IMPROVEMENTS IN SEPARATING AMMONIA FROM BLAST FURNACE AND OTHER CASES OR VAPOURS AND IN APPARATUS THEREFOR and in what is be performed, to be particularly described and asained in
Year: 1884

page_text: J, GAVIN CHAPMAN of Glasgow in the County of Lanark, Manufacturing
Chemist, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN SEPARATING AMMONIA FROM BLAST FURNACE AND OTHER CASES OR VAPOURS
AND IN APPARATUS THEREFOR and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :—
"
This Invention is a further development of the Invention for which Letters
Patent bearing date the 17th day of December A.D. 1881 N° 5523 were granted
to me.
My present Invention relates First to the separating of ammonia from the gases
and vapours from blast or mineral smelting and other furnaces coking ovens and
other branches of art and manufacture in the gases and vapours proceeding from
which ammonia exists and Second to improvements in apparatus employed for that
purpose.
In carrying out the first part of my said Invention the gases or vapours to be
treated are conducted from the flue leading from the blast or other furnace or oven
into a chamber or vessel which has an inlet connecting it to the flue but has no
outlet. In the said chamber or vessel the gases or vapours are submitted to the
action of sulphuric or other acid having an affinity for ainmonia whereby the
ammonia is separated from the other gases or vapours and combines with the acid
as a solution of ammonia salts.
Figure 1, of the Drawings shews how this part of my said Invention may
conveniently be carried out in practice the flue leading from the blast or other
furnace or oven being marked A, the chamber or vessel marked B, and the passage
connecting the flue and the chamber or vessel marked C. The latter is preferably
made in two halves jointed together at the line b, the joint being preferably luted
with clay or its equivalent.
A number of these chambers or vessels are or may be connected to the flue
throughout its length and as shewn on the Figure each such chamber or vessel is
separate and distinct from all the others and has no outlet or passage away
from it.
To accomplish the combination or absorption of the ammonia with or by the
acid the chambers or vessels may, in accordance with the second part of my said
Invention and as seen in part end elevation and part transverse section at Figure 2,
in part horizontal section and part plan at Figure 3, and in part side elevation and
part longitudinal section at Figure 4, be provided with a horizontal shaft D,

page_text: supported in bearings E, and carrying a series of discs, diaphragms, or plates F, at
short intervals apart, these plates or discs being all preferably tied or stayed
together by bolts a. The shaft D, and bearings E, are preferably made of
gun-metal and the plates F, of copper.
The lower part of each vessel or chamber contains a solution of sulphuric or
other acid which is filled thereinto by the filling hopper H, which may either be at
one side of the chamber as shewn at Figures 3, and 4, or at one end of it as seen
at X, Figure 1, openings as indicated at I, Figures 1, 2, and 4, being made in the
vertical side of the clumber for the passage inwards of the liquid which is filled in
until it rises above the lines I, thereby sealing the said openings and preventing
the outward passage of gas therethrough. The discs or plates F, dip into the acid
solution and the shaft D, is provided with fast and loose pulleys G, G², and by a
belt passed round the fast one G, the shaft D together with the said discs or plates
is rotated (at a speed preferably of about ten to twenty revolutions per minute)
so that all parts of the dics or plates are continuously wetted with acid thereby
exposing a large surface for the separation of the ammonia contained in the gases
or vapours passing into the chamber from the flue A. As the ammonia is absorbed,
fresh quantities of that volatile gas under the well known law of the diffusion of
gases rise from the flue into the chamber B, and are separated as described.
By this meth d of treating the gases namely by causing them to rise from the
main Hue A, into a chamber unprovided with any outlet and consequently not
having a through draft or current much of the heavier impurities contained in the
gases or vapours are deposited in or do not pass from the flue into the chamber as
they do under other modes of treatment and a purer acid solution of ammonia salts
is thus obtained
I consider the herein before described mode of separating ammonia from gases or
vapours in a chamber unprovided with an outlet but connected by an inlet direct
to the gas flue, to be novel in principle, and although the apparatus described may
conveniently be used for carrying the said mode of treatment into practical effect
I do not confine myself thereto as it is obvious that on the same principle many
different forms or arrangements of apparatus may be used.
The improved apparatus herein before described and shewn on the Drawings
besides being used under the mode specified may also be used in the manner set
forth under my said previous Letters Patent, that is to say, a pipe or flue for the
inlet of the gases or vapours may be connected to one end of each chamber as
shewn at M, Figure. 4, and an outlet pipe N, to its other end.
Under the said mode of treatment the gases or vapours may be passed through
one or a series of chambers or vessels the outlet of one being connected to the inlet
of the next when more than one are used.
Under both modes of working water is added from time to time to compensate
for evaporation of the solution caused by the heat of the gases or vapours and in
operating under either of the modes with a series of chambers or vessels the fresh
acid solution is preferably added to the last chamber or vessel of the series and is
thence passed by any suitable pipe or syphon arrangement through succeeding
vessels or chambers becoming more and more saturated in its course until it
reaches the first vessel or chamber, that is to say, the fresh acid solution is employed
where the ammoniacil vapours are weakest
I find it advantageous to have the acid solution in a beated state and if the gases
of themselves do not impart sufficient heat I cause steam to be blown into the
solution in the vessels or chambers.
When the acid solution has become sufficiently saturated the liquor is withdrawn
from the chamber or from the first chamber of the series and it is or may be
treated in any suitable vessels with an excess of alkali, liquid aminonia by
preference. Air and steam are or may then be pumped forced or drawn through
the vessels containing the alkaline liquid in order to oxidize iron and other matters
contained therein and this being effected the liquid is allowed to settle and the
clear supernatent liquor drawn off

page_text: The remaining liquor is or may then be filtered, water being passed through the
filter in order to wash out the salts of ammonia and the combined clear supernatent
and filtered liquor is or may then be boiled down to its salts in the ordinary
manner.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is,
First In separating ammonia from blast furnace and other gases or vapours by
means of sulphuric or other acid, the use of a chamber or vessel having no outlet
but having an inlet connected to the gas flue.
Second The arrangement of apparatus for separating ammonia from blast
furnace or other gases or vapours wherein a series of vertical discs rotating in the
midst of the gases or vapours and moved so as to have their surfaces constantly
wetted by an acid solution are employed substantially as described with reference
to Figures 2, 3, and 4, of the appended Drawings.
Dated this Fifteenth day of April 1884.
GAVIN CHAPMAN,
By Geo. M. Cruikshank, Fel. Inst. P.A.,
135, Buchanan Street, Glasgow,
Agent.