IMPROVEMENTS IN THE PURIFICATION OF COAL GAB
Year: 1869

page_text: LETTERS PATENT to Astley Paston Price, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Consulting Chemist, for the Invention
of "IMPROVEMENTS IN THE PURIFICATION OF COAL GAB."-A communi-
cation from abroad by Eugene Pelouze, of Paris, in the Empire of
France, Chemist.
Sealed the 8th March 1870, and dated the 18th October 1869.
PROVISIONAL SPECIFICATION left by the said Astley Paston Price at
the Office of the Commissioners of Patents, with his Petition, on
the 18th October 1869.
I, ASTLEY PASTON PRICE, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Consulting Chemist, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE PURIFICATION OF COAL GAS," a
communication to me from abroad by Eugene Pelouze, of Paris, in the
Empire of France, Chemist, to be as follows:-
This Invention relates to an improved method of effecting the separa-
tion of certain impurities, such as ammonia and sulphuretted hydrogen,
which are contained in crude and impure coal gas, and consists, first, in
the employment of sawdust or other divided porous substance, organic

page_text: or mineral, in conjunction with sulphuric acid, which by preference has
been previously diluted with water, together with such substances as are
now generally employed for effecting the purification of gas, such, for
example, as the oxides of iron, either before or after they have undergone
the process of revivification.
In carrying out this Invention the sawdust or other porous material
may either be first impregnated with the diluted acid, and after having
been dried by exposure or otherwise may be mixed with other purifying
agents, such as oxide of iron or revivified material, or the sawdust or
other porous material may be mixed with the oxide of iron or the
revivified materials, and then the diluted sulphuric acid he added, and
after the materials have, if necessary, been dried by exposure or otherwise
they may be placed in what is known as a dry purifier and the impure
gas be conducted through the same, as is well understood. From time
to time as the sulphuric acid becomes saturated with ammonia it will
be found desirable to add additional quantities of the diluted sulphuric
acid, which is done by preference when the materials have undergone the
process of revivification, as is well understood.
The proportions in which I prefer to employ the diluted sulphuric acid
are about two parts by weight of real vitriol to every one hundred parts
of purifying material or mixture, but other proportions will give good
results.
The second part of my Invention relates to the employment of sul-
phuric acid by preference previously diluted in conjunction with oxide
of iron, or the oxides of iron resulting from the revivification of the
before-mentioned purifying agents or materials, by which means their
power of effecting the abstraction of ammonia and of sulphuretted
hydrogen is increased and the abstraction of those impurities is more
easily effected.
The sulphate of ammonia formed by the abstraction of the ammonia
and contained in the purifying materials may be extracted by means of
water, as is well understood.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Astley Paston Price in the Great Seal Patent
Office on the 12th April 1870.
TO ALL TO WHOM THESE. PRESENTS SHALL COME, I, ASTLEY
PASTON PRICE, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Consulting Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of October, in the
year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-third year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Astley Paston Price, Her special license
that I, the said Astley Paston Price, my executors, administrators, and
assigns, or such others as I, the said Astley Paston Price, 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 make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE PURIFICATION OF COAL GAS," a communication from abroad by Eugene
Pelouze, of Paris, in the Empire of France, Chemist, upon the condition
(amongst others) that I, the said Astley Paston Price, 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.
NOW KNOW YE, that I, the said Astley Paston Price, 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, that is, to say :-.
The said Invention relates to an improved method of effecting the
separation of certain impurities, such as ammonia and sulphuretted
hydrogen, which are contained in crude and impure coal gas, and
consists, first, in the employment of sawdust or other divided porous.
substance, organic or mineral, in conjunction with sulphuric acid which
has been previously diluted with water, together with such substances

page_text: as are now generally employed for effecting the purification of gas, such,
for example, as the oxides of iron, either before or after they have
undergone the process of revivification.
In carrying out this Invention the sawdust or other porous material
may either be first impregnated with the diluted acid, and after having
been dried by exposure or otherwise may be mixed with other purifying
agents, such as oxide of iron or revivified material, or the sawdust or
other porous material may be mixed with the oxide of iron or the
revivified materials, and then the diluted sulphuric acid be added, and
after the materials have, if necessary, been dried by exposure or
otherwise they may be placed in what is known as a dry purifier and
the impure gas be conducted through the same, as is well understood.
From time to time as the sulphuric acid becomes saturated with
ammonia it will be found desirable to add additional quantities of the
diluted sulphuric acid, which is done either before or after the materials
have undergone the process of revivification, as is well understood.
The proportions in which I prefer to employ the diluted sulphuric acid
are about two parts by weight of real vitriol to every one hundred parts
of purifying material or mixture, but other proportions will give good
results. The degree or state of dilution of the sulphuric acid which has
been found to give good results is about one part by weight of sulphuric
acid or vitriol to about five parts by weight of water, but other proportions
may be employed..
In carrying out the first part of this Invention I prefer to saturate
the mixture of sawdust and oxide of iron with the diluted acid, and
then to dry or dessicate the acidified mixture by exposure to the air or
otherwise. The dessicated materials are then placed in an ordinary
purifier, and the impure gas is allowed to pass through the same until
the sulphuric acid contained therein is saturated; the materials are then
to be watered with another portion of the diluted sulphuric acid, and
the impure gas is allowed to pass through the same until the acid is
neutralized, and this process may be repeated until such time as that
the materials shall have become choked or clogged with impurities, such
as tarry matter, naphthaline, and other products, or until it is found
necessary to submit the contents of the purifyer to what is known as
a revivifying process, that is to say, exposing the mixture containing
the spent oxide of iron to the action of the atmosphere.
From
the spent or from the revivified material the sulphate of ammonia

page_text: may be obtained by lexiviating with water and then evaporating, as is
well understood. The revivified or the revivified and lexiviated material
may be again saturated with dilute acid, dried, and be again employed,
as before mentioned. In adopting this method of purification it will be
found that the sulphuretted hydrogen will be readily removed as well
as the ammoniacal impurities, and that naphthaline, should such be
contained in the gas, will be separated from the impure gas.
The second part of this Invention relates to the employment of
sulphuric acid previously diluted with water in conjunction with oxide
of iron or the oxides of iron resulting from the revivification of the
before-mentioned purifying agents or materials, by which means their
power of effecting the abstraction of ammonia and of sulphuretted
hydrogen is increased and the abstraction of those impurities is more
easily effected.
In carrying out the second part of this Invention I treat the oxide
of iron intended for the purification of coal gas with diluted sulphuric
acid, and after the impure gas has passed through the same and the
acid has become saturated with ammonia I moisten the purifying
materials with diluted acid and again allow the gas to pass through the
purifyer, which operations may be repeated. When the oxide of iron
has ceased to abstract the sulphuretted hydrogen the material is to be
subjected to the revivifying process by exposure to air, and after the
extraction of the sulphate of ammonia by lixiviation with water the
residual oxide of iron may be again submitted to the treatment with
diluted sulphuric acid, as before mentioned. The sulphate of ammonia
formed by the abstraction of the ammonia and contained in the purifying
materials may be extracted by means of water, as is well understood.
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 employment for the purification of coal gas of porous
materials, such, for example, as sawdust, which have been previously
impregnated with dilute sulphuric acid and have undergone, when
necessary, a process of drying.

page_text: Second. The employment of the before-mentioned materials, after
having undergone the treatment described in conjunction with oxide of
iron for the purifycation of impure gas.
Third. The employment for the purification of gas of oxides of iron
which have been submitted to the treatment with diluted sulphuric
acid, as before described.
Fourth. The employment of diluted sulphuric acid in the manner and
for the purpose herein described.
In witness whereof, I; the said Astley Paston Price, have to this
my Specification set my hands and seal, this Twelfth day of April 1
One thousand eight hundred and seventy.
ASTLEY PASTON PRICE. (L.S.)