IMPROVEMENTS. IN THE PURIFICATION OF GAS AND GAS LIQUOR
Year: 1874

page_text: LETTERS PATENT to Frank Clarke Hills, of the Chemical Works,
Deptford, in the County of Kent, Manufacturing Chemist, for the
Invention of "IMPROVEMENTS. IN THE PURIFICATION OF GAS AND GAS
LIQUOR."
PROVISIONAL SPECIFICATION left by the said Frank Clarke Hills at.
the Office of the Commissioners of Patents, with his Petition, on
the 14th March 1874.
1
.
I, FRANK CLARKE HILLS, of the Chemical Works, Deptford, in the
County of Kent, Manufacturing Chemist, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN THE PURIFICATION OF GAS AND
GAS LIQUOR," to be as follows:- -
My Invention relates to a process described in the Specification of
Letters Patent granted to me and bearing date 25th April, A.D. 1868,
No. 1369, by which process gas liquor was to a certain extent freed from
sulphuretted hydrogen, carbonic acid, and other impurities, and "when"
thus purified was used for purifying gas. According to that process the

page_text: gas liquor was boiled in one of a series of stills, and the ammoniacal
vapour thus driven off was passed through the other stills into which
cold crude gas liquor was run, which liquor took up the ammonia, and
the ammoniacal liquor thus obtained was used in scrubbers for the
purification of gas.
My present Invention consists of the improvements herein-after
described principally in purifying gas liquor, and in using the gas liquor
so purified, or some of its products, in the purification of gas.
"
In purifying and using gas liquor according to my Invention I
proceed as follows:-I substitute for the series of stills herçin-before
referred to a single still or vessel connected by a pipe to a scrubber
which is kept pretty hot, and through which the crude gas liquor to be
purified is run on its way to the said still or vessel, in which instead of
boiling such gas liquor as described in the Specification of my said
Patent, No. 1369, A.D. 1868, I merely heat it to a temperature of about
180°, and keep it at that temperature for a certain time so as to drive off
the greater part of the carbonic acid and sulphurctted hydrogen which
such liquor contained, together with some ammonia. These products
pass from the still to the scrubber, which they enter at the lower part in
the usual way, and then pass up through the coke or other medium
through which the crude gas liquor is run on its way to the still, as
aforesaid, which gas liquor as it meets the ascending gases condenses
the greater part of the ammonia which runs back into the said still with
the said gas liquor, while the sulphuretted hydrogen and carbonic acid
gases escape at the upper part of the scrubber with a little ammonia,
which latter may be taken up by water (preferably warm) in a scrubber
or washer, or by acid, or other suitable agent.
“Instead of running the hot gas liquor to be purified through the
scrubber into the still, as herein-before described, it may be run in a³
regulated stream direct into the said still on to the surface of the hot
purified gas liquor. In this case most of the gases contained in the
fresh liquor will be driven off, but with more ammonia, than if the liquor
were run through the scrubber before entering the still. The gases,
driven off are then passed through a scrubber or condenser, or through-
acids or other agents, to prevent the ammonia from escaping with such
gases.

page_text: The still may be heated by steam or by fire, and it may be furnished
with diaphragms, as described in my said Specification, No. 1369, A.D.
1868, with reference to the boiler "E," so that the crude gas liquor may
be run in at one end of the said still and through the several compart-
ments thereof to the other end, whence the said gas liquor runs out
purified.
The gas liquor to be purified is run into the still in a regulated stream
and flows out purified, as aforesaid, and the hot purified gas liquor is
made to heat the cold gas liquor in any convenient way, but preferably
by means of a heater constructed like the heater "B" described in my
said. Specification, and the gas liquor so heated is run into the upper
part of the scrubber through which the gases driven off pass to condenso
and combine with the ammonia carried over with the said gases. The
carbonic acid and sulphuretted hydrogen may be passed through oxido
of iron, by which means the sulphur of the sulphuretted hydrogen may
be retained, the carbonic acid escaping to the chimney through a
pipe.
The crude gas liquor after being licated by the hot purified gas liquor
as herein-before described, may be kept in a vessel for some time at a
temperature of about 160° to 170° before passing through the scrubber
on its way to the still, and will at this heat give off a good deal
of sulphuretted hydrogen, which may be utilized for making sulphide of
lime or sulphide of ammonia to purify gas from the more fixed sulphur
compounds.
Instead of heating the crude gas liquor as aforesaid in the scrubber by
the hot purified gas liquor which runs out of the heater or still the said
crude gas liquor may be run cold or lukewarm into the scrubber. through
which the gases are escaping from the said still, and from thence into
the said still, but in this case it will take more heat to drive off the gases.
which will in a greater or less degree combine with the cool liquor and
be taken again into the still, but there will be no escape of ammonia
with the gases passing out of the scrubber as it will be taken up by the
cool gas liquor.
If the hot purified gas liquor from the still is not used to heat the
cold gas liquor the said hot liquor should be run into the gas condenser
near the hydraulic main so that such liquor may there be cooled with,
the ordinary gas liquor which is there condensed, and the combined.
liquors may then be used to purify the gas in the gas scrubbers. Or.

page_text: cold purified gas liquor may be run into the condenser and used as above
described.
The ordinary gas liquor may be made to combine with more of the
carbonic acid combined with the gas, and so to free the said gas from
such acid if the said gas be passed direct from the hydraulic main at a
temperature of about 160° into a scrubber. Hot water should in this
case be run through the said scrubber so as to keep it at the above
temperature.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frank Clarke Hills in the Great Seal Patent Office
on the 11th September 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANK
CLARKE HILLS, of the Chemical Works, Deptford, in the County of
Kent, Manufacturing Chemist, send greeting.
•
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of March, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Frank Clarke Hills, Her special
license that I, the said Frank Clarke Hills, my executors, administrators,
and assigns, or such others as I, the said Frank Clarke Hills, my
executors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE PURIFICATION OF GAS AND GAS LIQUOR," upon the condition (amongst
others) that I, the said Frank Clarke Hills, my executors or admini-
strators, by an instrument in writing under my, or their, or one:
of their hands and seals, should particularly describe and ascertain

page_text: the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Frank Clarke Hills, 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 thereof, that is to say :—
My Invention relates to a process described in the Specification of
Letters Patent granted to me and bearing date 25th April, A.D. 1868,
No. 1369, by which process gas liquor was to a certain extent freed from
sulphuretted hydrogen, carbonic acid, and other impurities, and when
thus purified was used for purifying gas. According to that process the
gas liquor was boiled in one of a scries of stills, and the ammoniacal
vapour thus driven off was passed through the other stills, into which
cold crude gas liquor was run, which 'liquor took up the ammonia, and
the ammoniacal liquor thus obtained was used in scrubbers for the
purification of gas.
•
My present Invention consists of the improvements herein-after
described principally in purifying gas liquor for the purification of gas.
· I proceed as follows:-I substitute for the series of stills herein-before
referred to a single still or vessel connected by a pipe to a scrubber
through which the crude gas liquor to be purified is run on its way to
the said still or vessel, in which instead of boiling such gas liquor, as
described in the Specification of my said Patent, No. 1369, A.D. 1868,
I merely heat it to a temperature of about 180°, and cause it to pass
through the still at such a rate as to drive off the greater part of the
carbonic acid and sulphuretted hydrogen which such liquor contained;
together with some ammonia. These products pass from the still to the
scrubber, which they enter at the lower part in the usual way and then
pass up through the coke or other medium through which the crude gas
liquor is run on 'its way to the still, as aforesaid, which gas liquor as it
meets the ascending gases condenses the greater part of the ammonia
which runs back into the said still with the said gas liquor, while the
sulphuretted hydrogen and carbonic acid gases escape at the upper part
of the scrubber with a little ammonia, which latter may be taken up by.

page_text: 'water, preferably warm, in a scrubber or washer, or by acid, or other
suitable agent.
Instead of running the hot gas liquor to be purified through the
scrubber into the still, as herein-before described, it may be run in a
regulated stream direct into the said still on to the surface of the hot
purified gas liquor. In this case most of the gases contained in the fresh
liquor will be driven off, but with more ammonia than if the liquor
were run through the scrubber before entering the still. The gases
driven off are then passed through a scrubber or condenser, or through
acids, or other agents to prevent the ammonia from escaping with such
gases.
i
The still may be heated by steam or by fire, and it may be furnished
with diaphragms, as described in my said Specification, No. 1369, A.D.
1868, with reference to the boiler E, so that the crude gas liquor may be
run in at one end of the said still and through the several compartments
thereof to the other end, whence the said gas liquor runs out purified.
The gas liquor to be purified is run into the still 'in a regulated stream,
and flows out purified, as aforesaid; and the hot purified gas liquor is
made to heat the cold gas liquor in any convenient way, but preferably
by means of a heater constructed like the "heater B," described in my
said Specification, and the gas liquor so. heated is run into the upper part
of the scrubber through which the gases driven off pass to condense and
combine with the ammonia carried over with the said gases. The carbonic
acid and sulphuretted hydrogen may be passed through oxide of iron,
by which means the sulphur of the sulphuretted hydrogen may be
retained, the carbonic acid escaping to the chimney through a pipe.
The crude gas liquor after being heated by the hot purified gas liquor,.
as hercin-before described, may be passed at a temperature of about from
160° to 170° into an intermediate tank or vessel on its way to the still to
be purified, or be raised in such vessel to such temperature and be
passed through such vessel at such a rate as to allow it time to give off
sulphuretted hydrogen, which may be utilized for making sulphide of
lime to purify gas from the more fixed sulphur compounds.
Instead of heating the crude gas liquor as aforesaid on its way to the
scrubber by the hot purified gas liquor which runs out of the heater or
still the said crude gas liquor may be run cold or lukewarm from the
reservoir into the scrubber through which the gases are escaping from

page_text: to a pipe c, the opposite arms of which have perforations at opposite
sides, so that as the said liquor issues from the said perforations it causes
the said pipe and funnel which are mounted on a spindle c³ to revolve
after the manner of a Barker's mill and thus to distribute the said
liquor, which descending through the scrubber passes by the pipe c¹ to
the still D, which is kept at a temperature of about 180° by means of
the furnace d'. By this means the greater part of the carbonic acid and
sulphuretted hydrogen, and part of the ammonia contained in the said
gas liquor are driven off and pass by the pipe d' into the scrubber C
where the greater part of the ammonia is condensed by the descending
crude gas liquor and passes therewith by the pipe c' back to the still D,
while the sulphuretted hydrogen and carbonic acid gases with a little
ammonia
pass through the pipe e' into a scrubber E, which may contain
either sawdust moistened with sulphuric or other suitable acid, or coke,
through which water (preferably warm), cither with or without a small per-
centage of sulphuric or other suitable acid, is passed; such water cnters
by the pipe e² and passes out by the pipe e³. The sulphuretted hydrogen
and carbonic acid pass from the scrubber E by the pipe f¹ to a tank F
containing oxide of iron which takes up the sulphur of the sulphuretted
hydrogen, the carbonic acid escaping to the chimney by the pipe f*.
The purified gas liquor passes by the pipe d³ from the still D into the
heater B, and thence by the exit pipe b into a tank or reservoir. The
course of the gas liquor is indicated by black arrows, and the course of
the gases is indicated by red arrows.
By heating the gas liquor to a temperature of about 180°, as herein-
before described, instead of boiling such liquor, as described in the
Specification of my aforesaid Patent, No. 1369, A.D. 1868, I greatly
simplify the process of purification, and the apparatus necessary for
carrying it into effect, and effect a considerable saving of fuel.
Having now described the nature of my Invention, and the manner in
which the same is to be performed, I wish it to be understood that I do
not limit myself to the precise details herein-before described, as the
same may be varied without departing from the nature of my said.
Invention; but I claim as my Invention,―
Firstly. The modifications herein-before described of the process for
purifying gas liquor. described in the Specification of my aforesaid

page_text: Secondly. Effecting the partial purification of gas from its carbonic
acid, as herein-before described.
In witness whereof, I, the said Frank Clarke Hills, have hereunto.
set my hand and seal, this Ninth day of September, in the year
of our Lord One thousand eight hundred and seventy-four.
Witness,
H. H. MURDOCH,
7, Staple Inn,
London.
F. C. HILLS. (L.S.)