Year: 1886

page_text: Date of Application, 24th June, 1886
Complete Left, 24th Mar., 1887.
Complete Accepted, 24th Sept., 1887.
JOHN HAMMOND of Lewes in the County of Sussex Gas Engineer do hereby
declare the nature of my said invention to be as follows:-
:
The objects of my invention are, to effect the complete purification of coal gas by
means of concentrated liquid ammonia to recover the sulphur and ammonia for the
purpose of manufacturing therefrom sulphuric acid, and sulphate of ammonia and to
manufacture and apply improved apparatus for effecting the same.
:
My invention consists of further improvements in a certain former invention, for
which I have obtained Letters Patent, No. 381777 and 237678.
In carrying out that part of my invention which relates to the purification of coal
gas, I effect the same as follows:-
In the original Letters Patent above mentioned one part of the said Invention con-
sisted of "introducing to the hydraulic main of the Gas Works strong gaseous ammonia
and the alkaline vapour mixing freely with the hot crude coal gas would slowly
absorb therefrom its equivalent of acid impurity and be eventually condensed in the
form of strong combined ammoniacal liquor, from which the ammonia could be easily
recovered by suitable treatment, to form sulphate of ammonia, or prepared for further
utilization, as a purifying agent, and thus used over and over again to purify the
coal gas, leaving only surplus ammonia to be converted into sulphate. It is obvious
that the above Patents combine, the purifying of the coal gas simultaneously with the
manufacture of Sulphate of Ammonia." I now supplement the above processes by
introducing repeated additions of strong liquid ammonia into specially constructed
apparatus hereinafter described, at the outlet of hydraulic main, the strong liquid
ammonia, being easily vapourized and mixing freely with the crude gas; both together
are suddenly subjected to alternate heat and cold, whereby the alkaline vapours suddenly
combine with crude coal gas and precipitate therefrom much of its acid impurity.
The Coal Gas leaving this apparatus in a heated condition passes through a special
chamber in which the benzole vapours are being distilled from the light oily tar
from condenser, and thus any slight loss of hydro-carbon vapours, occurring in the
previous apparatus, is quickly restored, and the illuminating power of the gas
maintained, or increased as desired. The coal gas now flowing freely forward,

page_text: through the ordinary mains and condensers, enters the Washer and tower scrubbers,
in which it is again treated to fresh supplies of caustic ammonia, the ammonia being
at last trapped, and recovered by means of distilled water, the tower scrubbers in
which the coal gas is treated to the caustic ammonia and in which also the ammonia
is recovered by means of distilled water, are to be filled with a
consisting of a combination of iron and hard gas coke, prepared in such a manner as
special material,
to fix the iron in a finely divided condition in the Coke. A measured quantity of
atmospheric air having been admitted to the hot coal gas at a point (by preference
before the coal gas enters the aforesaid benzole chamber) and mixing freely with the acid
alkaline and coal gases, in the combined coke and iron scrubbers produces of necessity
strong chemical action upon the impurities in the coal gas and the flowing liquid
greatly helps to their subsequent removal. It is desired by this method to precipitate
the Sulphuretted hydrogen from the Coal Gas in the form of free sulphur.
This Invention also consists in further improvements in apparatus for the produc-
tion of crude caustic ammonia and also the concentrated volatile liquid ammonia, by
means of a modified arrangement of the gas liquor purifying tower as set forth
and described in my former Letters Patent No. 2376, 1878. Many of the parts
being now made of lead combined with cast iron and jointed by means of the best
rubber, to prevent as much as possible loss of ammonia from the contact of the
hot caustic liquor with Iron, (and more especially wrought Iron), thereby forming
Cyanogen compounds and as certain definite and regular temperatures are necessary
to the successful working of the different chambers in the said gas liquor towers, it is
now arranged that one part shall be heated by means of hot water or liquid circulating
through pipes or coils: Another chamber is heated by steam, exhaust, or high
pressure, passing through pipes or coils as before described in my Letters Patent 2376-
1878. Again caustic ammonia liquid flowing into another chamber or vessel is
submitted to treatment with free high pressure steam and caustic milk of lime and
the gaseous ammonia thus liberated can be concentrated in suitable lead condensers,
and used for the purpose of purifying coal gas as hereinbefore described; the residual
lime and liquid containing Cyanide of Calcium can if desired be treated for the recovery
of the Cyanogen compounds. The arrangement of the different parts of the above
apparatus may be in duplicate to provide that the vapours escaping from one part may
be passed through the liquid contained in the other, and vice versa, as in principle
described in Letters Patent No. 3817-1877 and No. 2376-1878. Pipes and valves
are also arranged from all of the above mentioned chambers to carry the foul gases
and surplus ammonia to the acid saturaters to assist in forming sulphate of ammonia
simultaneously with the production of ammonia for the purpose of purification of coal
gas; the foul gases from the saturaters may be treated as described in my said
former specification.
The specially constructed apparatus at the outlet of hydraulic main consists of a
series of small chambers or vessels, fitted with small tubes, and surrounded by steam
or heated air, to first raise the temperature of the passing coal gas, and to introduce
thereto strong liquid ammonia, and this quickly vapourizing and mixing freely with
the coal gas, passes through similar chambers or vessels surrounded by cold water or
air, (lowered in temperature by any suitable means); these said refrigerating chambers
being placed between the hot chambers, the temperature of the passing gas is thereby
suddenly lowered, and thus by suddenly and alternately raising and lowering the
temperature of the gas, it is expanded and contracted, and the alkaline vapours
suddenly combine with the acid impurity of the coal gas, and are precipitated in the
form of strong combined liquid ammonia, which can be readily dealt with as before
described; the number and size of chambers or vessels to be regulated according to
the quantity of passing gas to be dealt with, and the effect desired to be produced.
Dated 9th T
1000

page_text: Purification of Coal Gas by Concentrated Liquid Ammonia, and
the Recovery of Sulphur and Ammonia for the Manufacture of
Sulphuric Acid and Sulphate of Ammonia.
I JOHN HAMMOND of Lewes in the County of Sussex, Gas Engineer, do hereby
declare the nature of the said invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
My invention consists of further improvements in certain former inventions for
which I have obtained Letters Patent No. 38177 and 237678.
In carrying out that part of my invention which relatos to the purification of Coal
Gas, I effect the same as follows:-
In the original Patents, above mentioned, one part of the said invention consisted
in introducing to the hydraulic nain of the Gas works, strong gaseous ammonia, the
alkaline vapour mixing freely with the hot crude gas, would slowly absorb therefrom
its equivalent of acid impurity and be eventually condensed, in the form of strong
combined ammonical liquor, the ammonia could be easily recovered by suitable
treatment, to form sulphate of ammonia, or prepared for further utilization, as a
purifying agent, by passing through the Gas liquor purifying towers (as described in
iny Letters Patent No. 237678, Fig. 1) and thus used over and over again. to purify
Coal Gas, leaving only surplus ammonia to be converted into Sulphate of Ammonia.
It is obvious that the above Patents combine the purification of Coal Gas
simultaneously with the manufacture of Sulphate of Ammonia.
I now supplement the above processes, by introducing repeated additions of strong
liquid Ammonia into a series of small chambers or vessels connected with the outlet
pipes of hydraulic mains, the said chambers or vessels, being fitted with small tubes
for the purpose of raising the temperature of the passing Coal Gas, by means of steam,
superheated or otherwise similar chambers are also provided, the temperature of
which can be regulated by liquid brine, with special Ammonia, refrigerating plant, or
other suitable means; the said refrigerating chambers being placed between the
aforesaid hot chambers, subjects the passing Coal Gas alternately to heat and extreme
cold, thereby assisting the alkaline vapours in the precipitation of the acid impurity
from the Coal Gas; the strong combined liquid Ammonia thus produced can be readily
dealt with as before described; the number and size of chambers or vessels to be
regulated according to the quantity of the passing Gas to be dealt with, and the effect
desired to be produced. The Coal Gas leaving this apparatus in a heated condition
passes through a special chamber in which the benzole vapours are being distilled,
from the light oily tar from the condensers; and thus any slight loss of hydro-carbon
vapours, occurring in the previous apparatus, is quickly restored, and the illuminating
power of the Gas maintained or increased, as desired.

page_text: The Coal Gas now flowing freely forward, through the ordinary mains and
condensers enters the Washers and tower Scrubbers, in which it is again treated to
fresh supplies of Caustic Ammonia; the Ammonia being at last trapped and recovered
by means of distilled water. The scrubbers or other suitable vessels, in which the
Coal Gas is treated to the liquid Ammonia, being now filled with a special material
consisting of a combination of iron and hard Gas Coke, prepared by steeping hard
Coke in a strong solution of per-chloride of iron, and afterwards fixing the iron by
heating the Coke to redness in a hot retort; or the Coke may be steeped in a strong
solution of sulphate of iron and afterwards oxidised by exposure to the air. A
measured quantity of atmospheric air having been admitted to the hot Goal Gas at a
point, say into or near the benzole chamber or Still,-produces of necessity strong
chemical action upon the impurities of the Coal Gas while passing through the
combined coke and iron scrubbers, precipitating much of the sulphuretted hydrogen in
the form of free sulphur, the flowing alkaline liquids assisting to the subsequent
removal of other impurities.
This invention also consists in further improvements in apparatus for the production
of Crude Caustic Ammonia, and also the concentrated volatile liquid Ammonia, by
means of a modified arrangement of the Gas liquor purifying Towers, as set forth and
described in my former Letters Patent No., 2376, 1878.
Many of the parts being now made of lead combined with cast iron (and jointed by
means of the best rubber) to prevent loss of Ammonia from the contact of the caustic
liquor with iron, (and more especially wrought iron) and, as certain definite and
regular temperatures are necessary to the successful working of different chambers in
the said Gas liquor towers, it is now arranged that one part shall be heated by means
of hot water or liquid, circulating through pipes or coils; another chaniber is heated
by exhaust or high pressure steam by means of pipes or coils as described in my said
letters Patent 2376, 1878.
Again, Caustic Ammonia liquor flowing into another chamber or vessel is submitted
to treatment with free high pressure steam and caustic milk of lime, and the gaseous
Ammonia thus liberated can be concentrated in suitable lead condensers, and used for
the purpose of purifying Coal Gas as herein before described; the residual lime and
liquid containing calcium cyanide can if desired be treated for the recovery of the
cyanogen compounds.
The arrangement of the different parts of the above apparatus may be in duplicate
so as to provide that the vapours escaping from one part, may be passed through the
liquid contained in the other, and vice versâ, as in principle described in my Letters
Patent No. 3817,-1877, and No. 2376,-1878.
Pipes and valves are also arranged from all of the above mentioned chambers, to
carry the foul gases and surplus ammonia to the acid saturators, to assist in forming
Sulphate of Ammonia, simultaneously with the purification of Coal Gas by the above
method.
And in order that my
said invention may be particularly described and ascertained,
reference is hereby made to the accompanying drawings, in which Fig. 1 is a general
sectional elevation of the apparatus, and Fig. 2 is an enlarged sectional view, shewing
the method of constructing the tube chambers in the towers 14 and 15 and connecting
the tubes with the tube plates.
Referring to Fig. 1, the pump 32 draws ordinary gas liquor from the well 35
through the pipe 34, fitted with a cock 33; or, if desired, it pumps strong combined
liquid ammonia from the coal gas scrubber 2, through the cock 37; the scrubber 2
being fitted with an automatic overflow pipe 36. The entry of gas to the scrubber 2
is by no means of the pipe 1.
The pump delivers the ammonia liquors by the pipe 40 to the chamber 41 at the
base of the ammonia liquor regenerating towers.
The pump drives the cold ammonia liquors up through the tubes into the chamber 42;
from thence down through the tube 43 to the space surrounding the tubes at the base
of the tower 14. Here the liquor becomes slightly heated by means of the caustic
ammonia, herein after described.

page_text: Passing from the last mentioned chamber by the pipe 73 to the chamber 74, the
ammonia liquors are further driven through the tubes in the upper part of the
tower 15, and rise to the height of the overflow pipe 51, down which it proceeds to
the chamber 79. The liquors rise from the chamber 79 to the overflow pipe 77; but,
while passing through the tubes, heat is communicated by means of the high pressure
steam (superheated or otherwise) surrounding the tubes. By these
combined gases are disengaged from the hot liquors. These combined gases pass, by
the pipe 78 into the chamber 15, for concentrating and agitating the ammonia liquor,
and setting free combined sulphur gases, which pass, by means of the pipe 71, to the
acid saturator 31, thereby forining a given quantity of sulphate of ammonia.
means the
From the tower 14 the now caustic ammonia liquor passes, by pipe 77, to the space
surrounding the upper set of tubes in the tower 15, communicating, in its passage,
some of its heat to the cooler ammonia liquors ascending through the tubes from the
pump 32. The liquor then passes out by the tube 76 to the chamber 45, and, through
the tubes, to the chamber 44, from whence it rises again, through the pipe 75, to the
space surrounding the tubes, in the lower compartment of the tower 15; the
temperature being now reduced to that of the liquors entering the base of the tower.
The cold caustic ammonia may now be passed through the pipe 52 to the pipe 3,
communicating with the ordinary coal gas scrubber 2, and also (when the cock 4 is
opened) with the large scrubber purifier 5, containing combined iron and coke. 6 is
the distributor for the ammonia, leading to a series of perforated pipes similar to those
marked 7, 7.
It should be observed that the coal gas, entering the top of the scrubber 2, passes
down through the scrubber with the liquid ammonia; but, in the scrubber 5, the coal.
gas rises up through the purifying material, meeting fresh liquid ammonia in its
passage; excess of ammonia being trapped in an ordinary clean water scrubber (not
shewn in the drawing). The gas enters by the pipe 68, and leaves the purifier by the
pipe 69.
When desired, the surplus ammonia liquor may be drawn off by the cock 21,. in the
lower portion of the tower 14, through the pipe 22, by means of the injector 20; a
supply of superheated steam being obtained from the pipe 12 regulated by the cock 19.
By this means the liquor is atomised, or divided into spray, and the ammoniacal and
other gases are set free, and pass away by means of the pipe 83 to the saturator 82;
for the manufacture of sulphate of ammonia.
•
The liquors descending upon the shelves in the gas liquor still 38, overflow, by
means of the pipe 39, into the lime still 72, cream of lime being supplied from the
mixing tank 48, through the cock 49, to the funnel 50, and descends by the pipe 46
to the lime still 72. 66 and 67 are pipes for drawing off refuse liquor and lime mud
at different heights to the receptacle 65, which receptacle is fitted with an overflow
pipe 81.
The injector 18, at the base of the gas liquor still 38, is for the purpose of drawing
heated air from the steam superheater furnace 10, when the cock 17 is opened. 16 is.
the regulating valve for steam to the injector. The heated gases thus driven into 38
raise the temperature of the still and assist in the decomposition of the fixed ammonia.
By means of the pipe 23 the injector 18 also draws the surplus acid gases from the
chambers 24 and 25 for burning sulphur gases or precipitating sulphur. The supply
of sulphur gases, arising from the acid catch tower 30, flows, by means of the pipe 29,
through the cock 85, to the coal gas Bunsen burner 56; sulphur gases being ignited
by the burner produce sulphurous acid, which flows from chamber 25 to 24, by means
of the pipe 27. A regulated quantity of sulphuretted hydrogen passes through the
cock 28 to the tower 24 (when the cock 26 is shut) and, mixing with sulphurous acid
in the chamber 24, precipitates a given quantity of free sulphur, the formation of
objectionable acids being prevented by the addition of chloride of calcium or chloride
of magnesium through the tower 24.
When it is desired to produce concentrated caustic ammonia, strong liquid ammonia
may be drawn from the tower 15 through the cock 47, with the cock 84 open or shut,
as desired, the liquors flowing through the pipe 46, to the lime still 72, and, being

page_text: treated with lime as herein before described, and agitated by superheated high pressure
steam, conveyed by the pipe 8, and regulated by the cock 11, through the steam
blower 9. The strong ammonia vapour now ascending by the pipe 55 is concentrated
in the series of chambers 53, the strong ammonia vapour passing away through the
pipe 60 to the hydraulic and gas mains 63 and 64. An additional pipe 61 supplies
gaseous ammonia to the cold gas immediately before entering chamber 59. The
chamber 59 is heated by hot air, hot furnace gases, or superheated steam, for raising
the temperature of the passing coal gas, in the space surrounding the tubes. 62 is a
pipe conveying caustic liquid ammonia to the coal gas, in its passage from the chamber
59 to 58. 58 is a chamber fitted with tubes, through which cold water or brine, from
any suitable refrigerating plant, may be caused to flow. This condenses the hot coal
gas combined with the ammonia vapours, and precipitates therefrom much of its
impurities; provision being made, between chambers 57 and 58, for the overflow of
condensed liquors to the ordinary tar and liquor well. Coal gas passing to 57 is again
heated by similar means to those described with respect to 59, and making its exit by
pipe 80 passes on to the benzole chamber, fully described in patent No. 14,395**.
54 is a pipe conveying weak ammonia water to the lime still 72.
70 is a steam boiler which supplies the requisite heat, by means of the pipe 8,
leading to the coil in the superheater 10. This superheater is fitted with a furnace or
other source of heat to raise the temperature and superheat the steam, on its passage
to the steam blower 9, the pipe being fitted with the cock 11.
In the enlarged section (Fig. 2) the method of construction of the tube chambers in
the towers 14 and 15 are shewn, india rubber rings being fitted round the tubes and
between flanges. The inside of the cylinder and cylinder cover may be lined with
lead.
I wish it to be understood that I do not restrict myself to the precise details herein-
before described, as they may be modified without departure from the essential
features of my invention.
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 The use of a series of chambers in the manner and for the purpose
described, whereby the passing Gas can be made alternately hot and cold in the
presence of free ammonia and vapour, for the purpose of suddenly condensing
therefrom much of its impurity, which may then be carried off by the strong
condensed alkaline liquors, substantially as herein before described and shewn on the
drawings.
Secondly The preparation and use of Coke and Iron as and for the purpose
described, with the admission of a regulated quantity of air (carburetted as described
or otherwise) to keep the same chemically active upon the passing gas, in the presence
of liquid ammonia or water, substantially as herein before described and shewn on
the drawings.