IMPROVEMENTS IN THE TREATMENT OF THE REFUSE OR SLUDGE OIL PRODUCED IN THE DISTILLATION OR PURIFICATION OF CRUDE PETROLEUM, ASPHALTE, BITUMEN, AND OTHER SUBSTANCES FROM WHICH HYDROCARBON OILS ARE OBTAINED, THE OBJECT OF SUCH TREATMENT BEING TO OBTAIN USEFUL PRODUCTS THEREFROM."
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by William Edward Newton at the
Office of the Commissioners of Patents on the 11th May 1876. A com-
munication from abroad by Walter P. Jenney, of New York, in the United
States of America.
WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Civil Engineer. "IMPROVEMENTS IN THE TREATMENT OF
THE REFUSE OR SLUDGE OIL PRODUCED IN THE DISTILLATION OR PURIFICATION
OF CRUDE PETROLEUM, ASPHALTE, BITUMEN, AND OTHER SUBSTANCES FROM WHICH
HYDROCARBON OILS ARE OBTAINED, THE OBJECT OF SUCH TREATMENT BEING TO
OBTAIN USEFUL PRODUCTS THEREFROM."
In the purification of hydrocarbon oils produced by the distillation of crude
petroleum, asphaltes, or bitumens, or by the destructive distillation of coal, resins,
or bituminous shales, the oils are agitated with two per cent. or more of concen-
trated sulphuric acid in order to remove certain oils contained in the distillate
which would in course of time absorb oxygen from the air and cause the oil to
become dark colored and gummy, and also to remove tarry substances and the
disagreeable odour.
Sulphuric acid combines chemically with these bodies and dissolves them,
forming a dark and heavy liquid, which settles on the bottom of the agitator
and can then readily be drawn off from the purified oil, this peculiar compound
of sulphuric acid and hydrocarbon oils dissolved in the excess of acid is known
as "sludge." If mixed with a little water the compound of acid and oil is decom-
posed, producing a weaker acid and a dark colored offensive oil which rises to
the surface of the acid and usually is thrown away, no commercial use having
been found for it. This waste product is called "sludge oil."
In carrying out the present Invention the sludge is agitated in a tank with
about 5 per cent. of petroleum naphtha, which dissolves the free oil, and on
allowing the sludge to remain at rest this rises to the top and is removed. The
sludge is then decomposed by the addition of water, and the sludge oil which rises
on the top of the mixture of acid and water is drawn off and saved. The sludgo
oil is then purified by repeated washings with water until the acid remaining in
it is removed. Any remaining traces of acid in the oil are then neutralized by
quick lime or caustic soda. The purified oil contains about ten per cent. of
volatile oils, which are converted into a hard resin. To remove these volatile
substances sludgo oil thus purified is introduced into a still with the addition of
[Price 2d.]

page_text: from two to four per cent. of caustic soda, or caustic soda and about two per cent.
of the oxides of lead or manganese, and steam is then blown through the oil until
no more volatile oils are removed. The steam is then shut off and the contents
of the still allowed to settle, when a sediment of tarry impurities and soda
subsides from which the pure oil may be drawn off. The oil is then introduced
into a still or tank and oxidised by blowing currents of air through it. The action
of the air is continued until a sample taken from the contents of the converting
vessel is on cooling found to be a resinous substance of a greater or less hardness
or consistency. After allowing the contents of the still to settle the hot resin is
drawn off from the sediment of soda and impurities. An inferior quality of this
resinous substance may be produced by treating the washed sludge oil in a still
with caustic soda and litharge and blowing a current of hot air through it. To
produce the lightest colored resins the sludge oil is steamed with five per cent. of
soda at a low temperature to remove the more volatile portions, and is then oxi-
dized and bleached by exposing the oil in shallow tanks covered by glass to the
sunlight, the oil being kept hot and fluid by a steam coil in the bottom of the tank,
and currents of air blown through it to produce the oxidation.
Inferior qualities of sludge oil which contain a large quantity of tarry substances
are treated as follows:-The oil is charged into a still and caustic soda and black
oxide of manganese are added and the charge distilled by a current of steam blown
through the oil assisted by a fire under the still until only tar and coke remain
behind.
By the use of steam under pressure, especially when superheated, the oil can
be distilled with scarcely any decomposition, and the distillate which is of a yellow
or light red color can be converted into a superior light colored resinous substance
by oxidizing it with currents of air at the lowest possible working temperature.
A good varnish may also be produced from the resinous substance before
described by dissolving or mixing it either with or without the aid of heat with
such solvents as will completely and perfectly dissolve the resinous substance and
produce a useful varnish.
Petroleum naphtha readily dissolves the resinous substance (even without the
aid of heat) and produces an excellent varnish which dries very quickly.
Turpentine completely dissolves the resinous substance, especially when aided
by heat, and produces n varnish useful for many purposes.
Benzol and coal tar naphtha also quickly dissolve the resinous substance and
produce a varnish.
Linseed oil and other drying oils or a mixture of these with turpentine, petroleum,
and naphtha, dissolve the resinous substance readily when aided by heat, forming
slow drying oil varnishes.