IMPROVEMENTS IN THE BLEACHING OR PURIFICATION OF PETROLEUM AND OF OTHER DISTILLABLE OILS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Richard Baynes, John Fearenside
Junior and William Phillips Thompson at the Office of the Commissioners
of Patents on the 31st December 1883.
RICHARD BAYNES and JOHN FEARENSIDE Junior both of Liverpool in the county
of Lancaster, Patentees, and WILLIAM PHILLIPS THOMPSON of the same place,
Patent Agent and Scientific Expert. " IMPROVEMENTS IN THE BLEACHING OR
PURIFICATION OF PETROLEUM AND OF OTHER DISTILLABLE OILS."
Mineral oils, and other oils of a distillable nature such as rosin oil, are often of a
very dark nearly black color and are very offensive. The color is usually extracted
and destroyed by acids or alkalies or both; the odour is destroyed by sweating
with moist steam at low pressure, and the odour flys off with the steam. Now we
have discovered that the odour being in large part sulphuretted and unsulphuretted
bydrocarbons, can be in part decomposed by chemicals having a strong affinity for
sulphur and in part condensed into very valuable naptha. We accordingly before
or after the fractional distillation, or even as its first step, distil off these vapours
Instead of
by blowing through the oil ordinary wet steam in the usual manner.
however allowing the fumes to escape into the air, we condense them and thus
obtain crude naptha.
This crude naptha is then purified by being mixed with charcoal or other
indifferent absorbent powder and distilled through dry powdered charcoal coke or
other absorbent granular indifferent matter mixed with chloride of zinc or other
sulphur-loving compound, or through granular hydrated sesquioxide of iron or both
successively.
We now treat the oil freed from naptha or otherwise in the following manner.
We take powdered charcoal or other absorbent not liable to be decomposed, dissolved,
melted, or altered in composition, by the oil except in so far as it is altered by
absorbing the coloring matter, and mix it with the crude oil to the consistency of
mud; we then distil the oil off by fractional distillation or otherwise and with or
without superheated steam, and we find that nearly all the coloring matter remains
behind in the powder. The powder can be used for a fresh operation. To still
further improve the color we prefer to pass the fumes through dry granular
charcoal heated to the evaporation point of the oil. This charcoal can be in one

page_text: or more purifiers arranged to work in series as in gas works, but heated with steam
jackets, or hot air jackets or by the injection of superheated steam.
We have already tried as absorbing powders wood, charcoal, coke, bone ash,
fullers earth, china clay, alumina earths, both burnt and unburnt, and have found
all to answer more or less, but that ordinary metallurgical coke or wood charcoal
steeped in a saturated solution of sulphide of zinc and well dried act best of any
of these materials. We find however that the material whatever it be must be
absolutely dry to have the desired effect. The form of still is almost immaterial as
we find that the oil seems to pass through the porous material to the sides of the
still by capillary attraction and distil off without any necessity for stirring
mechanism, and that the coke or charcoal used at the end of the operation is
granular or pulverulent and ready to be used for mixing with more oil for a fresh
operation.
The object of impregnating the charcoal with chloride of zinc is to deprive the
oil at the same time of its sulphur compounds and other like matters. It is obvious
however that instead of impregnating the charcoal with it, the two substances can
be used separately or in some cases hydrated sesquioxide of iron lime or other
sulphur-loving matter could be used. We find also that other soluble salts of zinc
such as the sulphate, also similar soluble salts of iron and of several other metals
will answer, in fact almost any salt having a base with greater affinity for sulphur
than for the acid in combination with that base. The plan we have set forth in
the specification of impregnating charcoal or coke with anhydrous chloride of zinc,
we find superior to and more economical than any other.