IMPROVEMENTS IN THE PURIFICATION OF GAS AND THE UTILIZATION OF BYE-PRODUCTS BY THE MANUFACTURE OF SECONDARY PRODUCTS THEREFROM.”
Year: 1877

page_text: LETTERS PATENT to Roger William Wallace, of the Chemical Works, New
Road, Battersea Park, in the County of Surrey, Manufacturing Chemist, and
Carl Friedrich Claus, of Great St. Helen's, in the City of London, Consulting
Chemist, for the Invention of "IMPROVEMENTS IN THE PURIFICATION OF GAS
AND THE UTILIZATION OF BYE-PRODUCTS BY THE MANUFACTURE OF SECONDARY
PRODUCTS THEREFROM.”
"
PROVISIONAL SPECIFICATION left by the said Roger William Wallace and
Carl Friedrich Claus at the Office of the Commissioners of Patents on the 27th
June 1877.
ROGER WILLIAM WALLACE, of the Chemical Works, New Road, Battersea Park,
in the County of Surrey, Manufacturing Chemist, and CARL FRIEDRICH CLAUS, of
Great St. Helen's, in the City of London, Consulting Chemist. "IMPROVEMENTS IN
THE PURIFICATION OF GAS AND THE UTILIZATION OF BYE-PRODUCTS BY THE MANU-
FACTURE OF SECONDARY PRODUCTS THEREFROM."
This Invention relates to improvements in the purification of coal gas, and is a
further development of the processes described in the Specifications filed with our
former applications for Letters Patent, namely, No. 272, dated 20th January, A.D.
1877, and No. 2362, dated 16th June, A.D. 1877.
We find that in addition to the purifying agents described in the said former
Specifications for the removal of bisulphide of carbon from coal gas we can also
employ solutions of sulphide of potassium and sulphide of sodium, either each
separately or mixtures of both.
The solutions of sulphide of potassium or sodium we prepare for the above
purpose by decomposing the sulphates of potassium and sodium by means of
sulphide of barium solution, or by heating, preferably by boiling the solutions of
the sulphates with fresh alkali waste where such is obtainable readily; or by
heating the sulphate of potash or the sulphate of soda, or a mixture of the two,

page_text: with an excess of carbonaceous matter in closed retorts or in reverberatory furnaces,
and dissolving it out in water; or as described in the Specification of Letters
Patent granted to the said Carl Friedrich Claus, dated March 17th, A.D. 1869,
No. 819, or by any other similar method.
As apparatus for the exposure of the coal gas to the purifying action of said
solutions we prefer the use of plant described in our Provisional Specification,
No. 272, though ordinary coke towers or others may, of course, be employed instead
of them, but with less advantage or utility.
As a further improvement, and as another part of our Invention, we propose to
purify the gas from carbonic acid and bisulphide of carbon by exposing the same in
a series of towers of the construction and in the manner also described in the said
former Specification, dated March 17th, A.D. 1869, No. 819, by exposing the crude
coal gas to the action of solutions of the sulphides of potassium and sodium. The
solutions of these sulphides are pumped from the towers (provided for that purpose)
nearest to the gas holder seriatim towards that nearest to the retorts, whilst the gas,
of course, travels in the opposite direction.
By the action of the carbonic acid in the coal gas the solutions of sulphide of
potassium and sodium are gradually converted into the carbonates of potash and
soda, whilst sulphide of hydrogen is liberated.
The speed and the throw of the pumps are so regulated that when the solution
arrives at the last tower of the series it is wholly or nearly converted into a solution
of carbonate of potash or soda, when it is run off into plant separate from the gas
plant, and there boiled down and calcined to form commercial alkalies, as described
in Patent No. 819, dated March 17th, 1869.
By the action of the bisulphide of carbon in the coal gas on the solutions of the
sulphides of potassium and sodium sulpho-carbonate (or allowing for the simultaneous
presence of sulphide of ammonium in the coal gas), sulpho-cyanide of potassium and
sodium are formed; these may be separated from the solutions of carbonites by any
convenient method.
The sulphide of hydrogen liberated in the course of this process travels forward
with the coal gas, and when arrived in another set of towers devoted to its
separation it is there decomposed either in the manner described in Letters Patent
No. 819, dated March 17th, 1869, or by the action of sulphurous acid, as described
in the Specification, No. 272, dated 20th January A.D. 1877, forming free sulphur,
which we utilize.
The towers employed for decomposing the sulphide of hydrogen we construct of
stone or stoneware (similar in construction to that of muriatic acid condensers in
alkali works), and fill the saine with stoneware, angle pieces, stoneware balls, or
tiles. The sulphide of hydrogen may, however, also be absorbed in hydrated oxide
of iron purifiers as at present practised, but we prefer the former method.
In the said foriner Specifications, No. 272, dated 20th January A.D. 1877, and
No. 2362, dated 16th June A.D. 1877, we, state that in the course of purification of
gas by means of ammoniacal gas or caustic ammonia liquor we obtain as ultimate
result solutions of carbonate of ammonia; and we wish to mention now that sesqui
or bi carbonate of ammonia may also be formed in this operation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Roger William Wallace and Carl Friedrich Claus in the Great Seal
Patent Office on the 26th December 1877.
ROGER WILLIAM WALLACE, of the Chemical Works, New Road, Battersea Park,
in the County of Surrey, Manufacturing Chemist, and CARL FRIEDRICH CLAUS, of
Great St. Helen's, in the City of London, Consulting Chemist. "IMPROVEMENTS IN
THE PURIFICATION OF GAS AND THE UTILIZATION OF BYE-PRODUCTS BY THE MANU-
FACTURE OF SECONDARY PRODUCTS THEREFROM.'
"
This Invention relates to improvements in the purification of coal gas, and is a
further development of the processes described in the Specification of our former
Letters Patent, dated 20th January A.D. 1877, No. 272, and of Letters Patent,
dated 16th June A.D. 1877, No. 2302.
We find that in addition to the purifying agents described in the said former
Specifications for the removal of bisulphide of carbon from coal gas we can also
employ solutions of sulphide of potassium and sulphide of sodium, either separately
or mixtures of both.
We prepare the solutions of sulphide of potassium or sodium for the above
purpose by decomposing the sulphates of potash and soda by means of sulphide of
barium solution, or by heating (preferably by boiling) the solutions of the sulphates
with fresh alkali waste, when this substance is readily obtainable; or by heating
the sulphate of potash or the sulphate of soda, or a mixture of them, with an excess
of carbonaceous matter enclosed in retorts or in reverberatory furnaces, and
dissolving it out in water; or as described in the Specification of Letters Patent
granted to the said Carl Friedrich Claus, dated March 17, A.D. 1869, No. 819, or by
any other suitable method.
For effecting the exposure of the coal gas to the purifying action of said solutions
we prefer the use of the apparatus or plant described in Specification of said former
Letters Patent, No. 272, although ordinary coke towers or other means may be
employed instead of the said apparatus, but less advantageously.
As a further improvement, and as another part of our Invention, we purify the
gas from carbonic acid and bisulphide of carbon by exposing the same in a series of
towers and in the manner described in the Specification of Letters Patent, dated
March 17, A.D. 1869, No. 819, by exposing the crude coal gas to the action of
solutions of sulphides of potassium and sodium, produced as above described or
otherwise. The solutions of these sulphides are pumped from the towers (provided
for that purpose) nearest to the gas holder, and through the series of towers towards
that nearest the retort, whilst the gas travels in the opposite direction through the
said scries of towers.
By the action of the carbonic acid in the coal gas the solutions of sulphide of
potassium and sodium are gradually converted into the carbonates of potash and
soda, whilst sulphide of hydrogen is liberated.
The speed and the throw of the pumps are so regulated that when the solution
arrives at the last tower of the series it is wholly or nearly converted into a solution
of carbonate of potash or soda, when it is run off into plant separate from the gas
plant, and then boiled down and calcined to form commercial alkalies, as described
in the Specification of Letters Patent, dated March 17, A.D. 1869, No. 819.
By the action of the bisulphide of carbon in the coal gas on the solutions of the
sulphides of potassium and sodium sulpho-carbonate (or allowing for the simultaneous
presence of sulphide of ammonium in the coal gas), sulpho-cyanide of potassium and
sodium are formed; these may be separated from the solutions of the carbonates by
any convenient method.
The sulphide of hydrogen liberated in the course of the above-described process
travels forward with the coal gas, and enters another set of towers devoted to its
separation; it is then decomposed either in the manner directed in the Specification
of said Letters Patent, No. 819, or by the action of sulphurous acid, as described in

page_text: Specification of Letters Patent, dated 20 January A.D. 1877, No. 272, forming free
sulphur, which may be utilized for any purpose.
The towers employed for decomposing the sulphide of hydrogen are constructed
of stone or stoneware, that is to say, they are similar in construction to muriatic
acid condensers in alkali works, and we fill the same with stoneware, angle pieces,
stoneware balls, and tiles. The sulphide of hydrogen may, however, also be
absorbed in hydrated oxide of iron purifyers as at present used, but we prefer the
other method above specified.
In the said former Specification of Letters Patent, No. 272 and No. 2302, we
state that in the course of purification of gas by means of ammoniacal gas or caustic
ammonia liquor we obtain as the ultimate result solutions of carbonate of ammonia,
and it will be obvious that sesqui or bi carbonate of ammonia may also be produced
in this operation.
Having thus fully described our said Invention and the manner of performing
the same, we wish it understood that we claim,-
First. The purification of coal gas from bisulphide of carbon by means of
solutions of sulphide of sodium and sulphide of potassium, either separately or
together, and produced or obtained in the manner above described.
Second. The purification of coal gas from carbonic acid and bisulphide of carbon
by means of a solution of sulphide of sodium or of sulphide of potassium.
Third. The manufacture of carbonate of soda and of carbonate of potassa by the
evaporation and calcination of the residual liquor obtained in or resulting from the
.above-described process of purification.
Fourth. The decomposition of the sulphide of hydrogen obtained by the action
of carbonic acid on the above-named sulphides by means of sulphurous acid, and
the production of the solid sulphur resulting from such decomposition.
Fifth. The employment of stone towers, as above described, for scrubbers when
sulphurous acid is used as a purifying agent.
In witness whereof, I, the said Carl Friedrich Claus, for myself and on behalf
of the said Roger William Wallace, have hereunto set my hand and seal,
this Twenty-fourth day of December, in the year of our Lord One thousand
eight hundred and seventy-seven.
CARL FRIEDRICH CLAUS. (L.S.)