IMPROVEMENTS IN THE TREATMENT OF ACID TARS OBTAINED FROM BOG- HEAD MINERAL SCHIST OR PETROLEUM
Year: 1870

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN THE TREATMENT OF ACID TARS OBTAINED FROM BOG-
HEAD MINERAL SCHIST OR PETROLEUM.”—A communication from abroad
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
^
the 18th January. 1870:
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields; in the
County of Middlesex, Gentleman, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE TREATMENT OF ACID TARS OBTAINED
FROM BOGHEAD MINERAL SCHIST OR PETROLEUM," a communication to me from
abroad by Gervais Chevrier, of Paris, in the Empire of France; to be as
follows:-
•
This Invention relates to the treatment of acid tars obtained from the
distillation of bituminous schist, boghead mineral, or petroleum with a

page_text: view to rendering such tar and the products it contains commercially
available.
In carrying out this Invention the acid tar is treated with a solution
of common salt, whereby the sulphuric acid is completely separated in
the state of sulphate of soda.
SO³, HO+Nacl, = SO³, NaO + Hcl.
The crystallized sulphate of soda is represented by the formula SO³,
NaO + 10 HO, and its weight is equal to 3.28 times that of the
sulphuric acid and about 3 times that of the common salt employed.
Suppose a reservoir be employed containing, say, 1,200 lbs. of crude oil,
to this oil there is to be added from 50 to 60 lbs. of sulphuric acid by
which means about 200 lbs. of acid tar will be obtained. This tar is
treated with from 70 to 75 lbs. of common salt dissolved in about from
250 to 300 lbs. of hot water. This hot solution is poured upon the tar
which then remains in the bottom of the reservoir, but by degrees on
being agitated it loses its acid and comes to the surface. After this
treatment has been carried on for about one hour the whole is left to
repose for about 10 or 12 hours, when the acid liquor is drawn off by a
cock situate at or near the bottom of the vessel and. is concentrated in
order to crystallize the sulphate of soda. This operation yields from
180 to 200 lbs. of this salt. The tar is next well washed, the agitation
causing it to descend to the bottom of the vessel; this is decanted after
it has been allowed to settle, and the. tar is recovered by a. weak
*alkaline solution of potass or soda, or by a weak ammoniacal water, or
even by ordinary water alone.
Ammonia may moreover be substituted for the common salt where
convenient. Sulphate of ammonia will thus be obtained, the commercial
value of which is becoming more and more important daily.
Finally, there remains 130 to 140 lbs. of excellent tar which is
preferable for many purposes to tar of a heavier nature.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
i..
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 18th July 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
:

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of January, in the year.
of our Lord. One thousand eight hundred and seventy, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special licenṣa
that I, the said John Henry Johnson, my executors, administrators,
and assigns, or such others as I, the said John Henry Johnson,
my executors, administrators, or 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, makė,
use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN THE TREATMENT OF ACID TARS OBTAINED FROM
BOGHEAD MINERAL SCHIST OR PETROLEUM," a communication from abroad
by Jervais Chevrier, of Paris, in the Empire of France, upon the
condition (amongst others) that I, the said John Henry Johnson, mỵ
executors or administrators, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed,
and cause 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 John Henry Johnson, do hereby
declare the nature of the said Invention, and in. what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the, accom-
panying Drawings, and to the letters and figures marked thereon, that
is to say:-
The said Invention has for its object the converting into commercial
products the acid tars or oils derived from the treatment, and purifi-.
cation of schist oils and petroleum. The process consists in completely
separating the tar so as to render it commercially available, and to form
the sulphuric acid into a combination having a commercial value which
may become equal to that of the acid itself and of the reagent employed.
If acid tar be treated with a solution (as concentrated as possible) of
conimon salt the sulphuric acid will be completely separated in the.
form of sulphate of soda.
802
1

page_text: Assume two thousand pounds of acid tar or oil containing thirty per
cent. say six hundred pounds of sulphuric acid, this is to be treated with
seven hundred and twenty pounds of common salt dissolved in the
smallest possible quantity of water (by preference warm water), say from
one hundred and eighty to one hundred and ninety gallons. The warm
solution is poured upon the tar, which remains at first at the bottom of
the vessel, but by degrees it loses its acid and rises to the surface. After
one hour's treatment the whole is allowed to settle for ten or twelve hours
and the acid liquor is then drawn off by a discharge cock disposed at the
bottom of the trough, or by a syphon. This acid solution having been
evaporated to dryness and heated until it assumes a thick or pasty
condition will yield neutral sulphate of soda. This operation may be
carried out by any of the methods employed in the manufacture of
sulphate of soda and chlorhydric acid, The furnace method will in all
cases be preferable, it being observed that as the operation is performed
on liquids it is useful to commence the distillation by concentration in
suitable closed vessels until the mass becomes upon cooling capable of
being charged into the furnace.
I have shewn in the Drawing hereunto annexed an arrangement of
furnace which I consider suitable for this operation, and which will be
herein-after described.
The operation is the same for acid oils, but it is of shorter duration,
one-half hour of contact is sufficient, and after two hours settling the
separation of the two liquids (the oil and saline solution) is complete.
With regard to the acid waters resulting from the washing of the oils
these are treated directly with salt without dissolving it, and are
evaporated to dryness as herein-before described,
The anhydrous sulphate of soda obtained in these various processes
may be then dissolved in a small quantity of water slighty heated (two
thousand pounds of this salt requires from six hundred pounds to six
hundred and forty pounds of water at a temperature of from eighty-six
degrees to one hundred and four degrees Fahrenheit), and on cooling there'
are deposited voluminous crystals of Glauber's salt, SQ³, Nao + 10 Ho.
The tar which has been separated is then washed with a large quantity of
water, and after being allowed to settle for a sufficient time and after
decanting the operation is completed and the tar is then treated with a
weak alkaline solution.

page_text: Ammonia may be substituted for common salt where that alkali' is
produced near the works, sulphate of ammonia is then obtained, the
commercial value of which is becoming daily enhanced.
There remains finally an excellant tar which is preferable to the
heavier tar for many purposes.
And in order that this Invention may be more fully understood I shall
now porceed more particularly to describe by an example the course
of the operations, and for that purpose shall refer to the two Figures
on the annexed Sheet of Drawings, which represent the furnace designed
to carry out my. Invention, the same letters of reference indicating
corresponding parts in both Figures.
Figure 1 is a longitudinal vertical section taken along the line A, B,
Figure 2, and Figure 2 a horizontal section taken along the line C, D,
(Figure 1) of the type of furnace it is proposed to employ for concen-
trating and calcining the sulphate of soda.
a are the evaporating boilers; b, the refractory hearth of the calcining
furnace; c, furnaces for heating the boilers a; d, the smoke flues of the
furnaces c; e, tubes for conducting into vessels the chlorhydric acid
evolved in the boilers a; f are pipes for conducting the pasty substances.
into the calcining furnace; 9, the cocks of the tubes.f; and h, apertures
provided to give access to those cocks; i is the fire-place of the calcining
furnace, and are the smoke flues; k is the refractory vault of the
hearth 6; is a tube for conducting the acid from the calcining furnace
into vessels; and m the common chimney of the furnaces.
2
The furnace consists of two evaporating boilers a disposed one on each
side of a hearth 6, in which the calcination of the sulphate is effected.
The boilers are composed of cast iron lined with lead, and are heated by
a fire c, the flames of which are distributed along the flues d, which
surround the whole surface of the boilers. The acid vapours cooled
during the concentration escape through the tubes e into vessels disposed
round the furnace, where they are condensed. After boiling for a certain
time in the boilers a the solution assumes a somewhat pasty condition,
which admits of being passed into the calcining furnace through tubes if
provided for that purpose at the lower part of the boilers, such tubes
being closed by cocks g to which access may be readily obtained through
apertures formed in the brickwork.

page_text: The calcining furnace, which is disposed between the two concentrating
boilers, is composed essentially of a hearth 6, which is heated by a fire i,
the flues of which completely surround its lower portion. The hearth
and the vault k above it are made entirely of refractory materials, and a
tube which is disposed at the upper part of the furnace conducts the
acid vapours into the vessels which have already received the con-
densation of the vapours from the concentrating boilers, and which
become completely saturated with chlorhydric acid. The calcined
sulphate is withdrawn through an aperture formed above the door of the
fire-place i.
On the annexed Drawing the chimney m which is situate at about the
centre of the wall receives the products of combustion from the three
fires, but it will be readily understood that the arrangement, together
with that of the smoke flues, may be varied as required.
I shall now proceed to explain by an example the general course of
the operations which characterize this process, and the method of carrying
it out by means of this system of furnace,
Assuming that it is required to treat at each operation a quantity of tar
containing about four hundred pounds of sulphuric acid, or say in this case
about five hundred and sixty pounds, the tar is introduced into a vessel
lined with lead of a capacity of from one hundred and forty to one hundred
and sixty gallons. The operator takes four hundred and eighty pounds
of common salt (two hundred pounds SO HO, requiring two hundred
and forty pounds of salt), about two hundred pounds of which, or rather
less than one half, is placed aside; the rest is then dissolved in about
forty gallons of warm water, and the partially dissolved salt is poured on
the acid tar; acid sulphate of soda is thereby formed, and the excess of
salt dissolves. The vessel then contains about one thousand pounds of
the liquid, which is withdrawn and poured into one of the evaporating
boilers. Chlorhydric acid is distilled under the influence of heat, and is
collected in vessels provided for that purpose. When the contents of the
boiler have assumed almost a pasty condition they are transferred to the
furnace, where the remainder of the before-mentioned proportion of salt has
been disposed, and then the whole is gradually heated. The chlorhydric
acid gas which is evolved passes into the vessels before referred to,
whereby the acid is collected and made commercially available.
:

page_text: There will thus be obtained in twelve or 13 hours' working four
thousand pounds of chlorhydric acid at about twenty-one degrees
Baumé, three thousand four hundred pounds of anhydrous sulphate of
soda perfectly pure, and one thousand pounds of tar neutralized and
purified, which may be employed as fuel in conjunction with coal or coke
or otherwise.
The form and dimensions of the apparatus and furnace may be
modified according to circumstances, and the apparatus may be worked
continuously or intermittently. If a furnace composed of refractory ·|
clay be substituted for the boiler lined with lead the evaporation and
calcination may be effected in the same chamber.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be
used or carried into effect, I would observe in conclusion that what I
consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent is, the
treatment of acid tars by means of chloride of sodium or by means of
ammonia so as to utilize the sulphuric acid contained therein, and to
render the tars more suitable for economic purposes..
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, this Thirteenth day of
July One thousand eight hundred and seventy.
J. HENRY JOHNSON. (L.S.)