IMPROVEMENTS IN THE UTILIZATION OR EMPLOYMENT OF CERTAIN MINERAL OIL PRODUCTS FOR THE MANUFACTURE OF ILLUMINATING GAS
Year: 1879

page_text: LETTERS PATENT to William Young, of Clippens, in the County of Renfrew,
North Britain, for the Invention of "IMPROVEMENTS IN THE UTILIZATION OR
EMPLOYMENT OF CERTAIN MINERAL OIL PRODUCTS FOR THE MANUFACTURE OF
ILLUMINATING GAS."
PROVISIONAL SPECIFICATION left by the said William Young at the Office
of the Commissioners of Patents on the 25th June 1879.
WILLIAM YOUNG, of Clippens, in the County of Renfrew, North Britain.
"IMPROVEMENTS IN THE UTILIZATION OR EMPLOYMENT OF CERTAIN MINERAL OIL
PRODUCTS FOR THE MANUFACTURE OF ILLUMINATING GAS."
This Invention relates to improvements in the utilization or employment of
certain mineral oil products for the manufacture of illuminating gas, and has for one
of its objects to utilize certain of the bye-products from the refining of paraffin oil,
viz., acid and alkaline tars, that they may be advantageously used for the manufac-
ture of illuminating gas.
Many attempts have been made to utilize these bye-products for the manufacture
of gas, such as removing the sulphuric or other acid from the acid tar by boiling up
with water, allowing to settle, and removing the sub-stratum of acid liquors, treating
the remaining greasy tar with lime, or other alkali, or the soda tars, to remove the
remaining acid, and running the tar thus neutralized into a retort heated to bright
redness for the manufacture of gas; or by mixing the neutralized tar with small
coal or dross, and charging the mixture into the gas-producing retort; or by sub-
jecting the neutralized tar to distillation and using the resulting oils in a manner
similar to that described with the tars. These processes, however, have, for various
reasons, failed.
The crude neutralized tar has a most abominable odour, and when mixed with
small coal it presents such a surface to the air as to pollute it and become a nuisance.
The mixture was difficult to prepare and handle from its pasty character, and from
the stiff pasty mess adhering to the shovels in charging, and when the tar was run
into the retort it foamed up and soon filled the retort with a spongy mass of carbon
which prevented the continuance of the operation. The crude neutralized tar also

page_text: '
always contained sulphur compounds which led to the rapid saturation of the
purifying materials.
The distillation of the tar entailed such an expense as to prevent its use except
in cases where expense was not an object. The oil had also a very objectionable
odour, which in many cases prevented its use.
By this Invention these defects are overcome in the following manner :-The tar
or tars are neutralized in the usual way, and are then run or fed into a still and the
more volatile portions distilled out. This volatile portion consists principally of
creosote compounds and compounds containing sulphur, which possess anti-septic
properties and which are useful for impregnating wood for its preservation, such as
railway sleepers, wood rails, &c. The portion remaining in the still, which is thus
mado almost free from sulphur compounds and almost odourless, is cooled till
vapours cease to be evolved, and is then run out into a receptacle, where it is con-
solidated and is ready to be broken up and mixed with coal, and used in the usual
way for gas making.
Or the hot tar residue in the still may be run off into a mixer of any convenient
form, and there be combined with small coal, peat, or any other material which gives
a poor gas when distilled by itself.
Another part of this Invention has for its object the removal of sulphur com-
pounds from coal gas other than sulphuretted hydrogen. These sulphur compounds
consist principally of bi-sulphides of carbon and others not well understood, and at
present they are eliminated from the gas by means of hydro-sulphide of lime. As
the sulphur compounds are in the gaseous or vapourous form, and diffused through
the gas in very small quantities, and as the hydro-sulphide of lime is a solid, it
follows, from the well known fact of the difficulty in getting a solid to act chemically
on a gas without the intervention of a solvent liquid, that the hydro-sulphide of
lime must be spread over a very large area, and the gas be passed at a very slow
speed before the sulphur compounds can be acted upon.
Now I have discovered that the more volatile portion of the distillate of paraffin
oil, or the oils recovered from the waste gases produced in the manufacture of
paraffin oil from coal or shale, or the more volatile of the petroleums, as also the
more, volatile of the oils derived from other sources, such as coal-tar, wood-tar,"
candles, pitch, &c., have a greater solvent action upon the sulphur compounds
referred to, and may be used for their elimination in a variety of ways.
For instance, the hydro-sulphide of lime may be moistened with the hydro-carbon
fluid, either previous to or after its introduction to the purifier; or some of the other
hydro-sulphides of the alkalies may be used which can partake of the liquid form,
such as the hydro-sulphide of soda, ammonia, or potash. The hydro-carbon fluid
absorbs the sulphur compounds with great avidity, and in turn parts with them to
the hydro-sulphido of the alkali or alkaline earth in a manner similar to that in
which water absorbs hydro-sulphuric and carbonic acid from the coal gas, and
transfers it to the lime or other purifying agent.
The hydro-carbons can also absorb ammoniacal gas, and can be made to purify in
that way, or the hydro-carbon fluid may be employed to absorb out the sulphuretted
compounds from the gas in one vessel, and may be treated in a second arrangement
for the recovery of the sulphur compounds by fractional distillation, or by treatment
with hydro-sulphide of the alkalies, or by combining with alcohol or other substances
having a higher solvent action for the sulphur compounds than the hydro-carbon
fluid employed.
When the sole object is to remove sulphur compounds from the gas the hydro-
carbon fluid which it is preferred to employ is that portion of the distillate of
paraffin or petroleum spirit which will neither evaporate into the gas nor yet
abstract the illuminating power from it at ordinary atmospheric temperatures, but
when the hydro-carbon fluid is low in price, and can be profitably employed as a
carburetting fluid, then a more volatile portion of the distillate may be advantageously.
employed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Young in the Great Seal Patent Office on the 24th December
1879.
WILLIAM YOUNG, of Clippens, in the County of Renfrew, North Britain.
"IMPROVEMENTS IN THE UTILIZATION OR EMPLOYMENT OF CERTAIN MINERAL OIL
PRODUCTS FOR THE MANUFACTURE OF ILLUMINATING GAS."
This Invention relates to improvements in the utilization or employment of
certain mineral oil products for the inanufacture of illuminating gas, and has for
one of its objects to utilize certain of the bye-products from the refining of paraffin
oil, viz., acid and alkaline tars, that they may be advantageously used for the
manufacture of illuminating gas.
Many attempts have been made to utilize these bye-products for the manufacture
of gas, such as removing the sulphuric or other acid from the acid tar by boiling up
with water, allowing to settle, and removing the substratum of acid liquors, treating
the remaining greasy tar with lime or other alkali, or the soda tars to remove the
remaining acid, and running the tars thus neutralized into a retort heated to bright
redness for the manufacture of gas; or by mixing the neutralized tar with small
coal or dross and charging the mixture into the gas-producing retort; or by
subjecting the neutralized tar to distillation and using the resulting oils in a manner
similar to that described with the tars. These processes however have for various
reasons failed.
The crude neutralized tar had a most abominable odour, and when mixed with
small coal it presented such a surface to the air as to pollute it and become a
nuisance. The mixture, from its pasty character, was difficult to prepare and
handle, the stiff pasty mass adhering to the shovels in charging, and when the tar
was run into the retort it foamed up and soon filled the retort with a spongy mass
of carbon, which prevented the continuance of the operation. The crude neutralized
tar also always contained sulphur compounds, which led to the rapid saturation of
the material employed for the purifying of the gas.
The distillation of the tar entailed such an expense as to prevent its use except
in cases where expense was not an object. The oil had also a very objectionable
odour, which in many cases prevented its employment.
By this Invention these defects are overcome in the following manner :-The tar
or tars are neutralized in the usual way, and are then run or fed into a still and
the more volatile portions distilled out. This volatile portion consists principally
of creosote compounds and compounds containing sulphur which possess antiseptic
qualities, and which are therefore useful for impregnating wood for its preservation,
such, for example, as railway sleepers and wood rails. The portion remaining in
the still, which is thus made almost free from sulphur compounds and almost
odourless, is cooled till vapours cease to be evolved, and is then run out into a
receptacle where it is consolidated, and is ready to be broken up and mixed with-
coal and employed in the usual way for gas-making.
Or the hot tar or residue in the still may be run off into a mixer of any convenient
form, and there combined with small coal, peat, or any other material which, when
distilled by itself, gives a poor gas; or the neutralized tars may be mixed with the
Emall coal or other solid material in a vessel or still beated externally by a furnace,
the mixed mass of tar and small coal being kept agitated by means of rotating
stirrers or their equivalent, whilst the more volatile portions are distilled out.
This possesses the advantage that the tars penetrate thoroughly into the coal or
other poor material with which they are mixed, at the same time that the water
which may be contained in the solid material is eliminated or driven out. The
mixture is then run into a receptacle, as above described, where it is cooled and
.broken up.
Another part of this Invention has for its object the application of the more

page_text: volatile portion of the distillate of mineral oil, or the hydrocarbon recovered from
the waste shale gases, for the removal of sulphur compounds from coal gas other
than sulphuretted hydrogen, and which are at present removed only in part, and
that at great expense and with considerable difficulty. These sulphur compounds
consist principally of bi-sulphides of carbon and others, the composition of which
is not well understood.
The processes hitherto adopted for the removal from coal gas of these sulphur
compounds may be divided into two classes, that in which they are removed by
chemical affinity, or by causing them to combine with a substance having an affinity
for them, such as by passing ammoniacal gas in a caustic state into the gas in the
bydraulic, and subjecting the whole to condensation; or, secondly, by using the
hydrosulphide of one of the alkalis or alkaline earths. Hydrosulphide of lime has
hitherto had the preference, and is employed, as is well known, in the ordinary dry
lime purifiers.
By the second class of processes the sulphur compounds are decomposed by heat,
either in the presence of water, vapour, or hydrogen gas, the sulphur present being
in most cases, converted into sulphuretted hydrogen, which is removed either by
lime or by hydrated oxide of iron.
.
Now I have discovered that the more volatile portion of the distillate of paraffin
oil, or the oils recovered from the waste gases produced in the manufacture of
paraffin oil from coal or shale, or the more volatile of the petroleums, have a great
solvent action upon the sulphur compounds referred to, and may be used for their
elimination in a variety of ways.
For instance, the hydrocarbon fluids- referred to possess a solvent action for
ammoniacal gas, and therefore a solution may easily be formed by passing
ammoniacal gas through the fluid or shaking the fluid up with a strong aqueous.
solution of ammonia. The hydrocarbon ammoniacal solution so formed may be
applied in the ordinary form of scrubbers, or the solution may be used in an
ordinary wash vessel when such would be available; but in this case, as in all others
where the hydrosulphides of the alkalis are employed to chemically combino with
the sulphur compounds, it would be best applied after the gas has undergone
purification from carbonic acid, as this gas would combine with the ammonia or
other alkali to form the oxycarbonate to the exclusion of the sulphide of carbon.
The separation of the sulphocarbonate of ammonia formed in the solution of hydro-
carbon fluid may be readily effected by simply bringing it into contact with water,
which would dissolve it out; and as the fluid is much lighter than water it rises to
the surface and can bo easily decanted to be again saturated with ammoniacal gas-
to be re-employed for further treating the gas.
The affinity of simple hydrated' ammonia and other alkalis for sulphide of carbon
is not nearly so great as for the alkalis after being united with sulphuretted
hydrogen to form bydrosulphide of the alkalis. Now the hydrocarbon fluid herein
referred to also freely dissolves hydrosulphuric acid. Such being the case, the
gases after having been freed from carbonic acid by means of lime, but left con-
taining sulphuretted hydrogen, have only to be passed into such an alkaline
solution of ammonia, to form the hydrosulphide of ammonia, which would imme- 4
diately absorb the sulphur compounds dissolved out of the gas by means of the
volatile hydrocarbon fluid.
The hydrosulphides of the alkalis and alkaline earths are not soluble in this
bydrocarbon fluid recovered from the gas, and therefore we cannot form a solution
with lime or soda as we can with the ammoniacal gas; but, as is well known, it is
not in all cases necessary that the fluid employed for bringing about a union
between a gas and a solid, or between a solution of a chemical and a gas, should be
a solvent for both. In the great majority of cases it is found more important that
the fluid be such as to dissolve the gas and reduce it to the liquid state, as in this
state it can readily combine with another liquid holding in solution the chemical 5
substance with which it is desired to combine the gas, or the solid substance being
wetted with the solvont of the gas, it acts as the medium for reducing the gas into

page_text: a liquid, and transferring it to the solid, with which it may enter into combination
and assume the solid form.
At present hydrosulphide of lime is almost universally employed when tho
sulphur compounds are removed from the gas. It will be evident, therefore, that
to wet the line compound with this fluid would have the effect of bringing about
a rapid union between the sulphur compounds and the lime salt, as the fluid would
dissolve the sulphide of carbon present in the gas in the gascous or vapourous form,
converting it into liquid form, and bringing it into such close contact with the
hydrosulphide of lime, that the chemical affinity would come into action, and the
sulphide would combine with the lime salt to form the carbosulphide of calcium.
The wetting of the hydrosulphide of lime can be accomplished by spraying the fluid
through the gas as it enters the purifier in the usual well understood manner; or
the fluid may be sprinkled over the hydrosulphide of line by a pipe passing through
the purifier cover.
Should it be desired to employ the hydrosulphide of soda in place of lime, then
that salt being soluble in water, could be used as an aqueous solution combined or
mingled with the hydrocarbon fluid, and the whole pumped through an ordinary
scrubber. When the hydrosulphide of soda gets saturated with sulphide of carbon,
it can be separated from the fluid, and the sulphide of carbon recovered by adding
a strong acid to the soda salt.
But gas contains many other substances having sulphur in their composition
besides sulphide of carbon, and which the hydrosulphide of the alkalis does not
remove, but which this hydrocarbon removes rapidly. This fact has been observed
long ago, for when a hydrocarbon fluid was employed for carburetting the gas used
in the street-lamps in London, it was observed that however pure the fluid hydro-
carbon might be from sulphur compounds when put into the lamp to be carburetted,
there was always left a dark-residue, having a most abominable smell, and which,
when distilled, gave evidence by lead paper that it contained sulphur in its consti-
tution. A hydrocarbon fluid similar in character also collects in drip-boxes, and
on the surface of the water in gasholder tanks, which, as is well known, has a most
offensive sinell, and which contains sulphur in its constitution.
In the same manner as we employ water to absorb ammonia from our gas, so we
may also employ this or a similar hydrocarbon fluid for the absorption of those
sulphur compounds which escape other modes of purification. So soon as this fluid
approaches saturation with sulphur compounds, it becomes necessary to treat them
for their elimination either by fractionally distilling them and removing the portion
containing the sulphur compounds; or by simply distilling and treating the
distillate with suitable chemicals (acid and alkali), or by dissolving out the sulphur
compounds with methylated alcohol or other fluid which is a solvent for the sulphur
compounds, but which is not or is feebly a solvent for the hydrocarbons employed,
or by distilling them and subjecting them to the vapour of water or hydrogen gas
at such a temperature as will bring about their decomposition, which would to all
intents and purposes be a modification of the second set of processes referred to in
this Specification, and which would be practicable from the small quantity of
vapour requiring treatment, compared with the gas from which the sulphur com-
pounds were derived. The sulphur compounds are thus removed by simple
absorption, and as it is not necessary to previously remove the carbonic acid from
the gas, oxide of iron may be made the sole purifying agent.
All the hydrocarbons, such as those distilled from wood tar, crude or palm pitch,
bitumen, and coal tar, have the property of absorbing those sulphur compounds;
but none of them possesses so many necessary characters as this fluid or analogous
fluids derived from petroleum. First and principally, they are lower in price;
secondly, they are largely composed of paraffin and other hydrocarbons which are
not themselves acted upon readily by such chemicals as may be employed for the
elimination of sulphur compounds; thirdly, they can be had in large quantities;
and fourthly, being volatile, they are diffused through the gas, and very much
improve its illuminating power at a trifling cost.

page_text: Should any difficulty however be experienced in obtaining a supply of hydro-
carbon fluid, the napthas distilled from tho. tars could be easily employed, thus
affording another proof that in the crude gas itself we have present all the
materials necessary for its complete purification. Thus we have the tar to remove
sooty matters, and when properly applied, the water would remove every trace of
ammonia; the ammonia, all carbonic acid and sulphuretted hydrogen; and the
napthas, the other sulphur compounds, thus providing a gas which would, so far as
the noxious products of combustion are concerned, be unobjectionable.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the system, mode, or inanner in or under which the same is or may be used
or practically carried into effect, I would observe in conclusion that what I consider
to be novel and original, and therefore claim as the Invention secured to me by the
herein before in part recited Letters Patent is,―
First. The treatment of acid and alkaline tars resulting from the refining of
paraffin oil for their utilization in the manufacture of illuminating gas, by heating
the said tars after being neutralized in the usual way, so as to distil out the moro
volatile portions, and afterwards treating the residue according to either of the
ways hereinbefore described, or comingling the said tars after being neutralized in
the usual way with small coal, peat, or other gas making material, and heating the
mixture till the more volatile portions of the tar are distilled off, all as herein
described.
Second. The employment of the more. volatile portion of the distillate of mineral
oil (or other hydrocarbons) for the removal of sulphur compounds from illuminating
gas, essentially as hereinbefore described.
In witness whereof, I, the said William Young, have hereunto set my hand
and seal, this Twenty second day of December, in the year of our Lord
One thousand eight hundred and seventy nine.
EM TALLATIO