IMPROVED MODES AND MEANS AND APPARATUS FOR ABSTRACTING AMMONIA FROM THE GASEOUS PRODUCTS OF COMBUSTION IN SMELTING AND OTHER FURNACES.”
Year: 1882

page_text: LETTERS PATENT to George Neilson, of Summerlee, in the County of Lanark,
North Britain, Iron Master, for an Invention of "IMPROVED MODES AND
MEANS AND APPARATUS FOR ABSTRACTING AMMONIA FROM THE GASEOUS
PRODUCTS OF COMBUSTION IN SMELTING AND OTHER FURNACES.”
PROVISIONAL SPECIFICATION left by the said George Neilson at the Office
of the Commissioners of Patents on the 28th January 1882.
GEORGE NEILSON of Summerlee in the County of Lanark North Britain Iron
Master "IMPROVED MODES AND MEANS AND APPARATUS FOR ABSTRACTING
AMMONIA FROM THE GASEOUS PRODUCTS OF COMBUSTION IN SMELTING AND
OTHER FURNACES."
This Invention has reference to new or improved modes and means or apparatus
for recovering or abstracting the ammonia from the gases of mineral smelting and
other furnaces, in which coal, shale, coke, or hydro-carbon oils are used as fuel; or in
which such gases are used for heating, lighting, or motive-power purposes, and
which are known to contain ammonia; or from the gases escaping from the
calcining of minerals, or the making of coke, or those from the burning of the
residues of sewerage, or the waste refuse of cities or towns, all before the gases are
allowed to escape to the atmosphere, in a more simple and economical manner than
has heretofore been done.
And the nature and novelty of the Invention consist in abstracting the ammonia
from the said gases while in their hot state, either as they come from their
producing furnaces before being used for heating, lighting, or motive-power
purposes, or it may be after this, but before they are allowed to escape to the
chimney, or to the atmosphere; and by special new or improved means or
construction and arrangement of apparatus for so treating the gases in their hot
state, and abstracting and removing the ammonia therefrom.
One arrangement or combination of the parts of the said apparatus, or appliances
consists of a long horizontal close vessel, preferably rectangular in cross section, and

page_text: made of, or lined inside with lead, or it might be other equivalent material, which
would stand the action of the hot gases, and of the acids used in their treatment.
The hot gases would be led through ordinary pipes, or flues, in at the one end of
the vessel, and out at the other extreme end, jointed fluid tight by flange, faucet,
or other equivalent close joints or branches.
The gases in their hot state, would, or might be, led to this vessel for
treatment, either direct as they were produced from the fuel or materials
being burned, or after they had been burned in other furnaces or vessels for
heating, lighting, or motive-power purposes, as the ammonia still remains in
the residuary gases. This vessel would be formed with transverse openings
all along the top, preferably with short spaces and close tops between them,
for the purpose of inserting deep transverse frames right across the whole
vessel, filled with longitudinal sheets of lead with narrow spaces between them, or
it might be other material which would stand the heat of the gases and the action
of the acids used in their treatment. The area or space between the plates and
the transverse area of the vessel, would require to be greater than that of the pipe
conducting the gases to the vessels, so as to allow a free passage of the gases right
through the vessel between the plates. Each frame carrying the set of plates,
would be formed with a cover for jointing over the transverse openings in the
top of the vessel, through which the frame of plates was inserted, so as to make
all perfectly fluid-pressure tight by screws, glands, or other equivalent, and any
usual jointing material which would stand the heat. And the frames would be
formed-with recesses for retaining the plates at their proper distance apart, and
small studs or other equivalent might be formed at intervals over the surface
of the plates for the like purpose, and to keep them from sagging or bending, and
allow of the free passage of the gases between the plates. Transverse pipes or
ducts would be fitted near the top of the close vessel in the spaces between the
frame of plates (or it might be over the frame of plates) perforated on the sides and
bottom as a "rose," to spray water or dilute acid on to the surface of the plates
to keep them wet, and also fall in a shower down through the gases passing through
the spaces between the plates, and in the space below the rose pipe between the
sets of plates, so as to more effectually absorb the ainmonia from the gases (which
play upon the surfaces of the plates) without condensing or cooling these to any
considerable extent, or below that necessary for their utilization after passing
through the vessel for their after heating or lighting purposes. The absorbing
water or acid liquid would be led into the rose pipes of the vessel through close
jointed branch pipes from one or two main service pipes running along the upper
outside of the vessel, and fitted with regulating taps or valves, and supplied by
gravitation pressure from a cistern above, or from forcing or circulating pumps.
And the frames of plates would not quite extend down to the bottom of the vessel,
but leave a shallow part all along the bottom for receiving the water or liquid
which had absorbed the ammonia from the gas, and which would be drawn off by
branches at the lower part of the vessel, into main drawing off pipes from one or
both ends, in which latter case a division might be formed in the central lower
liquid part of the vessel, to cause the ammonical liquid to flow equally to the
respective discharge branches from which it may be drawn off by gravitation, or by
pumps, or other equivalent, to purifiers or cisterns where the ammonia would be
deposited and removed from the water or acid liquid in the usual manner; this
latter part of the process forming no part of this invention. To prevent the loss
or waste of water, or the diluted acid liquid left in the purifying cisterns, it is
drawn off from these and puinped up to a cistern above, to supply the spray pipes
of the said new or improved close wet plate vessel in a continuous manner, for
abstracting the ammonia from the gases passing through it, all as before described;
or this might be done by continuously circulating pumps, without the use of the
said gravitating cistern.
Although only sets of simple flat plates of lead disposed in a parallel manner,
have been described for the gases acting on their wet surfaces, yet it will be

page_text: understood that they might be made corrugated, and mounted with nearly parallel
narrow spaces between them for the gases to impinge on their surfaces more
effectually, and that they might be made of other sheet-metals enamelled or covered
with glass or porcelain, or other substance which would resist the action of the
heat, or weak acids used.
The acid solution used for abstracting the ammonia from the hot furnace gases
might be used of a density such as would not cause the formation of salts of
ammonia, the liquid might be used in a partially heated state when desired to
prevent undue cooling of the romaining gases when they have afterwards to be
utilised. The rose pipes would also be used for blowing in steam at intervals for
clearing any deposits which may settle about them or the plates.

page_text: .
I
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said George Neilson in the Great Seal Patent Office on the 13th July 1882.
GEORGE NEILSON of Summerlee, in the County of Lanark, North Britain, Iron
Master. "IMPROVED MODES AND MEANS AND APPARATUS FOR ABSTRACTING
AMMONIA FROM THE GASEOUS PRODUCTS OF COMBUSTION IN SMELTING AND
OTHER FURNACES."
My said Invention has reference to a new or improved mode and means or
apparatus for recovering or abstracting the ammonia from the gases or waste
products of combustion of smelting and other furnaces, in which coal, shale, coko,
or hydrocarbons are used as fuel.
The Invention consists in abstracting the ammonia from such gases while in
their hot state, and in new or improved means or arrangements of apparatus for
treating the hot furnace gases to abstract and remove the ammonia therefrom. In
carrying out the Invention the hot furnace gases, either before or aftor utilization
for heating, lighting, or motive-power purposes, are passed through a close vessel
fitted with plates or sheets offering an extended surface against which the gases
|_ impinge and are acted on by dilute acid, or acidulated water, which is caused
to flow over the plates while the gases pass between them.-
In order that my said Invention and the manner of performing the same may be
properly understood, I have hereunto appended a Sheet of explanatory Drawings
representing one modification of my improved apparatus for treating hot furnace
gases for the recovery of the ammonia contained in them. In these Drawings,
Figuro 1 is a vertical section, and Figure 2 is a plan of the improved apparatus,
while Figure 3 is a horizontal section as at the line 1 - 1 in Figure 1, of the box
or casing with the arrangement of plates or sheets, over which the acid or water is
circulated, and through which the hot gases from the furnace are led to be
treated.
The improved apparatus comprises a long rectangular close vessel or casing A,
which in this modification is placed vertically, but which may with nearly equal
advantage be placed horizontally, and which is made of iron or other metal, lined
inside with lead or other material which would withstand the action of the hot
gases and of the acids used in their treatment. To this vessel the hot gases from
the furnace are led through an ordinary pipe or flue, as B, connected to the lower
end of the vessel A, and after traversing the vessel and being heated therein, the
residual gases pass out at the upper end, by a pipe or flue B to the atmosphere.
Within this vessel A are fitted vertically in tiers a large number of plates a, which
in this example are made of porcelain or clay ware, these plates being packed
closely, but with narrow free spaces b between them for the passage of the furnace
gases. The plates are fitted in alternate rows, as shown in the plan Figure 3, with
their ends between each other, to maintain them at regular distances apart; and,
to prevent displacement end wise of any of the plates a, small studs or projections a
are formed on the plates close to their edges. The tiers of plates a which may bo
fitted at right angles to each other are supported by cross bars a² at some height
over the bottom of the vessel to allow the inflowing gases to enter freely below
them, and a free space is left between the upper end of the plates and the cover
of the vessel.
Instead of the slabs or plates of clay ware, sheets of lead or similar material may
be employed, in which case the sheets are carried in transverse supporting frames.
When such frames are employed each frame carrying the set of plates or sheets is
formed with a cover for jointing over transverse openings in the top of the vessel

page_text: through which the frames of plates are inserted. The frames are formed with
recesses for retaining the plates at their proper distance apart, and these plates are
also kept apart by studs or projections or by the thickness of the alternato plates
as shown in Figure 3 to allow the free passage of the gases.
Over openings formed in the cover A¹ of the vessel A are fitted a sories of
pipes C jointed to the cover; and through these pipes C, which are connected by
branch pipes C' to a main pipe C and supply tank C³ above, dilute acid or
acidulated water is caused to flow into the vessel A. The lower ends of the
pipes C are either perforated or fitted as shown with discs c, by means of which
the descending liquid is spread, and falls as spray over the series of plates or
sheets a, and trickles down the surface of the plates to keep them wet, while also
falling in a shower down through the hot furnace gases passing upwards through
the spaces between the plates. The liquid in its descent through the vessel A,
absorbs the ammonia from the hot gases, which play upon the surface of the plates.
The inlet pipes C through which the absorbing liquid is discharged into tho
vessel A, are shown as fitted with taps or valves c¹ by means of which the flow of
liquid through the vessel may be regulated, or this may be done by a valvo or cock
fitted on the main pipe 0%. The acidulated water or diluto acid after passing
through the vessel and in its course absorbing the ammonia of the hot furnace
gases, may be led out of the vessel, and treated in the usual manner for the
recovery of sulphate or other salts of ammonia; but to prevent the loss or waste of
the acidulated water or dilute acid used to absorb the ammonia of the hot gases,
such liquid is caused to circulate through the vessel A continuously or until
saturated. For this purpose the liquid is allowed to flow first into a tank E
below, through a pipe D and trap D' which prevents egress of the gases and ingress
of air. From this tank E the liquid may be pumped up to the cistern C³ above to
supply the spray pipes C, discharging into the vessel A and cause a continuous
circulation of the liquid through the vessei A. for abstracting the ammonia from
the gases passing through it. Instead of using pumps, the liquid in the cistern is
discharged at intervals through a pipe e, fitted with a stop valve e', into a close
cistern F, and from this cistern or vessel F the liquid is forced up through a
pipe G to a tank C³ above by means of air pressing on the surface of the liquid in
the vessel F, the air being supplied under pressure from an air compresser or
blower, and entering by a pipe f
The acid solution used for abstracting the ammonia from the hot furnace gases
may be of a density such as would not cause the formation of salts of ammonia
in the vessel or cisterns, and the liquid might be used in a partially heated stato
when desired to prevent undue cooling of the remaining gases when they have
afterwards to be utilised.
A steam pipe H is fitted in connection with the vessel A to blow in steam
either continuously or at intervals, partly to assist in cleaning the surfaces of the
plates a, or to prevent the deposit of tarry matters, and partly to maintain a
supply of liquid for absorbing the ammonia as the acid in the liquid becomes
partially neutralised.
Having thus described my said Invention, and the manner of performing the
same, I have to state that I do not restrict myself to the precise details of the
apparatus herein described or delineated, but what I consider to be novel and
original and therefore claim as the Invention secured to me by the herein before
in part recited Letters Patent is,―
First. The treating of hot furnace gases for the abstraction or recovery of the
ammonia contained therein by passing acidulated liquor through the gases, in the
manner herein set forth, and by means of apparatus substantially such as herein
described.
Second. The construction and arrangement or combination of the parts of
apparatus for effecting the abstraction or recovery of the ammonia contained in
furnace gases, substantially as herein described and delineated,
Third. In apparatus for effecting the abstraction or recovery of ammonia from

page_text: furnace gases, the arranging and combining of a series of sheets or plates within a
close vessel through which the furnace gases are led, while dilute acid or
acidulated water is discharged over the surfaces of the plates and through the
vessel, substantially as herein set forth.
In witness whereof, I, the said George Neilson, have hereunto set my hand 5
and seal this Twelfth day of July, in the year of our Lord, One thousand
eight hundred and eighty-two.
Witness:
WALLACE FAIRWEATHER C.E.
Of W. R. M. Thomson & Co.
Patent Agents,
Glasgow.
GEO. NEILSON. (L.S.)