IMPROVEMENTS IN MANUFACTURING AND PURIFYING CERTAIN GASES, AND IN PREPARING CERTAIN SUBSTANCES FOR PURIFYING THE SAME
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANK
CLARKE HILLS, of Deptford, in the County of Kent, Manufacturing Chemist,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-fourth day of
January, One thousand eight hundred and. fifty-two, in the fifteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Frank Clarke Hills, my exors, adiñors, and assigns, Her especial
license, full power, sole privilege and authority, that I, the said Frank Clarke
Hills, my exors, admors, and assigns, or such others as I, the said Frank
Clarke Hills, my exors, admors, or assigns, should at any time agree with, and
no others, from time to time and at all times during the term of years therein
expressed, should and lawfully might, make, use, exercise, and vend, within
England, Wales, and the Town of Berwick-upon-Tweed, my Invention of.
"IMPROVEMENTS IN MANUFACTURING AND PURIFYING CERTAIN GASES, AND IN
PREPARING CERTAIN SUBSTANCES FOR PURIFYING THE SAME;" in which said
Letters Patent is contained a proviso that I, the said Frank Clarke Hills, shall
cause a particular description of the nature of my said Invention, and in what
manner the same is to be performed, by an instrument in writing under my
hand and seal, to be inrolled in Her Majesty's High Court of Chancery

page_text: within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Frank Clarke Hills, have ascertained and set forth the nature of my Invention,
and the manner of carrying the same into effect, in and by the following
description thereof :-
My first improvement consists in a mode of obtaining gas for illumination
from tar or other liquid hydro-carbons and steam, or the gases resulting from
the decomposition of steam. For this purpose I provide a still with a man-
hole door for cleaning out the residuum. About two feet of tar or other
liquid hydro-carbon is kept in the still, and, as it distils over, more liquid is
run into the still in a continuous stream. To produce the best effect a fire
should be kept up under the still to keep the liquid in the still hot, and steam
(or the gases resulting from its decomposition), preferably heated as high as
possible by passing through red hot pipes or by any other convenient means, is
passed into the liquid in the still. The steam or gases will carry off with it a
portion of the hydro-carbon in vapour, the quantity of which may be regulated
by the heat of the fire under the still. The steam and hydro-carbonaceous
vapour pass from the still into a furnace or retort (preferably placed upright)
filled with coke, and maintained at or as nearly at a white heat as possible,
whereby the steam and hydro-carbonaceous vapour will be to a great extent
decomposed, and a large quantity of carburetted hydrogen and carbonic oxide
.will result, which may be mixed with coal gas obtained in the ordinary
manner. The still will require to be occasionally cleaned out to remove the
pitch and incrustation. The gas may be freed from any carbonic acid which
may be formed by any of the ordinary means.
My second improvement is for the following methods of decomposing steam,
or, steam mixed with hydro-carbonaceous vapour. I make an upright furnace
or. retort of any convenient size, say eight feet high by eighteen inches wide,
-lined with fire bricks, and filled with coke, or anthracite coal, or other similar
carbon, which is kept nearly or quite white hot by a blast of hot air admitted
at the bottom from an air pump. At the top and bottom of the furnace is
placed a pipe in the interior of another pipe. The top interior pipe is for
conducting the air from the air pump to the bottom of the furnace, to which
it descends through the exterior pipe close to the furnace. The bottom
interior pipe. is. for conducting the steam to be deposited into the furnace.
These pipes are placed inside the others for the purpose of heating the air and
steam to be employed, the heated air and gas being sucked out of the furnace

page_text: through the exterior pipes. The action of the pump is as follows:-At the
first stroke of the pump air is forced through the top interior pipe into the
bottom of the furnace, and at the same time gas is sucked out of the furnace
into the other end of the pump through the top exterior pipe, thereby making
the air pumped in very hot by abstracting the heat from the gas pumped out,
and at the same time cooling the gas. These pipes should be of at least double
the contents of the air pump, so that no hot gas reaches the pump. At the
reverse stroke of the pump the air which was forced into the furnace through
the top interior pipe is sucked out through the bottom exterior pipe, and, at
the same time the gas that was sucked out at the top of the furnace is forced
back again into the furnace, bringing it again in contact with the hot carbon
for the purpose of decomposing any remaining steam and carbonic acid into
hydrogen and carbonic oxide. At the second stroke of the pump the decom-
posed air which has been sucked out of the furnace is forced into the
atmosphere, and at the same time fresh air is sucked into the other end of the
pump, to be forced into the furnace as at first by the next stroke of the pump,
during the stroke of the pump, by which the decomposed air is forced into the
atmosphere, and fresh air is being sucked into the pump for a fresh blast.
Steam for making gas is admitted into the furnace in any desired quantity by
opening a cock or valve worked by the machinery which drives the pump.
This steam is to be conducted through the bottom interior pipe, and will
become heated very hot by abstracting the heat from the decomposed air which
fills the exterior pipe. It will then pass into the highly heated carbon, and, by
coming in contact therewith, and passing through it, it will be decomposed; at
the same time it will drive upwards, and thence into the hydraulic main, the
gas contained in the upper part of the retort. By this means each end of the
pump becomes alternately the end for forcing the fresh air into the furnace,
and proper valves for regulating all the several passages must be placed to
effect the purpose, worked by any appropriate machinery, which, as it may be
endlessly varied, it is needless to describe. When tar or other liquid hydro-
carbon is to be used, as before described, to furnish gas, the steam may be
heated in the way just mentioned, and may then be passed into the hot tar
previous to entering the furnace, to carry up with it the tar vapour to be
decomposed along with the steam by the incandescent carbon. Instead of
working only one furnace or retort by the air pump, any number of retorts
may be worked simultaneously by having the air pump and pipes large enough
for the heating and cooling processes, with smaller branch pipes to each retort.
The capacity of the pump and retorts will of course depend entirely upon the
quantity of steam and tar to be decomposed. Instead of drawing the air in

page_text: °
and out of the furnace, as described, a continuous blast may be kept up
through the furnace until the carbon is raised to a white heat; the blast is
then to be suspended, the passage for the products of combustion closed, and
steam, either alone or mixed with the vapour of tar or other hydro-carbon, or
with a small quantity of atmospheric air (say four per cent.), and preferably
heated as hot as possible, is to be admitted as long as the carbon in the furnace
remains sufficiently hot to decompose it. A fresh blast of air is then to be
admitted as before, to make the carbon as hot as at first, when steam, or steam
and hydro-carbonaceous vapour, is to be admitted as before. The furnaces by
this mode of operation should be much larger than before described. Instead
of only working one furnace, it will be better to work two or more furnaces, so
that one may be heating by the blast of air from the pump, while steam
is being decomposed in another. The waste heat may be used for any
desired purpose.
My third improvement consists in another method of decomposing tar or
other liquid hydro-carbon. I cause the tar, &c. to drop from the top of a
vertical retort (kept at a high heat) upon a stratum or a succession of strata
of hot coke, supported upon gratings in the retort in such a manner that the
tar, &c., which is not decomposed may percolate through the strata of coke,
and fall into a well attached to the bottom of the retort, which is to be kept
cool, and from whence the tar is to be pumped up to be used over again. The
hydrogen, &c., from the decomposition of steam may be admitted into this
retort at the bottom to combine with the gas formed from the tar, &c.
Instead of vapourizing the tar to decompose it, the gas containing the tar
vapour, as it comes from the ordinary retorts, may be treated as follows:-One
retort out of each bed of retorts (the hotter the better) is to be furnished with
a false bottom of bars placed an inch or two from the bottom. These bars
should be placed a little apart, so as to form a grating to support the coke
with which the retort above the bars is to be nearly filled. The rich gas
containing the tar vapour being the first products from the distillation of the
coals, is to be passed from the other retorts by means of pipes furnished
with valves, &c. under the grating above described, where it may be mixed
with the gases formed by the decomposition of steam, and both will then pass
together between the bars, and then through the hot coke to the upper part
of the retort, and thence to the hydraulic main. The decomposed steam unités
with a part of the gaseous hydro-carbon and more gas is produced.
My fourth improvement is for purifying gas for illumination, and consists in
mixing with lime or magnesia, or both, when these substances are used as
purifying agents, and used in dry lime purifyers, a portion of sulphate of lime

page_text: or muriate of lime, which when damped will retain the consistence of a damp
powder. The proportion of the salts of lime to be added to the lime or
magnesia is to be regulated by the quantity of ammonia and carbonic acid
contained in the gas to be purified, care being taken not to add too much, so
as to make the mixture clog or become impervious to the free passage of the
gas. The refuse purifying material will be valuable as a manure.
of
My fifth improvement consists of a method of burning carbonate of lime
formed in purifying gas by lime, so that it may be re-used for the purification
gas. For this purpose I subject the waste lime from dry lime purifiers, and
which contains a large portion of carbonate of lime, to a sharp red heat in a
reverberatory furnace, constructed as follows:-The bed of the furnace is
formed in two stages, the hinder one being higher than the fore one. These
beds are composed of fire tiles or bricks. The fire is situated under the fore
bed, and is fed from the side; and the flame and heated air, after circulating
under the fore bed, pass off at the opposite side, and sweep, first over the fore
bed, and then over the hinder bed, from whence they descend and pass under
the hinder bed in their passage to the chimney. The carbonate of lime, &c.
is first placed on the upper bed to dissipate any moisture it may contain, and
to warn it, and is then discharged into the lower bed, where being heated
above and below to a sharp red heat, the carbonic acid is quickly dispelled.
Carbonate of magnesia will of course part with its carbonic acid by this treat-
ment more readily than lime.
My sixth improvement is for methods of rendering fit for re-use in purifying
gas the sulphates and oxychlorides of iron, and the different oxides of iron
capable of purifying gas either mixed or unmixed with more porous materials,
which, after having been so employed, are become inert. To re-use any of the
oxides or the salts of iron named above, which after taking sulphur from the
gas are capable of being renovated by atmospheric air, I employ the following
method, which is an improvement upon that contained in my Patent of the
Twenty-eighth of November, One thousand eight hundred and forty-nine, for
renovating oxides of certain metals. Supposing there are four or more
purifiers, such as are used for dry lime, containing the said oxides, either
granulated, as herein-after described, or mixed with more porous materials,
such as charcoal or sawdust, I allow crude gas to pass through the material in
one or more of such purifiers until the material has become foul or inert.
I then, by means of an air pump, or by any other convenient mode, force into
the purifiers, along with the gas to be purified, a current of atmospheric air, in
the proportion of about four volumes of air to one hundred volumes of gas,
which proportion may be regulated by the use of meters, &c. The air mixed

page_text: with the gas in its passage through the foul material will re-oxidize the iron,
which will immediately react upon the gas, and thus a simultaneous and con-
tinuous process of deoxidizing and re-oxidizing the iron will be carried on, and
the material will continue to purify the gas without the labour and expense of
frequently taking it out of the purifier to renovate it, and without the loss of
time that would take place even if it were renovated in the purifier by shutting
off the gas and admitting atmospheric air to it. As these materials after long
use have a tendency to become clogged or stopped up by the deposition of
sulphur, &c., so as to render it difficult for the gas to pass through them, I
employ the following means to keep them open, so as to defer as long as pos-
sible the labor and expense of taking them out of the purifiers:-I make a
frame to fit the interior of the purifier, with triangular notches on its upper
surface to receive a series of triangular bars, which are placed therein with
their flat sides uppermost, forming a false bottom or grating on which the
material is to be placed. The frame is supported upon arms, excentrics, or in
any other suitable way, so as to admit of its being raised or lowered. Above
the moveable false bottom are one or more ranges of thin flat wrought-iron
bars placed edgewise, two or three inches apart, across the purifier, so as par-
tially to support the purifying material. When from continued action the
materials have become somewhat clogged, the false bottom is to be lowered a
little, and with it will descend the lower portion of the materials; but the
upper portion being partially sustained by the parallel bars will not settle to
the same extent, and thus the mass becomes loosened and broken up and
again rendered easily permeable to the gas. When the said oxides are no
longer capable of being readily renovated by air, and are become useless for
purifying gas, they may be treated in the following way, whereby they will be
made again available for the purpose of purification:-The sulphur and other
impurities are to be burnt off or got rid of in any convenient way, and the
remaining oxides of iron are to be mixed with soda or potash, or either of
their carbonates, or with nitrate of soda or potash in a strong solution; two
parts of oxide and one of caustic soda answers well. This mixture is then to
be made nearly red hot in à furnace, or in any convenient way, and is after-
wards to be used for the purpose of purifying gas from cyanogen. I prefer
placing this mixture in the first purifier, through which the gas passes from
the condenser, to obtain the largest amount of cyanogen, which combines with
the alkali and iron. It is best to allow the mixture to remain in the said
purifier until it will take up no more cyanogen. It is then to be taken out
of the purifier, and the cyanogen compounds may be washed out for use.
Instead of burning or heating the spent oxides with the alkalies, such alkalies,

page_text: The
or, preferably, their carbonates, may be mixed with fresh oxides, or the soluble
salts of iron, to render them fit for purifying gas from cyanogen; this mixture
is then to be placed in a purifier, and when it ceases to take up cyanogen and
sulphur it is to be taken out for renovation and be made damp by adding
a solution of the said alkalies or their carbonates as soon as possible
after it is taken out of the purifiers. After renovation, the mixture is to
be again put into the purifier to take up more cyanogen, and this process
may be repeated until the material can no longer be profitably used, after
which the compounds of cyanogen may be washed out for use. Another
method of rendering the spent oxides, which will no longer profitably purify
gas and which have not been mixed with alkalies, fit for re-use, is to wash
them with a weak solution of soda or potash, or, preferably, the carbonates of
soda or potash, to combine with the cyanogen which has been taken from the
gas by the material, so as to obtain the cyanogen compounds for use.
sulphur is then to be burnt off from the oxides, or got rid of in any convenient
way, and the oxide will be fit for re-use as before described. Instead of mixing
any material, such as sawdust, breeze, &c., with the said oxides, &c., I prefer
to granulate them, so that the gas may easily pass through them, and being
unmixed with other bulky materials, a much larger quantity of gas can be
purified in the same space, and the sulphur may also be more easily obtained
from them. Some of the oxides may be granulated by mixing them with
water into a sort of clayey or doughy consistence, then pressing it into thin
cakes, which, after drying in the sun or at a moderate heat, are to be broken up
to the required size. The dust may be separated by sieves and be mixed up
again. The oxides may also be made granular, by putting them in powder
with a little water into a stamping press, which by percussion will make them
into a solid state; they may then be broken up as desired. The oxides
which are burnt or beated with the alkalies may be made granular in the
furnace by the action of the heat. The processes herein-before described for
the purification of gas are preferably carried on in dry lime purifiers, but they
may also be used in wet lime purifiers by mixing the materials with water.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that what I claim is,--
First, the method as described of obtaining gas by carrying up, by means
of steam or the gasses resulting from the decomposition of steam, assisted by
heat, the vapour of tar, or other hydro-carbons, into highly heated retorts filled
with coke or other such carbon to be decomposed.
Secondly, I claim decomposing steam or steam and hydro-carbonaceous
vapour, by first heating coke or other carbon in furnaces or retorts to a great

page_text: heat by means of air forced or drawn into the furnaces by any convenient
methods, and then admitting steam or steam and hydro-carbon to be
decomposed, and which admission of air and steam, &c. to be alternately
employed.
Thirdly, I claim the method of treating or decomposing tar or other hydro-
carbons, either alone or with the gases formed by the decomposition of
steam, by causing the tar to drop upon red hot coke, as before described.
Fourthly, I claim the decomposition of tarry vapour in ordinary gas by
passing it (either mixed or uninixed with the gases resulting from the decom-
position of steam) through red hot carbon in the manner described.
Fifhly, I claim for purifying gas the use of a mixture of sulphate or
muriate of lime with either lime or magnesia or both, but I do not claim
either of these substances alone.
Sixthly, I claim the mode of burning carbonate of lime or of magnesia as
described, so that it may be re-used for purifying gas.
Seventhly, I claim the method of renovating hydrated oxides of iron, or
any other oxides of iron that are capable of being renovated by atmospheric
air (after they have become inert, by taking sulphur from the gas) by
admitting or forcing atmospheric air into the purifiers at the same time and in
conjunction with the gas to be purified.
Eighthly, I claim the method described for loosening the said purifying
material in the purifiers (when it becomes too solid or impervious to the gas)
by means of a moveable false bottom in the purifier on which the material
rests.
Ninthly, I claim rendering the spent oxides which are no longer capable of
being profitably renovated by air fit for re-use to purify gas from cyanogen, by
first freeing them from sulphur and other impurities, and then using them in
combination with the alkalies and salts mentioned, after heating them together
to nearly a red heat.
Tenthly, I claim, for the purpose of purifying gas, the using and re-using
any oxides, sulphurets, or salts of iron in combination with the alkalies before
mentioned, and adding a fresh portion of alkali to the said mixtures as often
as they require renovation.
Eleventhly, I claim obtaining cyanogen compounds from spent oides which
have not been mixed with alkalies, and rendering the said oxides fit for re-use
for purifying gas, by first washing them with a weak solution of soda or
potash or their carbonates, so as to obtain the compounds of cyanogen
taken up by the material, and then burning off or otherwise removing the
sulphur.