Process for the Separation and Recovery of Benzol, Alcohol, Ether, and other Easily Volatile Substances from Air or other Gas.
Year: 1892

page_text: Date of Application, 4th July, 1892
Complete Specification Left, 4th Apr., 1893-Accepted, 13th May, 1893
PROVISIONAL SPECIFICATION.
Process for the Separation and Recovery of Benzol, Alcohol, Ether,
and other Easily Volatile Substances from Air or other Gas.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman (a com-
munication to me from abroad by Dr. Christian Heinzerling, of 9 Rotteckstrasse,
Frankfort-on-Main, in the Empire of Germany,) do hereby declare the nature of
this invention to be as follows:-
In several technical operations namely in obtaining coke, tar and ammonia from
coal; in the distillation of peat and of bituminous shale for the purpose of obtaining
oils; in the distillation of wood for acetic acid and obtaining wood spirit; in the
production of smokeless powder or preparation of waterproof texture or tissue;
in the production of chloroform; in the production of carbon bisulphide; in the
production of carbon tetra chloride; where easily volatile bodies are produced
either as products of manufacture or are used as solvents or reagents, the separation
of these bodies when mixed with air or other permanent gases is very incomplete
and imperfect.
The following process obviates this inconvenience.
-
In carrying out the process the air or the gas which contains the before men-
tioned bodies in the form of vapour or gas, if necessary cooled to the temperature
of the atmosphere, is compressed in a compressor to 2-6 atmospheres and then
cooled preferably indirectly by water to 8 10 degrees C. After this the gas or
air is cooled from 20 to - -50 degrees either by direct or indirect cooling. After
this cooling the gases are allowed to expand to normal pressure preferably in a
working cylinder doing work. By this expansion the gases are further cooled,
which amounts according to the greater or less expansion to 20-40 degrees.
-
The separation of the volatile bodies contained in the gases or the air in the
form of vapour or gas takes place in this cooling and expansion either in the form
of a liquid or as a solid body. The gases cooled to 70 or under are used for
cooling the before mentioned compressed gases on the regenerative principle.
These cooled gases may be used for cooling either by passing them through
pipes, which surround the gases to be cooled, or by using them to cool liquids
which have a very low freezing point, -20-40 for example, a solution of
common salt, calcium chloride solution, or glycerine, which liquids may then
be used for cooling the compressed gases, by forcing the same through the
liquids.
Direct cooling by liquids and the choice of the same is materially limited as
the body to be separated must be insoluble or nearly so in the liquid; this method
however may be judiciously used, in the separation of carbon bisulphide, carbon
tetra chloride petroleum benzine and chloroform, which bodies are nearly
insoluble in a solution of calcium chloride, and some of them also are not soluble
in glycerine. Cooling by liquids having low freezing points may however be used
when the bodies to be separated dissolve in the liquid. In this case when a certain
quantity of the latter is dissolved in the liquid, it may be separated by distillation
or by other methods.
On the other hand if such bodies as alcohol, acetone, acetic ether, ether which
is soluble in common salt, and calcium chloride solution, glycerine &c. are
being treated, indirect cooling by surface in the above mentioned way is preferably
chosen.
The cooling apparatus used is similar to those used for cooling gas in the
manufacture of illuminating gas, however other suitable apparatus may be used.
Preferably these are so arranged that the cooling gas circulates inside the

page_text: pipes, whilst the gas to be cooled surrounds the same, or vice versa. The cooling
apparatus is provided with receivers in which the bodies separated collect during
the cooling and may be removed out of the same by suitable emptying apparatus.
If the bodies to be obtained separate in a solid form as carbon bisulphide or
benzene, the removal preferably takes place by removing the cooler and melting
the body by heat.
Of course the removal of the separated bodies may be effected by mechanical
apparatus. The cooled gases entering the working cylinder expand in the cylinder
doing work to about atmosphere over atmospheric pressure, and are thereby again
cooled 20-50° according to the amount of the previous compression.
The last separation takes place in a room, which is provided with sieve like
partitions, which serve for the mechanical separation of solidified bodies from the
After this separation the gases are used for cooling other gases upon the
regenerative principle in the before described manner.
gas.
Dated this 4th day of July 1892.
SYDNEY PITT.
COMPLETE SPECIFICATION.
Process for the Separation and Recovery of Benzol, Alcohol, Ether,
and other Easily Volatile Substances from Air or other Gas.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a com-
munication to ine from abroad by Dr. Christian Heinzerling, of 9 Rotteckstrasse,
Frankfort-on-Main, in the Empire of Germany,) do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
In several technical operations, namely in obtaining coke, tar and ammonia from
coal in the distillation of peat and of bituminous shale for the purpose of
obtaining oils; in the distillation of wood for acetic acid and obtaining wood
spirit in the production of smokeless powder or preparation of waterproof texture
or tissue; in the production of chloroform; in the production of carbon bisulphide;
in the production of carbon tetra-chloride; where easily volatile bodies are pro-
duced either as products of manufacture or are used as solvents or reagents, the
separation of these bodies when mixed with air or other permanent gases is very
incomplete and imperfect.
The following process obviates this inconvenience.
In carrying out the process the air or the gas which contains the before men-
tioned bodies in the form of vapour or gas, if necessary cooled to the temperature
of the atmosphere is compressed in a compressor to 2-6 atmospheres and then
cooled preferably indirectly by water to 8-10 degrees C. After this the gas or
air is cooled from -20 to -50 degrees either by direct or indirect cooling. After
this cooling the gases are allowed to expand to normal pressure preferably in a
working cylinder doing work. By this expansion the gases are further cooled,
which amounts according to the greater or less expansion to 20-40 degrees.
The separation of the volatile bodies contained in the gases or the air in the
form of vapour or gas takes place in this cooling and expansion either in the form
of a liquid or as a solid body. The gases cooled to -70° or under are used for
cooling the before mentioned compressed gases on the regenerative principle.
These cooled gases may be used for cooling either by passing them through pipes,
which surround the gases to be cooled, or by using them to cool liquids which
have a very low freezing point, -20 to -40 for example, a solution of common
salt, calcium chloride solution or glycerine, which liquids may then be used for
cooling the compressed gases, by forcing the same through the liquids.
Direct cooling by liquids and the choice of the same is materially limited as the
body to be separated must be insoluble or nearly so in the liquid, this method
however may be judiciously used in the separation of carbon bisulphide, carbon

page_text: tetra-chloride, petroleum benzene and chloroform, which bodies are nearly
insoluble in a solution of calcium chloride, and some of them also are not soluble
in glycerine. Cooling by liquids having low freezing points may however be used
when the bodies to be separated dissolve in the liquid. In this case when a certain
quantity of the latter is dissolved in the liquid, it may be separated by distillation
or by other methods.
On the other hand if such bodies as alcohol, acctone, acetic ether, ether which is
soluble in common salt and calcium chloride solution, glycerine &c., are being
treated, indirect cooling by surface in the above mentioned way is preferably
chosen.
The cooling apparatus used is similar to those used for cooling gas in the manu-
facture of illuminating gas, however other suitable apparatus may be used.
Preferably these are so arranged that the cooling gas circulates inside the pipes,
whilst the gas to be cooled surrounds the same, or vice versa. The cooling apparatus
is provided with receivers in which the bodies separated collect during the cooling
and may be removed out of the same by suitable emptying apparatus. If the
bodies to be obtained separate in a solid form as carbon bisulphide or benzene,
the removal preferably takes place by removing the cooler and melting the body
by heat.
Of course the removal of the separated bodies may be effected by mechanical
apparatus. The cooled gases entering the working cylinder expand in the cylinder
doing work to about atmosphere over atmospheric pressure, and are thereby again
cooled 20° 50° according to the amount of the previous compression.
The last separation takes place in a room, which is provided with sieve like
partitions, which serve for the mechanical separation of solidified bodies from the
gas. After this separation the gases are used for cooling other gases upon the
regenerative principle in the before described manner.
The annexed drawing illustrates the invention.
a is a crank shaft which is driven in any convenient manner; it "imparts motion
to a rod b. c is a piston on the rod 6 working in the cylinder d of a compressing
pump. The vapour laden air or gas to be treated enters the pump by the pipe e
and is delivered in a compressed state by the pipe f. The other piston on the
rod b works in the cylinder g of a motor engine which receives compressed air or
gas by the pipe h and delivers the air in a cold and expanded state by the pipe i.
The motor engine and the compressing pump are provided with suitable valves
and other usual parts and the work done by the motor aids in operating the pump.
The compressed air or gas passes by the pipe f into the water coolers kk. Each
cooler consists of a nest of pipes; water passes through the pipes and the compressed
air or gas circulates around them. The cold water enters at k' and when it has
become warm passes away at k³.
A pipe leads the compressed air or gas from the water coolers into the air
coolers m m m; these also consist of nests of parallel pipes and here the compressed
air or gas passes through the pipes whilst cold expanded air or gas circulates around
them. The expanded air or gas enters these coolers by the pipe i and after passing
through the coolers escapes at n.
The pockets or receptacles m' m' m' at the bottom of the air coolers are for the
collection of the condensed solvent or material which the air or gas deposits.
o and p are other receptacles provided with the same object.
The number and size of the air coolers depends upon the quantity of the gases to
Obe cooled. A suitable plan is to select the size of the coolers so that the gases in
a compressed state are cooled down to from -25° to -40° C. and afterwards in the
expansion cylinder g further cool to from -60° to -80° C.
If the bodies are separated from the gases in a solid form (such as carburet of
hydrogen or sulphuret of carbon), in order to avoid the danger of stoppage, the
5 coolers should be so arranged that they can be put into and taken out of action
separately. If a stoppage takes place, the cooler affected is shut off from the back
flowing cold gases and a new one is inserted. The melting of the body which has

page_text: become separated in a solid state may be effected by the direct introduction of
uncompressed gases. This method has the advantage that the melting or dissolving
of the solid body can be effected without loss, as the gases which have passed
through the cooler are conducted to the compressor. Of course the hot gases
coming from the compressor could be used for the melting, but this has the
disadvantage that the cooler is easily rendered unsound by great differences
of temperature.
The inflow and outflow pipes and the valves of the expansion cylinder may, if the
separated body is solid, become stopped up or cease to act properly. In order to
avoid this difficulty, a spiral wire may be placed round the valves or inserted in the
pipes, through which wire, in the case of a stoppage, an electric current of a certain
force may be allowed to pass, whereby the adjoining parts are heated and the
melting of the solid body causing the obstruction is effected.
Having particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
The process substantially as described for the separation and recovery of easily
volatile substances from air or other gas charged with the same which process
consists in compressing and then cooling the said air or gas to the temperature
requisite to cause the separation of the volatile substance; the requisite cold being
obtained by the expansion of a previously treated portion of the said air or gas in
an engine doing work, preferably in the compression of another portion of the
vapour laden air or gas.
Dated this 4th day of Anril 1902
CARPMAEL & Co.,
Agents for the Applicant.