An Improved Method or Process of Treating Substances Containing Nitrogen for the Manufacture of Ammonia.
Year: 1896

page_text: Date of Application, 9th Dec., 1896-Accepted, 6th Mar., 1897
[Communicated from abroad by CARL PIEPER, of 3 Hindersinstrasse, Berlin, in
the Empire of Germany, Engineer.]
An Improved Method or Process of Treating Substances Containing
Nitrogen for the Manufacture of Ammonia.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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:-
It is well known that, for the production of ammonia, substances containing
nitrogen have been heretofore treated by a fractional method, as follows: that is
to say, after the raw material has been freed from moisture, it is subjected to a
distillation process whereby the gasifiable and tarry substances are removed;
a portion of the nitrogen is extracted in the course of this operation, and the
residual product is coke, still containing some nitrogen. The next stage of the
process consists in treating this nitrogenous coke with superheated steam-in a
chamber or vessel from which air is excluded-so as to set free the nitrogen from
the coke, i.e. from the carbon and nitrogen compound, which nitrogen combines with.
the hydrogen of the steam, to form ammonia. From the remaining products of
decomposition water-gas is obtained.
When the substances containing nitrogen are thus treated in a single chamber or
vessel say, a retort-a partial advantage only is taken of the raw material, while
the treatment of bye-products is incomplete. By my invention I have developed
the aforesaid process and rendered its performance continuous, my object being to
utilise, both, the product of the desiccation process-mainly steam-and the
products of the "steaming" operation (as the separation of the nitrogen from the
carbon is generally termed), in a series of chambers or receivers; so that, from
stage to stage, the products may become more and more enriched.
In carrying out the aforesaid continuous process, the principle of counter-currents
may, with special advantage, be applied to a practical purpose.
Instead of one retort I use several, for example six, and in performing my
improved process, I place the six vessels in communication with each other
by means of suitable pipes and chaunels, fitted with devices for closing them; the
whole being so arranged as to comply with the requirements of the process.
Suppose, now, that at a predetermined period of the operation of all the retorts,
the following condition has been reached viz. one of the retorts-the sixth-is
completely cut off from the rest, so that it may be discharged of its contents and
re-filled; and that the first retort, just refilled, is in the drying stage, wherein the
raw material is deprived of whatever amount of moisture it naturally contains,
while in the second retort, let us say, this stage of desiccation (the temperatures
occurring in which should but slightly exceed 100° Centigrade) has just been
completed, and the temperature therein has been raised to 300° Centigrade or
upwards, and the process of distillation has commenced; while in the third, fourth
and fifth retorts the distillation has been completed, or in other words the tarry
and gasifiable products having been separated from the raw material, the remaining
nitrogenous coke is being acted upon by superheated steam. Six retorts are ample

page_text: for carrying the improved process to its full development, because the drying
operation, in the first place, and the distilling process next, require far less time for
their completion, than the "steaming process" so-called.
According to my invention the steam, generated in the drying operation which
takes place in the first retort, is conducted through a superheater; and then,
from such superheater, is distributed to retorts Nos. 5, 4 and 3 (the order of
succession being as here indicated). Or the superheated steam, in the first
instance is allowed to flow from the 1st retort into the 3rd, there to mix
with the products of decomposition which have formed in that retort in the
meantime; and then to pass on from the 3rd to the 4th, and from the 4th, into
the 5th retort.
This last-mentioned course is especially valuable for the reason that, as I first
introduce the hottest steam into the third retort, this retort-by the action of such
steam as an internal heating medium,-may very quickly be raised to a controllable
temperature of over 500° Centigrade, which is required for the steaming process;
while at the same time, in the 4th and 5th retort, the temperature requisite for
proper steaming has had an opportunity of becoming developed by the external
heating action, exercised from all sides.
In the first or "parallel connection" method, the counter-current principle is the
most serviceable, because the hottest steam, discharged from the superheater, enters
that retort first, which at the time happens to be in the last stage of the steaming
process.
In the second or "series connection" method this counter-current principle is
not applied until the third retort has been raised, by the superheated steam,
to the temperature required for the steaming operation; while before such
temperature is attained the direct steam supply to the third retort commences, and
the connection is made between the 3rd and 4th retorts, and also the direct
connection between the 4th and 5th retorts. After this time however a "parallel.
connection" is made.
It will readily be seen that the products of the second retort, which-as assumed
above is engaged in the distilling operation, must not be allowed to mix with the
products of the 1st, 3rd, 5th and 6th retorts; for the reason that the treatment of
these products, as compared to the products of the 3rd, 4th and 5th retorts,
necessitates the adoption of a complicated process, whereby only about one third of
the nitrogen contained in the raw material can eventually be gained. Whereas
the remaining two-thirds of the nitrogen, contained in the raw material,
may be obtained from the 3rd, 4th and 5th retorts mixed with carbonic
oxide and hydrogen; so that two thirds of the nitrogen is separated in
the form of ammonia without the necessity for any complicated purifying
operation while at the same time a gas of high combustible value is obtained as
a bye-product.
What, consequently, differentiates the novel method of operation from all those
which have hitherto been applied to the same purpose, is that-as hereiuabove set
forth it enables two-thirds of the main product of the process to be obtained. direct,
and in a pure condition; the remaining one third alone requiring special treatment;
whereas by all methods heretofore known, the whole of the product of distillation
and decomposition is required to be subjected to a complicated and expensive purifying
operation.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
(1.) For the preparation of ammonia from substances containing nitrogen
the herein described continuous process wherein the steam, generated during
the drying stage in one retort, is utilized in a number of retorts to assist the
progress of the steaming operation, the products of such operation being included
in the case of successive working, the object of the process-applicable in.

page_text: accordance with the counter-current principle-being to enrich the said products,.
whilst the products of distillation are treated separately.
(2.) In the said process the employment of a series of retorts say, six-so
connected together, that the products of the first retort may be transferred to
the 5th, 4th and 3rd retorts; or so that, after closing the access to the 5th
and 4th retorts, the product of the first retort may be conducted first into the
3rd retort; then, from the third retort, through a direct connection, into the
4th retort; and next from the 4th into the 5th retort, likewise through a direct
connection; for the purpose of connecting the retorts either in "parallel" and at
the same time utilizing the steam, or in "series," in which case the third retort may,
by internal heating with steam, be, controllably, raised to the temperature requisite.
for steaming, substantially as described.
Dated this 9th day of December 1896
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant...