IMPROVEMENTS IN THE TREATMENT AND UTILIZATION OF ACID GAS TARS
Year: 1872

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 AND UTILIZATION OF ACID GAS TARS."
-A communication from abroad by Ferdinand Blondin, of Paris,
in the Republic of France.
Sealed the 14th June 1872, and dated the 12th January 1872.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 12th January 1872.
I, John Henry JOHNSON, of 47, Lincoln's Inn Fields, in the County
5 of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE TREATMENT AND UTILIZATION OF ACID
GAS TARS," a communication from abroad by Ferdinand Blondin, of
Paris, in the Republic of France, to be as follows :–
=

page_text: Assume that 1 ton of acid oil or tar contains 30 per cent., or, say, 6 cwt.
of sulphuric acid, it is to be treated with about 7 cwt. of common salt dis-
solved in as small a quantity of water as possible (warm water by preference),
say, from 200 to 210 gallons. This warm solution is poured on to the
tar, which at first remains at the bottom of the vessel, but gradually
however after agitation comes to the surface. After being brought into
contact for about an hour the whole is allowed to settle for about ten or
twelve hours; the acid liquor is then drawn off through a discharge cock
provided at the bottom of the vessel, or by means of a syphon. This
acid solution is then to be evaporated to dryness in order to effect the
formation of the neutral sulphate of soda. This operation is to be
carried out by one of the methods employed in the artificial manu-
facture of sulphate of soda and of chlorhydric acid. The retort method
will in all cases be preferable; but it should be observed that as it is
liquid matters which are to be operated upon, it is desirable to commence
the distillation by a concentration in suitable close vessels until the
mass becomes by cooling susceptible of being charged into the retort.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Scal Patent
Office on the 8th July 1872.
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.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of January, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special license
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 thercafter during the term therein
expressed, should and lawfully might make, usc, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
TREATMENT AND UTILIZATION OF ACID GAS TARS," a communication to mo
from abroad by Ferdinand Blondin, of Paris, in the Republic of France,
upon the condition (amongst others) that I, the said John Henry
Johnson, my 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.
THE
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

page_text: of illuminating gas, and in the manufacture of coke. These tars contain
from about twenty-five to about forty per cent. of acid at 60°; their
utilization is therefore of considerable importance.
The process employed according to this Invention for the treatment of
these tars does not differ materially from the process employed for the
utilization of the acid tars which are formed in the treatment and purifi-
cation of schist oils and of petroleum, for which Letters Patent have
been granted to me, dated January Eighteenth One thousand eight
hundred and seventy, No. 153, of which processes the present Invention
constitutes a new application.
The tar from the above-mentioned sources is first completely separated
from the sulphuric acid, so as to render it commercially available, whilst
the sulphuric acid is caused to enter into combination with a basc, which
is of some commercial value.
The acid tar is treated with a solution of common salt in the following
manner :-Assuming that one ton of acidified oil or tar to be operated
upon contains about eight hundredweight of sulphuric acid, eight
hundredweight of common salt is weighed, and is divided into two
equal parts, consisting cach of about four hundredweight, of which
the first part is dissolved in the smallest possible quantity of water,
and the solution poured on to the tar; after agitation and subsidence
the tar comes to the surface, and after being allowed to settle for a
sufficient length of time the liquor, which is composed of a solution of
bi-sulphate of soda and chlorhydric acid, is drawn off.
2 (SO HO)+Na Ol=2 SO³, NaO, Ho+Cl H.
This liquor having been caused to pass into a suitable vessel, the
remaining quantity of about four hundredweight of salt is added; the
mixture is then heated, and is evaporated to a pasty consistence, and
this pasty matter is then passed into the oven or kiln; neutral sulphate
of soda and chlorhydric acid are thus obtained, which are collected
in suitable vessels and condensers.

page_text: This operation will be effected by one of the methods employed in the
artificial manufacture of sulphate of soda and of chlorhydric acid.
The operation is the same for acidified oils, but it requires a shorter
time, about half an hour being in most cases sufficient; and after about
two hours' repose the two liquids (viz. the oil and the saline solution)
will be found to be completely separated.
With regard to the acid liquids resulting from the washing of the
oils, these may be treated directly with salt without previously dissolving
it, and the mixture is subsequently evaporated to dryness, as hercin-
before described, or otherwise.
The anhydrous sulphate of soda obtained in these various cases may
then be dissolved in a small quantity of water in order to effect its
solution, which may be subsequently crystallised.
A manufactory which consumes, say, two hundred tons of sulphuric
acid per annum may produce by this method two hundred tons of 1
sulphate of soda, and upwards of six hundred tons of commercial
chlorhydric acid without taking into consideration the heavy oils or tars
which are converted into commercially valuable products.
The tar which has been separated by this method is then well washed
with water, and after having been allowed to settle for a sufficient 2
length of time the liquor is décanted; the tar is finally treated with a
weak alkaline solution of cither potash or of soda, or with a very weak
ammoniacal solution, or even by means of water. There remains finally
an excellent tar, which is preferable to the heavier tar for a great
number of purposes.
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, -
--
First. The application of the process herein-before described to the
treatment of acid tars resulting from the treatment by means of
sulphuric acid of tars produced in the manufacture of illuminating gas
or of coke.
2
3

page_text: Second. The application of the before-mentioned process to the
treatment of the acidified oils resulting from the treatment of the pro-
ducts derived either from the production of gas or coke, or from the
distillation of products derived therefrom.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and scal, the Eighth day of July
One thousand eight hundred and seventy-two.
J. HENRY JOHNSON. (L.s.)