IMPROVEMENTS. IN TREATING HYDROCARBON OILS
Year: 1860

page_text: LETTERS PATENT to James Stuart, of Vulcan Place, Castor Street;
Poplar, in the County of Middlesex, for the Invention of "IMPROVEMENTS.
IN TREATING HYDROCARBON OILS."
Sealed the 7th February 1861, and dated the 18th August.1860..
PROVISIONAL SPECIFICATION left by the said James Stuart at the
Office of the Commissioners of Patents, with his Petition, on the
18th August 1860.
I, JAMES STUART, of Vulcan Place, Castor Street, Poplar, in the County
of Middlesex, do hereby declare the nature of the Invention for "IMPROVE-
MENTS IN TREATING HYDROCARBON OILS," to be as follows:-
This Invention has for its object improvements in treating hydrocarbon oils,.
and consists in subjecting the hydrocarbon oils to the action of solutions of
chromic acid, by which the odour is removed and matters separated there-
from.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of August, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Stuart, Her special licence that I, the said James
Stuart, my executors, administrators, and assigns, or such others as I,
the said James Stuart, 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 Bri-
tain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN TREATING HYDROCARBON OILS," upon the condition (amongst
others) that I, the said James Stuart, my executors or administrators, by
an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said In-
vention, and in what manner the same was to be performed, and canse
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 James Stuart, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:
This Invention has for its object improvements in treating hydrocarbon oils,
and consists in subjecting the hydrocarbon oils to the action of solutions of
chromic acid, by which the odour is removed and matters separated there-
from.
The process is particularly applicable for purifying the crude oils obtained
by the distillation of bitumen, Rangoon tar, earth oil, and "boghead coal,
which crude oils are mixtures of numerous hydrocarbons; similar crude oils
are obtained from other substances; to the purification of these also my
Invention is applicable.
.
I proceed in the following manner:-I take for every 100 gallons of crude
oil to be treated 12 lbs. 8ozs. of bichromate of potass; this I dissolve in 12
gallons of water, and to the solution'I add 1 gallons of oil of vitriol (the
sulphuric acid of commerce); 'the solution of chromic acid which is thus
obtained I add to and mix with the oil, the whole being kept intimately mixed
by churning or agitating it for about one hour; by this treatment a quantity
of pitchy matters and other impurities are separated from the oil, and the oil
deprived of the greater part of its unpleasant smell; the chromic acid is at

page_text: the same time changed. into oxide of chromium, with which the excess of
sulphuric acid unites and forms sulphate of chromium; the mixture is now
left at rest until separation takes place; this is usually in from one to two
hours, the oil then being the upper portion is drawn off into another vessel,
and agitated with a solution of soda for about one hour; this is done to wash
out or neutralize any carbolic acid or other acids remaining in the oil; the
solution of soda I prefer is. made by dissolving 12 lbs. of soda ash of com-
merce in 12 gallons of water, and I add that quantity to every 100 gallons
of oil to be washed; after one hour's agitation the whole is left at rest until
the oil has separated from the soda solution, after which the oil is placed in an
iron still and distilled; the distillation is continued until the whole bulk of oil
distilled over reaches 840 S. G. at 60° of temperature; the distillate is to be
then placed in a proper vessel and treated as before, by churning or agitating
with a solution of chromic acid in water. .For every 100 gallons of oil to be
treated I dissolve 12½ lbs. of bichromate of potass in 12 gallons of water, and
to the solution I add 1 gallons of oil of vitriol; the compound is mixed with
the oil by agitation for about one hour, and then the whole is left at rest until
the oil is separated from the solution of sulphate of chromium and impurities;
afterwards the oil is drawn off into another vessel, and washed by mixing or
agitating it for half an hour or thereabout, with one-fourth its bulk of water,
or one-fourth its bulk of lime water; when the water or lime water has com-
pletely separated, and the oil has become bright, it will be fit for use as an
illuminating oil. The heavy oil remaining in the still is distilled to dryness,
and may be then treated by any of the known methods for obtaining paraffine
or lubricating oil.
I would remark that the chromic acid used in the process dèscribed above
may be obtained otherwise than from the bichromate of potass; it is, however,
usually most convenient to employ this salt.
I would also remark, that although I prefer to apply the chromic acid in
the first place to the crude oils (because the solution of chromic acid by
removing the pitch, tar, and other impurities from the oil, enables it to be
distilled at a heat much lower than would otherwise be necessary, and so prevents
decomposition taking place in the still), I do not confine myself to the treat-
ment of crude oils, as hydrocarbon oils may sometimes be advantageously
treated with chromic acid after they have been partially refined.
I find that after treating some crude oils with a solution of chromic acid,
and distilling until the distillate or whole bulk of oil distilled over reaches
840 S. G., that the oil so obtained is of too dark a color to be used as an
illuminating oil; in this case I treat the oil by churning or agitating it with

page_text: 2 per cent. by bulk of oil of vitriol for about an hour; then I allow the whole
to rest until the acid tar or sludge has separated from the oil; the oil is then
drawn 'off into another vessel, and agitated with two per cent. of powdered
quicklime or dry chalk for another hour, or until all the smell of sulphurous
acid has left the oil; 25 per cent. (by bulk) of water is then added, and the whole
is agitated for a quarter of an hour, after which time the mixture is left at rest
until the oil has become bright, when it is drawn off for use (but if the oil be
not of a good color I re-distil it). If there is any difficulty in getting the oil
perfectly bright I add to every 100 gallons of oil 25 lbs. of common salt
dissolved in 8 gallons of water, and agitate the whole well together for
quarter of an hour; then, when left at rest, the oil will become perfectly
bright.
In no case, however, do I use oil of vitriol for treating the oil if I can avoid
doing so, for I believe it unites with and decomposes a great part of the
lighter oils, and this I wish to avoid as much as possible.
The chromium used in the process may be recovered either as sulphate or
oxide, as desired. The sulphate of potass formed may also be 'recovered.
In witness whereof, I, the said James Stuart, have hereunto set my
hand and seal, this Ninth day, of February, in the year of our. Lord
One thousand eight hundred and sixty-one..