for regulating the progress of the coking process, substantially as
herein before described and represented in Figures 1 and 2.
Second. The introduction of highly superheated steam into the coals at the
bottom of the oven by pipes (g), substantially as herein before described and repre-
sented in Figure 2.
Third. Combining the evacuating tubes with the filling apertures by means
of channels (a), substantially as hereinbefore described and represented in
Figure 2.
Fourth. The construction and arrangement of the condenser kc, and especially the
device for collecting and separately drawing off the more valuable and the less
valuable products of distillation, substantially as hereinbefore described and repre-
sented in Figures 4, 5, and 6.
Fifth. The method hereinbefore described of working alternately, that is to say,
(a) causing the direct suction or evacuation of gases during half the process of
coking only; and (b) using the indirect suction or evacuation of gases of the
adjacent oven (which has progressed in the process of coking) as a regenerating fire
for heating the bottom and the walls of the freshly filled oven, provision being
inade for conducting the gases of the advanced or progressed oven directly into the
chimney, all substantially as hereinbefore described and represented in the accom-
panying Drawings.
In witness whereof, I, the said John Clayton Mewburn have hereunto set
my hand and seal, this Twelfth day of August, One thousand eight
hundred and eighty one