Improvements in the Distillation of Mineral Oils and like Products, and Apparatus for that Purpose.
Year: 1889

page_text: Date of Application, 24th June, 1889
Complete Specification Left, 20th Mar., 1890-Accepted, 26th Apr., 1890
PROVISIONAL SPECIFICATION.
Improvements in the Distillation of Mineral Oils and like Products,
and Apparatus for that Purpose.
We, JAMES DEWAR of No. 1 Scroope Terrace, Cambridge in the County of
Cambridge, Professor of Chemistry, and BOVERTON REDWOOD of 'Ballard's Lane
Finchley in the County of Middlesex, Analytical Chemist, do hereby declare the nature
of this invention to be as follows:-
In distilling mineral oils such as petroleum, paraffine residues and the like, in order
to separate the lighter oils suitable for lamps from the heavier oils which cannot
conveniently be used for illuminating purposes, there is a very large residue of heavy
oil. Attempts have been made to obtain lighter oils from this residue by causing the
vapour generated in the still boiler to pass a heavily loaded valve so that the vapourisa.
tion takes place under considerable pressure. It has also been proposed to arrange
the still boiler with its upper part cooled so that the less volatile portions of the vapour
may become more or less condensed and fall back into the hot liquid below, this mode
of operating being commonly termed "cracking." Both these methods are objection.
able, the former on account of the irregularity of the distillation, and the latter on
account of the waste of heat in conducting the cracking process and the slowness and
insufficiency of the results.
Our invention relates to a method of conducting the distillation by suitable apparatus
in such a manner that we get the benefit of regular vaporisation under high pressure,
and that we may at the same time get such advantage as can be obtained from
cracking. For this purpose we arrange a suitable boiler and a condenser in free.
communication with one another, without interposing any valve between them, but we
provide a régulated outlet for condensed liquid from the condenser. We charge and
keep charged the space in the boiler and condenser that is not occupied by liquid
with gas under considerable pressure, it may be with air, but it is preferably with
carbonic acid gas, or other gas that cannot act chemically on the matter treated.
The distillation and condensation being thus conducted under considerable pressure,
which can be regulated at will, we obtain from the heavy residue a quantity of more
or less light oil suitable for illuminating purposes, which cannot be obtained by dis.
tillation under atmospheric pressure. We may also arrange the upper part of the
still boiler so as to operate according to the cracking method above referred to, the
cracking in this case taking place under high pressure instead of being carried on as
it usually is under atmospheric pressure.
Dated this 4th dow of Tunn 1000
Improvements in the Distillation of Mineral Oils and like Products,
and Apparatus for that Purpose.
We, JAMES DEWAB, of No. 1 Scroop Terrace, Cambridge in the County of Cambridge,
Professor of Chemistry, and BOVERTON REDWOOD of Ballard's Lane, Finchley, in the
County of Middlesex, Analytical Chemist, do hereby declare the nature of this
Invention and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:-
In distilling mineral oils, such as natural petroleum or similar oil made from
-shale-coal or other bituminous substances, in order to separate the lighter oils

page_text: "
suitable for lamps or other purposes from the heavier oils, there is frequently a very
large residue of heavy oil.
Attempts have been made to obtain lighter oils from such residues or from heavy
natural petroleums by causing the compressed vapour generated in the still boiler to
pass a heavily loaded valve or a regulating stop cock to the condenser, so that the
vaporisation might take place under considerable pressure.
2
It has also been proposed to arrange the still boiler with its upper part cooled so
that the less volatile portions of the vapour may become more or less condensed and
fall back into the hot liquid below, this mode of operating being commonly termed
cracking. Both these methods are objectionable, the former on account of the
irregularity of the distillation, and the latter on account of the waste of heat in con-
ducting the "
cracking" process, and the slowness and insufficiency of the results.
Our invention relates to a method of conducting the distillation by suitable apparatus
in such a manner that we get the benefit of regular vaporization and condensation
under high pressure and that we may at the same time get such advantage as can be
obtained from "cracking." For this purpose we arrange a suitable boiler or retort
and a condenser in free communication with one another without interposing any
valve between them, but we provide a regulated outlet for condensed liquid from the
condenser. We charge and keep charged the space in the boiler or retort and con-
denser that is not occupied by liquid with gas under considerable pressure, it may be
with air or it may be with carbonic acid gas, or other gas that cannot act chemically
on the matter treated.
The distillation and condensation being thus conducted under considerable pressure,
which can be regulated at will, we obtain from the heavy residue a quantity of more
or less light oil suitable for illuminating and other purposes which cannot be obtained
by distillation under atmospheric pressure:
""
We may also arrange the still head or upper part of the boiler or retort so as to
operate according to the "cracking" method above referred to, the 'cracking'
in this case taking place under high pressure, instead of being carried on under
atmospheric pressure.
The apparatus for effecting distillation in the manner described may be arranged
in various ways.
The accompanying drawings shew one form of apparatus for this
purpose. Figure 1 is a longitudinal and Figure 2 is a transverse section. Figure 3
is a sectional plan on the line X X of Figure 1. A is a fire place with the fire door A¹
and ashpit door A² suited for regulating admission of air as required.
Instead of a fire place with grate for burning solid fuel, any known burners for
liquid or gaseous fuel may be employed.
Above the combustion chamber B is placed a metal retort C which is enclosed
within a refractory casing C' to protect the metal from excessive local heating. The
encased retort is situated in a heating chamber B¹ into which the hot products of
combustion ascend by side ports B2 and from which they pass by central ports B³
into a flue B communicating with a chimney B5. The front part of the retort C
communicates freely with a still head C² provided with a pressure gauge C³ and
safety valve C. The exposed end of the retort C is closed by a readily removeable
cover C³ provided with a glass gauge to shew the level of the liquid in the
retort. D is a pipe coil situated in a tank D¹ in which circulation of water is main-
tained. The upper end of the coil D communicates by a pipe with the still head C²
and its lower end opens to a hollow column D2 which is provided with a glass
gauge D³ and has at the bottom an outlet pipe D' furnished with a stop cock or
valve. E is a pump for forcing the oil to be treated by a pipe E¹ into the
retort C, this pipe preferably extending nearly to the farther end of the retort.
By another pipe E2 furnished with a cock or valve the contents of the retort can
be drawn off, or this pipe may communicate with a second retort which in like
manner may be connected with a third so as to form a series of any required
number. F is an air compressing pump, by which air or suitable gas is forced by
a pipe F into the still head C² or it might be into any other part of the apparatus
which is in communication with the still head. The retort C being partly charged

page_text: with oil by the pump E, and the spaces in the retort C in the still head C² and
in the condensing coil D and the column D2 being charged with air or gas to the
desired pressure, the retort is heated, vaporising the oil under pressure. The oil
vapour is condensed in passing through the coil D and the liquid distillate collects
in the column D2 and is drawn off either continuously or intermittently into suit-
able receptacles in which such gas as may be dissolved in the liquid is liberated and
can be collected.
By a pipe and cock or a suitably loaded safety valve D5 gas may be withdrawn
from the space above the liquid in the column D². Although we have shown one
retort and condenser, there may be several sets of these in communication with the
oil and gas pumps, or with each other, suitable cocks or valves being provided in
the communicating pipes so that the several retorts may be worked simultaneously
or in rotation. From time to time the cover C5 of the retort may be removed to
clear out residue. During the distillation such of the vapour as may be condensed
in the still head C2 or such liquid as may prime up into the still head flows back
into the body of liquid in the retort. By regulating the heat and pressure to which
the retort is subjected, the character of the distillate may be varied and thus oils
more or less light can be obtained to suit various uses. Also the proportions of
the parts may be varied and if necessary means of cooling may be applied to the
still head C².
The method and apparatus above described are obviously applicable not only to
petroleum and other oils, but also to substances generally from which oils can be
distilled in the manner set forth, such for instance as colophony and other resins,
whether they are treated alone or in admixture with other substances. We would
however point out that the substances treated by this process, should preferably be
as free as possible from water so as to avoid generation of steam at high pressure.
In some cases the operation is accompanied by production of permanent gas
which being incapable of condensation, would accumulate and produce abnormal
pressure.
A suitable cock or valve should therefore be provided to allow escape of such gas
from time to time.
Having now particularly described and ascertained the nature of this Inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. The herein described method of distilling mineral oils and like products by
vaporising them and condensing the vapour generated under a regulated pressure
of air or gas.
2. For operating in the manner referred to the combination of a retort or boiler,
a condenser, an oil pump, and an air or gas pump with their communicating pipes,
substantially as described.
Dated this 20th day of March 1800