An Improved Still for the Extraction of Benzol, Toluol and Xylol from their Admixture with Creosote or other Heavy Oils.
Year: 1898

page_text: Date of Application, 13th Apr., 1898
Complete Specification Left, 13th Jan., 1899-Accepted, 18th Feb., 1899
An Improved Still for the Extraction of Benzol, Toluol and Xylol
from their Admixture with Creosote or other Heavy Oils.
I, WILFRED IRWIN, of Wilton Polygon, Cheetham Hill, Manchester, in the
County of Lancaster, Chemist, do hereby déclare the nature of this invention
to be as follows:-
-
This invention relates to improvements in the process of extraction of benzol,
toluol and xylol from their admixture with creosote or other heavy oils and in
apparatus therefor.
In the ordinary process for the extraction of benzol and its homologues from
scrubbed or washed with heavy oil
gases containing them the latter are
until a few per cent. are absorbed when the mixture is distilled with steam in
large stills or boilers, the hot residual oil being cooled again and employed in a
further treatment of gas. The distillate of benzol eftcetera is condensed and
requires to be re-distilled before treatment with sulphuric acid.
The apparatus heretofore used in this process is both cumbersome and ex-
pensive owing to a greater amount of fuel being necessary for the production of
steam and a very large amount of steam being required to fully extract all the
lighter products from the oil.
The present invention consists of a cylindrical tower built up of a number of
segments, preferably twenty-four, placed one above the other and being similar
in construction to the segments of an ordinary column ammonia still the whole
being placed or fixed on a suitable base with a chamber therein similar to those
above. The uppermost or top segment is provided with a suitable cover in the
centre of which is fixed a pipe leading to a condenser.
At a segment distant from the base (preferably the 16th) the oil containing
the benzol, toluol or xylol is admitted in a regular stream and finding its way
down through the segments it eventually falls into the basal chamber where it
leaves the still by means of a balance pipe.
A jet of steam previously reduced in pressure by means of a reducing valve
to seven pounds, or other pressure as found desirable, is admitted into the seg-
ment above the basal chamber and passes upward through the higher segments
driving the benzol etcetera out of the descending oil. The segments above the
16th (or whichever may be found desirable as a means for charging) act as a
dephlegmating column and thus the oil which may be volatilized along with the
benzol etcetera is. mostly recondensed and a distillate is obtained sufficiently
pure for immediate treatment with sulphuric acid.
The hot oil and condensed steam which leaves the still by the balance pipe
is conveyed to a tank in which is fitted a coil of pipes through which the oil
and benzol etcetera is conducted and by that means heated before entering the
still, and in like manner the oil leaving the still is cooled.
The portion of the column below the sixteenth (or charging) segment is
covered with a non-conducting composition and that above is left uncovered.

page_text: The segments are made of cast iron or other suitable material.
according to the quantity of material required for treatment.
continuous and requires very little attention.
Dated this 12th day of Anvil
1808
The size varies
The process is
W. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.
An Improved Still for the Extraction of Benzol, Toluol and Xylol
from their Admixture with Creosote or other Heavy Oils.
I, WILFRED IRWIN, of Wilton Polygon, Cheetham Hill, Manchester, in the
County of Lancaster, 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 : —
This invention relates to improvements in the process of extraction of benzol,
toluol, and xylol from their admixture with creosote or other heavy oils and in
apparatus therefor.
In the ordinary process of extraction of benzol and its homologues from the
gases containing them such gases are washed with a heavy oil which absorbs
the light hydro-carbons and becomes charged with about or 4 per centum.
The oil is then usually treated in a large still or boiler with steam when the
lighter products are distilled over and the hot residual oil cooled and again em-
ployed in a further treatment of gas. The distillate of benzol is cooled and
condensed but requires to be redistilled before being sufficiently pure for treat-
ment with sulphuric acid.
The apparatus hitherto used for distilling or separating the benzol and its
homologues toluol and xylol is both cumbersome and expensive owing to the
amount of fuel necessary for the production of steam and a very large amount
of steam being required to fully extract all the lighter products from the oil.
My invention consists essentially in constructing a column or tower still with
an inlet for the oil containing benzol etcetera at about two thirds of its height,
and a cooling or dephlegmating chamber above in which many of the impurities
are re-condensed before the benzol toluol and xvlol pass over to the condenser
thus producing a distillate sufficiently pure without further distillation for the
final treatment with sulphuric acid.
In carrying out the invention a tower or column is built up of a number of
segments (say about twenty four) each from 8 to 12 inches in depth placed one
above the other. These segments are similar in construction to the segments
of an ordinary column ammonia still with a hooded passage through which the
steam and vaporized benzol ascend and overflow pipes or passages through which
the heavy oil descends in a steady stream from one to the other. The depth of
the overflow pipes are such that the ascending steam and vapour are caused to
force their way and bubble up through the descending oil.
The column or tower is built upon a suitable base in which is placed a col-
lecting chamber in which heavy oil is collected and drawn off for re-use, the
steam being admitted into the segment above it. The upper or top segment is
fitted with a suitable cover from which a pipe leads to a condenser.
The oil inlet is placed about two thirds the height of the column or tower
through which the heavy oil containing the benzol etcetera is admitted in a regular
stream and gradually passes downward flowing from segment to segment it meets

page_text: the ascending steam and vapour and eventually falls into the basal chamber
from which it flows by means of a balance pipe.
A jet of steam previously reduced in pressure by means of a reducing valve
to seven pounds (or other suitable pressure) is admitted into the segment above
the basal chamber and passes upward through the higher segments driving the
benzol etcetera out of the descending oil.
The chamber above the oil inlet acts as a dephlegmating column and thus
the oil which may be volatilized along with the benzol etcetera is mostly con-
densed and thrown back down the column and a distillate is obtained suffi-
ciently pure for immediate treatment with sulphuric acid.
The hot oil and condensed steam which flows from the receiving chamber at
the base of the column or tower are conveyed into a tank fitted with an ascend-
ing coil of pipe through which the oil charged with benzol etcetera from the
washer is conducted upwards being heated by the oil from the still flowing
down through the tank thus taking up the heat therefrom and at the same time
cooling the oil for further use. The tank is fitted with an overflow through
which the condensed water flows away while the heavy oil is drawn off from the
bottom.
The outlet pipe from the top of the column passes to a condensing coil in
a water tank in which the benzol toluol and xylol are condensed and run into a
receiver.
The lower portion of the column below the oil inlet pipe is covered with a non-
conducting composition and the upper portion is left uncovered and may also
be artificially cooled by any convenient method.
The segments are made of cast iron or other suitable material. The size
varies according to the quantity of material required for treatment. The process
is continuous and requires very little attention.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. A still for the separation of benzol toluol and xylol from creosote or other
heavy oil constructed of segments with a dephlegmating or condensing chamber
above the oil inlet in which the heavier impurities are condensed within the
column leaving the lighter products to pass to the condenser substantially as
described.
2. Apparatus for heating the oil containing benzol &c. and at the same
time cooling the oil after the benzol &c have been extracted constructed and
arranged substantially as described.
3. Apparatus for the separation of benzol toluol and xylol from creosote and
other heavy oil constructed and arranged substantially as described.
Dated th: 10th day of Tanow
1000
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London, Patent Agents.