IMPROVEMENTS IN THE DISTILLATION OF COAL TAR, TAR OIL, RESIN, RESIN OILS. ALL HYDROCARBONS, PETROLEUM OR OTHER MINERAL OR VEGETABLE OILS, AND SPIRITS DERIVED THEREFROM
Year: 1863

page_text: LETTERS PATENT to William Cormack, of the City of Manchester, in the
County of Lancaster, Chemist, for the Invention of "IMPROVEMENTS IN THE
DISTILLATION OF COAL TAR, TAR OIL, RESIN, RESIN OILS. ALL HYDROCARBONS,
PETROLEUM OR OTHER MINERAL OR VEGETABLE OILS, AND SPIRITS DERIVED
THEREFROM."
Sealed the 18th November 1863, and dated the 23rd May 1863.
PROVISIONAL SPECIFICATION left by the said William Cormack at
the Office of the Commissioners of Patents, with his Petition, on the
23rd May 1863.
I, WILLIAM CORMACK, of the City of Manchester, in the County of Lan-
caster, Chemist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE DISTILLATION OF COAL TAR, TAR OIL, RESIN, RESIN OILS,
ALL HYDROCARBONS, PETROLEUM OR OTHER MINERAL OR VEGETABLE OILS, AND
SPIRITS DERIVED THEREFROM," to be as follows:-
The object of this Invention is to assist or improve the present well-known.
method of forcing over the products of distillation, which I accomplish by.
introducing a stream or flow of any atmospheric air, steam, or other vapour,
gas or gases, into the still, retort, or vessel in which the distillation is carried
on, either above or adjoining the surface of the matter which is to be distilled,
and by the force or expansion of such air, steam, or spirits I am enabled to
get over the products of distillation at a lower temperature than hitherto
[Price 8d.1

page_text: accomplished. I also use superheated steam, and cause it to be conducted to
the surface of the aforesaid fluids to be distilled in the same way as already
described.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Cormack in the Great Seal Patent Office on the
23rd November 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CORMACK, of the City of Manchester, in the County of Lancaster, Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of May, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Cormack, Her special licence that I, the said
William Cormack, my executors, administrators, and assigns, or such
others as I, the said William Cormack, 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 DISTILLATION OF COAL TAR, TAR
OIL, RESIN, RESIN OILS, ALL HYDROCARBONS, PETROLEUM OR OTHER MINERAL OR
VEGETABLE OILS, AND SPIRITS DERIVED THEREFROM," upon the condition (amongst
others) that I, the said William Cormack, my executors or administrators, by
an instrument in writing under
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 William Cormack, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the follow-
ing statement, that is to say:-
The object of this Invention is to assist or improve the present well-known
method of forcing over the products of distillation, which I accomplish by
introducing a stream or flow of atmospheric air, steam, or other vapour, gas

page_text: or gases, into the still, retort, or vessel in which the distillation is carried on,
either above or adjoining the surface of the matter which is to be distilled,
and by the force or expansion of such air, steam, or gases I am enabled to
procure the products of distillation at a lower temperature than hitherto
obtained, the aforesaid air, steam, or gases being used singly or combined.
I also use superheated steam or air, either singly or combined, and cause it or
them to be conducted to the surface of the aforesaid fluids or matters to be
distilled in the same way as already described.
The various hydrocarbons will have to be acted upon by different agents,
that is, for some, atmospheric air only will be the most suitable; for others,
steam only; for others, air and steam combined; for others, superheated steam
or superheated air, either singly or combined. For instance, in the distillation
of coal tar, the sulphide of ammonia and certain alkaline and saporrifying
properties which it contains have been the source of much trouble and impedi-
ment in the distillation of the light hydrocarbons, such as naptha or benzole.
which is obtained from the said distillation. The ammonia is not considered
of much value, for its presence impedes the distillation of the naptha or
benzole by giving rise to much. frothing and ebullition, which very often forces
its way out of the still and through the worm or condenser, and it is a well-
known fact that four-fifths of the fires that occur at tar works arise from the
blowing over of the light and tarry matters, which, reaching the furnace,
become ignited. In order to lessen or obviate the danger, and also to expedite
the distillation at a considerably lower temperature than usual, I cause a flew
or stream of air to act upon the surface of the matters to be distilled, which.
air, by its expansion, causes the products or vapours to be carried over as fast
as they are formed without frothing or ebullition. It will be evident that if a
vapour is formed within the still three or four inches above the surface of
the matter, and that vapour carried over into the condenser by the agents
employed, that there will be much less heat than if the said vapour was
raised to sixty inches high; for the necessary heat to raise the vapour from
four to sixty inches higher up in the still must be accumulated and derived
from the body of the fluid which causes the heavy and light hydrocarbons to
be brought over together. It is also evident that a vapour in the still of four
inches only above the surface matter, and that vapour carried over by the
agency of atmospheric air at an average temperature of 50° Fahrenheit, and
allowing only two volumes of air to one volume of the light hydrocarbon at a
temperature of about 180°, that the mean temperature of the combination of
vapours and air would be considerably below their boiling point before leaving
the still or before entering the worm or condenser, and would thereby assist

page_text: the condensation and purification 'within the still during the distillation. I'
continue' the air distillation until the whole of the light hydrocarbóns, such as
naptha or benzole and light oil, are brought over, I then disconnect the air
tube and distill the heavy 'oils by steam in a similar way as in the 'air process
described for the lighter hydrocarbons."
The apparatus I employ for conducting the air or steam to the surface of
the matter to be distilled is very simple in its nature, and will be readily
understood by referring to Figs. 1 and 2 on the accompanying Sheet of
Drawings, and to the letters of reference marked thereon, Fig. 1 being a
vertical section of an ordinary still having my conducting apparatus attached,
and Fig. 2 a plan of part of the same.
The air or steam is supplied to the interior of the still by the tube a
working through a stuffing box'b in the still head c, and is provided with an
elastic tube d for enabling it to "rise up and down, the elastic tube being
attached at the other end to the air or steam generator, there being a cock
near the supply for regulating the quantity of air or steam. To 'the tube is
fixed a socket e, closer at its lower end, and provided with a boss having eight
holes, in which are fixed eight pipes g, parallel with the surface of the matter
in the still, and in the tube a there are holes corresponding' with the holes in
the boss and pipes, which pipes are for the purpose of diffusing the air or
steam. To the bottom of the tube is fixed the ball or float h, which in some
cases floats upon the matter to be distilled, and maintains the pipes an
uniform distance from the surface, the ball being weighted according to the
specific gravity of the fluid or matter. In other cases the ball may be raised
above the fluid, so that the air or steam may be diffused at any height above
its surface. The pipes g are made of any required length according to the
size of the still; and for a circular still, of about six feet in diameter, the pipes
may extend about six inches from the centre of the tube a; but it is evident
that this length can be varied according to circumstances, and also that the
number of holes in the socket, and number and length of the tubes, can be
varied according to the shape of the still. Although I have shewn only one
float with its tube and pipes, two or more may be used for long stills, or those
of a waggon shape..
In waggon-shaped stills the tube k and stuffing box b, for guiding and
keeping tight the air tube, may be placed. independent of the still head, and
it is only in those stills where the still head is in the centre that it is necessary
pass the air tube through the still head. The air tube with its float must
be regulated by weights, to admit of its being raised or lowered as occasion
may require. For instance, if quality of products is desired to be obtained the
to

page_text: float must be raised higher up from the surface of the matter; on the other
hand, should the quality of product not be of consideration, then in that case
the float may be lowered, so that the air shall be impelled or propelled nearly or
quite on the surface of the matter during the distillation thereof. I may here
observe that the discharge of air or steam parallel to the surface, and about
four inches from it, is a very good arrangement in the distillation of all heavy
hydrocarbons, but in all light hydrocarbons, it is not essentially necessary to
convey the air or steam so near the surface; but in either case the vapours as
fast as they are formed are as speedily delivered over into the worm or con-
denser, and the quantity of air required to be conducted into the still will
depend upon its size and construction. For a still that contains about two
thousand gallons of fluid matter to be distilled the internal bore of the air
tube should not be less than one and a half inches in diameter, or for a three-
thousand gallon still the bore should not be less than two inches in diameter.
In order to ensure uniform pressure, I apply a meter or aeriometer between
the generator and the still. Such an aeriometer can be easily constructed; for
instance, two casks of different diameters, the larger one filled with water
similar to a water butt with the head out, the smaller cask the same with the
head out, but inverted and suspended within the other, dipping about eight
inches into the water, which gives a resisting pressure of about eight inches of
the column of water, which, if desired, can be always uniformly maintained, for
the overcharge of air into the aeriometer would make its escape through the
water. I do not confine myself to this eight-inch pressure, for a much higher
or lower pressure may be necessary. It will also be necessary to regulate the
air by a tap or stop-cock fixed in the discharge tube between the aeriometer
and the still: And when steam is the agent employed it should not be less
than five pounds on the inch, but a much greater pressure would be desirable,
the regulation of which can be easily managed by a stop-cock. In order to
enable the man in charge of the still to know when he is using too much or
too little steam, he should take a sample of the condensed product in a glass
tube, and notice the proportions of water and naptha or water and oil. For
instance, the proportion of condensed water to that of the naptha ought not to
exceed one-eighth part of the former to that of the latter, and with light
oil or during the distillation thereof the water ought not to exceed one-sixth,
and with heavy oil not more than one-fifth, but the proportions are varied
as required.
.
Having described my improvements in the distillation of coal tar by. the
application of air and steam, and now describe the way in which I distil coal tar
by the agency of steam alone, and for this purpose I employ superheated steam

page_text: in the still or vessel, and conduct it to the surface in a similar manner as in
the air process before described; that is, I carry over by superheated steam the
lighter hydrocarbons, such as naptha, benzole, and light oils, and continue the
distillation until the whole of the heavy oil is brought over. But I may here
state that in the distillation of naptha or benzole by steam from coal tar the
sulphide of ammonia which it contains is very nearly equal in fluid quantity
to the naptha or benzole, which would be very much diluted by the water of
condensation, and should the ammonia be valued as a consideration, then the
air process described in the fore part of my Specification must be adhered to.
Another part of my Invention in the distillation of coal tar is by the use of
steam and air combined, in which case I can use low-pressure steam not super-
heated. And in carrying out this part of my Invention I cause a jet or I
force a current of any atmospheric air through the vapour of steam in the
steam boiler, such current of steam and air combined I conduct to the surface
of the matter to be distilled in a similar manner to that before described. Or
I use steam and heated air combined in one tube before it enters the still.
Another part of my Invention relates to the distillation of coal tar by
suction or exhaustion, that is, instead of forcing air into the still by confined
apparatus, I cause the air tube to be open to the surrounding atmosphere, so
that the air shall be drawn in upon the surface, and the air and vapour
products be drawn from the still by any well-known mechanical contrivance,
either on the condenser or at the extreme end; and, further, the products can
be propelled forward into one or more receivers or vessels containing water or
either fluid for the absorbing of any product that might not wholly be con-
densed. And it must be understood that by this described process of suction
and exhaustion I do not mean it to convey that I produce a vacuum thereby
or any portion of a vacuum, as it will be evident that equilibrium will be
always maintained during distillation so long as the outer tube entering the
still is kept open to the outer atmosphere. And it must also be understood
that I deem it advisable in the distillation of all heavy hydrocarbons requiring
a higher temperature than from 480° to 500° Fahrenheit, that the air should
be disconnected and ordinary or superheated steam and instead; for in
some cases, if the fluid or matter were at a very high temperature, the oxygen
of the air might or would give rise to their oxidation. In the distillation of
the heavy oils air can be advantageously employed in their distillation as a
reducing agent, namely, the reduction of carbon and the production of a
lighter oil, as the fluid or matter to be distilled can be maintained at a con-
siderably higher temperature; and in carrying out this part of the process the
surface distillation must be limited or confined to retort distillation, or similar

page_text: limited surface. In the distillation of resin I prefer superheated steam or
superheated air and steam combined, or air and steam combined not super-
heated can be advantageously employed in their distillation, acting on their
surface in the same manner as already described in the fore part of my
Invention.
I now describe the way in which I distil Rangoon tar or oil, Pensyl-
vania, Canadian, or other mineral, petroleum, or vegetable hydrocarbons. I
refer first to Rangoon tar, which in the distillation thereof I employ steam
superheated and conducted to the surface as above described. As Rangoon
tar or oil is so highly charged with paraffin, were air to be employed as
the agent for surface distillation, it might or would give rise to foreign
productions not sought to be obtained. I therefore prefer commencing the
distillation by superheated steam upon the surface, and continue the same
until the whole of the fluid hydrocarbons are carried over, taking care of
course to separate the lighter from the heavier as the distillation proceeds.
Although I prefer superheated steam, air can be advantageously employed
in distilling the first products or lighter portion of the hydrocarbon.
In the distillation of the Pensylvania oil air can be employed as the agent
for such distillation in the carrying over the lighter products, as this oil is not
so highly charged with paraffin as Rangoon tar or oil, or I can use super-
heated steam instead of air, or steam and air combined.
In the distillation of Canadian oil air alone can be used exclusively, even to
the last stage of distillation, or steam superheated can be used exclusively
to the last stage of its distillation, or steam not superheated can be used in
combination with air, as already described.
In the distillation of vegetable hydrocarbons, vinons or alcohol hydrocarbens,
air will be found to act a most important part; as, for instance, the products
arising from the destructive distillation of wood, the acetons hydrocarbons
commonly known as pyroligneous acid, there is so little difference between
the volatility of this acetious hydrocarbon and water with which it is so highly
diluted that it cannot be concentrated by boiling or seperated by distillation, in
consequence of which it has been and is a source of great difficulty and expense
in obtaining that body in the pure state. The manufacturers are therefore
compelled to have recourse to chemical agents to obtain them in a pure state,
such as a metallic or alkaline base, and then to relieve them from these bodies
again by other chemical agents, which is attended with much expense and
great loss of the product sought to be obtained.
In order to obviate this, as well as to facilitate their ready production by
direct distillation from their highly diluted and crude state, I have recourse to
'

page_text: the cooling agency of atmospheric air acting on the surface as service
distillation in a similar manner as described in the distillation of light hydro-
carbons. And further, in the distillation of acetious hydrocarbons in their
crude state I employ an intermediate vessel placed between the still and
the pipe leading to the condenser, which vessel contains granulated animal
and vegetable charcoal, the acetons hydrocarben vapours passing through the
layers of charcoal assisted by the air is deprived of their empyreumatic odours
as well as their resinous oils, which constitute the base of their coloring and
fetid or smelling properties.
This part of my Invention will be clearly understood by referring to. Fig. 3
on the accompanying Sheet of Drawings, representing a transverse section of a
still having an additional vessel between the still and condenser. The still is
shewn at 1, the pipe leading to the condenser at m, and the additional vessel
at n, in the interior of which are placed sieves or perforated plates o, carrying
the layers of charcoal, there being as many sieves and layers as required, and
the top of the vessel is so formed that the sieves with their contents can be
entered and removed with facility.
It will also be understood that any hydrocarbon containing hydrocyanic
cyanogen, hydrosulphuretted, phosphunetted, or bi-sulphuretted hydrocarbens in
their combinations, and in which constitutes some of their impurities; the said
impurities can be freed and retained during the distillation therein of by passing
the vapours by the agency of the air through granulated animal and vegetable
charcoal, previously soaked or moisterred with strong alkaline solution, either
in the caustic or carbonated state, or the charcoal can be moistened with a
metallic solution the base of which is capable of taking up and acting upon
these impurities; or the alkaline and metallic combinations may be employed in
a dry state, as above described, and during the distillation thereof, and in the
imanner set forth.
In the distillation of alcohol or other light or similar spirit, atmo-
speric air will be found to act a very important part from the low tem-
perature in which they can be distilled over. For instance, three volumes
of air at 50° Fahrenheit to one volume of vapour alcohol at 170° to 180°,
this would lower the temperature so far below the boiling point that any
essential oil would be easily separated from the spirit during distillation.
For this purpose I use an intermediate vessel connected to the top of the
still as shewn in Fig. 3, and containing granulated animal and vegetable
charcoal in the similar way as set forth and described in the acetous hydro-
carbon process of distillation.
And it will be observed that I prefer using the animal and vegetable char-

page_text: coal in equal proportions, not mixed but separate, the lower portion near the
still to contain the vegetable charcoal, and the upper part to contain the
animal charcoal.
Having now described the nature of my said Invention, and in what manner
the same is to be performed, I desire it to be understood that I do not claim
the mechanical arrangements and apparatus before described, except so far as
they may be employed in and for the purposes of my said Invention; but what
I claim is the distillation of coal tar, tar oil, resin, resin oils, all hydrocarbons,
petroleum or other mineral or vegetable oils, and spirits derived therefrom, by
introducing air or steam either singly or combined, or superheated steam
by itself or combined with air or other vapour, gas or gases, into the still,
retort, or other vessel in which the distillation is carried on, either above
or adjoining the surface of the matter which is to be distilled, in the manner
above described.
In witness whereof, I, the said William Cormack, have hereunto set my
hand and seal, this Twenty-third day of November, One thousand eight
hundred and sixty-three.
20
Signed, sealed, and delivered by the
within-named William Cormack, in
the presence of
E. T. HUGHES,
Patent Agent,
London.
WM. CORMACK. (L.S.)