IMPROVEMENTS IN THE MANUFACTURE OF GAS AND IN. OBTAINING RESIDUAL PRODUCTS FROM SUCH MANUFACTURE, AND IN APPARATUS TO BE USED IN SUCH MANUFACTURE
Year: 1870

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 MANUFACTURE OF GAS AND IN.
OBTAINING RESIDUAL PRODUCTS FROM SUCH MANUFACTURE, AND IN APPARATUS
TO BE USED IN SUCH MANUFACTURE."
Sealed the 21st June 1870, and dated the 21st February 1870.
PROVISIONAL SPECIFICATION left by the said Frank Clarke Hills
at the Office of the Commissioners of Patents, with his Petition,
on the 21st February 1870.
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 MANUFACTURE OF GAS AND
IN OBTAINING RESIDUAL PRODUCTS FROM SUCH MANUFACTURE, AND IN APParatus
TO BE USED IN SUCH MANUFACTURE," to be as follows:-
My Invention relates to a process described in the Specification of
Letters Patent granted to me, and bearing date 25 April 1868, No. 1369,
by which process gas liquor was to a certain extent deprived of sul-

page_text: phuretted hydrogen, carbonic acid, and other impurities, and when thus
purified was used for purifying gas.
My present Invention consists, firstly, in distilling the purified gas
liquor obtained by the process above referred to, and in passing the
ammoniacal vapour resulting from the distillation into gas for the
purpose of purifying the same. The said vapour may be introduced
into the gas at the exit end of the hydraulic main, or between it and
the condensers, so as to combine with the sulphuretted hydrogen,
carbonic acid, and other impurities in the gas, and be condensed with
them in the condensers with the ordinary gas liquor. Instead of
passing the distilled ammonia in the form of vapour into the gas the
said ammonia may be condensed and be then introduced in a liquid
form into scrubbers through which the gas is passed. By distillation I
render-available-for-the-purification-of-gas the weak gas liquors which
pass from the terminal or other scrubbers, and which without distillation
would be too weak for the purpose. Gas liquors may be distilled before
they are purified, and the impure ammonia thus obtained may be con-
densed into liquid and afterwards purified (by means of the patent
process herein-before referred to), and be used to purify the gas in an
ordinary scrubber, or the said gas liquors may be purified first and then
be afterwards distilled, and the ammonia obtained may be condensed
into liquid in condensers and be afterwards used to purify the gas in an
ordinary scrubber.
Gas may
be wholly purified by the process herein-before described, or
the purification may be carried to any desired extent, and finished by
passing the gas through oxide of iron or other purifying material in the
usual way,
My Invention consists further in utilizing the sulphuretted hydrogen
which has been driven off from the gas liquor during the progress of
purification described in the Specification herein-before referred to.
According to this part of my Invention the sulphuretted hydrogen is con-
ducted from the last condenser or purifier into a furnace with atmospheric
air, the said sulphuretted' hydrogen being passed either over or through
the fire in such furnace, so that the said sulphuretted hydrogen may be
burnt or decomposed and be converted by the process into sulphurous
acid gas. This gas may be condensed either in water or in gas liquor
so as to saturate such liquor. When the said gas is condensed in water
it forms liquid sulphurous acid, and this may be used in an additional

page_text: condenser in communication with the last of the condensers shown in
the Drawing appended to the Specification herein-before referred to for
purifying gas. liquor. The said sulphurous acid will combine with and
fix the ammonia in the said condenser and prevent its escape. The
said sulphurous acid may also be used to saturate gas liquor so as to
form a useful salt of ammonia, or the said sulphurous acid may be used
for purifying gas.
When sulphurous acid is used to saturate the ammonia which escapes
from the last of the condensers used for purifying gas liquor according
to my former process, such sulphurous acid should be run into an
additional condenser in a regulated quantity so as to make a continuous
process, and the saturated ammonia should at the same time be con-
tinuously run out so as to keep the liquid in the condenser at a uniform
level.
My Invention consists further in using coal in the form of powder or
dust for the manufacture of gas in the following manner:-I construct
and use a retort composed of a horizontal retort with a vertical retort or
pipe or with several such vertical retorts or pipes, into which I introduce
the powdered coal through a valve or through valves at the upper part
of the vertical retort or retorts. The said powdered coal is wholly or
partially decomposed or carbonised as it falls through the said vertical
retort or retorts into the horizontal retort, such portions of the said coal
as are not wholly carbonized in their passage through the vertical retort
or retorts being completely carbonized in the horizontal retort.
5 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 18th August 1870.
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 Twenty-first day of February, in the
year of our Lord One thousand eight hundred and seventy, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give

page_text: and grant unto me, the said Frank Clarke Hills, Her special licence
that I, the said Frank Clarke Hills, my exccutors, 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, excrcise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANU-
FACTURE OF GAS AND IN OBTAINING RESIDUAL PRODUCTS FROM SUCH MANUFACTURE,
AND IN APPARATUS TO BE USED IN SUCH MANUFACTURE," upon the condition
(amongst others) that I, the said Frank Clarke Hills, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain 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, firstly, to a process described in the Specifica-
tion of Letters Patent granted to me, and bearing date 25th April 1868
(No. 1369), by which process gas liquor was purified more or less
perfectly from sulphur and cyanogen compounds, and from carbonic
acid and other impurities, and when thus purified was used for purifying
gas.
My present Invention is as follows, and consists, firstly, in distilling
the purified gas liquor obtained by the process above referred to so as to
obtain the ammonia it contains in a stronger form, and in passing it in
the form of vapour into the gas to combine more or less with the
carbonic acid and with the sulphur and cyanogen compounds in the gas,
and thereby to render the gas more pure. The impurities taken up by
the ammonia will be condensed with it in the ordinary gas liquor in the
condensers and scrubbers, and if when condensed into liquid with the
gas liquor it has not taken up its full dose of impurities it may be run
through a scrubber again to take up more, Instead of passing the

page_text: ammonia in the form of vapour into the gas the said ammonia may be
condensed from the stills into liquid by being brought into contact with
water or weak purified gas liquor in a worm or in a scrubber or in any
other convenient way, and the liquid ammonia thus obtained when of a
proper strength should be introduced into the scrubbers through which
the gas is passed for the purpose of purifying the gas. Eight or ten
ounce liquor answers very well. The hot waste liquor running out from
the bottom of the still deprived of its ammonia may be used to heat the
cold gas liquor to be distilled in any convenient or well-known way so as
to economize the steam used for distilling, if steam is used, and as steam
can be obtained from the waste heat of gasworks I prefer to use steam for
the purpose of distilling the gas liquor. The form of the still I prefer
to use is what is known as a column still, in which the gas liquor to be
distilled runs in at the top in a continuous stream, and then over the
diaphragms or media contained in the still, and then out at the bottom
of the still deprived of its ammonia by the current of steam admitted
into the bottom of the still and passing upwards and driving off
the ammonia in vapour at the top of the still, as is well understood.
The ammoniacal vapour thus driven off may be condensed in any
suitable condenser, but I prefer a condenser constructed as herein-after
described. The said condenser consists of a rectangular tank (with
a tight cover) of any required size, (say, two feet wide, four feet deep,
and eight or nine feet long,) in which tank are placed as many pipes
(preferably about three inches in diameter) as can well be got into the
said tank. The said pipes arc arranged longitudinally in successive rows
one row above another, a little space being left between each pipe. The
ends of the pipes are caulked or cemented into sockets, cast on or fixed
to the end plates of the tank; and a deeper socket is cast on or fixed to
the said ends around every two adjoining pipe sockets, the pipes in which
are connected by means of caps or covers caulked or cemented into the
outer sockets aforesaid. The pipes are thus connected to one another so
as to form one continuous length of pipe. The liquor to be distilled
enters the lowest row of pipes, and after passing backwards and.
forwards from pipe to pipe through this row ascends to the next row
and passes through it, and thence passes in the same way from row to
row until it passes from the last pipe of the top row through another pipe
into the top of the still to be distilled. Horizontal plates are fixed across
the tank between each row of pipes so as to form a succession of

page_text: chambers, openings being made at alternate ends of the respective
plates so as to form a continuous passage through which the hot.
ammoniacal vapour from the still which is to be condensed passes back-
wards and forwards from the top of the series of chambers to the bottom.
The said vapour is thus caused to surround the pipes contained in the
successive chambers and to heat the liquor in the said pipes, the
said vapour being at the same time cooled and more or less condensed
into liquor by the cooler surfaces of the said pipes. The condensed
liquor will then run out of the bottom chamber for use, and should
there still be any vapour of ammonia not condensed it may be
passed into the water scrubber to be there condensed.
If the gas
liquor to be distilled is not sufficiently heated by passing through the
pipes in the condenser which are surrounded by the hot vapour from the
still it may be passed-through-the-pipes-of-another-vessel-of-the-same-
description as the said condenser, but which for distinction I call a
heater and cooler, as it heats the gas liquor to be distilled and cools the
waste gas liquor which runs away deprived of its ammonia from the
bottom of the still. The heater and cooler is exactly similar to the said
condenser except that there is no need of the horizontal plates across the
tank to separate the rows of pipes. The gas liquor to be distilled after
being somewhat heated in the condenser is to be passed through the
series of pipes placed in the tank of the heater and cooler, and from
thence into the top of the still, whilst at the same time the waste hot
liquor which runs away from the bottom of the still deprived of its
ammonia is to be run into the tank of the heater and cooler. The hot
liquor will thus surround all the pipes in the tank through which the
gas liquor to be heated passes to the still and which will thus become
very hot. The hot waste liquor from the still should be run into the
top part of the tank of the heater and cooler, and as it cools it should
be run out at the bottom part of the said tank through a pipe bent
upwards above the level of the highest pipe in the tank, so that all the
said pipes may be covered by the liquor. The gas liquor to be heated
after leaving the condenser should enter the lowest row of pipes in the
heater and cooler, and after passing through the whole scries should pass
out from the top row into the top part of the still. As the hot waste
liquor from the still descends in the tank of the heater and cooler the
said waste liquor will be cooled by imparting its heat to the pipes
through which the gas liquor passes to be distilled. The heater and

page_text: cooler should be placed at a lower level than the bottom of the still so
that the hot waste liquor may run from the bottom of the still into the
top part of the tank of the heater and cooler.
Figure 1 of the accompanying Drawings is a front elevation of part
of one of the end plates of the tank of the condenser herein-before
described showing the pipes through which the gas liquor passes, and
the sockets in which the said pipes are fixed; Figure 2 is a front
elevation showing the way in which two adjacent pipes are connected
by means of the cap or cover herein-before referred to; Figure 3 is a
vertical section (taken on the line Z, Figure 2); and Figures 4 and 5 are
side and front elevations respectively of the aforesaid cap or cover. The
same letters and figures of reference indicate the same parts in Figures
1, 2, 3, 4, and 5.
A is part of one of the end plates of the tank; B, B, are sockets cast
on or fixed to the said plate, in which sockets are inserted the ends of
pipes C, C, the said sockets being of such a diameter as to leave annular
spaces b, b, for caulking or cement between the 'said sockets and the
said pipes; D, D, are deeper sockets, each of which encloses two of the
sockets B, B; E is one of the caps or covers herein-before referred to.
In fitting the pipes into the tanks the ends of the said pipes are first
inserted in the sockets B, B, and are fixed therein by caulking or cement,
which is filled in level with the ends of the said pipes. The caps E are
then placed upon the ends of the pairs of pipes in the sockets D, D, and
are caulked or cemented into the said sockets, and constitute passages
through which the liquor to be distilled flows from one pipe to another.
The pipes are thus connected at their front and rear ends so as to con-
stitute one continuous length of pipe through which the liquor passes,
the said liquor entering the end pipe of the lowest row of pipes, and
passing backwards and forwards from pipe to pipe until it arrives at the
end of the said row, whence it passes through a cap or cover E (arranged
vertically as shown) to the next row of pipes, and so on throughout the
series. By distillation I render available for the purification of gas any
purified gas liquor which would otherwise be inconveniently weak for
that purpose.
The ammonia driven off from the weak gas liquors by
distillation may be condensed either in water or in purified gas liquor,
so as to make it of almost any required strength, and by mixing a little
of this strong ammoniacal liquor with the gas liquor to be used for
purifying the gas almost any desired strength of liquor for purifying,

page_text: Therefore
may be obtained.
If the same gas liquor is repeatedly used after
successive purifications for purifying gas it will become weaker each
time, because a little water is mixed with it in the terminal scrubber to
prevent any escape of ammonia each time it is purified.
unless the said gas liquor has taken up more ammonia from the gas
while purifying it it should be strengthened by the addition of strong
ammoniacal liquor obtained by distillation as aforesaid, so as to keep
the strength up to a uniform standard.
In purifying the said gas liquor, instead of placing the stills or con-
densers as shown in the Drawings in the Specification of the Patent,
No. 1369, A.D. 1868, herein-before referred to, I prefer to place them
one above another, as shown in the accompanying Drawing, as less heat
is required to purify the gas liquor by this arrangement, and the
apparatus is made more compact.
Figure 6 of the accompanying Drawings represents in vertical section.
a series of stills or condensers arranged as above described.
A1, A2, A3, A4, are the stills, which are mounted one above another, as
shown; B is the reservoir containing the crude gas liquor to be distilled,
which said liquor is conveyed by a pipe b¹ passing through the heater
and cooler C to the still A¹; a¹, a³, a³, a, are what I term " dipping
trays," into the first of which the gas liquor from the pipe 6¹ passes.
The said liquor flows over the side of the tray a¹ into the body of the
still, whence it passes by the pipe a³ into the tray a². From this tray
the said liquor passes to the body of the still A³, thence through the
pipe a to the tray a³, thence to the body of the still A³, thence through
the pipe a to the tray a, thence to the body of the still A, and thence
through a pipe as to the boiler D, which is heated by means of a steam
pipe d', d¹, as described with reference to a similar boiler in the Speci-
fication of my aforesaid Patent, No. 136968; From this boiler the
purified gas liquor passes through a pipe d³ to the heater and cooler C,
and thence through the exit pipe c¹ to tanks or reservoirs, or to the
scrubbers in which the said gas liquor is to be used for purifying the
gas. The sulphuretted hydrogen, carbonic acid, and any ammonia driven
off by the boiling pass through the pipe d³ to a dome a formed in the
tray a, thence through the gas liquor under the bottom of the said tray
and through the pipe a¹º to the dome a", thence under the bottom of the
tray a³ and through the pipe a to the dome a¹³ thence under the
bottom of the tray a² and through the pipe a to the dome a¹, and
10

page_text: thence under the bottom of the tray a¹ through the pipe e¹ to a water
condenser E (the use of which is to condense the ammonia);" from the
condenser E the gases are passed through a pipe e into a water scrubber
F in order to condense any remaining ammonia. From the said
scrubber the said sulphuretted hydrogen and carbonic acid gases escape
by the pipe f¹. The water from the scrubber passes through the pipe ƒ³
into the condenser E, and thence by pipes e³, e, to the tray a¹. The
course of the gas liquor is indicated by black arrows, and that of the
gases is indicated by red arrows. Instead of the heater and cooler C
a heater and cooler constructed as herein-before described for heating gas
liquor to be distilled and for cooling the waste liquor may be used. Gas
may be wholly purified from most of its impurities by means of purified
gas liquors applied in scrubbers as above described, or the gas may be
only partly purified by this means, that is to say, the purification may
be carried to any convenient extent by this means and be afterwards
finished by means of oxide of iron or other purifying material in any
convenient way. To purify gas by means of purified gas liquor I prefer
to pass the gas first through a scrubber down which ordinary cold gas
liquor is caused to percolate. The gas should then be passed through a
scrubber or scrubbers down which purified gas liquor is caused to
percolate, and if the scrubber is not of sufficient size to enable the
purified gas liquor to take up its full dose of impurities the said liquor
may be run through a succession of scrubbers to take up more impurities
from the gas. After passing through the purified gas liquor scrubbers
the gas should be passed through one or more water scrubbers to prevent
any escape of ammonia before the gas enters the oxide of iron or other
material used for completing the process of purification in case the gas
should not be wholly purified by means of the gas liquor. Any con-
venient and efficient spreader may be used for distributing the purifying
liquids over the top surface of the scrubbers, but it is very important
where the purification of gas is to be effected almost entirely by liquids.
that the best form of distributor or spreader of the liquid should be used.
I prefer to use distributing apparatus constructed as herein-after
described and illustrated in Figures 7, 8, 9, 10, and 11 of the accom-
panying Drawings. The said apparatus for this purpose consists
essentially of two annular chambers or vessels (subdivided as herein-
after explained), which chambers or vessels are mounted one above the
other and receive rotatory motion from suitable gearing, the office of the
upper vessel (which I term a "meter") being to measure and deliver

page_text: "
to the lower vessel (which I term a distributor") the liquid used, and
the office of the "distributor" being to distribute or spread such liquid
in concentric rings over the cokc or other medium in the scrubber.
Figure 7 is a plan of my said apparatus, and Figure 8 represents the
said apparatus in side elevation as applied to a scrubber; Figures 9, 10,
and 11 represent details herein-after referred to. The same letters and
figures of reference indicate the same parts in Figures 7, 8, 9, 10,
and 11.
A is the upper part of the scrubber, to which is affixed the frame B;
C is the meter herein-before referred to, which said meter is represented
separately in plan in Figure 9, and consists of a circular tray, on which
is formed an annular trough or vessel divided into compartments
_c₁,_c²,_c³,_c^,_(sce_Figure 9) each of which is supplied in succession with
purifying liquid from a reservoir D by means of a pipe d. The said
meter is mounted on a hollow shaft or axis c, which turns in a bearing
in the frame, and receives motion from a shaft E by means of a train of
toothed wheels e¹, e², c³, e¹. The said shaft is turned by means of a
band pulley c³ or of a winch. F is the distributor, which is represented
separately in plan in Figure 10, and in transverse section in Figure 11,
and receives rotatory motion from a bevil pinion e which gears into a
bevil wheel e on the shaft fon which the said distributor is mounted,
which said shaft passes through the hollow shaft c. The said distributor
consists of a circular tray, on which are formed annular troughs
f, f, ƒ³, f (see Figures 10 and 11), which troughs correspond in
number with the compartments of the meter, and are supplied in
succession with purifying liquid from the compartments c¹, c³, c³, c³,
respectively by means of pipes cº, c³, c³, c³. ƒ³, ƒ³, ƒ", ƒ³, are pipes
through which the liquid passes to the coke or other medium in the
scrubber; ƒ³, ƒ³, are spreaders by which the said liquid is distributed
and spread in successive concentric rings over the coke or other medium
in the scrubber. The number of the annular troughs in the distributor
and of the compartments in the meter must be proportioned to the
diameter of the scrubber, i.e., the greater the diameter of the scrubber
the more troughs there must be in the distributor, there being a com-
partment in the meter for every trough in the said distributor, and the
length of each compartment must be proportioned to the area over which
the purifying liquid is to be spread by the pipe of the trough supplied
by each compartment. Thus, for example, if the ring made by the

page_text: liquid passing from the trough f' is to be four times the diameter of the
ring made by the liquid passing from the trough f¹ the chamber c* must
be made four times the length of the chamber c¹, so as to supply to the
trough four times the quantity of liquid that is supplied to the
trough f¹ by the compartment c¹, and the relative speeds at which the
meter and the distributor arc driven must be such that the latter shall
make a complete revolution while the shortest compartment of the
meter is passing under the pipe d.
The action of the apparatus is as follows:-While the compartment c¹
is passing under the pipe d the purifying liquid passes from the said
pipe into the said compartment, thence through the pipe c to the
trough f, and thence through the pipe f³, by which the said liquid is
spread in a ring on the coke or other medium in the scrubber. By the
time that the distributor F has made one revolution the compartment c²
comes under the pipe d, and liquid therefrom passes into the said com-
partment and through the pipe c' to the trough f, and thence through
the pipe f by which the said liquid is spread in another ring on the
coke. The troughs f³, f*, are in like manner supplied in succession with
liquid through the compartments c³, c', respectively, and spread the said
liquid over the coke by means of the pipes f³, f³. The said liquid is
thus supplied in concentric rings to the coke, which is equally moistened
throughout.
My Invention consists further in utilizing sulphuretted hydrogen
which has been driven off from the gas liquor during the process of
purification described in the Specification herein-before referred to.
According to this part of my Invention the gases driven off from the
gas liquors during purification are conducted from the last still, condenser,
or purifier or from the water scrubber by means of pipes into a furnace,
where the sulphuretted hydrogen is to be burnt with a proper admixture
of atmospheric air. The said sulphuretted hydrogen may be passed over the
fire either through tubes made red hot or over or through the fire itself in
such a manner that by the addition of atmospheric air the sulphuretted
hydrogen may be burnt or decomposed and be converted by the process
into sulphurous acid gas. This gas may be passed through pipes from
the furnace into water to form liquid sulphurous acid. This liquid
sulphurous acid may be used instead of water in the water condenser or
purifier in communication with the last still, purifier, or condenser shown
in the Drawing appended to the Specification herein-before referred to

page_text: and shown in Figure 6 of the accompanying Drawings, for purifying gas
liquor. The said sulphurous acid will combine with the ammonia taken
up in the said condenser forming sulphite of ammonia, and will prevent
the escape of the ammonia, and sulphur will generally be precipitated.
To make a stronger solution of sulphite of ammonia it may be run out
of the condenser when the sulphurous acid is saturated by the ammonia,
and more sulphurous acid gas may be passed into the said solution so as
to have acid in excess, when it may again be introduced into the con-
denser to take up more ammonia. This process may be repeated as long
as it is found to be convenient, or the solution of sulphite of ammonia
may be caused to run in and out of the condenser in a continuous stream,
the said solution having a supply of sulphurous acid gas passed into it
in another vessel. The solution may be caused to pass from one vessel
to the other by pumps_or_by_other_convenient_means. Sulphur_will_be
precipitated in the solution, which sulphur should be allowed to settle
out before the solution is evaporated to form a salt. Free sulphuretted
hydrogen driven off from the gas liquor from the boilers or stills by
coming into contact with the sulphurous acid will cause a double
decomposition, and the sulphur of both should be precipitated.
Instead of condensing the sulphurous acid gas into water and allowing
the sulphuretted hydrogen driven off from gas liquor to pass through it
the two gases themselves may be brought together in equivalent pro-
portions (say two volumes of sulphuretted hydrogen to one volume of
sulphurous acid) and be passed through a tube or flue of any required
size, or the mixed gases may be passed through a succession of chambers
or vessels connected together by pipes or flues in order that the gases
may decompose one another and precipitate sulphur. When it is
intended to obtain sulphur from the gases in this way the sulphuretted
hydrogen burnt to form the sulphurous acid should be kept as free as
possible from extraneous gases during its combustion. Therefore I
prefer in this case to effect the combustion of the sulphuretted hydrogen
in tubes or chambers heated externally instead of passing it through the
furnace. The said mixed gases (which should contain a certain amount
of moisture) may be drawn through the flues or chambers (in which
sulphur is deposited as above described) by the draught of a chimney, or
the said gases may be drawn or forced through by a rotating fan or other
convenient means. The sulphuretted hydrogen and sulphurous acid gas
should be introduced by pipes close together into one end of the flue or
chambers so as to insure their being perfectly mingled together during their

page_text: If more
con-
passage through the said flue or chambers. From the fluc or chambers
the remaining gases should be passed through an oxide of iron purifier
to take up any sulphuretted hydrogen that might not be decomposed,
and it would be better in mixing the gases to have a little excess of
sulphuretted hydrogen over the sulphurous acid gas.
venient, instead of burning part of the sulphuretted hydrogen to form
sulphurous acid, some of the sulphur obtained from the double decom-
position of sulphurous acid and sulphuretted hydrogen may be burnt
in any convenient apparatus, and the sulphurous acid resulting from the
combustion of the sulphur may be brought into combination with the
sulphuretted hydrogen set free from the purified gas liquor in such a
manner that by their mutual decomposition more sulphur may be
obtained. Or the sulphurous acid may be obtained from the combustion
of cheap pyrites or sulphur ore, and the sulphurous acid gas thus
obtained may be mixed with the sulphuretted hydrogen to obtain sulphur
from both. The proportions of the said gases may be regulated by
means of cocks, valves, or meters. The said sulphuretted hydrogen when
converted into sulphurous acid gas, as described, may be used to saturate
gas liquor. The sulphurous acid gas may be forced or drawn into the
gas liquor by mechanical means, or it may be drawn upwards through
scrubbers by the draught of a powerful chimney, while the gas liquor is
caused to descend through the scrubbers to meet and come into contact
with the sulphurous acid gas until it is saturated. It may then be
evaporated sufficiently to form a salt if desired, or the said sulphuretted
hydrogen when converted into sulphurous acid may be used for purifying
gas. The gas after being deprived of its ammonia in any convenient
way, but still retaining sulphuretted hydrogen, may be passed through
purifiers containing the said sulphurous acid in solution, and the said
gas should afterwards be passed through a purifier containing oxide of
iron. The sulphurous acid will decompose the sulphuretted hydrogen
in the gas, and sulphur will be precipitated. When sulphurous acid is
used to saturate the ammonia which escapes from the last of the boilers,
stills, or condensors used for purifying gas liquor as herein-before
described, such sulphurous acid should be run into the water condensers
in a regulated quantity, so as to make a continuous process; and the
saturated ammonia should at the same time be continuously run out
so as to keep the liquid in the condenser at a uniform level.
My Invention consists further in using coal in the form of powder or
dust for the manufacture of gas in the following manner :-I construct

page_text: and use retorts of the following description:-Each retort should have a
horizontal part at bottom with a mouth piece as in ordinary retorts. At
the top of the horizontal part of the retort one or more vertical pipes or
retorts is or are fixed so as to form one retort. The vertical parts of the
retorts may
be of the same diameter as the horizontal part, but the
horizontal part should be of greater depth than width. I prefer to make
the vertical parts of the retorts slightly conical instead of cylindrical, the
largest part being at the bottom. The powdered coal is to be introduced
into the retort at the top of the vertical parts thereof in such a manner
that it falls down through the said vertical parts in a continuous gentle
stream. This may be effected by means of a revolving archimedian
screw or creeper working in a tight wrought-iron case furnished with a
hopper with double valves to prevent the escape of gas, one being shut
when the other is open for introducing the coal. The aforesaid screw or
creeper is worked by suitable machinery. Or the coal may be intro-
duced into the top of the retorts in any other convenient way, care being
taken that means are provided for cleansing the vertical parts of the
retorts in case they become incrusted with carbon. The powdered coal
in falling through the vertical parts of the retorts becomes more or less
decomposed, and the gas and tarry vapour formed may be taken into a
hydraulic main and condensers in the same manner as the gas from
ordinary gas retorts. If any coal was not decomposed whilst falling
through the vertical parts of the retorts it would be completely car-
bonized in the horizontal part, and the quantity of coal admitted into the
retort must be regulated to effect this object. Rich gas may be obtained
from the tar condensed in the hydraulic main and condensers by running
it in a continuous stream through several stills, so that the whole of the
gas that the powdered coal will make may be obtained. To effect this I
take the tar and run it through a series of stills, say 3, 4, or 5. Each
succeeding still should be placed at a higher level that the preceding one,
and the stills should be connected by pipes in such a manner that the
tar will run into the top still and from thence down through the
series of stills and then out of the bottom still.
The vapour arising from the distillation of the tar in the first still may
be condensed by itself by means of a worm or otherwise, as the oil or
spirit obtained is of more value than gas obtained from it would be.
The vapour from the other stills is to be conducted by suitable pipes
into one or more of the vertical parts of the retorts already described for
decomposing the powdered coal, but in this case the retort should be

page_text: filled with pieces of coke. By coming into contact with the red-hot
surfaces the vapour from the tar will be decomposed into gas, or a separate
retort of the same description may be filled with pieces of coke, and the
tar vapour may be caused to pass up or down through the said retort
and between the pieces of coke therein contained, which being kept
red hot will decompose the tar vapour into gas. The tar being deprived
of its morc volatile parts by running through the stills will be converted
into pitch in the lowest still, from whence it may be run out in a con-
tinuous stream into a vessel, which would keep it liquid until it was
full, when it might be run into a mass to cool. Instead of running the
tar through several stills one still only may be used after the light spirit
is distilled off from the tar, but in this case the still should be longer
than broad and the still should be divided by partitions fixed transversely
across its length so as to divide the still into 3 or 4 or more parts.
There should be small openings made in the bottom of the partitions
for the tar to pass from one compartment to another until it reaches
the compartment where it is to be made into pitch. Openings must
also be made in the upper part of the partitions for the vapour from cach
compartment to escape to the decomposer. The still might be 3 or 4
times as long as it is broad. The fire for heating the still should be
placed at the end where the pitch is to be formed, at which end the
heat should be greatest, and the flues should be taken from the fire-
place to heat the other parts of the still.
The series of tar stills above described may be heated by one fire or by
several fires. If one fire only is used it should be placed under the
bottom still, and flues from it might be taken to work the other stills, or
a separate fire may be used to cach still, or the light spirit may be
distilled off from the top still by steam heat. Of course ordinary coal
tar formed in the usual way may be converted into rich gas by being
treated as above described.
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 and
illustrated, as the same may be modified without departing from the
nature of my Invention; but I claim as my Invention,-
Firstly. Distilling purified gas liquor, and passing the resulting
ammoniacal vapour into gas for the purpose of purifying the said gas.

page_text: Secondly. Distilling the said purified gas liquor and condensing the
resulting ammoniacal vapour either in gas liquor or in water to be added
to gas liquor, and using the ammoniacal solutions thus obtained for the
purification of gas, essentially as described.
Thirdly. The improved construction and arrangement herein-before
described and illustrated in Figure 6 of the accompanying Drawings of
the stills or condensers used in connection with the boiler for purifying
gas liquor.
Fourthly. The improved arrangement herein-before described and
illustrated in Figures 1, 2, 3, 4, and 5 of the accompanying Drawings 1
for connecting the ends of the pipes of the “condenser" and of the
"heater and cooler" herein-before described, so as to admit of a
number of such pipes being arranged very close together in the tank and
communicating with each other, essentially as described.
Fifthly. The improved apparatus herein-before described and illus- 1
trated in Figures 7, 8, 9, 10, and 11 of the accompanying Drawings for
distributing water or other purifying liquid over the coke or other medium
contained in scrubbers used for purifying gas.
Sixthly. Utilizing essentially as herein-before described, the sul-
phuretted hydrogen given off by the gas liquor during the process of 2
purification herein-before referred to.
Seventhly. The improved method of carbonizing coal and converting
most of the volatile constituents of tar into light spirit and gas, as
described.
In witness whereof, I, the said Frank Clarke Hills, have hereunto 2
set my hand and scal, this Sixteenth day of August, in the year
of our Lord One thousand eight hundred and seventy.